text stringlengths 454 608k | url stringlengths 17 896 | dump stringclasses 91
values | source stringclasses 1
value | word_count int64 101 114k | flesch_reading_ease float64 50 104 |
|---|---|---|---|---|---|
🚨 Pooch v1.2.0 is the last release that is compatible with Python 3.5. 🚨
About¶¶
For a scientist downloading a data file for analysis:
from pooch import retrieve # Download the file and save it locally. Running this again will not cause # a download. Pooch will check the hash (checksum) of the downloaded file # against the given value to make sure it's the right file (not corrupted # or outdated). fname = retrieve( url="", known_hash="md5:70e2afd3fd7e336ae478b1e740a5f08e", )
For package developers including sample data in their projects:
""" Slack where you can ask questions and leave comments.
Citing Pooch¶
This is research software made by scientists (see AUTHORS.md). Citations help us justify the effort that goes into building and maintaining this project. If you used Pooch for your research, please consider citing us.
See our CITATION.rst file to find out more.)
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#include <Dhcp4.h>
Definition at line 311 of file Dhcp4.h.
The EFI DHCPv4 Protocol driver operating state.
Definition at line 315 of file Dhcp4.h.
The configuration data of the current EFI DHCPv4 Protocol driver instance.
Definition at line 319 of file Dhcp4.h.
The client IP address that was acquired from the DHCP server.
If it is zero, the DHCP acquisition has not completed yet and the following fields in this structure are undefined.
Definition at line 324 of file Dhcp4.h.
The local hardware address.
Definition at line 328 of file Dhcp4.h.
The server IP address that is providing the DHCP service to this client.
Definition at line 332 of file Dhcp4.h.
The router IP address that was acquired from the DHCP server.
May be zero if the server does not offer this address.
Definition at line 337 of file Dhcp4.h.
The subnet mask of the connected network that was acquired from the DHCP server.
Definition at line 341 of file Dhcp4.h.
The lease time (in 1-second units) of the configured IP address.
The value 0xFFFFFFFF means that the lease time is infinite. A default lease of 7 days is used if the DHCP server does not provide a value.
Definition at line 347 of file Dhcp4.h.
The cached latest DHCPACK or DHCPNAK or BOOTP REPLY packet.
May be NULL if no packet is cached.
Definition at line 351 of file Dhcp4.h. | http://dox.ipxe.org/structEFI__DHCP4__MODE__DATA.html | CC-MAIN-2019-04 | refinedweb | 242 | 78.65 |
At the recent PCP developers meeting there was a suggestion to 1. drop the binary format of the PMNS and 2. remove our dependence on cpp being installed to pre-process the ASCII PMNS before it is parsed. 1. makes sense because the "performance" optimization of the compiled PMNS was justified long ago when all client apps had to load the full PMNS from a local copy, but those days are long gone. Now, outside QA and some very rare uses, pmcd is the only one to load a PMNS and this only happens at pmcd start up or when a PMDA is added or dropped. So this is a sensible candidate for PCP 4.0. 2. is of a bit more immediate interest as it could be included in PCP 3.x. I've completed the code in libpcp to do - #include "file" and #include <file> (from $PCP_VAR_DIR/pmns) - stripping /* ... */ comments within the line and across lines - #define macro handling (v. simple linear symbol table) - macro substitution in the metric name and PMID But now I've hit an obstacle ... although what is done so far is enough for the installed PMNS in $PCP_VAR_DIR/pmns/root (which contains no cpp directives), the components of the PMNS from the various PMDAs (and some of the QA tests) include all of the above, _plus_ - #ifdef ... #endif - #ifndef ... #endif - #undef Fortunately no one uses #if and I'm not going there! So now there are a number of options, and it is unclear which to take and I'd appreciate some feedback. A. Continue with the changes to date ... it is only code and not too hard ... but it is adding considerable (little used) bloat to libpcp B. Do A. and then rip all of the code out of libpcp and create our own mini-cpp application that is shipped and hidden in $PCP_BINADM_DIR C. Take an existing cpp with a compatible open source licence and bundle that with PCP ... I've looked at the GNU one, but cannot easily see how to unbundle it from the morass of the gcc build environment. Another option is mcpp from which builds simply, but I have no idea about the quality of the code and it has a BSD-style licence. Are there other options in this category? D. Give up and maintain the status quo. What do you think? | http://oss.sgi.com/pipermail/pcp/2011-June/001809.html | CC-MAIN-2015-22 | refinedweb | 396 | 71.44 |
Deciding how to add email sending capabilities to a web application is always difficult. Do you go through the trouble of setting up and maintaining your own email server, or do you opt for a third-party email service? While the answer is dependent on a number of variables such as volume of emails, your hosting platform and your budget, the tendency is often to favor the simplicity offered by a dedicated email service.
In this tutorial you’ll learn how to configure an application based on the Flask framework and the Flask-Mail extension to deliver email through the Twilio SendGrid service.
Tutorial Requirements
To follow this tutorial.
SendGrid Configuration
Before you can send email through SendGrid, you have to create an API key that you will use to authenticate. Log in to your SendGrid account, then click on the left sidebar, select Settings and then API Keys. Click the “Create API Key”.
You need to give your API key a friendly name. For this tutorial I chose the name Flask-Mail. I selected “Full Access” for permissions, which gives the key the ability to perform all the necessary email sending functions., and then paste it in a secure document so that you can use it later. If you lose your key, you will need to generate a brand new one. Once you have saved your key, you can click the “Done” button.
Creating a Python Environment
Now we are ready to see how to send an email in the context of a Flask application. We’ll begin by making a new directory on your computer called *twilio-sendgrid-tests* or similar, then creating a new Python virtual environment in it.
For Mac and Unix users, the commands are:
$ mkdir twilio-sendgrid-tests $ cd twilio-sendgrid-tests $ python3 -m venv venv $ source venv/bin/activate (venv) $ _
For Windows users, the commands are:
$ mkdir twilio-sendgrid-tests $ cd twilio-sendgrid-tests $ python -m venv venv $ venv\Scripts\activate (venv) $ _
Next, install Flask, Flask-Mail and python-dotenv in your virtual environment:
(venv) $ pip install flask flask-mail python-dotenv
Creating a Flask Application
Let’s create a starter Flask and Flask-Mail application in file app.py:
import os from flask import Flask, render_template, request, redirect, url_for, flash from flask_mail import Mail, Message app = Flask(__name__) app.config['SECRET_KEY'] = 'top-secret!' app.config['MAIL_SERVER'] = 'smtp.sendgrid.net' app.config['MAIL_PORT'] = 587 app.config['MAIL_USE_TLS'] = True app.config['MAIL_USERNAME'] = 'apikey' app.config['MAIL_PASSWORD'] = os.environ.get('SENDGRID_API_KEY') app.config['MAIL_DEFAULT_SENDER'] = os.environ.get('MAIL_DEFAULT_SENDER') mail = Mail(app)
Here you can see how to properly configure Flask-Mail to use SendGrid’s SMTP service. The important settings are:
- The mail server should be
smtp.sendgrid.net.
- The mail port should be 587 (port 25 is also supported, if you prefer)
- TLS must be enabled
- Authentication is required. For the username you must use
apikey(this is the same for all SendGrid accounts). The password is the SendGrid API key that you created earlier.
For this Flask application I added the above settings in the proper configuration keys for the Flask-Mail extension. For security reasons I am importing the API key from an environment variable named
SENDGRID_API_KEY. I’m also setting a default sender email address from an environment variable. This is the email address that will appear in the “from” field of all emails by default.
Create a .env file with the two required variables:
SENDGRID_API_KEY=”<your-sendgrid-api-key>” MAIL_DEFAULT_SENDER=”<your-sender-email-address>”
Flask will automatically import the variables defined in the .env file (as long as you have the python-dotenv package installed), so this is enough to get these two variables into the Flask application configuration.
Sending an Email
Let’s see how you can send yourself a test email from the Python shell:
(venv) $ flask shell
Note that I started the Python shell with the
flask shell command, as this will ensure that the Flask application we created in app.py is imported.
Once in the shell, import the
Message class from Flask-Mail:
from app import mail from flask_mail import Message
Next create a
Message instance:
msg = Message('Twilio SendGrid Test Email', recipients=['recipient@example.com']) msg.body = 'This is a test email!' msg.html = '<p>This is a test email!</p>'
The last step is to send this email:
mail.send(msg)
And that’s it! If everything goes well, the email should arrive at your inbox a few seconds later.
If you want to see a Flask route example that integrates this functionality, here is a simple one you can add at the bottom of app.py:
@app.route('/', methods=['GET', 'POST']) def index(): if request.method == 'POST': recipient = request.form['recipient'] msg = Message('Twilio SendGrid Test Email', recipients=[recipient]) msg.body = ('Congratulations! You have sent a test email with ' 'Twilio SendGrid!') msg.html = ('<h1>Twilio SendGrid Test Email</h1>' '<p>Congratulations! You have sent a test email with ' '<b>Twilio SendGrid</b>!</p>') mail.send(msg) flash(f'A test message was sent to {recipient}.') return redirect(url_for('index')) return render_template('index.html')
To complete the example application, you need to add the index.html template file. First create a directory for your templates:
(venv) $ mkdir templates
And then write the following content in file templates/index.html:
<!doctype html> <html> <head> <title>Twilio SendGrid Example</title> </head> <body> <h1>Twilio SendGrid Example</h1> {% with messages = get_flashed_messages() %} {% for message in messages %} <p>{{ message }}</p> {% endfor %} {% endwith %} <form action="" method="post"> <p>Your email: <input type="text" name="recipient"></p> <p><input type="submit" value="Send a Test Email"></p> </form> </body> </html>
Run the test application with:
(venv) $ flask run
Then navigate to in your web browser to access the application.
You can now enter a recipient email address and when you click the button a test email will be sent to that address.
The complete Flask example application is available on GitHub if you prefer to download it:.
If Your Emails Aren’t Delivered
My hope is that using the Flask application above you are successful in sending emails. There is a chance, however, that your emails will fail to be delivered. when you try to send an email as shown in the previous section, I accidentally sent to an example.com address failed to be delivered. For any emails that were not delivered, you can click on the email to see detailed information, including any error responses sent by the recipient’s email server.
Conclusion
Twilio SendGrid is an extremely simple service that integrates nicely into the standard Flask email sending workflow based on the Flask-Mail extension.
I hope you decide to give Twilio SendGrid a try. If you want to learn more about this service in a fun way, download the TwilioQuest game and follow the SendGrid mission!
Miguel Grinberg is a Python Developer for Technical Content at Twilio. Reach out to him at mgrinberg [at] twilio.com if you have a cool Python project you’d like to share on the Twilio blog! | https://www.twilio.com/blog/using-twilio-sendgrid-to-send-emails-from-python-flask-applications | CC-MAIN-2022-05 | refinedweb | 1,178 | 55.34 |
I’m fairly new to FMOD and have run in to a problem and I’m not really sure why. I’m working on an audio options menu for a student project and am having trouble getting the ‘universal’ volume control working correctly. For some reason, the channels aren’t correctly storing the channel group information. My current set up works like this:
[list=1:2sbwgt5f]
[:2sbwgt5f]My Initialize() function inits FMOD and creates 2 channel groups ("SFX" and "MUSIC") and adds them to the master group (all return FMOD_OK).
[/:m:2sbwgt5f]
[:2sbwgt5f]I have a structure that holds a Channel and a Sound*. LoadSound() function creates a new structure, creates a stream, and adds my channels to the proper channel group. The structure that that data is stored in is then pushed back in to a vector. The channel stores the correct channel group through this point.
[/:m:2sbwgt5f]
[:2sbwgt5f]PlaySound() just plays the sound.[/*:m:2sbwgt5f][/list:o:2sbwgt5f]
For some reason, when I call PlaySound(), the channel group is no longer set to the group that I set it to in LoadSound(). It is being reset to "FMOD master group." All of my setChannelGroup() calls are returning FMOD_OK, so I’m not sure what the problem is. As I mentioned, I’m pretty new to FMOD so it’s probably some small thing I’m missing. Thanks in advance for the help.
- Dimidium asked 8 years ago
- You must login to post comments
Based on the order you are doing things I suspect you’re setting the channelgroup for an invalid channel handle. If you’re calling System::playsound after setChannelGroup that will create a new channel overwriting the old one. An (FMOD::Channel*) is really just a handle. Before you call playSound everything you do with the channel should return FMOD_ERR_INVALIDHANDLE error. You can call System::playSound in the LoadSound function so that you have a valid handle (you can use the ‘paused’ parameter to stop it from playing immediately). Then you will have a valid handle and your PlaySound function can just call channel->setPaused(false).
Hope this helps.
-Pete
- Guest answered 8 years ago
Thanks for the reply Pete. Originally, I was having that problem with FMOD_ERR_INVALIDHANDLE when I first started implementing channel groups, but I fixed that. I forgot to mention in my original post that I call playSound() in my LoadSound() function. When I step through the process in the debugger, everything returns FMOD_OK. Currently, my project only uses 2D sounds. More specifically, here is a slightly dumbed down version of what’s going on:
[code:udx95dc2]
void Initialize()
{
m_Result = FMOD::System_Create(&m_pSystem);
m_pSystem->init(128, FMOD_INIT_NORMAL, 0); // Create channel groups and add to master group m_Result = m_pSystem->createChannelGroup("SFX", &m_pSFXGroup); m_Result = m_pSystem->createChannelGroup("Music", &m_pMusicGroup); m_Result = m_pSystem->getMasterChannelGroup(&m_pMasterGroup); m_Result = m_pMasterGroup->addGroup(m_pSFXGroup); m_Result = m_pMasterGroup->addGroup(m_pMusicGroup); m_bIsInitialized = true;
}
int LoadSound(const char* szFileName, const unsigned int nChannelGroup)
{
// TSound is a structure containing a Sound* and Channel*
m_tSound = new TSound();
m_Result = m_pSystem->createStream(szFileName, FMOD_DEFAULT, 0, &m_tSound->m_Sound); m_pSystem->playSound(FMOD_CHANNEL_FREE, m_tSound->m_Sound, true, &m_tSound->m_Channel); switch(nChannelGroup) { case CHANNEL_SFX: m_Result = m_tSound->m_Channel->setChannelGroup(m_pSFXGroup); break; case CHANNEL_MUSIC: m_Result = m_tSound->m_Channel->setChannelGroup(m_pMusicGroup); break; default: break; } // If I call getChannelGroup() on the channel at this point, it correctly returns either SFX or MUSIC. // m_vSoundsList is a vector of TSounds m_vSoundsList.push_back(m_tSound); m_tSound = NULL; // Return the sound's position in the vector. return (int)m_vSoundsList.size() - 1;
}
void PlaySound(const int nSoundID)
{
// When it gets to this point, if I call getChannelGroup() on the sound
// being passed in the group is set to FMOD master group
m_Result = m_pSystem->playSound(FMOD_CHANNEL_FREE,
m_vSoundsList[nSoundID]->m_Sound, false, &m_vSoundsList[nSoundID]->m_Channel);
}
[/code:udx95dc2]
What’s happening is I call setVolume on the channel group which correctly sets the group’s volume, however since the channel’s group is being changed to FMOD master group, it is not receiving the changes. The only reason I can think of is that the channel is falling out of scope when I exit LoadSound() so everything is resetting back to default values. So, besides the sloppy code, does anything stand out to you? 😛
You’re playing your sound twice. When you call m_pSystem->playSound() in your LoadSound() function, you’re playing one instance of that sound, and attaching it to the appropriate ChannelGroup. Later, in your PlaySound() function, you’re calling m_pSystem->playSound() again, which plays a new instance of that sound.
That new instance of the sound doesn’t know about the existence of the old instance of the sound. Any settings that you changed on the instance that you created in LoadSound() don’t apply to the instance that you create in PlaySound().
You have two choices: you can either do the ChannelGroup manipulation in PlaySound() for each channel that you play (and remove it from the LoadSound() function), or you can call Channel::setPaused(…, false) in PlaySound() to unpause the sound that you started in LoadSound().
I suspect that you’ll end up with fewer problems overall if you use the former (setting the ChannelGroup in PlaySound() and not playing in Loadsound()) than the latter.
Hope that helps!
- Adiss answered 8 years ago
Thank you! I removed the playSound() from LoadSound() and now everything works great. I didn’t realize that calling playSound() multiple times would mess with my settings. | http://www.fmod.org/questions/question/forum-32072/ | CC-MAIN-2017-26 | refinedweb | 894 | 52.39 |
python def cube(number): return number * number * number def by_three(number): if cube(number) % 3 == 0: return number else: return False by_three(3) It should return 27, but instead returns 3.
Practice makes perfect (Needs Debug)
overcantor #2
You need to call your cube function.
is this not it? This is what the lesson said to do.
overcantor #4
You have called your by_three method in your last line, but you have not called your cube method anywhere.
However, In the previous lesson, it specifically told me how to do this:
overcantor #6
I am not sure you understand what “calling a function” means.
Calling the cube function on the by three function returns 27, but the lesson won’t accept that.
I see what your problem is. Basically, you are not calling “cube”, as “overcantor” mentioned in your “by_three” function. The code should read something like:
def by_three(number):
if cube(number) % 3 == 0:
return cube(number)
else:
return False | https://discuss.codecademy.com/t/practice-makes-perfect-needs-debug/194728 | CC-MAIN-2018-39 | refinedweb | 161 | 72.87 |
0
I decided to learn C++ STL and I was exprimenting with STL containers.
I saw this example here:
// inserting into a vector #include <iostream> #include <vector> using namespace std; int main () { vector<int> myvector (3,100); vector<int>::iterator it; it = myvector.begin(); it = myvector.insert ( it , 200 ); myvector.insert (it,2,300); // "it" no longer valid, get a new one: it = myvector.begin(); vector<int> anothervector (2,400); myvector.insert (it+2,anothervector.begin(),anothervector.end()); int myarray [] = { 501,502,503 }; myvector.insert (myvector.begin(), myarray, myarray+3); cout << "myvector contains:"; for (it=myvector.begin(); it<myvector.end(); it++) cout << " " << *it; cout << endl; return 0; }
My question is why did they add 2 to it in the line
myvector.insert (it+2,anothervector.begin(),anothervector.end());?. At first I thought it was because they inserted 2 items
myvector.insert (it,2,300); but they later update it again
it = myvector.begin(); so it is not because of that.
The constructor for the function is
void insert ( iterator position, InputIterator first, InputIterator last );
Is the position supposed to be location of the vector in which something is being inserted or something else?
Edited 4 Years Ago by sergent: Additional info | https://www.daniweb.com/programming/software-development/threads/419071/vector-iterators | CC-MAIN-2017-04 | refinedweb | 201 | 51.14 |
This is part of a series I started in March 2008 - you may want to go back and look at older parts if you're new to this series.
One of the big elephants sauntering around the room for a long time has been
the issue of how to handle the specifics of how Ruby handles
nil,
true and
false. To a lesser extent this issue also affects numbers, but it is those
three values that are most critical right now.
The reason is control flow. So far, we've treated these values the way C does:
nil is simply the null pointer;
true is any non-zero value, and false is zero
(and thus for most practical intents the same as
nil.
The problem, of course, is that this is not the way it is in Ruby.
true,
false
and
nil are values distinct from the numbers, and they compare with each others
and with other values in different ways than in C.
They are also objects. Which means we lose out on some of the simplest ways of
doing comparisons and turning the comparison results into a value. We may find
people doing things like
if <some expression>.nil?.
nil and
false both evaluate to false in a conditional, but
nil != false.
So far "faking it" have worked, because with a few exceptions like the ones above, the C and Ruby variations are relatively compatible. But it's not a lasting solution.
There is another problem: If we change basic contructs like the s-expression
if to
work on Ruby objects, we'll find it hard to implement the "plumbing" under Ruby.
Don't bring out the pickaxe just yet (groan). As it happens, our compiler compiles two very different languages: The s-expression inspired low level language used both as the compilation target for Ruby and implementation language for low level features, and Ruby itself.
The former language is de facto typeless, like BCPL: We pass values around with wild abandon, and we even clobber Ruby local variables and instance variables with it, but what meaning these values have depends entirely on usage rather than the type of the variable (as in C) or a type attached to the value itself, like in Ruby.
And as it happens, here lies both the problem and solution to our conundrum from above:
If only the compiler can know when it is dealing with real Ruby values, and when
it is dealing with something else, then, e.g.
compile_if can generate different
code in these situations.
Not only that: We will need this information when we eventually get tired of leaking memory and start adding a garbage collector - otherwise we're stuck with a conservative collector, so we get twice the benefit.
It will also help us contain the "leakage" of untyped values into Ruby, by letting us define and narrow the rules for when and where and how we're allowed to work with them.
As it happens, we don't need a very complicated type-system: For now we can get away with knowing if a reasonable subset of constructs returns either an object or may contain anything.
That's it. That's the grand total of the static typing we'll introduce this time.
However the changes start laying the groundwork for more static typing that we can use for optimizations and sanity checks. Ultimately I wish to relegate the "s-expression plumbing" to a very restricted space.
Apart from just categorizing stuff into two types, there's another limitation too
for now: Where we act on type information, we will treat all variables as typed to
objects, and all return variables from method calls to be typed as objects. We
will implicitly assume that the s-expression syntax will be contained, though we
are not yet verifying that. In some cases this will be outright wrong. E.g. this
explicitly prevents
if foo; bar; end from working correctly if
foo is not an
object, and happens to contain 0, and in any number of similar instances, so it
is likely introducing some regressions (I caught one while writing this - there are
probably more).
First, let's put some basic test cases in place. You'll find them in d22b95f
Then lets start putting our new typing into place. Let's start with a
Value class
to hold a possibly typed value (in 3ec81cb):
require 'delegate' # Used to hold a possiby-typed value # Currently, valid values for "type" # are :object or nil. class Value < SimpleDelegator attr_reader :type def initialize ob, type = nil super(ob) @type = type end # Evil. Since we explicitly check for Symbol some places def is_a?(ob) __getobj__.is_a?(ob) end end
To simplify refactoring, we have it be a delegator, so we only selectively add/change
behaviour as needed. For now, the only new thing is that
#type will return the associated
type tag, or nil. We only support
:object for now, to indicate we know the value to be a
pointer to a Ruby object.
I'm not going to go through ever detail of the changes in
compiler.rb. You can find the full set
in 0ded9c1
Apart from a number of changes to return objects of the new
Value class, the main things
to notice are as follows:
We add
:false,
:true, and
:nil to
@global_constants to prevent them from being treated
as method calls:
+ @global_constants << :false + @global_constants << :true + @global_constants << :nil
Next up is this change in
compile_if:
- @e.jmp_on_false(l_else_arm, res) + + if res && res.type == :object + @e.save_result(res) + @e.cmpl(@e.result_value, "nil") + @e.je(l_else_arm) + @e.cmpl(@e.result_value, "false") + @e.je(l_else_arm) + else + @e.jmp_on_false(l_else_arm, res) + end +
What's happening here is that instead of assuming an untyped value, we check to see if we know we have an object. If we do, and we come across "if result; ...; else ...; end", we change the code to effectively do the equivalent of:
if result != nil && result != false # if block else # else block end
There's an equivalent change for
compile_while.
Furthermore there's a few minor additional changes to
scope.rb to prevent true/false/nil from
being treated as method calls in 52f31ad3
We also need to check in
transform.rb that we're not trying to treat true, false and nil as
local variables. See f2af5fc
In order to make these changes work, we also need to modify the runtime in various ways.
Most obviously, we need to actually make
true,
false and
nil real objects. We do that in
lib/core/core.rb:
+require 'core/true' +true = TrueClass.new # FIXME: MRI does not allow creating an object of TrueClass +require 'core/false' +false = FalseClass.new # FIXME: MRI does not allow creating an object of FalseClass +require 'core/nil' +nil = NilClass.new # FIXME: MRI does not allow creating an object of NilClass. + # OK, so perhaps this is a bit ugly... self = Object.new @@ -59,9 +66,6 @@ STDERR = 1 STDOUT = IO.new ARGV=7 Enumerable=8 #Here because modules doesn't work yet -nil = 0 # FIXME: Should be an object of NilClass -true = 1 # FIXME: Should be an object of TrueClass -false = 0 # FIXME: Should be an object of FalseClass
These depends on very basic initial implementations of
TrueClass,
FalseClass and
NilClass - see c356591
Another change is in
lib/core/fixnum.rb, where all the comparison operators needs to change:
def == other - %s(eq @value (callm other __get_raw)) + %s(if (eq @value (callm other __get_raw)) true false) end
This is because
%s(eq ..) etc. does not handle typing yet (and they may not necessarily
ever need it), so we use our newly
typed %s(if ..) coupled with explicitly returning the
right objects instead of the numeric values we'd previously get.
It is important to do this in particular as one of the changes I snuck past in
compiler.rb
assumes that method calls returns Ruby objects.
Almost done now, but there's also a minor change to
lib/core/object.rb to remove the horribly
hacky
true and
false methods we used previously.
As it happens, we have a few more things to do:
%s(and ..) and
%s(or ...) needs to take
type information into account to be able to generate proper code for e.g.:
if a and b ... elsif a or c ... end
In our new world,
a and b (or
a && b) will always be true, because both
true and
false
have integer values that are non-null. Similarly
a or c /
a || c will always be true as well,
since both values will be seen to evaluate to true.
First of all, I've added a test case to catch this, in 1dfe043. But one of our other test
cases shows a regression as well.
features/inputs/strcmp.rb now gives wrong results, because
we previously relied on being able to use "plain Ruby"
if to check the result of a call to
strcmp that we stored in a local variable. But for now at least, we're assuming variables
contain objects. We'll likely want to refine that, but for now we'll apply a workaround that
will work (in 32ddcde):
%s(assign res (if (strcmp @buffer (callm other __get_raw)) false true))
By explicitly assigning with the values
false or
true, from the result of a value that
will get an indeterminate type, it will work again.
But lets fix "&&"/"and". Firstly we need to actually store the return value from
compile_eval_arg
for
if_arm and
else_arm (in 2ae727d):
- compile_eval_arg(scope, if_arm) + ifret = compile_eval_arg(scope, if_arm) @e.jmp(l_end_if_arm) if else_arm @e.local(l_else_arm) - compile_eval_arg(scope, else_arm) if else_arm + elseret = compile_eval_arg(scope, else_arm) if else_arm
Secondly, we need to determine type based on them. Most importantly, we can only
safely return a type that is shared by both of them if both
if and
else are
present (also in 2ae727d):
- return Value.new([:subexpr]) + # We only return a specific type if there's either only an "if" + # expression, or both the "if" and "else" expressions have the + # same type. + # + type = nil + if ifret && (!elseret || ifret.type == elseret.type) + type = ifret.type + end + + return Value.new([:subexpr], type) end
Other than that, we're simply just adding our missing
compile_or:
(EDIT: This implementation is broken; a correct version will be in part 41)
+ def compile_or scope, left, right + compile_if(scope, left, false, right) + end
And that's it for this time. | https://hokstad.com/compiler/39-to-be-or-not-to-be-nil | CC-MAIN-2021-21 | refinedweb | 1,740 | 69.92 |
pip install pg8000
The Python pg8000 library is among the top 100 Python libraries, with more than 15,737,826 downloads. This article will show you everything you need to get this installed in your Python environment.
How to Install pg8000 on Windows?
- Type
"cmd"in the search bar and hit
Enterto open the command line.
- Type “
pip install pg8000” (without quotes) in the command line and hit
Enteragain. This installs pg8000 for your default Python installation.
- The previous command may not work if you have both Python versions 2 and 3 on your computer. In this case, try
"pip3 install pg8000"or “
python -m pip install pg8000“.
- Wait for the installation to terminate successfully. It is now installed on your Windows machine.
Here’s how to open the command line on a (German) Windows machine:
First, try the following command to install pg8000 on your system:
pip install pg8000
Second, if this leads to an error message, try this command to install pg8000 on your system:
pip3 install pg8000
Third, if both do not work, use the following long-form command:
python -m pip install pg8000 pg8000 on Linux?
You can install pg8000 on Linux in four steps:
- Open your Linux terminal or shell
- Type “
pip install pg8000” (without quotes), hit Enter.
- If it doesn’t work, try
"pip3 install pg8000"or “
python -m pip install pg8000“.
- Wait for the installation to terminate successfully.
The package is now installed on your Linux operating system.
How to Install pg8000 on macOS?
Similarly, you can install pg8000 on macOS in four steps:
- Open your macOS terminal.
- Type “
pip install pg8000” without quotes and hit
Enter.
- If it doesn’t work, try
"pip3 install pg8000"or “
python -m pip install pg8000“.
- Wait for the installation to terminate successfully.
The package is now installed on your macOS.
How to Install pg8000 in PyCharm?
Given a PyCharm project. How to install the pg8000
"pg8000"without quotes, and click
Install Package.
- Wait for the installation to terminate and close all pop-ups.
Here’s the general package installation process as a short animated video—it works analogously for pg8000 if you type in “pg8000” in the search field instead:
Make sure to select only “pg8000” because there may be other packages that are not required but also contain the same term (false positives):
How to Install pg8000 in a Jupyter Notebook?
To install any package in a Jupyter notebook, you can prefix the
!pip install my_package statement with the exclamation mark
"!". This works for the pg8000 library too:
!pip install my_package
This automatically installs the pg8000 library when the cell is first executed.
How to Resolve ModuleNotFoundError: No module named ‘pg8000’?
Say you try to import the pg8000 package into your Python script without installing it first:
import pg8000 # ... ModuleNotFoundError: No module named 'pg8000'
Because you haven’t installed the package, Python raises a
ModuleNotFoundError: No module named 'pg8000'.
To fix the error, install the pg8000 library using “
pip install pg8000” or “
pip3 install pg8000” in your operating system’s shell or terminal first.
See above for the different ways to install pg8000. | https://blog.finxter.com/how-to-install-pg8000-in-python/ | CC-MAIN-2022-33 | refinedweb | 518 | 65.42 |
Article information
Article relates to
Telerik JustMock
Created by
Kaloyan, Telerik
Last modified
12/17/2012
Last modified by
Even though JustMock goes nicely with the most automated
build servers (or Continuous Integration Servers), sometimes it can be tricky.
This article answers some of the most frequently asked
questions.
Q: Do I need to install
JustMock on the build machine?
A: When JustMock runs in
elevated mode it operates as a .NET profiler so it can overwrite IL code at
runtime. To configure profilers like this for .NET Framework v2.0/v3.0/v3.5, Microsoft
requires registration of the profiler as a COM component. The COR_PROFILER
environment variable is the GUID for the JustMock COM component(more information could be found here). For .NET
Framework v4.0/v4.5 you can take advantage of COR_PROFILER_PATH environment
variable(described here). We strongly recommend installing JustMock on the build server,
because the installation takes care for COM registration itself.
If installing JustMock on
the build machine can not be done, another option is to register the
Telerik.CodeWeaver.DLL manually for both 32 and 64bits modes. You can use
regsvr32.exe tool to accomplish this.
Q: Do I need to have Visual
Studio installed on the build machine?
A: Visual Studio is not required by JustMcok on the build machine. If you are using MSTest for a test framework
in your project, please refer to the Microsoft documentation for build server dependencies, but in short, MSTest requiers Visual Studio on your build server.
Q: My tests are failing with
exception:
"The type or namespace name 'Telerik'
could not be found (are you missing a using directive or an assembly
reference?”
A: While, it is recommended to put the JustMock assemblies(JustMock.DLL and
CodeWeaver.Api.DLL) into the Global Assembly Cache(GAC), is not required. If you choose not to place the assemblies in the GAC, make sure
that you have the DLLs correctly referenced and in the correct folder.
Q: My tests are failing with
exception:
"Type 'Telerik.JustMock.MockException' in
assembly 'Telerik.JustMock, Version= 2012.3
1016, Culture=neutral, PublicKeyToken=8b221631f7271365' is not marked as serializable.”
A: The main problem here is
that the Telerik.CodeWeaver.Api.DLL assembly that is referenced by JustMock is not found with the project binaries, causing the MockException is thrown. To fix this, ensure that the Telerik.CodeWeaver.Api.DLL assembly is copied to the correct binaries folder. You can also use the “Workspace” tab to specify what other
files (not in your project) to be copied to the build directory.
“Any exception concerning
that the profiler is not enabled”
A: This exception will only be thrown if you are using the elevated features of JustMock in
your tests. There are several known reasons that can cause this exception:
Q: Sometimes there are
failing tests on the server side when everything has passed on the local
machine. What is the reason and what could be done about this?
A: If you are using the
elevated features of JustMock in your test project, the reason for tests to
fail could be the order of their execution. The JIT Compilation of a certain
class under test before its mocked instance will lead to throwing of an
exception inside the test method using this mocked object and accordingly to
the failure of the test.
We know that the execution
order should not affect the test results by any mean. For this, we recommend
the splitting of the tests in two different assemblies. One for the tests using
the profiler(elevated tests) and another one for the rest.
Q: Where can I find more
information about integrating JustMock with other 3rd party tools?
A: You can check our online help documentation
for articles, concerning JustMock integration with other 3rd
party software. Also, you could try searching for something more specific in our
forum where you could find a pinned article with the latest online resources. And finally don`t forget to look in our Just*Team blogposts.
Resources
Buy
Try | https://www.telerik.com/support/kb/justmock/details/integrating-justmock-on-build-machines | CC-MAIN-2019-22 | refinedweb | 673 | 65.83 |
If you are a veteran ASP/ADO developer who has not tested the .NET waters, you'd better get started soon. To give you a taste of .NET, we're going to connect a Microsoft Access database (you can use a SQL Server or Oracle database instead) to the Internet and then retrieve and display some data. The example requires both Information Internet Services (IIS) and the .NET framework. You can download the .NET Framework here. If you want to try a free ASP.NET development environment, download Web Matrix.
An introduction to server controls
Active Server Pages (ASP) was one of the first Microsoft Web technologies for connecting a database and the Web. ASP.NET is a complete rewrite of that classic language. You can still use both, because .NET pages use an .aspx extension. (ASP files keep their .asp extension.)
Much of the code you write in ASP.NET will be executed on the Web server and will return only HTML to the client. Fortunately, .NET provides you with many new controls that are similar to standard HTML controls, such as drop-down lists and text boxes. Table A lists the most common server controls.
Table A
.NET server controls have the advantage of being created on the Web server as opposed to being created within the page like HTML. As a result, they're available for processing before being sent to the client. For example, you can validate content within the page or on the server side. That means you can validate content within the page and then revalidate content on the server side.
For the most part, you can create a .NET control simply by adding this component:
runat="server"
to the corresponding HTML element using this syntax:
<asp:control_name
Some development tools are even easier to use. For instance, Visual Studio .NET lets you create a server control by dragging and dropping the control on a Web page.
In addition to the standard server-side HTML controls, ASP.NET offers a set of validation controls:
- RequiredFieldValidation requires a value.
- CompareValidator compares the values in two controls, such as validating e-mail addresses where the user is required to enter an e-mail address twice.
- RangeValidator determines that the entry falls within a set range.
- RegularExpressionValidator validates control entries using regular expressions.
- CustomValidator lets you write your own validation code.
- Validation Summary displays a list showing all the validation currently being used within a page.
Using ADO.NET
You're probably familiar with ADO, but ADO.NET is an altogether new language. But don't let that intimidate you—there's enough similarity so that learning how to use the new objects isn't that difficult. Connecting to a database is a three-step process:
- Import a .NET namespace to establish a connection.
- Create an ADO.NET DataReader object to grab data.
- Create an ADO.NET Repeater object to display data.
The namespace is new to .NET, so there's really no ADO counterpart. ADO connections are made via provider strings and a Connection or Command object. The DataReader is the ADO Recordset counterpart, and the Repeater is a server control that is used to display the data based on a template.
Creating an ADO.NET connection
To retrieve data from your database, you'll need ADO.NET. If you're familiar with IIS and the Web folder hierarchy, you probably don't need any help setting up an example. You can follow ours by copying Northwind (the sample database that comes with Access) to the Inetpub\wwwroot folder on your local system. Our example is in a Web folder named nettest. Cut and paste (or enter) the code example into a text editor and save it as nettest.aspx.
Now, import the .NET namespace that allows you to work with OLEDB databases:
<%@ Import Namespace="System.Data.OleDb" %>
The PageLoad event executes the code that connects to the Northwind database, and Server.mappath returns the physical path to the folder that contains it, as shown in Listing A.
Connection strings
If you wanted to connect to SQL Server using an OLEDB connection, you could use the following:
"Provider=sqloledb;Data Source=Martin;Initial Catalog=NorthWind;Integrated Security=SSPI;"
If you're working with Oracle, you could use:
"Provider=msdaora;Data Source=OracleDataBase;User Id=YourUserName;Password=YourPassword;"
A useful resource for connection information is connectionstrings.com, which contains a connection string for every situation imaginable.
Creating the ADO.NET objects
The next step is to create a DataReader object to hold the data you want to display. The following code uses the Command object's ExecuteReader method to create a DataReader object that will store all the records from the Northwind Customers table:
cnn.Open()
sql="SELECT CompanyName, ContactName, Address, City FROM Customers"
cnn=New OleDbCommand(sql,cnn)
dbread=cnn.ExecuteReader()
This code opens the connection and defines the data-retrieving SQL statement. Then the ExecuteReader method creates the DataReader object (dbread). Note that OleDbCommand passes both the connection and the SQL statement. The DataReader control then returns a stream of read-only data to the client.
Using a Repeater control to display the data
Now you can use a Repeater control to display the data by binding the DataReader object. The Repeater control lets you construct a simple template (for example, an HTML table) that's repeated for each row of data returned by the query.
Use a HeaderTemplate block to create the initial table structure; the data will appear within the ItemTemplate (table rows and columns) block. For example, the code below creates a table header for our customer data that refers to the fields returned by the earlier SQL statement:
<HeaderTemplate>
<table border="1" width="100%">
<tr>
<th>CompanyName</th>
<th>ContactName</th>
<th>Address</th>
<th>City</th>
</tr>
</HeaderTemplate>
Unlike other ASP.NET objects, the Repeater has no layout or styles available; you must define your own. Each row returned is displayed by the ItemTemplate block. The following script contains one cell (in the HTML table) for each field:
<ItemTemplate>
<tr>
<td><%#Container.DataItem("CompaName")%></td>
<td><%#Container.DataItem("ContactName")%></td>
<td><%#Container.DataItem("Address")%></td>
<td><%#Container.DataItem("City")%></td>
</tr>
</ItemTemplate>
You can't tell from the above example, but the template code is within the HTML body tags but outside the script definition.
Viewing the .NET page
The code in Listing B displays the customer data within the browser using an HTML table template to display the items.
Cut and paste this script into a text editor and be sure to save it with the .aspx extension. Then save or move the .aspx file to the Web root folder (wwwroot\nettest, for this example). Launch your browser and enter the appropriate address to open this file. When viewed in the browser (Figure A), the file displays a simple HTML Web page and the requested data, as defined by the SQL statement query.
You can also improve the look of the page. For example, you can alternate row colors by adding another template section. Specifically, the AlternatingItemTemplate block changes the background color of each table cell. The following script changes the cell background to yellow (FFFF00):
<AlternatingItemTemplate>
<tr bgcolor="#FFFF00">
<td><%#Container.DataItem("companyname")%></td>
<td><%#Container.DataItem("contactname")%></td>
<td><%#Container.DataItem("address")%></td>
<td><%#Container.DataItem("city")%></td>
<td><%#Container.DataItem("Region")%></td>
</tr>
</AlternatingItemTemplate>
To affect every other row, place the AlternatingItemTemplate block after the ItemTemplate block.
Conclusion
.NET isn't exactly new on the scene. But if you have delayed making the leap from classic ASP to ASP.NET, now's the time to get started. If you have some solid experience with ASP and ADO, you should be able to make the transition fairly easily.
Full Bio
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals. | http://www.techrepublic.com/article/creating-your-first-web-page-with-aspnet/1052980/ | CC-MAIN-2017-13 | refinedweb | 1,322 | 58.08 |
howdy folks just one quick question here I put this simple function together and I everytime I try executing it I get some funky message saying unresolved external check it out
so where is the problem here.so where is the problem here.Code:
#include <iostream.h>
#include <ctype.h>
triangle(float a, float b);
void main()
{
float a,b;
float area;
cout<<char(22);
cout<<"Enter the length of the base of the triangle: "; cin>>a;
cout<<"Now enter the height: "; cin>>b;
triangle(a, b);
}
void triangle(float a, float b)
{
float area;
area = .5 * a * b;
cout<<"The area of the triangle is: "<<area;
} | http://cboard.cprogramming.com/cplusplus-programming/56475-function-help-printable-thread.html | CC-MAIN-2014-15 | refinedweb | 107 | 72.87 |
Write the documentation for a class or namespace. The documentation is parsed by TDocParser and then passed to TClassDocOutput to generate the class doc header, the class description, members overview, and method documentation. All generic output functionality is in TDocOutput; it is re-used in this derived class. You usually do not use this class yourself; it is invoked indirectly by THtml. Customization of the output should happen via the interfaces defined by THtml.
Create HTML files for a single class.
This function builds the class charts for one class in GraphViz/Dot format, i.e. the inheritance diagram, the include dependencies, and the library dependency. Input: out - output file stream
This function builds the class tree for one class in HTML (inherited and succeeding classes, called recursively) Input: out - output file stream classPtr - pointer to the class dir - direction to traverse tree: up, down or both
It makes a graphical class tree Input: psCanvas - pointer to the current canvas classPtr - pointer to the class
Build the class tree for one class in GraphViz/Dot format Input: filename - output dot file incl. path
Build the class tree of inherited members for one class in GraphViz/Dot format Input: filename - output dot file incl. path
Build the include dependency graph for one class in GraphViz/Dot format Input: filename - output dot file incl. path
Build the library dependency graph for one class in GraphViz/Dot format Input: filename - output dot file incl. path
Create the hierarchical class list part for the current class's base classes. docFileName contains doc for fCurrentClass.
Create a hierarchical class list The algorithm descends from the base classes and branches into all derived classes. Mixing classes are displayed several times.
Descend hierarchy recursively loop over all classes and look for classes with base class basePtr
Create an output file with a graphical representation of the class inheritance. If force, replace existing output file. This routine does nothing if fHtml->HaveDot() is true - use ClassDotCharts() instead!
Called by TDocParser::LocateMethods(), this hook writes out the class description found by TDocParser. It's even called if none is found, i.e. if the first method has occurred before a class description is found, so missing class descriptions can be handled. For HTML, its creates the description block, the list of functions and data members, and the inheritance tree or, if Graphviz's dot is found, the class charts. | http://root.cern.ch/root/html520/TClassDocOutput.html | crawl-003 | refinedweb | 400 | 54.42 |
#include <EBIndexSpace.H>
Construction of the EBIndexSpace can follow one of methods 1. From a previously written out HDF5 file. This is a representation of the EBIndexSpace at the finest level. When this is read back into a running application the EBIndexSpace at the coarser levels is regenerated on construction 2. As a GeometryService. The base class for Geometry objects. 3. As a Workshop object that reads the finest level EB boxes from the EBIndexSpace itself and fills in the data structure as it accepts it. 4. As a Worshop object that has an already defined data decomposition
If a_ncellMax is set, that is the max width of an internal grid. Otherwise use defaults of (16 in 3D, 64 in 2d)
This
reads in all levels from finest level down
defines from one level and then does coarsening.
Get the total of the volume fractions over the entire domain. This is blocking as a broadcast and gather are required.
return level index of domain. return -1 if a_domain does not correspond to any refinement of EBIS.
Referenced by getCoveredGrids(), getFlowGrids(), getGrids(), getIrregGrids(), getOrigin(), irregCells(), and levelGrids().
Referenced by getBox(), getCoveredGrids(), getFlowGrids(), and getIrregGrids(). | http://davis.lbl.gov/Manuals/CHOMBO-RELEASE-3.3/classEBIndexSpace.html | CC-MAIN-2018-34 | refinedweb | 193 | 58.48 |
get it working.
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Thankfully the JSDoc project has been picked up (correct me if I'm wrong) and how supported entirely in JavaScript (via Rhino) as the JsDoc ToolKit.
With a small change (or not depending on your code) to the
extend method, all the documentation generates perfectly.
For example, this is how my object would be normally laid out and documented:
/** * @fileoverview Definition of cat * @author Remy Sharp (actually pinched from Dean Edwards) */ var Cat = Animal.extend({ /** * @constructor * Cats like to meow when they're made */ constructor: function () { this.base(); this.say("Meow"); } /** * Our cat only eats mice * @param {Mouse} food Food fed to the cat */ eat: function (food) { if (food instanceof Mouse) this.base(); else this.say("Yuk! I only eat mice."); } });
Making the following changes sorts out the JsDoc Toolkit parser and allows everything to be documented (note the
@scope goes between the left parentheses and the left brace):
/** * @namespace Cat */ var Cat = Animal.extend(/** @scope: Cat */{
Now running the JsDoc Toolkit with
-a (Include all functions, even undocumented ones) and it will properly parse the methods in the Base object:
java -jar app/js.jar app/run.js -t=templates/sweet *.js
If you've got a lot of files, you can run this little bit of command line Perl to do the manual work for you - though I recommend you make a backup, because it'll change the files directly:
perl -pi -e 's?(.*) = (.*)\.extend\({?/**\n * \@namespace\n */\n$1 = $2.extend(/** \@scope $1 */{\n?' *.js
Of course you're going to compress and strip out the documentation before you even think about serving it up on your web app though ;-) | https://remysharp.com/2008/01/08/jsdocs-for-base/ | CC-MAIN-2022-21 | refinedweb | 310 | 61.87 |
Link mach-o library into jitter external
While trying to create a Jitter< -->ODE (Open dynamics engine) bridge;
I’ve run into several problems:
1st: Code-warrior (IDE v4.5) can compile externals, but it won’t let
me link in the mach-o library unless if the external is compiled as
mach-o; which yields a frenzy of compiler errors. Specifically, it
ends asking for "/usr/include" to go into the path, then pointing to a
file that only exists in the newer version of code-warrior (only
installed from curiosity, and it’s the free student version — so it
can’t produce libraries).
2nd: Many failed attempts at linking the jitter libraries into XCode
(it just can’t seem to understand the file format the library is in).
How can I convert the library (either ODE or Jitter) into a version
where each would be able to link into the same project?
Thanks,
—
~Michael();
You need to follow the strategy as demonstrated by the Apple Example
project: CFM_MachO_CFM. It might seem cumbersome at first, but it’s
actually not that tough. A good deal of this can be marshaled by only
having a few entry points into your Mach-O bundle. O_CFM.html
My simplethread extern also demonstrate one way to accomplish it from
a Max CFM extern. Keep in mind, you may need to do some header
munging or synthesis (as is the case for the necessary Mach-O pthread
calls in this example) to get this working. on
Note that a Mach-O Universal Binary version of Jitter along with Mach-
O Jitter SDK is coming in the not too distant future (though I might
add, gcc produces markedly slower code than MWCC CFM in our tests so
far…sigh, I suppose this is the price of "progress". Hopefully we
can figure out some tricks to get near MWCC CFM performance on PPC).
Great project, btw. We’ve for a long time been talking about
investigating ODE for use within Jitter. I’m looking forward to
seeing your results.
-Joshua
Another thing which might help you out is an example of how we find
and dynamically load from an auxiliary bundle in the Max search path
(rather than the already loaded system frameworks shown in my
simplethread example). I’ve included the following from our loading
of the Mach-O Cg.framework from within CFM Jitlib.
void jit_gl_shader_framework_init_cg(void)
{
OSStatus err;
short path;
char name[256];
g_jit_gl_shader_cg_framework_ok = FALSE;
if (!nameinpath("Cg.framework", &path))
{
char outname[1024];
char natname[1024];
if (!path_topathname(path, "", outname))
{
FSSpec fs;
CFStringRef str;
CFURLRef url;
path_nameconform(outname, natname, PATH_STYLE_NATIVE,
PATH_TYPE_ABSOLUTE);
path_tospec(0, natname, &fs);
str = CFStringCreateWithCString(kCFAllocatorDefault, natname,
kCFStringEncodingASCII);
if (url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, str,
kCFURLHFSPathStyle, true))
{
if (g_cg_bundle_ref = CFBundleCreate(kCFAllocatorDefault, url))
{
// post("jit.gl.shader: loaded CG framework.");
// include the bundle to cfm binding operations
#include "jit.gl.shader.cg.cfm.c"
// toggle global flag
g_jit_gl_shader_cg_framework_ok = TRUE;
}
broken:
CFRelease(url);
}
else
{
error("jit.gl.shader: error loading CG framework : no URL from
FSRef.");
}
CFRelease(str);
}
}
else
{
error("jit.gl.shader: unable to find CG framework.");
}
}
// jit.gl.shader.cg.cfm.h is of the following form for each function
pointer
// cgCreateProgram
typedef CGprogram (*tf_cgCreateProgram)(CGcontext ctx, CGenum
program_type, const char* program, CGprofile profile, const char*
entry, const char* *args);
tf_cgCreateProgram pf_cgCreateProgram=NULL;
// jit.gl.shader.cg.cfm.c is of the following form for each function
pointer
pf_cgCreateProgram = CFBundleGetFunctionPointerForName
(g_cg_bundle_ref, CFSTR("cgCreateProgram"));
if(!pf_cgCreateProgram) {
error("jit.gl.shader: unable to load CG framework function
‘cgCreateProgram'");
}
This sort of thing can often be handled by some creative perl
scripting to make the appropriate files. I have a crummy one I hacked
together for some munging of the Max header files for other purposes.
If you want this as an example, let me know and I can send you that
monster off list.
Hope this helps.
-Joshua
Hi Joshua,
Do you have any information on these codegen regressions vs MWCC on
power pc? Is there increased function call overhead? Poor register
usage?
If you do find any glaring issues with gcc codegen vs MWCC please send
them my way in addition to whatever you would have normally done with
them. I would be happy to file copious bugs against the dev tools
team over here.
Obviously most helpful would be minimal snipets of code along with the
compiler options you’re using and generated assembly from MWCC and gcc
and timing info. I am guessing you guys are doing this sort of
analysis anyhow, pushing it upstream to Apple might allow you to not
kludge quite so much.
_Mark
Hi there,
Check out PMDP by Cyrille Henry. Ali Momeni did a max port of the
objects. They use ODE to do physical modelling. There are
codewarrior projects that you can download. -max.sit
best,
wes
Forums > Dev | https://cycling74.com/forums/topic/link-mach-o-library-into-jitter-external/ | CC-MAIN-2016-44 | refinedweb | 803 | 54.93 |
time - get time
#include <time.h>
time_t time(time_t *tloc);
time() function shall return the value of time [CX]
in seconds since the Epoch.
Getting the Current Time
The following example uses the time() function to calculate the time elapsed, in seconds, since
Timing an Event
The following example gets the current time, prints it out in the user's format, and prints the number of minutes to an event being timed.#include <time.h> #include <stdio.h> ... time_t now; int minutes_to_event; ... time(&now); minutes_to_event = ...; printf("The time is "); puts(asctime(localtime(&now))); printf("There are %d minutes to the event.\n", minutes_to_event); ..., time_t is likely to be required to be capable of representing times far in the future. Whether this will be mandated as a 64-bit type or a requirement that a specific date in the future be representable (for example, 10000 AD) is not yet determined. Systems purchased after the approval of this volume of. | http://pubs.opengroup.org/onlinepubs/009695299/functions/time.html | CC-MAIN-2014-52 | refinedweb | 158 | 63.7 |
The Samba-Bugzilla – Bug 11582
I have a patch to build ccache on Solaris/AIX with gcc
Last modified: 2016-04-17 14:49:22 UTC
I have a patch I would like to submit that fixes ccache build on Solaris 10+ and AIX 7. What is the process to submit the patch?
You can attach it to this bug report.
Created attachment 11559 [details]
Check if MAX is not defined
Comment on attachment 11559 [details]
Check if MAX is not defined
--- ./ccache.h 2015-10-08 15:12:14.000000000 -0400
+++ ./ccache.h 2015-10-21 16:31:54.290193000 -0400
@@ -276,6 +276,8 @@
# define PATH_DELIM ":"
#endif
+#ifndef MAX
#define MAX(a, b) (((a) > (b)) ? (a) : (b))
+#endif
#endif /* ifndef CCACHE_H */
Created attachment 11560 [details]
Updated check ifndef MAX
Created attachment 11561 [details]
feature Macro's for AIX 7 and Solaris
Looks good to me, applied in 9485354a5542f901dbca9f96930d036bdbdaaf8b. Thanks!
Included in 3.2.5. | https://bugzilla.samba.org/show_bug.cgi?id=11582 | CC-MAIN-2017-22 | refinedweb | 156 | 73.47 |
in reply to
Perl software on multiple files
Question?
&function();
[download]
sub function() {
# do something
}
[download]
Please don't do that. This approach usually becomes a great global mess before your
system has a chance to grow big.
Read Including files again, esp. the first section that hints not to follow the PHP path.
The free Modern Perl book
has specific chapters about modules (i.e.: Managing Real Programs, p. 201ff.)
(...as already suggested by GrandFather and AM).
Then refactor your code into modules (*.pm not *.pl BTW) that can be re-used
and properly encapsulate/abstracts functionality.
Check first if the functionality required is already available
as a core module or a download from CPAN.
Decide if it is better to have a functional- (what you do now)
or an OO-interface and what really needs to be exported into your main.pl ($main::) namespace.
Since you didn't gave us much details, it is hard to give you more specific advice (see ww's comment below).
BTW: The &function() syntax is usually/probably not what you want (circumvents prototypes;
makes current @_ visible to called sub; see perlsub | http://www.perlmonks.org/?node_id=927731 | CC-MAIN-2015-35 | refinedweb | 190 | 67.65 |
Re: RegEx and Vb.net /// "Unrecognized escape sequence"
- From: "sloan" <sloan@xxxxxxxxx>
- Date: Tue, 27 Mar 2007 14:14:29 -0400
//and note
that \ is the escape characters for regular expressions regardless of the
"host language".//
Ahhh....
Thus my error in my C# to VB.net translation.
Thanks Patrice.
"Patrice" <> wrote in message
news:eiN4UPJcHHA.208@xxxxxxxxxxxxxxxxxxxxxxx
You'll have to use \\ even when not using C#.wouldn't
Try and note
that \ is the escape characters for regular expressions regardless of the
"host language".
Not that \ is the escape character for regular expressions. So this is not
because you are using VB.NET that you have to change the regular
"sloan" <sloan@xxxxxxxxx> a écrit dans le message de news:
OYCvZzIcHHA.1244@xxxxxxxxxxxxxxxxxxxxxxx
//quote
I'm not sure why you're using double slashes in your path names as// end quote
VB.Net does not use the \ character as an escape character in strings.
That's the issue. I *don't want* to use the double slashed, and
workworkthink (since I'm in vb.net on this one , and not c# ) I'd have to use
delimited characters.
But the code breaks .... if I use single slashes.
//quote
Dim filename As String = "c:\wutemp\myfile.txt"//end quote
Dim replaceValue As String = "c:\newFolder"
Dim newFilename As String = Path.Combine(replaceValue,
Path.GetFileName(filename))
That would be an option, but I actually have more complex rules, that
RegEx
solves perfectly.
I just used the "change folder name" as a dumbed down example.
I did all this at home in C# , and had it working. I brought it into
aaand this project was vb.net , and I converted the code.
<dunawayc@xxxxxxxxx> wrote in message
news:1175012533.361598.190110@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Mar 27, 11:13 am, "sloan" <s...@xxxxxxxxx> wrote:
I have a fairly simple RegEx code below.
I am given a file name, (which I don't control) , and need to change
\ )\ )betterbetterfolder name in it.
The code below is choking on the filename not being escaped.
"Unrecognized escape sequence"
While I can escape the findValue and replaceValue,
I don't necessarily control the fileName value. Aka, all I can do is
manually string.Replace the fileName value. (Unless someone knows
than I)
Do I have to do a string.Replace here? ( to make all the \ into
simplysimply
Or am I missing some trick in vb.net.
----------Start VB.Net code
Dim fileName As String
fileName = "C:\wutemp\myfile.txt" '<< this is given to me, I cannot
"IGNORE"IGNOREsay " filename = "C:\\wutemp\\myfile.txt" "
Dim replaceRegEx As System.Text.RegularExpressions.Regex = New
System.Text.RegularExpressions.Regex(fileName, getRegexOptions())
Dim findValue As String = "\wutemp\"
Dim replaceValue As String = "\newfolder\"
Dim newFileName As String = replaceRegEx.Replace(fileName, findValue,
replaceValue)
Private Function GetRegexOptions() As RegexOptions
Dim options As RegexOptions = New RegexOptions
options = options Or RegexOptions.IgnoreCase
Return options
End Function
PS
This is a repost. But I marked the other post (in .language.vb) as
do not reply here".
..
Why not just use the Path class in the System.IO namespace?
string filename = @"c:\wutemp\myfile.txt";
string replaceValue = @"c:\newfolder";
string newFileName = Path.Combine(replaceValue,
Path.GetFileName(filename));
Chris
.
- References:
- RegEx and Vb.net /// "Unrecognized escape sequence"
- From: sloan
- Re: RegEx and Vb.net /// "Unrecognized escape sequence"
- From: dunawayc
- Re: RegEx and Vb.net /// "Unrecognized escape sequence"
- From: sloan
- Re: RegEx and Vb.net /// "Unrecognized escape sequence"
- From: Patrice
- Prev by Date: Re: Console application will only run on machine where application was compiled
- Next by Date: RE: gc.KeepAlive - is this the reality of garbage collection
- Previous by thread: Re: RegEx and Vb.net /// "Unrecognized escape sequence"
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- Index(es): | http://www.tech-archive.net/Archive/DotNet/microsoft.public.dotnet.framework/2007-03/msg00501.html | crawl-002 | refinedweb | 623 | 60.92 |
okular
#include <sourcereference.h>
Detailed Description
Defines a source reference.
A source reference is a reference to one of the source(s) of the loaded document.
Definition at line 25 of file sourcereference.h.
Constructor & Destructor Documentation
Creates a reference to the row
row and column
column of the source
fileName.
Definition at line 32 of file sourcereference.cpp.
Destroys the source reference.
Definition at line 40 of file sourcereference.cpp.
Member Function Documentation
Returns the column of the position in the source file.
Definition at line 55 of file sourcereference.cpp.
Returns the filename of the source.
Definition at line 45 of file sourcereference.cpp.
Returns the row of the position in the source file.
Definition at line 50 of file sourcereference.cpp.
The documentation for this class was generated from the following files:
Documentation copyright © 1996-2020 The KDE developers.
Generated on Sun Feb 16 2020 04:30:02 by doxygen 1.8.7 written by Dimitri van Heesch, © 1997-2006
KDE's Doxygen guidelines are available online. | https://api.kde.org/4.x-api/kdegraphics-apidocs/okular/html/classOkular_1_1SourceReference.html | CC-MAIN-2020-10 | refinedweb | 170 | 53.78 |
On 22 August 2016 at 20:16, Josh Triplett <j...@joshtriplett.org> wrote: > On Mon, Aug 22, 2016 at 07:36:31PM +0100, Richard wrote: >> On 21 Aug 2016 15:07, "Josh Triplett" <j...@joshtriplett.org> wrote: >> > I'd like to see it work more automatically than that. Perhaps a >> > separate environment variable to set the client-side namespace? >> >> How about a config option? That could be set globally, per repository, in >> the environment or on the command line. > > That might work, though you wouldn't normally want to set it globally or > per-repository (since it affects access to a repository and you'd > typically want to use multiple different values or it wouldn't have much > point).
Advertising
Globally is a bit contrived, but could be used to keep the top-level namespace clean so you might opt to default to fetching into a namespace called "main" so that if you need to temporarily fetch into a different namespace it wouldn't be problematic. Perhaps it's a kernel tree from a vendor with a messy branch naming scheme so you don't want to fetch it into your primary namespace and make it difficult to find your branches, but you don't know which of their branches you need until you've got them all. So you fetch into the different namespace rather than a fresh clone to avoid re-fetching everything (numerous alternative solutions exist) Then once you've found out which branch you need, you make a note, switch back to the "main" namespace and re-fetch just that branch. A per repository default namespace could also be useful if an upstream repository has multiple namespaces (code vs documentation maybe) you could fetch them all and then switch between them when you need to work on different parts, and if it's config rather than an environment variable it will persist between shell sessions easier. -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at | https://www.mail-archive.com/git@vger.kernel.org/msg101441.html | CC-MAIN-2016-50 | refinedweb | 345 | 55.07 |
Mrs.Kwirk – A Tomato with an Attitude Now Bridged to Windows 10
Remember when I highlighted the UWP Community Toolkit, Do you UWP? Then you'll want this...? How I stated that if you build UWP app's, you HAVE to get it?
Well it looks like the community really did "get it!" Not only downloading it, but actually contributing to it too. And that has powered the latest release, v1.1...
Today we are releasing the first update to the UWP Community Toolkit. To see the updates, first:
- Install the UWP Community Toolkit Sample App directly from the Windows Store
- Read the documentation
In under a month since the first release, we are humbled by the positive feedback we have received so far and are excited to see all the contributions the community has made, including:
- 39 community contributors
- 188 accepted pull requests
- 173 issues closed
- 678 stars
- 159 forks
...
Here’s a summary of what’s new in V1.1:
- .NET Foundation. We are excited to announce that the UWP Community Toolkit has joined the .NET Foundation, a vibrant community of open-sourced projects focused on the future of the .NET ecosystem.
- Updates and new features. The focus of this release is to improve the quality of the toolkit by addressing feedback we received through GitHub and the Store Sample App. Full list available in the Release Notes,
- Sample app. The UWP Community Toolkit Sample App has been updated to include the new features of this release. The Sample App is the best way to preview the features of the toolkit.
- Documentation. As the project joins the .NET Foundation, we moved the documentation to a new location, directly connected to GitHub.
... [click through to read the post]
The toolkit is available as NuGet packages that can be added to any existing or new project using Visual Studio.
1) Download Visual Studio 2015 Update 3 with Windows developer tools and the Windows 10 SDK. Important: Ensure you choose the custom install option and select the Universal Windows App Development Tools.
2) Open an existing project, or create a new project using the Blank App template under Visual C# -> Windows -> Universal. Important: Build 10586 or higher is supported by current version of the Toolkit.
3) In Solution Explorer panel, right click on your project name and select Manage NuGet Packages. Search for Microsoft.Toolkit.UWP, and choose your desired NuGet Packages from the list.
4) Add a reference to the toolkit in your XAML pages or C#
a. In your XAML page, add a reference at the top of your page
xmlns:controls="using:Microsoft.Toolkit.Uwp.UI.Controls"
- b. In your C# page, add the namespaces to the toolkit
using Microsoft.Toolkit.Uwp;
- 5) You can copy and paste code snippets for each feature from the UWP Community Toolkit Sample App.
Head over to UWPCommunityToolkit and give it a go!
Follow @CH9
Follow @coding4fun
Follow @gduncan411
This conversation has been locked by the site admins. No new comments can be made. | https://channel9.msdn.com/coding4fun/blog/UWP-with-UWP-Community-Toolkit-11?WT.mc_id=DX_MVP4025064 | CC-MAIN-2021-31 | refinedweb | 502 | 65.12 |
Version: (using KDE 4.2.1)
Compiler: GCC 4.3.3
OS: Linux
Installed from: Slackware Packages
Steps to reproduce:
Trying to do something simple like the following (I've cut out the rest of the relevant PyQT4/ PyKDE4 imports):
from PyKDE4.phonon import Phonon
class MyVideoPlayer(kdeui.KMainWindow):
def __init__(self, parent=None):
self.video_widget = phonon.Phonon.VideoWidget()
self.media_object = phonon.Phonon.MediaObject()
phonon.Phonon.createPath(self.media_object, self.video_widget)
Expected:
It works
Actual:
createPath() throws:
TypeError: argument 2 of createPath() has an invalid type
VideoWidget and AudioOutput in the Python bindings are missing base classes, so do not inherit
from MediaNode. If you look at the C++ documentation, VideoWidget needs
to inherit from Phonon::AbstractVideoOutput as well as QWidget, and
AudioOutput needs to inherit from Phonon::AbstractAudioOutput (and PyKDE4 doesn't even have a binding for AbstractAudiOutput yet).
The patch is trivial (to follow).
This bug is still present in trunk as well as 4.2.1 - it would be nice to fix
this on the 4.2 branch as well for the next 4.2 release, but fixing it on
trunk would be enough.
Created attachment 32444 [details]
Fix PyKDE4 Phonon Python bindings
This patch adds a binding for Phonon::AbstractAudioOutput, and adds the missing base classes to the AudioOutput and VideoWidget bindings.
Simon,
I'm adding you to CC: here as I believe the Python bindings are your territory?
However, this might be a bug in twine - the sime_pykde4{2,3}.prj files appear to do strange things with these files & classes, so the real issue might be there (I don't understand the project files or Twine enough to know what it's trying to do here).
SVN commit 1228245 by lbeltrame:
Unbreak Python Phonon bindings. Now it is possible to use a VideoWidget again with a MediaSource object, which would throw a TypeError earlier (this was due to a missing inheritance of a class). My testing confirms that it now works.
Original patch by Carlos Corbacho (with minimal changes on my part). Thanks!
BUG: 188315
M +1 -1 audiooutput.sip
M +4 -1 videowidget.sip
WebSVN link:
Git commit a5db3ab2ccf05bd70649e831386fe2320319a336 by Luca Beltrame.
Committed on 16/04/2011 at 10:30.
Pushed by lbeltrame into branch 'master'.
Forward port SVN r1228245 to PyKDE4 git master:
Unbreak Python Phonon bindings. Now it is possible to use a VideoWidget again with a MediaSource object, which would throw a TypeError earlier (this was dueto a missing inheritance of a class). My testing confirms that it now works.
Original patch by Carlos Corbacho (with minimal changes on my part).
Thanks!
CCBUG: 188315
M +1 -1 sip/phonon/audiooutput.sip
M +4 -1 sip/phonon/videowidget.sip | https://bugs.kde.org/show_bug.cgi?id=188315 | CC-MAIN-2022-05 | refinedweb | 448 | 58.28 |
- Author:
- macmichael01
- Posted:
- February 7, 2008
- Language:
- Python
- Version:
- .96
- tag django python tags tagging tagger
- Score:
- 4 (after 4 ratings) users have clicked on a particular tag.
More like this
- astimezone template tag by whardier 4 years, 11 months ago
- Markdown and Syntax Highlighting in Django by blinks 8 years, 10 months ago
- Template Tag Caveat by ericmoritz 7 years, 7 months ago
- Decorate Template Tag (In-Line include and extend with local context) by rhomber 6 years ago
- Switch/case conditional tags by gabrielteratos 7 years, 6 months ago
Wouldn't it be easier just to use
django-tagging?
#
nah
#
hi
could you provide maybe some more info on the exact usage of that snippet?
i've saved all the files, packed them into the installed apps in settings.py and an appropriate menue in the admin interface shows up too, but.. how can i tag now specific entries of a blog?
i tried by adding a
from project.tag.models import Tag
to my own models.py and a
tag = Tag()
in my class, doesn't show effect.
and adding tags doesn't work either. there's the form with name, slug and content type, but all combinations just throw "Please correct the error below." :¦
#
You should add a m2m field into you model that you are trying to relate it to. I did not code a TagField() so you cannot use tag = Tag().
So do something similar to this:
tags = models.ManyToManyField('Tag', limit_choices_to={'content_type__app_label': 'SOME_APP_NAME'}, null=True, blank=True)
#
Please login first before commenting. | https://djangosnippets.org/snippets/589/ | CC-MAIN-2016-07 | refinedweb | 259 | 64.61 |
Chapter 9: Access Control
Access Control
web2py includes a powerful and customizable Role Based Access Control mechanism (RBAC).
Here is a definition from Wikipedia:
"Role-Based Access Control (RBAC) is an approach to restricting system access to authorized users. It is a newer alternative approach to mandatory access control (MAC) and discretionary access control (DAC). RBAC is sometimes referred to as role-based security.
RBAC is a policy neutral and flexible access control technology sufficiently powerful to simulate DAC and MAC. Conversely, MAC can simulate RBAC if the role graph is restricted to a tree rather than a partially ordered set.
Prior to the development of RBAC, MAC and DAC were considered to be the only known models for access control: if a model was not MAC, it was considered to be a DAC model, and vice versa. Research in the late 1990s demonstrated that RBAC falls in neither category.
Within an organization, roles are created for various job functions. The permissions to perform certain operations are assigned to specific roles. Members of staff (or other system users) are assigned particular roles, and through those role assignments acquire the permissions to perform particular system functions. Unlike context-based access control (CBAC), RBAC does not look at the message context (such as a connection's source).
Since users are not assigned permissions directly, but only acquire them through their role (or roles), management of individual user rights becomes a matter of simply assigning appropriate roles to the user; this simplifies common operations, such as adding a user, or changing a user's department. dictate how that file could be changed."
The web2py class that implements RBAC is called Auth.
Auth needs (and defines) the following tables:
auth_userstores users' name, email address, password, and status (registration pending, accepted, blocked)
auth_groupstores groups or roles for users in a many-to-many structure. By default, each user is in its own group, but a user can be in multiple groups, and each group can contain multiple users. A group is identified by a role and a description.
auth_membershiplinks users and groups in a many-to-many structure.
auth_permissionlinks groups and permissions. A permission is identified by a name and, optionally, a table and a record. For example, members of a certain group can have "update" permissions on a specific record of a specific table.
auth_eventlogs changes in the other tables and successful access via CRUD to objects controlled by the RBAC.
auth_casis used for Central Authentication Service (CAS). Every web2py application is a CAS provider and can optionally be a CAS consumer.
The schema is reproduced graphically in the image below:
In principle, there is no restriction on the names of the roles and the names of the permissions; the developer can create them to fix the roles and permissions in the organization. Once they have been created, web2py provides an API to check if a user is logged in, if a user is a member of a given group, and/or if the user is a member of any group that has a given required permission.
web2py also provides decorators to restrict access to any function based on login, membership and permissions.
web2py also understands some specific permissions, i.e., those that have a name that correspond to the CRUD methods (create, read, update, delete) and can enforce them automatically without the need to use decorators.
In this chapter, we are going to discuss different parts of RBAC one by one.
Authentication
In order to use RBAC, users need to be identified. This means that they need to register (or be registered) and log in.
Auth provides multiple login methods. The default one consists of identifying users based on the local
auth_user table. Alternatively, it can log in users against third-party authentication systems and single sign on providers such as Google, PAM, LDAP, Facebook, LinkedIn, Dropbox, OpenID, OAuth, etc..
To start using
Auth, you need at least this code in a model file, which is also provided with the web2py "welcome" application and assumes a
db connection object:
By default, web2py uses email for login. If instead you want to log in using username set
auth.define_tables(username=True)
Setting
signature=True adds user and date stamping to auth tables, to track modifications.
Auth has an optional
secure=True argument, which will force authenticated pages to go over HTTPS.
By default, Auth protects logins against cross-site request forgeries (CSRF). This is actually provided by web2py's standard CSRF protection whenever forms are generated in a session. However, under some circumstances, the overhead of creating a session for login,password request and reset attempts may be undesirable. DOS attacks are theoretically possible. CSRF protection can be disabled for Auth forms (as of v 2.6):
Note that doing this purely to avoid session overload on a busy site is not recommended because of the introduced security risk. Instead, see the Deployment chapter for advice on reducing session overheads.
The
passwordfield of the
db.auth_usertable defaults to a
CRYPTvalidator, which needs:
Notice that this function simply displays a
form and therefore it can be customized using normal custom form syntax. The only caveat is that the form displayed by
form=auth() depends on
request.args(0); therefore, if you replace the default
auth() login form with a custom login form, you may need an
if statement like this in the view:.
- login allows users who are registered to log in (if the registration is verified or does not require verification, if it has been approved or does not require approval, and if it has not been blocked).
- logout does what you would expect but also, as the other methods, logs the event and can be used to trigger some event.
- profile allows users to edit their profile, i.e. the content of the
auth_usertable. Notice that this table does not have a fixed structure and can be customized.
- change_password allows users to change their password in a fail-safe way.
- verify_email. If email verification is turned on, then visitors, upon registration, receive an email with a link to verify their email information. The link points to this action.
- retrieve_username. By default, Auth uses email and password for login, but it can, optionally, use username instead of email. In this latter case, if a user forgets his/her username, the
retrieve_usernamemethod allows the user to type the email address and retrieve the username by email.
- request_reset_password. Allows users who forgot their password to request a new password. They will get a confirmation email pointing to reset_password.
- impersonate allows a user to "impersonate" another user. This is important for debugging and for support purposes.
request.args[0]is the id of the user to be impersonated. This is only allowed if the logged in user
has_permission('impersonate', db.auth_user, user_id). You can use
auth.is_impersonating()to check is the current user is impersonating somebody else.
- groups lists the groups of which the current logged in user is a member.
- not_authorized displays an error message when the visitor tried to do something that he/she is not authorized to do
- navbar is a helper that generates a bar with login/register/etc. links.
Logout, profile, change_password, impersonate, and groups require login.
By default they are all exposed, but it is possible to restrict access to only some of these actions.
All of the methods above can be extended or replaced by subclassing Auth.
All of the methods above can be used in separate actions. For example:
def mylogin(): return dict(form=auth.login()) def myregister(): return dict(form=auth.register()) def myprofile(): return dict(form=auth.profile()) ...
To restrict access to functions to only logged in visitors, decorate the function as in the following example
Any function can be decorated, not just exposed actions. Of course this is still only a very simple example of access control. More complex examples will be discussed later.
auth.user_groups.
auth.usercontains a copy of the
db.auth_userrecords for the current logged in user or
Noneotherwise. There is also a
auth.user_idwhich is the same as
auth.user.id(i.e. the id of the current logger in user) or
None.:
You can approve a registration via the appadmin interface. Look into the table
auth_user. Pending registrations have a
registration_key field set to "pending". A registration is approved when this field is set to blank.
Via the appadmin interface, you can also block a user from logging in. Locate the user in the table
auth_user and set the
registration_key to "blocked". "blocked" users are not allowed to log in. Notice that this will prevent a visitor from logging in but it will not force a visitor who is already logged in to log out. The word "disabled" may be used instead of "blocked" if preferred, with exactly the same behavior.
You can also block access to the "register" page completely with this statement:
If you want to allow people to register and automatically log them in after registration but still want to send an email for verification so that they cannot login again after logout, unless they completed the instructions in the email, you can accomplish it as follows:
Other methods of Auth can be restricted in the same way.
Integration with OpenID, Facebook, etc.
You can use the web2py Role Base Access Control and authenticate with other services like OpenID, Facebook, LinkedIn, Google, Dropbox, MySpace, Flickr, etc. The easiest way is to use Janrain Engage (formerly RPX) (Janrain.com).
Dropbox is discussed as a special case in Chapter 14 since it allows more than just login, it also provides storage services for the logged in users.
Janrain Engage is a service that provides middleware authentication. You can register with Janrain.com, register a domain (the name of your app) and set of URLs you will be using, and they will provide you with an API key.
Now edit the model of your web2py application and place the following lines somewhere after the definition of the
auth object :
The first line imports the new login method, the second line disables local registration, and the third line asks web2py to use the RPX login method. You must insert your own
api_key provided by Janrain.com, the domain you choose upon registration and the external
url of your login page. "".
When a new user logins for the first time, web2py creates a new
db.auth_user record associated to the user. It will use the
registration_id field to store a unique id for the user. Most authentication methods will also provide a username, email, first_name and last_name but that is not guaranteed. Which fields are provided depends on the login method selected by the user. If the same user logs in twice using different authentication mechanisms (for example once with OpenID and once with Facebook), Janrain may not recognize his/her as the same user and issue different
registration_id.
You can customize the mapping between the data provided by Janrain and the data stored in
db.auth_user. Here is an example for Facebook:
The keys in the dictionary are fields in
db.auth_user and the values are data entries in the profile object provided by Janrain. Look at the online Janrain documentation for details on the latter.
Janrain will also keep statistics about your users' login.
This login form is fully integrated with web2py Role Based Access Control and you can still create groups, make users members of groups, assign permissions, block users, etc.
Janrain's free Basic service allows up to 2500 unique registered users to sign in annually. Accommodating more users requires an upgrade to one of their paid service tiers. If you prefer not to use Janrain and want to use a different login method (LDAP, PAM, Google, OpenID, OAuth/Facebook, LinkedIn, etc.) you can do so. The API to do so is described later in the chapter.
CAPTCHA and reCAPTCHA
This is what you need to do to use reCAPTCHA:
- Register with reCAPTCHA[recaptcha] and obtain a (PUBLIC_KEY, PRIVATE_KEY) couple for your account. These are just two strings.
- Append the following code to your model after the
authobject is defined:
reCAPTCHA may not work if you access the web site as 'localhost' or '127.0.0.1', because it is registered to work with publicly visible web sites only.
The
Recaptcha constructor takes some optional arguments:
There is an experimental argument,
ajax=True, which uses the ajax API to recaptcha. It can be used with any recaptcha, but it was specifically added to allow recpatcha fields to work in LOAD forms (see Chapter 12 for more about LOAD, which allows web2py to 'plugin' components of a page with ajax ). It's experimental because it may be replaced with automatic detection of when ajax is required.
Notice that
use_ssl=False by default.
options may be a configuration string, e.g.
options="theme:'white', lang:'fr'"
More details: reCAPTCHA[recaptchagoogle] and customizing .
If you do not want to use reCAPTCHA, look into the definition of the
Recaptcha class in "gluon/tools.py", since it is easy to use other CAPTCHA systems.
Notice that
Recaptcha is just a helper that extends
DIV. It generates a dummy field that validates using the
reCaptcha service and, therefore, it can be used in any form, including used defined FORMs:
You can use it in all types of SQLFORM by injection:
Customizing
Auth
The call to
defines all Auth tables that have not been defined already. This means that if you wish to do so, you can define your own
auth_user table.
There are a number of ways to customize auth. The simplest way is to add extra fields:
## after auth = Auth(db) auth.settings.extra_fields['auth_user']= [ Field('address'), Field('city'), Field('zip'), Field('phone')] ## before auth.define_tables(username=True)
You can declare extra fields not just for table "auth_user" but also for other "auth_" tables. Using
extra_fields is the recommended way as it will not break any internal mechanism.
Another way to do this, although not really recommended, consists of defining your auth tables yourself. If a table is declared before
auth.define_tables() it is used instead of the default one. Here is how to do it:
You can add any field you wish, and you can change validators but you cannot remove the fields marked as "required" in this example.
It is important to make "password", "registration_key", "reset_password_key" and "registration_id" fields
readable=False and
writable=False, since a visitor must not be allowed to tamper with them.
If you add a field called "username", it will be used in place of "email" for login. If you do, you will need to add a validator as well:
Note that Auth caches the logged in user in the session and that's what you get in
auth.user, so you need to clear the sessions for the extra fields changes to be reflected in it.
Renaming
Auth tables
Note: auth.signature gets defined when Auth is initialized, which is before you have set the custom table names. To avoid this do:
auth = Auth(db, signature=False)
In that case, auth.signature will instead be defined when you call auth.define_tables(), by which point the custom tables names will already be set.
Other login methods and login forms
Auth provides multiple login methods and hooks to create new login methods. Each supported login method corresponds to a file in the folder
Refer to the documentation in the files themselves for each login method, but here are some examples.
First of all, we need to make a distinction between two types of alternate login methods:
- login methods that use a web2py login form (although the credentials are verified outside web2py). An example is LDAP.
- login methods that require an external single-sign-on form (an example is Google and Facebook).
In the latter case, web2py never gets the login credentials, only a login token issued by the service provider. The token is stored in
db.auth_user.registration_id.
Let's consider examples of the first case:
Basic
Let's say you have an authentication service, for example at the url
that accepts basic access authentication. That means the server accepts HTTP requests with a header of the form:
where the latter string is the base64 encoding of the string username:password. The service responds 200 OK if the user is authorized and 400, 401, 402, 403 or 404 otherwise.
You want to enter username and password using the standard
Auth login form and verify the credentials against such a service. All you need to do is add the following code to your application
Notice that
auth.settings.login_methods is a list of authentication methods that are executed sequentially. By default it is set to
When an alternate method is appended, for example
basic_auth, Auth first tries to log in the visitor based on the content of
auth_user, and when this fails, it tries the next method in the list. If a method succeeds in logging in the visitor, and if
auth.settings.login_methods[0]==auth,
Auth takes the following actions:
- if the user does not exist in
auth_user, a new user is created and the username/email and passwords are stored.
- if the user does exist in
auth_userbut the new accepted password does not match the old stored password, the old password is replaced with the new one (notice that passwords are always stored hashed unless specified otherwise).
If you do not wish to store the new password in
auth_user, then it is sufficient to change the order of login methods, or remove
auth from the list. For example:
The same applies for any other login method described here.
SMTP and Gmail
You can verify login credentials using a remote SMTP server, for example Gmail; i.e., you log the user in if the email and password they provide are valid credentials to access the Gmail SMTP server (
smtp.gmail.com:587). All that is needed is the following code:
The first argument of
email_auth is the address:port of the SMTP server. The second argument is the email domain.
This works with any SMTP server that requires TLS authentication.
PAM
Authentication using Pluggable Authentication Modules (PAM) works as in the previous cases. It allows web2py to authenticate users using the operating system accounts:):
There are additional parameters to let web2py
- read additional data like the username from LDAP
- implement group control
- restrict login access.
See the documentation of
ldap_auth in
web2py/gluon/contrib/login_methods/ldap_auth.py.
Google App Engine
Authentication using Google when running on Google App Engine requires skipping the web2py login form, being redirected to the Google login page, and back upon success. Because the behavior is different than in the previous examples, the API is a little different.
OpenID
We have previously discussed integration with Janrain (which has OpenID support) and that is the easiest way to use OpenID. Yet sometimes you do not want to rely on a third party service and you want to access the OpenID provider directly from the consumer (your app).
Here is an example:
We have previously discussed integration with Janrain, yet sometimes you do not want to rely on a third party service and you want to access a OAuth2.0 provider directly; for example, Facebook, Linkedin, Twitter, Google all of them provide an OAuth2.0 authentication service. web2py handles the OAuth2.0 flow transparently so that a user can be verified against any configured OAuth2.0 provider during login. Other than authentication an OAuth2.0 provider can grant to any web2py application access to user resources with restricted access thought a proprietary API. Google, Twitter, Facebook and so on, all have APIs that can be easily accessed by a web2py application.
It must be underlined that OAuth2.0 is limited only to authentication and authorization (for instance CAS has more functionalities), this means that each OAuth2.0 provider has a different way to receive a unique id from their user database through one of their APIs. Specific methods are well explained on respective provider documentation, they usually consist in a very simple REST call. This is why for each OAuth2.0 provider there is the need to write a few lines of code.
Before writing any instructions in the application model a first step is needed for any provider: registering a new application; this is usually done on provider's site and is explained in provider's documentation.
There are a few things that needs to be known once there is the need to add a new OAuth2.0 provider to your application: 1. the Authorization URI; 2. the Token request URI; 3. the application identification token and secret received upon registration of the new application; 4. the permissions that the provider must grant to the web2py application, i.e. the "scope" (see the provider's documentation); 5. the API call to receive a UID of the authenticating user, as explained on providers documentation.
Point 1 to 4 are used to initialize the authorization endpoint used by web2py to communicate with the OAuth2.0 provider. The unique id is retrieved by web2py with a call to the get_user() method when needed during the login flow; this is where the API call of point 5 is needed.
These are the essential modification that need to be done in your model: a. import OAuthAccount class; b. define a derived OAuthClass implementation; c. override __init__() method of that class; d. override get_user() method of that class. e. instantiate the class with the data of points 1-4 of the above list;
Once the class is instantiated, and the user is authenticated, the web2py application can access the API of the provider any time by using the OAuth2.0 access token by calling the accessToken() method of that class.
What follows is an example of what can be used with Facebook. This is a basic example using Facebook Graph API, remind that, by writing a proper get_user() method, many different things can be done. The example shows how the OAuth2.0 access token can be used when calling the remote API of the provider.
First of all you must install the Facebook Python SDK.
Second, you need the following code in your model:
We have previously discussed integration with Janrain (which has LinkedIn support) and that is the easiest way to use OAuth. Yet sometime you do not want to rely on a third party service or you may want to access LinkedIn directly to get more information than Janrain provides.
Here is an example:
LinkedInAccount requires the "python-linkedin" module installed separately.
X509
You can also login by passing to the page an x509 certificate and your credential will be extracted from the certificate. This requires
M2Crypto installed from
Once you have M2Cryption installed you can do:
You can now authenticate into web2py passing your x509 certificate. How to do this is browser-dependent, but probably you are more likely to use certificates for web services. In this case you can use for example
cURL to try out your authentication:
curl -d "firstName=John&lastName=Smith" -G -v --key private.key --cert server.crt
This works out of the box with Rocket (the web2py built-in web server) but you may need some extra configuration work on the web server side if you are using a different web server. In particular you need to tell your web server where the certificates are located on local host and that it needs to verify certificates coming from the clients. How to do it is web server dependent and therefore omitted here.
Multiple login forms
Some login methods modify the login_form, some do not. When they do that, they may not be able to coexist. Yet some coexist by providing multiple login forms in the same page. web2py provides a way to do it. Here is an example mixing normal login (auth) and RPX login (janrain.com):
If signals are set and a parameter in request matches any signals, it will return the call of
other_form.login_form instead.
other_form can handle some particular situations, for example, multiple steps of OpenID login inside
other_form.login_form.
Otherwise it will render the normal login form together with the
other_form..
Mail and
Auth
You can read more about web2py API for emails and email configuration in Chapter 8. Here we limit the discussion to the interaction between
Auth.
Define a mailer with
from gluon.tools import Mail mail = Mail() mail.settings.server = 'smtp.example.com:25' mail.settings.sender = 'you@example.com' mail.settings.login = 'username:password'
or simply use the mailer provided by.
Two-step verification
Two-step verification (or Two-factor authentication) is a way of improving authentication security. The setting adds an extra step in the login process. In the first step, users are shown the standard username/password form. If they successfully pass this challenge by submitting the correct username and password, and two-factor authentication is enabled for the user, the server will present a second form before logging them in.
This functionality can be enabled on a per-user basis:
This case is a good example for apps where users can enable/disable two-factor authentication by them self..
- Create a group (also known as a role) for the two-step verification. In this example it will be called
auth2stepand the description may be
Two-step verification.
- Give a user membership of this role.
- Add the following setting in the model where you created and configured your auth object (probably in the model db.py):
- Don’t forget to configure the email server in db.py
This functionality can be enabled for the entire app:.
This case will effect over all the user in the application. For example, if your office IP is 93.56.854.54 and you don't want two-factor authentication from your office IP. In your models:
Other options that can be applied over the examples before:
Example 1: If you want to send the code by SMS instead of email. In your models write:
For
def _sendsms(...) receive two values: user and auth_two_factor:
- user: it is a row with all his parameters. You can access them: user.email, user.first_name, etc.
- auth_two_factor: string that contains the authentication code.
Note that in case you want to send an SMS, you will need to add extra field, for example
phone in your user table. In this case you can access to the phone field as
user.phone. More info how to send an SMS with web2py Emails-and-SMS
Example 2: If you want to send the code by SMS and create or own code:
Example 3: The code is generated by a external client. For example Mobile OTP Client:
MOTP (Mobile one time password) allows you to login with a one time password (OTP) generated on a motp client, motp clients are available for practically all platforms. To know more about OTP visit wiki-One-time-password to know more visit MOTP
For the next example we will use DroidOTP. It is a free app and it can be found in Play Store for Android. Once you have installed:
- Create a new profile, for example
test
- Initialize a secret key shaking your phone.
In your models copy and paste:
The secret key generated before with your phone need to be introduced into
motp_secret field. The secret should be not reused, for security reasons. Choose one PIN. It can be numbers, letters or a mix. Go to your phone, choose your profile and type the PIN you have introduced before in the form. You got the authenticator code to use in your app!!
Note that for this way of two-factor authentication phone and server (where web2py app is hosted) need to be synchronized (on time). They can be in a different time zone. This is because the OTP use Unix time stamp. It tracks the time as a running total of seconds.
Some extra parameters for configuration:
Set your custom attempts to login:
Message to return in case the code is incorrect:
To customize the email template:
To customize two-factor form:.
gives permission "name" (user defined) on the object "object" (also user defined) to members of the group
group_id. If "object" is a tablename then the permission can refer to the entire table by setting
record_id to a value of zero, or the permission can refer to a specific record by specifying a
record_id value greater than zero. When giving permissions on tables, it is common to use a permission name in the set ('create', 'read', 'update', 'delete', 'select') since these permissions are understood and can be enforced by.
returns all rows of table "mytable" that user
user_id has "read" permission on. If the
user_id is not specified, then web2py assumes the current logged-in user. The
accessible_query(...) can be combined with other queries to make more complex ones.
accessible_query(...) is the only Auth method to require a JOIN, so it does not work on the Google App Engine.
Assuming the following definitions:
@auth.requires also takes an optional argument
requires_login which defaults to
True. If set to False, it does not require login before evaluating the condition as true/false. The condition can be a boolean value or a function evaluating to boolean.
Note that access to all functions apart from the first one is restricted based on permissions that the visitor may or may not have.
If the visitor is not logged in, then the permission cannot be checked; the visitor is redirected to the login page and then back to the page that requires permissions.
Combining requirements
Occasionally, it is necessary to combine requirements. This can be done via a generic
requires decorator which takes a single argument, a true or false condition. For example, to give access to agents, but only on Tuesday:
or equivalently:
Authorization and CRUD
Using decorators and/or explicit checks provides one way to implement access control.
Another way to implement access control is to always use CRUD (as opposed to
SQLFORM) to access the database and to ask CRUD to enforce access control on database tables and records. This is done by linking
Auth and CRUD with the following statement:
authorize of upload field can be None (the default) or a function that decides whether the user is logged in and has permission to 'read' the current record. In this example, there is no restriction on downloading images linked by the "small_image" field, but we require access control on images linked by the "large_image" field.
Access Control and Basic Authentication
Occasionally, it may be necessary to expose actions that have decorators that require access control as services; i.e., to call them from a program or script and still be able to use authentication to check for authorization.
Auth enables login via basic authentication:.
Application Management via privileged users (Experimental)
Normally administrator functions such as defining users and groups are managed by the server administrator. However, you may want a group of privileged users to have administrator rights for a specific application. This is possible with versions after web2py v2.5.1 (Upgrading an existing application requires the new appadmin controller and the new appadmin.html view, copied from the welcome app. Also, apps created prior to web2py v2.6 need the new javascript file in welcome/static/js/web2py.js)
The concept allows different management settings, each of which allows a user group to edit a certain set of tables in this application.
Example: First, create a group (also known as a role) for your privileged users. In this example, it will be called admin. Give a user membership of this role. Second, think of a name to describe this management setting, such as db_admin.
Add the following setting in the model where you created and configured your auth object (probably in the model db):
A menu item has the URL like below, passing the management setting name as an arg:
This URL appears as /appadmin/manage/auth.
Advanced use
This mechanism allows multiple management settings; each additional management setting is just another key defined in auth.settings.manager_actions.
For example, you may want a group of users (such as 'Super') to have access to every table in a management setting called "db_admin", and another group (such as 'Content Manager') to have admin access to tables relating to content in a management setting called "content_admin".
This can be set up like this:
(The heading key is optional. If missing, a smart default will be used)
You could then make two new menu items with these URLs:
The management setting called "content_mgr_group_v2" shows some more advanced possibilities. The key smartgrid_args is passed to the smartgrid used to edit or view the tables. Apart from the special key DEFAULT, table names are passed as keys (such as the table called "comments"). The syntax in this example names the tables as a list of strings, using the key db=content_db to specify the database..
Auth Settings and messages
Here is a list of all parameters that can be customized for Auth
The following must point to a
gluon.tools.Mail object to allow
auth to send emails:
Read more about setting up mail here: Mail and Auth
The following must be the name of the controller that defined the
user action:
The following was a very important setting in older web2py versions:
Where it was set to something like "sha512:a-pass-phrase" and passed to the CRYPT validator for the "password" field of the
auth_user table, providing the algorithm and a-pass-phrase used to hash the passwords. However, web2py no longers needs this setting because it handles this automatically.
By default, auth also requires a minimum password length of 4. This can be changed:
To disable):
Note: If your app is based on the standard scaffold app Welcome, you use the auth.navbar. To get the settings below to take effect, you need to edit layout.html and set argument referrer_actions = None. auth.navbar(mode='dropdown',referrer_actions=None)
It is also possible to keep referrer_actions for some auth events. For example
If the default behavior is left unchanged, auth.navbar uses the _next URL parameter, and uses that to send the user back to the referring page. However, if navbar's default auto-referring behavior is changed, the settings below will take effect.
You can change this variable and redirect the user elsewhere.
Often
on_failed_authorization is a URL but it can be a function that returns the URL and it will be called on failed authorization.
These are lists of callbacks that should be executed after form validation for each of the corresponding action before any database IO::
If the
.captcha settings points to a
gluon.tools.Recaptcha, all forms for which the corresponding option (like
.login_captcha) is set to
None will have a captcha, while those for which the corresponding option is set to
False will not. If, instead,
.captcha is set to
None, only those form who have a corresponding option set to a
gluon.tools.Recaptcha object will have captcha and the others will not.
This is the login session expiration time: "bootstrap3_inline", "table3cols", "table2cols", "divs" and "ul"; for all options, see gluon/sqlhtml.py):
add|del|has membership logs allow the use of "%(user_id)s" and "%(group_id)s".
add|del|has permission logs allow the use of "%(user_id)s", "%(name)s", "%(table_name)s", and "%(record_id)s".
Central Authentication Service
web2py provides support for third party authentication and single sign on. Here we discuss the Central Authentication Service (CAS) which is an industry standard and both client and server are built-into web2py.
CAS is an open protocol for distributed authentication and it works in the following way: When a visitor arrives at our web site, our application check in the session if the user is already authenticated (for example via a
session.token object). If the user is not authenticated, the controller redirects the visitor from the CAS appliance, where the user can log in, register, and manage his credentials (name, email and password). If the user registers, he receives an email, and registration is not complete until he responds to the email. Once the user has successfully registered and logged in, the CAS appliance redirects the user to our application together with a key. Our application uses the key to get the credentials of the user via an HTTP request in the background to the CAS server.
Using this mechanism, multiple applications can use a single sign-on via a single CAS server. The server providing authentication is called a service provider. Applications seeking to authenticate visitors are called service consumers.
CAS is similar to OpenID, with one main difference. In the case of OpenID, the visitor chooses the service provider. In the case of CAS, our application makes this choice, making CAS more secure.
Running a web2py CAS provider is as easy as copying the scaffolding app. In fact any web2py app that exposes the action
## in provider app def user(): return dict(form=auth())
is a CAS 2.0 provider and its services can be accessed at the URL
(we assume the app to be called "provider").
You can access this service from any other web application (the consumer) by simply delegating authentication to the provider:
When you visit the login url the consumer app, it will redirect you to the provider app which will perform authentication and will redirect back to the consumer. All processes of registration, logout, change password, retrieve password, have to be completed on the provider app. An entry about the logged-in user will be created on the consumer side so that you add extra fields and have a local profile. Thanks to CAS 2.0 all fields that are readable on the provider and have a corresponding field in the
auth_user table of the consumer will be copied automatically.
Auth(...,cas_provider='...') works with third party providers and supports CAS 1.0 and 2.0. The version is detected automatically. By default it builds the URLs of the provider from a base (the
cas_provider url above) by appending
These can be changed in consumer and in provider
## in consumer or provider app (must match) auth.settings.cas_actions['login']='login' auth.settings.cas_actions['validate']='validate' auth.settings.cas_actions['logout']='logout'
If you want to connect to a web2py CAS provider from a different domain, you must enable them by appending to the list of allowed domains:
Using web2py to authorize non-web2py apps
This is possible but dependent on the web server. here we assume two applications running under the same web server: Apache with
mod_wsgi. One of the applications is web2py with an app proving access control via Auth. The other can be a CGI script, a PHP program or anything else. We want to instruct the web server to ask permission to the former application when a client requests access to the latter.
First of all we need to modify the web2py application and add the following controller:
which returns
true if the user is logged in and
false otherwise. Now run a web2py process in background:
nohup python web2py.py -a '' -p 8002
Port 8002 is a must and there is no need to enable admin so no admin password.
Then we need to edit the Apache config file (for example "/etc/apache2/sites-available/default") and instruct apache so that when the non-web2py program is called, it should call the above
check action instead and only if it returns
true it should proceed and respond to the request, else if should deny access.
Because web2py and the non-web2py application run under the same domain, if the user is logged into the web2py app, the web2py session cookie will be passed to Apache even when the other app is requested and will allow credential verification.
In order to achieve this we need a script, "web2py/scripts/access.wsgi" that can play this trick. The script ships with web2py. All we need to do it tell apache to call this script, the URL of the application needing access control, and the location of the script:
<VirtualHost *:80> WSGIDaemonProcess web2py user=www-data group=www-data WSGIProcessGroup web2py WSGIScriptAlias / /home/www-data/web2py/wsgihandler.py AliasMatch ^myapp/path/needing/authentication/myfile /path/to/myfile <Directory /path/to/> WSGIAccessScript /path/to/web2py/scripts/access.wsgi </Directory> </VirtualHost>
Here "^myapp/path/needing/authentication/myfile" is the regular expression that should match the incoming request and "/path/to/" is the absolute location of the web2py folder.
The "access.wsgi" script contains the following line:
URL_CHECK_ACCESS = ''
which points to the web2py application we have requested but you can edit it to point to a specific application, running on a port other than 8002.
You can also change the
check_access() action and make its logic more complex. This action can retrieve the URL that was originally requested using the environment variable
request.env.request_uri
and you can implement more complex rules: | http://web2py.com/books/default/chapter/29/09 | CC-MAIN-2016-30 | refinedweb | 6,834 | 54.73 |
maybe i should just change my major! lol well...the exercise asks us to calculate charges for a parking garage. there's a $2.00 minimum fee for less than 3 hours, and a $0.50 charge for each additional hour, but the charge can't exceed $10.00. they want it in this kind of format:
Car Hours Charges
1 1.5 2.00
2 4.0 2.50
3 24.0 10.00
TOTAL 29.5 14.50
and this is what i have so far...laugh if u want...i'm so lost. i can't even tell if i've declared my variables right, or if my functions even work...i get continuous errors and don't know where to start. if there's any way anyone can help me, i'd greatly appreciate it.
/* Calculate the total charges and the total hours for the parking garage. */
#include <iostream>
using std::cout;
using std::cin;
using std::endl;
int charges (chargesa, chargesb, chargesc)
int totalhours (a, b, c)
int calculatecharges (chargesa, chargesb, chargesc)
int main()
{
int a, b, c;
cout<<"Enter the number of hours for CAR 1:";
cin>>a;
cout<<"Enter the number of hours for CAR 2:";
cin>>b;
cout<<"Enter the number of hours for CAR 3:";
cin>>c;
return 0;
}
int charges (chargesa,chargesb,chargesc)
{
int chargesa = a * 0.50
if (a <= 3)
chargesa = 2.00
if (a > 3)
chargesa = (a - 3) * 0.50
if (chargesa >= 10.00)
chargesa = 10.00
int chargesb = b * 0.50
if (b <= 3)
chargesb = 2.00
if (b > 3)
chargesb = (b - 3) * 0.50
if (chargesb >= 10.00)
chargesb = 10.00
int chargesc = c * 0.50
if (c <= 3)
chargesc = 2.00
if (c > 3)
chargesc = (c - 3) * 0.50
if (chargesc >= 10.00)
chargesc = 10.00
cout<<"CAR 1 CHARGES:"<<chargesa;
cout<<"CAR 2 CHARGES:"<<chargesb;
cout<<"CAR 3 CHARGES:"<<chargesc;
}
int totalhours (a, b, c)
{
int totalhours = a + b + c
}
int calculatecharges (chargesa, chargesb, chargesc)
{
int calculatecharges = chargesa + chargesb + chargesc
}
P.S. - ur more than welcome to comment with ur opinion on whether or not i should change my major...especially after reading that code
:p | http://cboard.cprogramming.com/cplusplus-programming/11379-im-newbie-i-cant-understand-errors-my-program-printable-thread.html | CC-MAIN-2015-06 | refinedweb | 362 | 87.72 |
Back?
Configuring NetBeans Code Templates
So, I’m sitting there making a C++ class, minding my own business and…
#ifndef FOO_H
#define FOO_H
class foo {
public:
virtual ~foo();
foo();
foo(const foo& orig);
private:
};
#endif /* FOO_H */
What?! NO! Where are my 500 nested namespaces?! Why is this default constructor public?! Where is my operator=?! Why would they do this?! No wonder the cool kids use Eclipse…
Luckily for us, this is fixable.
First, launch NetBeans.
Click Tools->Templates
Click Settings. First, we need to create some custom properties. I like to use a universal top-level namespace, and a subject-specific namespace for my personal projects. Enter:
BASE_NAMESPACE=clt
SUB_NAMESPACE=/*PLACEHOLDER*/
Save and close the User.properties tab. Click Tools->Templates. Expand C++, and click class.h. Click Open in Editor. You’ll see some suspiciously familiar text. Let’s go ahead and best practices it up:
#ifndef %<%GUARD_NAME%>%
#define %<%GUARD_NAME%>%
namespace %<%BASE_NAMESPACE%>%
{
namespace %<%SUB_NAMESPACE%>%
{
class %<%CLASSNAME%>%
{
public:
virtual ~%<%CLASSNAME%>%();
private:
%<%CLASSNAME%>%();
%<%CLASSNAME%>%(const %<%CLASSNAME%>%& orig);
%<%CLASSNAME%>%& operator=(const %<%CLASSNAME%>%& orig);
};
}
}
#endif /* %<%GUARD_NAME%>% */
We’ve declared operator=, and we’ve moved the default constructor, copy constructor, and operator= into the private section. We’ve also added our namespaces. Save and close the class.h tab. While we’re at it, why don’t we update the Class.cpp file. Click Tools->Templates. Expand C++, and click C++ Class. Click Open in Editor. Let’s use our namespaces, and add our operator=:
#include %<%QUOTES%>%%<%NAME%>%.%<%DEFAULT_HEADER_EXT%>%%<%QUOTES%>%
using namespace %<%BASE_NAMESPACE%>%::%<%SUB_NAMESPACE%>%;
%<%CLASSNAME%>%::%<%CLASSNAME%>%() {
}
%<%CLASSNAME%>%::%<%CLASSNAME%>%(const %<%CLASSNAME%>%& orig) {
}
%<%CLASSNAME%>%::~%<%CLASSNAME%>%() {
}
%<%CLASSNAME%>%& %<%CLASSNAME%>%::operator=(const %<%CLASSNAME%>%& orig){
}
Save and close the C++ Class tab. Now, let’s try this again. Right click your project, and select New->C++ Class… You should now end up with a .cpp file and .h file that look like this:
#ifndef FOO_H
#define FOO_H
namespace clt {
namespace /*PLACEHOLDER*/ {
class foo {
public:
virtual ~foo();
private:
foo();
foo(const foo& orig);
foo& operator=(const foo& orig);
};
}
}
#endif /* FOO_H */
…and…
#include "foo.h"
using namespace clt::/*PLACEHOLDER*/;
foo::foo() {
}
foo::foo(const foo& orig) {
}
foo::~foo() {
}
foo& foo::operator=(const foo& orig) {
}
You’ll need to change /*PLACEHOLDER*/ to an actual name before you can use these files, but I like the red jaggies; makes it hard to forget to fix them. Regardelss, we now have a class template that’d make Scott Meyers proud! | https://doingmyprogramming.wordpress.com/category/programming/namespaces/ | CC-MAIN-2017-47 | refinedweb | 395 | 58.89 |
Belarus won its first-ever team gold in World Championships history, scoring 169.622. Second was the USA with 166.845. Ukraine finished third with 165.483.
"We did a nice job and nobody had mistakes," said Ivankov. "Nobody had big mistakes, and that is why we are the champions."
Defending world and Olympic champions China, who sent a team of newcomers so its top gymnasts could train for the upcoming Chinese National Games, finished fifth. Absent from the 2001 Worlds has been the Japanese team, who withdrew earlier this month, citing security reasons.
"Today we are the champions," continued Ivankov, "but the next time, we want to compete with the number one Chinese team and Japan, and do it again."
Click here for IG Online's special event coverage of the 2001 World Gymnastics Championships!
Romania finished first in the preliminaries with 146.646, over the USA (145.147), the Netherlands (144.149), and Russia (144.134).
Unlike the preliminaries, in which five gymnasts per team competed on each event (with four of the scores counting), the team finals involve only three gymnasts per team on each event. All scores will count, which could spell disaster for any team that suffers an injury to one of its gymnasts. (The men's finals on Wednesday afternoon's saw Korea eliminated from the medal hunt, when one of their gymnasts was injured on rings and they had to count his score of 0.00.)
Inspite of his team's comfortable margin of victory in the preliminaries, Belu said the team finals offer his team no advantage.
"Times have changed," Belu said. "It is not a surprise to see The Netherlands on the 'unofficial' podium. The U.S. also has a very motivated team. The finals will be a fresh competition."
Speaking after a pained performance in the women's team qualifiying competition, Zamolodchikova, limping on a swollen and bruised foot, said she would not be competing in the team final Wednesday. With her Russia team already down to five members after an ankle injury to Russian Cup champion Yekaterina Privalova, the team relied tonight on Zamolodchikova, in case of an injury to another gymnast. (In team preliminaries, five gymnasts compete on each event, with the best four scores counting. In finals, only three gymnasts will compete on each event and all scores will be dropped.) Zamolodchikova, the double Olympic gold medallist from the Sydney Games, did not qualify to the all-around or any event finals.
Zamolodchikova, 19, said she was unsure whether her foot was broken. X-rays were planned for Wednesday.
Zamolodchikova's teammate, Svetlana Khorkina, dismissed her team's fourth place result tonight. "This is just preliminaries," said Khorkina, currently the highest scorer in the all-around and in three of the four events. "The competition is ahead. In finals we shall fight."
This past weekend, Khorkina, the 1997 World Champion and two-time Olympic gold medallist, bloodied herself when she landed heavily on her face on a tumbling pass. "Her nose is sore," said Pilkin, "but she has gotten her composure back."
As to why she took the fall, Pilkin simply pointed out the strenuus demands of the sport and its rules. "Gymnastics today is complicated," explained Pilkin. "The new Code of Points is hard, and the level of difficulty is going up, so there are lots of falls."
(Also taking an ugly fall last week was the USA's Mohini Bhardwaj, who severely skinned her nose and forehead when she peeled off uneven bars on a freehip and struck her face on the bar).
Khorkina's teammate Yelena Zamolodchikova, whose podium training was hindered by an injury, trained all her tumbling on Saturday and is also ready to compete.
"Everything is normal for her," said Viktor Gavrichenkov, coach of Zamoldochikova's teammate Natalia Ziganshina.
The Russian team will begin competition Tuesday, competing in the seventh subdivison of the women's team and individual qualifications.
"We have a Russian saying," said Nemov, who competed four events for his team. "'When we are down, we try to look up.'"
Competing in the second subdivision, Russia suffered errors on every event. (See competition report for details.) Nemov cited various reasons for the team's inconsistency, from the new Code of Points to the team's early draw. "We were too early in the morning," he said. "But of course we did our best to get ready but you know what happened. We had a lot of mistakes."
Russia was also hampered by various injuries to its team members. Two-time Olympian Yevgeny Podgorny watched from the sidelines, having injured his elbow on Thursday in podium training, and world champion Nikolai Kryukov is limited by a back injury. Additionally, team member Yevgeny Krylov strained ligaments on his leg in podium training.
"Half the team is injured, so we couldn't do much," continued Nemov, who rated his own preparation level at about 65%. "Nobody could expect much success in this situation, but we did our best and hope for the best."
The top eight teams from the Sunday and Monday's qualifications advance to Wednesday's team finals, where the scores start over from zero.
The Romanian women's team nailed routine after routine in podium training, and looked confident and fit. As a team they had the most consistent performances with very difficult routines. Three Romanians (Andreea Raducan, Silvia Stroescu, Andreea Ulmeanu) tumbled double layouts on floor exercise, and three (Raducan, Sabina Cojocar, Carmen Ionescu) consistently stuck their full-twisting somersaults on balance beam.
Raducan looked fitter than she has in recent months, though the left knee she injured this past summer remains taped. She worked most aggressively on balance beam, sticking her acrobatics and double pike dismount.
Also appearing in good shape Friday on the podium was the Spanish women's team, with excellent routines from Sara Moro and Elena Gomez.
Competing in Ghent without a team - but still in contention for individual medals - were Oksana Chusovitina (UZB) and Sun Xiaojiao (CHN). In podium training Chusovitina looked as fit as she has all year, and threw a high level of difficulty. On floor she tumbled a full-twisting double layout, and she vaulted both a tucked Rudi and a layout front-full vaults. Her dismount from uneven bars was giant-full, hop full, full-twisting double layout. Sun appeared sluggish on most of the events but was spectacular as expected on balance beam.
The Australian women trained in the final session tonight, and looked much improved as a team on vault, and showed some well-choreographed floor exercise routines.
The Russian women also performed confidently in podium training this afternoon, but injured team member Yekaterina Privalova was unable to train. With her ankle heavily wrapped, a limping Privalova provided assistance to her teammates by moving mats and chalking up the bars.
The rest of the Russian team looked in top shape with the exception of Yelena Zamolodchikova, who tumbled only layouts during her floor exercise to save her own injured limb. Zamolodchikova worked aggressively on balance beam in her trademark style, adding a new full-twisting back handspring, back handspring, layout stepout, and back tuck to Rulfova. With her injury, Zamolodchikova may be limited in Ghent and may not attempt the new Yurchenko triple-full she has been seriously training since summer. The team trained under the watchful eyes of head coach Leonid Arkayev and Marina Bulashenko, with personal coaches Boris Pilkin, Nadezhda Maslennikova, and Viktor Gavrichenko offering guidance.
Svetlana Khorkina, 1997 world all-around champion, received the warmest applause from the sparse audience at the Flanders Sports Hall for her floor routine; using her Olympic routine from 2000, Khorkina tumbled a tucked full-in and whip-triple twist. The four-time world champion on uneven bars, Khorkina consistently performed her difficult routine on that event.
Russia's Natalia Ziganshina and Maria Zasypkina, both competing in their first world championships, also trained well, especially on beam where they tossed standing Arabian somersaults. Beam and bars specialist Lyudmila Yezhova performed flawlessly on beam with a difficult and elegant routine, but was inconsistent on bars, flying off the apparatus repeatedly.
In the same session as Russia was the Mexican team, led by the explosive Brenda Magaña. On uneven bars, Magaña performed a full-twisting Gienger (Def) and landed her triple back dismount. She also tumbled a double layout, Arabian double front, and piked-full in on floor exercise, and threw a Podkopayeva on vault.
A united American women's team kicked off their podium training with a team huddle, and performed solidly, making few errors. The U.S., loudly cheered by a large American delegation in the audience, looked to all be in great shape and was one of the few teams to formally perform complete routines. Though only one team member, Mohini Bhardwaj, has world championships experience, all the U.S. women looked confident and secure. Bhardwaj, a 1997 Worlds competitor, made a strong return (despite a large welt on her forehead from a bad crash), showing a new double layout, punch front on floor exercise.
U.S. national champion Tasha Schwikert and national runner up Tabitha Yim also looked in good shape and ready for competition, with the latter receiving a hearty audience response to her dramatic floor routine.
Highlighting Friday morning's podium training was the performance of a reinvigorated Yevgenia Kuznetsova, formerly of Russia but now competing for Bulgaria. The four-member Bulgarian squad was led by Kuznetsova, a 1996 Russian Olympian and member of three Russian world teams (1995, 1997, and 1999), who is competing in her first major competition for Bulgaria since moving to the country this year. Kuznetsova, the 1998 European balance beam champion, performed beautifully on beam and on floor exercise, where she tumbled a piked full-in, 2 1/2 twist to punch layout-front-full, and triple twist.
Also performing well-choreographed floor routines in podium training were Canada's Kate Richardson and Crystal Gilmore, though both gymnasts struggled to land their tumbling.
In the first afternoon session, a seven-member Ukrainian team trained inconsistently but showed a high level of difficulty. 2000 Junior European medallist Irina Yarotskaya trained bars and beam only, skipping vault due to a heavily taped right ankle. Olga Roschupkina, 1999 World Championships balance beam bronze medallist, appeared in better shape than she had earlier this year and trained well on all events. On floor, Natalia Serobaba attempted a layout front punch double front pass.
IG Online will continue to report from Ghent, so check back for updates.
The gymnasts have been training all week at halls at the Flanders Expo, and today was the first of two days of podium training at the actual competition site, the Flanders Sports Arena.
Though Russia's Yevgeny Podgorny suffered an injury (extent unknown at this time) when he fell on high bar today, most of the teams trained successfully. A few highlights of the afternoon session included the strong American and Ukrainian teams, who both performed difficult routines consistently. The Ukrainian team, coached by 1989 World Champion Igor Korobchinsky, looked especially strong on floor exercise. Individual highlights came from previous world and Olympic medallists Ivan Ivankov (BLR), Jordan Jovtchev (BUL), Igors Vihrovs (LAT) and Jesus Carballo (ESP), who all looked prepared and worked aggressively. 1996 Olympic floor exercise champion Ioannis Melissanidis skipped floor but trained on vault, working Yurchenko and Tsukahara timers only instead of competition vaults.
The women's podium training begins Friday at 9:00 am. Romania, the defending team champions, have been one of the most consistent teams at the training gym this week. The American women, who hope to reply on consistency rather than high start values in their quest for a team medal, have also looked very strong in training. The Russian team has struggled in practice with Olympic gold medallist Yelena Zamolodchikova apparently suffering from injury. Her leg swollen and wrapped, Zamolodchikova has trained diligently nonetheless. Zamolodchikova's teammate Lyudmila Yezhova, a bars and beam specialist, has trained very consistently on those two events. Yekaterina Privalova (RUS) has submitted a new element to the WTC (Women's Technical Committee): a Stalder with legs together and it has reportedly received a "D" rating. Additionally, Mexico's Brenda Magaña has submitted a triple back dismount from uneven bars, which has received a rating of "Super E."
"My athletic career has been defined by my Olympic experience, and I hope to be able to make a contribution to the IOC," she said. The next IOC board elections will probably take place in 2003.
Comaneci said she is eager to meet with new IOC President Jacques Rogge, when she attends the World Championships that begin this weekend in Ghent, Belgium. "Ghent is Mr. Rogges' hometown, and I am glad that he will be able to attend the competition finals," Comaneci said.
IG Online and IG magazine will be in Ghent covering the World Championships, so check back here for updates.
Read more about Comaneci in IG Online's Legends profile on her, by clicking here.
At the time of the crash, Sopper was en route from Washington, D.C. (where she had been working as a lawyer) to California, to begin her one-year coaching assignment at UCSB. She had planned to revitalize and restore the program that had officially been dropped by the university.
Marion Kminek, Sopper's mother, met recently with UCSB athletic director Gary Cunningham and university fundraiser Gil Picciotto to discuss saving the program. Although the university originally said the termination of the program was non-negotiable, Kminek said Cunningham and Picciotto finally agreed to let her try to raise the $5 million (half of which must be committed by March 2002) necessary to maintain the program.
"They were very cooperative," Kminek told IG.
Picciotto commended Kminek's efforts to restore the UCSB women's gymnastics program in the memory of her daughter.
"Should Marion be able to be the catalyst for support at that level, many of the hurdles that face UCSB athletics as a whole will be removed," said Picciotto, "and the department will be able to rethink its position on its ability to sponsor women's gymnastics."
All donations will be made to:
Mari-Rae Sopper Gymnastics Memorial Fund
c/o Harris Bank of Palatine
50 N. Brockway
Palatine, IL 60067
Attn: Eric Eimen
As reported last week, China will send a "B" men's team and only one woman to the World Championships, which will begin next weekend in Ghent. Instead, the country's top gymnasts are preparing for the Chinese National Games, which will be held next month.
"It's very interesting to know that the National Games are more important than the World Championships or World Cup," the source explained. "The reason is that, since each national team member has his or her home team, they will return to their home provinces to represent their home teams. And if they win, the bonus and other material rewards are even more generous than the World Championships and the Olympics. Whenever they are in the year of the National Games, the world championships of individual sports such as track and field, swimming and gymnastics will suffer."
Earlier this year, China entered an inferior team at the World Track and Field Championships, according to the source. The team's mediocre results there were "because most of the top Chinese athletes were not willing to represent their country, and were afraid of being injured so that they would not be able to represent their home provinces," explained the source.
In addition, sports authorities in the athletes' hometowns do not want them to compete for the country in major competitions so close to the National Games "because their victories (at the National Games) will boost the ranking of their home provinces, which will be decisive to the future of the sports authorities after the National Games," said the source. "This is quite 'Chinese,' but it's really the main reason why China is sending only a young team to Belgium."
IG will be reporting from Ghent, so check back here for updates.
For an index of IG Online and IG magazine's coverage of Chinese gymnastics,
"The team has been very cohesive, so although we have some inexperienced girls, they are working well together," said Liz Chetkovich, head of gymnastics at the Western Australian Institute of Sport, where team member Allana Slater trains.
Slater placed ninth all-around at the last World Championships, held in Tianjin in 1999. There, the Australian women placed fifth - their best team finish in Worlds Championships history.
"Allana has found her 'old self' again, and has had a very good preparation for Worlds," Chetkovich told IG.
Reigning Australian national all-around champion Jacqui Dunn is also expected to lead the team in Ghent.
IG will be reporting from Ghent, so check back here for updates.
Kabayeva, winner of yesterday's all-around title, won three more gold medals tonight, taking the titles on rope, ball, and clubs. Kabayeva nearly swept the golds here in Madrid, but when she dropped the hoop at the end of her routine in today's final she ceded that title to teammate Chaschina by .05. On Friday, Russia also took the gold medal in the team competition.
Chaschina won the hoop gold and three silvers behind Kabayeva tonight. In addition, she was awarded the "Prize for Elegance" by Swiss watchmaker and FIG sponsor Longines. (1997 World Champion Yelena Vitrichenko, FIG President Bruno Grandi Paloma del R�o of Spanish television station TVE, and Longines president Walter von Kaenel were the jury who decided the winner of the prize, which is awarded to the competition's most elegant gymnast.)
Ukrainian Tamara Yerofeyeva, yesterday's bronze medallist in the all-around competition, won a second bronze tonight when she placed third with the rope. The remaining three bronzes went to Bulgaria's Peycheva, who returned her country to the World Championships medal stand for the first time since 1996.
The FIG announced today that Ukrainian judge Tatiana Litovko has been expelled from the FIG's select pool of judges, having committed what the FIG called "serious judging mistakes." "The Technical Committee, chaired by Mrs. Egle Abruzzini (ITA) has analysed all judges marks given to Tamara Yerofeyeva (UKR), ranked 3rd and Simona Peycheva (BUL), ranked 4th and came to the conclusion that serious judging errors were made," read an FIG press statement. An appeal by Litovko was rejected.
In addition to the red-carded Litovko, three other judges - Bulgarian Giurka Gancheva, Great Britain's Heather Richards and France's Betty Lhoste - received warnings in the form of yellow cards. A second yellow card is equal to a red card, which means automatic expulsion.
"With the exception of the above mentioned case," continued the FIG statement, "the judges present in Madrid have made an excellent job, proving that the new system put in place by the FIG is working and respects the spirit of fair play and the code of ethics. The FIG and its President Bruno Grandi are proud of this attitude. The exemplary sanctions underline the willingness of the FIG in its fight against biased judging and corruption among the judges and to preserve the spirit of fair play and ethics to the benefit of the gymnasts."
World Rhythmic Gymnastics Championships
Madrid, Spain
Rope Final
1. Alina Kabayeva RUS 27.925
2. Irina Chaschina RUS 27.250
3. Tamara Yerofeyeva UKR 26.025
4. Simona Peycheva BUL 25.950
5. Anna Bessonova UKR 25.700
6. Yelena Tkachenko BLR 25.000
7. Elizabeth Paiseva BUL 24.575
8. Inna Zhukova BLR 24.400
Hoop Final
1. Irina Chaschina RUS 27.500
2. Alina Kabayeva RUS 27.450
3. Simona Peycheva BUL 26.175
4. Anna Bessonova UKR 25.900
5. Tamara Yerofeyeva UKR 25.700
6. Almudena Cid ESP 24.750
7. Yelena Tkachenko BLR 24.400
8. Inna Zhukova BLR 24.225
Ball Final
1. Alina Kabayeva RUS 27.950
2. Irina Chaschina RUS 27.275
3. Simona Peycheva BUL 26.625
4. Anna Bessonova UKR 26.100
5. Tamara Yerofeyeva UKR 25.700
6. Yelena Tkachenko BLR 25.250
7. Laura Zacchilli ITA 24.700
8. Inna Zhukova BLR 23.600
Clubs Final
1. Alina Kabayeva RUS 28.375
2. Irina Chaschina RUS 27.525
3. Simona Peycheva BUL 27.275
4. Yelena Tkachenko BLR 25.725
5. Tamara Yerofeyeva UKR 25.600
6. Anna Bessonova UKR 25.325
7. Alyona Osyadovskaya BLR 25.325
8. Elizabeth Paiseva BUL 25.000
Click here for IG Online's special event coverage of the 2001 World Rhythmic Gymnastics Championships.
The vocal Spanish audience, made up largely of teenage girls, have been packing the hall at Parc Juan Carlos I since Thursday, when the World Championships began. Their faces painted with the red and yellow flag of Spain, they wave flags and banners and stamp their feet in rhythm. Dozens of stuffed animals and roses are thrown onto the mat when the audience is pleased with a routine - a practice which continues despite announcements saying throwing objects is forbidden. Cheering and chanting, their antics make them likely the wildest gymnastics audience in the world.
With their chanting and rhythmic foot stamping, the noise level steadily builds until it explodes when their favorite gymnasts walk out onto the floor. Alina Kabayeva, who has won the hearts of rhythmic fans around the world, owns the Spanish crowd here in Madrid. On her way to winning her second all-around title Saturday, Kabayeva responded to the screaming audience after her routines, prancing and flirting.
But even surpassing the popularity of stars Kabayeva and Irina Chaschina is that of the home Spanish team, led by the crowd's beloved Almudena Cid. During Friday's team finals (which was held in two separate stands simultaneously in the same hall), throngs of Spanish fans went sprinting across the hall to watch their team perform their final event. With the seats already taken, hysterical fans climbed the stands from the outside and sat on each others' shoulders to get a glimpse of the action.
The crowd appears to be as knowledgable about rhythmic as they are rabid about it. The audience members, many wearing t-shirts with the names of their own home gyms, respond not just to dramatic throws and catches but to simpler moves as well. The exquisite turns of Ukrainian Tamara Yerofeyeva, performed on the tips of her toes, elicited deafening screams yesterday.
The affection of the crowd is not just reserved for competing gymnasts. One more than one occasion, the audience chanted the name of former star Larisa Lukyanenko, now a coach for Belarus, until Lukyanenko responded with a wave. Recently retired gymnasts Eva Serrano (FRA) and Yelena Vitrichenko (UKR) have been similarily serenaded.
FIG President Grandi, touched by the audience interaction, thanked them after Saturday's all-around final. Their record-level antics and passion made them not just an audience but participants, said Grandi, calling them a "show within a show."
Kabayeva began with a mistake on rope in the first rotation, eliciting gasps from the audience when she fumbled with the apparatus, scoring 27.850. After she nailed her routine with the hoop - the apparatus she dropped at the 2000 Olympics - Kabayeva performed an impromptu victory dance for the adoring Spanish crowd.
Kabayeva's golden performance also included a 28.250 on ball (where she pumped her fist triumphantly after her final pose) and a 28.550 with clubs in the fourth rotation. Though she didn't perform the spectacular throws and catches Chaschina had done with the clubs, her routine to Russian folk music nevertheless brought the audience (which included her parents) to its feet in ovation.
"Of course I'm very happy with my performance here, but I still have not forgotten the Olympic Games in Sydney," said a thrilled Kabayeva, when asked if she still thought about her bronze medal-winning performance at last year's Olympics. "I again thank my coaches, Irina Viner and Vera Shatalina."
Chaschina, Kabayeva's chief rival for the title, took the first round lead with a strong hoop routine, but committed errors on two events. Looking less sharp than she had in the previous days of competition in Madrid, Chaschina appeared to stumble out of several turns during her rope and ball routines, scoring 26.850 and 26.625 respectively.
With the gold and silver medals spoken for by the dominant Russian duo, the competition for the bronze medal was hotly contested between Bulgarian Simona Peycheva and Ukrainian Tamara Yerofeyeva. In third place after three rotations, Peycheva lost the medal by .075 when her ball routine was given 25.550 and Yerofeyeva's rope routine received 27.125.
Despite extensive efforts by the FIG to curb biased judging in rhythmic gymnastics, the all-around scoring in Madrid was not without controversy. In the third rotation, one judge gave Yerofeyeva's clubs routine a 7.70 in artistic value but marked Peycheva's clubs routine as 9.00 in that category; in the fourth and final rotation, another judge suspiciously gave Peycheva's ball routine a 7.70 for artistic value while awarding Yerofeyeva's rope routine a 9.05 in artistic value. (The nationalities of individual judges were blocked out on the official results; instead, all judges were simply denoted as being from the FIG.)
"Generally I'm very satisfied," said FIG President Bruno Grandi, when asked about the judging. "But after every major FIG event there is always an analysis [of the scores] in order to make improvements."
The competition concludes Sunday with the event finals.
World Rhythmic Gymnastics Championships
Madrid, Spain
All-Around Final (top 12)
1. Alina Kabayeva RUS 113.025
2. Irina Chaschina RUS 109.750
3. Tamara Yerofeyeva UKR 106.225
4. Simona Peycheva BUL 106.150
5. Anna Bessonova UKR 103.575
6. Yelena Tkachenko BLR 101.200
7. Elizabeth Paiseva BUL 96.875
8. Inna Zhukova BLR 96.850
9. Almudena Cid ESP 96.775
10. Aliya Yussupova KAZ 96.700
11. Zhong Ling CHN 96.250
12. Laura Zacchili ITA 95.225
The Bulgarian team finished fourth yesterday at the World Rhythmic Gymnastics Championships in Madrid, missing the bronze medal by a little over half a point. Dukova, disappointed that her team was not on the podium, told IG yesterday she felt the judges have forgotten how to put Bulgarian rhythmic gymnasts on the medal stand.
The Bulgarian rhythmic program once dominated the sport, sweeping the all-around medals at the 1981, 1985, and 1987 World Championships. Bulgarian rhythmic has suffered with cuts in funding and the departures of many top coaches, and Russia, Ukraine, and Belarus have have won all the gold medals at World Championships and Olympic Games since 1995. 1995 was the last time a Bulgarian gymnast won an individual gold medal at the World Championships, when Bulgarian Maria Petrova won her third consecutive all-around title.
Dukova said she hopes Peycheva will lead a new generation of Bulgarian gymnasts capable of rivaling the gymnasts from the former Soviet Union for gold. "We all realize that our only chance is to be consistent," she said of the Bulgarian game plan. "If next year we can present a very high-quality team, I think that sooner or later we can convince the judges that we deserve more in gymnastics."
Peycheva scored the third highest individual total in the team competition in Madrid, and will contest for a medal today in the all-around competition. When asked if she also disagrees with the results, Peycheva replied, "It's not for me to judge the judges."
Hoping Peycheva can win Bulgaria�s first individual gold since Petrova, but unhappy with the scores the Bulgarian team has received in Spain, Dukova told IG, "I don't think it will happen in Madrid at these World Championships."
With a score of 275.900, team Russia led a former-Soviet sweep of the medals, sharing the podium with Ukraine and Belarus. Host nation Spain finished fifth.
Kabayeva rejoiced in victory, and said her focus remains on the continuing competition in Madrid. "I'm very glad, and I want to thank our coach Irina Viner," said Kabayeva. "But Irina [Chaschina] and I cannot relax yet, because tomorrow and the day after tomorrow we continue the competition."
Kabayeva qualified first to the all-around and scored the highest in three of the four events. Kabayeva anchored her Russian team on all the apparatus but clubs, where Chaschina took the highest score. Kabayeva managed to take the top score on rope despite struggling with the apparatus, visibly stumbling several times.
Ukraine, fourth after the first day of competition, moved up two spots today to claim the silver medal. When asked if they were nervous about finishing outside of the medals, team captain Tamara Yerofeyeva said, "We don't think about medals, we only think about doing the best we can."
Belarus swiped the bronze medal from a bitter Bulgarian team by a margin of .525, despite the efforts of Bulgaria's Simona Peycheva, who was the third highest scorer of the team competition. Peycheva's coach, Marietta Dukova, was disappointed in the results, saying she felt her team belonged among the medallists. "I think that we deserved to win a medal," a disheartened Dukova told IG. "I also think that, unfortunately, the judges are out of habit of putting Bulgarian rhythmic gymnasts on the podium."
Fifth-place Spain was led by two-time Olympian Almudena Cid, who told IG she was happy for her team but disappointed in her own performance today. Cid erred in both her routines today, dropping the clubs in the last rotation and knocking the ball out of the area when she failed to catch it between her legs after consecutive rolls. "I think we did well," she said. "As for me, my performance was not as good today but I hope to do better tomorrow."
Speaking after her clubs routine, Cid was frustrated but pragmatic. "I am very angry because clubs is a routine I have worked on a lot, and that was an element I don't normally miss. I think it was a bit of bad luck; had I missed an element that I sometimes miss in practice I would not be so upset."
A maximum of two gymnasts from each country can advance to the all-around and apparatus finals. The scores of Kabayeva and Chaschina so far in Madrid hint that the only color medal available to other gymnasts will be bronze. With Saturday's all-around finals set up as a Russian duel, Chaschina was asked if she could dethrone the reigning world champ.
"My goal is not to win," said Chaschina, "but just to do everything I'm capable of, and make my coaches proud of me."
Team Competition Finals Results (top 12)
1. Russia 275.900
2. Ukraine 258.875
3. Belarus 254.500
4. Bulgaria 253.975
5. Spain 235.300
6. Kazakhstan 229.375
7. Greece 226.575
8. China 225.350
9. Italy 225.150
10. Great Britain 219.475
11. France 216.425
12. Canada 215.950
Individual Rankings (total of top three scores)
1. Alina Kabayeva RUS 84.775
2. Irina Chaschina RUS 83.325
3. Simona Peycheva BUL 79.325
4. Lyaisan Utyasheva RUS 78.825
5. Tamara Yerofeyeva UKR 78.600
6. Anna Bessonova UKR 78.300
7. Yelena Tkachenko BLR 77.600
8. Inna Zhukova BLR 76.550
9. Alyona Osyadovskaya BLR 75.500
10. Elizabeth Paiseva BUL 75.050
11. Almudena Cid ESP 74.725
12. Yuliana Naidenova BUL 74.375
Click here for IG Online's special event coverage of the 2001 World Rhythmic Gymnastics Championships.
However, Kryukov was not among the world team members announced by Russian Gymnastics Federation president Leonid Arkayev on Wednesday. At a press conference held at Russia's Round Lake national training center, Arkayev said Russia's world team will consist of Alexei Bondarenko, Georgy Grebenkov, Yevgeny Krylov, Alexei Nemov, Yevgeny Podgorny, and Yuri Tikhonovsky. According to Arkayev, the gymnasts who will compete all events in the team preliminaries in Ghent will be Bondarenko, Podgorny, and Tikhonovsky, while 2000 Olympic all-around champion Nemov will compete only four.
Though China, the four-time defending team world champions in men's gymnastics, has stated its intentions to send only a "B" men's squad, Arkayev told reporters he is concentrating on the women's team.
"Even Arkayev is not thinking about the gold medal in the men's team competition," said IG's source, who attended the press conference. "He will try to fight in the women's competition."
The women's team was announced as Svetlana Khorkina, Yekaterina Privalova, Lyudmila Yezhova, Yelena Zamolodchikova, Maria Zasypkina, and Natalia Ziganshina. Khorkina, Zamolodchikova, and Ziganshina will compete all events in team preliminaries.
IG Online and IG Magazine will be reporting from Ghent, so check back here for updates.
For an index of IG Online and IG magazine's coverage of Russian gymnastics, click here.
Expected to lead the American team in Ghent are reigning national all-around champions Tasha Schwikert and Sean Townsend.
Meanwhile, Japan, which had previously withdrawn its team from the Rhythmic Worlds in Madrid, withdrew its artistic team from Ghent. "The Gymnastics Association announced today that the executive committee had decided to cancel the participation in World Artistic Gymnastics Championships in Ghent, Belgium," read a statement on the federation's official website.
IG Online and IG Magazine will be reporting from Ghent, so check back here for updates.
Kabayeva took the highest two scores of the day, catapulting Russia to the top of the standings at the halfway mark of the team competition. With her difficult routines appreciated by both crowd and judges alike, Kabayeva looks set to defend her all-around world title on Saturday. Her teammates Irina Chaschina and Lyaisan Utyasheva were ranked second and fifth respectively as individuals.
Behind the dominant Russian team - ten points back - is the team from Belarus, led by Yelena Tkachenko. In third is the Bulgarian team, which is relying on the strong scores of Simona Peycheva, who is currently ranked third individually.
Ukraine, .325 behind Bulgaria, is currently in fourth place. Ukraine's top scorer was veteran Tamara Yerofeyeva, while Anna Bessonova suffered a break with her rope routine, failing to clear the rope on a jump.
Home team Spain trailed Ukraine in fifth place, with Almudena Cid in eleventh as an individual.
The team competition concludes Friday in Madrid, and serves as the qualification for Saturday's all-around competition and Sunday's event finals (scores do not carry over).
Team Competition (top 12 teams after one day)
1. Russia 164.325
2. Belarus 154.200
3. Bulgaria 152.500
4. Ukraine 152.175
5. Spain 141.175
6. Italy 137.250
7. Kazakhstan 135.375
8. Greece 135.250
9. Canada 131.600
10. Great Britain 131.425
11. France 131.025
12. China 130.900
Individual Rankings (top 12 after one day)
1. Alina Kabayeva RUS 56.850
2. Irina Chaschina RUS 55.225
3. Simona Peycheva BUL 52.975
4. Yelena Tkachenko BLR 52.500
5. Lyaisan Utyasheva RUS 52.250
6. Tamara Yerofeyeva UKR 51.875
7. Inna Zhukova BLR 51.300
8. Anna Bessonova UKR 51.050
9. Alyona Osyadovskaya BLR 50.400
10. Elizabeth Paiseva BUL 50.200
11. Almudena Cid ESP 49.975
12. Laura Zacchilli ITA 49.400
Click here for IG Online's special event coverage of the 2001 World Rhythmic Gymnastics Championships.
CGA chief Zhang Jian explained that the top gymnasts were tired after a long season of competitions, including the East Asian Games, World University Games and Goodwill Games. Zhang advised that the Chinese team preferred to concentrate their efforts on the National Games which follow Ghent, according to the source.
Instead, China intends to send a "B" men's team and only one female gymnast, Sun Xiaojiao, to Ghent.
Carballo said he is looking to Moro, 17, to take the role from Martinez, who seriously injured her knee earlier this year and is beginning rehabilitation after surgery. According to Carballo, Esther Moya, who finished fourth on floor exercise at the 2000 Olympic Games, is not in top shape and may not compete that apparatus in Ghent.
At a workout at the Spanish national team training center in Madrid today, Moro appeared in excellent shape; she worked double-twisting Yurchenko vaults on the new vaulting table, and a new balance beam combination of back handspring, layout stepout, Rulfova. Moro said her goals for Ghent are good results from her team, as well as a strong all-around showing for herself.
The Spanish women's team will consist of Moro, Moya, Alba Planas, Anna Parera, Marta Cusido, and Elena Gomez.
Women's assistant coach Almudena San José said she couldn't predict where her team would finish in Belgium. "I don't know what to expect," said San José. "This is a post-Olympic year, and a lot of our older girls are a little injured."
Carballo, whose son Jesus Carballo Jr. is the reigning world champion on high bar, said he feels the FIG should have considered holding individual World Championships this year instead of having a full team competition. "I think most teams aren't ready for Worlds," he said.
Representing the Spanish men's team will be Carballo Jr., his younger brother Manuel Carballo, Victor Cano, Alex Barrenechea, Saul Cofino, Andreu Vivo, and Oriol Combarros. Absent from Ghent will be 2000 Olympic vaulting gold medallist Gervasio Deferr, who is suffering from a shoulder injury.
IG will be reporting from the World Rhythmic Championships that begin tomorrow in Madrid, as well as the World Artistic Championships in Ghent, so check back for updates.
Read more on the Spanish gymnastics program in a future issue of International Gymnast Magazine.
"Romania will participate with full teams for men and women," said Adrian Stoica, Secretary-General of the Romanian Gymnastics Federation, and President of the FIG Men's Technical Committee. "Life is complicated and not nice sometimes, but must go on."
IG will be reporting from the World Rhythmic Championships that begin Thursday in Madrid, as well as the World Artistic Championships in Ghent, so check back for updates.
For an index of IG Online and IG magazine's coverage of Romanian gymnastics, click here.
"The Australian teams will be competing in Ghent unless there are any major developments between now and next week when they depart Australia," said Jane Allen, Chief Executive Officer of the Australian Gymnastics Federation.
Expected to lead the Australians are reigning all-around national champions Jacqui Dunn and Philippe Rizzo, and 2000 Olympian Allana Slater
As reported on IG Online on Saturday, concern for athletes' safety was among the reasons for USA Gymnastics' withdrawal from the World Rhythmic Championships that begin October 18 in Madrid.
IG will be reporting from Madrid and Ghent, so check back here for updates.
Read about Rizzo as IG Online's Spotlight Gymnast for October 2001 by clicking here; and in a profile in a future issue of IG magazine.
The U.S. is still planning on sending a delegation to the artistic World Championships in Ghent. American coach Tim Garrison told IG earlier this week that "there was a renewed sense of patriotism" among the coaches and athletes. Garrison, who coaches World Championships team member Rachel Tidd, attended a training camp with Tidd at Bela Karolyi's ranch prior to the recent Pan American Gymnastics Union championships.
"The U.S. team is totally pulling together," observed Garrison. "Everybody was feeling that at the camp. The kids all pulled together, and the coaches were doing the same thing. Everybody seemed to be working for the best for the team. It didn't seem like anyone was looking out just for themselves."
The U.S. also cancelled planned training camps in Belgium and France for its artistic teams, which were scheduled to be held prior the World Championships in Ghent.
Inge Doens of the Belgian Gymnastics Federation told IG today that extra security precautions will be taken. "Belgian authorities are working hard on the safety of this event," said Doens. "There is permanent security for each delegation. The competition hall will be screened completely."
Watch for more updates on the World Gymnastics Championships, direct from Madrid and Ghent, here on IG Online.
According to a USA Gymnastics statement, Deci was training in Colorado at the Junior National Team Training Camp. While training pommel horse on October 11, Deci collapsed. He was taken to the hospital where efforts to resuscitate him failed. An autopsy is scheduled to be performed today.
"Ricky was a talented and promising young athlete who was full of life,"
said Dennis McIntyre, U.S. Junior National Team Coordinator. "He was a joy to be around."
"This is a real tragedy and loss for the USA Gymnastics family," said USA Gymnastics President Bob Colarossi in a statement. "Our thoughts and prayers are with
Ricky's family and friends at this difficult time."
"Russia has it all at the moment - a Queen: Alina Kabayeva, a Princess: Irina Chaschina, and a New Weapon: Lyaisan Utyasheva," said Marinova-Atkinson. "The quality of the Russian routines improved a lot after Sydney 2000; this became apparent in their scores wherever they have competed over the 2001 season. All they need is to be reasonably stable."
Marinova-Atkinson, a native of Bulgaria who now resides in Great Britain, said few nations will pose a threat to the Russians in Madrid, where the World Championships will be held October 18-21.
"As a class, closest to Russia is Ukraine," said Marinova-Atkinson, who earned a gold medal with the Bulgarian group at the 1971 World Rhythmic Championships in Havana. "Belarus will struggle without Yulia Raskina. The Bulgarians, with Simona Peycheva in particular, will show a stormy development of their new generation."
Like artistic gymnastics in 2001, a new version of the Code of Points is in place for rhythmic gymnastics. "The whole approach to evaluating routines and even the maximum score a gymnast can achieve have changed," explained Marinova-Atkinson. "The ultimate difficulty according to the old Code was 'D'. Now we see 'E' and even 'F' and 'G' elements."
Controversial scoring at the 2000 European Rhythmic Championships, held in Zaragoza, Spain, led to year-long suspensions for several judges. In an effort to prevent further judging scandals, a rigorous examination for judges was held in Moutier, Switzerland, this past July. From that exam, a selected group of judges was formed; only these judges will be allowed to judge at official FIG-sanctioned events.
"I don't expect any of those who were nominated to judge in Madrid to be as bold as many judges were in Zaragoza [in 2000]," said Marinova-Atkinson. "There might be some problems, but such problems as [seen] in Zaragoza are not likely to be seen in Madrid. The judges should have learned their lesson by now."
Watch for coverage of the 2001 World Rhythmic Championships, direct from Madrid, here on IG Online.
For a complete index of IG Online and IG magazine's coverage of rhythmic gymnastics, click here.
At last mmonth'sRomanian National Championships, Raducan was bumped to third place behind first-year seniors Sabina Cojocar and Silvia Stroescu, who tied for the gold medal.
1976 Romanian Olympian Anca Grigoras, now a Brevet judge, told IG it will be Raducan who fulfills the role as team leader for the young squad. Raducan, who turned 18 on September 30, is the oldest and most experienced member of the Romanian team, which also includes 15-year-old Carmen Ionescu, 17-year-olds Andreea Ulmeanu and Loredana Boboc, and 16-year-olds Stroescu and Cojocar (who turns 16 on October 23). Monica Sabou, 16, is the alternate.
Romania will attempt to win its fifth consecutive team title at the 2001 World Championships, which begin October 28 in Ghent, Belgium. It will be difficult to predict the outcome, says Grigoras. "This world championships will be an experiment with the new Code of Points," she said. "Like everybody else, we want to stay on the podium."
Watch for coverage of the 2001 World Championships from Ghent here on IG Online.
Read a feature on Sabina Cojocar in the November issue of International Gymnast Magazine. For a complete index of IG Online and IG magazine's coverage of Romanian gymnastics, click here.
López Rios, three-time winner of the larger Pan American Games, scored 55.475 to win the gold over his teammate, Charles Tamayo León (53.900 ). Winning the bronze was Puerto Rican Luis Vargas (53.875). The Cuban men were also victorious in the team competition, topping the USA and Puerto Rico.
The American women dominated the competition, winning the team title and finishing in the top three places in the all-around. Schwikert (37.765) led the American sweep of the all-around medals, finishing ahead of silver medallists Mohini Bhardwaj (37.398) and bronze medallist Tabitha Yim (37.165).
Pan American Union Championships
Cancun, Mexico
Women's Team Competition
1. USA 112.862
2. Brazil 111.362
3. Cuba 107.798
4. Mexico 106.629
5. Venezuela 105.596
6. Argentina 105.547
7. Canada 101.678
Women's All-Around
1. Tasha Schwikert USA 37.765
2. Mohini Bhardwaj USA 37.398
3. Tabitha Yim USA 37.165
4. Daiane Dos Santos BRA 36.898
5. Daniele Hypolito BRA 36.833
6. Heine Araujo BRA 36.382
7. Katie Heenan USA 36.350
8. Camila Comin BRA 36.149
9. Janerki De La Pena Zamora CUB 36.016
10. Eddylin Zabaleta VEN 35.782
Men's Team Competition
1. Cuba 163.625
2. USA 158.900
3. Puerto Ric 156.175
4. Brazil 154.975
5. Venezuela 154.250
6. Colombia 150.900
Men's All-Around
1. Eric López Rios CUB 55.475
2. Charles Tamayo León CUB 53.900
3. Luis Vargas PUR 53.875
4. Guard Young USA 53.150
5. Jorge Giraldo COL 52.800
6. Todd Thornton USA 52.000
7. Michel Conceicao BRA 51.950
8. Alexander Jeltkov CAN 51.700
9. Carycel Briceno VEN 51.700
10. Michel Brito Ferre CUB 51.600
"I have worked on this new vault since April," said the 28-year-old Zimmermann, who has won the Austrian all-around title six times. "First I tried to do the normal Roche (double front) with the half turn at the end of the jump, but I had a better feeling with the half turn after the first somersault. So, this new jump was born."
Zimmermann said he performed the vault at the Swiss Championships two weeks ago (where he competed as a guest), and again at last weekend's tri-meet among Austria, Czech Republic and Slovakia. At the tri-meet, he scored 9.25 on the vault and won the all-around.
"I knew that it would be possible for me to do this new vault, since I made the first one this year in April," said Zimmermann.
Zimmermann, who has competed nine times at the World Championships, plans to compete at the 2001 World Championships that begin at the end of the month in Ghent.
For an index of IG Online and IG Magazine's coverage of Austrian gymnastics, click here. | http://web.archive.org/web/20011121084826/http:/www.intlgymnast.com/news/2001/oct.html | CC-MAIN-2017-30 | refinedweb | 7,916 | 63.49 |
Argument-dependent lookup(ADL) is a protocol for looking up unqualified function names in function-call expressions.
These function call expressions include implicit function calls to overloaded operators.
The function names are looked up in the namespaces of their arguments in addition to the scopes and namespaces considered by the usual unqualified name lookup. Argument-dependent lookup makes it possible to use operators defined in a different namespace.
namespace MyNamespace{ class A {}; void f( A &a, int i) {} } int main() { MyNamespace::A a; f( a, 0 ); //calls MyNamespace::f }
The lookup of a function call to f was dependent on the argument a. The same case is applied to arguments like << and >> that are looked up in std namespace when we use things like cout, cin, endl, etc. | https://www.tutorialspoint.com/What-is-Argument-Dependent-Lookup-Koenig-Lookup-in-Cplusplus | CC-MAIN-2020-50 | refinedweb | 128 | 50.87 |
Teleport is an open source, identity-aware, access proxy with an integrated certificate authority. People have been using teleport for ssh-access, Kubernetes clusters and with Teleport 6.0 you get Database access as well (Postgress and MySQL).
In this tutorial, I will show you how you can do it all from scratch for a self-hosted MySQL Database(I will show the database install as well).
Prerequisites: 2 Ubuntu 20.04 instances with sudo access.
I have 2 machines called teleport and database
3 weeks back I wrote a book “Learn CKS Scenarios” on Gumroad..
Docker Meetup 16th Jan: Kickstart Your 2020 Container Journey with Docker & Kubernetes + Kubernetes101 Workshop
Year Begining I along with other community members organized the biggest Docker…
Originally posted on my website
In this post, we will discuss a tool name “Kubevious”
Visualizing Kubernetes is something that everyone wants, the more good the visualization, the more it gets adopted by the community. Tools that help to view/debug the issues/configurations right in front of the screen make the life of dev/ops people easy.
There are Different Tools as of today that do the visualization, but I found Kubevious to be different. Along with the visualizations, it also shows the misconfigured labels for the pods-services, instantly shows the RBAC roles/permissions for the service accounts. Sounds Exciting? …
Today I will be sharing some insights into working with Shipa.
So Shipa is a platform mainly built for the developers so that they can focus more on writing code and less on the infrastructure. The main idea IMO is to make developers' life easy and making their apps run on the best in class kubernetes clusters.
One can associate the Kubernetes clusters with ships using the following guide:
learn.shipa.io
Once the cluster is added it shows up in the dashboard for the shipa instance and you can have an overview of all the cluster/apps associated.
Dashboard :
Dashboard view if…
Came across a GitHub repository implemented by the awesome folks at Sighup.IO for managing user permissions for Kubernetes cluster easily via web UI.
GitHub Repo :
With Permission Manager, you can create users, assign namespaces/permissions, and distribute Kubeconfig YAML files via a nice&easy web UI.
The project works on the concept of templates that you can create and then use that template for different users.Template is directly proportional to clusterrole.
In rder to create a new template you need to defile a clusterrole with prefix
template-namespaces-resources__. The default template are present in the k8s/k8s-seeds directory.
Example template:
apiVersion: rbac.authorization.k8s.io/v1
kind…
A Quick overview and install in less than 5 minutes
Definition From the Docs : one of the recent projects by VMware that aims to simplify the kubernetes view for developers. Now the developers would be able to see what all is happening…
K3s is an open-source, lightweight Kubernetes distribution by Rancher that was introduced this year and has gained huge popularity. If you’re not familiar with it, check out this post on k3s vs k8s by Andy Jeffries, CTO at Civo. People not only like the concept behind it, but also the awesome work that the team has done to strip down the heavy Kubernetes distribution to a minimal level. Though k3s started as a POC project for local Kubernetes development, its development has led people to use it even at a production level.
Official GitRepo:
Seeing the popularity of k3s… | https://saiyampathak.medium.com/?source=post_page-----a38469535955-------------------------------- | CC-MAIN-2021-25 | refinedweb | 581 | 52.8 |
ubuntu/+source/lintian:applied/ubuntu/utopic-proposed
- Git
- lp:ubuntu/+source/lintian
- applied/ubuntu/utopic-proposed
- Get this branch:
- git clone -b applied/ubuntu/utopic-proposed
Branch merges
Related source package recipes
Related snap packages
Branch information
- Name:
- applied/ubuntu/utopic-proposed
- Repository:
- lp:ubuntu/+source/lintian
Recent commits
- d1480e6... by Stéphane Graber on 2014-10-20
Import patches-applied version 2.5.27ubuntu2 to applied/
ubuntu/ utopic- proposed
Imported using git-ubuntu import.
Changelog parent: 2a69f5a3d235771
6766bce6c5f1a1f bf3efd6e11
Unapplied parent: cfd1df24cd85b0c
38cc864a689b327 9436ab2828
New changelog entries:
* Add vivid to the list of valid Ubuntu series.
-85)
- 2034adf... by Bastien Roucariès <email address hidden> on 2014-03-25
Import patches-unapplied version 2.5.22 to debian/sid
Imported using git-ubuntu import.
Changelog parent: 50fa67cb68f634a
78cf4ef5320ab0d 3f8ab002e3
New changelog entries:
* Summary of tag changes:
+ Added:
- invalid-
restriction- label-in- source- relation
- invalid-
restriction- namespace- in-source- relation
- invalid-
restriction- term-in- source- relation
- license-
problem- gfdl-non- official- text
- license-
problem- non-free- RFC-BCP78
- privacy-
breach- google- plus
- privacy-
breach-
- restriction-
list-with- debhelper- with-conflictin g-debhelper- version
- restriction-
list-with- debhelper- without- debhelper- version
- restriction-
list-with- versioned- dpkg-dev- conflict
- restriction-
list-without- versioned- dpkg-dev- dependency
- source-is-missing
- stageX-
profile- used-but- no-binary- package- dropped
* checks/*:
+ [NT] Avoid using "I" or "we" in tag descriptions.
+ [NT] When looping over the names of binary packages,
prefer the order they are listed in the control file.
Previously they were either sorted by name or ordered
by Perl's hash iterator.
* checks/
control- file.{desc, pm}:
+ [NT] Apply patch from Johannes Schauer to validate
build-profile usage.
* checks/
control- files.pm:
+ [NT] Remove special case for udebs on empty control
files. Thanks to Cyril Brulebois for testing it.
* checks/cruft.pm:
+ [BR,NT] Optimise the GFDL check considerably in some
cases (e.g. the linux source). (Closes: #738342)
+ [BR] Factorize GFDL detection. Detect non official
wordings of GFDL invariant section. (Closes: #717916).
Fix some old false positives.
(Closes: #742260, #741212).
+ [BR] Add opentoken non official wording for GFDL
invariant section, thanks to Nicolas Boulenguez.
(Closes: #740183).
+ [BR] Detect minified js based on line length.
(Closes: #735348).
+ [BR] Detect missing sources for minified javascript, flash project,
flash files, and elf binary.
* checks/
fields. {desc,pm} :
+ [NT] Apply patch from Johannes Schauer to validate
build-profile usage. (Closes: #740607)
* checks/files.desc:
+ [BR] Raise file-name-
in-PATH- is-not- ASCII and
file-
name-in- PATH-is- not-ASCII to error
(see policy 10.10), thanks to Helmut Grohne.
(Closes: #739347)
+ [BR] Improve privacy-breach tags wording, thanks to Paul Wise.
(Closes: #738176)
* checks/
menu-format. desc:
+ [NT] Apply patch from Charles Plessy to correct an URL
in a tag reference. (Closes: #738454)
* checks/symlinks.pm:
+ [BR] Use Lintian::Data for safe symlinks list. Add
/dev/null to this list. (Closes: #740339).
* checks/systemd.pm:
+ [BR] Allow spaces arround = in service files.
(Closes: #739366).
* checks/
watch-file. {desc,pm} :
+ [BR] Allow debian/
upstream- signing- key.asc,
thanks to Nicolas Boulenguez (Closes: #736711).
+ [NT] Apply patch from Daniel Kahn Gillmor to check for
the upstream signing key in debian/upstream. Thanks to
Hideki Yamane for the bug report. (Closes: #738597)
* collection/
java-info:
+ [NT] Update the conditional using file(1) to cope with
the new output for JAR files.
* data:
+ [NT] Refresh several architecture data files against
dpkg 1.17.5. Thanks to James Hunt for the reminder.
(Closes: #735266)
+ [NT] Refresh several data files with data from sid.
* data/binary/
embedded- libs:
+ [RG] Detect embedded copies of liblivemedia, libgadu, libssh,
libssh2, freetype, nss, and nspr.
+ [RG] Adjust the detection of embedded copies of libmagic.
+ [RG] Detect embedded copies of an ancient tinyxml. Thanks to
Andreas Rönnquist for the report. (Closes: #733318)
* data/cruft/
non-free- files:
+ [BR] "id3v22-tda.mp3 considered non-free", thanks to Charlie
Smotherman (Closes: #736203).
* data/files/
privacy* :
+ [BR] Improve detection of privacy-
breach- google- cse, thanks to
Paul Wise (Closes: #739247).
+ [BR] Detect google+, thanks to Paul Wise.
(Closes: #738175).
+ [BR] Detect twitter, thanks to Paul Wise.
(Closes: #738174).
* data/scripts/
maintainer- script- bad-command:
+ [BR] Fix false positive
maintaine
r-script- should- not-use- adduser- system- without- home
due to quoting, thanks to Andreas Beckmann <email address hidden>
(Closes: #739109).
* debian/
source/ lintian- overrides:
+ [NT] Override false-positive for license checks.
* debian/
tests/control:
+ [NT] Use the new @builddeps@ from autopkgtest/2.5.5
instead of duplicating the values.
* frontend/lintian:
+ [NT] Fix a regression in argument handling after the first
non-option. This problem was introduced in 2.5.18.
+ [NT] Let --color default to "auto".
+ [NT] Discard STDERR when running git describe to guess the
version of Lintian. Avoids a warning from git tags are
absent from the repository.
* lib/Lintian/
Collect/ Source. pm:
+ [NT] Apply patch from Mathieu Parent to make "binaries" return
the package name in the same order as they are listed in the
control file. (Closes: #739671)
* lib/Lintian/
Reporting/ ResourceManager .pm:
+ [NT] New file.
* lib/Lintian/
Util.pm:
+ [NT] Extend the "Continuation line outside a paragraph" parse
error on Deb822 files with a possible suggestion for fixing
the problem.
* lib/Test/
Lintian/ Harness. pm:
+ [NT] New file - mostly for internal use during testing.
* profiles/
debian/ ftp-master- auto-reject. profile:
+ [BR] Refresh with new tags.
* reporting/config:
+ [NT] Fix typo of HARNESS_STATE_DIR config variable.
* reporting/harness:
+ [NT] Avoid writing state-cache during dry-run.
+ [NT] Add timestamps to the log output.
* reporting/
{html_reports, templates/ *.tmpl} :
+ [NT] Show the same statistics on the tag page as shown
on the tag index pages. Thanks to Guillem Jover for
the suggestion. (Closes: #738349)
+ [NT] Remove the second argument to the "head" sub in
the templates. Its value is now computed automatically
by html_reports based on the name of the output file.
+ [NT] Install "lintian.css" and all files in
"
reporting/ images" and "reporting/ resources" into
"
HTML_DIR/ resources" . These will be named after their
content to allow more aggressive public caching.
* reporting/
html_reports:
+ [NT] Link to the library API docs from the index page.
(Closes: #639974)
+ [NT] Optimise the graph generation by only calling
gnuplot twice (rather than once plus once per tag).
+ [NT] Show the number of package groups and the size
of the harness backlog on the index page.
* reporting/
{lintian. css => templates/ lintian. css.tmpl} :
+ [NT] Rename file and make it a template.
* t/runtests:
+ [NT] Cache test artifacts and reuse them in subsequent
runs. This removes the majority of the runtime
overhead of running the test suite on subsequent runs.
(Closes: #699083)
+ [NT,BR] Fix test suite issues caused by a regression
in tar 1.27. (Closes: #739744) | https://code.launchpad.net/~usd-import-team/ubuntu/+source/lintian/+git/lintian/+ref/applied/ubuntu/utopic-proposed | CC-MAIN-2019-26 | refinedweb | 1,104 | 60.21 |
46867/cannot-module-fabric-network-application-installation-wrong
Hey community,
I'm trying to follow the tutorial
When I reach the step with installing the the application with npm install and then run ls I don't see the file package-lock.json. When I do the NPM install I have also tryed writing sudo npm install since I before have seen errors with missing rights to access.
In the next step where i run node enrollAdmin I get the error Error: Cannot find module 'fabric-network'. Is there missing anything in my installation?
I'm running Mac OS Mojave v10.14.5 - node v8.9.4 - npm v5.6.0.
Best regards Jeppe
First, install grpc and run it:
$ npm install grpc
$ grpc
I try to run from the fabcar directory these two commands. After npm install grpc I get:
grpc@1.20.3 install /Users/x/x/fabric-samples/fabcar/node_modules/grpc
> node-pre-gyp install --fallback-to-build --library=static_library
node-pre-gyp WARN Using needle for node-pre-gyp https download
[grpc] Success: "/Users/x/x/fabric-samples/fabcar/node_modules/grpc/src/node/extension_binary/node-v57-darwin-x64-unknown/grpc_node.node" is installed via remote
npm WARN fabcar@1.0.0 No description
npm WARN fabcar@1.0.0 No repository field.
+ grpc@1.20.3
updated 1 package in 5.588s
This seems to be alright, since it is only warnings and it says success to the installation.
But when I'm running grpc I get:
-bash: grpc: command not found
Should I change directory to the one above, where grpc is installed?
I did a little research and found that installing grpc should be enough. Can you run
node enrollAdmin
and see if it works now?
I had the same problem. The following solution worked for me:
$ npm update
$ npm install
Thank you for your answer. But if I update npm - wouldn't I get version 9.x.x? In there requirement it says only version 8.9 is supported?
Does it matter in which folder I'm running the commands from?
Is it necessary to use sudo in front of the commands?
I managed to get it to enroll admin. I did two things and I'm not completely sure which of the commands were where the magic happend.
I did the following:
1)
$ npm install grpc
$ grpc
2)
$ npm install --python=python2.7
The second command was due to the fact that the prerequisites was python 2.7 - even though it was written for Ubuntu user only in
I hope my post can help others in the future, like you two helped me!
@Rishi: As I wrote to John, it said -bash: grpc: command not found when I tried to run grpc. So I assumed it didn't worked, but to be honest I didn't tried to run enroll admin immediately after before I ran npm install --python=python2.7.
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17 January 2012 06:02 [Source: ICIS news]
By Peh Soo Hwee
SINGAPORE (ICIS)--Spot liquidity in the northeast Asian propylene (C3) market may rise this year, as some buyers in China plan to reduce their contractual commitments given high premiums being sought by traders, market sources said on Tuesday.
Traders are asking premiums of as high as $40-50/tonne (€32-40/tonne) above the published CFR (cost and freight) northeast (NE) Asia prices for 2012 settlements, roughly double those recorded for last year’s contracts with Chinese buyers, they said.
In 2011, propylene contracts with buyers in ?xml:namespace>
“The [propylene contract] premiums are very high this year - some are asking as much as $50/tonne, which is not acceptable,” said one Chinese propylene importer.
“We are likely to buy more propylene from the spot market because it is tough to negotiate the contracts,” he added.
Traders said that volatile feedstock naphtha prices and the increased procurement costs of getting term supplies from
Some South Korean producers have locked in 2012 contracts with regional traders at a discount to CFR NE Asia prices.
But the discount is usually smaller than the freight cost, which averages around $70-80/tonne from
One Korean producer said the discount was around $20/tonne in some cases, although this could not be immediately confirmed.
This meant that traders are buying term cargoes from the producers at higher prices this year, and in turn, had had to seek higher premiums in their contract negotiations with end-users.
At midday, propylene spot prices were assessed at $1,340-1,370/tonne CFR NE Asia, up $10/tonne at the low end of the price range. Naphtha spot prices were at $946.50-949.50/tonne CFR
Producers are also keen to raise propylene prices, as cracker margins remain poor, squeezed by high feedstock naphtha prices and weak polymer demand against the backdrop of a volatile global economic climate.
Cracker margins based on naphtha feed in
This has kept operating rates among some naphtha crackers in the region at an average of 80-90% notably in
A busy cracker turnaround season in the first half of the year was also among the factors for the higher contractual premiums being sought in 2012, market sources said.
For instance, key naphtha crackers in
Honam Petrochemical will shut its 750,000 tonne/year cracker at Yeosu from 1 March to 10 April while Yeochun NCC (YNCC) will take its 578,000 tonne/year No 2 cracker in the same area off line for a turnaround from 20 March to 19 April.
Given the current stand-off among some buyers and traders, contractual negotiations could drag until late January, after the Lunar New Year holidays.
“There is a deadlock in negotiations with the buyers and we have not settled the contracts,” said one Japanese olefins trader.
($1 = €0.79) | http://www.icis.com/Articles/2012/01/17/9524297/ne-asia-c3-spot-liquidity-to-grow-on-high-contract-premiums.html | CC-MAIN-2014-42 | refinedweb | 480 | 57.84 |
Hello there.
If I have two same colored blobs, how can I detecting which one is bigger and send it's data(x,y width, height) to an arduino so it can be processed by my robot.
Have a nice day, Andrija.
Differentiating blob size
Discussion related to "under the hood" OpenMV topics.
2 posts • Page 1 of 1
- Posts: 5
- Joined: Tue Apr 03, 2018 7:57 am
- Posts: 87
- Joined: Tue May 29, 2018 4:15 am
Re: Differentiating blob size
Hopefully I can help you here.
something like this should find the biggest rect blob
something like this should find the biggest rect blob
I would image the easiest way to send this data to the Ardunio would be via UART and you would have serialize the data as a stream of 4 unsigned short int like this
Code: Select all
img = sensor.snapshot() biggest = [0,0,0,0] for blob in img.find_blobs([threshold], pixels_threshold=100, area_threshold=100, merge=True, margin=10): current = blob.rect() if current[2] * current[3] > biggest[2] * biggest[3]: biggest = current
Code: Select all
from ustruct import pack packed_data = pack('HHHH', biggest)
2 posts • Page 1 of 1
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Value Types & Datesgramsay Apr 29, 2010 5:25 AM
There isn't an option to set a date during a process with a value type.
How can a date be transferred from one object to another during a process?
Is this possible?
1. Re: Value Types & Datesaparker Apr 29, 2010 9:15 AM (in response to gramsay)
Hi Graham,
I thought I'd answered this by email, so just be sure...
You can only really do this in 7.3.x of LDSD and to do it, you need to use calculations rather than Value Type in the prrocess design.
Andy
2. Re: Value Types & Datespaul.enkelaar Jan 4, 2012 5:17 PM (in response to aparker)
Hi
I have an issue with this (v7.4), in what I thought was just a simple calculation doesn't seem to be working. Turning trace logging on isn't picking up anything either.
In the Request Management module, I have a new starter process, for new staff. There is a "Start Date" attribute for when the new staff member is starting. This parent request generates various other child requests, and so I wish to pass the "Start Date" attribute to the child requests as this is essentially when a request needs to be completed by.
My calculation looks like this (and it does have appropriate spacing, although it may not show here):
import System
static def GetAttributeValue(Request):
Value = Request.Parents.Parent._UserStartDate
return Value
I assume I have overlooked something simple here, but for the life of me I can't see what. Perhaps it is still too early in the year to be at work...
Thanks
Paul
P.S. As an aside, why is it that date/time fields can't have Value Types set like other attributes? I see there is already an ER for this -
3. Re: Value Types & DatesStu McNeill Jan 5, 2012 9:43 AM (in response to paul.enkelaar)
Paul,
You're correct that you should be able to get past the Value Type limitation via a calculation. I see you've already found the ER to rectify this
Your calculation is failing because it is trying to directly call the parent, but "Parents" is a collection so you need to always imagine there could be multiple items. You can't use Parents.Latest() in this case but this simple loop will do what you need:
Parent = null for ParentLink in Request.Parents: Parent = ParentLink.Parent if Parent == null: return null else: return Parent._UserStartDate
4. Re: Value Types & Datespaul.enkelaar Jan 5, 2012 2:30 PM (in response to Stu McNeill)
Thanks for this Stu - works like a charm.
5. Re: Value Types & DatesBricktop Jan 10, 2012 5:17 AM (in response to paul.enkelaar)
I'm rubbish at BOO! I don't suppose you have the whole code, I can replace the attribute to match what I have.
Much appreciated
6. Re: Value Types & DatesStu McNeill Jan 10, 2012 5:41 AM (in response to Bricktop)
Hi Bricktop,
The example above is the whole calculation (minus the two lines you always get at the top). In your case you'd just need to replace _UserStartDate with the name of your DateTime attribute.
Hope that helps.
7. Re: Value Types & DatesBricktop Jan 10, 2012 7:36 AM (in response to Stu McNeill)
Hi Stu,
I must have had an extra space somewhere as I was getting a couple of syntax errors. Just retried it and it seems to be happy. Many thanks for your fast response. | https://community.ivanti.com/thread/10620 | CC-MAIN-2018-39 | refinedweb | 592 | 73.58 |
Agenda
See also: IRC log, previous 2008-05-20
<Ralph> WG home page
Upcoming telecons and scribes -
Jun 03 Tom - regrets Guus
Jun 10 Guus
Jun 17 Tom
Jun 24 Guus
PROPOSED to accept minutes of the last telecon:
Ralph: are minutes complete wrt notation stuff?
Guus: resolved we accept minutes.
-- Primer (Antoine, Ed)
-- Reference (Alistair, Sean)
-- Open issues
ACTION: Ed to investigate what text could be added to primer re. concept co-ordination [recorded in] [CONTINUES]
ACTION: Guus to write primer text re: broaderGeneric and equivalence w/r/t subclass [recorded in] [CONTINUES]
ACTION: alistair and sean to add a note about irreflexivity to Reference [recorded in] [DONE]
seanb: This is being done in next working draft we publish
ACTION: Alistair to check the old namespace wrt dereferencing [recorded in] [CONTINUES]
ACTION: Antoine and Ed to add content to Primer about irreflexivity [recorded in] [CONTINUES]
ACTION: Guus and Alistair write text for Reference indicating understanding of a possible need for future patterns for n-Ary label relations [recorded in]
Guus: no need for this?
Alistair: I'm happy for us to drop this
--DROPPED
ACTION: Ralph compose intermediate pages for and to inform readers of the paths to the old and new SKOS documents [recorded in] [CONTINUES]
ACTION: Sean and Alistair to send a file for the namespace [recorded in] [CONTINUES]
<seanb> See ->
seanb: I'm serving vocabularies on my own machine. You can look at this to see what you'll get for SKOS vocabularies.
ACTION: Sean to write a proposal to indicate to OWL WG our requirements for annotation properties [recorded in] [CONTINUES]
ACTION: Clay will respond to Jakob about the resolution for notations and x-notation [recorded in] [DONE]
ACTION: Editors of the Use Cases to clean up the lists of requirements in light of resolutions [recorded in] [CONTINUES]
<Ralph> Notations in SKOS [Clay 2008-05-27]
ACTION: Margherita to liase with author primer about example using plain literals and some with datatype literals [recorded in] [CONTINUES]
Alistair: we had some examples of
chemical symbols
... how do you represent this if we include SKOS notation
... we need to see more examples and work them through
<Ralph> RE: Issue-76: SymbolicLabels [Margherita 2008-05-26]
<Ralph> Sean: I was expecting a bit more detail than was in Margherita's mail of yesterday
ACTION: Guus to mail his position on issues 72, 73 and 75 to the list [recorded in] [CONTINUES]
Guus: over next few weeks we must
resolve the open issues in the minutes
... Do we have enough material--we left this open at the F2F
<Ralph> issue-76; SymbolicLabels
Guus: we are now talking about whether to drop them
Alistair: The ongoing discussions
are about notation and not symbol labels. We need Margerita's
examples.
... I don't think we can do more there right now
<Ralph> Alistair: Margherita's examples seem no longer to need symbolic lables
Guus: looks like need for symbolic labels will be dropped
TomB: I propose we drop it
<aliman> +1
<Antoine> +1
Guus: Proposed not to carry
forward SKOS: prefSymbol and altSymbol into the new
namespace
... for lack clear requirements
<Ralph> +1
Guus: seconds?
--RESOLVED
<TomB> RESOLVED: not to carry forward skos:prefSymbol and skos:altSymbol into the new namespace for lack of clear requirements
<Ralph> closes issue-76
-- - SubjectIndicators
Alistair: I think this is out of scope
<Ralph> issue-78; SubjectIndicators
PROPOSED: to not carry forward
SKOS subject indicators
... it is out of scope.
Guus: seconds?
<aliman> I second.
RESOLVED: not to carry forward skos:prefSymbol and skos:altSymbol into the new namespace for lack of clear requirements
-- - SKOS-OWL-Patterns
seanb: Question as to how to publish/describe them
<Ralph> [issue-78 closed]
seanb: I don't see this as part of the technical material to be produced.
<aliman> I agree with seanb
Guus: we might see if people want
to write stuff about this in the primer.
... This doesn't affect technical design of SKOS.
sean: This doesn't affect the design of what we're doing
Alistair: we've kept our options open in design of SKOS
seanb: we are not saying this
isn't important issue. It just need not be in the
reference.
... nor in the primer.
PROPOSAL: to close issue 80
Guus: the technical issues of
SKOS/OWL have already been dealt with
... seconds?
<aliman> I second
RESOLVED: to close issue 80 as the technical issues of SKOS/OWL have already been dealt with
[issue-80 closed]
seanb: I'll take an action to keep this going forward
ACTION: seanb to set up wiki for SKOS/OWL patterns [recorded in]
<aliman> For the record, i think a SKOS/OWL usage note would make a great piece of work, and I really hope Alan Rector & Robert Stevens can contribute.
<TomB> RESOLVED: technical issues of SKOS/OWL have already been dealt with
<Ralph> "progress on SKOS Reference"
Alistair: I have written a new section on mapping properties. Also first draft on extending labels.
<Ralph> editors' draft $Revision: 1.5 $ on $Date: 2008/05/28 13:46:13 $
Alistair: These are the major
content pieces of work to produce new editors' draft
... seanb and I felt we could produce a revised draft by next Tues
Guus: I would be in favor of
publishing that draft
... I propose to publish it as it is without formal review
<TomB> +1 to publish without formal review
Guus: How do editors feel about that?
<seanb> Fine with me.
ACTION: Editors to produce a revised working draft for next week on which we can vote [recorded in]
<aliman> master SKOS Reference
benadida: I have updated primer
to include to respond to comments from Ed and Diego.
... Primer at this point will be ready to go to official working draft.
... We're not discussing and about to close last substantive issue on tracker.
... looks like the issue that has been raised is not significant enough to require change in syntax document.
Guus: so we're adead of the agenda.
Ben: the primer is ready to go after I do one more pass over it.
Guus: on June 10 can we make
request for candidate rec?
... The implementation report need not be done by June 10.
Ben: I think June 10 is good goal.
Guus: What we need is a pointer
to the docs and an indication how you handled last call
... you can point to the tracker.
Ralph: I'll have to produce the enumeration for a director decision.
Guus: In Aug, we need implementation report.
Ben: we keep adding new implementations, which has held up faster completion.
<edsu> yahoo++
Ralph: At Semantic Technologies Conference, Yahoo said searchmonkey will support RDFa.
Ben: They parse pages and it all
ends up in RSS with RDFa.
... they will be parsing RDFa in XHTML.
Guus: we could take a decision next week.
Ben: just want to make sure we've closed the issues.
ACTION: Ben to prepare draft implementation report for RDFa (with assistance from Michael) [recorded in] [CONTINUES]
ACTION: Ralph propose resolution to ISSUE-16 "Default behavior" [recorded in] [CONTINUES]
ACTION: Ed to review the new Editor's Draft of the Recipes [recorded in] [DONE]
ACTION: Ralph/Diego to work on Wordnet implementation [of Recipes implementations] [recorded in] [CONTINUES]
<Ralph> Ed's review of Recipes editors' draft
ACTION: Ralph to review the new Editor's Draft of the Recipes [recorded in] [CONTINUES]
Ralph: I will do it this week
Guus: none of the editors are
here
... Hopefully mor progress on this next week.
... Adjourned
<Ralph> Guus: Regrets for next week
<edsu> Ralph: oh, i forgot to ask you about cvs access ...
<edsu> ... re: antoine's email (if you remember it?)
[adjourned]
$Log: 27-swd-minutes.html,v $ Revision 1.5 2008/05/28 13:46:13 swick Cleanup attendee list and some of the action statuses in-line | http://www.w3.org/2008/05/27-swd-minutes.html | crawl-002 | refinedweb | 1,304 | 57.91 |
None
0 Points
Nov 18, 2012 05:55 AM|CraigMalton|LINK
I have two projects. One is a simple login application and other is a hosted WCF Service that connects to a database.
The WCF service has two methods: "Administrator_Login" and "User_Login".
Whenever each of the methods are called, they execute some code respective to the method: Administrator.Login.Execute and User.Login.Execute (I am organising my code into namespaces, Administrator.Login and User.Login being the class names and Execute being the name of the method).
Both operations return a "LoginOut" object that exist within the User.Login class or Administrator.Login class.
My issue is this: Although each operation is organised into namespaces on the WCF service, when I add a service reference from the client application to the service and look at the names of types of objects returned, I am seein "LoginOut and "LoginOut1".
Is there a way to reference the returned the objects in the client application returned by the WCF service by the namespace?
I am currently having to do this:
Dim loginOut As Service.LoginOut = Service.Administrator_Login().Execute()
Dim loginOut As Service.LoginOut1 = Service.User_Login().Execute()
But I would like to be able to do:
Dim loginOut As Service.Administrator.LoginOut = Service.Administrator_Login().Execute()
Dim loginOut As Service.User.LoginOut = Service.User_Login().Execute()<div>Any help would be greatly appreciated.</div>
Member
290 Points
Nov 20, 2012 01:14 AM|oak_silver|LINK
When you add the service reference, it change one of the method name to avoid confusion since they are at the same namespace. If refine LoginOut1 to LoginOut, they will both call the Service.User_Login().Execute().
1 reply
Last post Nov 20, 2012 01:14 AM by oak_silver | https://forums.asp.net/t/1859403.aspx?WCF+namespace+problem | CC-MAIN-2019-18 | refinedweb | 288 | 50.12 |
#include <GA_FloatTupleAdapter.h>
Definition at line 24 of file GA_FloatTupleAdapter.h.
Create a float tuple adapter for a given attribute. The attribute should be a float tuple. This operation will allocate temporary storage for
size results.
Definition at line 30 of file GA_FloatTupleAdapter.h.
Extract to a templated type, which must have value_type of float.
Definition at line 65 of file GA_FloatTupleAdapter.h.
Extract results to a float array. The float array has stride specified by
asize.
Definition at line 50 of file GA_FloatTupleAdapter.h.
Definition at line 45 of file GA_FloatTupleAdapter.h.
Definition at line 46 of file GA_FloatTupleAdapter.h. | http://www.sidefx.com/docs/hdk/class_g_a___float_tuple_adapter.html | CC-MAIN-2018-30 | refinedweb | 101 | 63.56 |
Functional style universal JavaScript router(yes, another one). I wrote this with the intention to practice some functional programming concepts, and to use it in my own isomorphic apps.
I have been experimenting with isomorphic JavaScript for a while now, and so far none of the current routing solutions has quite convinced me. React-Router is nice, but it is coupled to React and it's API is not as simple as I would like to. Other routing solution add history and hash events management, which ,in my opinion, are out of the responsibility of a router. The prior also makes difficult integration with server side routing.
I wanted a simple url/state pattern mapping tool that executes a function and returns results. And here it is.
$ npm install -S monarch-routes
import routes from 'monarch-routes';const routingTable = {"/users": ()=> "This should return a bunch of people...","/users/:id": ({params})=> {DB.getUser(params.id)}}const monarch = routes(routingTable);monarch('/users'); // This should return a bunch of people...
That's it. I don't think it could be simpler.
monarch-routes takes a routing table in the form of a JavaScript object with the keys being the route pattern to match
,and the value being a handler function for that route pattern. It will return a
monarch function which is our new router.
monarch takes a string path or url and returns whatever the matched handler result is. The handler is invoked with a context
object with the url that matched, the params of the pathname, and the query string variables.
The router uses the same path matcher algorithm than ExpressJS, so integrating with any express-ish app is easy.
Clone this repo and run
npm install and after that run the tests
npm test. | https://www.npmjs.com/package/monarch-routes | CC-MAIN-2017-30 | refinedweb | 294 | 72.97 |
I am trying to optimize code for Monte Carlo simulation. Even minute performance differences piles up after 100 million iterations and thus I need to squeeze every nanosecond from math operations!
One area where I thought I could save a lot stems from the fact that I only require precision of 4 significant digits. It therefore seems natural to use float rather than double.
However, some testing suggests that double still performs better! This is unexpected.
Why is it that despite the fact that float is 32 bits and double 64 bits, mathh functions are quicker to perform exp(double) and pow(double, double) than exp(float) and pow(float, float) (or even expf and powf)? Here is some code...
#include <math.h> #include <iostream> #include "Timer.h" int main() { double a = 23.14; float c = 23.14; Timer t; t.tic(); for (int i = 0; i < 10000000; i++) expf(c); cout<<"expf(float) returns " << expf(c)<<" and took "<<t.toc()<< " seconds." << endl; t.tic(); for (int i = 0; i < 10000000; i++) exp(c); cout<<"exp(float) returns " << exp(c)<<" and took "<<t.toc()<< " seconds." << endl; t.tic(); for (int i = 0; i < 10000000; i++) exp(a); cout<<"exp(double) returns " << exp(a)<<" and took "<<t.toc()<< " seconds." << endl; } | https://www.daniweb.com/programming/software-development/threads/237664/float-and-double-behavior | CC-MAIN-2017-34 | refinedweb | 209 | 76.01 |
Merge lp:compiz-core/gles into lp:compiz-core/0.9.8
This proposal supersedes a proposal from 2012-04-20.
Description of the change_
TODO:
* Port Blur Plugin (Bug 999018)
* Port Cube Plugin (Bug 999017)
- Support vertex clipping (see commented code in glEnableOutputC
- Support proper texture modulation for transparency
- Change GL_QUADS usage in skybox vertex assembly to GL_TRIANGLE usage
* Implement VSync support in EGL codepath: DONE
* Write internal porting guide from GLES to GL
* Push this branch to a testing PPA for Q
* Keep list of regressions up to date and verify with distro
* Write up testing strategy document
Different compiler options most likely, cool that GCC is now catching deleting subclassed objects for which the base has a nonvirtual destructor
@om26er: that compiler error should be fixed ... lets hope there are not other base classes with NVDs lying around ...
thanks, builds fine now. Still figuring how to make it start though ;-)
Code wise, I feel like GLVertexBuffer's begin () and end () API's are a tad clunky, and exist really because GLVertexBuffer:
WARNING:
The diff Launchpad is showing here is completely wrong. It's showing some identical files as changed and failing to show others that are very different (e.g. the water plugin).
I recommend diff'ing the branches manually to get a more realistic idea.
Please look at this proposal instead:
https:/
Unmerged revisions
- 3150. By Daniel van Vugt on 2012-05-16
Fixed water lighting calculations (LP: #1000097)
- Normals were inside-out as I predicted.
- Slightly simplified the shader code.
- Use all 3 dimensions of the lighting vector, not just 2.
- Increased the offset scale (diffraction effect) to look like the old code.
- Reversed lighting vector X component to look like the old code..
- Set lighting vector Z component to zero to avoid lighting whole screen.
- 3149. By Daniel van Vugt on 2012-05-16
Fix annotate turning display completely black (LP: #1000093)
- 3148. By Daniel van Vugt on 2012-05-15
plugins/
opengl/ src/screen. cpp: Delete an outdated comment and deduplicate
another.
- 3147. By Daniel van Vugt on 2012-05-15
Rebase on lp:compiz-core r3137
- 3146. By Sam Spilsbury on 2012-05-14
Give AutoProgram a virtual destructor and move it into a namespace.
Nested classes and nonvirtual destructors on abstract classes are evil.
- 3145. By Sam Spilsbury on 2012-05-14
Start implementing eglSwapBuffers in the paint dispatch. Removed a useless functor check
- 3144. By Sam Spilsbury on 2012-05-14
Remove useless spew
- 3143. By Sam Spilsbury on 2012-05-14
GL_TEXTURE_
COORD_ARRAY client state setting is not necessary because its done implicitly
when binding OpenGL buffer objects.
Disable output clipping, skybox and texture modulation on GLES2 for now
- 3142. By Sam Spilsbury on 2012-05-14
Clip planes aren't yet supported on GLES .. remove glNormal* usage
- 3141. By Sam Spilsbury on 2012-05-14
Port the bottom cap renderer to GLES.
Since both caps use the same vertex array with GL_TRIANGLE_FAN ... a rather unsatisfactory
workaround was added to GLVertexBuffer to control the behaviour of glDrawArrays ... worth looking
into removing
Apart from a few (mostly simple) merge conflicts this builds with trunk. Unsurprisingly the unit tests pass (they don't touch the affected codepath).
Apart from a lack of the usual plugins the result runs. | https://code.launchpad.net/~compiz-linaro-team/compiz-core/compiz-core.gles2/+merge/105616 | CC-MAIN-2019-47 | refinedweb | 547 | 65.22 |
PHP Cookbook/Forms - Revision history 2014-04-16T10:28:42Z Revision history for this page on the wiki MediaWiki 1.11.0 Docbook2Wiki: Initial conversion from Docbook 2008-03-07T13:36:04 13:36, 7 March 2008</td> </tr> </table> Docbook2Wiki Evanlenz: 1 revision(s) 2008-03-06T22:30:05Z <p>1 revision(s)< /> The genius of PHP is its seamless integration of form variables into your programs. It makes web programming smooth and simple, from web form to PHP code to HTML output.<br /> <br /> There's no built-in mechanism in HTTP to allow you to save information from one page so you can access it in other pages. That's because HTTP is a stateless protocol. [[PHP Cookbook/Forms#Processing Form Input|Recipe 9.2]], [[PHP Cookbook/Forms#Working with Multipage Forms|Recipe 9.4]], [[PHP Cookbook/Forms#Redisplaying Forms with Preserved Information and Error Messages|Recipe 9.5]], and [[PHP Cookbook/Forms#Guarding Against Multiple Submission of the Same Form|Recipe 9.6]] all show ways to work around the fundamental problem of figuring out which user is making which requests to your web server.<br /> <br /> [[PHP Cookbook/Forms#Validating Form Input|Recipe 9.3]], to escaping HTML entities to allow the safe display of user entered data, as covered in [[PHP Cookbook/Forms#Escaping Control Characters from User Data|Recipe 9.9]]. Furthermore, [[PHP Cookbook/Forms#Securing PHP's Form Processing|Recipe 9.8]] tells how to protect the security of your web server, and [[PHP Cookbook/Forms#Processing Uploaded Files|Recipe 9.7]] covers how to process files uploaded by a user.<br /> <br /> Whenever PHP processes a page, it checks for GET and POST form variables, uploaded files, applicable cookies, and web server and environment variables. These are then directly accessible in the following arrays: <tt>$_GET</tt> , <tt>$_POST</tt>, <tt>$_FILES</tt>, <tt>$_COOKIE</tt>, <tt>$_SERVER</tt>, and <tt>$_ENV</tt>. They hold, respectively, all variables set by GET requests, POST requests, uploaded files, cookies, the web server, and the environment. There's also <tt>$_REQUEST</tt> , which is one giant array that contains the values from the other six arrays.<br /> <br /> When placing elements inside of <tt>$_REQUEST</tt>, if two arrays both have a key with the same name, PHP falls back upon the <tt>variables_order</tt> configuration directive. By default, <tt>variables_order</tt> is <tt>EGPCS</tt> (or <tt>GPCS</tt>, if you're using the ''php.ini-recommended'' configuration file). So, PHP first adds environment variables to <tt>$_REQUEST</tt> and then adds GET, POST, cookie, and web server variables to the array, in this order. For instance, since <tt>C</tt> comes after <tt>P</tt> in the default order, a cookie named <tt>username</tt> overwrites a POST variable named <tt>username</tt>.<br /> <br /> If you don't have access to PHP's configuration files, you can use <tt>ini_get( )</tt> to check a setting:<br /> <br /> print ini_get('variables_order');<br /> '''EGPCS'''<br /> <br /> <br /> You may need to do this because your ISP doesn't let you view configuration settings or because your script may run on someone else's server. You can also use <tt>phpinfo( )</tt> to view settings. However, if you can't rely on the value of <tt>variables_order</tt>, you should directly access <tt>$_GET</tt> and <tt>$_POST</tt> instead of using <tt>$_REQUEST</tt>.<br /> <br /> The arrays containing external variables, such as <tt>$_REQUEST</tt>, are superglobals. As such, they don't need to be declared as <tt>global</tt> inside of a function or class. It also means you probably shouldn't assign anything to these variables, or you'll overwrite the data stored in them.<br /> <br /> Prior to PHP 4.1, these superglobal variables didn't exist. Instead there were regular arrays named <tt>$HTTP_COOKIE_VARS</tt>, <tt>$HTTP_ENV_VARS</tt>, <tt>$HTTP_GET_VARS</tt>, <tt>$HTTP_POST_VARS</tt>, <tt>$HTTP_POST_FILES</tt>, and <tt>$HTTP_SERVER_VARS</tt>. These arrays are still available for legacy reasons, but the newer arrays are easier to work with. These older arrays are populated only if the <tt>track_vars</tt> configuration directive is <tt>on</tt>, but, as of PHP 4.0.3, this feature is always enabled.<br /> <br /> Finally, if the <tt>register_globals</tt> configuration directive is <tt>on</tt>, all these variables are also available as variables in the global namespace. So, <tt>$_GET['password']</tt> is also just <tt>$password</tt>. While convenient, this introduces major security problems because malicious users can easily set variables from the outside and overwrite trusted internal variables. Starting with PHP 4.2, <tt>register_globals</tt> defaults to <tt>off</tt>.<br /> <br /> With this knowledge, here is a basic script to put things together. The form asks the user to enter his first name, then replies with a welcome message. The HTML for the form looks like this:<br /> <br /> <form action="/hello.php" method="post"><br /> What is your first name?<br /> <input type="text" name="first_name"><br /> <input type="submit" value="Say Hello"><br /> </form><br /> <br /> The <tt>name</tt> of the text <tt>input</tt> element inside the form is <tt>first_name</tt>. Also, the <tt>method</tt> of the form is <tt>post</tt>. This means that when the form is submitted, <tt>$_POST['first_name']</tt> will hold whatever string the user typed in. (It could also be empty, of course, if he didn't type anything.)<br /> <br />:<br /> <br /> echo 'Hello ' . $_POST['first_name'] . '!';<br /> <br /> If the user's first name is Joe, PHP prints out:<br /> <br /> Hello Joe!<br /> <br /> == Processing Form Input ==<br /> <br /> === Problem ===<br /> <br /> You want to use the same HTML page to emit a form and then process the data entered into it. In other words, you're trying to avoid a proliferation of pages that each handle different steps in a transaction.<br /> <br /> === Solution ===<br /> <br /> Use a hidden field in the form to tell your program that it's supposed to be processing the form. In this case, the hidden field is named <tt>stage</tt> and has a value of <tt>process</tt>:<br /> <br /> if (isset($_POST['stage']) && ('process' == $_POST['stage'])) {<br /> process_form();<br /> } else {<br /> print_form();<br /> }<br /> <br /> === Discussion ===<br /> <br />.<br /> <br /> Forms are easier to maintain when all parts live in the same file and context dictates which sections to display. Use a hidden form field named <tt>stage</tt>.<br /> <br /> When writing the HTML for your form, however, don't hardcode the path to your page directly into the <tt>action</tt>. This makes it impossible to rename or relocate your page without also editing it. Instead, PHP supplies a helpful variable:<br /> <br /> $_SERVER['PHP_SELF'] <br /> <br /> This variable is an alias to the URL of the current page. So, set the value of the <tt>action</tt> attribute to that value, and your form always resubmits, even if you've moved the file to a new place on the server.<br /> <br /> So, the example in the introduction of this chapter is now:<br /> <br /> if (isset($_POST['stage']) && ('process' == $_POST['stage'])) {<br /> process_form();<br /> } else {<br /> print_form();<br /> }<br /> <br /> function print_form() {<br /> echo <<<END<br /> <form action="$_SERVER[PHP_SELF]" method="post"><br /> What is your first name?<br /> <input type="text" name="first_name"><br /> <input type="hidden" name="stage" value="process"><br /> <input type="submit" value="Say Hello"><br /> </form><br /> END;<br /> }<br /> <br /> function process_form() {<br /> echo 'Hello ' . $_POST['first_name'] . '!';<br /> }<br /> <br /> If your form has more than one step, just set <tt>stage</tt> to a new value for each step.<br /> <br /> === See Also ===<br /> <br /> [[PHP Cookbook/Forms#Working with Multipage Forms|Recipe 9.4]] for handling multipage forms.<br /> <br /> == Validating Form Input ==<br /> <br /> === Problem ===<br /> <br /> You want to ensure data entered from a form passes certain criteria.<br /> <br /> === Solution ===<br /> <br /> Create a function that takes a string to validate and returns <tt>true</tt> if the string passes a check and <tt>false</tt> if it doesn't. Inside the function, use regular expressions and comparisons to check the data. For example, [[PHP Cookbook/Forms#phpckbk-CHP-9-EX-1|Example 9-1]] shows the <tt>pc_validate_zipcode( )</tt> function, which validates a U.S. Zip Code.<br /> <br /> <div id="phpckbk-CHP-9-EX-1"><br /> '''Example 9-1. pc_validate_zipcode( )'''<br /> <br /> function pc_validate_zipcode($zipcode) {<br /> return preg_match('/^[0-9]{5}([- ]?[0-9]{4})?$/', $zipcode);<br /> }<br /> </div><br /> <br /> Here's how to use it:<br /> <br /> if (pc_validate_zipcode($_REQUEST['zipcode'])) {<br /> // U.S. Zip Code is okay, can proceed<br /> process_data();<br /> } else {<br /> // this is not an okay Zip Code, print an error message<br /> print "Your ZIP Code is should be 5 digits (or 9 digits, if you're ";<br /> print "using ZIP+4).";<br /> print_form();<br /> }<br /> <br /> === Discussion ===<br /> <br /> Deciding what constitutes valid and invalid data is almost more of a philosophical task than a straightforward matter of following a series of fixed steps. In many cases, what may be perfectly fine in one situation won't be correct in another.<br /> <br /> The easiest check is making sure the field isn't blank. The <tt>empty( )</tt> function best handles this problem.<br /> <br /> Next come relatively easy checks, such as the case of a U.S. Zip Code. Usually, a regular expression or two can solve these problems. For example:<br /> <br /> /^[0-9]{5}([- ]?[0-9]{4})?$/ <br /> <br /> finds all valid U.S. Zip Codes.<br /> <br /> Sometimes, however, coming up with the correct regular expression is difficult. If you want to verify that someone has entered only two names, such as "Alfred Aho," you can check against:<br /> <br /> /^[A-Za-z]+ +[A-Za-z]+$/<br /> <br /> However, Tim O'Reilly can't pass this test. An alternative is <tt>/^\S+\s+\S+$/</tt>; but then Donald E. Knuth is rejected. So think carefully about the entire range of valid input before writing your regular expression.<br /> <br /> In some instances, even with regular expressions, it becomes difficult to check if the field is legal. One particularly popular and tricky task is validating an email address, as discussed in [[PHP Cookbook/Regular Expressions#Finding All Lines in a File That Match a Pattern|Recipe 13.7]]. Another is how to make sure a user has correctly entered the name of her U.S. state. You can check against a listing of names, but what if she enters her postal service abbreviation? Will MA instead of Massachusetts work? What about Mass.?<br /> <br /> One way to avoid this issue is to present the user with a dropdown list of pregenerated choices. Using a <tt>select</tt>?<br /> <br />.<br /> <br /> — <tt>AD78DQ</tt> —.<br /> <br />.<br /> <br />.<br /> <br /> === See Also ===<br /> <br /> [[PHP Cookbook/Regular Expressions#Finding All Lines in a File That Match a Pattern|Recipe 13.7]] for a regular expression for validating email addresses; [[PHP Cookbook/Classes and Objects|Chapter 7]], "Validation on the Server and Client," of ''Web Database Applications with PHP and MySQL'' (Hugh Williams and David Lane, O'Reilly).<br /> <br /> == Working with Multipage Forms ==<br /> <br /> === Problem ===<br /> <br /> You want to use a form that displays more than one page and preserve data from one page to the next.<br /> <br /> === Solution ===<br /> <br /> Use session tracking:<br /> <br /> session_start();<br /> $_SESSION['username'] = $_GET['username'];<br /> <br /> You can also include variables from a form's earlier pages as hidden input fields in its later pages:<br /> <br /> <input type="hidden" name="username" <br /><br /> <br /> === Discussion ===<br /> <br /> Whenever possible, use session tracking. It's more secure because users can't modify session variables. To begin a session, call <tt>session_start( )</tt>; this creates a new session or resumes an existing one. Note that this step is unnecessary if you've enabled <tt>session.auto_start</tt> in your ''php.ini'' file. Variables assigned to <tt>$_SESSION</tt> are automatically propagated. In the Solution example, the form's username variable is preserved by assigning <tt>$_GET['username']</tt> to <tt>$_SESSION['username']</tt>.<br /> <br /> To access this value on a subsequent request, call <tt>session_start( )</tt> and then check <tt>$_SESSION['username']</tt>:<br /> <br /> session_start( );<br /> $username = htmlentities($_SESSION['username']);<br /> print "Hello $username.";<br /> <br /> In this case, if you don't call <tt>session_start( )</tt>, <tt>$_SESSION</tt> isn't set.<br /> <br /> Be sure to secure the server and location where your session files are located (the filesystem, database, etc.); otherwise your system will be vulnerable to identity spoofing.<br /> <br />.<br /> <br /> The most basic way to use hidden fields is to include them inside your form.<br /> <br /> <form action="<?php echo $_SERVER['PHP_SELF']; ?>"<br /><br /> <br /> <input type="hidden" name="username" <br /><br /> <br /> When this form is resubmitted, <tt>$_GET['username']</tt> holds its previous value unless someone has modified it.<br /> <br /> A more complex but secure solution is to convert your variables to a string using <tt>serialize( )</tt> , compute a secret hash of the data, and place both pieces of information in the form. Then, on the next request, validate the data and unserialize it. If it fails the validation test, you'll know someone has tried to modify the information.<br /> <br /> The <tt>pc_encode( )</tt> encoding function shown in [[PHP Cookbook/Forms#phpckbk-CHP-9-EX-2|Example 9-2]] takes the data to encode in the form of an array.<br /> <br /> <div id="phpckbk-CHP-9-EX-2"><br /> '''Example 9-2. pc_encode( )'''<br /> <br /> $Stew's favorite movie.</a>\n";<br /> print htmlspecialchars($html); // double-quotes<br /> print htmlspecialchars($html, ENT_QUOTES); // single- and double-quotes<br /> print htmlspecialchars($html, ENT_NOQUOTES); // neither<br /> '''&lt;a href=&quot;fletch.html&quot;&gt;Stew's favorite movie.&lt;/a&gt;'''<br /> '''&lt;a href=&quot;fletch.html&quot;&gt;Stew&#039;s favorite movie.&lt;/a&gt;'''<br /> '''&lt;a<br /> <br /> When a user clicks on the image, the x and y coordinates are submitted as <tt>locations.x</tt> and <tt>locations.y</tt>. So, in PHP, to find where a user clicked, you need to check <tt>$_REQUEST['locations_x']</tt> and <tt>$_REQUEST['locations_y']</tt>.<br /> <br /> It's possible, through a series of manipulations, to create a variable inside PHP with a period:<br /> <br /> ${"a.b"} = 123; // forced coercion using {}<br /> <br /> $ The Bronx<br /> <input type="checkbox" name="boroughs[]" value="brooklyn"> Brooklyn<br /> <input type="checkbox" name="boroughs[]" value="manhattan"> Manhattan<br /> <input type="checkbox" name="boroughs[]" value="queens"> Queens<br /> <input type="checkbox" name="boroughs[]" value="statenisland"> Staten Island<br /> <br /> Inside your program, treat the variable as an array:<br /> <br /> print 'I love ' . join(' and ', $boroughs) . '!';<br /> <br /> === Discussion ===<br /> <br /> By placing <tt>[ ]</tt>:<br /> <br /> $boroughs[ ] = "bronx";<br /> $boroughs[ ] = "brooklyn";<br /> $boroughs[ ] = "manhattan";<br /> <br /> You can use this to return information from a database that matches multiple records:<br /> <br /> foreach ($_GET['boroughs'] as $b) {<br /> $boroughs[ ] = strtr($dbh->quote($b),array('_' => '\_', '%' => '\%'));<br /> }<br /> $locations = join(',', $boroughs);<br /> <br /> $dbh->query("SELECT address FROM locations WHERE borough IN ($locations)");<br /> <br /> This syntax also works with multidimensional arrays:<br /> <br /> <input type="checkbox" name="population[NY][NYC]" value="8008278">New York...<br /> <br /> If checked, this form element sets <tt>$population['NY']['NYC']</tt> <tt>to</tt> <tt>8008278</tt>.<br /> <br /> Placing a <tt>[ ]</tt> <tt>[ ]</tt>, and use that ID instead. Given:<br /> <br /> <form><br /> <input type="checkbox" name="myName[]" value="myValue" id="myName"><br /> </form><br /> <br /> the following three refer to the same form element:<br /> <br /> document.forms[0].elements[0]; // using numerical IDs<br /> document.forms[0].elements['myName[ ]']; // using the name with quotes<br /> document.forms[0].elements['myName']; // using ID you assigned<br /> <br /> === See Also ===<br /> <br /> The introduction to [[PHP Cookbook/Arrays|Chapter 4]] for more on arrays.<br /> <br /> == Creating Dropdown Menus Based on the Current Date ==<br /> <br /> === Problem ===<br /> <br /> You want to create a series of dropdown menus that are based automatically on the current date.<br /> <br /> === Solution ===<br /> <br /> Use <tt>date( )</tt> to find the current time in the web server's time zone and loop through the days with <tt>mktime( )</tt>.<br /> <br /> The following code generates <tt>option</tt> values for today and the six days that follow. In this case, "today" is January 1, 2002.<br /> <br /> list($hour, $minute, $second, $month, $day, $year) = <br /> split(':', date('h:i:s:m:d:Y'));<br /> <br /> // print out one week's worth of days<br /> for ($i = 0; $i < 7; ++$i) {<br /> $timestamp = mktime($hour, $minute, $second, $month, $day + $i, $year); <br /> $date = date("D, F j, Y", $timestamp);<br /> <br /> print "<option value=\"$timestamp\">$date</option>\n";<br /> }<br /> '''<option value="946746000">Tue, January 1, 2002</option>'''<br /> '''<option value="946832400">Wed, January 2, 2002</option>'''<br /> '''<option value="946918800">Thu, January 3, 2002</option>'''<br /> '''<option value="947005200">Fri, January 4, 2002</option>'''<br /> '''<option value="947091600">Sat, January 5, 2002</option>'''<br /> '''<option value="947178000">Sun, January 6, 2002</option>'''<br /> '''<option value="947264400">Mon, January 7, 2002</option>'''<br /> <br /> <br /> === Discussion ===<br /> <br /> In the Solution, we set the <tt>value</tt> for each date as its Unix timestamp representation because we find this easier to handle inside our programs. Of course, you can use any format you find most useful and appropriate.<br /> <br /> Don't be tempted to eliminate the calls to <tt>mktime( )</tt>; dates and times aren't as consistent as you'd hope. Depending on what you're doing, you might not get the results you want. For example:<br /> <br /> $timestamp = mktime(0, 0, 0, 10, 24, 2002); // October 24, 2002<br /> $one_day = 60 * 60 * 24; // number of seconds in a day<br /> <br /> // print out one week's worth of days<br /> for ($i = 0; $i < 7; ++$i) {<br /> $date = date("D, F j, Y", $timestamp);<br /> <br /> print "<option value=\"$timestamp\">$date</option>";<br /> <br /> $timestamp += $one_day;<br /> }<br /> '''<option value="972619200">Fri, October 25, 2002</option>'''<br /> '''<option value="972705600">Sat, October 26, 2002</option>'''<br /> '''<option value="972792000">Sun, October 27, 2002</option>'''<br /> '''<option value="972878400">Sun, October 27, 2002</option>'''<br /> '''<option value="972964800">Mon, October 28, 2002</option>'''<br /> '''<option value="973051200">Tue, October 29, 2002</option>'''<br /> '''<option value="973137600">Wed, October 30, 2002</option>'''<br /> <br /> <br /> This script should print out the month, day, and year for a seven-day period starting October 24, 2002. However, it doesn't work as expected.<br /> <br />.<br /> <br /> === See Also ===<br /> <br /> [[PHP Cookbook/Dates and Times|Chapter 3]], particularly [[PHP Cookbook/Dates and Times#Accounting for Daylight Saving Time|Recipe 3.13]], but also [[PHP Cookbook/Dates and Times#Finding the Current Date and Time|Recipe 3.2]], [[PHP Cookbook/Dates and Times#Converting Time and Date Parts to an Epoch Timestamp|Recipe 3.3]], [[PHP Cookbook/Dates and Times#Printing a Date or Time in a Specified Format|Recipe 3.5]], [[PHP Cookbook/Dates and Times#Adding to or Subtracting from a Date|Recipe 3.11]], and [[PHP Cookbook/Dates and Times#Generating a High-Precision Time|Recipe 3.14]]; documentation on <tt>date( )</tt> at '''' and <tt>mktime( )</tt> at ''''.</div> Docbook2Wiki | http://commons.oreilly.com/wiki/index.php?title=PHP_Cookbook/Forms&action=history&feed=atom | CC-MAIN-2014-15 | refinedweb | 3,279 | 54.42 |
Provided by: libncarg-dev_6.3.0-6build1_amd64
NAME
EZSRFC - Draws a perspective picture of a function of two variables with hidden lines removed. The function is approximated by a two-dimensional array of heights. Use EZSRFC only if the entire array is to be drawn, the data points are equally spaced in the X-Y plane, there are no stereo pairs, and scaling is chosen internally.
SYNOPSIS
CALL EZSRFC (Z,M,N,ANGH,ANGV,WORK)
C-BINDING SYNOPSIS
#include <ncarg/ncargC.h> void c_ezsrfc (float *z, int m, int n, float angh, float angv, float *work)
DESCRIPTION
Z The M by N array to be drawn. M The first dimension of Z. N The second dimension of Z. ANGH Angle in degrees in the X-Y plane to the line of sight (counterclockwise from the plus-X axis). ANGV Angle in degrees from the X-Y plane to the line of sight (positive angles are above the middle Z, negative below). WORK A scratch storage dimensioned at least 2*M*N+M+N.
C-BINDING DESCRIPTION
The C-binding argument descriptions are the same as the FORTRAN argument descriptions, with the following exceptions: z The n by m array to be drawn. m The second dimension of z. n The first dimension of z.
EXAMPLES
Use the ncargex command to see the following relevant examples: fsrezsrf, tsrfac.
ACCESS
To use EZSRFC or c_ezsrfc, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
SEE ALSO
Online: surface, surface_params, pwrzs, setr, srface. ncarg_cbind. Hardcopy: NCAR Graphics Fundamentals, UNIX Version
Copyright (C) 1987-2009 University Corporation for Atmospheric Research The use of this Software is governed by a License Agreement. | http://manpages.ubuntu.com/manpages/xenial/man3/ezsrfc.3NCARG.html | CC-MAIN-2019-30 | refinedweb | 281 | 56.96 |
A huge number of text articles are generated everyday from different publishing houses, blogs, media, etc. This leads to one of the major tasks in natural language processing i.e. effectively managing, searching and categorizing articles depending upon their subjects or themes. Typically, these text mining tasks will include text clustering, document similarity and categorization of text. Comprehensively, we have to find out some ways so that the theme of the article can be extracted. In text analytics, this is known as “Topic Modelling”. Also, given a topic, our software should be able to find out articles which are similar to it. This is known as “Document Similarity”.
Deriving such meaningful information from text documents is the main objective of this blog-post series. I will be covering the whole application of topic modelling in 3 blog-posts. The purpose of the blog-post series is to build the system from scratch and provide an insight of implementation of the same to our readers. This particular post will be focusing on creating a corpus of Simple Wikipedia articles from dumped simple wiki XML file. Once the text data (articles) has been retrieved, it can be used by machine learning techniques for model training in order to discover topics from the text corpus.
There are mainly two steps in the text data retrieval process from simple Wikipedia dump:
1. XML parsing of the wiki dump
2. Cleaning of the articles’ text
The Simple Wikipedia is an edition of the online encyclopedia Wikipedia, primarily written in Basic English. The articles on Simple Wikipedia are usually shorter than their English Wikipedia counterparts, presenting only the basic information. It contains over 127,000 content pages for people to search, explore or even edit. We downloaded the free backup XML file in which all the articles are dumped. Then a sample of 60,000 simple Wikipedia articles is randomly selected for building the application. You can download the same backup XML file(used in this blog) from here or it can be downloaded from index of simple wiki website.
1. XML Parsing of Wiki Dump
All the information of an article like title, id, time stamp, contributor, text content, etc lies in the
page tag of XML file. There are more than 100,000 such legitimate pages. A typical article in wiki dumped XML file looks like this.
The Document Object Model (tree view) represents this XML snippet like this:
Seeing all this, one can observe that we have to get article text from the
text tag in the XML file, which is one of the children of the
revision tag (
revision itself being a child of the
page tag). We will use the Element Tree XML API for parsing the XML file and extracting the text portion of the article. The below Python code traverses down the tree to get the content of the
text tag. The contents of each article are extracted from the
text tag of that corresponding page in iterations and can be written in separate text files.
import xml.etree.ElementTree as ET import codecs import re tree = ET.parse('simplewiki-20170201-pages-articles-multistream.xml') root = tree.getroot() path = 'articles-corpus//' url = '{}page' for i,page in enumerate(root.findall(url)): for p in page: r_tag = "{}revision" if p.tag == r_tag: for x in p: tag = "{}text" if x.tag == tag: text = x.text if not text == None: # Extracting the text portion from the article text = text[:text.find("==")] # <em><strong>Cleaning of Text (described in Section 2)</strong></em> # Printing the article print text print '\n====================================\n'
Also, we are only interested in getting the introductory text about the
title (like in above sample, the title is “Treason”), not its subheading or other contents like
Responsibilities to Protect and
References. In order to do this, we extract the sub string from starting index to the index location before the start of the first subheading. It is implemented by the Python statement given below:
text = text[: text.find("==")].
The created text article for the above sample page looks like this:
2. Cleaning of Article Text
Data pre-processing (a.k.a data cleaning) is one of the most significant step in text analytics. The purpose is to remove any unwanted words or characters which are written for human readability, but won’t contribute to topic modelling in any way.
There are mainly two steps that need to be done on word level:
a) Removal of stop words – Stop words like “and”, “if”, “the”, etc are very common in all English sentences and are not very meaningful in deciding the theme of the article, so these words have been removed from the articles.
b) Lemmatization – It is the process of grouping together the different inflected forms of a word so they can be analysed as a single item. For example, “include”, “includes,” and “included” would all be represented as “include”. The context of the sentence is also preserved in lemmatization as opposed to stemming (another buzz word in text mining which does not consider the meaning of the sentence).
The following Python code defines a function
clean() for cleaning the text article passed as an argument to it:
from nltk.corpus import stopwords from nltk.stem.wordnet import WordNetLemmatizer import string stop = set(stopwords.words('english')) exclude = set(string.punctuation) lemma = WordNetLemmatizer() # pass the article text as string "doc" def clean(doc): # remove stop words & punctuation, and lemmatize words s_free = " ".join([i for i in doc.lower().split() if i not in stop]) p_free = ''.join(ch for ch in s_free if ch not in exclude) lemm = " ".join(lemma.lemmatize(word) for word in p_free.split()) words = lemm.split() # only take words which are greater than 2 characters cleaned = [word for word in words if len(word) > 2] return cleaned
We will plug the above cleaning code in the next blog-post where the training code of the Latent Dirichlet Allocation (LDA) model will be shown in order to discover hidden topics from the corpus. As of now, we are focusing only on creating the wiki corpus of articles.
Specially for Wikipedia articles, one needs to apply several steps to clean the article text which includes removal of File attachment, Image attachments, URLs, Infobox, XML labels, etc. The following Python code applies regular expression for matching such patterns and removing them. These 30 filters are applied depending on my analysis of the wiki text. There may be several other patterns which might have been missed here.
# remove text written between double curly braces article_txt = re.sub(r"{{.*}}","",article_txt) # remove file attachments article_txt = re.sub(r"\[\[File:.*\]\]","",article_txt) # remove Image attachments article_txt = re.sub(r"\[\[Image:.*\]\]","",article_txt) # remove unwanted lines starting from special characters article_txt = re.sub(r"\n: \'\'.*","",article_txt) article_txt = re.sub(r"\n!.*","",article_txt) article_txt = re.sub(r"^:\'\'.*","",article_txt) # remove non-breaking space symbols article_txt = re.sub(r" ","",article_txt) # remove URLs link article_txt = re.sub(r"http\S+","",article_txt) # remove digits from text article_txt = re.sub(r"\d+","",article_txt) # remove text written between small braces article_txt = re.sub(r"\(.*\)","",article_txt) # remove sentence which tells category of article article_txt = re.sub(r"Category:.*","",article_txt) # remove the sentences inside infobox or taxobox article_txt = re.sub(r"\| .*","",article_txt) article_txt = re.sub(r"\n\|.*","",article_txt) article_txt = re.sub(r"\n \|.*","",article_txt) article_txt = re.sub(r".* \|\n","",article_txt) article_txt = re.sub(r".*\|\n","",article_txt) # remove infobox or taxobox article_txt = re.sub(r"{{Infobox.*","",article_txt) article_txt = re.sub(r"{{infobox.*","",article_txt) article_txt = re.sub(r"{{taxobox.*","",article_txt) article_txt = re.sub(r"{{Taxobox.*","",article_txt) article_txt = re.sub(r"{{ Infobox.*","",article_txt) article_txt = re.sub(r"{{ infobox.*","",article_txt) article_txt = re.sub(r"{{ taxobox.*","",article_txt) article_txt = re.sub(r"{{ Taxobox.*","",article_txt) # remove lines starting from * article_txt = re.sub(r"\* .*","",article_txt) # remove text written between angle bracket article_txt = re.sub(r"","",article_txt) # remove new line character article_txt = re.sub(r"\n","",article_txt) # replace all punctuations with space article_txt = re.sub(r"\!|\"|\#|\$|\%|\&|\'|\(|\)|\*|\+|\,|\-|\.|\/|\:|\;|\|\?|\@|\[|\\|\]|\^|\_|\`|\{|\||\}|\~"," ",article_txt) # replace consecutive multiple space with single space article_txt = re.sub(r" +"," ",article_txt) # replace non-breaking space with regular space article_txt = article_txt.replace(u'\xa0', u' ') # Writing the clean text in file if len(article_txt) > 150 and is_ascii(article_txt) and not article_txt == None and not article_txt == "": outfile = path + str(i+1) +"_article.txt" f = codecs.open(outfile, "w", "utf-8") f.write(article_txt) f.close()
The above code snippet of text filters can be plugged to the text extracted from the
text tag (Figure 1). Finally, we keep only those articles which have length more than 150 characters. Also, we check and write only those text articles which contain only ASCII characters (English characters only).
This completes the first step towards Topic modeling, i.e. creating the corpus of articles from simple Wikipedia. Once you follow this blog till here, you will be able to create a corpus of around 70,000 articles in the directory “articles-corpus” used in python program. I will be writing about discovering the hidden topics from the corpus created in the next blog-post soon. So stay tuned till then !!
You can get the full Python code for parsing, cleaning and creating an article corpus (from simple wiki XML dump file) from GitHub link here. machine learning 🙂
Thankyou for the article great help .
LikeLiked by 1 person
Glad you liked.
THANK YOU FOR THE DETAIL INFO…CAN YOU HELP ME IN OBTAINING BIOMEDICAL ARTICLES FROM PUBMED
Hi Abhijeet, Sorry to disturb you again.
I tried to extract the whole wikipedia dump, which is around 63GB(after extracting) but my system could not take the load. After changing my system configurations (Ram:16GB, 120GBSSD hard disk, Processor i5), still can’t run my program . It’s giving MemoryError.
Please help me.
Hi Astha,
Are you using simple wikipedia dump or wikipedia dump ?
Seems like you are taking wikipedia dump.
Is this a single xml file of 63 GB ?
Can you elaborate your situation ?
Hope I’m able to explain myself well
enwiki-latest-pages-articles.xml.bz2(14.4 GB)(It’s a wikipedia dump)
After unzipping it’s size is 64.7 GB.
So when I exract it by your code it throws memory error.
Please suggest something that works for the above wikipedia dump.
Thanks.
Oh it’s huge.
So basically you may need to use some package which can read/parse it serially. That means it should load only a part of file in RAM at a time.
There would be ways for that. Like this
But if you are doing it for first time, you can go for simple Wikipedia dump oops which will be small.
Hi Abhijeet, Thanks for replying
I tried on Simple Wikipedia Dump & it worked fine. So, I wanted to try on Large wikipedia dump. I followed that link & tried to extract, it’s been more than 24 hours & it’s still running.
Please tell if it will take this much time
LikeLiked by 1 person
Hi,
Firstly,
I do not know what’s the tree structure of Large wiki dump. The XML parser written in this post is for simple wiki. It may not work.
Secondly,
If at all it is working fine then you would be able to see it in the directory where the program would write text articles in separate files.
If it is running actually from 24 hours it would have generated lakhs of files. | https://appliedmachinelearning.blog/2017/08/28/topic-modelling-part-1-creating-article-corpus-from-simple-wikipedia-dump/ | CC-MAIN-2021-25 | refinedweb | 1,894 | 58.38 |
Wait a minute, we could place our finished Simple Paste Applet, as seen on this page, onto this SVG background. Click this sentence to see the what the codebase of it would look like. (Refers to an empty page as I don't have a clue how to import and set an SVG)
Hey don't stray, we have much to learn about SVG. The idea for our plasmoid is as follows: once created we repeat the following steps:
We don't use any bitmap buffering unless required to do so, this way we can see if tracing simple SVG elements has any impact on the CPU. The widget in the C++ Weather Station plasmoid was custom created in the KDE 4.0 days, I don't know why (perhaps to optimize bitmap buffering) nor do I know if plasma has further improved SVG support since 4.0. I just picked the Weather Station plasmoid because if has a nice, clean and clear named SVG (notice that the Weather Station has two interfaces and two SVGs, one huge and complex one and the minimized one used here).
After a more experienced Ruby programmer has expanded the code to include the SVG and to make the three zero digits blink on for half a second and then off for half a second, like an unset alarm clock, the code looks like this:
require 'plasma_applet'
module Blinker
class Main < PlasmaScripting::Applet def initialize parent super parent end
def init set_minimum_size 128, 128 end def init @svg = Plasma::Svg.new(self) @svg.imagePath = package.filePath("images", "lcd_panel.svgz") end
def paintInterface(painter, option, contentsRect) @svg.resize(size()) # @svg.set_svg = package.filePath("images/lcd_panel.svgz", "temperature:1") @svg.paint(painter, 0, 0) end end
end. | https://techbase.kde.org/index.php?title=Development/Tutorials/Plasma/Ruby/Blinker&diff=49426&oldid=49183 | CC-MAIN-2015-32 | refinedweb | 291 | 63.83 |
In Multimedia fusion 1.5 and highest is very good extension- 'Screen capture object' (it is making screenshot of our screen). Is in Construct something like this??? I really need it!!!
AltGr + Print screen grabs the current window. Cropping the game area shouldn't be too much of a hassle after that. I don't know whether there's a screen grabbing plugin as I've never needed one myself.
I would like the game to automatically make a montage of the game run thru. Because it cannot grab the screen, it would seem this cannot be done currently in Construct, correct? I can see it being done easily with a canvas & imageManipulator, but that's a big canvas for something so trivial. Python can do this correct?
I would like to do screenshot without using Alt+PrintScreen. And, I want all screen area (desktop, icons) in my screenshot, no only application window! In multimedia fusion is special extension - Capture Screen object... How about Construct?
Yes, you can do this with Python.
Thanx man! But... must I install this all libraries, python language and more different programs on another computers where I want to launch my application, for example on my friend computer?
But... must I install this all libraries, python language and more different programs on another computers
But... must I install this all libraries, python language and more different programs on another computers
No, you don't have to install anything on your friends computer. If you read through the tut you will see that you run it just like any other Construct program. You just have to do a little more work to package things up. Here is a quick example of two screenshots tools I put together: One takes a screenshot of the desktop as soon as it is run, the other takes it when you click the button in the gui.
I try to run your example on my friend computer, and it's doesn't work . First, python26.dll is needed, so I copy this to your example directory. Next, I try to run it again and... (0xc0150002) error. Any sugestions? Thank you very much!
Develop games in your browser. Powerful, performant & highly capable.
oops, I forgot to include the Python26.dll. I have uploaded a new version with the Dll. Try this one out:
I tried this on a clean XP Sp2 system, just built with no Python installed and everything worked good. Also tried it on a system with Python installed and it worked. However, there have been a few rare cases where people couldn't get them to work.
If it still has an error, could you run the Microsoft vcredist executable I now have in the directory? If that still fails to solve it please tell me what the full exact error message is? Also, what operating system is your friend using (XP, vista, 7?) and what service pack?
EDit: Just uploaded new version so redownload the one with the vcredist executable in it.
Thx, but it's still not working without Python installed on the machine... When I try to run your application, I see a error-window:
"The application failed to initialize properly (0xc0150002). Click on OK to terminate the application".
I installed PYTHON 2.6 and all libraries from article "python_library_tutorial_part2.pdf" and it's working good... But I want this working without Python installed on computer. Thanks!
EDIT:
OK, I'm waiting for your new upload. If it will work good without installed python, can you write simple, short article for me, how to do this (I have example in *.cap, but when I create EXE file, it's not working). Thank you very much!!!
See!
I downloaded your new package and uninstalled Python 2.6 from my WindowsXP. IT'S WORKING CORRECTLY! Thank you, man!!!
Now, I want to create my own application in Construct. I'm reading an article "python_library_tutorial_part2", I installed all nessesary programs - Python 2.6, GTK+ All In One, PyCairo, PyGObject and cx_Freeze... But... I don't understand this:
"Go ahead and build an executable using cx_freeze. Now copy the library.zip file that was
produced and paste it into the Construct/Data/Python directory. Finally, unzip this file into the
directory."
I don't know how to build an executable using cx_freeze and how to get "library.zip".
Uh... isn't using python library solely for taking screenshots a bit excessive?
Sounds like you are close to getting the build to work. Here are the steps from where you are at.
1. On page 3 of the Part 2 tutorial there is a Python script. You need to create a file called "test.py" and copy the import lines of the script into that file. Read the Python_quickguide if you have not already.
The file should have the imports:
import sys
import pygtk
import gtk
2. Once you have the script, you need to build a cx_freeze build script called "setup.py" like below in the same directory as the script you just created. This is shown in the Python_quickguide.
from cx_Freeze import setup, Executable
setup(
name = "screenshot",
version = "0.1",
description = "Basic screenshot example",
executables = [Executable("test.py")])
3. Once you have done that, open up a command prompt, cd to your directory and run the tool:
"setup.py build"
4. This step produces the library.zip file and all of the other dependencies that you see I copied with the executable. You unzip the library.zip file into your Construct\Data\Python directory. The other dependencies you bundle with your executable. You might also have to bundle the vcredistributable as I was explaining earlier.
Give the quickguide a short review and hopefully this all works!
Uh... isn't using python library solely for taking screenshots a bit excessive?
Of course it is. but how else would you have him accomplish this? Write his own plugin in C++?? | https://www.construct.net/en/forum/construct-classic/help-support-using-construct-classic-38/screenshot-using-construct-35976 | CC-MAIN-2018-43 | refinedweb | 989 | 77.33 |
exit(2) exit(2)
exit, _exit - terminate process
#include <stdlib.h>
void exit(int status);
#include <unistd.h>
void _exit(int status);
The C library routine exit, which is discussed at the end of this
section, invokes the system routine _exit upon completion of its own
cleanup chores. _exit terminates the calling process with the following
consequences:
All of the file descriptors, directory streams and message catalogue
descriptors open in the calling process are closed. If the process
is sharing file descriptors via an sproc, other members of the share
group do NOT have their file descriptors closed.
A SIGCHLD signal is sent to the calling process's parent process.
If the parent process of the calling process has not specified the
SA_NOCLDWAIT flag [see sigaction(2)], the calling process is
transformed into a ``zombie process.'' A zombie process is a
process that only occupies a slot in the process table. It has no
other space allocated either in user or kernel space. The process
table slot that it occupies is partially overlaid with time
accounting information [see <sys/proc.h>] to be used by the times
system call.
The parent process ID of all of the calling process's existing child
processes and zombie processes is set to 1. This means the
initialization process [see intro(2)] inherits each of these
processes.
If the process belongs to a share group, it is removed from that
group. Its stack segment is deallocated and removed from the share
group's virtual space. All other virtual space that was shared with
the share group is left untouched. If the prctl (PR_SETEXITSIG)
option has been enabled for the share group, than the specified
signal is sent to all remaining share group members.
Each attached shared memory segment is detached and the value of
shm_nattach in the data structure associated with its shared memory
identifier is decremented by 1.
Page 1
exit(2) exit(2)
For each semaphore for which the calling process has set a semadj
value [see semop(2)], that semadj value is added to the semval of
the specified semaphore.
If the process has a process, text, or data lock, an unlock is
performed [see plock(2)]. If the process has any pages locked, they
are unlocked [see mpin(2)].
An accounting record is written on the accounting file if the
system's accounting routine is enabled [see acct(2)].
If the process is a controlling process, SIGHUP is sent to the
foreground process group of its controlling terminal and its
controlling terminal is deallocated.
If the calling process has any stopped children whose process group
will be orphaned when the calling process exits, or if the calling
process is a member of a process group that will be orphaned when
the calling process exits, that process group will be sent SIGHUP
and SIGCONT signals. Note that these signals are not sent if the
process became the process group leader through the invocation of
the setpgrp(2) system call.
In all cases, if the calling process is a process group leader and
has an associated controlling terminal, the controlling terminal is
disassociated from the process allowing it to be acquired by another
process group leader.
Any mapped files are closed and any written pages flushed to disk.
The C function exit(3C) calls any functions registered through the atexit
function in the reverse order of their registration. It then causes each
buffered file stream to be flushed, and, unless an sproc has been
executed, closed. The function _exit circumvents all such functions and
cleanup.
The symbols EXIT_SUCCESS and EXIT_FAILURE are defined in stdlib.h and may
be used as the value of status to indicate successful or unsuccessful
termination, respectively.
acct(2), intro(2), plock(2), semop(2), sigaction(2), signal(2), mmap(2),
mpin(2), prctl(2), sigprocmask(2), sigvec(3B), sigblock(3B),
sigsetmask(3B), times(2), wait(2), atexit(3C).
See signal(2) NOTES.
PPPPaaaaggggeeee 2222 | https://nixdoc.net/man-pages/IRIX/man2/exit.2.html | CC-MAIN-2021-10 | refinedweb | 657 | 61.56 |
I recently ran into a problem where my .NET API was returning an error 415. The full error gives you a hint as to what the actual issue is : “415 Unsupported Media Type”, although this can lead you down a wild goose chase of stackoverflow answers.
In short, the API is expecting a post request with a particular content-type header, but the caller (Or maybe your front end) is using a different media type. There are actually some other gotchas that are incredibly frustrating to figure out in .NET too that can blow this entire thing up without you noticing. But let’s get on to it!
Check Your Front End Caller
The first thing we need to do is understand what our API is expecting. In general, API’s these days are expecting JSON requests. In some cases, they are expecting a classic “form post”. These are not the same thing! But whichever you use, your front end caller (Whether that be a javascript library or another machine), must attach the correct content type when making a request to the API.
For example, if I have a JSON API, and I make the following call from jQuery :
$.ajax({
url: ‘/myapiendpoint’,
type: ‘POST’
});
This actually won’t work! Why? Because the default content-type of an Ajax request from jQuery is actually “application/x-www-form-urlencoded”, not “application/json”. This can catch you out if you aren’t familiar with the library and it’s making calls using the default content-type.
But of course, we can go the other way where you copy and paste someone’s helpful code from stackoverflow that forces the content-type to be JSON, but you are actually using form posts :
$.ajax({
url: ‘/myapiendpoint’,
contentType: ‘application/json’
type: ‘POST’
});
Don’t think that you are immune to this just because you are using a more modern library. Every HttpClient library for javascript will have some level of default Content Type (Typically application/json), and some way to override it. Often, libraries such as HttpClient in Angular, or Axios, have ways to globally override the content-type and override it per request, so it can take some time working out exactly how the front end is working.
When it comes down to it, you may need to use things like your browser dev tools to explicitly make sure that your front end library is sending the correct content-type. If it is, and you are certain that the issue doesn’t lie there, then we have to move to debugging the back end.
Checking The Consumes Attribute
If we are sure that our front end is sending data with a content-type we are expecting, then it must be something to do with our backend. The first thing I always check is if we are using the Consumes attribute. They look a bit like this :
[Consumes(“application/xml”)]
public class TestController : ControllerBase
{
}
Now in this example, I’ve placed the attribute on the Controller, but it can also be placed directly on an action, or even added to your application startup to apply globally, so your best bet is usually a “Ctrl + Shift + F” to find all of them.
If you are using this attribute, then make sure it matches what the front end is sending. In 99% of cases, you actually don’t need this attribute except for self documenting purposes, so if you can’t find this in use anywhere, that’s normal. Don’t go adding it if you don’t already have it and are running into this issue, because often that will just complicate matters.
In the above example, I used [Consumes(“application/xml)] as an example of what might break your API and return an error 415. If my front end has a content-type of json, and my consumes specifies I’m expecting XML, then it’s pretty clear there’s going to be a conflict of some kind we need to resolve.
Checking FromBody vs FromForm
Still not working? The next thing to check is if you are using FromBody vs FromForm correctly. Take this action for example :
public IActionResult MyAction([FromForm]object myObject)
This endpoint can only be called with non form post data. e.g. The content type must be “application/x-www-form-urlencoded”. Why? Because we are using the [FromForm] attribute.
Now if we change it to FromBody like so :
public IActionResult MyAction([FromBody]object myObject)
This can only accept “body” types of JSON, XML etc. e.g. Non form encoded content types. It’s really important to understand this difference because sometimes people change the Consumes attribute, without also changing how the content of the POST is read. This has happened numerous times for me, mostly when changing a JSON endpoint to just take form data because a particular library requires it.
ApiController Attribute
Finally, I want to talk about a particular attribute that might break an otherwise working API. In .NET Core and .NET 5+, there is an attribute you can add to any controller (Or globally) called “ApiController”. It adds certain conventions to your API, most notably it will check ModelState for you and return a nice error 400 when the ModelState is not valid.
However, I have seen API’s act very differently when it comes to modelbinding, because of this attribute. It adds some nice “conventions” for you that it will try and infer the FromBody, FromRoute, FromQuery etc for you. Generally speaking, I don’t see this breaking API’s, and for the most part, I use it everywhere. But if you are comparing two projects with the exact same controller and action setup, and one works and one doesn’t, it’s worth checking if one implements the ApiController attribute. Again, “Ctrl + Shift + F” is your friend here to find anywhere that it may be getting applied.
The post Solving HTTP 415 Errors In .NET Core appeared first on .NET Core Tutorials.
| https://online-code-generator.com/solving-http-415-errors-in-net-core/ | CC-MAIN-2022-40 | refinedweb | 998 | 61.16 |
Day_0<<
Lots Of Leds
I ordered a lol-shield for my arduino a while ago. Yesterday I finally found the time to solder the 133 leds :-)
I had no time to write any code for it yet, but I ran the example scripts from the LolShield Library and it works quite well.
so stay tuned for some led-blinking madness :-)
Getting Started with the VideoGameShield
The VideoGameShield from Wayne&Layne is a arduino-shield that allows you to write videogames that run on your TV using an arduino and a Wii-Nunchuck or Classic Game Controller.
This is a short tutorial that helps you on your first steps after you have solderd your kit following these instructions.
To draw on the screen the VGS uses the TVout library. In this example I use a Nunchuck as controller. first we include all the libraries that are needet to use TVout and Nunchuck
#include <TVout.h> #include <fontALL.h> #include <i2cmaster.h> #include <nunchuck.h>
then we define the structures we need to access the libraries
read more ...read more ...
Nunchuck n; TVout TV;_4<<
_6<<
and here are some smileys i generated
read more ...
Using an arduino as a AVR Programmer
I managed to use an arduino as an isp programmer for my ATTiny13. I first i tried to use the avr910 program described in this blogpost from Randall Bohn, but avrdude could not flash my hex file :-/
then i found a newer version of the code that emulates an avrisp at googlecode
read more ...
...
Adrduino Counter with lcd Display
I made a small device that has 3 independent counters which are shown on a lcd-display. The device uses an arduino and has 3 buttons on the front that are debounced in software and used to increment a variable. The variables are printed on a 1x16 char lcd-display.
the red switch on the side is a power-switch.
i really like the "frankenstein"-look of the eclosure :-)read more ..._15<<
read more ...
5_17<<
read more ...
| http://www.local-guru.net/blog/tag/arduino?page=2 | CC-MAIN-2017-13 | refinedweb | 336 | 81.33 |
Last week we looked at branching and conditionals logic and how we can rewrite these constructs as multi-clause functions to make our code more declarative and easier to understand and read.
If you are coming to Elixir from another programming language you are probably very accustomed to using loops to iterate through a list of items.
Something that may surprise you about Elixir is, there are no constructs for
while or
do...while.
Instead, Elixir prefers to use recursion to achieve dynamic looping. In today’s tutorial we will look at recursion.
How does recursion work in Elixir?
So if we don’t have the
while construct in Elixir, how do you iterate through a list?
The answer is our new favourite partnership of pattern matching and multi-clause functions!
First you define the clause that will be the last step of the process. Typically this will handle the situation when the list is empty.
Next you define more generic clauses that you can call recursively to iterate through the list.
For example, imagine we have a module that will print each element of a list:
defmodule MyList do def read([]), do: IO.puts("End of list") def read([head | tail]) do IO.puts(head) read(tail) end end
Firstly, we define a function that will deal with the last step of the process. In this example we have a
read/1 function that matches an empty list. If the list is empty we will print a message to alert the user.
Second, we define a more generic function that accepts a non-empty list.
We pattern match the list into the
head and the
tail and we print the
head.
Finally we call the
read/1 function again with the
tail.
If the
tail contains elements it will pattern match against the second definition. But if the list is empty the call to the
read/1 function will pattern match to the first definition which will print the final message and end the recursion.
So as you can see, we can effectively loop through the list using pattern matching, multi-clause functions and recursively calling the same function.
Again, as with last week, although this involves writing multiple functions, this approach has many benefits.
Firstly, your code is a lot more declarative. You can see what will happen when the list is empty verses if the list is not empty.
And secondly you can deal with each step of the process as a single, simple function definition.
What is Tail Call Optimisation?
If you’ve ever read into functional programming you may have heard the term “Tail Call Optimisation”. Unless you’ve really been digging into a functional programming language in the past, you have probably no idea what this even means, I know I certainly didn’t!
I’ll try and explain the concept here.
When you recursively call a function, the computer will allocate memory for every element in the list. This is probably going to be fine for a small list, but in the case of a really big list, you might run out of memory!
For example, here is an example of a Module for adding each element of a list together and return the total:
defmodule MyList do def sum([]), do: 0 def sum([head | tail]) do head + sum(tail) end end MyList.sum([1,2,3]) |> IO.puts
As you can see, first we define the empty list clause. In this case we return
0 for an empty list.
Next we define the non-empty clause that will be recursively called. This function splits the list into the
head and the
tail and then it returns the value of adding the
head and the return value from the
sum/1 function when given the
tail.
If you run this code you should see it produce the correct answer of
6.
So what’s the problem with this and where does Tail Call Optimisation come in?
If you were to run this function with a very big list of numbers you would eventually run out of memory. As I mentioned earlier, this is because the computer needs to allocate memory for each element in the list as the function is called recursively.
The solution to this problem is to slightly rewrite the function to take advantage of Tail Call Optimisation.
Tall Call Optimisation is where if the last thing a function does is call another function, the compiler can jump to the other function and then back again without allocating any additional memory.
The Erlang compiler will do this automatically because it will recognise the tail call, we just need to write out code in a certain way to take advantage of this optimisation.
This is great for recursive functions because it can run for a very large list without allocating any additional memory.
The reason why the example from above does not take advantage of tail call optimisation is because the last thing that occurs in the function is not a call to another function.
def sum([head | tail]) do head + sum(tail) end
As you can see, the last thing that happens is the addition between the return value from the
sum/1 call and the
head.
Lets rewrite this function to take advantage of tail call optimisation:
defmodule MyList do def sum([], accumulator), do: accumulator def sum([head | tail], accumulator) do sum(tail, head + accumulator) end end MyList.sum([1,2,3], 0) |> IO.puts
First we define the
sum/1 empty list clause that will simply return the accumulator that is passed in.
Next we define the non-empty list clause that will recursively call itself, each time taking the
head and adding it to the
accumlator until the list is empty.
Examples of recursion in Elixir
Lets take a look at a couple of more examples of writing recursive functions in Elixir.
First, here is an example of doubling each value in a list:
defmodule MyList do def double([]), do: [] def double([head | tail]) do [head * 2 | double(tail)] end end
This is pretty similar to the previous examples but instead of passing an accumulator we just return a new list with the head multiplied by 2.
Next, here is an example of only returning the even values from a list:
defmodule MyList do def evens([]), do: [] def evens([head | tail]) when rem(head, 2) == 0 do [head | evens(tail)] end def evens([_| tail]) do evens(tail) end end
Once again we first define the empty-list clause.
Next we define a clause that matches a non-empty list, but only when the
head is an even number. We then return a new list with the
head and a recursive call with the remaining tail.
Next we define the clause for a non-empty list when the
head is not an even number. Here we don’t care about the
head so we can just recursively call the
evens function with the remaining tail.
Finally, here is an example of a
map/2 function that takes a list an an anonymous function that will be applied to each element of the list:
defmodule MyList do def map([], _), do: [] def map([head | tail], func) do [func.(head) | map(tail, func)] end end MyList.map([1,2,3], &(&1 * &1))
Once again we first define the empty state clause that will simply return the empty list.
Next we define the general non-empty clause that will call the function on the head and then pass the tail and the function back into the
map/2 function to be called recursively until the list is empty.
The anonymous function in this example will simply multiply each element by itself.
If this anonymous function definition looks a bit strange to you, take a look at Functions as First-Class Citizens in Elixir.
Conclusion
Recursion is an important aspect of learning Elixir and is probably not something you do that often if you are coming from from another programming language.
Tail call optimisation is another important thing to understand as you could come across a situation where you are running out or memory due to how memory is allocated for each element of your list.
However, you probably won’t write these types of functions because they’re already available to you via the
Enum module. But it’s still worth understanding what’s going on in case you do. | https://www.culttt.com/2016/06/06/understanding-recursion-tail-call-optimisation-elixir/ | CC-MAIN-2018-51 | refinedweb | 1,409 | 68.4 |
Results 1 to 3 of 3
Thread: import mail to exim
- Join Date
- Sep 2009
- 3
import mail to exim
I have just purchased a vps with a new hosting company. Can anyone tell me if it is possible to import emails in to exim?
The only access to email I have with my previous company is through pop/imap. No access to a specific mail directory.
Regards,
Colin
If the new server already has an imap server, then this comes to mind.
Imapsync: an IMAP migration tool ( release 1.452 )You must always face the curtain with a bow.
Note, that this has less to do with exim and more with the two imap serversYou must always face the curtain with a bow. | http://www.linuxforums.org/forum/red-hat-fedora-linux/181205-import-mail-exim.html | CC-MAIN-2016-50 | refinedweb | 124 | 81.33 |
Introduction to JSON in Python
It is a format for storing data. JSON is referred to as JavaScript Object Notation. It is a lightweight data frame as compared to XML or HTML format. It is simple to understand and looks the same as dictionaries in Python with some minor differences like (Boolean notation and Null notation). Nowadays JSON is a very common data format for storing data/ Fetching data from APIs and for configuration files. The JSON format is language independent and is adaptable in python as well. In the case of Python, it has a separate library called JavaScript Object Notation.
How JSON Works in Python?
As we know that Jason is basically a file format to store the data, now with the help of we can use existing JSON file or create a new python dataset and assign it in JSON format. The Syntax for each operation is discussed below.
1. Importing JSON Library in Python
Python uses the JavaScript Object Notation library. To Install the library the syntax is given below.
Syntax:
Pip install jsonlib ;
pip install demjson
Once you have a library in python, write the following command for importing it into code.
Import json;
2. Get or Load JSON Format Dataset
To load JSON format data the following syntax is used as given below.
Syntax:
My_json = json.load( Mason )
In parenthesis write the name of the file you want to load.
3. Perform Operations on It
Json format is like dictionaries of python with some minor differences. We can perform several operations that we can perform on python dictionaries like viewing datasets, using loops, changing values, aggregating different keys to create a new key, etc.
4. Return JSON Format from Python
When we load the JSON file into python it is converted to python readable format and is being worked upon. Once the file is ready it is again converted to original Json format.
To do this we use the following Syntax as given below:
Syntax:
My_json_output = json.dump( Mjson )
In parenthesis write the name of the file you would like to dump.
How to Convert JSON to Python and Python to JSON?
This is the most important part of this article. To convert a JSON document into python we perform Deserialization or Decoding. To convert a python document into json string we perform Serialization or Encoding. To perform these two operations, we need a library called demjson.
Basically, what Serialization and Deserialization do is, it provides a translator which in return encodes and decodes the format. The below table shows the relation between python and json.
Here we can see there are some differences which we can identify clearly that are numbers in json are treated as int and float and null in json is treated as None in Python, an object in json are dictionaries in python and so on. We will see the conversion in detail in the example section.
Examples to Implement JSON in Python
Here are the examples to implement JavaScript Object Notation in python as follows:
1. Encoding / Serialization to JSON File
The task is to create one normal python dictionary and then encode the same into a json file. Here we will take None and false type from python and we will observe how the same has been changed in a json file.
Code:
Import json
#Creating a Dictionary Dataset in python
Mjson= { 'City' : ['Hyd' , 'Delhi' , 'Bombay' , 'Indore', None],
'Food' :['Biryani', 'Momos' , 'Vadapav' , 'Poha' , False]}
# Encoding to json file.
with open("Mjson.json", "w") as write_file:
json.dump(Mjson, write_file)
After executing this code check in the directory of python code, the Mjson.json file would have been created.
Output:
{“City”: [“Hyd”, “Delhi”, “Bombay”, “Indore”, null], “Food”: [“Biryani”, “Momos”, “Vadapav”, “Poha”, false]}
Observe None is changed to null and False is changed to false.
2. Decoding / Deserialization to Python
The Mjson file which we just now have created now we will decode the same to python again. We will observe the previous observation once again.
Code:
import json;
# Decoding json into python
Import json
with open("Mjson.json", "r") as read_file:
My_python = json.load(read_file)
My_python
The output of the above will be our python dictionary. Observe again the null is converted to None.
Output:
{‘City’: [‘Hyd’, ‘Delhi’, ‘Bombay’, ‘Indore’, None], ‘Food’: [‘Biryani’, ‘Momos’, ‘Vadapav’, ‘Poha’, False]}
3. Formatting of JSON String Using Python Encoder
While encoding json, we can use some specified format defined so as to maintain clarity & format of data. Here we will use separators, indent and sort keys. As we already have a json file with us, we will modify the existing one.
Code:
with open("Mjson.json", "w") as write_file:
json.dump(Mjson, write_file, indent= 4, sort_keys =True, separators = (" | " , " = " ) )
Output:
{
“City” = [
“Hyd” |
“Delhi” |
“Bombay” |
“Indore” |
null
] |
“Food” = [
“Biryani” |
“Momos” |
“Vadapav” |
“Poha” |
false
] }
It’s purely the choice of coder how json format is required.
Advantages
Let see some of the advantages of Python JavaScript Object Notation in detail given below:
- JSON is a formation to transfer data from server to client and vice versa. HTML and XML provide static data, while most of the data we need is dynamic, in this case, JSON can help.
- When an Asynchronous request is sent to a server via browser or application. The Server receives the request and returns data (what format any format is fine, the client needs data only). Now if the format is Html format, it will give design as well as data, but the client already has design it needs only data.
- In the server, the data will be in the form of objects with properties, so it makes data as complex data type objects. Now for this, we have JSON (JavaScript Object Notation).JavaScript Object Notation makes it easy to process complex data with multiple classes and objects.
- It is of utmost need to use json type in DS and ML research, python provides solutions for the same. Server Serialise the objects and the client de-serialize the object and read it.
Conclusion
Json is a format and is generally produced from different java-scripts and APIs which are on JS. With the help of python, one can communicate with json files. In python Deserialization or decoding is used to convert a json object into a python dictionary and Serialization or encoding is used for converting python doc into a json object. This article covers both and also which format the programmer wants can choose it.
Recommended Articles
This is a guide to the JSON in Python. Here we discuss how JSON works in Python along with various examples and its advantages in detail. You may also look at the following articles to learn more- | https://www.educba.com/json-in-python/ | CC-MAIN-2021-04 | refinedweb | 1,113 | 64.1 |
In our previous post on optimizing tagless final programs we learned how we could use the sphynx library to derive some optimization schemes for your tagless final code. In case you missed it and want to read up on it, you can find it right here or you can watch my presentation on the topic here, but you should be able to follow this blog post without going through it all in detail.
One of the questions I’ve been getting a lot, is if we can also do something like that for the monadic parts of our program. The answer is yes, we can, however it will have to be quite a bit different.
I don’t think the differences are quite obvious, so we’ll go through them step by step.
With applicative programs, we’re optimizing a bunch of independent instructions.
That means, we can look at all of them and extract information out of them statically (i.e. without running the interpreter).
They can be seen as a sequence of instructions that we can fold down to a single monoid
M, that holds the information that we need to optimize.
We then used that monoid to recreate a new interpreter that can take this extra information into account.
With monadic programs, we do not have such luxury.
We can only step through each of our instructions one at a time, because every instruction depends on the results of the prior one.
This means that we cannot extract any information beyond the very first instruction we have.
That might seem like a deal breaker, but there’s still a few things we can do.
We could, for example, build up our monoid
M dynamically, after each monadic instruction.
Then, before invoking the next computation in the monadic sequence, we could take that monoid and recreate that next computation with that extra information.
Now, that might sound super abstract to you, and I wouldn’t disagree, so let’s look at a quick example.
Say, we’re using the
KVStore algebra again from last time:
trait KVStore[F[_]] { def get(key: String): F[Option[String]] def put(key: String, value: String): F[Unit] }
We could optimize programs with this algebra by caching the results of
get and we could use that same cache to also cache key-value pairs we inserted using
put.
So given this example program:
def program[F[_]: Monad](key: String)(F: KVStore[F]): F[List[String]] = for { _ <- F.put(key, "cat") dog <- F.get(key) cat <- F.get(dog.getOrElse("dog")) cat2 <- F.get("cat") } yield List(dog, cat, cat2).flatten
The naively interpreted program would be doing the following things:
keypassed by the user
Now if accessing the key-value store means going through a network layer this is of course highly inefficient. Ideally our fully optimized program should do the following things:
keyparameter passed by the user and cache it.
key
Cool, next, let’s look at how we might get there.
First the type of our cache, which for our case can just be a
Map[String, String], but generically could just be any monoid.
Now what we want to do is transform any interpreter for
KVStore programs into interpreters that
getaction with the actual interpreter
getor
putaction.
So how can we get there? It seems like we want to thread a bunch of state through our program, that we want to both read and write to.
If you’re familiar with FP folklore you might recognize that that description fits almost exactly to the
State monad.
Furthermore, because we know that our
F[_] is a monad, that means the
StateT monad transformer over
F will also be a monad.
Okay with that said, let’s try to develop function that turns any interpreter
KVStore[F] into an interpreter into
StateT[F, M, A], so an
KVStore[StateT[F, M, ?]], where
M is the monoid we use to accumulate our extracted information.
We’ll start with the
put operation.
For
put, we’ll want to call the interpreter to perform the action and then modify the state by adding the retrieved value into our cache.
To make the code a bit more legible we’ll also define a few type aliases.
type Cache = Map[String, String] type CachedAction[A] = StateT[F, Cache, A] def transform(interp: KVStore[F]): KVStore[CachedAction] = new KVStore[CachedAction] { def put(key: String, v: String): CachedAction[Unit] = StateT.liftF[F, Cache, Unit](interp.put(key, v)) *> StateT.modify(_.updated(key, v)) def get(key: String): CachedAction[Option[String]] = ??? }
So far, so good, now let’s have a look at what to do with the
get function.
It’s a bit more complex, because we want to read from the cache, as well as write to it if the cache didn’t include our key.
What we have to do is, get our current state, then check if the key is included, if so, just return it, otherwise call the interpreter to perform the
get action and then write that into the cache.
def get(key: String): CachedAction[Option[String]] = for { cache <- StateT.get[F, Cache] result <- cache.get(key) match { case s @ Some(_) => s.pure[CachedAction] case None => StateT.liftF[F, Cache, Option[String]](interp.get(key)) .flatTap(updateCache(key)) } } yield result def updateCache(key: String)(ov: Option[String]): CachedAction[Unit] = ov match { case Some(v) => StateT.modify(_.updated(key, v)) case None => ().pure[CachedAction] }
This is quite something, so let’s try to walk through it step by step.
First we get the cache using
StateT.get, so far so good.
Now, we check if the key is in the cache using
cache.get(key).
The result of that is an
Option[String], which we can pattern match to see if it did include the key.
If it did, then we can just return that
Option[String] by lifting it into
CachedAction using
pure.
If it wasn’t in the cache, things are a bit more tricky.
First, we lift the interpreter action into
CachedAction using
StateT.liftF, that gives us a
CachedAction[Option[String]], which is already the return type we need and we could return it right there, but we still need to update the cache.
Because we already have the return type we need, we can use the
flatTap combinator.
Then inside the
updateCache function, we take the result of our interpreter, which is again an
Option[String], and update the cache if the value is present.
If it’s empty, we don’t want to do anything at all, so we just lift unit into
CachedAction.
In case you’re wondering
flatTap works just like
flatMap, but will then
map the result type back to the original one, making it a bit similar to a monadic version of the left shark (
<*) operator, making it very useful for these “fire-and-forget” operations.
It’s defined like this:
def flatTap[F[_]: Monad, A, B](fa: F[A])(f: A => F[B]): F[A] = fa.flatMap(a => f(a).map(b => a))
And with that we now have a working function to turn any interpreter into an optimized interpreter.
We can also generalize this fairly easily into a function that will do all of the wiring for us.
To do so, we’ll generalize away from
KVStore and
Cache and instead use generic
Alg[_[_]] and
M parameters:
def optimize[Alg[_[_]], F[_]: Monad, M: Monoid, A] (program: MonadProgram[Alg, A]) (withState: Alg[F] => Alg[StateT[F, M, ?]]): Alg[F] => F[A] = interpreter => program(withState(interpreter)).runEmptyA
Just like last time, we have to use a
MonadProgram wrapper around
Alg[F] => F[A], because Scala lacks rank-N types which would allow us to define values that work over ALL type constructors
F[_]: Monad (Fortunately however, this will very probably soon be fixed in dotty, PR here).
Now let’s see if we can actually use it, by checking it with a test interpreter that will print whenever we retrieve or insert values into the
KVStore.
optimize[KVStore, IO, Cache, List[String]](program("mouse"))(transform) .apply(printInterpreter) .unsafeRunSync() // Put key: mouse, value: cat // Get key: cat
It works and does exactly what we want! Nice! We could end this blog post right here, but there’s still a couple of things I’d like to slightly alter.
As you were able to tell the implementation of our transformation from the standard interpreter to the optimized interpreter is already quite complex and that is for a very very simple algebra that doesn’t do a lot.
Even then, I initially wrote an implementation that packs everything in a single
StateT constructor to avoid the overhead of multiple calls to
flatMap, but considered the version I showed here more easily understandable.
For more involved algebras and more complex programs, all of this will become a lot more difficult to manage.
In our last blog post we were able to clearly separate the extraction of our information from the rebuilding of our interpreter with that information.
Let’s have a look at if we can do the same thing here.
First we’ll want to define an extraction method.
For applicative programs we used
Const[M, ?], however that cannot work here, as
Const doesn’t have a
Monad instance and also, because for extraction with monadic programs, we need to actually take the result of the computation into account.
That means, that for every operation in our algebra, we want a way to turn it into our monoid
M.
With that said, it seems we want a function
A => M, where
A is the result type of the operations in our algebra.
So what we can do here is define an algebra for
? => M, in types an
Alg[? => M].
Let’s try to do define such an interpreter for our
KVStore along with
Cache/
Map[String, String:
def extract: KVStore[? => Cache] = new KVStore[? => Cache] { def get(key: String): Option[String] => Cache = { case Some(s) => Map(key -> s) case None => Map.empty } def put(key: String, a: String): Unit => Cache = _ => Map(key -> a) }
Just as before we want to extract the cache piece by piece with every monadic step.
Whenever we get an
Option[String] after using
get, we can then turn that into a
Cache if it’s non-empty.
The same goes for
put, where we’ll create a Map using the key-value pair.
We now have a way to turn the results of our algebra operations into our information
M, so far so good!
Next, we’ll need a way to rebuild our operations using that extracted information.
For that, let’s consider what that actually means.
For applicative programs this meant a function that given a state
M and an interpreter
Alg[F], gave a reconstructed interpreter inside the
F context
F[Alg[F]].
So a function
(M, Alg[F]) => F[Alg[F]].
For monadic programs, there’s no need to precompute any values, as we’re dealing with fully sequential computations that can potentially update the state after every evaluation.
So we’re left with a function
(M, Alg[F]) => Alg[F].
Let’s try building that for
KVStore:
def rebuild(m: M, interp: KVStore[F]): KVStore[F] = new KVStore[F] { def get(key: String): F[Option[String]] = m.get(key) match { case o @ Some(_) => Monad[F].pure(o) case None => interp.get(key) } def put(key: String, a: String): F[Unit] = m => interp.put(key, a) }
Easy enough!
For
get we look inside our cache and use the value if it’s there, otherwise we call the original interpreter to do its job.
For
put, there’s nothing to gain from having access to our extracted information and the only thing we can do is call the interpreter and let it do what needs to be done.
Now we have a way to extract information and then also use that information, next up is finding a way to wire these two things together to get back to the behaviour we got using
StateT.
And as a matter of fact, we’ll wire them back together using exactly
StateT, as it’s monad instance does do exactly what we want.
Using our two functions
extract and
rebuild it’s fairly easy to get back to
KVStore[StateT[F, Cache, ?]]:
def transform(interp: KVStore[F]): KVStore[StateT[F, Cache, ?]] = new KVStore[StateT[F, Cache, ?]] { def put(key: String, v: String): StateT[F, Cache, Unit] = StateT(cache => rebuild(cache, interp).put(key, v).map(a => (cache |+| extract.put(key, v)) -> a)) def get(key: String): StateT[F, Cache, Option[String]] = StateT(cache => rebuild(cache, interp).get(key).map(a => (cache |+| extract.get(key)) -> a)) }
This is fairly straightforward, we use rebuild with our cache and the interpreter to get a new interpreter that will run the operation.
Then, we use the result, which is just an
F[Unit]/
F[Option[String]] respectively, and map it
using the extractor to get the newest
Cache and using its
Monoid instance to update the state and then we tuple it with the result, giving us an
F[(Cache, Unit)] or
F[(Cache, Option[String])], which is exactly what the
StateT constructor needs.
This is great, but can we generalize this to any algebra and any monoid?
The answer is yes, but it’s not exactly easy.
First let’s look at the actual problem.
We have two interpreters
extract and
rebuild, but we have no way to combine them, because
Alg, is completely unconstrained and that means we can’t call any functions on a generic
Alg[F] at all.
So, okay, we need to constrain our
Alg parameter to be able to combine values of
Alg[F] with values of
Alg[G] in some way, but what kind of type class could that be?
Are there even type classes that operate on the kind of
Alg?
There are, they’re just hidden away in a small library called
Mainecoon.
That library gives us higher kinded versions of things like functors and contravariant functors, called
FunctorK and
ContravariantK respectively.
Let’s have a quick look at
FunctorK:
@typeclass trait FunctorK[A[_[_]]] { def mapK[F[_], G[_]](af: A[F])(f: F ~> G): A[G] }
Instead of mapping over type constructors
F[_], we map over algebras
A[_[_]] and insteading of using functions
A => B, we use natural transformations
F ~> G.
This is nice, but doesn’t really get us that far.
What we really need is the equivalent of the
Applicative/
Apply
map2 operation.
map2 looks like this:
def map2[A, B, C](fa: F[A], fb: F[B])(f: (A, B) => C): F[C]
And a higher kinded version would look like this:
def map2K[F[_], G[_], H[_]](af: A[F], ag: A[G])(f: Tuple2K[F, G, ?] ~> H): A[H]
If you haven’t guessed yet
Tuple2K is just a higher kinded version of
Tuple2:
type Tuple2K[F[_], G[_], A] = (F[A], G[A])
Unfortunately
Mainecoon doesn’t have an
ApplyK type class that gives us this
map2K operation, but it gives the next best thing!
A higher-kinded
Semigroupal, which when combined with the higher kinded
Functor gives us that higher kinded
Apply type class.
It’s called
CartesianK (because cats
Semigroupal used to be called
Cartesian, but is renamed to
SemigroupalK in the next version) and looks like this:
@typeclass trait CartesianK[A[_[_]]] { def productK[F[_], G[_]](af: A[F], ag: A[G]): A[Tuple2K[F, G, ?]] }
Now just like you can define
map2 using
map and
product we can do the same for
map2K:
def map2K[F[_], G[_], H[_]](af: A[F], ag: A[G])(f: Tuple2K[F, G, ?] ~> H): A[H] = productK(af, ag).mapK(f)
Okay, after that quick detour, let’s have a look at how can make use of these type classes.
If we look at what we have and how we’d like to use the
map2K function, we can infer the rest that we need quite easily.
We have an
Alg[F] and a
Alg[? => M], and we want an
Alg[StateT[F, M, ?]], so given those two as the inputs to
map2K, all that seems to be missing is the natural transformation
Tuple2K[F, ? => M, ?] ~> StateT[F, M, ?].
Nice! As so often, the types guide us and show us the way.
Well let’s try to define just that:
new (Tuple2K[F, ? => M, ?] ~> StateT[F, M, ?]) { def apply[A](fa: Tuple2K[F, ? => M, ?]): StateT[F, M, A] = StateT(m => F.map(fa.first)(a => M.combine(fa.second(a), m) -> a)) }
This looks good, but actually has a problem, to get an
Alg[F] from
rebuild we give it an
M and an interpreter
Alg[F].
The interpreter isn’t really a problem, but the
M can prove problematic as we need to give it to the
rebuild function after each monadic step to always receive the latest state.
If we look at our natural transformation above, that function will never receive the newest state.
So what can we do about this?
Well, we could be a bit more honest about our types:
type FunctionM[A] = M => F[A] def rebuild(interp: Alg[F]): Alg[FunctionM]
Hey, now we’re getting there. This works, but if we look into some of the data types provided by
Cats we can acutally see that this is just
Kleisli or
ReaderT, so our
rebuild should actually look like this:
def rebuild(interp: Alg[F]): Alg[Kleisli[F, M, ?]]
And now, we can easily implement a correct version of that natural transformation from earlier:
new (Tuple2K[Kleisli[F, M, ?], ? => M, ?] ~> StateT[F, M, ?]) { def apply[A](fa: Tuple2K[Kleisli[F, M, A], ? => M, ?]): StateT[F, M, A] = StateT(m => F.map(fa.first.run(m))(a => (fa.second(a) |+| m) -> a)) }
Cool, then let us also adjust the rebuild function we created for
KVStore:
def rebuild(interp: KVStore[F]): KVStore[Kleisli[F, M, ?]] = new KVStore[Kleisli[F, M, ?]] { def get(key: String): Kleisli[F, Cache, Option[String]] = Kleisli(m => m.get(key) match { case o @ Some(_) => Monad[F].pure(o) case None => interp.get(key) }) def put(key: String, a: String): Kleisli[F, Cache, Unit] = Kleisli(m => interp.put(key, a)) }
It’s stayed pretty much the same, we just needed to wrap the whole thing in a
Kleisli and we’re good!
Now we can go ahead and define the full function signature:
def optimize[Alg[_[_]]: FunctorK: CartesianK, F[_]: Monad, M: Monoid, A] (program: MonadProgram[Alg, A]) (extract: Alg[? => M]) (rebuild: Alg[F] => Alg[Kleisli[F, M, ?]]): Alg[F] => F[A] = { interpreter => val tupleToState = new (Tuple2K[Kleisli[F, M, ?], ? => M, ?] ~> StateT[F, M, ?]) { def apply[A](fa: Tuple2K[Kleisli[F, M, A], ? => M, A]): StateT[F, M, A] = StateT(m => F.map(fa.first.run(m))(a => (fa.second(a) |+| m) -> a)) } val withState: Alg[StateT[F, M, ?]] = map2K(extract(interpreter), rebuild))(tupleToState) program(withState).runEmptyA }
That is all, we’ve got a fully polymorphic function that can optimize monadic programs.
Let’s use it!
optimize(program)(extract)(rebuild) .apply(printInterpreter) .unsafeRunSync()
Now, when we run this, it should be exactly the same result as when we ran it earlier using the direct
StateT interpreter, but the resulting code is much cleaner.
However, it does have the drawback that you’ll now need additional constraints for every algebra to use this function.
That said though, one of the cool features of
Mainecoon is that it comes with auto-derivation.
Meaning we can just add an annotation to any of our algebras and it will automatically derive the
FunctorK and
CartesianK instances.
In fact, that is exactly how I defined those two instances for the
KVStore algebra:
@autoFunctorK @autoCartesianK trait KVStore[F[_]] { ... }
This makes it fairly easy to use these extra type classes and helpts mitigate the drawbacks I mentioned.
Today we’ve seen a way to make optimizing monadic tagless final programs easier and intuitive, all the code is taken from the sphynx library and can be found right here, but might still be subject to change, because designing a good API is hard.
What do you think about this optimization scheme? Maybe you just prefer using
StateT and being done with it, or maybe you like to use a typeclass based approach like the one we used last time?
Would love to hear from you all in the comments!
Unless otherwise noted, all content is licensed under a Creative Commons Attribution 3.0 Unported License.Back to blog | https://typelevel.org/blog/2018/06/27/optimizing-tagless-final-2.html | CC-MAIN-2019-09 | refinedweb | 3,457 | 71.55 |
Project Templates
To standardize application code in terms of naming and structure and simplify the process of creating applications, DevExtreme comes with application templates integrated into Visual Studio. Using these templates, you will create mobile applications more quickly.
To create a project using one of the DevExtreme templates, select File | New | Project... from the Visual Studio main menu. This will take you to the New Project dialog.
In the Projects tree view, select DevExtreme. In the Templates list view, choose a project template, specify a name for it and click OK.
DevExtreme App Project Template
DevExtreme provides several project templates for building applications. These templates have different structure specific to the application purpose. However, all of these templates have a similar set of features characterizing the possessiveness of the templates to DevExtreme.
Project Context Menu
Here is the context menu that is invoked by right-clicking a DevExtreme project.
Properties
DevExtreme projects have general application properties. You can set them up within the Properties window. For details, refer to the Specify General Project Properties topic.
Manage NuGet Packages...
DevExtreme projects can be extended by external libraries that are distributed as NuGet packages. For this purpose, use the standard *Manage NuGet Packages... dialog.
Build Application Template...
DevExtreme applications are packed using the PhoneGap Build. For this purpose, DevExtreme applications have a default PhoneGap application template. If you are required to use a custom Cordova version or a custom set of PhoneGap plugins, you should build a custom PhoneGap application template to be used to pack your DevExtreme application. For this purpose, use the Build Application Template... wizard. For details, refer to the Build Custom PhoneGap Application Template topic.
Run Theme Builder...
DevExtreme comes with a set of predefined themes. Each theme is represented by CSS classes that are responsible for giving consistency to an application. You can customize these themes and make them specific to your application(s). For this purpose, use the Theme Builder.
Build Native Packages...
Applications built using the DevExtreme Project Templates can be easily packaged to be deployed to any device. For this purpose, use the Build Native Packages... wizard. For details on packaging, refer to the Packaging Tools article.
Project Specific Files
DevExtreme application projects have the following common files.
cordova.js
Initially, this is an empty file. When building a package, the Package Builder replaces this file with a valid platform specific Cordova library of the required version. For details on the Cordova version, refer to the Set Cordova Version topic.
config.xml
A file that is used by the Build Native Packages... wizard. This file is required to specify core Cordova API features, plugins, and platform-specific settings.
Simulation Tools
Applications built using DevExtreme project templates run in a browser with the help of the DevExtreme Simulator. To read more, refer to the Simulation Tools article.
Linking to Other Projects
You can deploy a DevExtreme project by linking it to another Visual Studio project - ASP.NET, WindowsPhone, Win8, etc. - and then deploy the latter using standard Visual Studio tools. To link a DevExtreme project to another project, use the Link to... dialog. To invoke this dialog, use the Link to... item in a context menu of the DevExtreme project. This menu item appears in the context menu when there is a non-DevExtreme project in the current solution.
For details on linking DevExtreme projects to other projects, refer to the Linking DevExtreme Projects article.
Basic Application
Basic Application is a project template for building an HTML/JS application based on the DevExtreme SPA Framework and DevExtreme widgets.
The Basic Application project has a basic structure that is common for applications based on the DevExtreme framework. This application structure is detailed in the Application Project article.
The .dxView files are the HTML files that can be opened using the View Designer. To learn more about the View Designer, refer to the Design-Time Features documentation section.
The app.config.js file includes the configuration object used to initialize the application object.
Generally, the basic project template is the minimum requirement for starting to build an application. You can then extend the project as required.
The application created using the Basic Application template can be built for the desktop or packaged for iOS, Android, Win8Phone and PhoneGap. For details, refer to the Packaging Tools documentation section.
Basic Application (Type Script)
Basic Application (Type Script) is the same as the Basic Application project. The only difference is that the TypeScript language is used in the Basic Application (Type Script) and the required Type Script libraries are referenced in it.
Multi-Channel Application
Multi-Channel Application is a project template for building an HTML/JS application based on the DevExtreme SPA Framework and DevExtreme widgets. This project template is more helpful than the Basic Application project template in the following cases.
Creating a Multi-Channel Solution
When you need to build different applications for desktop, iOS, Android, WindowsPhone8 and Windows8 using a shared code.
Creating an OData Bound Solution
No matter which platforms you are going to support, the application will be bound to an OData service.
When you select the Multi-Channel Application template in the New Project dialog, the DevExtreme Project Wizard runs. Using this wizard, you can create both a multi-channel solution and generate views for the entities from the specified OData service.
On the first page of the DevExtreme Project Wizard, choose the "channels" to be supported by the application by checking corresponding items.
In the image above, the Web and Mobile "channels" are chosen. The Win8 items are disabled when you don't work on Windows8. The WinPhone8 item is disabled when you don't work on Windows8 and don't have the Windows Phone 8.0 Developer Tools SDK installed.
The next Choose Layout step in the wizard allows you to choose the navigation layout to be used in the created applications by default.
After making the choice, click Next. You will go to the Choose Entities To Generate Views step. If you do not have an OData service for your applications, you can click Finish without specifying anything. In this instance a multi-channel solution will be generated with sample views.
If you are going to bind the application to an OData service and generate application views for entities, specify your OData Service by entering its URL or choosing the one that is already added to the current solution (if you add a DevExtreme project to a solution). Click Discover. A list of entities exposed by your service will be displayed. Check the entities for which you want to generate views.
Press Finish.
The following projects are created for the corresponding "channels" selected in the wizard.
These projects have the structure of a basic project template. If you specified an OData service to be used as a data source, views will be generated for the entities. View Models will be located in the db folder of the Shared project. Views and ViewModels are the .dxView and JavaScript files that will be added to the Views folder of the generated projects. The .dxView file is the HTML file that can be opened using the View Designer.
Shared Project
This project is always created, regardless of the "channel(s)" you chose in the DevExtreme Project Wizard. This project is referenced in all other projects because it contains shared code. For instance, if you have more than one project in your solution (e.g., mobile and win8 projects), the views that are intended for all of these projects can be defined once - within the Shared project. At the same time, you can modify a file in any project that references the Shared project. In this instance, the customized version will be used in the running project.
In the data folder, you can find the db.js file. In this file, a template for creating an ODataContext is realized. The ODataContext instance is created to communicate with an OData service. ODataContext creates a set of ODataStore objects inside to communicate with each entity provided by the OData service. To specify a URL to the required service and list the entities required for the application, a configuration object is passed as a parameter to the ODataContext constructor.
Application1.db = new DevExpress.data.ODataContext(serviceConfig.db);
In the project template, a configuration object is accessed as the object provided by the db field of the serviceConfig object. If you need to create an OData context for an additional OData service, add one more field to the serviceConfig object.
{ db: { url: endpointSelector.urlFor("db"), "entities": {}, errorHandler: handleServiceError } }
To get the required URL - for local or productional use - the urlFor("db") method of the endpointSelector object is called. This method returns a local URL if the application runs on a local host, otherwise a productional URL is returned. The possible URLs for the "db" service are specified in the endpointSelector's configuration object.
var endpointSelector = new DevExpress.EndpointSelector(Application1.config.endpoints); //see the application1.shared.config.js file "endpoints": { "db": { "local": "", "production": "" } },
If you specify a certain OData service and choose the required entities in the Project Wizard, the service URL and entities will be specified in the created project and the created ODataContext will be ready to use. Otherwise, an empty template for ODataContext will be created so that you can configure it manually.
If you are going to use a data service of another type, simply remove the default content from the db.js and application1.shared.config.js files. Learn how to provide data using the DevExtreme data layer in the Data Layer documentation section.
Desktop Project
This project is created when you choose Web in the DevExtreme Project Wizard and is intended to create an application for a desktop. For this purpose, it includes the Desktop built-in layout (see the Layouts folder), a generic light/dark predefined theme (see the css folder) and has a "webSite" application mode.
Generally, the Desktop project has the same structure as the basic project template. In addition, it references the Shared project, so the files (e.g., Views) from the Shared project are copied to the Desktop project. If the same files are found, the files from the Desktop project overwrite the files from the Desktop project.
Mobile Project
This project is created when you choose Mobile in the DevExtreme Project Wizard and is intended to create an application for mobile devices. For this purpose, it includes predefined layouts that are designed for Android, iOS and Win8Phone platforms, along with style sheets that are required for different mobile devices to give an application its native looks. You can define different views for different platforms and device forms. To learn how to do this, refer to the Views and Layouts article.
The application created using the Mobile project can be packaged for iOS, Android, Win8Phone and PhoneGap. To learn how to do this, refer to the Packaging Tools section.
Win8Phone Project
This project is created when you choose WinPhone8 in the DevExtreme Project Wizard and is intended for building mobile applications for the Win8Phone platform. This project is created using a standard template for Win8Phone applications. The Mobile project, however, is linked to its www folder. All the files in this folder represent links to corresponding files in the Mobile project. Use the Mobile project to create an application for Win8Phone, but build the Win8Phone project for deployment to the device.
To package an application created using the Win8Phone project, use procedures standard for WinPhone8 VS projects Packaging your Windows Store app using Visual Studio 2012).
Win8 Project
When choosing Win8 in the DevExtreme Project Wizard, a project for the Windows 8 platform is created. This project has a standard template for Win8 applications. In addition, this project has links to files from the Shared project. This makes it possible for you to develop a DevExtreme application for Windows 8.
To package an application created using the Win8 project, use standard procedures (see Packaging your Windows Store app using Visual Studio 2012).
WCF OData Service
To create a WCF ODATA Service, use the template that is provided by DevExtreme. When choosing the DevExtreme WCF OData Service template in the New Project dialog, a standard Entity Data Model Wizard runs. The project that is generated by this wizard is extended by CORS and JSONP support.
After you are finished with the OData service project, add a DevExtreme project to the solution using the Basic Application or Multi-Channel Application template. In the DevExtreme Project Wizard, you will be able to choose the OData service from the current solution and generate views for the entities exposed by this service.
Set a Custom Namespace
When you use a project template for an application, the application's namespace is generated automatically. You may need to use a custom namespace. In this topic, you will learn specific notes on how to set a custom namespace for the DevExtreme SPA Framework-based applications created using the Basic Application or Multi-Channel Application project templates.
To change the namespace of an application project on the stage on which the project has certain implemented content, do the following.
Change the application namespace.
Set the namespace option of the HTmlApplication project to the new namespace name.
Change the namespace of the functions implemented in the project.
In particular, pay attention to the functions that return ViewModel objects.
Set the new namespace for the views that will be added by the Add | New Item... dialog further.
The template that is used by the Add | New Item... dialog for creating views has a JavaScript file. In this file, there is a function that returns a ViewModel for the view. The namespace for this function is the project name by default. To change the default namespace to a custom one, use the Root namespace property of the application project.
AngularJS NavBar Application
AngularJS NavBar Application is a project template for building an HTML/JS application based on the AngularJS framework and DevExtreme widgets. In this project template, the dxNavBar NavBar Application template can be built for desktop or packaged for iOS, Android, Win8Phone and PhoneGap. For details, refer to the Packaging Tools documentation section.
AngularJS SlideOut Application
AngularJS SlideOut Application is a project template for building an HTML/JS application based on the AngularJS framework and DevExtreme widgets. In this project template, the dxSlideOut SlideOut Application template can be built for desktop or packaged for iOS, Android, Win8Phone and PhoneGap. For details, refer to the Packaging Tools documentation section. | https://js.devexpress.com/Documentation/15_1/Guide/VS_Integration/Project_Templates/ | CC-MAIN-2018-13 | refinedweb | 2,419 | 56.35 |
Opened 3 years ago
Closed 2 years ago
#5684 defect closed wontfix (wontfix)
OpenSSL.SSL.Connection object has no getpeername attribute
Description
When reactor.connectSSL is used to create an SSL connection, the OpenSSL.SSL.Connection object has no getpeername attribute.
The following code sample can be used to reproduce the problem (change the connectSSL arguments to a valid IP and port where a secure server is accepting connections).
from OpenSSL import SSL from twisted.internet import reactor, ssl from twisted.internet.protocol import ClientFactory from twisted.protocols.basic import LineReceiver class MyContextFactory(ssl.ClientContextFactory): def _verify(self, connection, x509, errnum, errdepth, ok): peername = connection.getpeername() print "connected to", peername return ok def getContext(self): ctx = ssl.ClientContextFactory.getContext(self) ctx.set_verify(SSL.VERIFY_PEER, self._verify) return ctx class MyClient(LineReceiver): def connectionMade(self): return def lineReceived(self): return class MyClientFactory(ClientFactory): protocol = MyClient def clientConnectionFailed(self, connector, reason): reactor.stop() def clientConnectionLost(self, connector, reason): reactor.stop() if __name__ == "__main__": reactor.connectSSL('10.1.2.3', 12345, MyClientFactory(), MyContextFactory()) reactor.run()
This produces an exception:
exceptions.AttributeError: 'NoneType' object has no attribute 'getpeername'
Yet this works...
from OpenSSL import SSL import socket context = SSL.Context(SSL.TLSv1_METHOD) s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) connection = SSL.Connection(context, s) connection.connect(('10.1.2.3', 12345)) print "connected to", connection.getpeername()
Change History (6)
comment:1 Changed 3 years ago by exarkun
- Owner set to nathanm
comment:2 Changed 3 years ago by nathanm
Using I still get the error. I'm running the latest Twisted 12.0.0 code from the svn repo. My pyOpenSSL version is 0.11. You're testing the first code sample, and not the second, correct?
comment:3 Changed 3 years ago by nathanm
I get the same result with pyOpenSSL version 0.13.
comment:4 Changed 3 years ago by exarkun
The difference is whether the Twisted memory bio-based transport implementation is in use or not.
Newer versions of Twisted don't let OpenSSL do networking. A consequence is that there is no Connection instance to pass to the verify callback (note that the object passed for the first argument is None, not a Connection object that is missing getpeername).
comment:5 Changed 3 years ago by nathanm
When memory BIO is in use, is there any way to ascertain peer name in the verify method?
comment:6 Changed 2 years ago by glyph
- Resolution set to wontfix
- Status changed from new to closed
You can use the self.transport.getPeer() method, since the "transport" attribute of Protocol is documented to be an ITransport, and an ITransport does not necessarily have a "socket" attribute.
This method has always worked, and is really how you ought to have been doing it all along.
I'm closing this as "wontfix" rather than "invalid", because in some cases this might be a valid observation about compatibility being broken - you didn't have to type "._" to get to it, which in many cases makes it fair game. However, in the case of an attribute with a documented interface, you really can't depend on more attributes than what the interface documentation says, if you want your code to keep working with new implementations of that interface, which the new BIO-based implementation is.
I fail to reproduce this problem. Changing the host/port to, I get this output: | http://twistedmatrix.com/trac/ticket/5684 | CC-MAIN-2015-11 | refinedweb | 564 | 50.53 |
User Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/17.0 Firefox/17.0 Build ID: 20120809002637 Steps to reproduce: 1. Installed libunwind 2. Tried to compile firefox with gcc42 or clang. Actual results: xpcom/base/nsStackWalk.cpp:1197:29: error: use of undeclared identifier '_Unwind_Backtrace' _Unwind_Reason_Code t = _Unwind_Backtrace(unwind_callback, &info); ^ 1 error generated. Expected results: Build succesfully.
Created attachment 650465 [details] [diff] [review] define _GNU_SOURCE for _Unwind_Backtrace
Comment on attachment 650465 [details] [diff] [review] define _GNU_SOURCE for _Unwind_Backtrace Unlike recent versions of GCC libunwind and libc++ put _Unwind_Backtrace under _GNU_SOURCE. However, configure script doesn't know this and just checks for the function in unwind.h irregardless of where it came from.
How did configure detect the function's presence if it's conditional on _GNU_SOURCE? (You deleted config.cache and reran configure when changing compilers, right?)
(In reply to David Baron [:dbaron] from comment #3) > How did configure detect the function's presence if it's conditional on _GNU_SOURCE? Configure script checks only header presence[1]. Then it goes to check libraries and finds that implicitly linked -lgcc_s provides _Unwind_Backtrace symbol. $ env -i PATH=$PATH gmake conftest -f /dev/null cc conftest.c -o conftest $ cat conftest.c #line 24094 "configure" #include "confdefs.h" /* System header to define __stub macros and hopefully few prototypes, which can conflict with char _Unwind_Backtrace(); below. */ #include <assert.h> /* Override any gcc2 internal prototype to avoid an error. */ /* We use char because int might match the return type of a gcc2 builtin and then its argument prototype would still apply. */ char _Unwind_Backtrace(); int main() { /* The GNU C library defines this for functions which it implements to always fail with ENOSYS. Some functions are actually named something starting with __ and the normal name is an alias. */ #if defined (__stub__Unwind_Backtrace) || defined (__stub____Unwind_Backtrace) choke me #else _Unwind_Backtrace(); #endif ; return 0; } [1] more correct check would likely use AC_TRY_COMPILE, e.g. dnl ======================================================== dnl = Support for gcc stack unwinding (from gcc 3.3) dnl ======================================================== if test -z "$SKIP_LIBRARY_CHECKS"; then AC_LANG_CPLUSPLUS AC_MSG_CHECKING([for _Unwind_Backtrace in unwind.h]) AC_TRY_COMPILE([#include <unwind.h>], [_Unwind_Backtrace(0,0)], AC_MSG_RESULT([found]), AC_TRY_COMPILE([#define _GNU_SOURCE #include <unwind.h>], [_Unwind_Backtrace(0,0)], AC_MSG_RESULT([needs -D_GNU_SOURCE]), AC_MSG_RESULT([not found]))) fi
On FreeBSD it usually is Blender port that pulls libunwind by default (CAMERATRACK option).
Note, clang has unwind.h since 3.1. The header is different from the one used by -stdlib=libc++, it doesn't need _GNU_SOURCE.
Comment on attachment 650465 [details] [diff] [review] define _GNU_SOURCE for _Unwind_Backtrace r=dbaron
Created attachment 650792 [details] [diff] [review] Bug 781457 - Define _GNU_SOURCE for _Unwind_Backtrace. r=dbaron
Green on Try: | https://bugzilla.mozilla.org/show_bug.cgi?id=781457 | CC-MAIN-2017-26 | refinedweb | 435 | 52.15 |
While
iisManager.Sites.Add("NewSite", "http", "*:8080:", "d:\\MySite");
iisManager.Update();
This basically creates an instance of the ServerManager class and uses the Add method in the Sites collection to create a new site named "NewSite" listening at port 8080 using http protocol and content files are at d:\MySite.
One thing to note is that calling Update is a requirement since that is the moment when we persist the changes to the configuration store.
After running this code you have now a site that you can browse using
Adding an Application to a site
iisManager.Sites["NewSite"].Applications.Add("/Sales", "d:\\MyApp");
iisManager.Update();
This sample uses the Sites collection Indexer to get NewSite site and uses the Applications collection to add a new application.
Creating a Virtual Directory Site
iisManager.Sites["NewSite"].Stop();
Recyciling an Application Pool
iisManager.ApplicationPools["DefaultAppPool"].Recycle();
Getting the list of executing requests.
That might possibly be the coolest thing I’ve ever seen IIS do.
Its Wonderful and very cool.
special thanks to Mr. carlos, Microsoft and Microsoft communities.
Waauuu, we will be saving so many lines of code and using this extensive.
Does this modify the (what used to be) metabase? When dealing with several web servers in a cluster, will I still need to sync the metabases (or .config files) across nodes, or can I finally centralize all this on a NAS via UNC?
Mark – IIS7 does not use the metabase to store configuration. It is totally within .config files.
There is a Legacy ABO Compatibility component (completely optional, but installed by default) which you can install to capture all legacy API calls to configure the metabase and transparently translate it into .config settings.
You will still need to synchronize config settings across servers in a cluster, though if you run the same command remotely it’d do the same.
I have yet to understand the need to have IIS read configuration from a UNC share vs ability to copy the same IIS configuration to multiple machines. They accomplish the same objective; you can view one as a local-cached version of the other. Central UNC share sounds cooler but is more fragile, so why???
In other words, suppose you get what you want — the "centralized" config file on NAS via UNC. All that means is that after IIS calls CreateFile to get a handle to the file, read/write to the file can now RANDOMLY fail as IIS works with various sections of the file (and underneath the scenes, network traffic is getting used to fulfill the read/write).
What should IIS do? Bail on first error? Bail after retrying 5 times in 5 seconds (but suppose you are modifying config — where do they go)? Cache the change locally and periodically propagate back to the UNC (but explain how this is any better than IIS reading local .config file and a separate "syncing" service periodically syncing changes between multiple locations?
In other words — please explain your real scenario and requirements, not how you think we should implement things.
//David.
What a NAS/UNC based configuration store (metabase) buys you is a way out of the replication scenario. However, there still exists the random fail issue as you described. Ideally, I’d like to see a realtime replication method similar to Active Directory. Here, there are multiple peer nodes, where any change is replicated to the other nodes. Maybe this can be accomplished via a pure in-memory database with replication via two-phase commit across IIS nodes. Maybe a heartbeat service between IIS nodes? Just brainstorming here.
– Mark
O Scott Guthrie, do time de produtos Web da Microsoft, escreveu um post bem interessante sobre as novidades…
Though IIS 7 still support WMI, ABO, etc administrative interface, but you will love this new managed…
Can you create AppPools with the new interface?
I’ve been beating myselft up for a couple of months trying to figure out how to create an app pool via the WMI interface. I’ve resorted to using ADSI, but I hear that’s going away…
Chris
How about adding a "re-read config files" function to allow central config storage and after editing the config, telling each machine to re-read the file to flush the servers internal cache?
Not a bad idea, considering change notification doesnt work on metabase.xml.
Прошли старые добрые деньки. Реестр закапывают в землю, бинарные форматы закапыв
Yes you can create application pools as well as enumerate, remove them and even recycle them.
ну и слава богу, тока блин, когда еще смогу перетащить клиентов на 7ку…
Carlos Aguilar, del equipo de IIS 7 y desarrollador de la nueva consola y el nuevo API de administración…
Before the boom of web and internet, HTTP was not so common is everyday life. When internet became more…
Is there a way to Push data to client (Push Server ) using IIS 7? (ex live stock update !)
IIS7 is a major upgrade of IIS, and will ship in both Windows Vista as well as Windows Longhorn Server. …
<a href=’ ‘>action movie downloads</a>
ServerManager iisManager = new ServerManager();
iisManager.Sites.Add("NewSite", "http", "*:8080:", "d:\MySite");
I think .Update() method is replaces with .CommitChanges()
More than a year ago I wrote about Microsoft.Web.Administration.dll and how it was a new API we were
Can this be used to manage remote IIS servers within the same AD group?
mick dot walker at gmail dot com
Yes, you can use it to manage IIS 7 running in Windows Vista SP1 or Windows Server 2008 but only from a client running Windows Vista SP1 or Windows Server 2008. The way to do it is creating a ServerManager like this:
ServerManager remoteManager = ServerManager.OpenRemote("yourServer");
More than a year ago I wrote about Microsoft.Web.Administration.dll and how it was a new API we were
Thanks for your reply Carlos.
Do you know where I can find some ‘good’ documentation on this?
Also is there anyway to control FTP settings for a Site?
When using FTP 7.0 with IIS 7.0 and using Microsoft.Web.Administration how do add ftp settings to a web site? Or do I have to manually edit the .config files xml to add it?
If not supported, would this feature be supported in future?
You can absolutely use Microsoft.Web.Administration for that, however you will either need to use the loosely typed model (ConfigurationSection, ConfigurationElement, etc) or you will need to create your own strongly typed classes for it.
For example if you want to set something in the site, you can use:
ConfigurationElement ftpServer =ServerManager.Sites["Default Web Site"].GetChildElement("ftpServer");
And then use that for anything you need, also FTP defines several sections as well that you can use GetSection() over a Configuration object.
IIS7伴随着Vista已经悄悄来临，学习的时候我也摘录了一些有关于此的文章。 不敢独享，还是贴出来大家共享吧！
Will this all be exposed to the (VB) scripting engine?
Hi Carlos,
How do I query the current memory usage of a Site?
Regards,
Marcel
Интересную тему для вордпресса? 🙂
Hi Carlos ,
I am facing that create a virtual director from C# code without having admin previliages the code is
System.DirectoryServices.DirectoryEntry oDE;
System.DirectoryServices.DirectoryEntries oDC;
System.DirectoryServices.DirectoryEntry oVirDir;
oVirDir = null;
try
{
// check whether to create FTP or IIS virtual directory
if (IsFTP)
{
oDE = new DirectoryEntry("IIS://" + deploymentServerName + "/MSFTPSVC/1/Root");
}
else
{
oDE = new DirectoryEntry("IIS://" + deploymentServerName + "/W3SVC/1/Root");
}
try
{
string directoryEntryNameStr = oDE.Name;
}
now tell me a solution when I can create a virtual directory without being admin to windows Vista.
I clicked IIS6.0 metadata and configuration compatibilty and manament from window feature on/off/
For security reasons you cannot add a virtual directory unless you are an administrator.
You can imagine that if a non-administrator was able to expose a random directory over the URL namespace of the site would be a bad idea.
本文翻译整理自CarlosAguilarMares的blog文章：Microsoft.Web.AdministrationinIIS7。
请注意本文的内容均基于WindowsVista…
Can we use the Microsoft.Web.Administration from a Windows Server 2008 to remotely manage IIS 6 running on Windows Server 2003? Where is the Microsoft.Web.Administration located? Is it part of .Net or Windows?
Unfortunately you can only use it to manage a Windows Vista, Windows Server 2008, Windows 7, and Windows Server 2008 R2 server.
It is not distributed with .net but instead is part of IIS.
Are they any major changes to the Microsoft.Web.Administration API’s in IIS 7.5?
I am using VS2008 on an XP machine and cannot see the Microsoft.Web.Administration namespace. I guess this is because it is part of IIS7, which is not on the development machine. The finished code is to run on an IIS 7 server. I’d like to create a reference but don’t know where to find one. Can anyone help please?
Thanks!
Update: I installed the IIS Remote Manager on the XP dev machine thinking I might get the dll with it, but it appears
Just wondering, How would one go about using this API to both View and Modify the contents of the IPGrant and/or Deny Table?
Could you be so kind as to give an explanation or hint?
@Philip, here is an example:
using(ServerManager serverManager = new ServerManager()) {
Configuration config = serverManager.GetApplicationHostConfiguration();
ConfigurationSection ipSecuritySection = config.GetSection("system.webServer/security/ipSecurity");
ConfigurationElementCollection ipSecurityCollection = ipSecuritySection.GetCollection();
ConfigurationElement addElement = ipSecurityCollection.CreateElement("add");
addElement["ipAddress"] = @"169.132.124.234";
ipSecurityCollection.Add(addElement);
serverManager.CommitChanges();
}
}
You can also learn more at the configReference where we have samples for all sections:…/ipSecurity
using (ServerManager mgr = new ServerManager())
{
Site site = mgr.Sites[siteName];
if (site != null)
{
Microsoft.Web.Administration.Application app = site.Applications[appName];
if (app == null)
{
Microsoft.Web.Administration.Application iisApplication =
site.Applications.Add(appName, ApplicationPath);
//sets the application to Classic .Net AppPool
iisApplication.ApplicationPoolName = "ASP.NET v4.0 wcf";
//mgr.ApplicationPools["DefaultAppPool"].Recycle();
}
anyone got a clue how to delete a virtual directory? with VirtualDirectories.Remove…. i cant get it to work
非常不错，但是最近我在开发一个使用IIS Express运行的控制本地系统自带的IIS的系统，问题出现了。
可以获取到站点信息，但是不能获取到Site.State、Stop、Start都不能使用，保异常为：未实现的方法。
但是该用VS开发服务器就没有这样的问题，难道是配置问题？不知道是什么原因，请求协助Email:yandavid@163.com.谢谢。
How do I get TARGETSITE (id for the website ) programmetically? Thx For example, get ID for MyWebSite?
Would love to be able to get code to delete 2 virtual directories/applications then check to see if application pool has any other apps assigned to it. If not, delete the app Pool.
I'm trying to create a virtual directory using C#. When try to add a reference to Microsoft.Web.Administration Namespace I can't find it in the list. Any clue?
And thanks for the great article.
How can I using Microsoft.Web.Administration in my asp.net web site.
I want create a web page to manager the iis.
How to assign a specific user credentials for a site in IIS 6.0 using Visual Studio help please
关于ASP.NET操作IIS7的范例，可以查阅
thanks
its not working for remote administration, any code is really appritiated
Error On remote machine?
Unauthorized Access Exception
i want a vb code that can query the iis metadata to give the list of site that has browsing directory enabled status .can anyone provide it???
Hi this is great, however I am sitting with a major headache and cannot for the love of me add the node
“”
to the file … do you perhaps have a solution? I had tried the below to no avail.
Configuration config = serverManager.GetWebConfiguration(“Default Web Site”);
ConfigurationSection applicationPoolsSection = config.GetSection(“system.web”);
ConfigurationElementCollection applicationPoolsCollection = applicationPoolsSection.GetCollection();
ConfigurationElement addElement = applicationPoolsCollection.CreateElement(“identity”);
addElement[“key”] = “impersonate”;
addElement[“value”] = “true”;
applicationPoolsCollection.Add(addElement);
serverManager.CommitChanges();
You need to make sure request the right section, in this case it is system.web/identity (the whole thing), you can figure that out looking into %windir%\system32\inetsrv\config\schema
So do:
using(ServerManager serverManager = new ServerManager()) {
Configuration config = serverManager.GetWebConfiguration(“Your Site”);
ConfigurationSection identitySection = config.GetSection(“system.web/identity”);
identitySection[“impersonate”] = true;
serverManager.CommitChanges();
} | https://blogs.msdn.microsoft.com/carlosag/2006/04/17/microsoft-web-administration-in-iis-7/ | CC-MAIN-2019-35 | refinedweb | 1,981 | 50.23 |
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Grok the GIL: How to write fast and thread-safe Python
Grok the GIL: How to write fast and thread-safe Python
We explore Python's global interpreter lock and learn how it affects multithreaded programs.
Subscribe now
When I was six years old, I had a music box. I'd wind it up, and a ballerina revolved on top of the box while a mechanism inside plinked out "Twinkle, Twinkle, Little Star." The thing must have been godawful tacky, but I loved that music box, and I wanted to know how it worked. Somehow I got it open and was rewarded with the sight of a simple device—a metal cylinder the size of my thumb, studded so that as it rotated, it plucked the teeth of a steel comb and made the notes.
Of all a programmer's traits, curiosity about how things work is the sine qua non. When I opened my music box to see inside, I showed that I could grow up to be, if not a great programmer, then at least a curious one.
It is odd, then, that for many years I wrote Python programs while holding mistaken notions about the global interpreter lock (GIL), because I was never curious enough to look at how it worked. I've met others with the same hesitation, and the same ignorance. The time has come for us to pry open the box. Let's read the CPython interpreter source code and find out exactly what the GIL is, why Python has one, and how it affects your multi-threaded programs. I'll show examples to help you grok the GIL. You will learn to write fast and thread-safe Python, and how to choose between threads and processes.
(For the sake of focus, I only describe CPython here—not Jython, PyPy, or IronPython. CPython is the Python implementation that working programmers overwhelmingly use.)
Behold, the global interpreter lock
Here it is:
static PyThread_type_lock interpreter_lock = 0; /* This is the GIL */
This line of code is in ceval.c, in the CPython 2.7 interpreter's source code. Guido van Rossum's comment, "This is the GIL," was added in 2003, but the lock itself dates from his first multithreaded Python interpreter in 1997. On Unix systems, PyThread_type_lock is an alias for the standard C lock, mutex_t. It is initialized when the Python interpreter begins:
void
PyEval_InitThreads(void)
{
interpreter_lock = PyThread_allocate_lock();
PyThread_acquire_lock(interpreter_lock);
}
All C code within the interpreter must hold this lock while executing Python. Guido first built Python this way because it is simple, and every attempt to remove the GIL from CPython has cost single-threaded programs too much performance to be worth the gains for multithreading.
The GIL's effect on the threads in your program is simple enough that you can write the principle on the back of your hand: "One thread runs Python, while N others sleep or await I/O." Python threads can also wait for a threading.Lock or other synchronization object from the threading module; consider threads in that state to be "sleeping," too.
When do threads switch? Whenever a thread begins sleeping or awaiting network I/O, there is a chance for another thread to take the GIL and execute Python code. This is cooperative multitasking. CPython also has preemptive multitasking: If a thread runs uninterrupted for 1000 bytecode instructions in Python 2, or runs 15 milliseconds in Python 3, then it gives up the GIL and another thread may run. Think of this like time slicing in the olden days when we had many threads but one CPU. I will discuss these two kinds of multitasking in detail.
Think of Python as an old mainframe; many tasks share one CPU.
Cooperative multitasking
When it begins a task, such as network I/O, that is of long or uncertain duration and does not require running any Python code, a thread relinquishes the GIL so another thread can take it and run Python. This polite conduct is called cooperative multitasking, and it allows concurrency; many threads can wait for different events at the same time.
Say that two threads each connect a socket:
def do_connect():
s = socket.socket()
s.connect(('python.org', 80)) # drop the GIL
for i in range(2):
t = threading.Thread(target=do_connect)
t.start()
Only one of these two threads can execute Python at a time, but once the thread has begun connecting, it drops the GIL so the other thread can run. This means that both threads could be waiting for their sockets to connect concurrently, which is a good thing. They can do more work in the same amount of time.
Let's pry open the box and see how a Python thread actually drops the GIL while it waits for a connection to be established, in socketmodule.c:
/* s.connect((host, port)) method */
static PyObject *
sock_connect(PySocketSockObject *s, PyObject *addro)
{
sock_addr_t addrbuf;
int addrlen;
int res;
/* convert (host, port) tuple to C address */
getsockaddrarg(s, addro, SAS2SA(&addrbuf), &addrlen);
Py_BEGIN_ALLOW_THREADS
res = connect(s->sock_fd, addr, addrlen);
Py_END_ALLOW_THREADS
/* error handling and so on .... */
}
The Py_BEGIN_ALLOW_THREADS macro is where the thread drops the GIL; it is defined simply as:
PyThread_release_lock(interpreter_lock);
And of course Py_END_ALLOW_THREADS reacquires the lock. A thread might block at this spot, waiting for another thread to release the lock; once that happens, the waiting thread grabs the GIL back and resumes executing your Python code. In short: While N threads are blocked on network I/O or waiting to reacquire the GIL, one thread can run Python.
Below, see a complete example that uses cooperative multitasking to fetch many URLs quickly. But before that, let's contrast cooperative multitasking with the other kind of multitasking.
Preemptive multitasking
A Python thread can voluntarily release the GIL, but it can also have the GIL seized from it preemptively.
Let's back up and talk about how Python is executed. Your program is run in two stages. First, your Python text is compiled into a simpler binary format called bytecode. Second, the Python interpreter's main loop, a function mellifluously named PyEval_EvalFrameEx(), reads the bytecode and executes the instructions in it one by one.
While the interpreter steps through your bytecode it periodically drops the GIL, without asking permission of the thread whose code it is executing, so other threads can run:
for (;;) {
if (--ticker < 0) {
ticker = check_interval;
/* Give another thread a chance */
PyThread_release_lock(interpreter_lock);
/* Other threads may run now */
PyThread_acquire_lock(interpreter_lock, 1);
}
bytecode = *next_instr++;
switch (bytecode) {
/* execute the next instruction ... */
}
}
By default the check interval is 1000 bytecodes. All threads run this same code and have the lock taken from them periodically in the same way. In Python 3 the GIL's implementation is more complex, and the check interval is not a fixed number of bytecodes, but 15 milliseconds. For your code, however, these differences are not significant.
Thread safety in Python
Weaving together multiple threads requires skill.
If a thread can lose the GIL at any moment, you must make your code thread-safe. Python programmers think differently about thread safety than C or Java programmers do, however, because many Python operations are atomic.
An example of an atomic operation is calling sort() on a list. A thread cannot be interrupted in the middle of sorting, and other threads never see a partly sorted list, nor see stale data from before the list was sorted. Atomic operations simplify our lives, but there are surprises. For example, += seems simpler than sort(), but += is not atomic. How can you know which operations are atomic and which are not?
Consider this code:
n = 0
def foo():
global n
n += 1
We can see the bytecode to which this function compiles, with Python's standard dis module:
>>> import dis
>>> dis.dis(foo)
LOAD_GLOBAL 0 (n)
LOAD_CONST 1 (1)
INPLACE_ADD
STORE_GLOBAL 0 (n)
One line of code, n += 1, has been compiled to four bytecodes, which do four primitive operations:
- load the value of n onto the stack
- load the constant 1 onto the stack
- sum the two values at the top of the stack
- store the sum back into n
Remember that every 1000 bytecodes a thread is interrupted by the interpreter taking the GIL away. If the thread is unlucky, this might happen between the time it loads the value of n onto the stack and when it stores it back. How this leads to lost updates is easy see:
threads = []
for i in range(100):
t = threading.Thread(target=foo)
threads.append(t)
for t in threads:
t.start()
for t in threads:
t.join()
print(n)
Usually this code prints 100, because each of the 100 threads has incremented n. But sometimes you see 99 or 98, if one of the threads' updates was overwritten by another.
So, despite the GIL, you still need locks to protect shared mutable state:
n = 0
lock = threading.Lock()
def foo():
global n
with lock:
n += 1
What if we were using an atomic operation like sort() instead?:
lst = [4, 1, 3, 2]
def foo():
lst.sort()
This function's bytecode shows that sort() cannot be interrupted, because it is atomic:
>>> dis.dis(foo)
LOAD_GLOBAL 0 (lst)
LOAD_ATTR 1 (sort)
CALL_FUNCTION 0
The one line compiles to three bytecodes:
- load the value of lst onto the stack
- load its sort method onto the stack
- call the sort method
Even though the line lst.sort() takes several steps, the sort call itself is a single bytecode, and thus there is no opportunity for the thread to have the GIL seized from it during the call. We could conclude that we don't need to lock around sort(). Or, to avoid worrying about which operations are atomic, follow a simple rule: Always lock around reads and writes of shared mutable state. After all, acquiring a threading.Lock in Python is cheap.
Although the GIL does not excuse us from the need for locks, it does mean there is no need for fine-grained locking. In a free-threaded language like Java, programmers make an effort to lock shared data for the shortest time possible, to reduce thread contention and allow maximum parallelism. Because threads cannot run Python in parallel, however, there's no advantage to fine-grained locking. So long as no thread holds a lock while it sleeps, does I/O, or some other GIL-dropping operation, you should use the coarsest, simplest locks possible. Other threads couldn't have run in parallel anyway.
Finishing sooner with concurrency
I wager what you really came for is to optimize your programs with multi-threading. If your task will finish sooner by awaiting many network operations at once, then multiple threads help, even though only one of them can execute Python at a time. This is concurrency, and threads work nicely in this scenario.
This code runs faster with threads:
import threading
import requests
urls = [...]
def worker():
while True:
try:
url = urls.pop()
except IndexError:
break # Done.
requests.get(url)
for _ in range(10):
t = threading.Thread(target=worker)
t.start()
As we saw above, these threads drop the GIL while waiting for each socket operation involved in fetching a URL over HTTP, so they finish the work sooner than a single thread could.
Parallelism
What if your task will finish sooner only by running Python code simultaneously? This kind of scaling is called parallelism, and the GIL prohibits it. You must use multiple processes, which can be more complicated than threading and requires more memory, but it will take advantage of multiple CPUs.
This example finishes sooner by forking 10 processes than it could with only one, because the processes run in parallel on several cores. But it wouldn't run faster with 10 threads than with one, because only one thread can execute Python at a time:
import os
import sys
nums =[1 for _ in range(1000000)]
chunk_size = len(nums) // 10
readers = []
while nums:
chunk, nums = nums[:chunk_size], nums[chunk_size:]
reader, writer = os.pipe()
if os.fork():
readers.append(reader) # Parent.
else:
subtotal = 0
for i in chunk: # Intentionally slow code.
subtotal += i
print('subtotal %d' % subtotal)
os.write(writer, str(subtotal).encode())
sys.exit(0)
# Parent.
total = 0
for reader in readers:
subtotal = int(os.read(reader, 1000).decode())
total += subtotal
print("Total: %d" % total)
Because each forked process has a separate GIL, this program can parcel the work out and run multiple computations at once.
(Jython and IronPython provide single-process parallelism, but they are far from full CPython compatibility. PyPy with Software Transactional Memory may some day be fast. Try these interpreters if you're curious.)
Conclusion
Now that you've opened the music box and seen the simple mechanism, you know all you need to write fast, thread-safe Python. Use threads for concurrent I/O, and processes for parallel computation. The principle is plain enough that you might not even need to write it on your hand.
A. Jesse Jiryu Davis will be speaking at PyCon 2017, which will be held May 17-25 in Portland, Oregon. Catch his talk, Grok the GIL: Write Fast and Thread-Safe Python, on Friday, May 19.
15 Comments
Hi Jesse, This is the greatest article I've read about GIL and Multithread programming in Python. Thanks a lot ;)
Good article, but there are a couple of issues with it. (a) Extension modules can also release the GIL during purely CPU operations. Most notably, numpy does this if you perform operations on large matrices, like dot, +, or even sort! . If you're doing something computationally intensive you ought to be using something like this anyway, because the core code is written in C and will run orders of magnitude faster than a hand-rolled loop written in Python. This is the main misconception about the GIL and it's a shame that this article propagates it. (b) Although you mentioned that you're only writing about CPython, I don't think you made it clear that the stuff about individual operations being atomic (like sort) only applies to CPython. Besides, what is one op code in today's version of Python might be multiple in a later version. So your discussion using dis is academically interesting but you really should manually lock in cases like that.
Nice article and very helpful how you included CPython code for background.
I think, though, that your statement about list.sort() being atomic is not accurate. In a preempt-able scenario with multiple threads, there's nothing preventing thread 1 from starting to sort the list in-place, runs out of the 1000 bytecodes or 15ms that's allocated to it, and then another thread becomes the currently running thread and appends an item to it. This would be a problem. An external locking mechanism is needed to guarantee the list.sort() function is not interrupted.
From the documentation:
."
Thanks Nate. Check out the bytecode: list.sort() is a single bytecode, so it cannot be interrupted. The documentation you refer to describes how a C extension must interact with a list, while it is being sorted, if the C extension is running a thread that does not hold the GIL. Your Python code always holds the GIL while it runs, and therefore it can never see a list *while* it is being sorted by another thread.
Thanks for clarifying. This makes sense as long as the GIL will not be relinquished in the CPython code, which from your other examples seems to only be done consciously by IO-dependent code, which I take from what you've written to be the case.
`list.sort()` is uninterruptible if it contains numbers. But if it contains arbitrary python objects, which may have their own arbitrary `__cmp__` methods, sort *can* be interrupted.
Similarly, objects with custom `__hash__` methods can make single-bytecode operations become interruptible in ways that are sometimes surprising. Disassembly is not a reliable indicator of things that are made atomic by the GIL; it takes a deeper knowledge of what exactly those bytecodes are doing.
Thanks Ben, that's definitely correct! I thought of that recently and I've updated the text on my personal site.
Is .pop() method thread-safe? (atomic?)
i.e., can it be safely applied to a shared list (urls) ?
Yes, with the same caveats as Ben Darnell pointed out in the comments here.
Hi Jesse, thanks for your great article. Though the website labeling CC-BY-SA, I want to ask you, could I translate your article to traditional Chinese and share on my blog? (), thanks!
Also, you're using 2.7 as the example, would you plan for using 3.x for example in the future?
Hi Louie, yes, please do translate it!
I chose 2.7 because its implementation of the GIL is simpler and easier to understand the Python 3's. I have no plan to change the example.
in the locking section you make the statement: "So long as no thread holds a lock while it sleeps, does I/O, or some other GIL-dropping operation, you should use the coarsest, simplest locks possible. Other threads couldn't have run in parallel anyway."
What prevents the preemptive dropping of the GIL from happening while you have a lock?
Hi! Nothing prevents a thread from preemptively dropping the GIL while it holds a lock. Let's call that Thread A, and let's say there's also a Thread B. If Thread A holds a lock and gets preempted, then maybe Thread B could run instead of Thread A.
If Thread B is waiting for the lock that Thread A is holding, then Thread B is *not* waiting for the GIL. In that case Thread A reacquires the GIL immediately after dropping it, and Thread A continues.
If Thread B is not waiting for the lock that Thread A is holding, then Thread B might acquire the GIL and run.
My point about coarse locks, however, is this: no two threads can ever execute Python in parallel, because of the GIL. So using fine-grained locks doesn't improve throughput. This is in contrast to a language like Java or C, where fine-grained locks allow greater parallelism, and therefore greater throughput.
Thanks for your quick response!
If I'm understanding you correctly, the intent of the statement I referenced was to avoid using locks around external operations, where you could then block multiple threads, if they all depended on that lock.
For the preemptive example, Thread A isn't blocked by anything externally, so the processing just goes back and forth similar to cooperative multitasking.
Do I have that right?
Yes, that sounds right! | https://opensource.com/article/17/4/grok-gil?hmsr=pycourses.com&utm_source=pycourses.com&utm_medium=pycourses.com | CC-MAIN-2019-35 | refinedweb | 3,124 | 62.38 |
table of contents
NAME¶
DPCURV - Used to draw a complete curve defined by a sequence of points in the user coordinate system.
SYNOPSIS¶
CALL DPCURV (XCPU,YCPU,NPTS)
C-BINDING SYNOPSIS¶
#include <ncarg/ncargC.h>
void c_dpcurv (float *xcpu, float *ycpu, int npts);
DESCRIPTION¶
- XCPU
- (an input array of type REAL) specifies the X coordinates of points in the user coordinate system defining a curve to be drawn.
- YCPU
- (an input array of type REAL) specifies the Y coordinates of points in the user coordinate system defining a curve to be drawn.
- NPTS
- (an input expression of type INTEGER) specifies the number of points defining the curve.
C-BINDING DESCRIPTION¶
The C-binding argument descriptions are the same as the FORTRAN argument descriptions.
USAGE¶
The FORTRAN statement .
EXAMPLES¶
Use the ncargex command to see the following relevant examples: tdshpk.
ACCESS¶
To use DPCURV or c_dpcurv, load the NCAR Graphics libraries ncarg, ncarg_gks, and ncarg_c, preferably in that order.
SEE ALSO¶
Online: dashpack, dashpack_params, dpdraw, dpfrst, dpgetc, dpgeti, dpgetr, dplast, dpline, dpsetc, dpseti, dpsetr, dpsmth, dpvect, ncarg_cbind.
Hardcopy: None.
University Corporation for Atmospheric Research
The use of this Software is governed by a License Agreement. | https://manpages.debian.org/unstable/libncarg-dev/dpcurv.3ncarg.en.html | CC-MAIN-2022-40 | refinedweb | 194 | 54.22 |
Probably all of us tried to write a code to scramble text so that we could pass secret messages around. C# has encrypting ability built in but it's not fun to use something that is already there. I had some extra(!) time last couple of days, so I wrote my own text scrambler.
This program gets you a different output each time... it is very difficult to crack. You have to know where to look, I don't think anyone who doesn't know the code could find the encrypted text in the scrambled version, but who knows... Some of us are very smart.
This program has two sections of scrambling. In the first section, it transfers text into binary code. I was able to use bitArray, but I couldn't find a simple way to reverse it, so I added "character" and "binary" lists instead. The scrambler is a class, so I think it should work as fast as a normal encryptor. The second section of the scrambler is actually doing the heavy work. It does enter random characters and random amount between each binary number. Every time the binary replacements and the amount of the characters between them are random, so that no one would actually know which character set is to be replaced with the binary numbers (1 and 0s).
bitArray
(Article format: Explanations followed by their code.)
Form1. Class calls from the button event handlers.
{
public partial class Form1 : Form{
Scrambler.Scrambler NewScr = new Scrambler.Scrambler();
public Form1(){
InitializeComponent();}
private void button2_Click(object sender, EventArgs e){
MessageBox.Show(NewScr.MainString(textBox2.Text ,0));}
private void button3_Click(object sender, EventArgs e){
MessageBox.Show(NewScr.MainString(textBox3.Text, 1));}
private void button1_Click(object sender, EventArgs e){
textBox2.Text = NewScr.BinaryString(textBox1.Text);
textBox3.Text = NewScr.ScrambledString(textBox1.Text);}
private void button4_Click(object sender, EventArgs e){
// Exit the program
if (Application.MessageLoop){
// Use this since we are a WinForms app
Application.Exit();}
else{
// Use this since we are a console app
Environment.Exit(1);}}}
}
In the Class module...
private string AllScrChrs: The scrambler characters. You can always change the amount of the characters to make your code more complicated or less complicated.
private string AllScrChrs
private string AllScrChrs =
"!@#$%&*abcdefghiklmnopqrstuvwxyzABCDEFGHIKLMNOPQRSTUVWXYZ1234567890";
There are three public methods in the class:
public
public string BinaryString(string MainString)
Passes the text from the textbox and returns binary string
public string ScrambledString(string MainString)
Passes the text from the textbox and returns scrambled string
public string MainString(string PassingStr, byte BinaryOrScrambled)
Passes the Binary or scrambled string, and a Boolean value to determine which one will be processed. Either Binary to Text, or Scrambled to text. If selected from scrambled, code first transfers the string to binary string, and then decodes to text.
public string BinaryString(string MainString){
return BinaryWork(MainString);}
public string ScrambledString(string MainString){
return ScrambstrBinaryext(BinaryWork(MainString));}
public string MainString(string PassingStr, byte BinaryOrScrambled){
string MainText = "";
switch (BinaryOrScrambled){
case 0:
MainText = DecodeBinary(PassingStr);
break;
case 1:
MainText = DecodeBinary((UnScrambstrBinaryext(PassingStr)));
break;}
return MainText;}
private string BinaryWork(string WhatToWorkOn)
This method is called to create binary code of the text entered.
private string BinaryWork(string WhatToWorkOn){
string BinaryResults = "";
foreach (char GetChr in WhatToWorkOn){
BinaryResults += GetBinary(GetChr);}
return BinaryResults;}
private string GetBinary(char strChr){
return Convert.ToString(strChr, 2).PadLeft(8, '0');}
private string DecodeBinary(string PassingString)
From this method, characters are created from the binary string.
private string DecodeBinary(string PassingString){
int ii;
string CharResult="";
for (ii = 0; ii < PassingString.Length; ii+=8){
try{
CharResult += GetCharacter(PassingString.Substring(ii, 8));}
catch (OverflowException) { }}
return CharResult;}
private char GetCharacter(string strBinary){
return (char)Convert.ToInt32(strBinary, 2);}
private string ScrambstrBinaryext(string ScrString)
The main scrambler. Let me just explain what this portion of the code does instead of a line-by-line tutorial.
private string OneAndZero(int Rept, string sOZ)
I used this method to enter random character with random amount of 3 to between the binary numbers. This method is also called before binary numbers start and after binary numbers end. So, not only between binary numbers and binary numbers itself, also two ends are randomly scrambled to make things more complicated.
private string ScrambstrBinaryext(string ScrString){
int rndRep;
Random intRan = new Random();
string newString = "";
string ScrChrs = AllScrChrs;
string chrOne = ScrChrs.Substring(intRan.Next(ScrChrs.Length), 1);
ScrChrs = ScrChrs.Replace(chrOne, "");
string chrZero = ScrChrs.Substring(intRan.Next(ScrChrs.Length), 1);
ScrChrs = ScrChrs.Replace(chrZero, "");
int IntStrLength = ScrString.Length;
foreach (char OZchr in ScrString){
rndRep = intRan.Next(3);
switch (OZchr){
case '1': // I wrote a method to make things simpler.
newString += OneAndZero(rndRep, chrOne) + OneAndZero(rndRep, ";");
break;
case '0':
newString += OneAndZero(rndRep, chrZero) + OneAndZero(rndRep, ":");
break;}
newString += OneAndZero(intRan.Next(1, 3),
ScrChrs.Substring(intRan.Next(ScrChrs.Length), 1));}
// When returned, the first and the last character are
// random to confuse people. Before that, two characters are our guys
return OneAndZero(intRan.Next(1, 3),
ScrChrs.Substring(intRan.Next(ScrChrs.Length), 1))
+ newString + OneAndZero(intRan.Next(3), chrOne) +
OneAndZero(intRan.Next(3), chrZero)
+ OneAndZero(intRan.Next(1, 3),
ScrChrs.Substring(intRan.Next(ScrChrs.Length), 1));}
// This method is called a few times to enter random number of characters
private string OneAndZero(int Rept, string sOZ){
int ii;
for (ii = 0; ii < Rept; ii++){
sOZ += sOZ.Substring(0, 1);}
return sOZ;}
private string UnScrambstrBinaryext(string Uscr)
Descrambler. Once again, instead of going the code line by line, let me explain what this portion of the code is doing.
private string rvsString(string ReverseThis)
The most, last 9 characters of the code contain 1-extra character at the end, 2-Binary "1" 3-Binary "0" characters that we will need to replace. A very important portion of the code is finding out which characters are "1" and "0" that sit in last three characters of the scrambled text. This way, we can put any character for them each scramble calls.
private string SingleString(string MultiString, string StrFull)
All the duplicated characters will be singled.
private string UnScrambstrBinaryext(string Uscr){
// Cut last 9 characters of the text
// Last 9 characters contain the extra character with 1 & 0 characters
string[] strOneToZero = new string[3];
string ScrChrs = AllScrChrs;
int ii;
string LastNine = rvsString(Uscr.Substring(Uscr.Length - 9));
// A unique way to find unique characters once ;)
foreach (char ChrNine in LastNine){
if (strOneToZero[0] == null){
strOneToZero[0] = ChrNine.ToString(); continue;}
if (strOneToZero[0] == ChrNine.ToString()) continue;
if (strOneToZero[1] == null){
strOneToZero[1] = ChrNine.ToString(); continue;}
if (strOneToZero[1] == ChrNine.ToString()) continue;
strOneToZero[2] = ChrNine.ToString();
break;}
// We need array "1" and "2". "0" is extra
ScrChrs = ScrChrs.Replace(strOneToZero[1],"");
ScrChrs = ScrChrs.Replace(strOneToZero[2], "");
for (ii = 0; ii < ScrChrs.Length; ii++){
Uscr = Uscr.Replace(ScrChrs.Substring(ii,1),"");}
// I wrote a method to make things simpler.
Uscr = SingleString(strOneToZero[1], Uscr);
Uscr = SingleString(strOneToZero[2], Uscr);
Uscr = Uscr.Replace(";", "");
Uscr = Uscr.Replace(":", "");
Uscr = Uscr.Replace(strOneToZero[1], "0");
Uscr = Uscr.Replace(strOneToZero[2], "1");
return Uscr.Substring(0,(Uscr.Length-2));} // Last two was our guys remember?
// Replace duplicate characters with single
private string SingleString(string MultiString, string StrFull){
while (StrFull.IndexOf(MultiString + MultiString) != -1){
StrFull = StrFull.Replace(MultiString + MultiString, MultiString);}
return StrFull;}
// I wrote this reverser for the last 9 characters of the scrambled text
private string rvsString(string ReverseThis){
string rvSt = "";
int ii;
for (ii = (ReverseThis.Length-1); ii > 0; ii--){
rvSt += ReverseThis.Substring(ii, 1);}
return rvSt;}
This is a very simple code, with simple text and character work. It was a study/practice code which I found interesting enough to publish. I hope you find it interesting. | http://www.codeproject.com/Articles/79113/Scrambler?fid=1570953&df=90&mpp=10&sort=Position&spc=None&tid=3474771 | CC-MAIN-2016-18 | refinedweb | 1,253 | 51.14 |
On Sun, Jan 23, 2005 at 05:47:41PM +1100, Graham Dumpleton wrote:
> Since configuration in file as opposed to .htaccess, I assume
> that Apache was restarted?
Yes, I've restarted apache many times, using 'apachectl stop && apachectl
start'. I've also removed the .htaccess that comes with psp_site so that's
not in the picture.
> After restarting Apache, when you try and access the file which you
> expect
> to be managed by the mod_python.publisher handler, do you see a line
> appear
> in the Apache error log file of the form?
(Read your post about the mailing list archives, and found that the problem
wasn't google not indexing it, but that I had searched for 'psp psp_site
publisher' which appearantly has no results. Mea culpa.)
I do not see that in the error log. In fact, I don't see anything in the
error log, unless I try going to any of the following combinations:
And then it's just a file not found error.
In reading through the archives on anything that seemed to relate to my
problem, I switched from SetHandler to:
AddHandler python-program .py
And now mod_python seems to be parsing pages, but not really how I'd like.
If I goto index/index, I get a cannot import psp error, but at least
mod_python works now. So I throw up a hello.py:
def index():
return 'Hello there!'
68.186.66.XXX - - [23/Jan/2005:07:15:47 +0000] "GET /hello.py HTTP/1.1" 404 334 "-" "Mozilla/5.0 (Macintosh; U; PPC Mac OS X; en-US) AppleWebKit/125.4 (KHTML, like Gecko, Safari) OmniWeb/v563.34"
Notice the 404 error, but nothing in error_log.
[Sun Jan 23 07:17:23 2005] [notice] mod_python: (Re)importing hello from ['/var/www/rvmotel-beta']
So, I have it most of the way there to being able to develop. But I can't
seem to get publisher to run the index() function like all the docs I've come
across say I can. I also can not get it to treat index.py as the directory
index. This means I need to use something like an index.html with a meta
refresh, which I'd like to avoid if at all possible.
So, some progress, but ever more questions. Why does AddHandler work, but
the SetHandler that the docs say to use doesn't? Why can't I get it to
process index.py or the index() function?
Thanks for your help.
-Zach | https://modpython.org/pipermail/mod_python/2005-January/017190.html | CC-MAIN-2022-21 | refinedweb | 418 | 76.22 |
Timeline
04/26/2008:
- 22:27 Changeset [32603] by
-
- 22:27 Changeset [32602] by
-
- 20:10 Changeset [32601] by
Delete the DerivedSources after make clean has been done so that the DerivedSouces don't get re-created. Also, use the proper extension for the Win wxPython extension.
- 19:24 Changeset [32599] by
Versioning.
- 19:23 Changeset [32598] by
New tag.
- 18:56 Changeset [32597] by
Another round of build fixes, hopefully the last this time.
- 17:35 Changeset [32595] by
Reviewed by Kevin Ollivier.
Allow the user to set the path to SWIG using an environment variable.
- 17:28 Changeset [32594] by
wx build fix. Add needed wx includes for compilation.
- 17:21 Changeset [32593] by
wx build fix. Download the latest libpng version for building the dependencies.
- 13:12 Changeset [32592]
Fix the changelog
04/25/2008:
- 20:28 Changeset [32588] by
<rdar://problem/5891264> Don't install the JavaScriptGlue headers
Reviewed by Adele Peterson.
- 19:02 Changeset [32587] by
Add some content to an empty ICU header file to prevent verification errors.
Rubber-stamped by Sam Weinig.
- 16:38 Changeset [32582] by
2008-04-25 Anders Carlsson <andersca@apple.com>
Fix tyop.
- loader/DocumentLoader.cpp: (WebCore::DocumentLoader::scheduleApplicationCacheLoad):
- 16:36 Changeset [32581] by
2008-04-25 Mark Rowe <mrowe@apple.com>
Upgrade to WordPress 2.5.1. Another day, another security vulnerability in WordPress.
- 15:41 Changeset [32579]
2008-04-25 Anders Carlsson <andersca@apple.com>
Reviewed by Adam.
Fix internal debug build.
- WebKit.vcproj/WebKit.vcproj:
- 11:11 Changeset [32575] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Respect antialiasing hint when drawing focus rects.
- 05:37 Changeset [32571] by
Kavindra Devi Palaraja <kdpalara@trolltech.com>
completed documentation for the Detailed Description section for QWebView
- 05:37 Changeset [32570] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Fix resubmit of HTML forms when initially denied by QWebPage::acceptNavigationRequest().
- 03:49 Changeset [32568] by
Ariya Hidayat <ariya.hidayat@trolltech.com>
Fix triple-clicking does not work in a web page
- 03:49 Changeset [32566] by
Benjamin Meyer <bmeyer@trolltech.com>
When pressing Ctrl-Up the keyboard modifiers could include other modifiers
- 03:48 Changeset [32564] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Fix handling of Javascript's confirm() function in QtWebKit.
- 03:41 Changeset [32563] by
Kavindra Devi Palaraja <kdpalara@trolltech.com>
Doc - added a screenshot, flowchart, and a snippet to the QWebView documentation to improve clarity
- 03:32 Changeset [32562] by
Benjamin Meyer <bmeyer@trolltech.com>
QWebPage: missing signal when window.print() is requested from javascript
- 03:32 Changeset [32561] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Fix propagation of mouse double click events.
Treat a mouse double click as a regular mouse press with just a different click count.
- 03:32 Changeset [32560] by
Benjamin Meyer <bmeyer@trolltech.com>
Fixes: "Save Image" action wasn't doing anything.
- 03:31 Changeset [32559] by
Benjamin Meyer <bmeyer@trolltech.com>
Apply key event changes to the current frame, not the main frame.
Example: hitting space bar should scroll current frame, not the main frame
which doesn't even have a scrollbar.
- 03:00 Changeset [32557] by
Benjamin Meyer <bmeyer@trolltech.com>
Fixes: QWebFrame crash when fetching the icon
Just call QWebSettings::iconForUrl to not duplicate code and obey the mutex lock.
- 02:59 Changeset [32556] by
Benjamin Meyer <bmeyer@trolltech.com>
Fixes: Valgrind warnings about uninitilized variables used in jumps
- 02:59 Changeset [32555] by
Warwick Allison <warwick@trolltech.com>
Fixes: Scrollbars did not report correct maximum.
- 02:59 Changeset [32554] by
Benjamin Meyer <bmeyer@trolltech.com>
Implement NoDrop, ZoomIn, and ZoomOut cursors
- 02:01 Changeset [32553] by
Holger Hans Peter Freyther <zecke@selfish.org>
Correct the comment. We are in painTextField and don't paint a button.
- 02:00 Changeset [32550] by
Holger Hans Peter Freyther <zecke@selfish.org>
Allow ListboxAppearance to take focus as well. Stolen from Tor Arne
- 02:00 Changeset [32549] by
Holger Hans Peter Freyther <zecke@selfish.org>
Do not execute most of the http tests as they hang or crash.
- 02:00 Changeset [32548] by
Simon Hausmann <hausmann@webkit.org>
Remove debug output.
- 01:28 Changeset [32547] by
Bug 18736: SQUIRRELFISH: switch statements with no default have incorrect codegen
<>
Reviewed by Maciej
Ensure the "default" target is correct in the absence of an explicit default handler.
- 01:10 Changeset [32546] by
David Boddie <dboddie@trolltech.com>
Documentation updates for some of the QWeb classes
- 01:09 Changeset [32545] by
Fixing the ChangeLog
- 01:08 Changeset [32544] by
Bug 18732: SQUIRRELFISH: exceptions thrown by native constructors are ignored
<>
Reviewed by Maciej
More bounds checking.
- 00:53 Changeset [32543] by
Holger Hans Peter Freyther <zecke@selfish.org>
Change the string to match the mac and pass http/tests/misc/isindex-formdata.html
- 00:52 Changeset [32541] by
Simon Hausmann <hausmann@webkit.org>
When we encounter a new/unknown HTTP request type report it back to WebCore as loading error.
- 00:51 Changeset [32540]
Benjamin Meyer <bmeyer@trolltech.com>
Fix crash in the networking layer.
Set the m_reply to null right after calling deleteLater().
- 00:27 Changeset [32538]/2008:
- 23:45 Changeset [32536]
2008-04-24 Geoffrey Garen <ggaren@apple.com>
Reviewed by Oliver Hunt.
Added support for arguments.callee.
- 23:42 Changeset [32534] by
2008-04-24 Mark Rowe <mrowe@apple.com>
Rubber-stamped by Oliver Hunt.
- WebCore.base.exp: Remove two symbols from the export list that don't need to be exported.
- 22:00 Changeset [32533] by
Add a definition of BUILDING_ON_LEOPARD to complement BUILDING_ON_TIGER.
Reviewed by Sam Weinig.
- 17:58 Changeset [32528] by
2008-04-24 Jan Michael Alonzo <jmalonzo@unpluggable.com>
Reviewed by Maciej Stachowiak.
Typo and documentation fix for build-webkit
- Scripts/build-webkit:
- 17:47 Changeset [32526] by
WebKit/gtk:
- build fix
- webkit/webkitwebview.cpp:
WebKit/win:
- build fix
- WebView.cpp: (WebView::handleContextMenuEvent):
- 16:18 Changeset [32522] by
Fixed up ChangeLog
- 16:18 Changeset [32521]
2008-04-24 Anders Carlsson <andersca@apple.com>
Windows build fix.
- html/HTMLFormElement.cpp: (WebCore::pathGetFilename):
- 12:43 Changeset [32516] by
Add svg mask example.
- 12:42 Changeset [32515] by
Add svg file of a circle.
- 12:26 Changeset [32514] by
Add more files.
- 12:21 Changeset [32513] by
Add kate gradient pic.
- 12:16 Changeset [32512] by
2008-04-24 Anders Carlsson <andersca@apple.com>
Reviewed by Sam.
Don't call fprintf from the signal handler.
- DumpRenderTree/mac/DumpRenderTree.mm: (crashHandler):
- 12:16 Changeset [32511] by
Adjust files.
- 12:15 Changeset [32510] by
2008-04-24 Anders Carlsson <andersca@apple.com>
Don't crash when the string is empty.
- html/HTMLMediaElement.cpp: (WebCore::parseTimeOffset):
- 12:12 Changeset [32509] by
Add more files.
- 12:09 Changeset [32508] by
Check in kate image for blog post.
- 12:00 Changeset [32506] by
Add blog files for mask post.
- 11:57 Changeset [32505] by
..
2008-04-24 Sam Weinig <sam@webkit.org>
Fix the world.
- bindings/js/kjs_proxy.cpp: (WebCore::KJSProxy::clear):
- 11:51 Changeset [32503] by
Add blog images.
- 11:45 Changeset [32502] by
Holger Hans Peter Freyther <zecke@selfish.org>
Cosmetic changes to make the code more readable.
-Early exit if we don't have a webview
-handle the empty tooltip and non-empty tooltip case separately
- 07:07 Changeset [32488] by
Fix text rendering in -reverse mode on Qt/Mac.
For Font::width() don't use a plain QFontMetrics object but also the properly
setup QTextLayout that has the RTL/LTR force flags set.
- 07:06 Changeset [32487] by
Paul Olav Tvete <paul@trolltech.com>
Fix various compiler warnings related to QString(const char *)
construction by using QLatin1String.
- 06:44 Changeset [32485] by
Holger Hans Peter Freyther <zecke@selfish.org>
Allow to disable caching completeley by calling setObjectCacheCapacities(0, 0, 0)
- 04:20 Changeset [32482] by
Fix the Gtk and Qt builds.
Added missing localization stubs for accessibility.
- 03:35 Changeset [32480] by
Benjamin Meyer <bmeyer@trolltech.com>
Improve keyboard scrolling
Match Down/Up keys scroll distance with Safari (i.e. faster) and add Home and End shortcuts to scroll to the top/botom.
- 03:20 Changeset [32479] by
Olivier Goffart <ogoffart@trolltech.com>
Fix various compiler warnings in the Qt port.
- 03:20 Changeset [32478] by
Andre Poenitz <andre.poenitz@trolltech.com>
Removed spurious QHideEvent forward declaration.
- 02:01 Changeset [32477] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Render text areas using Qt (ensures proper style).
- 01:53 Changeset [32475] by
2008-04-23 Jon Honeycutt <jhoneycutt@apple.com>
Reviewed by Adam.
Implement accLocation().
- AccessibleBase.cpp: (AccessibleBase::accLocation): Report the screen coordinates for the object's bounding box.
- 01:21 Changeset [32468] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Cleaned up copyright headers in the Qt port (removed misplaced class
descriptions and fixed inconsistent whitespace and indentation).
- 00:44 Changeset [32463] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Added basic URL guessing to QtLauncher (same as in the demo browser).
- 00:44 Changeset [32462] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Disable vanlilla focus rings since Qt provides this as part of the style.
- 00:38 Changeset [32461] by
George Staikos <george@staikos.net>
This optimization in BitmapImage::drawPattern for the identity
transform is bogus and causes incorrect results on sites like youtube.
- 00:31 Changeset [32460] by
Benjamin Meyer <bmeyer@trolltech.com>
Prevent double deletions of the default web interface.
04/23/2008:
- 22:27 Changeset [32459]
Reviewed by Alp Toker.
Typo fix to restore text entry.
- 20:39 Changeset [32454] by
wx build fixes. Changing BackgroundLayer -> FillLayer and adding Frame::disconnectPlatformScriptObjects()
- 14:00 Changeset [32447]
2008-04-23 Darin Adler <darin@apple.com>
- updated a test affected by the addition of mask-composite
- svg/css/getComputedStyle-basic-expected.txt: Updated.
- 07:50 Changeset [32438] by
Fix compilation against Qt 4.3
- 07:44 Changeset [32436]
Brad Hughes <bhughes@trolltech.com>
Fix release build with the intel compiler
Intel compiler can't compile qtwebkit with -O2 or -O1, so we're left with -O0
- 07:36 Changeset [32433] by
Holger Hans Peter Freyther <zecke@selfish.org>
Removed the #define for USE_SYSTEM_MALLOC that we set in WebKit.pri
already.
- 01:31 Changeset [32430] by
Benjamin Meyer <bmeyer@trolltech.com>
Fixes background color propagation when using a custom QWebPage
Set the palette in setPage(), not during the creation on-demand.
- 01:26 Changeset [32429] by
Benjamin Meyer <bmeyer@trolltech.com>
Fix the user agent on the mac to be BSD4
Put Q_OS_DARWIN before Q_OS_BSD4 sense they are both defined on the mac
- 01:07 Changeset [32428] by
Added missing copyright notice.
Small fixes to the documentation.
- 00:49 Changeset [32427] by
Zack Rusin <zack@tungstengraphics.com>
Added a contentsSize() property.
04/22/2008:
- 21:22 Changeset [32426] by
Reviewed by Anders Carlsson.
- remove unused calls to Position::upstream()
- editing/InsertLineBreakCommand.cpp: (WebCore::InsertLineBreakCommand::insertNodeAfterPosition): (WebCore::InsertLineBreakCommand::insertNodeBeforePosition):
- 21:19 Changeset [32425] by
2008-04-22 Alp Toker <alp@nuanti.com>
GTK+ debug build fix for changes in r32257.
- GNUmakefile.am:
- 20:13 Changeset [32419]
Add new layout test results.
- 17:13 Changeset [32413] by
2008-04-22 Antti Koivisto <antti@apple.com>
Update SVG animation test results.
- platform/mac/svg/W3C-SVG-1.1/animate-elem-33-t-expected.txt:
- 16:51 Changeset [32411] by
2008-04-22 Maciej Stachowiak <mjs@apple.com>
Reviewed by Geoff.
- kjs/testkjs.cpp: (main): Convert signals to exit codes, so that crashing tests are detected as regression test failures.
- 14:49 Changeset [32408] by
Bug 18683: update-webkit returns 0 even if it fails
<>
Reviewed by Mitz Pettel.
- Scripts/update-webkit: (runSvnUpdate): Die if close() fails.
- 14:40 Changeset [32406] by
Fix typo in ChangeLog.
- 13:42 Changeset [32402] by
Fixed ChangeLog
- 10:55 Changeset [32398]
Qt build fix.
Adjust the Qt resource file to removed image files.
- 06:56 Changeset [32393] by
Andre Poenitz <andre.poenitz@trolltech.com>
Remove compiler warnings on string literals used to construct QStrings
in webkit.
- 04:33 Changeset [32391] by
Benjamin Meyer <bmeyer@trolltech.com>
Fixes: QWebPage's QNetworkManager's can be shared among webpages.
Don't force the deletion of the object, but let QObject take care of it.
- 04:27 Changeset [32390] by
Documentation for QWebPluginFactory and documentation updates for QWebPage.
- 04:27 Changeset [32389] by
Simon Hausmann <hausmann@webkit.org>
Added QWebPage::swallowContextMenuEvent and QWebPage::updatePositionDependentActions.
- 03:56 Changeset [32388] by
Added Extension APIs for QWebPage.
- 03:46 Changeset [32387] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Emit loadProgress() signal on loadStarted().
- 03:33 Changeset [32386] by
Zack Rusin <zack@kde.org>
Fix background propagation from the QWebView's palette.
The background brush of the palette needs to be propagated to the WebCore::FrameView.
- 03:30 Changeset [32385] by
Benjamin Meyer <bmeyer@trolltech.com>
Fix maps.google.com
We have to include a version in the Safari tag in the user-agent.
- 03:30 Changeset [32384] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Fall back to last path component for suggested filename if the HTTP content disposition is not set.
- 03:14 Changeset [32383]
Tor Arne Vestbø <tavestbo@trolltech.com>
Implemented the generation of the title string for images.
- 02:31 Changeset [32381] by
Tor Arne Vestbø <tavestbo@trolltech.com>
Add visual focusing hint for clear button and
Change focus to web page after user enters new URL.
- 01:31 Changeset [32380] by
Added QWebFrame::hitTestContent() and QWebHitTestResult.
- 01:31 Changeset [32379] by
Simon Hausmann <hausmann@webkit.org>
Don't crash if an input method query is done without a page.
- 01:30 Changeset [32378] by
Thiago Macieira <tjmaciei@trolltech.com>
Fixes: Pedantic compilation fix
Don't put semi-colons after braces closing namespaces.
- 00:43 Changeset [32374] by
Qt build fix. | http://trac.webkit.org/timeline?from=2008-04-26T18%3A56%3A37-0700&precision=second | CC-MAIN-2014-10 | refinedweb | 2,251 | 53.17 |
Module Development - Packaging Martin Hejtmanek — Dec 21, 2015 modulescustomizationnugetkentico 9 Packaging your module is an important part of the module life cycle. Read this article to learn more about the new module packaging options which are available in Kentico 9. Hi there, I intentionally postponed my Module development article series for a while, because I was waiting for Kentico 9 to be released with new related features. Just in case you are new to module development in Kentico, here is the whole list of my articles about this topic: Introduction Foreign keys Parent-child relationships Bindings UI Extenders Order and priorities Versioning and recycle bin And here is a link to the official documentation for the latest version: The next important topic I would like to cover is module packaging and deployment. In version 8, you had to use export packages to deploy a module to other instances and it was kind of limiting. In 8.2 we added support for basic packaging to NuGet, but you had to combine it with manual importing of the module’s data using export packages. Kentico 9 solves this by merging the export package and other related module aspects to the module NuGet package. All this data and code can be installed automatically, just as developers are used to when using NuGet packages. You can read about the whole module packaging concept here: In this article, I would just like to summarize the most important points, and give you some additional tips on how to extend the functionality. Building modules in Kentico 9 With version 9, we provide an even more solid platform for building modules. Because modules will be packaged into NuGet packages, we need to create them with the right structure, so that only relevant content is included. The first and most important thing is registration of your module. You need to carefully choose the module code name, because you will often use it as a prefix for other related data and code. For the purposes of this article, I will just use a simple code name “MyModule”. But in reality you may want to prefix your module names with the name of your company to avoid potential conflicts with modules from other authors. Here is an example of a prefixed name: “Acme.MyModule”. Similar naming conventions will also be used in other parts of the process. Module code On the code side of things, this means a Visual Studio project with the same name as the module (or at least producing an assembly with the same name), possibly supplemented by additional class libraries. This project must be a Web application project or a class library and its content must not overlap with other projects in the Kentico installation. For this reason, modules must be developed on Web application type installations of Kentico. Web site installations would automatically include unwanted files if you needed to add content to the web project. It is also strongly recommended to build module projects on the lowest .NET framework version supported by Kentico to ensure that the module works with all supported versions when deployed. Kentico libraries have a fixed version in all hotfixes of the given version, and the API never changes between hotfixes, so you don’t need to worry about them. Your module will work with any hotfix (if implemented properly). Installation of modules can be done on both Web application and Web site installation types, because at that point the module is already compiled. Modules automatically include the following folders when they are packaged: App_Data\CMSModules\MyModule CMSFormControls\MyModule CMSModules\MyModule CMSScripts\CMSModules\MyModule CMSResources\MyModule CMSWebParts\MyModule MyModule is the code name of your module. We also recommend placing any module related code to a folder matching the module name, e.g. MyModule This code will be compiled to the module assembly if you make a module project as described in the documentation, but not included into the package as physical files. Because my main focus in this article is on the data included into the module package, I created a module without the project file and code files. Learn more about the code part from the documentation, specifically the chapter Creating the module project. Module data As you can read in the documentation, module packages automatically include several object types which are commonly provided by modules. The list includes object types that we identified as the most important with our clients and managed to cover and test within the available development time. The following types of objects can be automatically included: Module UI Elements Permissions Settings Classes Web parts and categories Form controls Page types We know the list is fairly small, but it is a good start. If you are missing something important that you think should be supported by default, let us know. Read further to learn how you can extend this list through customization. There are just two general rules you need to remember in order to include objects with a module: If the object has a module selector field (typically a drop-down with a list of registered modules), the system uses this field to select which objects of the type will be included when packaging modules. This approach must be used in cases where the code names of objects are somehow limited. We use it for page types for this reason. I don’t recommend using it for custom module classes as it is much more complicated to set up. If the object doesn’t contain a module foreign key, a naming convention is used to select module objects. The convention is a prefix made from the module code name. So in our case the convention would match code names such as “MyModule.ABC” and “MyModule.ABC.DEF”, or with the company prefix variant “Acme.MyModule.ABC” and “Acme.MyModule.ABC.DEF”. Use this variant as often as possible. There is no simple way to include objects without a module selector field or code name but these two should suffice for the vast majority of cases. Note that you can only include global objects to modules. Site-specific objects are not supported. If you need to distribute site-specific objects, you have to use regular export/import packages. I mentioned custom module classes. The fact is that currently only custom class definitions can be installed together with modules. If you would also like to install some data for those classes, you would have to build your module as two modules, one with the class definition and the other with the data, and install them one after another. Or simply import the data through a regular import package. Module packaging If you properly follow the rules, making a NuGet package from your module is a matter of just a few clicks. Navigate to the module properties where you will find a button called Create installation package. It gives you a dialog for reviewing what will be included with the module, and once you click Finish, it creates the module NuGet package for you. You can then submit the package to an official feed or register a local feed from your local disk in Visual Studio. Module installation You can install module NuGet packages the regular way just like with other NuGet packages. All you need to do is select the module in the NuGet package manager in Visual Studio and install it. After the package is installed, it is a good practice to rebuild the solution to make sure that everything compiles correctly (but typically you don’t have to do it for the module to work), and start the web application. What happens next is the installation of the module data. Kentico detects that there is a new module, and automatically installs its data (the object types mentioned earlier). Then the module is fully installed and can be used. Extending support for packaging other object types As I mentioned earlier, only a couple of object types are currently included in module NuGet packages. So I looked at some ways to allow you to include more object types in case you need them. The module packaging and installation wraps the export/import functionality among other things, so all you need to do is leverage ImportExportEvents, and let the export know which other data the package should contain. First create a new file defining the module entry point: ~/MyModule/MyModule.cs Here is the code for the module class: using System.Linq; using CMS; using CMS.CMSImportExport; using CMS.DataEngine; using CMS.Modules; using CMS.Scheduler; using CMS.Ecommerce; using CMS.WorkflowEngine; using CMS.WebAnalytics; using CMS.PortalEngine; [assembly: RegisterModule(typeof(MyModule))] public class MyModule : Module { public MyModule() : base("MyModule") { } protected override void OnInit() { base.OnInit(); ImportExportEvents.Export.Before += Export_Before; } private void Export_Before(object sender, ExportEventArgs e) { var settings = e.Settings; // My module export var moduleName = (string)settings.GetInfo(ImportExportHelper.MODULE_NAME); if (moduleName == "MyModule") { var objectTypes = new[] { TaskInfo.OBJECT_TYPE, // Scheduled tasks PaymentOptionInfo.OBJECT_TYPE, // Payment options WorkflowActionInfo.OBJECT_TYPE, // Workflow actions ActivityTypeInfo.OBJECT_TYPE, // Activity types }; // Select only objects that match the module code name prefix settings.SelectGlobalObjects(objectTypes, resourceName + "."); } } } This simple piece of code does the following: Attaches additional code before the export happens Detects that the export is part of the module package creation process for my specific module (the condition could be more robust but this one should suffice in most cases) Defines a list of additional object types that should be included within the module export Preselects objects of these types based on the given prefix, in my case “MyModule.” This tells the module packaging to include the specified additional objects to the package based on the same naming conventions that we use for other objects. I used just a few object types as an example, but you can extend this list as you wish. All you need to bear in mind is that all such objects must have a code name column and be global objects, not site-specific. If you then examine the content of the NuGet package (the package is basically a zip file), you can easily verify that all such objects were correctly included: Note that these additional objects won’t be visible in the module packaging dialog. You need to review them by looking at the package content. Now when we install the module, all such objects will be installed together with the module. The installation process automatically takes everything included in the package. If you would like to provide this same functionality for multiple modules, it may make sense to place the code into a global folder rather than a module specific folder, or simply build a simple module that just extends these possibilities for you. Uninstalling extra object types with modules Removing objects of the extra types added through customization may be tricky, so be careful about it. You don’t want to lose other data. Currently the only way to do this is to use an uninstall SQL script which you can add to your module. So in my case I will create a file ~/App_Data/CMSModules/MyModule/Uninstall/before.sql with the following code: DELETE FROM CMS_ScheduledTask WHERE TaskSiteID IS NULL AND TaskName LIKE 'MyModule[.]%' DELETE FROM COM_PaymentOption WHERE PaymentOptionSiteID IS NULL AND PaymentOptionName LIKE 'MyModule[.]%' DELETE FROM CMS_WorkflowAction WHERE ActionName LIKE 'MyModule[.]%' DELETE FROM OM_ActivityType WHERE ActivityTypeName LIKE 'MyModule[.]%' This code is executed at the moment the module is being uninstalled from the instance, allowing me to remove all the custom data I included in the package. I used the corresponding data tables for each of the object types I included and deleted them based on the same prefix naming convention I mentioned earlier. Be careful with these conditions and never execute delete statements without specifying and validating the where condition first. Always start by verifying the expected set of data using SELECT before you DELETE. Wrap up Module packaging and deployment is easy! Today, you learned about: Module name best practices Module code folder conventions Module data naming conventions Packaging and installation Extending the supported object types I will get back to you soon with my next article. Jan 14, 2016 Hi,There were not so many changes in v9 in the way how modules are exported / packaged, so it should work in 8.2 as well. Wan Yuee commented on Dec 23, 2015 Thanks for the great write-up!Firstly, It has been mentioned in the official K9 docs that the "Page Type" under "Module Data" section was added in Kentico 9.Other than this, is there anything in the article that only applies for Kentico 8.2?Secondly, does the "Extending support for packaging other object types" work with Kentico 8.2 ? New subscription Leave message Your email: | https://devnet.kentico.com/articles/module-development-packaging | CC-MAIN-2017-51 | refinedweb | 2,126 | 53.51 |
Event Statement
Declares a user-defined event.
Syntax
[ <attrlist> ] [ accessmodifier ] _ [ Shared ] [ Shadows ] Event eventname[(parameterlist)] _ [ Implements implementslist ] ' -or- [ <attrlist> ] [ accessmodifier ] _ [ Shared ] [ Shadows ] Event eventname As delegatename _ [ Implements implementslist ] ' -or- [ <attrlist> ] [ accessmodifier ] _ [ Shared ] [ Shadows ] Custom Event eventname As delegatename _ [ Implements implementslist ] [ <attrlist> ] AddHandler(ByVal value As delegatename) [ statements ] End AddHandler [ <attrlist> ] RemoveHandler(ByVal value As delegatename) [ statements ] End RemoveHandler [ <attrlist> ] RaiseEvent(delegatesignature) [ statements ] End RaiseEvent End Event
Parts
Remarks
Once the event has been declared, use the
RaiseEvent statement to raise the event. A typical event might be declared and raised as shown in the following fragments:
Public Class EventSource ' Declare an event. Public Event Log,
ParamArray arguments, or
Optional arguments. Events do not have return values.
To handle an event, you must associate it with an event handler subroutine using either the
Handles or
AddHandler statement. The signatures of the subroutine and the event must match. To handle a shared event, you must use the
AddHandler statement.
You can use
Event only at module level. This means the declaration context for an event must be a class, structure, module, or interface, and cannot be a source file, namespace, procedure, or block. For more information, see Declaration Contexts and Default Access Levels.
In most circumstances, you can use the first syntax in the Syntax section of this topic for declaring events. However, some scenarios require that you have more control over the detailed behavior of the event. The last syntax in the Syntax section of this topic, which uses the
Custom keyword, provides that control by enabling you to define custom events. In a custom event, you specify exactly what occurs when code adds or removes an event handler to or from the event, or when code raises the event. For examples, see How to: Declare Custom Events To Conserve Memory and How to: Declare Custom Events To Avoid Blocking.
Example
The following example uses events to count down seconds from 10 to 0. The code illustrates several of the event-related methods, properties, and statements. This includes Forms project. Then previous example, and click the button labeled Start. The first text box starts to count down the seconds. When the full time (10 seconds) has elapsed, the first text box displays "Done".
Note
The
My.Application.DoEvents method does not process events in the same way the form does. To enable the form to handle the events directly, you can use multithreading. For more information, see Managed Threading. | https://docs.microsoft.com/en-us/dotnet/visual-basic/language-reference/statements/event-statement | CC-MAIN-2021-49 | refinedweb | 414 | 55.64 |
Let’s move into another interesting sections, the database where we store information processed. In this post we are store data into local SQLite database/
Denodb-ORM
This is a third party ORM module for deno which will help us to connect MySQL, MariaDB, SQLite and Postgres databases. The ORM module work through Model, so we can perform operations using Model, no worry about confusing, queries and statements.
APP
Our app is a simple Todo application, which store Todo’s in a MySQL database.
- create a configuration
- Create a SQLite file
- Create Models
- Link Model and Sync
Configuration
Usually we kept the database file under a config folder, the name of our file will database.ts and content s follows. In the final steps of the configuration we export the model.
import { Model, Database, SQLite3Connector, DataTypes } from "../deps.ts"; const connector = new SQLite3Connector({ filepath: './database.sqlite', }); const db = new Database(connector) // NOTE Models class Todo extends Model { static table = 'todos'; static fields = { id: { type: DataTypes.INTEGER, primaryKey: true, }, item: { type: DataTypes.STRING, } , description: { type: DataTypes.STRING, } }; } // NOTE Linking Model with DB db.link([Todo]) await db.sync() export default Todo;
Sync () – will create the tables for you. You have to create the database which in not created by the sync. | https://developerm.dev/2021/02/15/sqlite-app-using-denodb-in-deno/ | CC-MAIN-2021-10 | refinedweb | 210 | 58.99 |
I know, I know, you are probably thinking oh no not again. However, most articles on this subject seem to be very biased towards Python, using flawed arguments that do more to expose the author’s lack of understanding of Perl rather than shedding any new light on the subject. Hopefully this article will do better and help redress the balance.
If you like or even love using Python then please use it. What ever makes you happy, I mean it. A happy developer is usually a much more effective one. Everyone has their own likes and dislikes. However, If you are trying to decide between the two languages or are simply curious then please read on.
Firstly I must state that I am a big fan of Perl 5 and less so of Python, but none the less I have tried to be fair and objective.
Perl
Some of the more common criticisms levelled against Perl are listed below along with my thoughts on the subject:
Sigils
These are special characters that are used in Perl to denote different basic data types (such as scalar, array, hash, function, symbol). These are often cited as white noise that clutters up the program text. This is a perfectly valid criticism.
The reason Perl uses these sigils is because it was born out of a Unix shell scripting environment where the use of such sigils is widespread amongst the other scripting languages that were around at that time (and still are). One can also see other features of the language that owe their existence to these shells.
Another reason is that Perl always knows that a variable is a variable and not something else. If a new reserved word is introduced in Perl then there would be a much reduced risk of a clash with existing code (remember the hassle over C++ introducing the
new reserved word and how much ported C code had to be changed to rename variables called
new). Also languages that do not use sigils usually stipulate that variable identifiers have to start with a letter and may only contain alpha-numerics and underscores. Perl’s variable identifiers need not be so restrictive.
Whilst I do agree with this criticism, I have not found the use of sigils to be an issue. Indeed occasionally it has even helped to remind me of what I am dealing with.
Perl Is A Write Once Language
This criticism says far more about the person saying it than it does about Perl. The only reason write once code exists is because the person who wrote it is either inexperienced at writing software, incompetent or lazy.
There are a couple of things to bear in mind. Perl is a very forgiving language. I have often heard people say `I didn’t quite know how to write this code but I typed it in and it just seemed to work’. Perl will bend over backwards to work out what you mean before giving up. The second point is that Perl provides shorthand notations for commonly used idioms that are useful in one line script snippets given on the command line.
However, there are consequences to this. One can throw terrible code at Perl and there is a better than average chance that it might actually work. Also people think that it is clever to use those shorthand notations in proper programs. It is not. In fact it is quite the opposite.
As a consequence of the first point Perl has an inclusive community where people who are not software engineers quite often contribute useful stuff that does the job perfectly well but is less than desirable from a coding point of view. These people may range from scientists and business people to artists. You also get the smarty pants type that likes to show off how awesome they are (invariably ending up doing the opposite).
Writing good maintainable code takes effort, experience and real skill. Just because Perl allows you to write bad code does not mean that you should not write good code. The same can be said of C and C++.
For an example of well written Perl code you can have a look at Completion.pm, which is a module in my mtn-browse application.
Anyone care to tell me what this C program does?
#include <stdio.h>\ l]!'/ ') }+}{rl#'{n' ')# }'+}##(!!/") :t<-50?_==*a ?putchar(a[31]));}
No? This was the winner of the C obfuscation competition one year.
At the end of the day I would much rather use a programming language that allows me the freedom to do what I want rather than have it constrain me. As they say with Perl ‘There is more than one way to do it’.
Perl 5 I Dead And Perl 6 Has Not Arrived Yet
No Perl 5 is very much alive and is not going to disappear, any more than C or C++ will. It is actively being maintained and enhanced like any other popular and current programming language. Indeed it is taking on board some of the really cool ideas coming out of Perl 6.
Perl 6 will be out for Christmas. Unfortunately no one remembered to tie down exactly which Christmas! Perl 6 is a really bad name for the language as it is not a replacement for Perl 5 as 5 was for 4. It is almost a different language and is regarded as a spin-off or sister language and not a replacement. Unfortunately the name Perl 6 stuck and this has caused quite a lot of unnecessary confusion.
Perl Does Not Do Object Oriented Programming Well
No it is not as nice to write classes in native Perl as in Python. Then again the same would be said of C++ and Java. Python excels at making this stuff simple.
OO was not built into Perl in the same way as it was with Python. However it is still easy to do:
package Organism; sub new { my $class = shift; my $self = {}; $self->{organism} = 1; return bless($self, $class); } package Animal; use base qw(Organism); sub make_sound { my $self = shift; print("$_[0]\n"); } package Dog; use base qw(Animal); sub new { my $class = shift; my $self = $class->can("SUPER::new") ? $class->SUPER::new() : {}; $self->{name} = undef; $self->{sex} = undef; $self->{no_of_legs} = 4; $self->{eats} = "meat"; $self->{noise} = "barks"; return bless($self, $class); } sub bark { my $self = shift; $self->make_sound($self->{noise}); }
The above defines a class called
Dog that is derived from the
Animal class, which in turn is derived from the
Organism class. It defines an additional
bark() method and its constructor sets up a few new attributes.
One could then use the above class like this:
package main; my $dog = Dog->new(); printf("My dog has %d legs.\n", $dog->{no_of_legs}); $dog->bark();
The above is raw Perl code. There are packages one can use that take the tedium out of writing classes in Perl. The best know is called Moose. However, personally I have never found it an issue simply writing classes directly in Perl.
Incidentally Python represents objects in essentially the same way under the skin, dictionaries with meta-data attached to say what class it is.
Perl Does Not Scale For Large Projects
Oh yes it does! I have written ~18,000 line programs in Perl (excluding comments and white space) without any issues of scalability. It supports name spaces, private data and functions, modules, packages etc.
Again this is down to the competence of the people using the language.
In fact one could argue that Perl is more scalable than Python as Python has no true concept of data privacy (just obfuscation).
Perl Does Not Handle Argument Lists Nicely
Granted it does not. But it is not such a big deal:
sub draw_box($$$$) { my ($x, $y, $width, $height) = @_; ... }
One can also do named arguments as well:
sub print_message(@) { my %args = (text => "(null)", colour => "black", row => 0, column => 0, @_); ... } print_message(text => "Hello world", colour => "Yellow");
But no it is not as nice as in Python.
Perl Has No Interpreter Shell
Yes it does. It is its fully fledged very powerful debugger. Simply do
perl -d and then
Ctrl-D to end the input of program code and you have an interactive Perl interpreter.
Granted this approach does not give you everything but it is certainly enough to try stuff out in.
Perl Is Not Portable
Utter nonsense! It is as portable as Python. Both are available on MS-Windows, MacOSX and assorted Unixes. I have written Perl scripts on one platform that just work on the other.
It is true that Perl’s run time library owes a lot in look and feel to C’s runtime library on Unix but this is more about the style of the API. It still works the same way on MS-Windows. Obviously there are differences between platforms, where certain features of one are not available on the other, but you have packages that help get the best out of that platform as you do with Python.
Where Are Its Batteries?
Sorry I could not resist that! This refers to the batteries included phrase often used in conjunction with Python to denote the fact that it comes with a very feature rich standard library.
Perl does come with a very good standard set of libraries but they are not quite as all-encompassing as those that come with Python. The reason is Perl has CPAN (Comprehensive Perl Archive Network). This is a site offering a vast array of packages for all sorts of useful things. This is quite often referred to as Perl’s Killer App and provides many more modules and libraries. Python currently has nothing as extensive or as mature as CPAN. CPAN modules are also very easy to install. Most can be installed in an automated fashion these days.
In short with Python you are less likely to want to go and download additional libraries, but if you do it may be harder to find what you want. With Perl it is more likely that you will need to download extra stuff but invariably you need look no further than CPAN.
Perl’s Libraries Are Ugly To Use
This is usually said in reference to the fact that Perl’s libraries were only procedural and used clunky global file handles. This used to be the case, and it is still supported for backward compatibility reasons, but there are now OO interfaces for most libraries and global file handles are no longer necessary.
For example to open a file and display its contents one could do:
use IO::File; sub cat() { my $line; my $file = IO::File->new("/etc/hosts", "r"); while($line = $file->getline()) { print($line); } } cat();
Notice how I did not close the file. I could have used
$file->close() but I do not have to because when
$file goes out of scope the file is automatically closed by
$file‘s destructor.
Python
When I went on the Python 3 course I was looking forward to learning a new language and seeing what all the fuss was about. Whilst there were many times that I thought `hmm that is nice’, time and time again I caught myself thinking `oh no I can’t believe it does or doesn’t do that’. It seemed that every bit of enthusiasm was knocked back by an even bigger concern or disappointment.
Basically I found Python to be a very nice idea poorly thought out and executed. The initial start-up project for Python could have done with someone more experienced in language design.
I have written tens of thousands of lines of Python code and have done some meta class programming so I have not just dabbled but actually used it in earnest for work.
Some of my observations, both good and bad, are listed below:
Batteries Included
One of best things about Python is that it comes with a very comprehensive standard library. Most of the time you will not need to go looking elsewhere for something. Probably the only thing I can think of is bindings to a decent graphics library like Gtk2 or QT4. However there is no Python equivalent of CPAN in both its size and maturity.
Cleaner Syntax
Regardless of some points raised later. There is no denying that Python code does look cleaner. Whilst it does make use of sigils, they are far fewer in type and are mainly concerned with data obfuscation.
Many Different Versions
Python is still suffering from that initial churn that you get with a relatively new language. This is not a fault of Python as this happens with any newish language. It takes time for things to settle, solidify and calm down. But on projects using Python you constantly hear the phrase, `oh you must use version x or later’. That just does not happen with Perl.
In my experience Perl scripts just tend to work regardless of the version of Perl being used (assuming the version 5 family). We have used Perl on RedHat 9 up to the latest Linux with little to no issues. However one Python network component got rewritten in C to avoid the constant issues with Python versions natively installed on the machines (being a testing environment we did not want to mess around with the systems by putting later versions of Python on them).
Just something to bear in mind. This is getting less of an issue as time goes on.
Syntactic White Space
Oddly this is not a show stopper for me as for some people. However, syntactic white space is a bad idea. There are good reasons why nearly all popular programming languages do not use it.
Things not good about this include:
- It makes the language brittle. Indentation can easily get mangled in emails, on wikis or when editing source code in a different editor. Even cutting and pasting code can be an issue where the pasted code is inadvertently left at the wrong indentation level. I had more indentation issues in three months of programming in Python than I had with missing braces in twenty years of C/C++ programming.
- You can limit the syntax. What about having a do-while loop in Python? No can do unless you want some awful kludge.
- It is often difficult to see how much you need to come out of some deeply nested code, especially if you are coming out a couple of levels in one go. Syntax aware editors cannot help you as they can in say C or Perl. Also curly braces act as a very useful visual clue as to when some nested block finishes (remember that statements wrapped over multiple lines will typically have their continuation lines indented, thus mucking up any nice visual clues as to nesting and structure).
- Tabs vs spaces and misguided attempts at redefining the size of tabs within editors! Enough said on that one.
- Lastly, I read somewhere on a Python site that the initial reason for using syntactic white space was because it was seen as a challenge. Perceived wisdom in language design circles said that no high level and powerful language could successfully make use of syntactic white space. Unfortunately I now cannot find the reference. However, if true, one should always have a better reason for introducing a language feature than because it has not successfully been done before. It has to be of use and make the language better.
Unreliable Destructors
In my view an OO language that does not call an object’s destructor as soon as that object goes out of scope is not a language I wish to use. This is such a useful feature of C++ and Perl and allows you to do some very powerful scope based operations. For example, scope based mutex locking that will automatically unlock should an exception be thrown.
In Python using destructors is frowned upon. I did not understand this at first as they seemed to work fine. Indeed any discussions as to where they may not work revolved around edge cases that I was more than prepared to accept (apart from the exception handling scenario, but even that can be handled).
Then the answer came to me in the form of Jython (a Python interpreter written in Java). In C Python (the main Python interpreter written in C), destructors behave as one would expect in a reference counting system, all was good. However in Jython it simply uses Java’s garbage collector and hence Jython destructors get the same lame and useless behaviour as that seen in Java.
Nothing stipulates the precise behaviour of any garbage collector that may be used in the implementation of a Python interpreter. Thus C Python happens to use reference counting at the moment, but this may change in the future. Also Jython can get away with simply using Java’s garbage collector. Indeed there is even some talk of putting a Java style garbage collector into C Python.
But why is this so important? When the memory gets freed up does not matter? No it does not, in fact interpreters can often make more efficient use of their heap by not freeing up memory straight away. However, it is not about memory, it is about other operations that may need to be done like closing files, dropping network connections or closing databases. Being able to do this in a destructor means that these things automatically get cleaned up when exceptions get thrown or you simply return early from a routine.
One can also do neat tricks like scope based locking. Indeed there is a design pattern in C++ where a library developer can enforce that you can only take out a lock as a scope based lock, thus drastically reducing the likelihood of deadlocks occurring due to badly written code.
For a specific article discussing the benefits of what is commonly referred to as RAII please look here.
In Python 2.5 they introduced the
with clause. This does help. However this is nowhere near as elegant as RAII. Firstly you have to remember to use
with, rather than simply enforcing policy in constructors and destructors (that incur no extra effort on the users of those classes) and secondly this introduces more stuff that is not necessary if RAII were used (
__enter__ and
__exit__ operators and the
with clause itself).
Syntax
Python has made some weird and ugly syntax choices. A lot of languages get their syntax from C. C uses a nice clean syntax that can cope with multi-line if clauses.
Python makes use of the colon to denote the end of certain parts of its syntax. This is ugly as it shouts out at you and there is no need for it if a bit more thought had gone into it. I keep thinking of labels or name separators.
This is the one ugly thing about Python. I know it is probably a personal pet hate, but there you go.
As for the rest of it some things are different, I miss the
++ and
-- operators but I like how their
for loops work and how classes are defined.
Another thing that does bug me a little is when everything is supposed to be OO, why are there procedural ways of doing things? For example, if you want to find out the length of a list you do not do
myList.length() but
len(MyList). If one wishes to enforce a standard way of getting the length of something then one could always put that into a style or API guide.
Non-Standard Scoping
Even if Jython was just someone’s idea of a bad joke and destructors were specifically designed to always behave like they currently do in C Python then Python’s scoping rules would shoot you in the foot!
Once a variable has come into existence it remains until the enclosing function exits and not when the enclosing block terminates. So bang goes any idea of scope based locking done by mere class definitions, constructors and destructors.
I wonder how many people coming to Python have been caught out by this?
I know you could use the
with clause to deal with cases where this was an issue, but as I said before, this is an inelegant solution.
Closures And Anonymous Functions
Closures seem to work in a rather clunky way. However they do work. I have found the need to use container objects rather than scalars, certainly if you want to pass anything back to the outer scope.
Anonymous or Lambda functions are also limited in their ability. However one can declare a named function in an inner scope and use that instead.
In Perl anonymous functions have the same capabilities as named ones. It is especially nice to use them inline inside function calls for registering small one-off callback functions in a GUI program.
No Data Privacy
Python has no concept of data privacy, only obfuscation.
Python has two levels of obfuscation:
- Identifiers that start with a single underscore denote a weak internal use only entity. It is really a warning this is actually private convention. In fact I think the only case where any attention is paid to the single underscore is when they are ignored during a
from ... import *. However, such variables can still be accessed by doing
<Package>._.
- Identifiers that start with two underscores denote something that is private to a class and are actually altered to have their containing class prepended onto the front of the identifier. This is really meant as a means of making sure that attributes within a class do not interfere with other attributes in base classes. However, again one can simply prepend the class name onto the front of the identifier to get at it.
Python is quite open about how the above works and the intention of the double underscore. Neither enforces privacy.
On the other hand Perl does support privacy. Anything declared as a
my variable at the file scope level is only accessible from within that file, period. The only way Perl code can access another file’s
my variables is by modifying that file to make them non-local or to provide accessor functions.
Routines can also be made local to a file with something like:
my $private_func = sub { ... } ... &$private_func();
Although this is less common.
No Variable Declarations
In Python variables simply come into existence when you assign something to them, there is no concept of explicit declaration.
This is such a pain! Firstly let us not forget the obvious question. What happens if you mistype the name of a variable that already exists? Well if you are assigning something to it then that assignment gets lost in another variable, if you are reading from it you get a run time exception. Grim.
Another issue is that this leads to ambiguity when you have multiple scopes. So instead of having one simple
var keyword, Python has the
global and
nonlocal keywords (the latter is only available in Python 3).
More Errors Are Detected At Run Time Than Is Desirable
Certain mistakes in the code are only detected at run time and not at compile time. The best example of what I mean is the case of a mistyped variable. If you accidentally reference a non-existent variable, because you mistyped the name, you do not get a compile time error as you would expect, but rather the program runs normally and then should that offending piece of code be executed you get a run time exception.
This is grim. Basically you have to make sure that all your code has been executed before you can say that the program is even semantically correct.
Of course with dynamically typed languages like Perl and Python, there is a tendency towards certain things being detected at execution time that would otherwise have been detected at compile time with say C or C++. For example, type mismatches are only detected when the offending code is actually run. But this issue is much more noticeable in Python.
Some people say that this is normal behaviour for an interpreter. However this is completely incorrect. Whether you use an interpreter or a compiler is irrelevant, they are just the means by which the code is run. It makes no difference as to what errors can be picked up before execution of the code commences.
What does influence this is the design of the language. For example, by not having variable declarations, Python cannot detect semantic errors like assigning to variables with misspelt names. Another example is to do with operators. Perl has operators dedicated to string handling where Python uses generic arithmetic operators. One can argue the merits of using a `.’ operator for string concatenation versus `+’ (some would argue that using `+’ is wrong since concatenation is not commutative), but one fact is undeniable, using `.’ removes any ambiguity. Thus Perl always knows when to convert something into a string or a number. Python does not. Issues like these are why Python reports such things as run time exceptions rather than silently converting the data type for you.
Data Typing
Python is highly typed. This may sound like a good idea. However you have some of pedantic pain that comes with tight data typing without some of the benefits.
For example, as mentioned previously, Python can only raise an exception when adding a number and a string together rather than silently converting the number. Ok you would have to do the conversion in C or C++ but at least it would fail during compilation if you skipped the conversion step. So what about the advantages? Do you get function overloading based upon parameter type? No. Can you stipulate the type of a parameter in a function declaration? No, this has to be coded within the function.
For it to work properly you would really have to go all the way and be able to declare typed variables and parameters up front and explicitly. I.e. ditch dynamic typing altogether, or at least have separate categories of operator for basic types.
Documentation
The documentation that comes with Python is generally well laid out and it is pretty easy to find the subject matter that you are after. However I have found that it quite often does not go into enough detail. There is an awful lot to cover with Python and so hopefully in time this will get better.
Conclusion
Despite its often cited shortcomings, Perl is a language that I have steadily come to respect and to be impressed by. I have found it a delight to use and quite intuitive and forgiving. I can get things done reliably and quickly and it is great fun doing it. I can concentrate on coming up with a solution to a problem rather than getting bogged down with the very low-level stuff as one can do in C. I have also been impressed with its speed and robustness.
Largely the same can be said of Python. However, when learning the language, both on a course and then using it for real, any enthusiasm for the language was invariably quashed by some fundamental flaw or oversight. I feel it is a language that had true potential to be one of the all time greats if it were not for some ill thought out design and implementation details. Which is a great pity as Python started from a clean slate and so could have avoided most if not all of these unnecessary pitfalls.
If you are used to the traditional shell scripting languages in use on Unix then once you start using Perl you will never look back.
However if you are coming from a completely different background and do not find the points I raised against Python to be of huge concern then you might want to give Python a go. There are a lot of good and novel things about this language.
One thing I would say is that if you are looking to learn how to program then be aware that Python does have a unique syntax and style, not sharing that much with other languages. Another language you may wish to consider in this case would be Java.
At the end of the day, you will not go far wrong with either language. The most likely thing is that the job will dictate what language you use.
What ever you decide, enjoy it and have fun
.
That’s a lot of needless function prototypes in the sample code…
Hehe To each their own. I know that currently there is a move away from prototypes in Perl code but I happen to disagree. I have found that having forward declarations and prototypes have picked up little mistakes and inconsistencies that have been made during coding long before it ends up wasting serious time down the line. Also in the code snippets above I feel that having the prototypes emphasise what basic types are expected as arguments would help.
The problem is that the use of prototypes above is based on an incorrect mental model. They are a great help when writing functions that behave like built-in functions (grep, map, push…) but are actually ignored completely when called as methods on objects or classes.
See my reply below to confuseACat…
column => 0.
@_);
That won’t do what you think😉
Ha that is a classic! Many thanks for spotting the typo. No string concatenation was not what I had intended…
package Organism;
use base qw(Exporter); # <- Why this ? I don't think it is needed in this case.
Cheers, yes force of habit, I usually export constants etc when writing a class. Will remove.
Your prototypes are useless in the literal sense of the word: Perl will not look at a prototype when you make a method call. $obj->method will always work, no matter how you define “method”. Please read
This is addressed to bleh as well.
Ok, I shall expand upon my previous answer…
Firstly I am well aware about the caveat regarding methods and prototypes. The reason being that what method is actually called is determined at run-time when the
@ISAlist is traversed.
However in a procedural context they are checked when called directly without the
&sigil and errors are generated if mismatches are found. One can either 1) not use prototypes and be free to use forward function calls, 2) use prototypes and either forward declare prototypes or 3) order stuff such that forward prototypes aren’t required. I personally where possible go for option 2 in any language. I get the benefit of prototypes and no restriction on ordering.
The advice about only using prototypes to get built-ins type syntax was only discovered by me later after I had been using Perl for some time. By that time I had benefited from the errors about prototype mismatches on quite a few occasions and so stuck with it as it had clearly helped (it’s so easy to add an extra argument and forget to update all call occurrences later on).
Most programs, even if they are OO, use a lot of procedural code as well. OO is only relevant to a design some of the time (a mistake that is often made is to think it applies all the time). Thus I would end up with procedural code using prototypes, where it is of use, and OO code that doesn’t, because they are ignored. Consequently I decided to be consistent across the board. Also if you take the forward prototype route in class modules it can still pick up inconsistencies between prototypes (and this has happened), just not when they are called in code (unless done so procedurally within the class itself).
Upon reflection since some people reading this would not know about the above restrictions to prototype usage I will remove them for the OO stuff. Not to do so, I agree, would be misleading. However, they can only help procedurally though.
You’ve unfortunately been put in the spotlight because of blogs.perl.org. So I am honestly sorry about this, but a couple of minutes gave me this from that codebase:
You use a prototype of ($) on instance, but a prototype of () on update_gui. You then call instance as:
my $wm = WindowManager->instance();
And update_gui as:
$wm->update_gui();
See where the two calls are next to each other.
How does the prototype help?
Are so that is the reason for the sudden interest
. Cool
.
Firstly the inconsistency came about because update_gui is really standalone and then got sucked into a class. But thanks for pointing that out anyway.
My reply to confuseACat pretty much covers the prototyping thingy
. But to answer your specific point… Totally agree that prototypes for OO are ignored and don’t help programatically, I actually knew that when writing the code. So why do it? Most of mtn-browse is procedural with a few OO helper classes dotted around the place. The procedural stuff (~90-95% of the code) directly benefits from the prototypes as I don’t use the
&sigil when calling functions. Inside the OO modules it is primarily done for consistency (the forward prototypes also pick up inconsistencies (most of the time) in the OO packages as well – before now I have added a parameter, been distracted, went to run the code and boom – then gone oh crumbs yes forgot to update forward prototype and all calls to method or words to that effect at least!).
But since this is a coding style thing I have removed prototypes from the OO examples because that would probably mislead people not familiar with Perl.
By the way, thank you for engaging with everyone who’s commented in a positive way. It’s great. It’s good that you spend the time to think about the Perl you write. I disagree with your style (Moose/Moo and Method::Signatures changed my life😉 ) but at the end of the day, TIMTOWTDI.
My pleasure. Much rather have interest and debate than complete dis-interest
. You also get other people’s input and interesting links. Admittedly this post was something I wanted to get off my chest having seen some of the other blogs on this topic, redress the balance a bit.
About sigils: Yes, the shell scripting legacy sure is part of the explanation. But: they also helped to keep the language evolvable. Languages without sigils tend to have rules like “variable names may contain blah and may not be reserved words.” The latter is absent in perl. The language designer can add reserved words and he will not have to worry about breaking existing code because perl’s parser, thanks to sigils, always knows when a variable is a variable.
Cheers, forgot about that. Will update.
Btw, Perl has two REPLs – as usal on CPAN:
Devel::REPL and re.pl – you don’t need to jump into the debugger.
Other advantages of Perl to note are its Unicode support and its functional capabilities (see the book Higher Order Perl).
Perlbrew is worth mentioning as well (It’s what rvm is in Ruby and virtualenv/pythonbrew in Python).
Another advantage of Perl is the VAST corpus of testing modules – it ranges from simple tests for Babyperl to extremely high end testing frameworks like Tapper.
A clear disadvantages of Perl is the way you have to write C bindings via XS, it works but it’s not really simple.
And let’s not forget that both Perl and Python have PDL and SciPy/NumPy.
Also: Yes, don’t use prototypes unless you really really know what for and why and then maybe & is one of the more useful examples…
As in JavaScript, you better look a little more closely which feature you really should be using in Perl. Consider “Modern Perl” the Perl equivalent of “JavaScript the good parts”.
In case you’re wondering what people write in Perl these days, just use DuckDuckGo as your search engine..
Cool many thanks for the extra info
.
This is the kind of post I was looking for (and its comments, of course). One more objective. I’m not an experienced programmer; just started reading the Camel Book, and this matter is something I really wanted to clarify before continuing with it. So, thank you.
Good read, but Python a relatively new language? Seriously?
Firstly thank you for your comments.
As for your point. The age of a language is not only measured in years but also in how it feels. Python does suffer from feeling like a language that was rushed into rather than thought out carefully. Really quite important features have only arrived later on in the 2.x series that should have been there much earlier or not even needed had they made the right decision and gone with the RAII approach. Some much needed improvements have only just arrived in series 3.x.
When I originally found out when Python 1.0 had been released I was surprised. I had assumed that it came out around 2004-2005 and not 1994. It just felt too rough around the edges in certain respects. Likewise Pypi has a rough and ready feel when compared to CPAN.
Complex languages do take a long time to mature and Python is no exception.
You made consideration that nobody makes, and with these considerations you came to the conclusion:
– nobody says that perl is not portable. Everybody knows that perl runs on every OS, and every CPU architecture.
– “where are its batteries”. Again, everybody knows about CPAN. Nobody would make this question.
– “In Python variables simply come into existence when you assign something to them.”. I think this is not a python characteristic. Each and every language behaves this way. The exception if I am not wrong is Perl.
Firstly thank you for your feedback.
With regard to your first two points. Unfortunately some developers do make these assertions, a surprisingly significant number of them, even ones that have used Perl in the past (presumably in a limited way). One can understand not knowing about CPAN, it is only relevant if you use Perl to a serious extent or in a specialist way.
In my own experience the most often cited criticisms/comments about Perl are:
Without discussion and debate with other developers these points, as you say, would seem self evident. Unfortunately ignorance and jumping to unsubstantiated conclusions is common-place.
As for your last point, I think there must have been some misunderstanding somewhere. I am not referring to a variable’s physical storage but how it comes into existence. Nearly all commonly used programming languages require one to declare a variable before using it, but not necessarily specifying its type. The only languages I can think of where this doesn’t apply are Python, basic scripting languages (like Bourne Shell, C Shell and Awk) and early versions of BASIC. Perl also does this by default but one can use a pragma to enforce declaration before use.
I’ve been writing Perl for a few years and just recently started Python. In Perl, I’ve always used POE for asynchronous programming but when there are bugs, it takes the whole thing down with it. In Python’s Twited framework, it just prints a traceback to the screen and moves on with more requests. I don’t know if that’s a good thing or not. Maybe I didn’t give much time to learn POE but it seems ridiculously complicated. Okay, but has nothing to do with the language itself, so I guess I like both languages but probably Perl more.
Thank you for your comments. I haven’t used POE myself, but I would have thought using exception handlers and eval blocks would trap and enable one to deal with errors. It sounds like this is what Python is doing.
I guess another reason is that Python always throws an exception when there is an issue. The core Perl APIs tend to return an error condition, it’s only the later libraries that tend to use exceptions. Usually when I write a Perl library I offer both options. Sometimes checking return values make more sense, sometimes exceptions do.
Yes both languages are great to use, but like you I prefer Perl.
Excellent Write up. There were way too many articles trying to tear down Perl. But this one clears a lot of FUD against Perl.
Thank you for this.
After 3 days with Python, I already noticed & relate to a lot of what you mentioned.
Also you probably can add pythons regex implementation,
as 1 days is all it took me to notice bugs in it.
rexp = re.compile(r”^(P)(ytho)?(n)”)
string=’Pyton’
print(rexp.sub(r”\1, \2, \3″, string)) #Aha
string=’Pn’
print(rexp.sub(r”\1, \2, \3″, string)) #Error
An anecdotal experience: I needed to do some FTP in python, along with some authentication from the .netrc file. Perl’s netrc library is transparently integrated with the FTP library and just works. With python, you need to deal with the netrc library separately to get the auth data for FTP. Plus, the netrc library has bugs with regard to spaces in quoted tokens, and machine directives without login or password directives. You would think such a ubiquitous library would be well-ironed out by now. Color me not impressed. I won’t even go into python’s mismash of database libraries in contrast to perl’s DBI, and python’s crippled poor excuse of a lambda statement. Slight props for list comprehensions and tuples, though.
hello.
personally i think if both python and perl can be used to achieve same result , then
its just a matter of taste.
i did some programming in both python and perl.
i like both languages.
Yes I do agree. My post was to more about trying to readdress the disinformation about Perl. Whilst both languages have specific strengths that doesn’t prevent either of them from being very good general purpose programming languages.
Thanks for your detailed comparison.
I regularly use Perl in Windows platforms to produce self contained .exe programs (via pp). It would be great if you could compare this with Python, since I’ve seen some python software that offers a windows executable (ie: gajim), so I know this exists for Python too.
I have to confess I have only superficially looked into this on Linux (I rarely use MS-Windows these days). I hear great things about ease of deployment etc. I have tried a few simple cases out of interest but generally ship my Perl as source module packages. But it’s certainly an area of interest
. | https://coosoft.wordpress.com/2013/02/24/the-perl-vs-python-debate/ | CC-MAIN-2016-18 | refinedweb | 7,154 | 71.55 |
CodePlexProject Hosting for Open Source Software
So i wrote a module without widgets. Now that i want to add widgets there seems to be a problem. Not sure if you just can't add widgets later on, or if i'm missing something.
I tried following
The widget needs to load data from an existing service. It doesn't require an adittion record in the database
Added to my existing module.txt
Features:
NopComCartWidget:
Name: Cart for NopCommerce
Category: Commerce
Description: Widget for show cart items and link to cart
Wrote this in migrations.cs
[OrchardFeature("NopComCartWidget")]
public class Migrations : DataMigrationImpl
{
public int Create()
{
ContentDefinitionManager.AlterPartDefinition(typeof(NopComCartWidgetPart).Name,
builder => builder.Attachable());
return 1;
}
public int UpdateFrom1()
{
// Tell the content def manager that we have a content type called TwitterWidget
// the parts it contains and that it should be treated as a widget
ContentDefinitionManager.AlterTypeDefinition("NopComCartWidget",
cfg => cfg
.WithPart("NopComCartWidgetPart")
.WithPart("WidgetPart")
.WithPart("CommonPart")
.WithSetting("Stereotype", "Widget"));
return 2;
}
I added a file called Placement.info
<Placement>
<Place Parts_NopComCartWidget="Content:1"/>
<Place Parts_NopComCartWidget_Edit="Content:7.5"/>
</Placement>
And wrote the needed driver, view and widgetpart.
When i now run the orchard project, the debug doesn't seem to break on the Create() methode of migrations.cs. Since their never where any widgets, I presume it should have broken. Nor does the widget show up on the content page.
Judging from the table Settings_ContentTypeDefinitionRecord it hasn't been added to the system either.
I've read about people having success after restarting their IIS. Or when they changed the number value of UpdateFromX().
Anyone who has an idea of what i'm still missing?
This just means that your migration already ran. Each step of migrations runs exactly once successfully. Unless you go into the database and hack the migration records, or you reset your database. Or you can write another step.
Are you sure you want to delete this post? You will not be able to recover it later.
Are you sure you want to delete this thread? You will not be able to recover it later. | http://orchard.codeplex.com/discussions/376437 | CC-MAIN-2016-50 | refinedweb | 347 | 51.44 |
German University in Cairo Faculty of Media Engineering and Technology Prof. Dr. Slim Abdennadher Introduction to Computer Science , Winter Term 2009-2010 Practice Assignment 4 Discussion: 31.10.2009 - 5.11.2009 Exercise 4-1 The simplest algorithm to search a list of Numbers N1,. ..,Nm for a given key Key is to test successively each element. get m get N1,. .,Nm get Key set i to 1 set FOUND to NO while (i<=m and FOUND = NO) { if (Key = Ni) then set FOUND to YES else set i to i+1 endif } if (FOUND = NO) then print ``sorry, key is not in the list'' else print ``key found'' endif If a list is already stored in increasing order, a modi ed sequential search algorithm can be used that compares aganist each element in turn, stopping if a list element exceeds the target value. Write a pseudocode for the modi ed sequential serach. Exercise 4-2 Write an algorithm to nd the maximum value stored in an (unsorted) list A1, A2, . .., An of n integers. Exercise 4-3
View Full
Document
This
preview
has intentionally blurred sections.
- Spring '09
- Slim
- Addition, Negative and non-negative numbers, Prime number
Click to edit the document details | https://www.coursehero.com/file/5686434/Practice4-2881/ | CC-MAIN-2017-30 | refinedweb | 204 | 62.17 |
Browse Source Download (without any required ccan dependencies)
tap
Test Anything Protocol
Rusty Russell <[email protected]>
The tap package produces simple-to-parse mainly-human-readable test output to assist in the writing of test cases. It is based on the (now-defunct) libtap, which is based on Perl's CPAN TAP module. Its output can be parsed by a harness such as CPAN's Prove.
CCAN testcases are expected to output the TAP format, usually using this package.
For more information about TAP, see:
Based on the original libtap, Copyright (c) 2004 Nik Clayton.
#include <string.h> #include <ccan/tap/tap.h> // Run some simple (but overly chatty) tests on strcmp(). int main(int argc, char *argv[]) { const char a[] = "a", another_a[] = "a"; const char b[] = "b"; const char ab[] = "ab"; plan_tests(4); diag("Testing different pointers (%p/%p) with same contents", a, another_a); ok1(strcmp(a, another_a) == 0); diag("'a' comes before 'b'"); ok1(strcmp(a, b) < 0); ok1(strcmp(b, a) > 0); diag("'ab' comes after 'a'"); ok1(strcmp(ab, a) > 0); return exit_status(); }
BSD (2 clause) | http://ccodearchive.net/info/tap.html | CC-MAIN-2022-27 | refinedweb | 180 | 51.78 |
Hi,
I’m working on an application where I need to auto-calibrate the recording level volume based on a standard that I establish. To do this, I plan on recording a few seconds of audio on the Line In channel from a known standard, analyze the volume of the recorded sample, and adjust the Record Level based on the results & iterate until I zero in on the expected value.
I’m currently using the following code (modified from the Pitch measuring sample) to measure volume but I keep getting a repeatable, unexpected result of -109dB if I use SPECTRUMSIZE=64 or -67dB if I use SPECTRUMSIZE=8192. I’ve manually adjusted the Line In volume but it doesn’t seem to matter.
Here’s my code:
[quote:arlfh8ie]public class DetectVolume
{
public int OUTPUTRATE = 48000;
public int SPECTRUMSIZE = 8192; //64 is the minimum # of values you can have in a spectrum
private float SPECTRUMRANGE = 0;
private float BINSIZE = 0;
public float Peak = 0.0f;
public float Average = 0.0f;
public float RMS = 0.0f;
public DetectVolume(FMOD.Channel channel) { SPECTRUMRANGE = ((float)OUTPUTRATE / 2.0f); /* 0 to nyquist */ BINSIZE = (SPECTRUMRANGE / (float)SPECTRUMSIZE); // // TODO: Add constructor logic here // GetVolume(channel); } public void GetVolume(FMOD.Channel channel) { if (channel != null) { FMOD.RESULT result; float[] spectrum = new float[SPECTRUMSIZE]; float dominantHzMin = 0.0f; float dominantHzMax = 0.0f; float dominantHzAvg = 0.0f; float max = 0.0f; int count = 0; int nonzeroCount = 0; int bin = 0; float sum = 0.0f; float avg = 0.0f; result = channel.getSpectrum(spectrum, SPECTRUMSIZE, 0, FMOD.DSP_FFT_WINDOW.TRIANGLE); ErrCheck(result); for (count = 0; count < SPECTRUMSIZE; count++) { if (spectrum[count] > 0.0f) { sum += spectrum[count]; nonzeroCount++; if (spectrum[count] > max) { max = spectrum[count]; bin = count; } } } avg = sum / nonzeroCount; dominantHzMin = (float)bin * BINSIZE; /* dominant frequency min */ dominantHzMax = dominantHzMin + (((float)bin + 0.99f) * BINSIZE); dominantHzAvg = (dominantHzMin + dominantHzMax)/2; AudioEngine.Update(); Peak = 10.0f * (float)Math.Log10(max) * 2.0f; Average = 10.0f * (float)Math.Log10(avg) * 2.0f; } else throw new ApplicationException("FMOD channel is NULL"); }[/quote:arlfh8ie]
If there’s an easier way to measure the volume of a recorded sample, I’d love to simplify my life.
Thanks for the help!
Joel
- JoelR asked 12 years ago
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BTW, the "Volume Adjustment" attribute in the SOX audio utility does exactly what I need:
"The "Volume Adjustment:" field in the statistics gives you the argument to the -v number which will make the sample as loud as possible without clipping."
Volume Adjustment is a scaling factor by which you could boost a given sample without clipping. So if you get a very low VA, like 1.05, it means your sample is 5% away from clipping. A VA of 100 would mean the sample is virtually silent and could be scaled 100x before clipping.
I used this command line utility to great effect in the past and am trying to replicate this functionality with FMOD. So far, I’m getting bogged down with analyzing the full spectrum rather than an overall "hotness" of the signal. I feel like I’m approaching the problem incorrectly.
Thanks again,
Joel
I found the problem that was causing the volume measurement to give the same result each time–my loop to call the volume measurement every 10ms for 1 second wasn’t updating the actual measurement so it was averaging the save value 100x. Turns out the first portion of my recordings are the same volume every time.
I’d still like to know if there’s a easier way to measure the "hotness" of a recorded signal.
Joel | http://www.fmod.org/questions/question/forum-19922/ | CC-MAIN-2018-34 | refinedweb | 598 | 56.86 |
Statistics collection on dungeon generation. More...
#include "math.h"
#include "angband.h"
#include "cave.h"
#include "cmds.h"
#include "effects.h"
#include "game-input.h"
#include "generate.h"
#include "init.h"
#include "mon-make.h"
#include "monster.h"
#include "obj-pile.h"
#include "obj-randart.h"
#include "obj-tval.h"
#include "obj-util.h"
#include "object.h"
#include "ui-command.h"
#include "wizard.h"
Statistics collection on dungeon generation.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
The stats programs here will provide information on the dungeon, the monsters in it, and the items that they drop.
Statistics are gotten from a given level by generating a new level, collecting all the items (noting if they were generated in a vault). Then all non-unique monsters are killed and their stats are tracked. The items from these monster drops are then collected and analyzed. Lastly, all unique monsters are killed, and their drops are analyzed. In this way, it is possible to separate unique drops and normal monster drops.
There are two options for simulating the entirety of the dungeon. There is a "diving" option that begins each level with all artifacts and uniques available; and there is a "level-clearing" option that simulates all 100 levels of the dungeon, removing artifacts and uniques as they are discovered/killed. "diving" option only catalogues every 5 levels.
At the end of the "level-clearing" log file, extra post-processing is done to find the mean and standard deviation for the level you are likely to first gain an item with a key resistance or item.
In addition to these sims there is a shorter sim that tests for dungeon connectivity.
Referenced by get_debug_command(). | http://buildbot.rephial.org/builds/restruct/doc/wiz-stats_8c.html | CC-MAIN-2018-26 | refinedweb | 295 | 62.44 |
Important: Please read the Qt Code of Conduct -
Code suddenly stops at self.cam = QCamera() , PyQt5.9.2, Qt5.9.3, Python3.5
Hello,
I am working on Ubuntu Mate with an Raspberry Pi 3.) if __name__ == '__main__': app = QtWidgets.QApplication(sys.argv) cam = Camera() sys.exit(app.exec_())
I tested how far the compiler runs and it just stops at self.cam = QCamera(). No error, nothing. I dont know what could be wrong with something simple like QCamera(). Anyone got an idea?
Greets,
Xenoshell
Hi,
How do you know it stopped ?
From the looks of it, you don't call show on anything so if you are expecting a GUI, you should at least show the
QCameraViewfinder.
Oh well hello @SGaist,
I am just trying some stuff. My full code is here:() print(_())
I just wanted to show the "important" part. But yeah it basically prints 1 then 2 and not 3 so it obviously just stops there. No error message or anything like that. It just gets stuck
Just to make absolutely sure it's the
QCamera(), could you put a
print("2.5")after the
super()line and before the
QCamera()line, please?
Also, although doubtless it won't make any difference, have you at least tried one of the other
QCamera()constructors which take an argument instead, e.g.
QCamera(QCamera.FrontFaceor
QCamera.UnspecifiedPosition)?
This is how it looks now. I tried using QCamera(QCamera::Position position, QObject *parent = Q_NULLPTR) with position = 0 which means default. How would i initalise the other constructors? i would have to check the devicename or the camerainfo before actually initialising the camera. Is that even possible?
def __init__(self, parent = QObject()): super(Camera, self).__init__(parent) print("3") self.cam = QCamera)
Could it be that i am missing a repository and i need to install something?
Did you try to just list the camera available on your system ?
Write the python equivalent of:
QList<QCameraInfo> cameras = QCameraInfo::availableCameras(); foreach (const QCameraInfo &cameraInfo, cameras) { qDebug() << cameraInfo.deviceName(); }
Ok, somehow when i use
sudo python3 qt5.pyinstead of
python3 qt5.pythe program doesnt stop at
self.cam = QCamera(). I suspect this is just something with ubuntu mate.
The bad part about this is that the camera window opens for a second and then my whole screen goes black. On the top left side is a underscore that blinks, then my raspberry is locked and i need to type in my password again.
It almost looks like the terminal is going fullscreen but thats just my guess.
Also the output for
qcamerainfo.availablecameras()is
PyQt5.QtMultimedia.QCameraInfo object at 0x72dbe3b0so i guess i could write
QCamera(0x72dbe3b0)?
Greets,
Xenoshell
@Xenoshell I guess the user you're using on your Ubuntu system does not have access rights to the camera device. You need to check the group of the camera device and add your user to that group.
Is that really the problem if i can just use sudo? I am more worried about the screen just going blank. Can you maybe recommend a good debuggin program? I use geany but it doesnt even has a step option and eclipse is very complicated to set up with python or i just didnt managed to link all the libraries
Oh i just ran
gdb python3just to see the error and if it would give more informations. This was the output:
Program received signal SIGSEGV, Segmentation fault. 0x76fd9dde in ?? () from /lib/ld-linux-armhf.so.3 (gdb) bt #0 0x76fd9dde in ?? () from /lib/ld-linux-armhf.so.3 #1 0x76fd9df6 in ?? () from /lib/ld-linux-armhf.so.3 Backtrace stopped: previous frame identical to this frame (corrupt stack?)
So it seems like i have also a segmentation fault with ubuntu mate. I also tried the same program with raspbian and i also got a segmentation fault. The only difference is that it is now another file that gets called.
Is that really the problem if i can just use sudo?
You really should not run your application as root just to get around this issue! If you expect non-root users to access your camera, you need to set whatever Linux permissions are necessary to allow them access to it.
gdb python
But you run your application via
python3, so there's no point trying to debug
python, which under Linux is Python 2.... You need to run
gdb python3, and then type
run qt5.py....
The issue with python or python3 was a typo on my part so all the outputs are with python3. If my code is finished i actually planned to put it on autostart so the raspberry pi can only be used as a camera with also some other functions. What should i do if i wanna fix this issue with sudo?
@jsulm said in Code suddenly stops at self.cam = QCamera() , PyQt5.9.2, Qt5.9.3, Python3.5:
@Xenoshell I guess the user you're using on your Ubuntu system does not have access rights to the camera device. You need to check the group of the camera device and add your user to that group.
What have you done about about what @jsulm suggested?
@JNBarchan What group are you talking about? I am pretty new in python programming or general speaking ubuntu so i dont know how to check the group of the camera device and add me to that group. I set up this Ubuntu Mate myself and i am the only user on the Raspberry Pi besides root
@Xenoshell
Sorry, I know nothing about "camera device access/groups under Ubuntu" other than what @jsulm wrote. (I use Ubuntu, but not Mate/Pi, and I don't have a camera.) He may return to offer more information, or he may just be giving you a hint as to what you need to look for.
If you're new to Ubuntu/Linux, here's just a word about
sudo/root user.
- Linux (like Windows) has users & groups, who have different permissions. Files and devices have permissions, and if your user/groups doesn't have permission to access something you'll be blocked from it.
- Ubuntu doesn't really have a
rootuser that you can log in as, per se, but you can use the
sudocommand to gain root privileges.
- You are saying that if you run your code normally as you, it "hangs" at
QCamera().
- But if you run it as root via
sudoit does not hang.
- That would imply you as you lack permission to access the camera (perhaps a device), while root does not have that problem.
- Therefore we are thinking there might be a "group" who have access to the camera, and you need to be a member of that group.
- You can list all groups with
cat /etc/groups. You'd have to look through yours to see if there looks like anything "likely". You add users to groups via
adduseruser group.
- You can run
sudo python3 qt5.pyif you really want. But it's a really bad idea (haven't got time to list myriad reasons), and I think you'll really regret it as you try to do other stuff in your app.
BTW, did you have to install your "camera device/software"? If so did it come with any instructions about this?
Your Python code looks OK, and I doubt it will have anything to do with Python/PyQt.
I am a little surprised that just plain
QCamera()hangs/requires permissions, because you're not even naming a device there, but it might do, or it might try to access the "default" camera device, i don't know. @jsulm / @SGaist know more than me.
Try @SGaist's suggestion of just enumerating the available cameras. You're going to need to learn soon how to turn his bit of Qt C++ code into Python to get anywhere much with Qt.... (Not meaning to be rude or disheartening, just a heads-up, but if you think you could just write code
QCamera(0x72dbe3b0)in Python or C++ you have quite a bit still to learn before you'll be able to do stuff.)
Finally, I don't like the look of
gdb python3itself generating a SIGSEGV, but I don't know exactly what you did, could be a red-herring.
Your "screen going black and locking up" might be to do with it requesting a password to access, I really don't know. I assume you've got your camera all working and you can play with it OK outside of your application?
@Xenoshell Please take a look at
Each device is represented by a device file which. To read from such a device you read from the device file to write to the device you write into this file. UNIX/Linux access rights apply to device files as well. So, you have user, user groups and others. You have read/write and execute rights. My guess is that the user you are using on your machine does not have access rights to the camera device file. Usually to solve this you just need to add this user to the correct user group (probably this group is called "video"). To see in which groups your user is member execute the command "groups" in a terminal. To add a user to a group see
@JNBarchan
- input: cat /etc/group -> output (i am in the group video)
I just post this if i dont see a group i should be in:
root:x:0: daemon:x:1: bin:x:2: sys:x:3: adm:x:4:syslog,blz tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: uucp:x:10: man:x:12: proxy:x:13: kmem:x:15: dialout:x:20: fax:x:21: voice:x:22: cdrom:x:24:blz floppy:x:25: tape:x:26: sudo:x:27:blz audio:x:29:pulse,blz dip:x:30:blz www-data:x:33: backup:x:34: operator:x:37: list:x:38: irc:x:39: src:x:40: gnats:x:41: shadow:x:42: utmp:x:43: video:x:44:blz sasl:x:45: plugdev:x:46:blz staff:x:50: games:x:60: users:x:100: nogroup:x:65534: systemd-journal:x:101: systemd-timesync:x:102: systemd-network:x:103: systemd-resolve:x:104: systemd-bus-proxy:x:105: input:x:106:blz crontab:x:107: syslog:x:108: netdev:x:109: messagebus:x:110: uuidd:x:111: mlocate:x:112: ssh:x:113: ssl-cert:x:114: lpadmin:x:115:blz lightdm:x:116: nopasswdlogin:x:117: ntp:x:118: avahi-autoipd:x:119: avahi:x:120: bluetooth:x:121: scanner:x:122:saned colord:x:123: pulse:x:124: pulse-access:x:125: rtkit:x:126: saned:x:127: whoopsie:x:128: gpio:x:999:blz i2c:x:998:blz spi:x:997:blz blz:x:1000: sambashare:x:129:blz
QCamera(0x72dbe3b0)
From the QCamera documentation: "QCamera::QCamera(const QByteArray &deviceName, QObject *parent = Q_NULLPTR) Construct a QCamera from deviceName and parent."
Correct me if i'm wrong but that means if i know the deviceName that i can just initialize the Camera with QCamera(0x72dbe3b0).
3)
gdb is a debug program which can be used for segmentation fault errors.
ls -l /home/blz/Schreibtisch/qt5.py
Output:
-rwxrwxrwx 1 blz blz 1537 Dez 7 10:33 /home/blz/Schreibtisch/qt5.py
I guess that means that i have full accessibility to qt5.py
Thanks for your help. I appreciate your feedback.
Greets
- jsulm Qt Champions 2019 last edited by jsulm
@Xenoshell 1. Well, the question is: what is the group of the camera device file?
2. You can use this code to see all the camera device names ():
QList<QCameraInfo> cameras = QCameraInfo::availableCameras(); foreach (const QCameraInfo &cameraInfo, cameras) { qDebug() << cameraInfo.deviceName(); }
- Yes, you can use GDB to get more information if your app crashes
- Everyone has full access to Schreibtisch/qt5.py. Not sure how is this related?
Nothing looks interesting in your groups. Never mind, it was only an idea of @jsulm's, maybe or maybe not relevant.
Correct me if i'm wrong but that means if i know the deviceName that i can just initialize the Camera with QCamera(0x72dbe3b0).
It's so wrong. Fortunately in C++ it won't compile, in Python I hope it will spit it back at you. You really need to understand why this is plain wrong in any language/circumstance, if you're new to programming. You must pass a string which has the value of a device name to
QCamera(), e.g.
QCamera("camera-device-name"), or a device name picked up from a
QCameraInfo.deviceName()(which itself is a string).
Please try @jsulm's suggestion of enumerating the available cameras you have. In Python it'll be like:
for cameraInfo in QCameraInfo.availableCameras(): print(cameraInfo.deviceName())
QString QCameraInfo::deviceName() const
Returns the device name of the camera
This is a unique ID to identify the camera and may not be human-readable.
So a device name might come out like
abc1234(I don't know 'coz I haven't got one to test). Then the actual Linux device will be
/dev/abc1234, or something like that. We want you to
ls -lthat, and look at its owner & group permissions, and see if you have access to it under your own user, not
sudo. This is what we mean about "permissions", not the permissions you list for
/home/blz/Schreibtisch/qt5.py.
@JNBarchan, @jsulm
The output for the for-loop is:
/dev/video0
Here the output is:
blz@blz-desktop:~$ ls -l /dev/video0 crw-rw----+ 1 root video 81, 0 Dez 11 10:55 /dev/video0
To me it looks like i dont have the permission to everything.
@Xenoshell Add yourself to the video group if it's not already the case
@Xenoshell
You can see if you're already a member of
videogroup via executing command
groups.
If your username is
blz, I think you already are....
If you are a member, it would then look like: as yourself, not root, you do have access to the camera device, hence you say it seems to "initially open", but then something else is happening which works as
rootbut not as you.... You could temporarily
sudo chmod 666 /dev/video0, see if that helps, then revert to
sudo chmod 660 /dev/video0.
@jsulm @JNBarchan ,
i am already member of the video group.
The camera device only opens if i use sudo. If i dont it just gets stuck at self.cam = QCamera().
After the command
sudo chmod 666 /dev/video0i tried using qt5.py without sudo but it just got stuck.
So there has to be a group which i am not a member of that uses QCamera(). Am i at least right with this assumption?
Ok i cant reproduce the gdb output anymore. It just stops at 1 and then somehow locks up and i have to relog again.
I somehow have this feeling that the code/the usb-camera use audio or at least try to use it. When i want to turn off the pi i always get the message that "Pulse Audio Sound System" is currently running and if i want to terminate it.
Tomorrow i will sit down and try to get the gdb output without sudo /with sudo and look what is possible.
Debugging can really be stressful...
@jsulm, @JNBarchan
Here i am again, this is the new gdb output:
(gdb) run qt5.py Starting program: /usr/bin/python3 qt5.py Cannot parse expression `.L1185 4@r4'. warning: Probes-based dynamic linker interface failed. Reverting to original interface. [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1". 1 [New Thread 0x72b39470 (LWP 4134)] 2 3 [New Thread 0x6de10470 (LWP 4139)] [Thread 0x6de10470 (LWP 4139) exited] [New Thread 0x6de10470 (LWP 4140)] [Thread 0x6de10470 (LWP 4140) exited]
At this output is libpulse.so and also libasound.so.2 i talked about in my post above. It could actually be that QCamera() tries to also initalise Audio but obviously i dont have any audiooutput plugged in and thats why it stops at QCamera
(gdb) bt #0 __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 #1 0x76f21c0a in __GI_ppoll (fds=0x7001a8, nfds=1, timeout=<optimized out>, sigmask=0x0) at ../sysdeps/unix/sysv/linux/ppoll.c:50 #2 0x73389e12 in pa_mainloop_poll () from /usr/lib/arm-linux-gnueabihf/libpulse.so.0 #3 0x7338a290 in pa_mainloop_iterate () from /usr/lib/arm-linux-gnueabihf/libpulse.so.0 #4 0x6de2888c in conf_pulse_hook_load_if_running () from /usr/lib/arm-linux-gnueabihf/alsa-lib/libasound_module_conf_pulse.so #5 0x6e01c9f2 in ?? () from /usr/lib/arm-linux-gnueabihf/libasound.so.2 Backtrace stopped: previous frame identical to this frame (corrupt stack?)
Here the info threads:
(gdb) info threads Id Target Id Frame * 1 Thread 0x76ff6300 (LWP 4204) "python3" __libc_do_syscall () at ../sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:46 2 Thread 0x72b39470 (LWP 4206) "QXcbEventReader" 0x76f21b90 in poll () at ../sysdeps/unix/syscall-template.S:84
Can anyone tell me whats going on in those gdb outputs? Are they even important or are they just there and we cant really do anything with them?
@Xenoshell
Because you are using Python, not a standalone executable of your program compiled from C++, if you use
gdbyou have to
gdbthe Python executable, not your app running as a Python script. This means
gdbprobably is not of any interest to you, per se, for general debugging of your app; though it may give us some clues in this particular case.
To clarify, for your app script completely. Just run
gdbagainst Python without any mention of your
qt5.pyscript. For the record, here is my output under Ubuntu not Pi:
jon@ubuntu:~$ gdb python3 Reading symbols from python3...(no debugging symbols found)...done. (gdb) run Starting program: /usr/bin/python3 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Python 3.5.3 (default, Nov 23 2017, 11:34:05) [GCC 6.3.0 20170406] on linux Type "help", "copyright", "credits" or "license" for more information. >>>
Does yours produce much the same? Does it only give the
libpulse/
libasoundif a certain line is in your Python script, and not if it is removed, then you'd have an idea what is related to what? I wish you'd show what that line is now, because we no longer know whether you are enumerating available cameras or opening a camera?
@JNBarchan
This is the whole output:
blz@blz-desktop:~$ gdb python3 GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) python3...Reading symbols from /usr/lib/debug/.build-id/d7/14ad8d8b52ca34a8a81f10b4917027977b05ca.debug...done. done. (gdb) run Starting program: /usr/bin/python3 Cannot parse expression `.L1185 4@r4'. warning: Probes-based dynamic linker interface failed. Reverting to original interface. [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1". Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609] on linux Type "help", "copyright", "credits" or "license" for more information. >>>
My code always stops at self.cam = QCamera() otherwise it would also print 4 and not suddenly stop
As a reminder,) print("3") self.cam = QCamera() print(()) for caminfo in QCameraInfo.availableCameras(): print(caminfo.deviceName())_())
@Xenoshell
I asked earlier:
Does it only give the libpulse/libasound if a certain line is in your Python script, and not if it is removed, then you'd have an idea what is related to what?
So, if I were you, under
gdb, I'd try commenting in & commenting out the
QCamera()line, and report whether your debugger only shows the
libpulseerror if & only if you have that line in there. then you'd know for sure whether
QCamera()has anything to do with
libpulse....
I'd also try
QCamera("video0")or
QCamera("/dev/video0")or whatever it is, instead of plain
QCamera(). I'd probably also try
QCamera("rubbish"). These are all things for you to play with to try to understand just what causes the problem/hang, it's up to you....
@JNBarchan
I commented
QCamera()and obviously i also need to comment the stuff that is in correlation to
self.cambecause otherwise i would get a simple error because
self.camis not there. Then i also dont get the libpulse error, well tbh there is not much to compile because about half the code is commented.
I tried using
QCamera("/dev/video0)and also video0, this results in the error:
TypeError: arguments did not match any overloaded call: QCamera(QObject parent=None): argument 1 has unexpected type 'str' QCamera(QByteArray, QObject parent=None): argument 1 has unexpected type 'str' QCamera(QCameraInfo, QObject parent=None): argument 1 has unexpected type 'str' QCamera(QCamera.Position, QObject parent=None): argument 1 has unexpected type 'str'
I can follow you that this should be right but how are you supposed to initialize QCamera if you need the QCameraInfo or a QByteArray?
Are you supposed to initalize without anything -> find out the QByteArray -> initialize QCamera with the correct QByteArray?
Thanks again for your help
@Xenoshell
For the way to invoke
QCamera(), sorry, I misremembered the constructor, and thought it took a string. It takes a byte array of the name instead. From Python, you'll use
str.encode(), e.g.
"/dev/video0".encode().
Maybe it's not a good idea to try to create an "empty"
QCamera(). Try using a constructor which does take an actual camera. One of:
- `QCamera(QCameraInfo.defaultCamera())
QCamera("/dev/video0".encode())
- One of the available cameras returned by the loop:
for caminfo in QCameraInfo.availableCameras(): print(caminfo.deviceName()) acam = QCamera(caminfo)
I hope one of the above works instead of the default constructor. Maybe only root can create the empty one (though have to say I'm dubious)....
Now that I think I understand what your code is intending to do, I believe you always intended
QCamera(QCameraInfo.defaultCamera()). Don't forget the docs admonition:
QCameraInfo QCameraInfo::defaultCamera()
Returns the default camera on the system.
The returned object should be checked using isNull() before being used, in case there is no default camera or no cameras at all.
See also availableCameras().
@JNBarchan
well that didnt do anything... When i use
QCamera("/dev/video0".encode())or
QCamera(QCameraInfo.defaultCamera())it just prints till 3 and then stops.
Maybe i need to add myself to the audio group (EDIT: ok already am)
@Xenoshell
Then at this point I'm afraid I'm stumped.
QCamera(QCameraInfo.defaultCamera())should definitely not hang. I don't know what is going on in the Qt code which will cause something to do so unless run as root. (I just wonder whether something might be prompting for, say, root password to allow access, and that's why it hangs/goes black....)
You need one of the experts who knows what the Qt code does to get you anywhere now, I think....
@JNBarchan
No worries, i think it should work too and am baffled... Maybe i can summon @Lifetime-Qt-Champion @SGaist ? He has also helped me alot in the past. But i am quite sure it has something to do with the gdb output
You can't without lots of chocolate...
Minimal PyQt5 example that shows a viewfinder using the default camera:
import sys from PyQt5.QtWidgets import QApplication from PyQt5.QtMultimedia import QCamera, QCameraInfo from PyQt5.QtMultimediaWidgets import QCameraViewfinder if __name__ == '__main__': app = QApplication(sys.argv) camera = QCamera(QCameraInfo.defaultCamera()); viewfinder = QCameraViewfinder() viewfinder.show() camera.setViewfinder(viewfinder); camera.start() sys.exit(app.exec_())
Does it work for you ?
@SGaist
Nope doesnt work. Its the same thing. Without sudo it doesnt do anything and with sudo it just locks up and i have to login again. I cant find a reason why the raspberry pi just locks up. For me thats the strangest thing to happen. I had my code once on Raspbian but now i am on Ubuntu Mate since i always got a segmentation fault on Raspbian.
@SGaist
We have established that for the OP
QCamera(QCameraInfo.defaultCamera())--- or indeed
QCamera(anything-at-all-or-nothing
)--- hangs unless he runs it via
sudo. (The only thing I don't think he has clarified is whether
QCamera("nosuchcamera".decode())succeeds returning an invalid camera object or also hangs --- but I suspect the latter.)
What would be nice to know from an expert is: from the Qt source code, what does just a minimal
QCamera()constructor actually do? It seems to invoke something in the OS/multimedia --- perhaps something which requires a permission --- but what??
@Xenoshell
Hmm, have a look at new post which has arrived:
This confirms your suspicion that
libpulsehas something to do with cameras and perhaps
QCamera. I don't know what to tell you to do about it, but maybe check what you have installed in that light (
libpulse&
libpulse-dev)?
@JNBarchan
I knew it! Sadly installing libpulse-dev did nothing for my problem. Everything stays the same.
Does that mean that maybe my installation of Qt5 or PyQt5 is faulted? I know that i didnt managed to install PyQt5/Qt5 with the QtMultimedia because somehow the command didnt work and i then just used the repository to get qtmultimedia
EDIT: i just checked the groups again and if something strikes my eye. I saw that i am not in the pulse and pulse-access group. I dont think its gonna do anything, though.
@Xenoshell
Well it's possible (it would only be your Qt installation, not your PyQt). I don't know how you went about it, as I only fetch from Ubuntu repositories (
apt-get) for all things Qt, never from Qt themselves. If you're saying you did a "max-and-match" --- some things one way, some another --- you might not have a consistent/correctly located set of libraries. You might want to clarify what you mean by:
i didnt managed to install PyQt5/Qt5 with the QtMultimedia because somehow the command didnt work and i then just used the repository to get qtmultimedia
as anything which "didn't work" in this area could be a clue....
However, this would be implicated if your code always "hung". But the fact that it does work as root but not as you makes one assume that your installation does work.
Deffo think you should post here your problems/try again with anything which "did not work right" during install, especially if it's to do with multimedia....
@JNBarchan
Well i wanted to install Qt5 from source but in the default installation is not QtMultimedia. So i wanted to use the command to install also QtMultimedia but somehow the command didnt get recognized so i just didnt install QtMulti from source but installed it with a repository. The help command didnt do much for using the correct command, because im quite sure i can read.
@Xenoshell
Look, I don't know your situation, but maybe it's possible that your multimedia is "out of sync" with the rest of your Qt installed? Like I said, I'm surprised then that it works for root but not other users, but who knows....
Since no-one else seems to be posting to help you on your camera issue, you might want to try a new thread purely about how to correctly install Qt with multimedia under your OS, get it all sorted out properly, and then see if miraculously that solves your problem.... | https://forum.qt.io/topic/85682/code-suddenly-stops-at-self-cam-qcamera-pyqt5-9-2-qt5-9-3-python3-5/19 | CC-MAIN-2020-34 | refinedweb | 4,598 | 64.91 |
CSS tutorial
Contents
- 1 Introduction
- 2 Cascading Style Sheets principles
- 3 Associating styles with HTML
- 4 CSS woes
- 5 The HTML div and span elements
- 6 Introduction to CSS 2 selectors
- 6.1 Simple selectors for HTML elements
- 6.2 The universal default selector
- 6.3 Children, cousins and other family
- 6.4 Selection of elements through their attributes
- 6.5 Class selectors
- 6.6 The ID selector
- 6.7 Cascading and inheritance
- 6.8 Pseudo classes and pseudo elements
- 6.9 Summary of CSS2 selectors
- 7 CSS properties
- 8 Printing with style
- 9 If your stylesheet doesn’t display as it should
- 10 Tools for CSS editing
- 11 Resources on the web
1 Introduction
- Learning goals
- Understand the structure of cascading stylesheet (CSS) rules
- Learn how to include CSS in HTML files and/or how to associate a CSS file with HTML
- Understand how to use moderatly complex selectors
- Learn how to style text elements
- Deal with different media (and browers)
- Be able to find CSS documentation (selectors, properties, compatibility tables)
- Prerequisites
- Basic HTML, e.g. the HTML and XHTML elements and attributes tutorial
- More detailed tutorials
- Computer colors tutorial
- CSS text styling tutorial
- CSS color and background tutorial
- Font readability
- CSS media and alternative style sheets tutorial
- CSS for print tutorial
- CSS box model tutorial
- CSS float tutorial
- CSS positioning tutorial
- CSS transforms tutorial
- CSS for XML tutorial
- CSS compatibility
- Analyzing CSS tutorial
- DHTML
- Level and target population
- Beginners
- Remarks
- This tutorial is intended for students in educational technology or any other field that is technology intensive and presents an overview of CSS. For people who need less, there exist many easy CSS tutorials on the web. This text is intended for students who also must learn principles and who are willing to learn more CSS by looking at CSS code and online reference manuals. Ideally, a teacher also should introduce CSS through hands-on lab activities (after, during or before assigning this tutorial for reading). Also, some topics are explored in more depth in other CSS tutorials and articles
- This a first version - It needs some work - Daniel K. Schneider 19:26, 8 September 2009 (UTC).
- In any case, this tutorial is not a reference manual and will never be. Therefore, you also must adopt at some point some on-line reference (see out pointers at the bottom), buy a CSS book or learn how to read the specifications.
- Some of the contents will not print well in PDF (lack of CSS 3 support of the PDF rendering extension / sept 2009
The executive summary
A CSS Style sheet is set of rules that describe how to render (X)HTML or XML elements. In essenence, HTML defines the content structure of a page and CSS defines how contents should be displayed (and sometimes at which position)
Each CSS rule has two parts:
- The selector: defines which elements are styled with this rule
- The declaration: defines rendering (the looks of these elements). Technically speaking, it defines values for various style properties.
Here is a simple example with two CSS rules for HTML:
P { font-face: Verdana, sans-serif; font-size: 12pt; } H1, H2, H3 { color: green; }
As we shall see later, the first rule defines that <P> should use a 12pt Verdana font (or a default sans-serif font, if Verdana is not available on the system). The second rules states that all H1, H2 and H3 titles should be green.
Usually, CSS rules are defined in a separate file which then is associated with the HTML file. This way one can reuse one stylesheet for many different HTML pages.
2 Cascading Style Sheets principles
Purpose of CSS and status of the CSS 2 implementation
Today, CSS has three related main purposes
- Define rendering of HTML and (text-centric) XML elements
- Define page layouts
- Support for interactive and animated pages, e.g. CSS3 animations, dynamic HTML (DHTML), or dynamic SVG. More precisely, either pure CSS3 or JavaScript programs can alter CSS properties of HTML elements in order to move them, change their shape or have them appear/disappear, etc. Animation is about changing properties of objects over time, and there are different technologies to do so.
Advantage of using CSS for styling web pages
CSS is the modern way to define HTML styles (including positioning of elements in the page). Older HTML dialects include special tags for styling, i.e. the <font> tag, but their use is now strongly discouraged.
- The Separation of content and style makes web sites easier to maintain
- CSS allows for multiple rendering of the same contents, i.e. adaptation to media and people (screen size, font size, print, etc.)
- In addition, CSS can be used to render contents of any text-centric XML vocabulary, e.g. one that you could invent on the fly (see the CSS for XML tutorial).
Disadvantages and problems of CSS
The lack of text-transformation in CSS1/CSS2 makes CSS rather unsuitable for data-centric XML or long HTML "articles" (e.g. you can't automatically create a table of contents).
Implementation of CSS 2 was bad in IE 6 / 7, i.e. there were several bugs and in addition some selectors and properties were not implemented. For example IE 6/7 did not implement the content property which would be needed to display attribute values and/or to add extra text to output. CSS 2 support is better in IE8, however CSS 2.1 is not yet fully implemented. Other browsers have a better track record in supporting standards, but none is totally perfect (although some claim to be).
Implementation history
- CSS 1 (1996): Worked ok in Firefox 1.x / Opera and more or less OK in IE 6
- CSS 2 (1998, revised 2008): Worked more or less ok in Firefox 2.x/Opera, well in Firefox 3.x, not too good in IE 6/7, well in IE8.
- CSS 2.1 (2009). As of Sept. 2009, implemented in the latest versions of most browsers. However, as of summer 2010, there are some remaining issues. Please, consult a a compatibility table, e.g. Quirksmode.
- CSS 3 (under construction). As of 2014 most features already are implemented in several browsers, but most often through vendor-specific tags.
Hint: Use browser compatibility tables when you plan for a larger audience
Syntax of CSS declarations
A style sheet is a set of rules (also called rule sets) that describe how to render XML or HTML elements. Each rule has two parts:
- The selector (before the curly braces) defines to which elements a rule applies
- The declaration block (inside the curly braces) defines rendering, i.e. values of CSS properties
The syntax can be summarized as follows:
selector { property:value; property:value; .... }
- Each declaration block includes at least a property name and a value, separated by a colon (:)
- Each property:value pair must be separated by a semi-colon (;)
Here is a CSS for HTML or XHTML example:pt; font-weight: Bold; font-family: Times; }
As you can see h1 is defined more than once and the ground rule is that the last definition will apply, e.g. in our example, h1 will be blue.
CSS comments syntax
In computer speak, comments are lines of code that (usually) are ignored by the computer. Coders use comments to document the code in order to communicate and/or to remember what it does. In CSS, comments are inserted between
/* .... */ and may extend over several lines. But don't use comments within the braces of the property declaration.
Here is CSS example that includes two comments:
/* I love HUGE titles */ h1 {size: 50px ; } para {display:block;} /* para elements are blocks */
3 Associating styles with HTML
There exist three main methods for associating style with HTML:
- Use one ore more external CSS files and the HTML <link> tag.
- Use the HTML style tag. (also called page level styling)
- Use the HTML style attribute (also called inline styling)
You also can combine all three methods. In that case, inline styling has priority over page level styling over external styling for the same kind of rule (more about this cascading principle later).
3.1 Associating external CSS files with an HTML file
The CSS file is associated using the HTML link element. In the most simple case, we need to define three attributes:
- rel defines the type of file. Its value normally is "stylesheet"
- href defines the link to the URL of the CSS file
- type defines the kind of stylesheet. For CSS you must use "text/css".
This link element must be included in the head section of an (X)HTML file.
Here is a simple example:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en"> <head> <meta http- <title>Just So Stories, by Rudyard Kipling</title> <link rel="stylesheet" href="just-so-stories.css" type="text/css"> </head> <body> ..... </body> </html>
The file css-intro.css sits in the same directory as the HTML file.
In the following example, the CSS file sits in a "sibling" directory.
<link rel="stylesheet" href="../styles/css-intro.css" type="text/css">
In the following example, the CSS file is define with an absolute local path. I.e. it sits on the same server.
<link rel="stylesheet" href="/lib/css/css-intro.css" type="text/css">
Definition of Mediatypes
The media attribute allows to define a stylesheet for a different medium, e.g. a printer
<link rel="stylesheet" href="css-intro-print.css" type="text/css" media="print"> <link rel="stylesheet" href="css-intro-print.css" type="text/css" media="handheld, tv">
See the section below on alternate stylesheets for more information about media types.
Use of multiple stylesheets
You may include several stylesheets. Typically, in portalware, several stylesheets are loaded. Each one defines rules for a given set of elements, i.e. default styles for the portal, followed by styles for various modules. Often, programmers also load default styles first and then load administrator-defined styles on top.
Example from Zikula:
<link rel="stylesheet" href="themes/TecfaBreeze/style/style.css" type="text/css" media="screen,projection" /> <link rel="stylesheet" href="modules/News/pnstyle/style.css" type="text/css" /> <link rel="stylesheet" href="javascript/style.css" type="text/css" />
Example from Moodle (styles are dynamically generated with PHP files):
<link rel="stylesheet" type="text/css" href="theme/standard/styles.php" /> <link rel="stylesheet" type="text/css" href="theme/standardblue/styles.php" />
3.2 Importing style sheet files within a CSS file
To import a CSS file within another CSS file or the script element (page level styling) you may use a so-called at-rule.
@import url (base.css);
Important: These at-rules must be defined on top of a CSS file or HTML style element, i.e. before you define any CSS rule. Also, some at-rules are buggy in IE 6/7.
These at rules can be used for other purposes, e.g. to specify that one or more rule sets in a style sheet will apply only to certain media types (see below)
3.3 Style definitions with the HTML style tag
CSS rules may be inserted within the HTML STYLE tag (it must be in lower case in XHTML). Generally speaking, you should avoid this method because if you define your CSS with an external file you can use it with many other HTML pages.
HTML code that is generated on the fly often includes style definitions at page level. But this programming practise also should be avoided, since it is better policy to include all stylesheets in a special directory structure from where the programs then can load them in. Personally, we only use page level styling for teaching purposes (since the CSS code sits next to HTML code) and in situations where were we only want to carry a single file, e.g. in collaborative HTML writing via email...
Example of a page level (or embedded) style definition in the head of an HTML5 file:
<!DOCTYPE html> <html> <head> <title>Simple CSS demo</title> <style type="text/css"> body {background: white; font-family: Arial, sans-serif;} H2 {color: blue;} /* will be overriden by an other rule below */ H2, H3 {font-family: Arial, sans-serif;} H2 {color: red; text-decoration: underline;} P.intro {color: blue; margin-left: 4em; margin-right: 2em;} .default {margin-left: 2em;} </style> </head> .....
In true XHTML (served as "application/xhtml+xml"), the contents of style must be inserted within a CDATA declaration. Otherwise, you will get an error when you validate your code.
<style type="text/css"><![CDATA[ body { .... } h1 .... ...... //]]></style>
XHTML is XML. Inside an XML tag, you can't have another markup language like CSS. Put simply, <![CDATA[ ... ]]> tells the XML parser not to look "inside". If you just use XHTML syntax but serve the file as HTML so that IE can understand it, the CDATA section is not needed.
3.4 Inline HTML style definitions
Inline HTML style definitions like page level style definitions should generally be avoided for the same reasons, i.e. maintenance costs and division of labor. Therefore - again - only use it for testing and demonstration purposes.
Most (or all?) HTML tags allow the use of a style attribute like in the following example. As you can see, there is neither a selector nor curly braces. For obvious reasons, you only will define property-value pairs separated by a semi-colon (;) if CSS is used inside an HTML element.
Example:
<p style="color:green;font-weight:bold;">Green fat grass</p>
3.5 Alternate stylesheets
You can define alternate stylesheets to meet various user preferences. Often, designers define different stylesheets for different media types. But nothing prevents you to design several different styles for the same medium...
The CSS 2.1 specification distinguishes the following media types
- all - suitable for all devices.
- braille - for braille tactile feedback devices.
- embossed - for paged braille printers.
- handheld - for handheld devices (typically small screen, limited bandwidth).
- print - for paged material and for documents viewed on screen in print preview mode.
- projection - for projected presentations, for example projectors.
- screen - primarily for color computer screens.
- speech - for speech synthesizers. Note: CSS2 had a similar media type called 'aural' # for this purpose.
- tty - for media using a fixed-pitch character grid (such as teletypes, terminals, or portable devices with limited display capabilities).
- tv - Intended for television-type devices (low resolution, color, limited-scrollability screens, sound available).
There exist three methods for defining alternative stylesheets:
(1) You may define alternative stylesheets, e.g. one that uses a bigger font for people with bad eyesight. Most browsers allow users to select from alternative stylesheets. E.g. in Firefox through the View->Page Style menu.
Now, these stylesheets have to be linked in a special way unless they are media specific. In the example below we define two stylesheets for the screen medium. The 2nd and 3rd are alternate stylesheets that the user can choose.
<link rel="stylesheet" type="text/css" media="screen" title="Default style" href="default.css" /> <link rel="alternate stylesheet" type="text/css" media="screen" title="Friendly fonts" href="friendly.css" /> <link rel="alternate stylesheet" type="text/css" media="screen" title="bigtype" href="big.css" />
In addition, you should provide JavaScript code that will allow the user to switch style (a typical user may not know how to do this manually). A older very popular and free example is available from AlistAPart. A simpler, more elegant more sophisticated 2004 version also exists.
(2) The @import at-rule allows to specify a media type, i.e. you may use this strategy to load various CSS variants from a single CSS file.
@import url(print-style.css) print;
Also, you often will find the @import CSS at-rule as replacement of the HTML link tag. E.g. the two following expressions are identical:
(1) Import a style-sheet with @import
<style type="text/css"> @import url(css-intro.css) </style>
(2) Import the normal way
<link rel="stylesheet" href="css-intro.css" type="text/css">
(3) Media-specific alternatives also can be defined within a single style sheet using the @media at-rule.
@media print { body { padding: 3cm; } @media screen, projection { body { padding: 1cm; } }
Read more in CSS media and alternative style sheets tutorial
4 CSS woes
Despite the global acceptance of CSS, it took many many years before CSS 2 (defined in 1998) worked reasonably well. E.g. it took Microsoft over 10 years to produce a CSS 2 compliant browser (IE 8). In the past, in particular in the late nineties, page styling was a nightmare. In the early 2000s, simple use of CSS just worked fine, but sophisticated designs didn't and web designers had to use various ugly tricks. Web designers who code sophisticated pixel-precise code for all browsers on the market still have to do this, but "normal" people now can quite safely ignore browser specific code. As of summer 2009, you just may avoid using CSS 2.1 and CSS 3 and stick to CSS 2.0.
An additional problem is that most browsers have different CSS modes. I.e. IE8 can behave like IE7 or Firefox 3 like Netscape. To make sure that browsers will use modern CSS, the strategy is fairly simple: Use correct detailed HTML declarations on top of your HTML files. Read on ...
4.1 Dealing with bad implementations
“Quirks mode and strict mode are the two "modes" modern browsers can use to interpret your CSS. [...]. [...] In other words, all browsers needed two modes: quirks mode for the old rules, strict mode for the standard. IE Mac was the first browser to implement the two modes, and IE Windows 6, Mozilla, Safari, and Opera followed suit. ” (Quirksmode.org, retrieved 19:26, 8 September 2009 (UTC)).
There are two strategies for dealing with compatibility issues:
- You just don't care and develop according to recent standards (e.g. academics can do this)
- You spend a few days documenting yourself making sure that you will not adopt strategies that will break in future browsers. Below we just provide a few hints. For more information read CSS compatibility
The ground rule for modern browsers is the following:
- Most doctype declarations will trigger "strict" mode in most browser. This is a sort of commonly accepted heuristic adopted by browser makers and definitely not standardized. DocTypes are not about style ...
- In addition, always close all tags (even if you work with HTML 4x transitional !)
Henri Sivonen provides a detailed explanation, plus an overview table that show what various browsers do with various doctype declarations. We shall just mention here that most of the following kinds of declarations will trigger "strict" or almost strict CSS in most browsers:
- All XHTML DTDs
- The HTML 5 declaration (<!DOCTYPE html>)
- HTML 4 declarations that include a URL
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" ""> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" ""> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" ""> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" ""> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
Checking the mode in your browser
- Firefox: use the command View/Page Info
- IE: type javascript:alert(document.compatMode)
So what DTD declaration should you use ?
- HTML5 (recommended as of 2015)
<!DOCTYPE html>
- Standard 4.01 HTML strict
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "">
- Transitional 4.01 HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "">
- XHTML 1.1 strict
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "">
- Alternatively, no DocType: XML doesn't need a DocType and the HTML version is defined in the namespace declaration
- XHTML transitional
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">
- Alternatively, no DocType: XML doesn't need a DocType and the HTML version is defined in the namespace declaration
Legacy Internet Explorer hacks
Since IE 6 and 7 were known for really faulty CSS implementations, you may use the following HTML comments to force IE to load a IE-specifc stylesheet. Sine IE 8 works just fine, we suggest that you simply ignore IE 6/7 problems (unless you will have to design a website for a very large audience). IE8 has four modes: IE 5.5 quirks mode, IE 7 standards mode, IE 8 almost standards mode and IE 8 standards mode. Understanding under which conditions IE falls into what mode is really complicated. According to Henri Sivonen uses doctype sniffing roughly like other browsers if you did not do anything of the above, i.e. if you own a "normal web site" and create "normal standards-compliant" pages you should do fine.
Another strategy that you see a lot when you look a computer generated pages (i.e. in portalware) is to use HTML conditional comments that only work in Explorer on Windows. You can read more at Quirksmode. Example that shows how to load specific stylesheets for specific IE versions.
<!--[if IE 7]> <link rel="stylesheet" type="text/css" href="theme/standard/styles_ie7.css" /> <![endif]--> <!--[if IE 6]> <link rel="stylesheet" type="text/css" href="theme/standard/styles_ie6.css" /> <![endif]-->
Have a look at the styles used by this wiki page. In Firefox 2 and 3 use menu View-> Page Source or type ctrl-U. In IE 8, right click or use the Page menu and then "View Source". You will see IE specific comments. Anyhow, I suggest not to adopt this kind of informal markup, unless you really do have trouble creating good looking contents for older IE browsers.
Read CSS compatibility if you must learn how to use CSS hacks, i.e. deal with all sorts of issues related to bad CSS implementations.
5 The HTML div and span elements
Lets recall from the HTML and XHTML elements and attributes tutorial that we may roughly distinguish between block and inline elements. Basically, block elements start on a new line (e.g. titles, paragraphs or lists) and inline elements are inserted on the same line (e.g. some bold text or a picture).
CSS designers often use two specific HTML elements to define "custom" blocks and inline regions:
- <div>...</div> allows to define a block (that most often includes a region of normal HTML block elements)
- <span>...</span> allows to define a region within a block element, e.g. a few words in a paragraph.
Since these two elements play a critical role in modern web page design, we shall introduce these two elements again with some short example code. In addition, we suggest to install the View Source Chart Firefox extension. It allows to display the block structure of a web site and to understand how the layout is done.
5.1 The div tag
You may look at the source of a Mediawiki page (e.g. a Wikipedia or EduTechWiki page) to understand how portals might the structure contents of a page (if you are reading this online, view the source of this page). Simplified, the "div structure" of a page looks like this:
<div id="globalWrapper"> <div id="column-content"> <div id="content"> <div id="bodyContent"> ... lots of other nested divs inside, e.g. <div class="printfooter"> </div> </div> </div> <div id="column-one"> ... lots of other nested divs inside, e.g. <div class='generated-sidebar portlet' id='p-navigation_and_help'> <h5>navigation and help</h5> <div class='pBody'> <ul> <li id="n-Mainpage"><a href="/en/Main_Page">Main Page</a></li> <li id="n-about"><a href="/en/EduTech_Wiki:About">About</a></li> <li id="n-Help"><a href="/en/Help:Contents">Help</a></li> ...... </ul> </div> </div> </div> </div> </div>
Those many "divs" allow to position and style each "box". E.g. all the boxes of the class "generated-sidebar portlets" are positioned to the left and the "pBody" class is used to render the contents of these little menu boxes, e.g. draw a border with a margin.
Now, to make it a bit simpler. If you plan to style a whole section of your HTML in a given way, e.g. make it blue, then just wrap a div tag around the elements that make up this section. But make sure to respect the HTML "boxes within boxes" principle.
Good:
<div class="intro"> <h2>Introduction</h2> <p>I am happy to introduce CSS now.</p> <p>CSS was introduced .... </p> </div> <h2>Next section</h2>
Bad (closing div sits inside an p tag)
<div class="intro"> <h2>Introduction</h2> <p>I am happy to introduce CSS now.</p> <p>CSS was introduced ....</div> </p> <h2>Next section</h2>
We shall see below how we then could render the whole "intro" region in blue for example.
Important notice to absolute beginners: Don't think that you must use divs each time you do some complex CSS like positioning. The div tag is like any other tag, except that it is legal to put it around any other set of tags. E.g. you could have h1 titles inside a div, but you can't do that with the very similar <p> tag.
5.2 The span tag
The span tag has the same function as the div tag inside a block element.
Here is a little example that shows how to use span with inline styling.
<p> <span style="font-weight:bold;">This article <i>or</i> section is a stub</span>. A stub is an entry that did not yet receive substantial attention .....</p>
6 Introduction to CSS 2 selectors
Let's recall that a selector identifies the element(s) that we want to style by defining property values. In other words, in order to style a given set of elements we must be able to identify these elements.
CSS 2 selectors work for HTML, XHTML and any text-centric XML (XML needs a navigator that supports at least partially CSS 2.0 and XML). Each of the following sections will introduce a class of CSS selectors and we shall start with the most simple one.
Note: While explaining selectors we also will use property:value definitions in order to make the examples a bit more interesting. Don't worry, if you don't understand all of these. Or if you do, just look up the property definion in an online reference manual.
6.1 Simple selectors for HTML elements
Selection of an element
- element
The following example, says that all dd (definition list elements) should be numbered.
dd { display: list-item; list-style-type: decimal; }
You may start learning CSS just by styling various HTML element names, e.g. you may decide to change the font of all title elements. Instead of styling just one kind of element you also may include a list of elements as the following example shows:
The following example states that all h1 to h4 title elements should use Arial.
h1,h2,h3,h4 {font-family: Arial;}
6.2 The universal default selector
The universal selector matches any element type. As we will see later you then can add pseudo-selector components to it.
universal selector
- *
The following example tells that by default all elements will use a 12pt Arial font.
* { font-family: Arial /* By default all fonts will be Arial */ font-size: 12px /* Make them big enough */ }
Warning: The universal selector doesn't work in IE 6. There may be problems in IE7. A work-around strategy is to style the html or the body element, but you also may encounter problems with that in some older browsers.
body { margin: 0; padding: 0; color: black; background-color: #003399; font: 11px/1.5 Verdana, sans-serif; }
6.3 Children, cousins and other family
You also may define styles according to the position within which they may be found within a a text. E.g. you may style differently a p element inside a li element than a "normal" p element as you can see in the example just below.
Selection of a child element
- mother_element > child_element
In the following example, a normal paragraph will have a line height of 1.5, but if the p is found withing an li, then line height will be 1.3.
p { line-height: 1.5 } li > p { line-height: 1.3 }
Selection of descendant element (child, great-child, etc.)
- mother_element element
Example:
li p { .... }
All p elements that sit somewhere at any level of nesting inside a li tag will be affected
Combinations
Example:
DIV OL>LI P
Selection of siblings (elements next to each other sharing the same parent)
- sister_element + sister_element
In this example H2 follows H1:
H1 + H2 { margin-top: -5mm }
6.4 Selection of elements through their attributes
Sometimes, one would like to discriminate elements according to their attribute use and/or attribute values.
selection of an element that has a certain attribute
- element[attribute]
The following example sets all <h1 font="..."> elements to color blue.
h1[font] { color: blue; }
Selection of an element that has an attribute with a given value
- element[attribute="value"]
The following example sets all <div class="draft"> elements to color red.
div [class="draft"] { color: red; }
selection of an element that has an attribute with a value in a space separated list
Example:
div[status~="draft"] { color: blue; }
This selector would for instance work with the following HTML code:
<div status ="draft ugly important">
but not with the following one:
<div status ="ugly-draft">
There exist even more sophisticated attribute selector tricks, but we since have shown you enough with respect to a beginners tutorial we shall just list a few examples. A more complete list can be found for example at W3S Schools
[class^=ex] { background-color:red; }/* Every element whose class starts with "ex" */ [class$=ple] { text-decoration: underline; }/* Elements whose classe ends with "ple" */ [class*=amp] { margin-left: 4em; }/* Elements whose class contains "amp" */
6.5 Class selectors
Frequently, designers define a class attribute value for various HTML elements in a text. Let's show this with an example. In the HTML fragment below, we use two p elements. The first is a normal paragraph. The second includes a class="draft" attribute and value.
<p>I now got over a decade of CSS experience and understand fairly well how CSS works and how it can be used</p> <p class="draft">But on the other hand I really don't care much about style</p>
The class selector
- .class_name
On the CSS side we now can render the second paragraph in a different way. E.g. we could define a rule like this to make it red:
p.draft { color: red; };
A class selector is just an abbreviation for the attribute selector introduced above. E.g. we could have written the same rule as:
p [class="draft"] { color: red; };
Now let's assume that we got other HTML elements with a class="draft" and we want them all to be red. In that case we just could use the following syntax:
.draft { color: red; };
Alternatively, this could have been written with the Universal selector spelled out:
*.draft { color: red; };
To summarize, a "." means that you are referring to given class, i.e. a set of elements that includes an attribute class="something_you_define".
- .cl_name_1
- .cl_name_2
- .cl_name_3
Classes with spaces
You may assign more than one class to an element using spaces between class names.
<p class = "problem">This text is no so good</p> <p class = "killed">This is removed text</p> <p class = "problem killed">This text is so bad that we should remove it</p> <p class = "problem killed embarrassing">This text should be killed and its hardly visible</p>
p.problem { color: red; }; p.killed { text-decoration: underline; } p.embarrassing { color: yellow; }
6.6 The ID selector
In SGML and XML and therefore in HTML and respectively XHTML, 'ID' attributes allow to uniquely define an element in a given page. An ID attribute is declared as ID in its document type definition (DTD) or similar. E.g.
- in HTML, the ID attribute is id or ID
- in XHTML, the ID attribute is id
- in your own XML, the ID attribute can be anything.
The ID selector is usually used for complex CSS layouts, in particular the positioning of boxes that include menus and other items that are not in the main flow of the text. Each of these boxes must be uniquely positioned and there have a unique identifier.
The ID selector
- #
Example:
#mainmenu { ..... }
E.g. for HTML code like this:
<div id="menubox"> ..... </div>
We could use CSS like that:
#menubox { padding:5px; margin: 0px 2px 2px 2px; color: #000; background-color: #ffc; border: dotted black 2px; }
See the CSS positioning tutorial for more details.
6.7 Cascading and inheritance
If several rules affect an element, there must be a rule ordering principle. In simple CSS, roughly speaking, the last rule found will win. : E.g. if you define text color in more than one place, the color: property found in the last rule encountered will be used. However, this principle is only true for rules that have the same complexity.
Additionally, you must understand that properties are inherited from parent elements. More precisely, child elements (that is elements that occur within other elements) usually inherit properties from the parent elements as the following example shows.
In the following HTML fragment h1 and p are child elements of a div.
<div> <h1>Here is a title</h1> <p>Here is a paragraph </p> </div>
Now, in the following CSS, the p element will be affected by the property rule for the div tag. It will use Arial font because its div parent uses Arial.
div {font-family:Arial} h1 {font-family:Helvetica} '''/* para will inherit font-family from div, i.e. Arial */'''
Cascading is a complex issue and professional web designers understand that Cascading refers to the fact the rendering properties of a single element and its attributes may "trickle down from many sources. Let's recall the basic principle:
- More than one rule may define properties of an element.
- Most CSS properties (but not all) of a parent element will be inherited by its children.
According to SitePoint's Cascade article (which at some point you might read in detail), the CSS cascade involves these four steps:
- For a given property, find all declarations that apply to a specific element, i.e. load all CSS files that are declared for a given media type
- Sort the declarations according to their levels of importance, and origins. Other than the HTML page, the user plus the navigator (user-agent) also can add stylesheets. E.g. if you install the Greasemonkey extension to Firefox, you may install JS client-scripts that can override the original CSS. Declarations are sorted in the following order (from lowest to highest priority):
- user agent declarations
- normal declarations in user style sheets
- normal declarations in author style sheets
- important declarations in author style sheets
- important declarations in user style sheets
- Sort declarations with the same level of importance and origin by selector specificity. Typically, inline element specifications have the highest specificity. I.e. if the default style of a paragraph is normal, then it is logical that a span defining a bold part has higher priority.
- Finally, if declarations have the same level of importance, origin, and specificity, sort them by the order in which they are specified; the last declaration wins.
Cascading can be very tricky, however this is not the case for the kinds of simple style sheet a beginner or myself would write ...
The important keyword
- By adding important! to a property, you can override default cascading rules
- The !important keyword (or statement) is placed at the end of the declaration before the semicolon.
Example
text-indent: 0em !important;
6.8 Pseudo classes and pseudo elements
Pseudo-classes relate to user interaction with the document. For example, they allow to specify what happens when the user clicks on a link or moves the mouse over an element. Web designers use these pseudo classes in two ways:
- to change the way links and visited links are rendered (not really recommended)
- to implement dynamic HTML pages with CSS, DOM and JavaScript
We will discuss pseudo classes in another tutorial. In the meantime, we just quote from the excellent Sitepoint online reference: “CSS1 introduced the :link, :visited, and :active pseudo-classes, but only for the HTML a element. These pseudo-classes represented the state of links—unvisited, visited, or currently being selected—in a web page document.”
Pseudo-elements identify virtual elements that are not really appearent in the HTML code such as the first line of a block or the first letter of a block.
Two popular pseudo elements are :first-letter and :first-line
- :first-line is the first line of an element
- :first-letter is the first character an element
- before and :after are CSS 2 elements and are explained in the CSS for XML tutorial
Here is an example that makes the first line of a p tag green and the first letter 5 times as big as the others:
P:first-letter { font-size: 500%; color: green } P:first-line { color: green }
Other very popular pseudo tags allow to style links, for example:
- a:hover styles the link when the user moves the mouse or another pointing device over the link
- a:visited styles links that have been visited by the user
6.9 Summary of CSS2 selectors
7 CSS properties
Let's recall the syntax of CSS property definitions:
: property:value; : property:value,alternative_value1,alternative_value2,...;
7.1 What can be styled ?
So what can be styled ? One way of superficially answering this questions is to look at the specification. CSS 2.1 includes the following chapters:
- 8 Box model (properties for defining borders and margins)
- 9 Visual formatting model (properties for positioning and display)
- 10 Visual formatting model details (as above)
- 11 Visual effects
- 12 Generated content, automatic numbering, and lists
- 13 Paged media
- 14 Colors and Backgrounds
- 15 Fonts
- 16 Text
- 17 Tables
Websites that produce manuals for end-users may organize things a bit differently. E.g. the exellent 1-page CSS 2 Cheat sheet from David Child includes the following sections:
- Positioning
- Dimensions
- Color/Background
- Text
- Fonts
- Boxes
- Tables
- Paging
- Interface
- Aural
- Miscellaneous
The excellent SitePoint CSS Reference (retrieved 09:49, 10 September 2009 (UTC)) includes:
- Box Properties
- Layout Properties
- List Properties
- Table Properties
- Color and Backgrounds
- Typographical Properties
- Generated Content
- User Interface Properties
- Paged Media Properties
In this tutorial we will just provide a very short overview of some important basic CSS properties, but no details. Have a look at the Manual links we provide in our CSS links entry.
Furthermore, we will introduce layout properties that are used to position elements in the CSS positioning tutorial and dicussion creation of interactive web pages in tutorials like DHTML
To conclude this short overview of CSS properties, we may mention that there are three increasingly complex ways of using CSS:
- Style text, e.g. fonts size and type, colors, margins and indentations (not very difficult)
- Position elements on a page, e.g. menu elements
- Create dynamic pages (animation of CSS properties with JavaScript and AJAX real-time webserver connectivy with the JavaScript XMLHttpRequest object)
7.2 Units / values
Before we start introducing some of these properties, let's talk about units, i.e. values that you can define for sizes, distances, colors and so forth. CSS units are fairly intuitive and good online CSS references usually specify what units you may use for what properties.
- Length
Most properties are defined in terms of a length or size. As a designer you can pick from several kinds of units.
Firstly, there exist a series of so-called relative units
- em refers to the current font width, typically the size of an "m"
- ex refers to the current font size height, typically the height on an "x"
- px refers to pixels (on a screen the smallest unit that can rendered, on a printer very complicated ...)
- Other relative units for fonts (only) include: xx-large (h1), x-large (h2), large, medium, small, x-small and xx-small.
Second, there exist absolute units, i.e. something that you may measure with a meter. These include "normal" and "typographic" units.
- mm
- cm
- in (for Americans)
- pt: Points are an old typographic measure. I suggest to use these only when you deal with Fonts, since you can "see" what a font of X pts leads to. In CSS, a pt is 4.23mm (or 1/6th of an inch)
- pc: A pica is another typographic measure, i.e. 1 Pica = 12 Points.
Using absolute units do not guarantee the same effect on all screens since computer screens have different density of points/inches.
Thirdly, you may use just a number in certain cases.
- number - E.g. for line-height, you may use 1.3 (means that there is 30% of empty space with respect to the 100% of the current line height.
Below a few examples:
h1 { margin: 0.5em } /* margin is half an "m" */ h1 { margin: 1ex } /* ex */ p { font-size: 12pt } /* p's use a 12pt font size */ h1 { font-size: 1.2em } /* h1 uses a 1.2 * "m" size with respect to the inherited default font size */ p { line-height: 1.2 } /* 120% of 'font-size' */
- Percentages
Percentages are very useful to defined distances and sizes with respect to an other item/element/box.
- n%, e.g. 50%, 150%, 0.5%
The means of what a percentage refers to, depends on the property.
body { margin-left:5%; margin-right:5%; } h2+p:first-letter { font-size: 200%; }
- Colors
There are two way of defining colors. Either by its name (but the official list only includes 17 colors) or by a so-called RGB value. The latter can be specified in four different ways as we shall show in the example below. The 17 pre-defined color names in CSS 2.1 are the following, according to the CSS 2.1 specification from which we made a screen shot:
Otherwise, you may choose from several RGB numerical colors specifications as the following example shows. The following example will set the color of a text:
em { color: #f00 } /* #rgb = Red-Green-Blue shortcut for rrggbb*/ em { color: #ff0000 } /* #rrggbb */ em { color: rgb(255,0,0) } em { color: rgb(100%, 0%, 0%) }
In order to set the background-color use something like:
em { background-color: #f00 } /* #rgb = Red-Green-Blue shortcut for rrggbb*/ em { background-color: #ff0000 } /* #rrggbb */ em { background-color: rgb(255,0,0) } em { background-color: rgb(100%, 0%, 0%) }
E.g. The following CSS code
<p style="background-color: #0000ff; color: #ffffff;"> Blue background and white foreground</p>
would show like this:
Blue background and white foreground
CSS 3 implements far more sophisticated color models. Read the CSS color tutorial and maybe computer colors tutorial article for a more detailed introduction.
- URLs
CSS uses URLs in several places, e.g. to load background pictures, icons, or other CSS stylesheets. You may include the url within quotes or not.
body { background: url("") } li { list-style: url() disc }
- Font names
Font names are both an easy and a difficult matter.
Firstly, you must understand that not all fonts are available on all systems. As we shall explain below, you always should make sure that there is a "universal" fall-back font if your preferred font isn't available. In other words, always specify a list of fonts, and not just a single one. Since font names can have spaces as in Times Roman, font names need to be separated by commas and surrounded with quotes.
- font name, font name, ....
Here is a sans serif example:
* { font-family: Calibri, Verdana, Arial, sans-serif; }
- Other keywords
A certain number of properties take keywords. Keywords 'are not enclosed withing "quotes". We already introduced color keywords as in
color:red.
An other example are the specification of borders. E.g the border-style property can be one of none hidden dotted dashed solid double groove ridge inset or outset.
- Short hand properties
Some properties are so-called shorthands, i.e. you may specify several properties with a single one. These properties are separated by spaces. There are two kinds: some shorthands allow you to specify properties of the same kind, others to specify properties of different kinds.
For example the "same kind" margin property allows to set all four sides of a box (vs. using margin-top, margin-right etc.)
margin:0.5cm 1cm, 0.5cm 1cm
CSS shortcut multi-typed properties include: border, border-top, border-right, border-bottom, border-left, outline, background, font, and list-style. An example of these "several kinds of value" properties would be the border property. It's syntax is:
border: { [ border-width ] [ border-style ] [ border-color ] | inherit } ;
Here is an example:
#h1 { border: 2px dotted black; }
- Summary
The exist many kinds of values and there is an underlying logic to the scheme which allows you to guess what kind of values you should use for simple properties. However, people who rarely code CSS have to consult the documentation. Fortunately several web sites (e.g. the ones we list in the Resources on the web section do that very well...
In addition, read both the CSS text styling tutorial and the CSS color and background tutorial
7.3 The display and visibility attributes
Let's recall the most important typographic element types:
(1) Blocks, i.e. elements that should start a new paragraph
HTML examples: <p>, <h2>, <div>
(2) Lists and list elements
HTML example: <ul>, <ol>, <li>
(3) Inline elements
HTML examples: <b>, <strong>, <span>
(4) Tables
HTML examples: <table>, <tr>, <td>
By default, HTML will display each element as either a kind of block, list element, inline or table element. Each of these use the so-called boxing model we shall introduce below. Yut you are free to change the way these boxes behave. "Raw" XML on the other hand doesn't include any styling information. Therefore, the first operation when dealing with your own XML is to define the display property for each element. Otherwise, in HTML web design, you'd mostly use the display attribute to deal with all sorts of list items, e.g. menus.
In CSS 2, there about 15-20 different display types, some of which don't work yet in some browsers. Examples that should work with all browsers:
display: block; display: inline; display: list-item; display: none;
As we said, it is perfectly feasible to change the way HTML renders an element, e.g. you could display <li> elements of a list in a row, separated by dashes (CSS 2.1 needed for the dashes).
The display feature, can be used to censor the rendering of en element.
@media print { #menu { display: none; } }
An other useful property is visibility. E.g. to hide a menu in an alternate simple style you could say:
#menu { visibility: hidden; }
The visibility property can be either: visible, hidden, collapse. It may be used to build scroll down menus and other interactive user widgets.
7.4 Typographical properties
We only shall shortly introduce these properties, since detailed explanations can be found on numerous web sites.
Overview of font properties
Text alignment properties
7.5 Fonts
Using fonts is both fairly simple and tricky. Simple, because the font-family property is easy to use. Tricky, because most fonts are not available on all machines and because you could fine-tune display with kerning and other font adjustment techniques.
CSS defines five generic font families that each browser must implement. However, letter dimensions do not need to be the same and this means trouble for designers who aim at pixel precise complex layouts. The five generic families are:
- serif
- sans-serif
- monospace
- cursive
- fantasy
Typically, in order to ensure that fonts can be displayed you always should include a generic fall-back font by using a so-called "font stacks" like this:
* { font-family: Cambria, Georgia, serif; }
This property specification means that by default the browser should use Cambria. This font doesn't exist on some machines (e.g. Ubuntu) so they could then use Georgia or eventually the serif system font if Georgia is missing too.
Below we list a few popular stacks
font-family: Cambria, Georgia, serif; font-family: "Times New Roman", Times, serif; font-family: Calibri, Verdana, sans-serif; font-family: Arial, Helvetica, sans-serif; font-family: "Courier New", Courier, monospace; font-family: "Comic Sans", fantasy; font-family: "Comic Sans MS", cursive;
Let's just look at the third stack. Calibri is a modern Microsoft font that is good for both screen and print and not available on many system. Verdana is a fairly modern irregular font for screens. Arial is fairly ugly but ok and widely available. Sans-serif would be the default sans serif font of your web browser
Selecting a font that both looks good and is readable is not an easy matter.You may have a look at the font readability article.
If you really must make sure that all users are experiencing the same font, there is a technical solution, i.e. you can embed font files like this.
@font-face { font-family: "Cambria"; font-style: normal; font-weight: normal; src: url("fonts/Cambria.otf") format("opentype"); }
However, this is not a foolproof solution either, since many older browser don't support this, since you may have to buy a license and finally since several font file formats exist and not all browsers support these.
Safari, Firefox and Opera support .ttf, .otf and IE supports .eot. That can be solved by providing several URLs for loading a font file, e.g.:
@font-face { font-family: "Cambria"; font-style: normal; font-weight: normal; src: url("fonts/Cambria.otf") format("opentype"), url("fonts/Cambria.eot") format("embedded-opentype"); }
7.6 CSS Box structure
Each HTML element is a box, defined by CSS, with a margin (outside), a border, a padding between the border and content. Each of these "components" are defined by some properties you can set for each side.
In addition, there are shortcuts to set all four sides. Shortcuts that allow to specify all four sides do it clockwise, starting from the top: top, right, bottom, left (The mnemonic to remember this is "TRouBLe").
Borders, margins and colors properties (there are many more!)
Simple example
<p style="margin:0.5cm; padding:0.5cm; border:2pt; border-style:groove"> <strong style="border-style:dotted;">HELLO</strong> YOU. </p>
Will show like this:
HELLO YOU.
Read the CSS box model tutorial for more information about the boxing model.
As we said before, please do adopt a good a online reference manual such as the SitePoint CSS Reference or HTMLPedia in order to find all properties of a given kind and to learn what values you may use.
7.7 Floats, positioning and layout
The float property allows to position elements, e.g. a picture so that text can float around it. In addition floats are used to create so-called fluid layouts that adapt very well to both large and small screens.
CSS 2 then defines four positioning properties: left, right, top and bottom. These allow to position an element with respect to its "normal" position, or with respect to the viewport (what the user sees on the screen) and with respect to a parent element. To define one of these modes, use the position property.
Learn use of floats in the CSS float tutorial and more about positioning in the CSS positioning tutorial
8 Printing with style
CSS 2 is not really made for printing. However in modern CSS 2.1 browsers, there are some features that you should use. All modern browsers do support CSS 2.1.
Firstly, as we already explained you may use alternative stylesheets or the @media at-rule to define specific styles for printing. In particular, you may get rid of all menus and other stuff that you don't need on paper. In addition, the @page at-rule allows to specify margin values for the "page" box.
Simple example:
@page {margin: 2.5cm}
Example that sets margins for various page types:
/* The default rule set a 2.5cm margin on top,bottom,left,right */ @page { margin: 2.5cm; } @page :left { margin-left: 3cm; } /* left pages */ @page :right { margin-right: 3cm; } /* right pages */ @page :first { margin-top: 5cm; } /* first page has an big top margin */
The CSS3 specification includes additional facilities for styling print. Check browser support before you use these features, e.g. following the links in the CSS compatibility article.
Read more about CSS for print in the CSS for print tutorial.
9 If your stylesheet doesn’t display as it should
Firstly, please validate your CSS (e.g. upload the CSS file):
Typical syntax mistakes (easy to detect)
- Missing punctuations in property declaration (":" or ";" or ",")
- misspelled property names
- missing brace { ....
Syntax mistakes that are hard to find:
- Check spelling of HTML element names, the on-line CSS validator will not detect this ! Therefore, start by validating your HTML code first, e.g. use the excellent W3C Markup Validation Service !
Compatibility issues:
- Check compatibility of your browser or at least check with Firefox or IE8. A very good web site is Quirksmode.
- If you still must plan for older browsers like IE8, you might avoid CSS 2.1 and stick to CSS 2.0. E.g. IE8 has some problems with a few 2.1 selectors and properties. In particular (I don't know why) CSS 2.1 selectors won't work with CSS for XML.
Logical issues:
- Remember that most properties are inherited from parent elements and that the last (same kind of) rule defined wins. I.e. the rule that defines what you get may not be the one that you are looking at ...
- If you use several stylesheet files, make sure to load these in the right order. Selectively load CSS files to see the effect of each.
- You may use the Firefox Web developper extension to analyse the CSS on a page. This extension is fairly complex and there exist simpler tools that do less, but enough for you probably.
10 Tools for CSS editing
See also Web authoring system. We recommend using a CSS-aware text editor like Brackets or Bluefish.
There exist browser-based tools, for example:
- Each navigator includes developments tools that allow to inspect CSS and to make changes. On y Windows systems, try hitting F12 and search for "inspector", "style editor", etc.
- There exist various browser addons.
As of 2014, we recommend exploring various online tools that allow to exploring and generating CSS3 code. For example
- CSS3 animations
- Animation tools
- Css Sandbox
- Code modifiers (to generate all these proprietary properties)
- Validation (as alternative to the official w3c validator who tends to produce too many CSS3 "not yet implemented" warnings)
11 Resources on the web
See CSS links for tutorials and other interesting links. Here we just include a short selection
- FireFox extensions that are useful
- Web developper allows to examine each CSS box on a page and display the CSS code that affects this box. (menu: Tools->Web developer->CSS->View Style Information, then click on box in the page and watch the side pane)
- Codeburner for Firefox provides searchable reference information and code examples for HTML and CSS.
- Online Manuals
- CSS Reference at SitePoint
- List of CSS Properties at HTMLPedia
- CSS Reference at w3Schools.com
- List of properties (W3C recommendation, Appendix F)
- Standards
- (CSS page of the W3C)
- (CSS 2 specification)
- CSS3 refers to series of specifications: See for current status
- (CSS selectors in JavaScript to access the DOM)
- Compatibility tables
- (consult this for IE 6/7! in particular)
- CSS Validator (use it please !)
-
- In EduTechWiki
- CSS category | https://edutechwiki.unige.ch/en/CSS_tutorial | CC-MAIN-2017-51 | refinedweb | 9,292 | 55.24 |
A guide to caching in ASP.NET Core
This post looks at the various techniques available in ASP.NET Core for caching. We'll look at caching of data, partial pages and full pages at the server and client level and explain when to use each.
Why cache?
Caching adds some complexity to an application and as developers we must always be cautious when making our applications more complex so why bother with caching at all? A few reasons spring to mind:
- It saves you money (bandwidth costs, fewer servers required)
- It provides a better experience for your customers
- Faster sites make more money and rank better in Google
Just to emphasise how much of a speed benefit you can achieve through caching, if your page requires database calls to render, then caching the page can sometimes be an order of magnitude faster. Even completely static MVC views, without any external calls are faster when cached.
Given all these benefits and the fact that it can be very easy to add caching to your sites, it makes it a very attractive proposition. You do have to be careful though and later in the article, we will discuss some of the problems that caching can introduce.
What to cache?
Choosing what to cache is highly dependent on application. Generally speaking, to maximize performance, we want to cache at the highest level we can get away with.
For assets such as CSS, JS and images, we should be aggressively caching at the browser level and a cache duration of a year or more is fairly standard.
For relatively static, non-personalised pages, we can cache the entire page at both client and server level.
If this is not possible, caching parts of a page can avoid unnecessary calls and help decrease response times.
At an even lower level, caching data to reduce calls to databases can be useful - particularly if the cached data is the result of multiple queries.
Generally speaking, many applications will use a combinations of the above techniques for different areas.
Where to cache?
It makes sense to instruct the web browser to cache pages that rarely change but it is important to be aware of the limitations of caching at the client.
Unlike server side caching, it is not possible to instruct the browser to invalidate cache entries. This means that we need to be very careful with cache durations. The current best practice advise is to use very high cache durations for static assets and simply change the filename if an update is necessary. Obviously this is not an option for web pages. We can hardly change the URL of published pages every time an update is required. Instead, for web pages, we need to set a much lower cache duration at the client and rely on the server to efficiently handle requests.
Using a CDN is beyond the scope of this article, but is always worth considering, especially given how easy it is to set up today.
We also need to think about how server-side caching works once we move beyond a single server instance. When you have a single server, in-memory caching is easy to set up and generally works perfectly well. Most commericial sites however run on multiple load-balanced servers and dealing with caching becomes significantly more complex.
You have two high-level choices to consider. Do you:
- Maintain a discrete cache on every server
- Use a centralised cache that each server accesses
The first option, although slightly faster, has too many negatives to be recommended as a general solution:
- Discrepancies between caches can cause major headaches
- It is difficult to invalidate cache entries
- Wasted RAM filled with duplicated data
Using sticky sessions (server affinity) can help avoid some issues but if you have multiple web servers, I strongly recommend you use a distributed cache solution, for all but the simplest of cases (i.e. caching static lookup data).
Caching data with IMemoryCache and IDistributedCache
The lowest level of caching in ASP.NET Core that we are going to discuss is the caching of data using IMemoryCache and IDistributedCache. These interfaces are the standard, in-built mechanisms for caching data in .NET Core. All other techniques that we discuss later in the article rely on IMemoryCache or IDistributedCache internally.
IMemoryCache
IMemoryCache is very similar to the System.Runtime.Caching.MemoryCache cache from .NET 4.
The interface itself is rather minimal:
public interface IMemoryCache : IDisposable { bool TryGetValue(object key, out object value); ICacheEntry CreateEntry(object key); void Remove(object key); }
This only tells half the story though because there are multiple extension methods available which make the API much richer and easier to use:
public static class CacheExtensions { public static TItem Get<TItem>(this IMemoryCache cache, object key); public static TItem Set<TItem>(this IMemoryCache cache, object key, TItem value, MemoryCacheEntryOptions options); public static bool TryGetValue<TItem>(this IMemoryCache cache, object key, out TItem value); ... }
You can register IMemoryCache in ConfigureServices using:
services.AddMemoryCache();
If you are using MVC though then it will be automatically registered.
In either case, if you specify IMemoryCache in a component's constructor then it will get resolved along with the rest of the dependency graph.
The following code shows a naive example of using IMemoryCache to avoid hitting the database. The example returns a cached version of the data if available, else it queries the database, caches the data and returns the result:
public class BlahService { private const string BlahCacheKey = "blah-cache-key"; private readonly IMemoryCache _cache; private readonly IDatabase _db; public BlahService(IMemoryCache cache, IDatabase db) { _cache = cache; _db = db; } public async Task<IEnumerable<Blah>> GetBlahs() { if (_cache.TryGet(BlahCacheKey, out IEnumerable<Blah> blahs)) { return blahs; } blahs = await _db.getAll<Blah>(...); _cache.Set(BlahCacheKey, blahs, ...); return blahs; } }
When saving to IMemoryCache, MemoryCacheEntryOptions provides you with many ways to expire cache content. Options include absolute expiry (a fixed time), sliding expiry (time since last accessed) and expiry based on a token which is a powerful technique for creating dependencies between cache items. There are also overloads of Set which allow you to choose an expiration time directly. Here are a few examples:
//absolute expiration using TimeSpan _cache.Set("key", item, TimeSpan.FromDays(1)); //absolute expiration using DateTime _cache.Set("key", item, new DateTime(2020, 1, 1)); //sliding expiration (evict if not accessed for 7 days) _cache.Set("key", item, new MemoryCacheEntryOptions { SlidingExpiration = TimeSpan.FromDays(7) }); //use both absolute and sliding expiration _cache.Set("key", item, new MemoryCacheEntryOptions { AbsoluteExpirationRelativeToNow = TimeSpan.FromDays(30), SlidingExpiration = TimeSpan.FromDays(7) }); // use a cancellation token var tokenSource = new CancellationTokenSource(); var token = new CancellationChangeToken(tokenSource.Token); _cache.Set("key", item, new MemoryCacheEntryOptions().AddExpirationToken(token));
When using cancellation tokens, you can store the CancellationTokenSource itself in the cache and access it when you need to. To evict all cache entries using tokens from a particular CancellationTokenSource, you can just call the Cancel method:
tokenSource.Cancel();
The documentation provides full details for all the options you can use with IMemoryCache.
IDistributedCache
For web farm scenarios, you will want to make use of IDistributedCache instead of IMemoryCache:
public interface IDistributedCache { byte[] Get(string key); Task<byte[]> GetAsync(string key); void Set(string key, byte[] value, DistributedCacheEntryOptions options); Task SetAsync(string key, byte[] value, DistributedCacheEntryOptions options); void Refresh(string key); Task RefreshAsync(string key); void Remove(string key); Task RemoveAsync(string key); }
The interface provides similar functionality to IMemoryCache but there are some notable differences:
- Additional async methods
- Refresh methods (which just reset sliding expirations without retrieving data as far as I can tell)
- Byte based rather than object based (though extension methods add the ability to use string values)
This last change means that you will need to serialize any objects being stored yourself. The example below uses Json.NET for this:
public async Task SaveToCache<T>(string key, T item, int expirationInHours) { var json = JsonConvert.SerializeObject(item); await _cache.SetStringAsync(key, json, new DistributedCacheEntryOptions { AbsoluteExpirationRelativeToNow = TimeSpan.FromHours(expirationInHours) }); } public async Task<T> RetrieveFromCache<T>(string key) { var json = await _cache.GetStringAsync(key); return JsonConvert.DeserializeObject<T>(json); }
DistributedCacheEntryOptions offers absolute and sliding expiration much like MemoryCacheEntryOptions but token based expiration is absent. This makes adding cache dependencies much more of a challenge and you will need to roll your own implementation if you need this functionality.
There are three Microsoft implementations of the IDistributedCache interface currently available. These include a local, in-memory version ideal for development, plus Redis and SQL Server versions. Given that SQL Server is disk based rather than in-memory, I can't imagine many people opting for this version.
The local in-memory version of IDistributedCache is part of Microsoft.Extensions.Caching.Memory so is already brought in by the MVC package. If you should need to manually add it, you can use:
services.AddDistributedMemoryCache();
The Redis implementation is available in the Microsoft.Extensions.Caching.Redis.Core NuGet package. After referencing the NuGet, simply add the following to ConfigureServices:
services.AddDistributedRedisCache (option => { option.Configuration = "your connection string"; option.InstanceName = "your instance name"; });
Caching partial pages with Tag Helpers
There is no doubt that caching of data can significantly speed up server responses but we can often go one step further and cache rendered page output rather than (or in addition to) raw data. Partial page caching is available using the built-in Caching Tag Helpers.
The cache tag helper
At it's simplest, you can wrap part of a view in cache tags to enable caching:
<cache>...</cache>
This results in that part of the page being cached for a default duration of 20 minutes.
Obviously caching an arbitrary part of the page is next to useless unless that part of the page is expensive to render. One obvious candidate for caching is a view component call. If you are not familiar with view components then you can think of them as more capable successors to child actions. They are very useful for secondary parts of the page such as sidebars. If your sidebar is dynamically generated from a database then caching the result can be extremely beneficial.
<cache expires- @await Component.InvokeAsync("BlogPosts", new { tag = "popular" }) </cache>
The above example caches the blog posts view component for 10 minutes.
The cache tag helper allows you to vary the cache (i.e. create multiple separate copies) by many different criteria including headers, queries, routes, cookies and even users.
<cache expires- ...user specific content... </cache>
I am not sure how well some of these options will scale on busy sites, but the cache tag helper is certainly very feature rich. See the docs for full details.
The distributed-cache tag helper
As with IMemoryCache, the Cache tag helper has a sibling for use in web farm situations where a distributed solution is required.
<distributed-cache @await Component.InvokeAsync("BlogPosts", new { tag = "popular" }) </Cache>
In use, the distributed cache tag helper is very similar to the in memory version. Other than the tag name change from cache to distributed-cache, the only notable difference is the requirement of a name attribute for the distributed version. This value is used to generate a key for the cache entry.
Internally, the tag helper uses the IDistributedCache outlined in the previous section. If you do not configure an IDistributedCache implementation in ConfigureServices then the in-memory version is used without any configuration necessary.
Caching full pages with response caching
The highest level of caching that we can make use of is caching of the entire page. Caching full pages in the browser results in the very minimum of server load and caching fully rendered pages on the server can also hugely reduce load and response times.
In .NET core, these two techniques are closely related. We have a ResponseCache attribute which is used to set cache headers and we have a ResponseCaching piece of middleware which can optionally be used to enable server side caching.
Caching in the browser
You can set cache headers manually using Response.Headers but the preferred approach for caching actions is to make use of the ResponseCache attribute which can be applied to both actions and controllers.
[ResponseCache(Duration = 3600)]
Duration is measures in seconds so the above attribute would cache the page in the browser for 3600 seconds or one hour.
Instead of specifying values for each instance of the attribute, we can also configure one or more cache profiles. Cache profiles are configured in ConfiguresServices when you add the MVC middleware:
services.AddMvc(options => { options.CacheProfiles.Add("Hourly", new CacheProfile() { Duration = 60 * 60 // 1 hour }); options.CacheProfiles.Add("Weekly", new CacheProfile() { Duration = 60 * 60 * 24 * 7 // 7 days }); });
You can then reference the cache profile names in the ResponseCache attributes
[ResponseCache(CacheProfileName = "Weekly")]
You can also explicitly disable any caching with the following:
[ResponseCache(Location = ResponseCacheLocation.None, NoStore = true)]
Note that both Location and NoStore are required. NoStore returns the standard "cache-control: no-store" header but some older proxies do not understand this so Location = ResponseCacheLocation.None adds "no-cache" values to cache-control and pragma headers.
Caching at the server
As mentioned above, caching at the server uses a piece of middleware which reads the values set by the ResponseCache attribute and caches the page appropriately.
The response caching middleware is in a separate NuGet package so you will need to add a package reference to Microsoft.AspNetCore.ResponseCaching in order to use it. Once installed, it can be added to the pipeline by adding the following to ConfigureServices:
services.AddResponseCaching();
The middleware takes the cache duration from the cache-control header set by the Response Cache attribute. It also respects the VaryByHeader option allowing you to cache multiple versions of the page. One common use for this would be to vary by Accept-encoding header so you can cache both gzipped and non-gzipped responses, plus any other compression algorithms you are using. This of course assumes that you are compressing within your application rather than at the reverse proxy level.
As well as the standard VaryByHeader option, you can use the ResponseCache attribute to specify a VaryByQuery value which is used exclusively by the server side response caching middleware. As you would expect, this causes the middleware to store additional response copies based on the query string values specified.
Limitations
Server side response caching can provide astonishing gains in speed but it is important to be aware of the limitations of such an approach.
If you are caching fairly static content for anonymous users and the pages have no personalisation or forms then full-page caching is ideal. Unfortunately, this is rarely true and you will run into issues if you try to cache pages in these other situations.
In fact the built-in response caching middleware will not cache the page if any of the following are true:
- The response code is not 200
- The request method is not GET or HEAD
- An Authorization header is present
- A Set-Cookie header is present
In addition, using the Anti-CSRF features of MVC will override any explicit cache-control header you have set and replace it with "no-cache, no-store" resulting in your page not being cached. This is essential because this feature works by setting a cookie and embedding a form value so you do not want to cache these values.
Cache invalidation
One common approach to full page caching is to cache on the client for a short period of time and on the server for a much longer period. This technique relies on the fact that we can typically remove cache entries early on the server if necessary. This way we can effectively cache frequently accessed pages indefinitely and only invalidate the cache and store a new version if the page changes.
Unfortunately, the built-in response caching middleware makes this very difficult. Firstly, the same cache duration is used for both client and server caches. Secondly, currently there is no easy way to invalidate cache entries. This is a real shame and I hope it is something that will change. For now I ended up writing my own basic implementation which we will look at next time.
Caching JS, CSS, Images etc.
Images and other static files are served by adding the static files middleware. A typical registration in the Configure method of startup.cs looks like this:
app.UseStaticFiles();
This code will enable the serving of static files but not in the most efficient way. By default, no cache headers are used so the browser will request these files again and again, slowing your sites and putting more load on your server.
The good news is that it is very easy to change the static files registration code to enable browser caching. Here we set caching to a year:
app.UseStaticFiles(new StaticFileOptions { OnPrepareResponse = (context) => { var headers = context.Context.Response.GetTypedHeaders(); headers.CacheControl = new CacheControlHeaderValue { Public = true, MaxAge = TimeSpan.FromDays(365) }; } });
Summary
Caching can drastically reduce your costs and also provide a more responsive site for your customers. We looked at a number of different techniques from low level caching of data through to entire page caching at both the client and server. We discussed some gotchas to be aware of when adding caching to your applications and also explained about a few limitations when using the built-in response caching.
Next time, we'll take a look at writing our own response caching solution.
Useful or Interesting?
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Thank you very much! This is great post! | https://www.devtrends.co.uk/blog/a-guide-to-caching-in-asp.net-core | CC-MAIN-2017-34 | refinedweb | 2,930 | 53.81 |
English Phrasal verbs.txt
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ask someone out
invite on a date (i.e.:Brian asked Judy out to dinner and a movie.)
ask around
ask many people the same question (i.e.:I asked around but nobody has seen my wallet.)
add up to something
equal (i.e.:Your purchases add up to $205.32.)
back something up
reverse (i.e.:You'll have to back up your car so that I can get out.)
back someone up
support (i.e.:My wife backed me up over my decision to quit my job.)
blow up
explode (i.e.:The racing car blew up after it crashed into the fence.)
blow something up
add air (i.e.:We have to blow 50 balloons up for the party.)
break down
stop functioning (vehicle
break down
get upset (i.e.:The woman broke down when the police told her that her son had died.)
break something down
divide into smaller parts (i.e.:Our teacher broke the final project down into three separate parts.)
break in
force entry to a building (i.e.:Somebody broke in last night and stole our stereo.)
break into something
enter forcibly (i.e.:The firemen had to break into the room to rescue the children.)
break something in
wear something a few times so that it doesn't look/feel new (i.e.:I need to break these shoes in before we run next week.)
break in
interrupt (i.e.:The TV station broke in to report the news of the president's death.)
break up
end a relationship (i.e.:My boyfriend and I broke up before I moved to America.)
break up
start laughing (informal) (i.e.:The kids just broke up as soon as the clown started talking.)
break out
escape (i.e.:The prisoners broke out of jail when the guards weren't looking.)
break out in something
develop a skin condition (i.e.:I broke out in a rash after our camping trip.)
bring someone down
make unhappy (i.e.:This sad music is bringing me down.)
bring someone up
raise a child (i.e.:My grandparents brought me up after my parents died.)
bring something up
start talking about a subject (i.e.:My mother walks out of the room when my father brings up sports.)
bring something up
vomit (i.e.:He drank so much that he brought his dinner up in the toilet.)
call around
phone many different places/people (i.e.:We called around but we weren't able to find the car part we needed.)
call someone back
return a phone call (i.e.:I called the company back but the offices were closed for the weekend.)
call something off
cancel (i.e.:Jason called the wedding off because he wasn't in love with his fianc.)
call on someone
ask for an answer or opinion (i.e.:The professor called on me for question 1.)
call on someone
visit someone (i.e.:We called on you last night but you weren't home.)
call someone up
phone (i.e.:Give me your phone number and I will call you up when we are in town.)
calm down
relax after being angry (i.e.:You are still mad. You need to calm down before you drive the car.)
not care for someone/something
not like (formal) (i.e.:I don't care for his behaviour.)
catch up
get to the same point as someone else (i.e.:You'll have to run faster than that if you want to catch up with Marty.)
check in
arrive and register at a hotel or airport (i.e.:We will get the hotel keys when we check in.)
leave a hotel (i.e.:You have to check out of the hotel before 11:00 AM.)
check someone/something out
look at carefully
look at (informal) (i.e.:Check out the crazy hair on that guy!)
cheer up
become happier (i.e.:She cheered up when she heard the good news.)
cheer someone up
make happier (i.e.:I brought you some flowers to cheer you up.)
chip in
help (i.e.:If everyone chips in we can get the kitchen painted by noon.)
clean something up
tidy
come across something
find unexpectedly (i.e.:I came across these old photos when I was tidying the closet.)
come apart
separate (i.e.:The top and bottom come apart if you pull hard enough.)
come down with something
become sick (i.e.:My nephew came down with chicken pox this weekend.)
come forward
volunteer for a task or to give evidence (i.e.:The woman came forward with her husband's finger prints.)
come from somewhere
originate in (i.e.:The art of origami comes from Asia.)
count on someone/something
rely on (i.e.:I am counting on you to make dinner while I am out.)
cross something out
draw a line through (i.e.:Please cross out your old address and write your new one.)
cut back on something
consume less (i.e.:My doctor wants me to cut back on sweets and fatty foods.)
cut something down
make something fall to the ground (i.e.:We had to cut the old tree in our yard down after the storm.)
cut in
interrupt (i.e.:Your father cut in while I was dancing with your uncle.)
cut in
pull in too closely in front of another vehicle (i.e.:The bus driver got angry when that car cut in.)
cut in
start operating (of an engine or electrical device) (i.e.:The air conditioner cuts in when the temperature gets to 22C.)
cut something off
remove with something sharp (i.e.:The doctors cut off his leg because it was severely injured.)
cut something off
stop providing (i.e.:The phone company cut off our phone because we didn't pay the bill.)
cut someone off
take out of a will (i.e.:My grandparents cut my father off when he remarried.)
cut something out
remove part of something (usually with scissors and paper) (i.e.:I cut this ad out of the newspaper.)
do someone/something over
beat up
do something over
do again (N.Amer.) (i.e.:My teacher wants me to do my essay over because she doesn't like my topic.)
do away with something
discard (i.e.:It's time to do away with all of these old tax records.)
do something up
fasten
dress up
wear nice clothing (i.e.:It's a fancy restaurant so we have to dress up.)
drop back
move back in a position/group (i.e.:Andrea dropped back to third place when she fell off her bike.)
drop in/by/over
come without an appointment (i.e.:I might drop in/by/over for tea sometime this week.)
drop someone/something off
take someone/something somewhere and leave them/it there (i.e.:I have to drop my sister off at work before I come over.)
drop out
quit a class
eat out
eat at a restaurant (i.e.:I don't feel like cooking tonight. Let's eat out.)
end up
eventually reach/do/decide (i.e.:We ended up renting a movie instead of going to the theatre.)
fall apart
break into pieces (i.e.:My new dress fell apart in the washing machine.)
fall down
fall to the ground (i.e.:The picture that you hung up last night fell down this morning.)
fall out
separate from an interior (i.e.:The money must have fallen out of my pocket.)
fall out
(of hair
figure something out
understand
fill something in
to write information in blanks (Br.E.) (i.e.:Please fill in the form with your name
fill something out
to write information in blanks (N.Amer.) (i.e.:The form must be filled out in capital letters.)
fill something up
fill to the top (i.e.:I always fill the water jug up when it is empty.)
find out
discover (i.e.:We don't know where he lives. How can we find out?)
find something out
discover (i.e.:We tried to keep the time of the party a secret
get something across/over
communicate
get along/on
like each other (i.e.:I was surprised how well my new girlfriend and my sister got along/on.)
get around
have mobility (i.e.:My grandfather can get around fine in his new wheelchair.)
get away
go on a vacation (i.e.:We worked so hard this year that we had to get away for a week.)
get away with something
do without being noticed or punished (i.e.:Jason always gets away with cheating in his maths tests.)
get back
return (i.e.:We got back from our vacation last week.)
get something back
receive something you had before (i.e.:Liz finally got her Science notes back from my room-mate.)
get back at someone
retaliate
get back into something
become interested in something again (i.e.:I finally got back into my novel and finished it.)
get on something
step onto a vehicle (i.e.:We're going to freeze out here if you don't let us get on the bus.)
get over something
recover from an illness
get over something
overcome a problem (i.e.:The company will have to close if it can't get over the new regulations.)
get round to something
finally find time to do (N.Amer.: get around to something) (i.e.:I don't know when I am going to get round to writing the thank you cards.)
get together
meet (usually for social reasons) (i.e.:Let's get together for a BBQ this weekend.)
get up
get out of bed (i.e.:I got up early today to study for my exam.)
get up
stand (i.e.:You should get up and give the elderly man your seat.)
give someone away
reveal hidden information about someone (i.e.:His wife gave him away to the police.)
give someone away
take the bride to the altar (i.e.:My father gave me away at my wedding.)
give something away
ruin a secret (i.e.:My little sister gave the surprise party away by accident.)
give something away
give something to someone for free (i.e.:The library was giving away old books on Friday.)
give something back
return a borrowed item (i.e.:I have to give these skates back to Franz before his hockey game.)
give in
reluctantly stop fighting or arguing (i.e.:My boyfriend didn't want to go to the ballet
give something out
give to many people (usually at no cost) (i.e.:They were giving out free perfume samples at the department store.)
give something up
quit a habit (i.e.:I am giving up smoking as of January 1st.)
give up
stop trying (i.e.:My maths homework was too difficult so I gave up.)
go after someone
follow someone (i.e.:My brother tried to go after the thief in his car.)
go after something
try to achieve something (i.e.:I went after my dream and now I am a published writer.)
go against someone
compete
go ahead
start
go back
return to a place (i.e.:I have to go back home and get my lunch.)
go out
leave home to go on a social event (i.e.:We're going out for dinner tonight.)
go out with someone
date (i.e.:Jesse has been going out with Luke since they met last winter.)
go over something
review (i.e.:Please go over your answers before you submit your test.)
go over
visit someone nearby (i.e.:I haven't seen Tina for a long time. I think I'll go over for an hour or two.)
go without something
suffer lack or deprivation (i.e.:When I was young
grow apart
stop being friends over time (i.e.:My best friend and I grew apart after she changed schools.)
grow back
regrow (i.e.:My roses grew back this summer.)
grow up
become an adult (i.e.:When Jack grows up he wants to be a fireman.)
grow out of something
get too big for (i.e.:Elizabeth needs a new pair of shoes because she has grown out of her old ones.)
grow into something
grow big enough to fit (i.e.:This bike is too big for him now
hand something down
give something used to someone else (i.e.:I handed my old comic books down to my little cousin.)
hand something in
submit (i.e.:I have to hand in my essay by Friday.)
hand something out
to distribute to a group of people (i.e.:We will hand out the invitations at the door.)
hand something over
give (usually unwillingly) (i.e.:The police asked the man to hand over his wallet and his weapons.)
hang in
stay positive (N.Amer.
hang on
wait a short time (informal) (i.e.:Hang on while I grab my coat and shoes!)
hang out
spend time relaxing (informal) (i.e.:Instead of going to the party we are just going to hang out at my place.)
hang up
end a phone call (i.e.:He didn't say goodbye before he hung up.)
hold someone/something back
prevent from doing/going (i.e.:I had to hold my dog back because there was a cat in the park.)
hold something back
hide an emotion (i.e.:Jamie held back his tears at his grandfather's funeral.)
hold on
wait a short time (i.e.:Please hold on while I transfer you to the Sales Department.)
hold onto someone/something
hold firmly using your hands or arms (i.e.:Hold onto your hat because it's very windy outside.)
hold someone/somethingup
rob (i.e.:A man in a black mask held the bank up this morning.)
keep on doing something
continue doing (i.e.:Keep on stirring until the liquid comes to a boil.)
keep something from someone
not tell (i.e.:We kept our relationship from our parents for two years.)
keep someone/something out
stop from entering (i.e.:Try to keep the wet dog out of the living room.)
keep something up
continue at the same rate (i.e.:If you keep those results up you will get into a great college.)
let someone down
fail to support or help
let someone in
allow to enter (i.e.:Can you let the cat in before you go to school?)
look after someone/something
take care of (i.e.:I have to look after my sick grandmother.)
look down on someone
think less of
look for someone/something
try to find (i.e.:I'm looking for a red dress for the wedding.)
look forward to something
be excited about the future (i.e.:I'm looking forward to the Christmas break.)
look into something
investigate (i.e.:We are going to look into the price of snowboards today.)
look out
be careful
look out for someone/something
be especially vigilant for (i.e.:Don't forget to look out for snakes on the hiking trail.)
look something over
check
look something up
search and find information in a reference book or database (i.e.:We can look her phone number up on the Internet.)
look up to someone
have a lot of respect for (i.e.:My little sister has always looked up to me.)
make something up
invent
make up
forgive each other (i.e.:We were angry last night
make someone up
apply cosmetics to (i.e.:My sisters made me up for my graduation party.)
mix something up
confuse two or more things (i.e.:I mixed up the twins' names again!)
pass away
die (i.e.:His uncle passed away last night after a long illness.)
pass out
faint (i.e.:It was so hot in the church that an elderly lady passed out.)
pass something out
give the same thing to many people (i.e.:The professor passed the textbooks out before class.)
pass something up
decline (usually something good) (i.e.:I passed up the job because I am afraid of change.)
pay someone back
return owed money (i.e.:Thanks for buying my ticket. I'll pay you back on Friday.)
pay for something
be punished for doing something bad (i.e.:That bully will pay for being mean to my little brother.)
pick something out
choose (i.e.:I picked out three sweaters for you to try on.)
point someone/something out
indicate with your finger (i.e.:I'll point my boyfriend out when he runs by.)
put something down
put what you are holding on a surface or floor (i.e.:You can put the groceries down on the kitchen counter.)
put someone down
insult
put something off
postpone (i.e.:We are putting off our trip until January because of the hurricane.)
put something out
extinguish (i.e.:The neighbours put the fire out before the firemen arrived.)
put something together
assemble (i.e.:I have to put the crib together before the baby arrives.)
put up with someone/something
tolerate (i.e.:I don't think I can put up with three small children in the car.)
put something on
put clothing/accessories on your body (i.e.:Don't forget to put on your new earrings for the party.)
run into someone/something
meet unexpectedly (i.e.:I ran into an old school-friend at the mall.)
run over someone/something
drive a vehicle over a person or thing (i.e.:I accidentally ran over your bicycle in the driveway.)
run over/through something
rehearse
run away
leave unexpectedly
run out
have none left (i.e.:We ran out of shampoo so I had to wash my hair with soap.)
send something back
return (usually by mail) (i.e.:My letter got sent back to me because I used the wrong stamp.)
set something up
arrange
set someone up
trick
shop around
compare prices (i.e.:I want to shop around a little before I decide on these boots.)
show off
act extra special for people watching (usually boastfully) (i.e.:He always shows off on his skateboard)
sleep over
stay somewhere for the night (informal) (i.e.:You should sleep over tonight if the weather is too bad to drive home.)
sort something out
organize
stick to something
continue doing something
switch something off
stop the energy flow
switch something on
start the energy flow
take after someone
resemble a family member (i.e.:I take after my mother. We are both impatient.)
take something apart
purposely break into pieces (i.e.:He took the car brakes apart and found the problem.)
take something back
return an item (i.e.:I have to take our new TV back because it doesn't work.)
take off
start to fly (i.e.:My plane takes off in five minutes.)
take something off
remove something (usually clothing) (i.e.:Take off your socks and shoes and come in the lake!)
take something out
remove from a place or thing (i.e.:Can you take the garbage out to the street for me?)
take someone out
pay for someone to go somewhere with you (i.e.:My grandparents took us out for dinner and a movie.)
tear something up
rip into pieces (i.e.:I tore up my ex-boyfriend's letters and gave them back to him.)
think back
remember (often + to
think something over
consider (i.e.:I'll have to think this job offer over before I make my final decision.)
throw something away
dispose of (i.e.:We threw our old furniture away when we won the lottery.)
turn something down
decrease the volume or strength (heat
turn something down
refuse (i.e.:I turned the job down because I don't want to move.)
turn something off
stop the energy flow
turn something on
start the energy
turn something up
increase the volume or strength (heat
turn up
appear suddenly (i.e.:Our cat turned up after we put posters up all over the neighbourhood.)
try something on
sample clothing (i.e.:I'm going to try these jeans on
try something out
test (i.e.:I am going to try this new brand of detergent out.)
use something up
finish the supply (i.e.:The kids used all of the toothpaste up so we need to buy some more.)
wake up
stop sleeping (i.e.:We have to wake up early for work on Monday.)
warm someone/something up
increase the temperature (i.e.:You can warm your feet up in front of the fireplace.)
warm up
prepare body for exercise (i.e.:I always warm up by doing sit-ups before I go for a run.)
wear off
fade away (i.e.:Most of my make-up wore off before I got to the party.)
work out
exercise (i.e.:I work out at the gym three times a week.)
work out
be successful (i.e.:Our plan worked out fine.)
work something out
make a calculation (i.e.:We have to work out the total cost before we buy the house.)
Card Set Information
Author:
MendaLerenda
ID:
237270
Filename:
English Phrasal verbs.txt
Updated:
2013-09-26 22:30:35
English Phrasal verbs
Folders:
Description:
200 English Phrasal verbs with meaning and an example.
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Saving data in the database takes you a lot of time but, In this tutorial I will teach you how to save multiple data using C# and SQL server 2005. With the use of this method, it wil lessen your work when saving data in the database.This method has the ability to save multiple data in just a click.
Let’s begin:
Create a database and name it “employeedb”.
After creating the database, open Microsoft Visual Studio 2008 and create new Windows Form Application for C#. Then do the following design of a Form as shown below.
Go to the Solution Explorer, double click the “View Code” to display the code editor.
In the code editor, declare all the classes and variables that are needed.
Note: Put using System.Data.SqlClient; above the namespace to access sql server library.
//initialize all classes SqlConnection conn = new SqlConnection(); SqlCommand cmd = new SqlCommand(); SqlDataAdapter da = new SqlDataAdapter(); DataTable dt = new DataTable(); //declaring variables string query; int result;
After declaring the classes and variables, establish a connection betweenSQL server and C#.net in the first load of the Form.
private void Form1_Load(object sender, EventArgs e) { conn.ConnectionString = "Data Source=.\\SQLEXPRESS;database=employeedb;trusted_connection=true;"; }
After that, double click the “Save” button and do the following code in the method. This code is for saving multiple data in just a click.
private void button1_Click(object sender, EventArgs e) { try { //opening connection conn.Open(); int maxrow = dataGridView1.Rows.Count - 2; //create a loop for getting the total rows in the datagridview that have filled up. for (int i = 0; i <= maxrow ; i++) { //create an insert query; query = "INSERT INTO tblemployee (Name,Address,Contact,Emailadd) VALUES('" + dataGridView1.Rows[i].Cells[0].FormattedValue +"','" + dataGridView1.Rows[i].Cells[1].FormattedValue +"','" + dataGridView1.Rows[i].Cells[2].FormattedValue +"','" + dataGridView1.Rows[i].Cells[3].FormattedValue +"')"; //it holds the data to be executed. cmd.Connection = conn; cmd.CommandText = query; //execute the data. result = cmd.ExecuteNonQuery(); } //validate the result of the executed query. if (result > 0) { MessageBox.Show("Data has been saved in the SQL database"); } else { MessageBox.Show("SQL QUERY ERROR"); } //closing connection conn.Close(); } catch (Exception ex)//catch exeption { //displaying error message. MessageBox.Show(ex.Message); } } }
Output:
For all students who need programmer for your thesis system or anyone who needs a sourcecode in any programming languages. You can contact me @ :
Mobile No. – 09305235027 – tnt | http://itsourcecode.com/2016/06/multiple-save-using-c-sql-server/ | CC-MAIN-2017-34 | refinedweb | 395 | 51.34 |
10 July 2008 17:26 [Source: ICIS news]
(releads, adds buyer reaction and detail throughout)
By Edward Cox
LONDON (ICIS news)--Dow Europe’s intention to end plastic resins pricing based on a market index formula was not unexpected but could give the company greater control over its prices, buyers said on Thursday.
?xml:namespace>
“Producers want to control variables but they can’t control ICIS, so they don’t like to be linked to something they can’t control,” said one buyer.
ICIS pricing, the global chemical market intelligence service, offers independent price assessments for key commodity chemicals that are widely used as benchmarks or price references in chemical transactions.
Dow’s new pricing system will affect low density polyethylene (LDPE), linear low density PE (LLDPE), high density PE (HDPE), polypropylene (PP), polystyrene (PS), acrylonitrile butadiene styrene (ABS) and styrene acrylonitrile (SAN) from 1 January 2009.
The company said that discontinuing the market index formula in Europe, ?xml:namespace>
“Dow is taking this action as part of a series of measures to begin to partly restore eroding margins in the face of unprecedented and unforeseen increases in feedstock costs,” Isidro Quiroga, commercial vice-president of Dow Basic Plastics for Europe,
“Discontinuing market index formula pricing will give us more flexibility to combat the volatility of these costs, which are impossible for us to avoid because of the current volatile high feedstock environment,” he added.
Buyers said that Dow’s announcement had not been entirely unexpected.
“It’s no great surprise, all producers have been saying this over the past two years,” said one buyer.
“Regardless of what they say, though, we still have prices fixed at the end of the month, and the end of the year with rebates,” he added.
Market index formulas, such as those from ICIS pricing, should be a reference but not an index, a Dow company source said.
“It’s not our aim to discredit [ICIS pricing], we want to bring the industry back into negotiation,” he said.
“There will be resistance so we will look for individual solutions,” he added.
One consumer said that 10-15 years ago everything was based on discussions which took the whole month but that it now was simpler to have indexing.
“Dow’s argument is to leave this behind but if it is dealing with a big consumer it may have to think twice,” he added.
Another said: “I don’t have a specific price index link with Dow but I can imagine they want to have a free hand to decide pricing.
"For buyers [price indexing] is like a guarantee, [it is] an official voice or an insurance policy that shows what is happening in the market.”
For more on plastics and res | http://www.icis.com/Articles/2008/07/10/9139397/Dow-seeks-to-control-its-polymer-prices.html | CC-MAIN-2015-11 | refinedweb | 457 | 53.65 |
On Thu, 9 Jul 2009 10:10:09 +0200, yersinia wrote: > > > %if 0%{?fedora} > 9 > > > BuildArch: noarch > > > %endif > > > > > > > Excellent. That's what I was looking for. > > > > No, it is not right for me. The BuildArch issue depends on the RPM version > and not from from distro version. It is simply bad style, IMHO, defining > in the SPEC file something that depends from the "distribution" (in the > large sense not only fedora). I never see > this style in RHEL package (appart some little package for the rpm keys > ecc). Ok is SUSE yes but, again, i don't like define a dependency based on > a "distro" version, if possible anyway. First of all, the original question was about "non-Fedora and older distributions (pre F10)". Above conditional does its job and enables a noarch sub-pkg only for Fedora > 9. "0%{?rhel} > 5" may be more future-proof, okay, but isn't true yet for any existing build-target. Also, as far as I know, %rhel and %dist are specific to koji/Plague EPEL builds, as stock RHEL and CentOS don't ship those macros. One needs the buildsys-macros package. In case I'm mistaken, and I don't have the time to verify that, what package defines those macros for RHEL? Finally, I don't agree with parts of the complaints. Either rpmbuild predefines a variables one can evaluate to check for a certain feature, or it doesn't. If it doesn't, I don't consider it "bad style" to eval %fedora/%rhel and make explicit what a conditional is trying to achieve. Even for a feature like this, that's better than hiding the details in a macro. Btw, we're miles away from clean multi-dist spec files, not only due to different package names. My experience with multi-dist spec files is that very often the packager loses overview due to overuse of conditionals and the added difficult of keeping changes in all conditional spec sections in sync with eachother. | https://www.redhat.com/archives/fedora-devel-list/2009-July/msg00706.html | CC-MAIN-2017-43 | refinedweb | 335 | 72.66 |
Forrest is able to use html files as content, but till now it uses
seamingly wierd extensions like ihtml and ehtml, that have come out of
different views of how Forrest should deal with them.
Recent needs have brought this to my attention, and I'd like to try and
close the issue.
Currently:
- ihtml -> cleaned html -> xdoc -> output
- ehtml -> pass as-is -> output (IIRC)
Basically what happens is that ehtml keeps all html tags till the
output, while ihtml removes all content that is not convertible to xdoc.
The reason for ihtml is that with it users can also see the content in
PDF and all other output formats.
The reason for ehtml is that sometimes one needs to add form elements or
other features to the pages that xdocs do not support.
Now, what remains to be decided is what to do with the 'html' extension.
Some wanted it to function as ihtml, some as ehtml.
Why would we need to have that extension work at all?
Simple: so that it becomes a snap to convert legacy sites to Forrest.
And for example make it possible for Gump to publish a simple unskinned
html report in case Forrest does not complete the run, *without* keeping
two source formats.
My last proposal was to do the following:
1 - make .html extensions work as .ihtml
2 - make it possible to insert namespaced html tags in the xdocs and
make these tags percolate through in the html output; this can
and should be extended also to fo and the like. In this case
ehtml pages would not be needed anymore, as users would write
namespaced xdocs (with xdoc and html namespaces)
3 - deprecate .ihtml and .ehtml
WDYT?
--
Nicola Ken Barozzi nicolaken@apache.org
- verba volant, scripta manent -
(discussions get forgotten, just code remains)
--------------------------------------------------------------------- | http://mail-archives.apache.org/mod_mbox/forrest-dev/200404.mbox/%3Cc4rlih$fc2$1@sea.gmane.org%3E | CC-MAIN-2017-17 | refinedweb | 302 | 77.98 |
4 months, 1 week ago.
How to choose PWN output pins?
I need to output four PWM signals on four different pins. How does one choose the pins?
Running on the Nucleo F401RE
My software is running and I look using a logic analyzer and I see only three of the four output pins with signals on them.
I found Peripheral Pins.c and the data structure const PinMap PinMap_PWM[] I'm guessing it is bad to choose pins that use the same timer. So I selected these four. PA_7 PA_0 PA_6 PB_6 Three of these are OK. PA_7 just has some millivolts of noise on it.
Here is test code
test code
#include "mbed.h" PwmOut testPin1(PA_7); PwmOut testPin2(PA_0); PwmOut testPin3(PA_6); PwmOut testPin4(PB_6); int main() { testPin1.period( 1.0 / 1000.0); // 1KHz testPin2.period( 1.0 / 1000.0); // 1KHz testPin3.period( 1.0 / 1000.0); // 1KHz testPin4.period( 1.0 / 1000.0); // 1KHz testPin1 = 0.1; testPin2 = 0.2; testPin3 = 0.3; testPin4 = 0.4; }
2 Answers
4 months, 1 week ago.
Which pin did not produce the PWM output on the 401? There are times where it makes sense to separate the PWMs by timer and other times it does not. In your example above the timebase timer should be capable of running all 4 PWMs off the same internal clock. You should be able to move the outputs around and see that you still get the PWM out.
I'm now thinking this was an electrical problem, not software. Just recently I have a 5V power supply in the same breadboard as the F401RE. Could have had an accident. I move swap hardware and the problem goes away.
But STILL. I need to understand . So you are saying I can use ANY combination of pins from PinMap_PWM[] . Even all of them at once?
When should I separate them by timer?
What should I be reading? The API reference does not go into this level of detail.posted by 15 May 2017
I would start at the STM 401 datasheet level off of the ST website. There is a good block diagram of the timers in there. You'll notice that the part is split into two "Advanced Peripheral Busses" (APBs) which have different internal clocks. That may not matter for your application now but it might have importance later on. From there, go get the "Reference Guide" pdf off the ST website. That'll provide more insight into how the timers are programmed and what you can do with them. If you're doing simplistic timing then it really doesn't matter which timer you use. If you need to do *relational* timing (PWM phasing for example) then you need to worry about the timer - but the mbed API is not set up to do that type of timer programming. You'd have to import one of the many user libraries that do. If you're sticking to ST parts (for now) you can directly program the timers using ST's "HAL" interface which is a bit archaic but can set up any timer any way for your mbed code. There are a lot of good examples on here on how to use those calls in your mbed code. All that said, I would start by just assigning pins at a high level based on a pin map shown here () and not worry too much about the C code implementation at the lower level. Once you find you can't accomplish the timing characteristics then I would dig down a bit further. Also be sure to look at FastPWM as a better library for PWM if you're trying to do any dynamic PWM timing changes while running.posted by 17 May 2017
4 months ago.
Chris -
On your original question:
Your code may be executing properly but you may be incorrectly interpretting the signal outputs. The three outputs that appear to be operating correctly are all non-inverting outputs from their respective timers. The rising edges of the pulses from these three outputs should occur at essentially at the same time (there will be some small timing differences, since their timers are independent) with a common pulse period of 1 ms and pulse widths of 200, 300 and 400 us.
The output that does not appear to be operating correctly (PA_7) is an inverted output - the inverted output of Channel 1 of Timer1. Your code sets its duty cycle to 10%. What you should see at PA_7 is a logic level 0 for 900 us followed by a logic level 1 for 100 us, so this output should be at logic level 0 during the entire time that the other three pulses are at logic level 1. You could be missing this pulse if your logic analyzer is triggering off of one of the non-inverted outputs and you are not looking over multiple 1 ms periods.
Try using PA_8 instead of PA_7 for Channel 1 of Timer1. It is a non-inverted output and should act like the other three PWM signals.
On your follow-up questions:
1) You should be able to use any combination of pin names in the PWM list in Peripheral Pins.c without a hardware conflict - except the ones that are commented out. The PWM pin names that are commented out have conflicts with other mbed functions (e.g.. us_ticker and UART_2, the default uart) or conflicts with other timers.
2) Your Nucleo-F401RE board has four independent timers available for PWM output using the mbed API. These four timers include three different timer types, but the mbed API does not appear to take advantage of the features that differentiate them (aside from supporting the inverted Timer1 outputs). All four of these timers have four channels whose duty cycle can be independently programmed with a common period.
You definitely need to use different timers if you want to simultaneously generate different periods (eg. to vary the output frequency while keeping a fixed duty cycle). You will also need to use independent timers if you want to control the phase offset between outputs (e.g.. to commutate a motor), but I think you would be much better off doing that using some of the STM timer advanced features that are not supported by the mbed API.
3) By design, the mbed API does not really get into hardware specific issues. It also tends to be NXP-centric, so hardware aspects specific to STM MCUs may not get a lot of coverage. STM has some excellent documentation, but it can be a bit difficult to determine where to find information on a specific topic. AN4013 "STM32 cross-series timer overview" is a good place to start for a general explanation of the various timer features. AN4776 "General-purpose timer cookbook" is another good STM timer reference. As suggested in Bill Bellis’ response, the reference manuals for the specific MCUs on your boards (RM0368 for the MCU on the Nucleo-F401RE board and RM0390 for the MCU on the Nucelo-F446RE Board) have detailed descriptions of each timer and how to configure their registers. Finally, look at the examples in the STM32CubeF4 firmware package and its user manual UM1725. The examples for the STM32 446E_EVAL board include "TIM_Encoder" for processing quadrature encoder outputs and "TIM_PWMOutput" for generating four PWM waveforms, along with a number of additional timer examples.
To post an answer, please log in. | https://os.mbed.com/questions/78027/How-to-choose-PWN-output-pins/ | CC-MAIN-2017-39 | refinedweb | 1,246 | 72.76 |
class TwigExtension extends Extension
TwigExtension.
Returns the base path for the XSD files.
Returns the namespace to be used for this extension (XML namespace).
Returns the recommended alias to use in XML.
This alias is also the mandatory prefix to use when using YAML.
This convention is to remove the "Extension" postfix from the class name and then lowercase and underscore the result. So:
AcmeHelloExtension
becomes
acme_hello
This can be overridden in a sub-class to specify the alias manually.
Returns extension configuration.
Gets the annotated classes to cache.
Adds annotated classes to the class cache.
Loads a specific configuration.
© 2004–2017 Fabien Potencier
Licensed under the MIT License. | http://docs.w3cub.com/symfony~4.0/symfony/bundle/twigbundle/dependencyinjection/twigextension/ | CC-MAIN-2018-13 | refinedweb | 109 | 53.98 |
Versioning Service
• Mark Eschbach
Dealing with API drift is an interesting problem and a constant challenge on the mobile systems I’ve worked on. Following Postel’s Law our APIs should be reasonably accepting of incoming data and what they produce. A line must eventually be drawn somewhere though and there isn’t always a strong business case for supporting older versions. Sometimes this is motivated purely by user count while others it’s a shfit in serivce’s domain.
We’re begining to close out a major shift in our core domain model. For a young company this isn’t unusual however this is my first go around in a piviot. We’ve scoped API calls in Django under an increment version name, for example
api/v2 has now become
api/v3 for the path components. With this piviot we are forcing all clients to upgrade to use the new system. This leaves at least one path component which needs to remain under the
v2 namespace:
compatability. We’ve settled on aliasing the path at the current time to the new location of the resource interpreter but I’m left wondering if there is a better way.
In a world where I could build any system I please I suppose I would have an external service who coordinates availability as well as compatability. This would also allow for rolling updates without effecting older versions of the API. I’m sure this will come up and this is definitely not tempered through production support yet. Hopefully I’ll get a chance to distill this vaporware into a reall system in the near future. | http://meschbach.com/stream-of-consciousness/programming/2017/03/06-versions-and-business-logic/ | CC-MAIN-2018-13 | refinedweb | 273 | 61.16 |
I.
on said:
feed validator complains about the tag: uri in your feed, that could be the problem.
on said:
Sorry the original link was to the validation of your atom feed, but the url was mangled by the comment…so fv tracked down your rss feed and complained about it too! Original link was…
on said:
Yep, I’d noticed that. Strangely it complains if I don’t have it in there and I can’t see any difference between my feed and one of the
example feeds on. The problem was that planet doesn’t understand the <content type=”html”> mode where content is
escaped. I changed it to type=”xhtml” where content is xml and the child is a <div> with the xhtml namespace defined. It looks like it’s understood that and hasn’t displayed the markup.
I suspect planet.debian.org need to upgrade their copy of feedparser to one that understands atom 1.0 properly.
on said:
Any chance you could make the broken copy of the feed available (or just mail it to me)? It’d be interesting to try to track down the problem.
on said:
Of course I could have misunderstood the spec.
on said:
Not your fault at all… it turns out even the latest planet doesn’t grok atom 1.0, its still got the old feedparser bundled. I dropped in the latest feedparser and it ‘just worked’. I’ll pass this on to -devel. Thanks! | https://www.davidpashley.com/2006/03/19/atom-feed-and-planet/ | CC-MAIN-2020-05 | refinedweb | 247 | 82.24 |
I've gotten something that, as I run through it line by line, should work. However, I keep getting two error messages. In the console, I see:
File "python", line 7
else:
^
SyntaxError: invalid syntax
Meanwhile, in the editor, I see this:
Oops, try again. Did you create a function called censor? Your code threw a "global name 'censor' is not defined" error.
def censor(text, word): words_arr = text.split() final = '' for check_word in words_arr: if(check_word == word): final.join(" " + "*" * (len(check_word)) else: final.join(check_word) return final censor("I like apples and oranges and bananas", "and")
Admittedly, there's a pretty good chance that this is just my bonehead forgetting something simple about conditionals, but can someone please help me because I can't figure out for the life of me what it is. | https://discuss.codecademy.com/t/error-with-else-statement-in-censored/43310 | CC-MAIN-2018-34 | refinedweb | 135 | 65.93 |
On 09/03/2011 08:44 AM, Andreas Färber wrote:
Am 02.09.2011 um 17:40 schrieb Anthony Liguori:On 08/29/2011 09:55 AM, Anthony Liguori wrote:This has been discussed before in the past. The special casing really makes no sense anymore. This seems like a good change to make for 1.0. Signed-off-by: Anthony Liguori<address@hidden>Applied. Regards, Anthony Liguori--- Makefile | 5 ++--- Makefile.target | 4 ---- 2 files changed, 2 insertions(+), 7 deletions(-) diff --git a/Makefile b/Makefile index 8606849..51ecdb5 100644 --- a/Makefile +++ b/Makefile @@ -365,9 +365,8 @@ tar: rm -rf /tmp/$(FILE) SYSTEM_TARGETS=$(filter %-softmmu,$(TARGET_DIRS)) -SYSTEM_PROGS=$(patsubst qemu-system-i386,qemu, \ - $(patsubst %-softmmu,qemu-system-%, \ - $(SYSTEM_TARGETS))) +SYSTEM_PROGS=$(patsubst %-softmmu,qemu-system-%, \ + $(SYSTEM_TARGETS)) USER_TARGETS=$(filter %-user,$(TARGET_DIRS)) USER_PROGS=$(patsubst %-bsd-user,qemu-%, \ diff --git a/Makefile.target b/Makefile.target index 07af4d4..29287ed 100644 --- a/Makefile.target +++ b/Makefile.target @@ -27,12 +27,8 @@ ifdef CONFIG_USER_ONLY QEMU_PROG=qemu-$(TARGET_ARCH2) else # system emulator name -ifeq ($(TARGET_ARCH), i386) -QEMU_PROG=qemu$(EXESUF) -else QEMU_PROG=qemu-system-$(TARGET_ARCH2)$(EXESUF) endif -endif PROGS=$(QEMU_PROG) STPFILES=This will leave an old qemu executable from a previous `make install` behind.
You're not supposed to do a make install on top of another install. You're supposed to first do a make uninstall in the old tree than a make install in the new tree.You're not supposed to do a make install on top of another install. You're supposed to first do a make uninstall in the old tree than a make install in the new tree.
Semantically, this is how a distro package upgrade works.
We should check for it and, unless it's a symlink to qemu-system-i386, remove it in the install target.
Once we're no longer generating an executable, we should be removing it from the system.Once we're no longer generating an executable, we should be removing it from the system.
It's up to the user to remove old files from the system. Regards, Anthony Liguori
Andreas | https://lists.gnu.org/archive/html/qemu-devel/2011-09/msg00449.html | CC-MAIN-2020-34 | refinedweb | 343 | 50.02 |
Using Borland 4.5
I think I got most the program done but its hard for me to setup functions with returning names and values.
Problems States:
Winning Division:
Write a program that determines which of a company's four divisions (Northeast, Southeast, Northwest, and Southwest) had the greatest sales for a quarter. It should include the following two functions that are called by main.
-double getSales()is passed the name of a division. It ask the user for a division's quarterly sales figure, validates the input then returns it. It should be called once for each division.
-void findHighest() is passed the four sales totals. It determines which is the figure largest and prints the name of the high grossing division, along with its sales figures.
Input Validation: Do not accept dollar amounts less than $0.00
I really don't understand the first function that is underlined.
This is what I have so far.
#include <iostream.h> #include <iomanip.h> #include <stdlib.h> double getSales(double, double, double, double); void findHighest(double, double, double, double); int main() { double Neast, Seast, Nwest, Swest; cout << "This program determines which of a company's four divisions had " ; cout << "greatest sales for a quarter." << endl; cout << "Northeast Division: " << endl; Neast = getSales(); cout << "Southeast Division: " << endl; Seast = getSales(); cout << "Northwest Division: " << endl; Nwest = getSales(); cout << "Southwest Division: " << endl; Swest = getSales(); findHighest(); } double getSales() { double sales; cout << "What is the sales for this division?" << endl; cin >> sales; if(sales < 0) { cout << " Error: Only enter sale figures above zero" << endl; exit(0); } return sales; void findHighest(double Neast, double Seast, double Nwest, double Swest) { cout << setiosflags(ios::showpoint | ios::fixed); cout << setprecision(2); if (Neast > Seast && Neast > Nwest) { if(Neast > Swest) { cout << "The Northeast division had the greatest number of sales, $"; cout << Neast << endl; } } if (Seast > Neast && Seast > Nwest) { if(Seast > Swest) { cout << "The Southeast division had the greatest number of sales, $"; cout << Seast << endl; } } if (Nwest > Neast && Nwest > Seast) { if(Nwest > Swest) { cout << "The Northwest division had the greatest number of sales, $"; cout << Nwest << endl; } } if <Swest > Neast && Swest > Seast) { if(Swest > Nwest) { cout << "The Southwest divsion had the greatest number of sales, $"; cout << Swest << endl; } } } | https://www.daniweb.com/programming/software-development/threads/331961/why-are-functions-so-confusing-hw-help | CC-MAIN-2018-13 | refinedweb | 363 | 59.64 |
Some countries and languages standardize on number and date formats that don't translate smoothly between cultures. It is important for C++/Windows developers to have strategies and techniques to handle this challenge and other challenges presented by diverging sets of localization API functions. The CtrSynch sample app illustrates how to keep the Windows API locale in synch with the C-runtime (CRT) locale so that functions like LoadString are in step with conversion routines like _tprintf.
LoadString
_tprintf
Have you ever encountered a situation where you need to read a double/floating point value from text formatted in another locale? For example, the number 1023.54 displays in English-US as 1,023.54 and in German-Germany as 1.023,54. This problem comes up often when sharing text-based information generated in Europe (Germany, France, Spain) and consumed in the US. The reverse is also true.
Say, a German company exports a Tab Separated text (TSV) file from a spreadsheet on a workstation running in the German-Germany locale. The file is emailed to an American firm, where values like 1.023,54 import as a decimal number between 1 and 2 rather than 1023. This is a very common scenario.
The first step in properly transferring double values (or dates formatted by locale defaults) is to include a locale identifier in the data. This can be accomplished using a file header, an LCID field in each data row, embedded logic in the file name, and so on. In my simple example, I just wrote a method to pack an LCID onto the end of the string containing the number. Conversely, I wrote a routine to parse it back out before reading the number. The final issue is the actual conversion of the text to doubles. My first instinct was to run SetThreadLocale, run the _tcstod function on the text, then return to the previous thread locale.
SetThreadLocale
_tcstod
It doesn't work! I spent a lot of time trying to figure this out, and I hope to save you the effort!
It turns out, the C-runtime routine _tcstod (strtod in ANSI, wcstod in UNICODE) gets its locale context from the C-runtime function setlocale. SetThreadLocale does not talk to setlocale. Therefore, calling SetThreadLocale without calling setlocale puts you in a situation where LoadString will load from the current thread locale, but _tprintf will format in the locale the application started under. So, should you just call setlocale at the same time you call SetThreadLocale?
strtod
wcstod
setlocale
Well, I wish it was that simple! Here is what must happen in your code to keep the thread locale in step with the CRT's locale:
SetThreadLocale(1033);
setlocale(LC_ALL, "English_USA.1252");
You probably see the problem -- the two functions consume very different input parameters. After struggling with this, I found the solution is actually quite simple. It just required digging in the Windows API a bit. setlocale has two parameters, and the second is a three token string. The first is a language, the second is a country or region, and the third is a code page identifier. It turns out, these three values are readily acquired through the Windows API GetLocaleInfo. Therefore, given an LCID value, one may call GetLocaleInfo to find its language name (in English), it's region (in English), and its code page. A snippet:
GetLocaleInfo
LPCTSTR CCrtLocaleSwitch::loadLocaleId(LCID lcid, _bstr_t& bstrRetBuf)
{
TCHAR arcBuf[128];
memset(arcBuf, 0, sizeof(arcBuf));
//We should check the return code, but skipped for brevity...
GetLocaleInfo( lcid, LOCALE_SENGLANGUAGE, arcBuf, 127);
bstrRetBuf = arcBuf;
memset(arcBuf, 0, sizeof(arcBuf));
GetLocaleInfo( lcid, LOCALE_SENGCOUNTRY, arcBuf, 127);
if( *arcBuf )
{
bstrRetBuf += TEXT("_");
bstrRetBuf += arcBuf;
}
memset(arcBuf, 0, sizeof(arcBuf));
if( (GetLocaleInfo( lcid, LOCALE_IDEFAULTANSICODEPAGE, arcBuf, 127)
|| GetLocaleInfo( lcid, LOCALE_IDEFAULTCODEPAGE, arcBuf, 127))
&& *arcBuf )
{
bstrRetBuf += TEXT(".");
bstrRetBuf += arcBuf;
}
return bstrRetBuf;
}
The function above creates the string that is acceptable for setlocale. This allows you to keep the C-runtime's locale in synch with the Windows API locale state.
One final note regarding the sample application -- the sample classes are designed to restore state when they go out of scope. Regardless of how you exit a function, whether it's a normal return or an exception event, the previous locale will be restored. For brevity, I did not always check return values when calling Windows API or CRT functions, so please bear with my laziness!
return
The sample application was written in Visual C++ 7.1. The two main reusable classes, CTempLocale and CSmartBuf, should be compatible with other compilers. The simplest way to use these classes is to put them in a folder in your header file search path, then add the following to your stdafx.h file:
CTempLocale
CSmartBuf
#include <comdef.h>
#include <TempLocale.h>
The application itself is rather useless, but it illustrates keeping the CRT in synch with the Windows thread locale. When you select a new culture on the left, the window caption changes to "Hello World" in the selected language. Since MFC's CString internally calls LoadString, this functionality gets its locale from the Windows SetThreadLocale function. At the time the caption changes, the number in the lower left is reformatted per the selected locale, and that formatting gets its locale from the last call to the CRT setlocale function. On the right, you can select a target culture to translate the displayed number into, and it is displayed in the lower right. This lower-right number illustrates one possible way to attach LCID info to text containing a decimal number.
CString
The Windows API provides routines to load resources in the current thread's locale. The CRT provides routines to convert numbers to text and back again. The two sets of APIs don't share a locale status; therefore, C++ developers must build a way to keep them in synch. This article demonstrated a way to handle this task.. | https://www.codeproject.com/Articles/9600/Windows-SetThreadLocale-and-CRT-setlocale?fid=153420&df=10000&mpp=10&sort=Position&spc=None&tid=3675084 | CC-MAIN-2017-34 | refinedweb | 982 | 54.42 |
I'm trying to create a function that iterates through a string, finds characters that match to keys in a dictionary and replaces that character with the value in the dictionary for that key. However it currently only replaces first occurrence of a letter that is in the dictionary and stops there, where am I going wrong?
d = {
'I':'1', 'R':'2', 'E':'3', 'A':'4', 'S':'5', 'G':'6', 'T':'7', 'B':'8', 'O':'0',
'l':'1', 'z':'2', 'e':'3', 'a':'4', 's':'5', 'b':'6', 't':'7', 'g':'9', 'o':'0',
}
def cypher(string):
for i in string:
if i in d:
a = string.replace(i,d[i])
return a
You are prematurely ending your code with the call to
return within the for loop. You can fix it by storing your new string outside of the loop, only returning once the loop is done:
def cypher(string): a = string # a new string to store the replaced string for i in string: if i in d: a = a.replace(i, d[i]) return a
There is something wrong about the logic too, though. If you have a value in your dictionary that is also a key in the dictionary, the key may get replaced twice. For example, if you have
d = {'I': 'i', 'i': 'a'}, and the input is
Ii, your output would be
aa.
Here's a much more concise implementation using
join that does not have this problem.
def cypher(string): return ''.join(d.get(l, l) for l in string) | https://codedump.io/share/QD8Q9cAGnbQM/1/replace-multiple-characters-in-string-with-value-from-dictionary-python | CC-MAIN-2017-43 | refinedweb | 256 | 76.25 |
At the highest level, the analyze_tar_function() function opens the .tar file, processes each file inside by calling add_tar_entry(), and then closes the .tar file. There's a wonderful library called zlib, which lets us open even compressed files and pretend that they are just normal, uncompressed files. That's what gives us the flexibility to open either a .tar or a .tar.gz file with no additional work on our part. (The limitation of the library is that seeking may be slow, because decompression may need to occur.)
int analyze_tar_file (cfs_attr_t *a, char *fname) { gzFile fd; off_t off; ustar_t t; int size; int sts; char *f; // 1) the .tar (or .tar.gz) file must exist :-) if ((fd = gzopen (fname, "r")) == NULL) { return (errno); } off = 0; f = strdup (fname); // 2) read the 512-byte header into "t" while (gzread (fd, &t, sizeof (t)) > 0 && *t.name) { dump_tar_header (off, &t); // 3) get the size sscanf (t.size, "%o", &size); off += sizeof (t); // 4) add this entry to the database if (sts = add_tar_entry (a, off, &t, f)) { gzclose (fd); return (sts); } // 5) skip the data for the entry off += ((size + 511) / 512) * 512; gzseek (fd, off, SEEK_SET); } gzclose (fd); return (EOK); }
The code walkthrough is:
In step 5 we skip the file content. I'm surprised that not all of today's tar utilities do this when they're dealing with files — doing a tar tvf to get a listing of the tar file takes forever for huge files! | http://www.qnx.com/developers/docs/qnxcar2/topic/com.qnx.doc.neutrino.cookbook/topic/s2_tarfs_analyze_tar_file.html | CC-MAIN-2022-27 | refinedweb | 246 | 68.4 |
Rule Based Matching in Spacy
Rule based matching is a very useful feature in Spacy. It allows you to extract the information in a document using a pattern or a combination of patterns.
I will use the Obama speech in as illustration. I would like to extract the number of times Obama said “America” in this speech. You can use rule based matcher in Spacy to parse the text and extract the information as follows:
Output:Output:
from spacy.matcher import Matcher nlp = spacy.load("en_core_web_sm") matcher = Matcher(nlp.vocab) pattern = [{"TEXT": "America"}] matcher.add("Obama",[pattern]) text = open('obama.txt').read() doc = nlp(text) matches = matcher(doc) count = 0 for _ in matches: count = count +1 print("No of times Obama used America is ",count)
No of times Obama used America is 10
References:
Relevant Courses
May 23, 2021 | https://www.tertiaryinfotech.com/rule-based-matching-in-spacy/ | CC-MAIN-2022-21 | refinedweb | 140 | 58.79 |
01
Sergey Babkin writes:
> The rest of ttf2pt1 uses a 3-clause BSD license. But I don't
> see any problems with subsections being GPLed.
I took this another round on fedora-legal-list. The conclusion is
that since the GPL-licensed scripts are really separate programs, just
communicating with ttf2pt1 via data files, there isn't strictly any
problem here.
But that is only because they are not parts of the same program. The
advertising clause in your BSD license is not compatible with the GPL.
() So a
suggestion I'd like to forward from fedora-legal is to drop the
advertising clause. It's up to you, of course, but that way there
would be no doubt about compatibility.
Sergey Babkin writes:
> The rest of ttf2pt1 uses a 3-clause BSD license. But I don't
> see any problems with subsections being GPLed.
What Tom "spot" Callaway said on fedora-legal-list was this:
> So, the problem here is that the BSD license has the advertising clause,
> which makes it incompatible with GPL. You will need to get the copyright
> holders of the code under that BSD license to drop the advertising
> clause.
Sergey Babkin <babkin@...> さんは書きました:
>.
>
> I guess, since they are in separate files, this should not be an issue?
> AFAIK there is nothing in GPL that prevents packaging together with files under BSD
> license?
>
>.
>
> That must be an oversight. As far as I can tell, they should be
> covered by the GPL, just as the rest of the code contrinuted by SuSE.
> Maybe Mike can comment on this.
Yes, this is just an oversight.
It should be free software. I think GPL is OK. Or do you think any
other license would be more appropriate? Of course I want this
to be free software and convenient to use and package for you.
>>Would it be possible to sort out these licensing issues? And maybe
>>even issue an updated package?
>
> Maybe :-) I'm pretty sure it could use an update to some more recent FreeType too :-)
>
> -SB
>
--
Mike FABIAN <mfabian@...>
睡眠不足はいい仕事の敵だ。
I � Unicode
Sergey Babkin writes:
> I guess, since they are in separate files, this should not be an
> issue? AFAIK there is nothing in GPL that prevents packaging
> together with files under BSD license?
That was a quick reply! I thought this project was pretty dormant.
But that doesn't mean the people are dormant, I guess. :-)
Seriously, according to
the BSD advertising clause is incompatible with the GPL. Maybe that's
because I posed my question badly. I followed up with a question if
it would help to exclude the GPL program from the produced package.
Maybe there isn't a problem at all. I certainly don't claim to
understand all the bits and pieces of these licensing issues. (Who
does?)
> I'm pretty sure it could use an update to some more recent FreeType too :-)
:-) Last I built I used this trivial patch to be able to build with a
bit later FreeType:
--- ft.c~ 2003-12-31 22:30:50.000000000 +0100
+++ ft.c 2004-09-05 22:46:07.000000000 +0200
@@ -12,11 +12,12 @@
#include <stdlib.h>
#include <ctype.h>
#include <sys/types.h>
-#include <freetype/freetype.h>
-#include <freetype/ftglyph.h>
-#include <freetype/ftsnames.h>
-#include <freetype/ttnameid.h>
-#include <freetype/ftoutln.h>
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include FT_GLYPH_H
+#include FT_SFNT_NAMES_H
+#include FT_TRUETYPE_IDS_H
+#include FT_OUTLINE_H
#include "pt1.h"
#include "global.h".
Would it be possible to sort out these licensing issues? And maybe
even issue an updated package?.
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I agree to receive quotes, newsletters and other information from sourceforge.net and its partners regarding IT services and products. I understand that I can withdraw my consent at any time. Please refer to our Privacy Policy or Contact Us for more details | https://sourceforge.net/p/ttf2pt1/mailman/ttf2pt1-users/ | CC-MAIN-2017-26 | refinedweb | 1,250 | 75.2 |
Ticket #283 (new defect)
PyYaml does not create logging handler classes correctly in Python 2.7
Description
logging.FileHandler? and logging.RotatingFileHandler? (haven't tried other handlers) do not get correctly initialized in python 2.7 when loaded using PyYaml?.
This example reproduces the problem:
import logging import logging.handlers import yaml logger = logging.getLogger() # root logger # Option 1 - OK ##handler = logging.handlers.RotatingFileHandler(filename = "test.log", maxBytes = 262144, backupCount = 3) # Option 2 - RotatingFileHandler fails when created through yaml handler = yaml.load(""" !!python/object/new:logging.handlers.RotatingFileHandler kwds: filename: test.log maxBytes: 262144 backupCount: 3 """) # Option 3 - FileHandler also fails when created through yaml ##handler = yaml.load(""" ##!!python/object/new:logging.FileHandler ## kwds: ## filename: test.log ##""") logger.addHandler(handler) logger.warning("test handler")
The example above works in python 2.6 and 2.5, but fails in python 2.7. In both cases I am using the latest version of PyYaml?: 3.10
I've opened a ticket in python () and it seems that Logging changed from old-style classes in 2.6 to new-style classes in 2.7 and that may be the reason.
Change History
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Planning Council/December 01.
- After the meeting, Pascal mentioned to to me in email that m2e might be delayed due to waiting for some CQs. He should know more next week.
Indigo Plan and Schedule
- Discuss "namespace" issues discussed in bug 330312 and elsewhere.
- Several issues came up: One, more concerned with EDP proposed changes, rather than sim. rel., is that some projects do not use the "org.eclipse" namespace through out ... ETF and AspectJ. That is, there are known exceptions. The issue for Sim. Rel has more to do with "overlapping" or "reusing" someone else's namespace, especially in a common repository.
- While it was acknowledged that "it has happened once", the general feeling of the council was that it is so rare, that rules and procedures did not need to be documented. That is was indeed "common sense" that you can not use someone else's namespace, and we do not need to document such common knowledge or such rare exceptional cases.
- Discuss issue (from last year) ... to what extent should Sim. Rel. materials (checklist) be part of official release docuware.
- It was felt we did not need the "persistence" of a PDF copy and that a link would be nice, but no hard requirement. So, I added this sentence:
"This may be in the form of providing a URL to the checklist, ideally as part of the normal docuware."
- following the original statement:
"In addition to the ordinarily required Release Review Archival Materials, all Projects participating in yearly Release agree to provide a checklist-with-detail form that describes their compliance (or not) with all of the criteria items described in this document."
-?
-.
- It was requested to beef up the "communication" aspect better, that if a project is going to drop out, or suspend activities for a long time, they should announce broadly since could effect dependent projects.
-: the question of "3.7 or 4.1" came up again ... I should add a FAQ item
- | http://wiki.eclipse.org/Planning_Council/December_01_2010 | CC-MAIN-2016-50 | refinedweb | 328 | 74.9 |
01 December 2011 18:29 [Source: ICIS news]
(updates with Canadian and Mexican chemical railcar traffic data)
?xml:namespace>
Canadian chemical railcar loadings for the week totalled 10,518, up from 9,835 in the same week a year earlier, the Association of American Railroads (AAR) said.
The previous week ended 19 November saw a year-on-year increase 2.3% in Canadian chemical railcar shipments.
The weekly chemical railcar loadings data are seen as an important real-time measure of chemical industry activity and demand.
Year to date to 26 November, Canadian chemical railcar shipments were up by 9.1% to 522,419.
The AAR said chemical railcar traffic in
Year to date to 26 November, Mexican chemical railcar shipments were up by 6.5% to 55,175.
There were 24,504 chemical railcar loadings last week, compared with 25,079 in the same week in 2010. In the previous week ended 19 November,
Meanwhile, overall
For all | http://www.icis.com/Articles/2011/12/01/9513308/canada-weekly-chemical-railcar-traffic-rises-6.9.html | CC-MAIN-2015-22 | refinedweb | 159 | 58.08 |
Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
I figured out how to do it.
It's fairly simple. I just have to reassing the pointvalues after the Update
so if I insert a new
puntenLijst = op.GetAllPoints()
testPnt = puntenLijst[0]
the 'testPnt' has updated values.
The samples under the GetUserDataContainer () and RemoveUserData seem to be other way around. Not a big deal but..
I saved to a different directory and made shure that nothing was write protected, but still the "APPEND" mode throws an error.
Apparantly the file gets saved as a read-only file.
if I replace the mode = c4d.FILEOPEN_WRITE with c4d.FILEOPEN_APPEND in the example as given in the SDK documentation I get a "cannot open file to write"- error.
What am I doing wrong? It works fine with the "mode = c4d.FILEOPEN_WRITE "
and after running this I get:
@stevejlv I found a workaround: the value part in the value;string Cycle option list does not have to be 0,1,2 etc.
So I can give them the exact value as the string part (as long as they are int) and get the value I want the old fashioned way: [c4d.ID_USERDATA,1]
@s_bach Thanks for your reply, So I guess there is no 'easy' way to get the label value.
I was working in a Python Generator's Object code and so filed my question under Python, my bad.
I'll try to get it right with my next question.
and yes I meant this one:
To get the USERDATA from op we simply use, for instance: op[c4d.ID_USERDATA,7]
this will give us the value from the chosen option index (7) in my USERDATA
Data Type : Integer, Interface : Cycle
To get to the 'str' value which corresponds to this Option I constructed the following code:
op.GetUserDataContainer()[8][c4d.DESC_NAME].GetContainer(c4d.DESC_CYCLE).GetString(op[c4d.ID_USERDATA,7])
it works but this seems to me like a little overkill (understatement)
Is there a better/ correct way to get to the 'str'-value. Also I have to know the position in the GetUserDataContainer() (in my case [8]) to get to the value.
op.GetUserDataContainer()[8][c4d.DESC_NAME].GetContainer(c4d.DESC_CYCLE).GetString(op[c4d.ID_USERDATA,7])
Hello, I try to manipulate a polygon point in Python with the SetPoint() command.
So for instance I want to double the Values for X,Y en Z of point[0] = testPnt (for instance Vector(1,1,1))
I use the values of the point to double them. (I used the '×' to indicate multiplication the '*' messes up the post)
op.SetPoint(0,c4d.Vector(testPnt.x×2,testPnt.y×2,testPnt.z×2))
If later somewhere else in my code I change these values again, say I triple them
op.SetPoint(0,c4d.Vector(testPnt.x×3,testPnt.y×3,testPnt.z×3))
and print the values I still get the unchanged values. i.e. Vector(1,1,1)
I want to get (6,6,6) at the end.
Here my testing code:
def main():
op = doc.GetActiveObject() #select a polygon object with Point[0] at (1,1,1) as example
puntenLijst = op.GetAllPoints()
testPnt = puntenLijst[0]
print 'pnt0 at start: ' ,testPnt # check the coordinates before manipulation
*#prints: pnt0 at start: Vector(1,1,1) ok*
op.SetPoint(0,c4d.Vector(testPnt.x*2,testPnt.y*2,testPnt.z*2))
print 'pnt0 after SetPoint:' ,testPnt
*#prints: pnt0 after SetPoint: Vector(1,1,1) not ok, got to send Message(c4d.MSG_UPDATE)*
op.Message (c4d.MSG_UPDATE)
print 'pnt0 after MSG_UPDATE' ,testPnt
*#prints: pnt0 after MSG_UPDATE: Vector(1,1,1) not ok, got to do the c4d.EventAdd()*
c4d.EventAdd()
print 'pnt0 after c4d.EventAdd():' ,testPnt
*#prints: pnt0 after c4d.EventAdd(): Vector(1,1,1) not ok, got to do ??*
op.SetPoint(0,c4d.Vector(testPnt.x*3,testPnt.y*3,testPnt.z*3))
print testPnt
# hoping for Vector(6,6,6) but nope got Vector(1,1,1)
finaly in the Structure Manager after running this code the point has coordinates (3,3,3) and not (6,6,6) the last SetPoint used the startingpoint(1,1,1) and I want to continue with the changed values i.e. (2,2,2) | https://plugincafe.maxon.net/user/stevejlv | CC-MAIN-2022-27 | refinedweb | 738 | 56.55 |
Aside from the most basic of Android applications, everything you build will require at least some use of background threading to perform an operation. This is because Android has something known as an ANR (Application Not Responsive) timeout, which is caused when an operation takes five seconds or longer on the UI thread, preventing user input and causing what appears to the user to be a hanging app.
In order to avoid this, you must move longer running operations, such as network requests or slow database queries, to a different thread so as to not prevent the user from continuing to use your app. Although comprehensive coverage of threading is a large and complex subject in computer science, this tutorial will introduce you to the core concepts of threading in Android, and to some of the tools available to help you build apps that perform better by using background processes.
Do you find it easier to learn with video? Why not check out our course:
Understanding Threading
When an application is launched, a new Linux process with a single main execution thread is started. This is the thread that has access to the Android UI toolkit, listens for user inputs, and handles drawing to the Android device screen. Because of this, it is also commonly referred to as the UI thread.
All components of an application run within the same thread and process by default, though additional threads can be created to move tasks off the UI thread and prevent an ANR. When it comes to threading in Android, there are two simple rules to remember to keep your app functioning as expected:
- Do not block the UI thread.
- Do not attempt to access Android UI components from outside the UI thread.
While you can comply with the first rule by simply creating a new
Thread and
Runnable, handling the second rule gets a little more tricky. Consider the following code snippet:
new Thread(new Runnable() { public void run() { try { Thread.sleep(6000); } catch( InterruptedException e ) { } mTextView.setText("test"); } }).start();
While this code won't stall the UI thread while the thread sleeps past the ANR timeout, attempting to set the
TextView text will cause the app to throw the following error:
android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
Luckily, there are a few simple ways to get around this. You can use Android's
runOnUiThread(Runnable) method to execute code back on the app's main thread.
mTextView = (TextView) findViewById(R.id.text); new Thread(new Runnable() { public void run() { try { Thread.sleep(6000); } catch( InterruptedException e ) { } runOnUiThread(new Runnable() { @Override public void run() { mTextView.setText("test"); } }); } }).start();
Or you can take a standard
View object and
Runnable to it.
new Thread(new Runnable() { public void run() { try { Thread.sleep(6000); } catch( InterruptedException e ) { } mTextView.post(new Runnable() { @Override public void run() { mTextView.setText("test"); } }); } }).start();
While both of these tricks will help make your operations thread safe, as your application gets more complex this will become cumbersome to maintain.
AsyncTask
One of the tools provided by Android to help manage complexity with background threads is
AsyncTask.
AsyncTask provides a worker thread for blocking operations, and then posts a result back to the UI thread with a pre-created callback method, allowing you to get your tasks done easily without having to fumble with threads and handlers.
AsyncTask Lifecycle.
When you create an
AsyncTask class, you must override these generics in both the class declaration and in the above methods. An example
AsyncTask that updates a
ProgressBar every second can be seen here:
protected class DemoAsyncTask extends AsyncTask<Integer, Void, String> { @Override protected void onPreExecute() { super.onPreExecute(); mProgress.setProgress(0); mProgress.setVisibility(View.Visible); } @Override protected void onProgressUpdate(Integer... values) { super.onProgressUpdate(values); mProgress.setProgress(values[0]); } @Override protected Void doInBackground(Void... params) { for( int i = 0; i < 100; i++ ) { try { Thread.sleep(1000); } catch( InterruptedException e ) {} publishProgress(i); } return "All done!"; } @Override protected void onPostExecute(String result) { super.onPostExecute(aVoid); if( isCancelled() ) { return; } mProgress.setVisibility(View.GONE); Toast.makeText(context, result, Toast.LENGTH_SHORT).show(); } }
You may have noticed that
onPostExecute(T) checks against
isCancelled(). This is because there is one large issue with
AsyncTasks: they maintain a reference to a
Context even after that
Context has been destroyed.
This is most easily seen).
As with anything in programming, the answer to when you should use an
AsyncTask is: it depends. While
AsyncTasks are simple to use, they aren't a be-all and end-all solution to threading, and are best used for short operations lasting at the most a few seconds. If you have an operation that may last longer, I recommend that you investigate using
ThreadPoolExecutor,
Service, or
GcmNetworkManager (a backwards compatible version of the
JobScheduler).
Services
When you need to perform a long-running operation in the background, such as playing music, performing network transactions, or interacting with a content provider, you may want to consider using a
Service. A basic
Service can exist in two states: started and bounded.
A started
Service is kicked off by a component in your application and remains active in the background of the device, even if the original component is destroyed. When the task that a started
Service is performing has completed, the
Service will stop itself. A standard started
Service is generally used for long-running background tasks that do not need to communicate with the rest of the app.
A bound
Service is similar to a started
Service, and it also provides callbacks for various app components that can bind to it. When all bound components have unbound themselves from the
Service, it will stop itself. It is important to note that these two ways to run a
Service are not mutually exclusive—you can start a
Service that will run indefinitely and can have components bind to it.
IntentService
One of the largest issues with a standard
Service is that it cannot handle multiple requests at a time, as this would be a multi-threading nightmare. One way around this is to extend an
IntentService, which extends a standard
Service. The
IntentService creates a default worker thread for executing all intents that are received in
onStartCommand(), so all operations can happen off the main thread. It then creates a work queue for sending each intent to
onHandleIntent() one at a time so that you don't need to worry about multi-threading issues.
Aside from handling threading,
IntentService also stops itself automatically once all start requests have been handled. Because all of the implementation details are handled in
IntentService, the work for you as a developer is fairly straightforward.
public class ExampleIntentService extends IntentService { //required constructor with a name for the service public ExampleIntentService() { super("ExampleIntentService"); } @Override protected void onHandleIntent(Intent intent) { //Perform your tasks here try { Thread.sleep(5000); } catch (InterruptedException e) {} } }
Conclusion
In this tutorial, you've learned a lot about threading and multi-threading solutions in Android. Entire books have been written on threading in Android, but you should now have enough of a foundation to code general tasks and understand more in-depth documentation for your more complex Android applications down the line.
><< | https://code.tutsplus.com/tutorials/android-from-scratch-background-operations--cms-26810?ec_unit=translation-info-language | CC-MAIN-2021-04 | refinedweb | 1,202 | 52.39 |
Programs often need objects that can act as a flag to indicate a 1 or 0 value, or a true or false state. There are several objects suitable for this task when you are using the MPLAB® XC Compilers, and these objects are explained in the following sections and summarised in the table at the end of this article.
Boolean objects
The _Bool type is a standard C type available when using the C99 or later C standard. Use the <stdbool.h> header file when using this type, which allows you to use macros like true and false for the values held by these objects.
_Bool objects can be made any size by the compiler (provided they are able to store 0 and 1) however, many implementations allocate an entire byte for such objects, as is the case with all MPLAB XC compilers. You can determine the size of a _Bool object or type by using the sizeof() operator.
When any scalar value is converted to type _Bool, the result is 0 (false) if the value compares equal to 0; otherwise, the result is 1 (true). This conversion is markedly different from the usual integer conversion rules employed by the C language.
#include <stdbool.h> _Bool buttonDown; unsigned int state = 0x42; buttonDown = state; // buttonDown assigned 'true' (1) if(buttonDown == true) processRequest();
As with ordinary objects, you can take the address of _Bool objects and define pointers to such objects. Structure members can be defined as type _Bool, if required; however, you might consider using bit-fields in this situation, discussed in the next section.
_Bool * bp; struct { _Bool button1; _Bool button2; } buttonState; bp = &buttonDown; buttonState.button1 = *bp;
Bit-fields
Bit-fields are special objects that can be used only as members inside structures. They are available in all implementations of standard C (including C90), although some aspects of their operation are implementation-defined.
The number of bits allocated to a bit-field is specified when it is defined. To create a flag, allocate just a single bit to a bit-field by following the bit-field's name with :1. Bit-fields are packed into bytes, and as their placement in those bytes is strictly specified by the order in which they are defined in the structure, structures containing bit-fields are commonly used with unions to allow access to an entire byte (or bytes) and the bits which make up that byte (or bytes).
union { unsigned char byte; // a structure with 8 single bit bit-field objects, overlapping the union member "byte" struct { unsigned b0:1; unsigned b1:1; unsigned b2:1; unsigned b3:1; unsigned b4:1; unsigned b5:1; unsigned b6:1; unsigned b7:1; }; } byte_u; if(byte_u.byte = 0x10) // access the entire byte byte_u.b4 = 1; // access just one bit in that byte
Bit-fields are recognized as having an integer type. Conversions from scaler values wider than the bit-field are usually performed by truncating the higher-order bits in the value that are not represented in the bit-field destination. You cannot take the address of bit-field objects, nor define pointers to such objects, but you can perform these actions against the entire structure in which the bit-fields reside.
Bit Objects
The __bit type is a non-standard type implemented only by MPLAB XC8 when building for PIC devices, and hence projects using this type may not be portable to other projects or compilers. There are some restrictions on when objects of type __bit can be used, for example, they cannot be auto objects, but they can be qualified static, allowing them to be defined locally within a function.
__bit powerOn; int func(void) { static __bit flameOn; // ... }
These objects are always one bit in size, and you cannot specify a __bit object or type as the argument to the sizeof() operator. The XC8 compiler will pack 8 of these objects into one byte and access them using bit-orientated instructions, where possible.
The __bit type is an integer type (the signedness of single-bit objects does not make sense) so conversions from wider scaler values to __bit are performed by truncating all but the least significant bit in the value, potentially producing a different result to that obtained when assigning the same value to a _Bool.
__bit buttonDown; unsigned int state = 0x42; buttonDown = state; // buttonDown assigned 0 (false) if(buttonDown == 1) processRequest();
__bit objects are always represented by bit addresses (as opposed to conventional byte addresses), and bit addresses are shown for __bit objects and sections in list and map files. It is for this reason that you cannot take the address of __bit objects, nor can you define pointers to such objects. Structure members cannot be an object of type __bit.
Summary
The information in the above sections has been summarised in this table to help you select the best C type for your application. Check your favorite C language text or your compiler's user's guide for more information. | https://microchipdeveloper.com/c:bits-bools-and-bit-fields | CC-MAIN-2020-29 | refinedweb | 830 | 55.58 |
Optimization profile for dynamic input dimensions and shape tensors. More...
#include <NvInferRuntime.h>
Optimization profile for dynamic input dimensions and shape tensors.
When building an ICudaEngine from an INetworkDefinition thatEngine whenever.
Get the minimum / optimum / maximum dimensions for a dynamic input tensor.
If the dimensions have not been previously set via setDimensions(), return an invalid Dims with nbDims == -1.
Get the extra memory target that has been defined for this profile.
Get the number of values for an input shape tensor.
This will return the number of shape values if setShapeValues() has been called before for this input tensor. Otherwise, return -1.
Get the minimum / optimum / maximum values for an input shape tensor.
If the shape values have not been set previously with setShapeValues(), this returns nullptr.
Check whether the optimization profile can be passed to an IBuilderConfig object.
This function performs partial validation, by e.g. checking that whenever one of the minimum, optimum, or maximum dimensions of a tensor have been set, the others have also been set and have the same rank, as well as checking that the optimum dimensions are always as least as large as the minimum dimensions, and that the maximum dimensions are at least as large as the optimum dimensions. Some validation steps require knowledge of the network definition and are deferred to engine build time.
Set the minimum / optimum / maximum dimensions for a dynamic input tensor.
This function must be called three times (for the minimum, optimum, and maximum) for any network input tensor that has dynamic dimensions. If minDims, optDims, and maxDims are the minimum, optimum, and maximum dimensions, and networkDims are the dimensions for this input tensor that are provided to the INetworkDefinition object, then the following conditions must all hold:
(1) minDims.nbDims == optDims.nbDims == maxDims.nbDims == networkDims.nbDims (2) 0 <= minDims.d[i] <= optDims.d[i] <= maxDims.d[i] for i = 0, ..., networkDims.nbDims-1 (3) if networkDims.d[i] != -1, then minDims.d[i] == optDims.d[i] == maxDims.d[i] == networkDims.d[i]
This function may (but need not be) called for an input tensor that does not have dynamic dimensions. In this case, the third argument must always equal networkDims.
Set a target for extra GPU memory that may be used by this profile.
Set the minimum / optimum / maximum values for an input shape tensor.
This function must be called three times for every input tensor t that is a shape tensor (t.isShape() == true). This implies that the datatype of t is DataType::kINT32, the rank is either 0 or 1, and the dimensions of t are fixed at network definition time. This function must not be called for any input tensor that is not a shape tensor.
Each time this function is called for the same input tensor, the same nbValues must be supplied (either 1 if the tensor rank is 0, or dims.d[0] if the rank is 1). Furthermore, if minVals, optVals, maxVals are the minimum, optimum, and maximum values, it must be true that minVals[i] <= optVals[i] <= maxVals[i] for i = 0, ..., nbValues - 1. Execution of the network must be valid for the optVals.
Shape tensors are tensors that contribute to shape calculations in some way, and can contain any int32_t values appropriate for the network. Examples:
Tightening the minVals and maxVals bounds to cover only values that are necessary may help optimization. | https://docs.nvidia.com/deeplearning/tensorrt/api/c_api/classnvinfer1_1_1_i_optimization_profile.html | CC-MAIN-2022-40 | refinedweb | 564 | 56.05 |
01 June 2012 13:09 [Source: ICIS news]
LONDON (ICIS)--Russian mineral fertilizer producer Acron Group will next week hold meetings with shareholders in Zaklady Azoty Tarnow (ZAT) prior to a decision on whether to increase its bid for the Polish chemical group, Acron said on Friday.
Acron’s current offer for 66% of ZAT, totalling zlotych (Zl) Zl1.5bn ($422.5m, €342.5m), at a price of Zl36 per share, has been described as too low by ZAT and various shareholders, including pension fund AVIVA which owns a stake of 9%.
When originally announcing its offer to shareholders, Acron said it would go ahead with the purchase of shares in ZAT if shareholders owning 50% plus one share accepted its offer during the bid window, running from 6 June to 22 June.
However, Acron announced it has decided to increase the buy threshold to 66%.
All the unions with members at ZAT — ?xml:namespace>
They argue that Acron could use the ZAT name to develop openings for its own Russian fertilizer products in EU markets, while reducing fertilizer production at ZAT’s plants in
Acron, however, said it is intent on expanding the production of both itself and ZAT, while ZAT would also benefit from Acron’s access to cheaper feedstock materials.
The ZAT group produces nitrogen and multi-component fertilizers, caprolactam (capro), polyamide 6, oxo-alcohols, plasticisers and titanium dioxide (TiO2).
ZAT, which had 2011 revenues of Zl5.3 bn, is controlled by voting at the board level by
($1 = €0.81, $1 = Zl3.55, €1 = Zl | http://www.icis.com/Articles/2012/06/01/9566385/russias-acron-to-consider-increasing-offer-for-polands.html | CC-MAIN-2015-06 | refinedweb | 259 | 59.23 |
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