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| # encoding: utf-8 | |
| """ | |
| Utilities for working with stack frames. | |
| """ | |
| #----------------------------------------------------------------------------- | |
| # Copyright (C) 2008-2011 The IPython Development Team | |
| # | |
| # Distributed under the terms of the BSD License. The full license is in | |
| # the file COPYING, distributed as part of this software. | |
| #----------------------------------------------------------------------------- | |
| #----------------------------------------------------------------------------- | |
| # Imports | |
| #----------------------------------------------------------------------------- | |
| import sys | |
| #----------------------------------------------------------------------------- | |
| # Code | |
| #----------------------------------------------------------------------------- | |
| def extract_vars(*names,**kw): | |
| """Extract a set of variables by name from another frame. | |
| Parameters | |
| ---------- | |
| *names : str | |
| One or more variable names which will be extracted from the caller's | |
| frame. | |
| **kw : integer, optional | |
| How many frames in the stack to walk when looking for your variables. | |
| The default is 0, which will use the frame where the call was made. | |
| Examples | |
| -------- | |
| :: | |
| In [2]: def func(x): | |
| ...: y = 1 | |
| ...: print(sorted(extract_vars('x','y').items())) | |
| ...: | |
| In [3]: func('hello') | |
| [('x', 'hello'), ('y', 1)] | |
| """ | |
| depth = kw.get('depth',0) | |
| callerNS = sys._getframe(depth+1).f_locals | |
| return dict((k,callerNS[k]) for k in names) | |
| def extract_vars_above(*names): | |
| """Extract a set of variables by name from another frame. | |
| Similar to extractVars(), but with a specified depth of 1, so that names | |
| are extracted exactly from above the caller. | |
| This is simply a convenience function so that the very common case (for us) | |
| of skipping exactly 1 frame doesn't have to construct a special dict for | |
| keyword passing.""" | |
| callerNS = sys._getframe(2).f_locals | |
| return dict((k,callerNS[k]) for k in names) | |
| def debugx(expr,pre_msg=''): | |
| """Print the value of an expression from the caller's frame. | |
| Takes an expression, evaluates it in the caller's frame and prints both | |
| the given expression and the resulting value (as well as a debug mark | |
| indicating the name of the calling function. The input must be of a form | |
| suitable for eval(). | |
| An optional message can be passed, which will be prepended to the printed | |
| expr->value pair.""" | |
| cf = sys._getframe(1) | |
| print('[DBG:%s] %s%s -> %r' % (cf.f_code.co_name,pre_msg,expr, | |
| eval(expr,cf.f_globals,cf.f_locals))) | |
| # deactivate it by uncommenting the following line, which makes it a no-op | |
| #def debugx(expr,pre_msg=''): pass | |
| def extract_module_locals(depth=0): | |
| """Returns (module, locals) of the function `depth` frames away from the caller""" | |
| f = sys._getframe(depth + 1) | |
| global_ns = f.f_globals | |
| module = sys.modules[global_ns['__name__']] | |
| return (module, f.f_locals) | |