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# Autoload
This class creates a module table that will automatically call require to
find new keys. This enables "load as needed" code. If the required code
cannot be found, generates an error.
--]]------------------------------------------------------
local lub = require 'lub'
local lib = lub.class 'lub.Autoload'
local lib2 = {}
local private = {}
-- Declare a new table with autoloading feature. The `prefix` should reflect
-- the path used to call require for missing elements. If the optional `tbl`
-- is provided, this table will be used as starting content.
function lib.new(prefix, tbl)
assert(prefix, 'Missing prefix in Autoload call.')
local self = tbl or {}
self.type = prefix
return setmetatable(self, lib)
end
-- nodoc
function lib.__index(table, name)
-- Trying to load new lib like foo.Bar
local ok, new_lib_or_error = pcall(function() return require(table.type..'.'..name); end)
if ok then
-- insert new class with name in table
table[name] = new_lib_or_error
return new_lib_or_error
else
print(new_lib_or_error)
return nil
end
end
-- # Global
-- You can enable autoload on the global namespace `_G` to require modules.
--
-- WARN: You should not disable #strict or `nil` values in global namespace will
-- have a *huge* overhead (try to require code on every access).
-- Activate autoloading for global environment `_G` (this method is slightly
-- different then #new and adapted for the global environment). By default,
-- this uses #strict (forbids using global nil values).
function lib.global()
setmetatable(_G, lib2)
end
-- This can be used to disable strict mode when autoload is enabled for global
-- environment.
function lib.strict(x)
if x == false then
-- not strict
lib2.__index = private.__index
else
-- disable autoload and raise on nil
lib2.__index = private.__index_strict
end
end
--- Autoload for _G
function private.__index(table, name)
if name == '_PROMPT' or name == '_PROMPT2' then
-- special case for lua interactive
return nil
end
local ok, new_lib_or_error = pcall(function() return require(name); end)
if ok then
return new_lib_or_error or rawget(table, name)
else
-- nil value
return nil
end
end
--- Autoload for _G (strict mode = no nil allowed)
function private.__index_strict(table, name)
if name == '_PROMPT' or name == '_PROMPT2' then
-- special case for lua interactive
return nil
end
local ok, new_lib_or_error = pcall(function() return require(name); end)
if ok then
return new_lib_or_error or rawget(table, name)
else
-- nil value
error(string.format("Trying to access undefined global variable '%s'.\n%s", name, debug.traceback()))
end
end
-- Default is strict.
lib2.__index = private.__index_strict
return lib
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