NAME
Class::Load - a working (require "Class::Name") and more
SYNOPSIS
use Class::Load ':all';
try_load_class('Class::Name')
or plan skip_all => "Class::Name required to run these tests";
load_class('Class::Name');
is_class_loaded('Class::Name');
my $baseclass = load_optional_class('Class::Name::MightExist')
? 'Class::Name::MightExist'
: 'Class::Name::Default';
DESCRIPTION
require EXPR
only accepts Class/Name.pm
style module names, not Class::Name
. How frustrating! For that, we provide load_class 'Class::Name'
.
It's often useful to test whether a module can be loaded, instead of throwing an error when it's not available. For that, we provide try_load_class 'Class::Name'
.
Finally, sometimes we need to know whether a particular class has been loaded. Asking %INC
is an option, but that will miss inner packages and any class for which the filename does not correspond to the package name. For that, we provide is_class_loaded 'Class::Name'
.
FUNCTIONS
load_class Class::Name
load_class
will load Class::Name
or throw an error, much like require
.
If Class::Name
is already loaded (checked with is_class_loaded
) then it will not try to load the class. This is useful when you have inner packages which require
does not check.
try_load_class Class::Name -> 0|1 =head2 try_load_class Class::Name -> (0|1, error message)
Returns 1 if the class was loaded, 0 if it was not. If the class was not loaded, the error will be returned as a second return value in list context.
Again, if Class::Name
is already loaded (checked with is_class_loaded
) then it will not try to load the class. This is useful when you have inner packages which require
does not check.
is_class_loaded Class::Name -> 0|1
This uses a number of heuristics to determine if the class Class::Name
is loaded. There heuristics were taken from Class::MOP's old pure-perl implementation.
load_optional_class Class::Name -> 0|1
load_optional_class
is a lot like try_load_class
, but also a lot like load_class
.
If the class exists, and it works, then it will return 1.
If the class doesn't exist, and it appears to not exist on disk either, it will return 0.
If the class exists on disk, but loading from disk results in an error ( ie: a syntax error ), then it will croak
with that error.
This is useful for using if you want a fallback module system, ie:
my $class = load_optional_class($foo) ? $foo : $default;
That way, if $foo does exist, but can't be loaded due to error, you won't get the behaviour of it simply not existing.
SEE ALSO
- UNIVERSAL::require
-
Adds a
require
method toUNIVERSAL
so that you can sayClass::Name->require
. I personally dislike the pollution. - Module::Load
-
Supports
Class::Name
andClass/Name.pm
formats, notry_to_load
oris_class_loaded
. - Moose, Jifty, Prophet, etc
-
This module was designed to be used anywhere you have
if (eval "require $module"; 1)
, which occurs in many large projects.
AUTHOR
Shawn M Moore, <sartak at bestpractical.com>
The implementation of is_class_loaded
has been taken from Class::MOP.
BUGS
Please report any bugs or feature requests to bug-class-load at rt.cpan.org
, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Class-Load.
COPYRIGHT & LICENSE
Copyright 2008-2009 Best Practical Solutions.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.