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';
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'".
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.
The %options hash currently accepts one key, "-version". If you specify a version, then this subroutine will call "Class::Name->VERSION( $options{-version} )" internally, which will throw an error if the class's version is not equal to or greater than the version you requested.
This method will return the name of the class on success.
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.
Like "load_class", you can pass a "-version" in %options. If the version is not sufficient, then this subroutine will return false.
Like "load_class", you can pass a "-version" in %options. If the version is not sufficient, then this subroutine will return false.
If any one of the classes loads and passes the optional version check, that class name will be returned. If none of the classes can be loaded (or none pass their version check), then an error will be thrown.
If, when attempting to load a class, it fails to load because of a syntax error, then an error will be thrown immediately.
If the class exists, and it works, then it will return 1. If you specify a version in %options, then the version check must succeed or it will return 0.
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 (e.g.: a syntax error), then it will "croak" with that error.
This is useful for using if you want a fallback module system, i.e.:
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.
There is also a mailing list available for users of this distribution, at <http://lists.perl.org/list/moose.html>.
There is also an irc channel available for users of this distribution, at "#moose" on "irc.perl.org" <irc://irc.perl.org/#moose>.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.