

__END__

=pod

=head1 NAME

Mason::Manual::Plugins - Mason plugins

=head1 DESCRIPTION

A Mason plugin modifies behavior in one or more of Mason's main classes
simultaneously, using Moose roles. Many Mason features, even some that might be
considered "core", are implemented with plugins.

=head1 FINDING PLUGINS

By convention plugins live in the "Mason::Plugin::*" namespace, and plugin
bundles live in the "Mason::PluginBundle::*" namespace. You can find both with
this search:

    http://search.cpan.org/search?query=Mason%3A%3APlugin&mode=all

=head1 USING PLUGINS

Pass a list of plugin specs to the Mason constructor:

    Mason->new(plugins =>
            [
             'OnePlugin', 
             'AnotherPlugin',
             '+My::Mason::Plugin::AThirdPlugin',
             '@APluginBundle',
             '+My::Mason::PluginBundle::AnotherBundle',
             '-PluginIDontLike',
            ]);

Each plugin spec can be one of the following;

=over

=item *

A simple name, which will have "Mason::Plugin::" prepended to it.

=item *

A bundle name, prefixed with '@', which will have "Mason::PluginBundle::"
prepended to it.

=item *

A full plugin or bundle class name prefixed with '+'.

=item *

Any spec prefixed with '-', which means do not include these plugin(s) in the
final list.

=back

See Mason::t::Plugins::test_plugin_specs in the Mason distribution for some
examples.

=head1 DEFAULT PLUGINS

Mason will always add the L<@Default|Mason::PluginBundle::Default> bundle
regardless of whether you pass your own list. You can remove individual default
plugins that you don't like:

    plugins => ['-DollarDot', ...]

or the whole list:

    plugins => ['-@Default', ...]

=head1 CREATING PLUGINS

Note: If you want to modify behavior for a particular application only, it
might be more convenient to create L<subclasses|Mason::Manual::Subclasses>.

A plugin consists of the main plugin class and one or more roles. The main
class currently looks like this:

    package Mason::Plugin::MyPlugin;
    use Moose;
    with 'Mason::Plugin';

    # Optional: declare other plugin dependencies
    method requires_plugins { qw(A @D) }

    1;

    __END__

    =pod

    =head1 NAME

    Mason::Plugin::MyPlugin - My plugin

    ....

Its main responsibilities are to include the role 'Mason::Plugin' and document
itself. It may also specify a C<requires_plugins> that returns a list of
dependencies with the same syntax as the C<plugins> parameter to C<Mason->new>.

The real action is in the role classes, which live underneath, and each modify
a single Mason class:

    package Mason::Plugin::MyPlugin::Interp;
    use Mason::PluginRole;

    # Modify Mason::Interp

    ...

    package Mason::Plugin::MyPlugin::Compilation;
    use Mason::PluginRole;

    # Modify Mason::Compilation

    ...

When a plugin is applied, each of its roles will be automatically applied to
the appropriate Mason class. For example, in the example above
C<Mason::Plugin::MyPlugin::Interp> and C<Mason::Plugin::MyPlugin::Compilation>
will be applied to Mason::Interp and Mason::Compilation respectively.

=head2 Pluggable Mason classes

As of this writing the following Mason classes can be modified with plugins:

    Mason::CodeCache
    Mason::Compilation
    Mason::Component
    Mason::Component::ClassMeta
    Mason::Component::Import
    Mason::Component::Moose
    Mason::Interp
    Mason::Request
    Mason::Result

=head2 Extra classes in plugin

If you have extra classes in your plugin that aren't automatically providing a
role to a Mason class, put them in C<Extra.pm> or the C<Extra> subdirectory,
e.g.

   package Mason::Plugin::MyPlugin::Extra::Utils;
   ...

That will ensure that your classname will not conflict with a future Mason
class name.

=head1 CREATING PLUGIN BUNDLES

A plugin bundle just collects one or more plugins and/or other bundles. It
looks like this:

    package Mason::PluginBundle::MyBundle
    use Moose;
    with 'Mason::PluginBundle';
    
    sub requires_plugins {
        return (
            'A',
            'B',
            '+My::Plugin::C',
            '@D',
            '+My::PluginBundle::E',
            );
    }
    
    1;
    
    __END__
    
    =pod
    
    =head1 NAME
    
    Mason::PluginBundle::MyBundle - My plugin bundle
    
    =head1 INCLUDED PLUGINS
    
    =over
    
    =item A
    =item B
    =item +My::Plugin::C
    =item @D
    =item +My::PluginBundle::E
    
    =back
    
    ....

The C<requires_plugins> method returns a list of entries, with the same syntax
as the C<plugins> parameter to C<Mason->new>.

=head1 ACKNOWLEDGEMENTS

Thanks to Ricardo Signes <rjbs@cpan.org> for L<Dist::Zilla|Dist::Zilla> and
L<Pod::Weaver|Pod::Weaver>, which got me thinking in plugins and lent the
plugin and bundle name syntax.

=head1 SEE ALSO

L<Mason|Mason>

=head1 AUTHOR

Jonathan Swartz <swartz@pobox.com>

=head1 COPYRIGHT AND LICENSE

This software is copyright (c) 2012 by Jonathan Swartz.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

=cut
