trusty (3) MooseX::Role::Parameterized.3pm.gz

NAME

       MooseX::Role::Parameterized - roles with composition parameters

SYNOPSIS

           package Counter;
           use MooseX::Role::Parameterized;

           parameter name => (
               isa      => 'Str',
               required => 1,
           );

           role {
               my $p = shift;

               my $name = $p->name;

               has $name => (
                   is      => 'rw',
                   isa     => 'Int',
                   default => 0,
               );

               method "increment_$name" => sub {
                   my $self = shift;
                   $self->$name($self->$name + 1);
               };

               method "reset_$name" => sub {
                   my $self = shift;
                   $self->$name(0);
               };
           };

           package MyGame::Weapon;
           use Moose;

           with Counter => { name => 'enchantment' };

           package MyGame::Wand;
           use Moose;

           with Counter => { name => 'zapped' };

MooseX::Role::Parameterized::Tutorial

       Stop! If you're new here, please read MooseX::Role::Parameterized::Tutorial for a much gentler
       introduction.

DESCRIPTION

       Your parameterized role consists of two new things: parameter declarations and a "role" block.

       Parameters are declared using the "parameter" keyword which very much resembles "has" in Moose. You can
       use any option that "has" in Moose accepts. The default value for the "is" option is "ro" as that's a
       very common case. Use "is => 'bare'" if you want no accessor. These parameters will get their values when
       the consuming class (or role) uses "with" in Moose. A parameter object will be constructed with these
       values, and passed to the "role" block.

       The "role" block then uses the usual Moose::Role keywords to build up a role. You can shift off the
       parameter object to inspect what the consuming class provided as parameters. You use the parameters to
       customize your role however you wish.

       There are many possible implementations for parameterized roles (hopefully with a consistent enough API);
       I believe this to be the easiest and most flexible design. Coincidentally, Pugs originally had an eerily
       similar design.

       See MooseX::Role::Parameterized::Extending for some tips on how to extend this module.

   Why a parameters object?
       I've been asked several times "Why use a parameter object and not just a parameter hashref? That would
       eliminate the need to explicitly declare your parameters."

       The benefits of using an object are similar to the benefits of using Moose. You get an easy way to
       specify lazy defaults, type constraint, delegation, and so on. You get to use MooseX modules.

       You also get the usual introspective and intercessory abilities that come standard with the metaobject
       protocol. Ambitious users should be able to add traits to the parameters metaclass to further customize
       behavior. Please let me know if you're doing anything viciously complicated with this extension. :)

CAVEATS

       You must use this syntax to declare methods in the role block: "method NAME => sub { ... };". This is due
       to a limitation in Perl. In return though you can use parameters in your methods!

AUTHOR

       Shawn M Moore, "sartak@gmail.com"

SEE ALSO

       <http://sartak.org/2009/01/parametric-roles-in-perl-5.html>

       <http://sartak.org/2009/05/the-design-of-parameterized-roles.html>

       <http://stevan-little.blogspot.com/2009/07/thoughts-on-parameterized-roles.html>

       <http://perldition.org/articles/Parameterized%20Roles%20with%20MooseX::Declare.pod>

       <http://www.modernperlbooks.com/mt/2011/01/the-parametric-role-of-my-mvc-plugin-system.html>

       <http://jjnapiorkowski.typepad.com/modern-perl/2010/08/parameterized-roles-and-method-traits-redo.html>

       <http://sartak.org/talks/yapc-asia-2009/(parameterized)-roles/>

       <https://github.com/SamuraiJack/JooseX-Role-Parameterized> - this extension ported to JavaScript's Joose

COPYRIGHT AND LICENSE

       Copyright 2007-2010 Infinity Interactive

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