oracular (3) Moose::Role.3pm.gz

NAME

       Moose::Role - The Moose Role

VERSION

       version 2.2207

SYNOPSIS

         package Eq;
         use Moose::Role; # automatically turns on strict and warnings

         requires 'equal';

         sub no_equal {
             my ($self, $other) = @_;
             !$self->equal($other);
         }

         # ... then in your classes

         package Currency;
         use Moose; # automatically turns on strict and warnings

         with 'Eq';

         sub equal {
             my ($self, $other) = @_;
             $self->as_float == $other->as_float;
         }

         # ... and also

         package Comparator;
         use Moose;

         has compare_to => (
             is      => 'ro',
             does    => 'Eq',
             handles => 'Eq',
         );

         # ... which allows

         my $currency1 = Currency->new(...);
         my $currency2 = Currency->new(...);
         Comparator->new(compare_to => $currency1)->equal($currency2);

DESCRIPTION

       The concept of roles is documented in Moose::Manual::Roles. This document serves as API documentation.

EXPORTED FUNCTIONS

       Moose::Role currently supports all of the functions that Moose exports, but differs slightly in how some
       items are handled (see "CAVEATS" below for details).

       Moose::Role also offers two role-specific keyword exports:

   requires (@method_names)
       Roles can require that certain methods are implemented by any class which "does" the role.

       Note that attribute accessors also count as methods for the purposes of satisfying the requirements of a
       role.

   excludes (@role_names)
       Roles can "exclude" other roles, in effect saying "I can never be combined with these @role_names". This
       is a feature which should not be used lightly.

   no Moose::Role
       Moose::Role offers a way to remove the keywords it exports, through the "unimport" method. You simply
       have to say "no Moose::Role" at the bottom of your code for this to work.

METACLASS

       When you use Moose::Role, you can specify traits which will be applied to your role metaclass:

           use Moose::Role -traits => 'My::Trait';

       This is very similar to the attribute traits feature. When you do this, your class's "meta" object will
       have the specified traits applied to it. See "Metaclass and Trait Name Resolution" in Moose for more
       details.

       All role metaclasses (note, not the role itself) extend Moose::Meta::Role.  You can test if a package is
       a role or not using "is_role" in Moose::Util.

APPLYING ROLES

       In addition to being applied to a class using the 'with' syntax (see Moose::Manual::Roles) and using the
       Moose::Util 'apply_all_roles' method, roles may also be applied to an instance of a class using
       Moose::Util 'apply_all_roles' or the role's metaclass:

          MyApp::Test::SomeRole->meta->apply( $instance );

       Doing this creates a new, mutable, anonymous subclass, applies the role to that, and reblesses. In a
       debugger, for example, you will see class names of the form " Moose::Meta::Class::__ANON__::SERIAL::6 ",
       which means that doing a 'ref' on your instance may not return what you expect. See Moose::Object for
       'DOES'.

       Additional params may be added to the new instance by providing 'rebless_params'. See
       Moose::Meta::Role::Application::ToInstance.

CAVEATS

       Role support has only a few caveats:

       •   Roles cannot use the "extends" keyword; it will throw an exception for now.  The same is true of the
           "augment" and "inner" keywords (not sure those really make sense for roles). All other Moose keywords
           will be deferred so that they can be applied to the consuming class.

       •   Role composition does its best to not be order-sensitive when it comes to conflict resolution and
           requirements detection. However, it is order-sensitive when it comes to method modifiers. All
           before/around/after modifiers are included whenever a role is composed into a class, and then applied
           in the order in which the roles are used. This also means that there is no conflict for
           before/around/after modifiers.

           In most cases, this will be a non-issue; however, it is something to keep in mind when using method
           modifiers in a role. You should never assume any ordering.

BUGS

       See "BUGS" in Moose for details on reporting bugs.

AUTHORS

       •   Stevan Little <stevan@cpan.org>

       •   Dave Rolsky <autarch@urth.org>

       •   Jesse Luehrs <doy@cpan.org>

       •   Shawn M Moore <sartak@cpan.org>

       •   יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>

       •   Karen Etheridge <ether@cpan.org>

       •   Florian Ragwitz <rafl@debian.org>

       •   Hans Dieter Pearcey <hdp@cpan.org>

       •   Chris Prather <chris@prather.org>

       •   Matt S Trout <mstrout@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2006 by Infinity Interactive, Inc.

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