use strict; use warnings; package Moose::Role; our $VERSION = '2.2207'; use Scalar::Util (); use Carp (); use Class::Load 'is_class_loaded'; use Module::Runtime 'module_notional_filename'; use Sub::Exporter; use Moose (); use Moose::Util 'throw_exception'; use Moose::Exporter; use Moose::Meta::Role; use Moose::Util::TypeConstraints; sub extends { throw_exception("RolesDoNotSupportExtends"); } sub with { Moose::Util::apply_all_roles( shift, @_ ); } sub requires { my $meta = shift; throw_exception( MustSpecifyAtleastOneMethod => role_name => $meta->name ) unless @_; $meta->add_required_methods(@_); } sub excludes { my $meta = shift; throw_exception( MustSpecifyAtleastOneRole => role_name => $meta->name ) unless @_; $meta->add_excluded_roles(@_); } sub has { my $meta = shift; my $name = shift; throw_exception( InvalidHasProvidedInARole => role_name => $meta->name, attribute_name => $name, ) if @_ == 1; my %context = Moose::Util::_caller_info; $context{context} = 'has declaration'; $context{type} = 'role'; my %options = ( definition_context => \%context, @_ ); my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ]; $meta->add_attribute( $_, %options ) for @$attrs; } sub _add_method_modifier { my $type = shift; my $meta = shift; if ( ref($_[0]) eq 'Regexp' ) { throw_exception( RolesDoNotSupportRegexReferencesForMethodModifiers => modifier_type => $type, role_name => $meta->name, ); } Moose::Util::add_method_modifier($meta, $type, \@_); } sub before { _add_method_modifier('before', @_) } sub after { _add_method_modifier('after', @_) } sub around { _add_method_modifier('around', @_) } # see Moose.pm for discussion sub super { return unless $Moose::SUPER_BODY; $Moose::SUPER_BODY->(@Moose::SUPER_ARGS); } sub override { my $meta = shift; my ( $name, $code ) = @_; $meta->add_override_method_modifier( $name, $code ); } sub inner { throw_exception("RolesDoNotSupportInner"); } sub augment { throw_exception("RolesDoNotSupportAugment"); } Moose::Exporter->setup_import_methods( with_meta => [ qw( with requires excludes has before after around override ) ], as_is => [ qw( extends super inner augment ), 'Carp::confess', 'Scalar::Util::blessed', ], ); sub init_meta { shift; my %args = @_; my $role = $args{for_class}; unless ($role) { require Moose; throw_exception( InitMetaRequiresClass => params => \%args ); } my $metaclass = $args{metaclass} || "Moose::Meta::Role"; my $meta_name = exists $args{meta_name} ? $args{meta_name} : 'meta'; throw_exception( MetaclassNotLoaded => class_name => $metaclass ) unless is_class_loaded($metaclass); throw_exception( MetaclassMustBeASubclassOfMooseMetaRole => role_name => $metaclass ) unless $metaclass->isa('Moose::Meta::Role'); # make a subtype for each Moose role role_type $role unless find_type_constraint($role); my $meta; if ( $meta = Class::MOP::get_metaclass_by_name($role) ) { unless ( $meta->isa("Moose::Meta::Role") ) { if ( $meta->isa('Moose::Meta::Class') ) { throw_exception( MetaclassIsAClassNotASubclassOfGivenMetaclass => class_name => $role, metaclass => $metaclass, ); } else { throw_exception( MetaclassIsNotASubclassOfGivenMetaclass => class_name => $role, metaclass => $metaclass, ); } } } else { $meta = $metaclass->initialize($role); my $filename = module_notional_filename($meta->name); $INC{$filename} = '(set by Moose)' unless exists $INC{$filename}; } if (defined $meta_name) { # also check for inherited non moose 'meta' method? my $existing = $meta->get_method($meta_name); if ($existing && !$existing->isa('Class::MOP::Method::Meta')) { Carp::cluck "Moose::Role is overwriting an existing method named " . "$meta_name in role $role with a method " . "which returns the class's metaclass. If this is " . "actually what you want, you should remove the " . "existing method, otherwise, you should rename or " . "disable this generated method using the " . "'-meta_name' option to 'use Moose::Role'."; } $meta->_add_meta_method($meta_name); } return $meta; } 1; # ABSTRACT: The Moose Role __END__ =pod =encoding UTF-8 =head1 NAME Moose::Role - The Moose Role =head1 VERSION version 2.2207 =head1 SYNOPSIS package Eq; use Moose::Role; # automatically turns on strict and warnings requires 'equal'; sub no_equal { my ($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); =head1 DESCRIPTION The concept of roles is documented in L. This document serves as API documentation. =head1 EXPORTED FUNCTIONS Moose::Role currently supports all of the functions that L exports, but differs slightly in how some items are handled (see L below for details). Moose::Role also offers two role-specific keyword exports: =head2 requires (@method_names) Roles can require that certain methods are implemented by any class which C the role. Note that attribute accessors also count as methods for the purposes of satisfying the requirements of a role. =head2 excludes (@role_names) Roles can C other roles, in effect saying "I can never be combined with these C<@role_names>". This is a feature which should not be used lightly. =head2 no Moose::Role Moose::Role offers a way to remove the keywords it exports, through the C method. You simply have to say C at the bottom of your code for this to work. =head1 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 C object will have the specified traits applied to it. See L for more details. All role metaclasses (note, not the role itself) extend L. You can test if a package is a role or not using L. =head1 APPLYING ROLES In addition to being applied to a class using the 'with' syntax (see L) and using the L 'apply_all_roles' method, roles may also be applied to an instance of a class using L '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 C< Moose::Meta::Class::__ANON__::SERIAL::6 >, which means that doing a 'ref' on your instance may not return what you expect. See L for 'DOES'. Additional params may be added to the new instance by providing 'rebless_params'. See L. =head1 CAVEATS Role support has only a few caveats: =over 4 =item * Roles cannot use the C keyword; it will throw an exception for now. The same is true of the C and C keywords (not sure those really make sense for roles). All other Moose keywords will be I so that they can be applied to the consuming class. =item * Role composition does its best to B 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. =back =head1 BUGS See L for details on reporting bugs. =head1 AUTHORS =over 4 =item * Stevan Little =item * Dave Rolsky =item * Jesse Luehrs =item * Shawn M Moore =item * יובל קוג'מן (Yuval Kogman) =item * Karen Etheridge =item * Florian Ragwitz =item * Hans Dieter Pearcey =item * Chris Prather =item * Matt S Trout =back =head1 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. =cut