1Moose::Role(3)        User Contributed Perl Documentation       Moose::Role(3)
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3
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NAME

6       Moose::Role - The Moose Role
7

VERSION

9       version 2.2014
10

SYNOPSIS

12         package Eq;
13         use Moose::Role; # automatically turns on strict and warnings
14
15         requires 'equal';
16
17         sub no_equal {
18             my ($self, $other) = @_;
19             !$self->equal($other);
20         }
21
22         # ... then in your classes
23
24         package Currency;
25         use Moose; # automatically turns on strict and warnings
26
27         with 'Eq';
28
29         sub equal {
30             my ($self, $other) = @_;
31             $self->as_float == $other->as_float;
32         }
33
34         # ... and also
35
36         package Comparator;
37         use Moose;
38
39         has compare_to => (
40             is      => 'ro',
41             does    => 'Eq',
42             handles => 'Eq',
43         );
44
45         # ... which allows
46
47         my $currency1 = Currency->new(...);
48         my $currency2 = Currency->new(...);
49         Comparator->new(compare_to => $currency1)->equal($currency2);
50

DESCRIPTION

52       The concept of roles is documented in Moose::Manual::Roles. This
53       document serves as API documentation.
54

EXPORTED FUNCTIONS

56       Moose::Role currently supports all of the functions that Moose exports,
57       but differs slightly in how some items are handled (see "CAVEATS" below
58       for details).
59
60       Moose::Role also offers two role-specific keyword exports:
61
62   requires (@method_names)
63       Roles can require that certain methods are implemented by any class
64       which "does" the role.
65
66       Note that attribute accessors also count as methods for the purposes of
67       satisfying the requirements of a role.
68
69   excludes (@role_names)
70       Roles can "exclude" other roles, in effect saying "I can never be
71       combined with these @role_names". This is a feature which should not be
72       used lightly.
73
74   no Moose::Role
75       Moose::Role offers a way to remove the keywords it exports, through the
76       "unimport" method. You simply have to say "no Moose::Role" at the
77       bottom of your code for this to work.
78

METACLASS

80       When you use Moose::Role, you can specify traits which will be applied
81       to your role metaclass:
82
83           use Moose::Role -traits => 'My::Trait';
84
85       This is very similar to the attribute traits feature. When you do this,
86       your class's "meta" object will have the specified traits applied to
87       it. See "Metaclass and Trait Name Resolution" in Moose for more
88       details.
89
90       All role metaclasses (note, not the role itself) extend
91       Moose::Meta::Role.  You can test if a package is a role or not using
92       "is_role" in Moose::Util.
93

APPLYING ROLES

95       In addition to being applied to a class using the 'with' syntax (see
96       Moose::Manual::Roles) and using the Moose::Util 'apply_all_roles'
97       method, roles may also be applied to an instance of a class using
98       Moose::Util 'apply_all_roles' or the role's metaclass:
99
100          MyApp::Test::SomeRole->meta->apply( $instance );
101
102       Doing this creates a new, mutable, anonymous subclass, applies the role
103       to that, and reblesses. In a debugger, for example, you will see class
104       names of the form " Moose::Meta::Class::__ANON__::SERIAL::6 ", which
105       means that doing a 'ref' on your instance may not return what you
106       expect. See Moose::Object for 'DOES'.
107
108       Additional params may be added to the new instance by providing
109       'rebless_params'. See Moose::Meta::Role::Application::ToInstance.
110

CAVEATS

112       Role support has only a few caveats:
113
114       •   Roles cannot use the "extends" keyword; it will throw an exception
115           for now.  The same is true of the "augment" and "inner" keywords
116           (not sure those really make sense for roles). All other Moose
117           keywords will be deferred so that they can be applied to the
118           consuming class.
119
120       •   Role composition does its best to not be order-sensitive when it
121           comes to conflict resolution and requirements detection. However,
122           it is order-sensitive when it comes to method modifiers. All
123           before/around/after modifiers are included whenever a role is
124           composed into a class, and then applied in the order in which the
125           roles are used. This also means that there is no conflict for
126           before/around/after modifiers.
127
128           In most cases, this will be a non-issue; however, it is something
129           to keep in mind when using method modifiers in a role. You should
130           never assume any ordering.
131

BUGS

133       See "BUGS" in Moose for details on reporting bugs.
134

AUTHORS

136       •   Stevan Little <stevan@cpan.org>
137
138       •   Dave Rolsky <autarch@urth.org>
139
140       •   Jesse Luehrs <doy@cpan.org>
141
142       •   Shawn M Moore <sartak@cpan.org>
143
144       •   יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>
145
146       •   Karen Etheridge <ether@cpan.org>
147
148       •   Florian Ragwitz <rafl@debian.org>
149
150       •   Hans Dieter Pearcey <hdp@cpan.org>
151
152       •   Chris Prather <chris@prather.org>
153
154       •   Matt S Trout <mstrout@cpan.org>
155

157       This software is copyright (c) 2006 by Infinity Interactive, Inc.
158
159       This is free software; you can redistribute it and/or modify it under
160       the same terms as the Perl 5 programming language system itself.
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164perl v5.32.1                      2021-01-27                    Moose::Role(3)
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