1Moose::Util::MetaRole(3U)ser Contributed Perl DocumentatiMoonose::Util::MetaRole(3)
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NAME

6       Moose::Util::MetaRole - Apply roles to any metaclass, as well as the
7       object base class
8

SYNOPSIS

10         package MyApp::Moose;
11
12         use Moose ();
13         use Moose::Exporter;
14         use Moose::Util::MetaRole;
15
16         use MyApp::Role::Meta::Class;
17         use MyApp::Role::Meta::Method::Constructor;
18         use MyApp::Role::Object;
19
20         Moose::Exporter->setup_import_methods( also => 'Moose' );
21
22         sub init_meta {
23             shift;
24             my %args = @_;
25
26             Moose->init_meta(%args);
27
28             Moose::Util::MetaRole::apply_metaroles(
29                 for             => $args{for_class},
30                 class_metaroles => {
31                     class => => ['MyApp::Role::Meta::Class'],
32                     constructor => ['MyApp::Role::Meta::Method::Constructor'],
33                 },
34             );
35
36             Moose::Util::MetaRole::apply_base_class_roles(
37                 for   => $args{for_class},
38                 roles => ['MyApp::Role::Object'],
39             );
40
41             return $args{for_class}->meta();
42         }
43

DESCRIPTION

45       This utility module is designed to help authors of Moose extensions
46       write extensions that are able to cooperate with other Moose
47       extensions. To do this, you must write your extensions as roles, which
48       can then be dynamically applied to the caller's metaclasses.
49
50       This module makes sure to preserve any existing superclasses and roles
51       already set for the meta objects, which means that any number of
52       extensions can apply roles in any order.
53

USAGE

55       It is very important that you only call this module's functions when
56       your module is imported by the caller. The process of applying roles to
57       the metaclass reinitializes the metaclass object, which wipes out any
58       existing attributes already defined. However, as long as you do this
59       when your module is imported, the caller should not have any attributes
60       defined yet.
61
62       The easiest way to ensure that this happens is to use Moose::Exporter,
63       which can generate the appropriate "init_meta" method for you, and make
64       sure it is called when imported.
65

FUNCTIONS

67       This module provides two functions.
68
69   apply_metaroles( ... )
70       This function will apply roles to one or more metaclasses for the
71       specified class. It will return a new metaclass object for the class or
72       role passed in the "for" parameter.
73
74       It accepts the following parameters:
75
76       ·   for => $name
77
78           This specifies the class or for which to alter the meta classes.
79           This can be a package name, or an appropriate meta-object (a
80           Moose::Meta::Class or Moose::Meta::Role).
81
82       ·   class_metaroles => \%roles
83
84           This is a hash reference specifying which metaroles will be applied
85           to the class metaclass and its contained metaclasses and helper
86           classes.
87
88           Each key should in turn point to an array reference of role names.
89
90           It accepts the following keys:
91
92           class
93           attribute
94           method
95           wrapped_method
96           instance
97           constructor
98           destructor
99           error
100       ·   role_metaroles => \%roles
101
102           This is a hash reference specifying which metaroles will be applied
103           to the role metaclass and its contained metaclasses and helper
104           classes.
105
106           It accepts the following keys:
107
108           role
109           attribute
110           method
111           required_method
112           conflicting_method
113           application_to_class
114           application_to_role
115           application_to_instance
116           application_role_summation
117
118   apply_base_class_roles( for => $class, roles => \@roles )
119       This function will apply the specified roles to the object's base
120       class.
121

BUGS

123       See "BUGS" in Moose for details on reporting bugs.
124

AUTHOR

126       Dave Rolsky <autarch@urth.org>
127

129       Copyright 2009 by Infinity Interactive, Inc.
130
131       <http://www.iinteractive.com>
132
133       This library is free software; you can redistribute it and/or modify it
134       under the same terms as Perl itself.
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138perl v5.12.2                      2010-08-28          Moose::Util::MetaRole(3)
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