# phpman > man > Moose::Meta::Role ## NAME [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown) - The Moose Role metaclass ## VERSION version 2.2200 ## DESCRIPTION This class is a subclass of [Class::MOP::Module](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AModule/markdown) that provides additional Moose-specific functionality. Its API looks a lot like [Moose::Meta::Class](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3AClass/markdown), but internally it implements many things differently. This may change in the future. ## INHERITANCE "[Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)" is a subclass of [Class::MOP::Module](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AModule/markdown). ## METHODS ### Construction [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)->initialize($role_name) This method creates a new role object with the provided name. [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)->combine( [ $role => { ... } ], [ $role ], ... ) This method accepts a list of array references. Each array reference should contain a role name or [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown) object as its first element. The second element is an optional hash reference. The hash reference can contain "-excludes" and "-alias" keys to control how methods are composed from the role. The return value is a new [Moose::Meta::Role::Composite](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole%3A%3AComposite/markdown) that represents the combined roles. $metarole->composition_class_roles When combining multiple roles using "combine", this method is used to obtain a list of role names to be applied to the [Moose::Meta::Role::Composite](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole%3A%3AComposite/markdown) instance returned by "combine". The default implementation returns an empty list. Extensions that need to hook into role combination may wrap this method to return additional role names. [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)->create($name, %options) This method is identical to the [Moose::Meta::Class](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3AClass/markdown) "create" method. [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)->create_anon_role This method is identical to the [Moose::Meta::Class](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3AClass/markdown) "create_anon_class" method. $metarole->is_anon_role Returns true if the role is an anonymous role. $metarole->consumers Returns a list of names of classes and roles which consume this role. ### Role application $metarole->apply( $thing, @options ) This method applies a role to the given $thing. That can be another [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown), object, a [Moose::Meta::Class](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3AClass/markdown) object, or a (non-meta) object instance. The options are passed directly to the constructor for the appropriate [Moose::Meta::Role::Application](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole%3A%3AApplication/markdown) subclass. Note that this will apply the role even if the $thing in question already "does" this role. "does_role" in [Moose::Util](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AUtil/markdown) is a convenient wrapper for finding out if role application is necessary. ### Roles and other roles $metarole->get_roles This returns an array reference of roles which this role does. This list may include duplicates. $metarole->calculate_all_roles This returns a *unique* list of all roles that this role does, and all the roles that its roles do. $metarole->does_role($role) Given a role *name* or [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown) object, returns true if this role does the given role. $metarole->add_role($role) Given a [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown) object, this adds the role to the list of roles that the role does. $metarole->get_excluded_roles_list Returns a list of role names which this role excludes. $metarole->excludes_role($role_name) Given a role *name*, returns true if this role excludes the named role. $metarole->add_excluded_roles(@role_names) Given one or more role names, adds those roles to the list of excluded roles. ### Methods The methods for dealing with a role's methods are all identical in API and behavior to the same methods in [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown). $metarole->method_metaclass Returns the method metaclass name for the role. This defaults to [Moose::Meta::Role::Method](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole%3A%3AMethod/markdown). $metarole->get_method($name) $metarole->has_method($name) $metarole->add_method( $name, $body ) $metarole->get_method_list $metarole->find_method_by_name($name) These methods are all identical to the methods of the same name in [Class::MOP::Package](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3APackage/markdown) ### Attributes As with methods, the methods for dealing with a role's attribute are all identical in API and behavior to the same methods in [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown). However, attributes stored in this class are *not* stored as objects. Rather, the attribute definition is stored as a hash reference. When a role is composed into a class, this hash reference is passed directly to the metaclass's "add_attribute" method. This is quite likely to change in the future. $metarole->get_attribute($attribute_name) $metarole->has_attribute($attribute_name) $metarole->get_attribute_list $metarole->add_attribute($name, %options) $metarole->remove_attribute($attribute_name) ### Overload introspection and creation The methods for dealing with a role's overloads are all identical in API and behavior to the same methods in [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown). $metarole->is_overloaded $metarole->get_overloaded_operator($op) $metarole->has_overloaded_operator($op) $metarole->get_overload_list $metarole->get_all_overloaded_operators $metarole->add_overloaded_operator($op, $impl) $metarole->remove_overloaded_operator($op) ### Required methods $metarole->get_required_method_list Returns the list of methods required by the role. $metarole->requires_method($name) Returns true if the role requires the named method. $metarole->add_required_methods(@names) Adds the named methods to the role's list of required methods. $metarole->remove_required_methods(@names) Removes the named methods from the role's list of required methods. $metarole->add_conflicting_method(%params) Instantiate the parameters as a [Moose::Meta::Role::Method::Conflicting](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole%3A%3AMethod%3A%3AConflicting/markdown) object, then add it to the required method list. ### Method modifiers These methods act like their counterparts in [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown) and [Moose::Meta::Class](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3AClass/markdown). However, method modifiers are simply stored internally, and are not applied until the role itself is applied to a class or object. $metarole->add_after_method_modifier($method_name, $method) $metarole->add_around_method_modifier($method_name, $method) $metarole->add_before_method_modifier($method_name, $method) $metarole->add_override_method_modifier($method_name, $method) These methods all add an appropriate modifier to the internal list of modifiers. $metarole->has_after_method_modifiers $metarole->has_around_method_modifiers $metarole->has_before_method_modifiers $metarole->has_override_method_modifier Return true if the role has any modifiers of the given type. $metarole->get_after_method_modifiers($method_name) $metarole->get_around_method_modifiers($method_name) $metarole->get_before_method_modifiers($method_name) Given a method name, returns a list of the appropriate modifiers for that method. $metarole->get_override_method_modifier($method_name) Given a method name, returns the override method modifier for that method, if it has one. ### Introspection [Moose::Meta::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3AMeta%3A%3ARole/markdown)->meta This will return a [Class::MOP::Class](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMOP%3A%3AClass/markdown) instance for this class. ## BUGS See "BUGS" in Moose for details on reporting bugs. ## AUTHORS * Stevan Little <> * Dave Rolsky <> * Jesse Luehrs <> * Shawn M Moore <> * יובל קוג'מן (Yuval Kogman) <> * Karen Etheridge <> * Florian Ragwitz <> * Hans Dieter Pearcey <> * Chris Prather <> * Matt S Trout <> ## 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.