# phpman > man > Role::Tiny ## NAME [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) - Roles: a nouvelle cuisine portion size slice of Moose ## SYNOPSIS package [Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown); use [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown); sub foo { ... } sub bar { ... } around baz => sub { ... }; 1; elsewhere package [Some::Class](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3AClass/markdown); use [Role::Tiny::With](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny%3A%3AWith/markdown); # bar gets imported, but not foo with '[Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown)'; sub foo { ... } # baz is wrapped in the around modifier by [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) sub baz { ... } 1; If you wanted attributes as well, look at [Moo::Role](https://www.chedong.com/phpMan.php/perldoc/Moo%3A%3ARole/markdown). ## DESCRIPTION "[Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)" is a minimalist role composition tool. ## ROLE COMPOSITION Role composition can be thought of as much more clever and meaningful multiple inheritance. The basics of this implementation of roles is: * If a method is already defined on a class, that method will not be composed in from the role. A method inherited by a class gets overridden by the role's method of the same name, though. * If a method that the role "requires" to be implemented is not implemented, role application will fail loudly. Unlike [Class::C3](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AC3/markdown), where the last class inherited from "wins," role composition is the other way around, where the class wins. If multiple roles are applied in a single call (single with statement), then if any of their provided methods clash, an exception is raised unless the class provides a method since this conflict indicates a potential problem. ROLE METHODS All subs created after importing [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) will be considered methods to be composed. For example: package MyRole; use [List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown) qw(min); sub mysub { } use [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown); use [List::Util](https://www.chedong.com/phpMan.php/perldoc/List%3A%3AUtil/markdown) qw(max); sub mymethod { } In this role, "max" and "mymethod" will be included when composing MyRole, and "min" and "mysub" will not. For additional control, [namespace::clean](https://www.chedong.com/phpMan.php/perldoc/namespace%3A%3Aclean/markdown) can be used to exclude undesired subs from roles. ## IMPORTED SUBROUTINES requires requires qw(foo bar); Declares a list of methods that must be defined to compose role. with with '[Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown)'; with '[Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown)', '[Some::Role2](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole2/markdown)'; Composes another role into the current role (or class via [Role::Tiny::With](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny%3A%3AWith/markdown)). If you have conflicts and want to resolve them in favour of [Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown) you can instead write: with '[Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown)'; with '[Some::Role2](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole2/markdown)'; If you have conflicts and want to resolve different conflicts in favour of different roles, please refactor your codebase. before before foo => sub { ... }; See "before method(s) => sub { ... };" in [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) for full documentation. Note that since you are not required to use method modifiers, [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) is lazily loaded and we do not declare it as a dependency. If your [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) role uses modifiers you must depend on both [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) and [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown). around around foo => sub { ... }; See "around method(s) => sub { ... };" in [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) for full documentation. Note that since you are not required to use method modifiers, [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) is lazily loaded and we do not declare it as a dependency. If your [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) role uses modifiers you must depend on both [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) and [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown). after after foo => sub { ... }; See "after method(s) => sub { ... };" in [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) for full documentation. Note that since you are not required to use method modifiers, [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) is lazily loaded and we do not declare it as a dependency. If your [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) role uses modifiers you must depend on both [Class::Method::Modifiers](https://www.chedong.com/phpMan.php/perldoc/Class%3A%3AMethod%3A%3AModifiers/markdown) and [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown). ### Strict and Warnings In addition to importing subroutines, using "[Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)" applies strict and warnings to the caller. ## SUBROUTINES does_role if ([Role::Tiny::does_role](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny%3A%3Adoesrole/markdown)($foo, '[Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown)')) { ... } Returns true if class has been composed with role. This subroutine is also installed as ->does on any class a [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) is composed into unless that class already has an ->does method, so if ($foo->does('[Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown)')) { ... } will work for classes but to test a role, one must use ::does_role directly. Additionally, [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) will override the standard Perl "DOES" method for your class. However, if "any" class in your class' inheritance hierarchy provides "DOES", then [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) will not override it. ## METHODS make_role [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)->make_role('[Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown)'); Makes a package into a role, but does not export any subs into it. apply_roles_to_package [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)->apply_roles_to_package( '[Some::Package](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3APackage/markdown)', '[Some::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole/markdown)', '[Some::Other::Role](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3AOther%3A%3ARole/markdown)' ); Composes role with package. See also [Role::Tiny::With](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny%3A%3AWith/markdown). apply_roles_to_object [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)->apply_roles_to_object($foo, qw([Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown) [Some::Role2](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole2/markdown))); Composes roles in order into object directly. Object is reblessed into the resulting class. Note that the object's methods get overridden by the role's ones with the same names. create_class_with_roles [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)->create_class_with_roles('[Some::Base](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ABase/markdown)', qw([Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown) [Some::Role2](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole2/markdown))); Creates a new class based on base, with the roles composed into it in order. New class is returned. is_role [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown)->is_role('[Some::Role1](https://www.chedong.com/phpMan.php/perldoc/Some%3A%3ARole1/markdown)') Returns true if the given package is a role. ## CAVEATS * On perl 5.8.8 and earlier, applying a role to an object won't apply any overloads from the role to other copies of the object. * On perl 5.16 and earlier, applying a role to a class won't apply any overloads from the role to any existing instances of the class. ## SEE ALSO [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) is the attribute-less subset of [Moo::Role](https://www.chedong.com/phpMan.php/perldoc/Moo%3A%3ARole/markdown); [Moo::Role](https://www.chedong.com/phpMan.php/perldoc/Moo%3A%3ARole/markdown) is a meta-protocol-less subset of the king of role systems, [Moose::Role](https://www.chedong.com/phpMan.php/perldoc/Moose%3A%3ARole/markdown). Ovid's [Role::Basic](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ABasic/markdown) provides roles with a similar scope, but without method modifiers, and having some extra usage restrictions. ## AUTHOR mst - Matt S. Trout (cpan:MSTROUT) <> ## CONTRIBUTORS dg - David Leadbeater (cpan:DGL) <> frew - Arthur Axel "fREW" Schmidt (cpan:FREW) <> hobbs - Andrew Rodland (cpan:ARODLAND) <> jnap - John Napiorkowski (cpan:JJNAPIORK) <> ribasushi - Peter Rabbitson (cpan:RIBASUSHI) <> chip - Chip Salzenberg (cpan:CHIPS) <> ajgb - Alex J. G. Burzyński (cpan:AJGB) <> doy - Jesse Luehrs (cpan:DOY) perigrin - Chris Prather (cpan:PERIGRIN) <> Mithaldu - Christian Walde (cpan:MITHALDU) <> ilmari - Dagfinn Ilmari Mannsåker (cpan:ILMARI) <> tobyink - Toby Inkster (cpan:TOBYINK) <> haarg - Graham Knop (cpan:HAARG) <> ## COPYRIGHT Copyright (c) 2010-2012 the [Role::Tiny](https://www.chedong.com/phpMan.php/perldoc/Role%3A%3ATiny/markdown) "AUTHOR" and "CONTRIBUTORS" as listed above. ## LICENSE This library is free software and may be distributed under the same terms as perl itself.