--- name: "Role::Tiny" section: "3pm" platform: "linux" package: "perl-role-tiny" version: "2.002005-1" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/Role::Tiny" --- # Role::Tiny(3pm) Roles: a nouvelle cuisine portion size slice of Moose ## NAME Role::Tiny - Roles: a nouvelle cuisine portion size slice of Moose ## SYNOPSIS ``` package Some::Role; use Role::Tiny; sub foo { ... } sub bar { ... } around baz => sub { ... }; 1; ``` elsewhere ``` package Some::Class; use Role::Tiny::With; # bar gets imported, but not foo with 'Some::Role'; sub foo { ... } # baz is wrapped in the around modifier by Class::Method::Modifiers sub baz { ... } 1; ``` If you wanted attributes as well, look at Moo::Role. ## DESCRIPTION `"Role::Tiny"` 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, 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 will be considered methods to be composed. For example: ``` package MyRole; use List::Util qw(min); sub mysub { } use Role::Tiny; use List::Util 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 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'; with 'Some::Role1', 'Some::Role2'; ``` Composes another role into the current role (or class via Role::Tiny::With). If you have conflicts and want to resolve them in favour of Some::Role1 you can instead write: ``` with 'Some::Role1'; with 'Some::Role2'; ``` 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 for full documentation. Note that since you are not required to use method modifiers, Class::Method::Modifiers is lazily loaded and we do not declare it as a dependency. If your Role::Tiny role uses modifiers you must depend on both Class::Method::Modifiers and Role::Tiny. ### around ``` around foo => sub { ... }; ``` See "around method(s) =\> sub { ... };" in Class::Method::Modifiers for full documentation. Note that since you are not required to use method modifiers, Class::Method::Modifiers is lazily loaded and we do not declare it as a dependency. If your Role::Tiny role uses modifiers you must depend on both Class::Method::Modifiers and Role::Tiny. ### after ``` after foo => sub { ... }; ``` See "after method(s) =\> sub { ... };" in Class::Method::Modifiers for full documentation. Note that since you are not required to use method modifiers, Class::Method::Modifiers is lazily loaded and we do not declare it as a dependency. If your Role::Tiny role uses modifiers you must depend on both Class::Method::Modifiers and Role::Tiny. ### Strict and Warnings In addition to importing subroutines, using `"Role::Tiny"` applies strict and warnings to the caller. ## SUBROUTINES ### does\_role ``` if (Role::Tiny::does_role($foo, 'Some::Role')) { ... } ``` Returns true if class has been composed with role. This subroutine is also installed as -\>does on any class a Role::Tiny is composed into unless that class already has an -\>does method, so ``` if ($foo->does('Some::Role')) { ... } ``` will work for classes but to test a role, one must use ::does\_role directly. Additionally, Role::Tiny will override the standard Perl `"DOES"` method for your class. However, if `"any"` class in your class' inheritance hierarchy provides `"DOES"`, then Role::Tiny will not override it. ## METHODS ### make\_role ``` Role::Tiny->make_role('Some::Role'); ``` Makes a package into a role, but does not export any subs into it. ### apply\_roles\_to\_package ``` Role::Tiny->apply_roles_to_package( 'Some::Package', 'Some::Role', 'Some::Other::Role' ); ``` Composes role with package. See also Role::Tiny::With. ### apply\_roles\_to\_object ``` Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2)); ``` 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->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2)); ``` Creates a new class based on base, with the roles composed into it in order. New class is returned. ### is\_role ``` Role::Tiny->is_role('Some::Role1') ``` 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 is the attribute-less subset of Moo::Role; Moo::Role is a meta-protocol-less subset of the king of role systems, Moose::Role. Ovid's Role::Basic 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 "AUTHOR" and "CONTRIBUTORS" as listed above. ## LICENSE This library is free software and may be distributed under the same terms as perl itself.