NAME¶
Mouse::Role - The Mouse Role
VERSION¶
This document describes Mouse version 2.3.0
SYNOPSIS¶
package Comparable;
use Mouse::Role; # the package is now a Mouse role
# Declare methods that are required by this role
requires qw(compare);
# Define methods this role provides
sub equals {
my($self, $other) = @_;
return $self->compare($other) == 0;
}
# and later
package MyObject;
use Mouse;
with qw(Comparable); # Now MyObject can equals()
sub compare {
# ...
}
my $foo = MyObject->new();
my $bar = MyObject->new();
$obj->equals($bar); # yes, it is comparable
DESCRIPTION¶
This module declares the caller class to be a Mouse role.
The concept of roles is documented in Moose::Manual::Roles. This document serves
as API documentation.
EXPORTED FUNCTIONS¶
Mouse::Role supports all of the functions that Mouse exports, but differs
slightly in how some items are handled (see "CAVEATS" below for
details).
Mouse::Role also offers two role-specific keywords:
"requires(@method_names)"¶
Roles can require that certain methods are implemented by any class which
"does" the role.
Note that attribute accessors also count as methods for the purposes of
satisfying the requirements of a role.
"excludes(@role_names)"¶
This is exported but not implemented in Mouse.
IMPORT AND UNIMPORT¶
import¶
Importing Mouse::Role will give you sugar. "-traits" are also
supported.
unimport¶
Please unimport ("no Mouse::Role") so that if someone calls one of the
keywords (such as "has") it will break loudly instead breaking
subtly.
CAVEATS¶
Role support has only a few caveats:
- •
- Roles cannot use the "extends" keyword; it will throw an
exception for now. The same is true of the "augment" and
"inner" keywords (not sure those really make sense for roles).
All other Mouse keywords will be deferred so that they can be
applied to the consuming class.
- •
- Role composition does its best to not be order-sensitive when it
comes to conflict resolution and requirements detection. However, it is
order-sensitive when it comes to method modifiers. All before/around/after
modifiers are included whenever a role is composed into a class, and then
applied in the order in which the roles are used. This also means that
there is no conflict for before/around/after modifiers.
In most cases, this will be a non-issue; however, it is something to keep in
mind when using method modifiers in a role. You should never assume any
ordering.
SEE ALSO¶
Mouse
Moose::Role
Moose::Manual::Roles
Moose::Spec::Role