/ 
MooseX-RoleFor-0.003
River stage zero No dependents
/ MooseX::RoleFor

NAME

MooseX::RoleFor - limit the applicability of a Moose::Role

SYNOPSIS

package Watchdog;

use Moose::Role;
use MooseX::RoleFor;

role_for 'Dog';
requires 'make_noise';

sub hear_intruder
{
  my ($self) = @_;
  $self->make_noise;
}

1;

DESCRIPTION

This package allows your Moose roles to limit what classes and objects they may be composed with. This is often not a good idea - one of the advantages of roles is that they can be reused in such different contexts.

However, if you search CPAN for "TraitFor" you'll see that it's quite a common desire to indicate that a role should only be applies to certain classes.

role_for $class, $consequence

$class is a string (class name) or arrayref of strings indicating which classes this role may be composed with. Inheritance is respected.

$consequence is either "carp" (the default) or "croak".

How it works

Adding use MooseX::RoleFor to your role imports the role_for function to your class, and applies the MooseX::RoleFor::Meta::Role::Trait::RoleFor role to your role's metaclass.

The role_for function is basically:

sub role_for
{
  __PACKAGE__->meta->role_is_for($_[0])
  __PACKAGE__->meta->role_misapplication_consequence($_[1])
    if defined $_[1];
}

MooseX::RoleFor::Meta::Role::Trait::RoleFor hooks onto Moose::Meta::Role's apply method to enforce your restriction.

BUGS

Please report any bugs to http://rt.cpan.org/Dist/Display.html?Queue=MooseX-RoleFor.

Known

When misapplying a role to an instance (rather than a class), you get not one warning, but two: one for the object, and one for its metaclass.

SEE ALSO

Moose, Moose::Meta::Role.

MooseX::RoleFor::Meta::Role::Trait::RoleFor - internals.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2011-2012 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.