-
package Moose::Role;
-
use strict;
use warnings;
-use Scalar::Util ();
-use Carp 'confess';
-use Sub::Name 'subname';
+use Scalar::Util 'blessed';
+use Carp 'croak';
+use Class::Load 'is_class_loaded';
+
+use Sub::Exporter;
-our $VERSION = '0.02';
+use Moose ();
+use Moose::Util ();
+use Moose::Exporter;
use Moose::Meta::Role;
+use Moose::Util::TypeConstraints;
+
+sub extends {
+ croak "Roles do not support 'extends' (you can use 'with' to specialize a role)";
+}
+
+sub with {
+ Moose::Util::apply_all_roles( shift, @_ );
+}
+
+sub requires {
+ my $meta = shift;
+ croak "Must specify at least one method" unless @_;
+ $meta->add_required_methods(@_);
+}
+
+sub excludes {
+ my $meta = shift;
+ croak "Must specify at least one role" unless @_;
+ $meta->add_excluded_roles(@_);
+}
+
+sub has {
+ my $meta = shift;
+ my $name = shift;
+ croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1;
+ my %options = ( definition_context => Moose::Util::_caller_info(), @_ );
+ my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
+ $meta->add_attribute( $_, %options ) for @$attrs;
+}
+
+sub _add_method_modifier {
+ my $type = shift;
+ my $meta = shift;
+
+ if ( ref($_[0]) eq 'Regexp' ) {
+ croak "Roles do not currently support regex "
+ . " references for $type method modifiers";
+ }
+
+ Moose::Util::add_method_modifier($meta, $type, \@_);
+}
-sub import {
- shift;
- my $pkg = caller();
-
- # we should never export to main
- return if $pkg eq 'main';
-
- Moose::Util::TypeConstraints->import($pkg);
-
- my $meta;
- if ($pkg->can('meta')) {
- $meta = $pkg->meta();
- (blessed($meta) && $meta->isa('Moose::Meta::Role'))
- || confess "Whoops, not møøsey enough";
- }
- else {
- $meta = Moose::Meta::Role->new(role_name => $pkg);
- $meta->_role_meta->add_method('meta' => sub { $meta })
- }
-
- # NOTE:
- # &alias_method will install the method, but it
- # will not name it with
-
- # handle superclasses
- $meta->alias_method('extends' => subname 'Moose::Role::extends' => sub {
- confess "Moose::Role does not currently support 'extends'"
- });
-
- # handle roles
- $meta->alias_method('with' => subname 'Moose::with' => sub {
- my ($role) = @_;
- Moose::_load_all_classes($role);
- $role->meta->apply($meta);
- });
-
- # required methods
- $meta->alias_method('requires' => subname 'Moose::requires' => sub {
- $meta->add_required_methods(@_);
- });
-
- # handle attributes
- $meta->alias_method('has' => subname 'Moose::Role::has' => sub {
- my ($name, %options) = @_;
- $meta->add_attribute($name, %options)
- });
-
- # handle method modifers
- $meta->alias_method('before' => subname 'Moose::Role::before' => sub {
- my $code = pop @_;
- $meta->add_before_method_modifier($_, $code) for @_;
- });
- $meta->alias_method('after' => subname 'Moose::Role::after' => sub {
- my $code = pop @_;
- $meta->add_after_method_modifier($_, $code) for @_;
- });
- $meta->alias_method('around' => subname 'Moose::Role::around' => sub {
- my $code = pop @_;
- $meta->add_around_method_modifier($_, $code) for @_;
- });
-
- $meta->alias_method('super' => subname 'Moose::Role::super' => sub {});
- $meta->alias_method('override' => subname 'Moose::Role::override' => sub {
- my ($name, $code) = @_;
- $meta->add_override_method_modifier($name, $code);
- });
-
- $meta->alias_method('inner' => subname 'Moose::Role::inner' => sub {
- confess "Moose::Role does not currently support 'inner'";
- });
- $meta->alias_method('augment' => subname 'Moose::Role::augment' => sub {
- confess "Moose::Role does not currently support 'augment'";
- });
-
- # we recommend using these things
- # so export them for them
- $meta->alias_method('confess' => \&Carp::confess);
- $meta->alias_method('blessed' => \&Scalar::Util::blessed);
+sub before { _add_method_modifier('before', @_) }
+
+sub after { _add_method_modifier('after', @_) }
+
+sub around { _add_method_modifier('around', @_) }
+
+# see Moose.pm for discussion
+sub super {
+ return unless $Moose::SUPER_BODY;
+ $Moose::SUPER_BODY->(@Moose::SUPER_ARGS);
+}
+
+sub override {
+ my $meta = shift;
+ my ( $name, $code ) = @_;
+ $meta->add_override_method_modifier( $name, $code );
+}
+
+sub inner {
+ croak "Roles cannot support 'inner'";
+}
+
+sub augment {
+ croak "Roles cannot support 'augment'";
+}
+
+Moose::Exporter->setup_import_methods(
+ with_meta => [
+ qw( with requires excludes has before after around override )
+ ],
+ as_is => [
+ qw( extends super inner augment ),
+ \&Carp::confess,
+ \&Scalar::Util::blessed,
+ ],
+);
+
+sub init_meta {
+ shift;
+ my %args = @_;
+
+ my $role = $args{for_class};
+
+ unless ($role) {
+ require Moose;
+ Moose->throw_error("Cannot call init_meta without specifying a for_class");
+ }
+
+ my $metaclass = $args{metaclass} || "Moose::Meta::Role";
+ my $meta_name = exists $args{meta_name} ? $args{meta_name} : 'meta';
+
+ Moose->throw_error("The Metaclass $metaclass must be loaded. (Perhaps you forgot to 'use $metaclass'?)")
+ unless is_class_loaded($metaclass);
+
+ Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Role.")
+ unless $metaclass->isa('Moose::Meta::Role');
+
+ # make a subtype for each Moose role
+ role_type $role unless find_type_constraint($role);
+
+ my $meta;
+ if ( $meta = Class::MOP::get_metaclass_by_name($role) ) {
+ unless ( $meta->isa("Moose::Meta::Role") ) {
+ my $error_message = "$role already has a metaclass, but it does not inherit $metaclass ($meta).";
+ if ( $meta->isa('Moose::Meta::Class') ) {
+ Moose->throw_error($error_message . ' You cannot make the same thing a role and a class. Remove either Moose or Moose::Role.');
+ } else {
+ Moose->throw_error($error_message);
+ }
+ }
+ }
+ else {
+ $meta = $metaclass->initialize($role);
+ }
+
+ if (defined $meta_name) {
+ # also check for inherited non moose 'meta' method?
+ my $existing = $meta->get_method($meta_name);
+ if ($existing && !$existing->isa('Class::MOP::Method::Meta')) {
+ Carp::cluck "Moose::Role is overwriting an existing method named "
+ . "$meta_name in role $role with a method "
+ . "which returns the class's metaclass. If this is "
+ . "actually what you want, you should remove the "
+ . "existing method, otherwise, you should rename or "
+ . "disable this generated method using the "
+ . "'-meta_name' option to 'use Moose::Role'.";
+ }
+ $meta->_add_meta_method($meta_name);
+ }
+
+ return $meta;
}
1;
+# ABSTRACT: The Moose Role
+
__END__
=pod
-=head1 NAME
-
-Moose::Role - The Moose Role
-
=head1 SYNOPSIS
package Eq;
- use strict;
- use warnings;
- use Moose::Role;
-
- sub equal { confess "equal must be implemented" }
-
- sub no_equal {
+ use Moose::Role; # automatically turns on strict and warnings
+
+ requires 'equal';
+
+ sub no_equal {
my ($self, $other) = @_;
!$self->equal($other);
}
-
+
# ... then in your classes
-
+
package Currency;
- use strict;
- use warnings;
- use Moose;
-
+ use Moose; # automatically turns on strict and warnings
+
with 'Eq';
-
+
sub equal {
my ($self, $other) = @_;
$self->as_float == $other->as_float;
}
-=head1 DESCRIPTION
+ # ... and also
-This is currently a very early release of Perl 6 style Roles for
-Moose, it should be considered experimental and incomplete.
+ package Comparator;
+ use Moose;
-This feature is being actively developed, but $work is currently
-preventing me from paying as much attention to it as I would like.
-So I am releasing it in hopes people will help me on this I<hint hint>.
+ has compare_to => (
+ is => 'ro',
+ does => 'Eq',
+ handles => 'Eq',
+ );
-If you are interested in helping, please come to #moose on irc.perl.org
-and we can talk.
+ # ... which allows
-=head1 CAVEATS
+ my $currency1 = Currency->new(...);
+ my $currency2 = Currency->new(...);
+ Comparator->new(compare_to => $currency1)->equal($currency2);
-Currently, the role support has a number of caveats. They are as follows:
+=head1 DESCRIPTION
-=over 4
+The concept of roles is documented in L<Moose::Manual::Roles>. This document
+serves as API documentation.
-=item *
+=head1 EXPORTED FUNCTIONS
-There is no support for Roles consuming other Roles. The details of this
-are not totally worked out yet, but it will mostly follow what is set out
-in the Perl 6 Synopsis 12.
+Moose::Role currently supports all of the functions that L<Moose> exports, but
+differs slightly in how some items are handled (see L</CAVEATS> below for
+details).
-=item *
+Moose::Role also offers two role-specific keyword exports:
-At this time classes I<can> consume more than one Role, but they are simply
-applied one after another in the order you ask for them. This is incorrect
-behavior, the roles should be merged first, and conflicts determined, etc.
-However, if your roles do not have any conflicts, then things will work just
-fine.
+=over 4
-=item *
+=item B<requires (@method_names)>
-I want to have B<required> methods, which is unlike Perl 6 roles, and more
-like the original Traits on which roles are based. This would be similar
-in behavior to L<Class::Trait>. These are not yet implemented or course.
+Roles can require that certain methods are implemented by any class which
+C<does> the role.
-=item *
+Note that attribute accessors also count as methods for the purposes
+of satisfying the requirements of a role.
-Roles cannot use the C<extends> keyword, it will throw an exception for now.
-The same is true of the C<augment> and C<inner> keywords (not sure those
-really make sense for roles). All other Moose keywords will be I<deferred>
-so that they can be applied to the consuming class.
+=item B<excludes (@role_names)>
+
+Roles can C<exclude> other roles, in effect saying "I can never be combined
+with these C<@role_names>". This is a feature which should not be used
+lightly.
=back
-Basically thats all I can think of for now, I am sure there are more though.
+=head2 B<unimport>
-=head1 BUGS
+Moose::Role offers a way to remove the keywords it exports, through the
+C<unimport> method. You simply have to say C<no Moose::Role> at the bottom of
+your code for this to work.
+
+=head1 METACLASS
+
+When you use Moose::Role, you can specify traits which will be applied to your
+role metaclass:
-All complex software has bugs lurking in it, and this module is no
-exception. If you find a bug please either email me, or add the bug
-to cpan-RT.
+ use Moose::Role -traits => 'My::Trait';
-=head1 AUTHOR
+This is very similar to the attribute traits feature. When you do
+this, your class's C<meta> object will have the specified traits
+applied to it. See L<Moose/Metaclass and Trait Name Resolution> for more
+details.
-Stevan Little E<lt>stevan@iinteractive.comE<gt>
+=head1 APPLYING ROLES
-=head1 COPYRIGHT AND LICENSE
+In addition to being applied to a class using the 'with' syntax (see
+L<Moose::Manual::Roles>) and using the L<Moose::Util> 'apply_all_roles'
+method, roles may also be applied to an instance of a class using
+L<Moose::Util> 'apply_all_roles' or the role's metaclass:
-Copyright 2006 by Infinity Interactive, Inc.
+ MyApp::Test::SomeRole->meta->apply( $instance );
-L<http://www.iinteractive.com>
+Doing this creates a new, mutable, anonymous subclass, applies the role to that,
+and reblesses. In a debugger, for example, you will see class names of the
+form C< Moose::Meta::Class::__ANON__::SERIAL::6 >, which means that doing a
+'ref' on your instance may not return what you expect. See L<Moose::Object> for
+'DOES'.
+
+Additional params may be added to the new instance by providing
+'rebless_params'. See L<Moose::Meta::Role::Application::ToInstance>.
+
+=head1 CAVEATS
+
+Role support has only a few caveats:
+
+=over 4
+
+=item *
+
+Roles cannot use the C<extends> keyword; it will throw an exception for now.
+The same is true of the C<augment> and C<inner> keywords (not sure those
+really make sense for roles). All other Moose keywords will be I<deferred>
+so that they can be applied to the consuming class.
+
+=item *
+
+Role composition does its best to B<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.
+
+=back
+
+=head1 BUGS
-This library is free software; you can redistribute it and/or modify
-it under the same terms as Perl itself.
+See L<Moose/BUGS> for details on reporting bugs.
-=cut
\ No newline at end of file
+=cut
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