support requires on Mouse::Role.

[gitmo/Mouse.git] / lib / Mouse / Meta / Role.pm

diff --git a/lib/Mouse/Meta/Role.pm b/lib/Mouse/Meta/Role.pm
index 07203c3..ebb929f 100644 (file)
--- a/lib/Mouse/Meta/Role.pm
+++ b/lib/Mouse/Meta/Role.pm
@@ -2,6 +2,7 @@
 package Mouse::Meta::Role;
 use strict;
 use warnings;
+use Carp 'confess';
 
 do {
     my %METACLASS_CACHE;
@@ -27,13 +28,20 @@ sub new {
     my $class = shift;
     my %args  = @_;
 
-    $args{attributes} ||= {};
+    $args{attributes}       ||= {};
+    $args{required_methods} ||= [];
 
     bless \%args, $class;
 }
 
 sub name { $_[0]->{name} }
 
+sub add_required_methods {
+    my $self = shift;
+    my @methods = @_;
+    push @{$self->{required_methods}}, @methods;
+}
+
 sub add_attribute {
     my $self = shift;
     my $name = shift;
@@ -49,6 +57,12 @@ sub apply {
     my $self  = shift;
     my $class = shift;
 
+    for my $name (@{$self->{required_methods}}) {
+        unless ($class->name->can($name)) {
+            confess "'@{[ $self->name ]}' requires the method '$name' to be implemented by '@{[ $class->name ]}'";
+        }
+    }
+
     for my $name ($self->get_attribute_list) {
         next if $class->has_attribute($name);
         my $spec = $self->get_attribute($name);