Simplistic implementation of type intersections, modeled after the implementation...

[gitmo/Moose.git] / lib / Moose / Meta / TypeCoercion / Intersection.pm

diff --git a/lib/Moose/Meta/TypeCoercion/Intersection.pm b/lib/Moose/Meta/TypeCoercion/Intersection.pm
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+++ b/lib/Moose/Meta/TypeCoercion/Intersection.pm
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+
+package Moose::Meta::TypeCoercion::Intersection;
+
+use strict;
+use warnings;
+use metaclass;
+
+use Scalar::Util 'blessed';
+
+our $VERSION   = '0.70';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
+
+use base 'Moose::Meta::TypeCoercion';
+
+sub compile_type_coercion {
+    my $self            = shift;
+    my $type_constraint = $self->type_constraint;
+    
+    (blessed $type_constraint && $type_constraint->isa('Moose::Meta::TypeConstraint::Intersection'))
+     || Moose->throw_error("You can only a Moose::Meta::TypeCoercion::Intersection for a " .
+                "Moose::Meta::TypeConstraint::Intersection, not a $type_constraint");
+    
+    $self->_compiled_type_coercion(sub {
+        my $value = shift;
+        # go through all the type constraints 
+        # in the intersection, and check em ...
+        foreach my $type (@{$type_constraint->type_constraints}) {
+            # if they have a coercion first
+            if ($type->has_coercion) {    
+                # then try to coerce them ...
+                my $temp = $type->coerce($value);
+                # and if they get something 
+                # make sure it still fits within
+                # the intersection type ...
+                return $temp if $type_constraint->check($temp);
+            }
+        }
+        return undef;    
+    });
+}
+
+sub has_coercion_for_type { 0 }
+
+sub add_type_coercions {
+    Moose->throw_error("Cannot add additional type coercions to Intersection types");
+}
+
+1;
+
+__END__
+
+=pod
+
+=head1 NAME
+
+Moose::Meta::TypeCoercion::Intersection - The Moose Type Coercion metaclass for intersections
+
+=head1 DESCRIPTION
+
+For the most part, the only time you will ever encounter an 
+instance of this class is if you are doing some serious deep 
+introspection. This API should not be considered final, but 
+it is B<highly unlikely> that this will matter to a regular 
+Moose user.
+
+If you wish to use features at this depth, please come to the 
+#moose IRC channel on irc.perl.org and we can talk :)
+
+=head1 METHODS
+
+=over 4
+
+=item B<meta>
+
+=item B<compile_type_coercion>
+
+=item B<has_coercion_for_type>
+
+=item B<add_type_coercions>
+
+=back
+
+=head1 BUGS
+
+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.
+
+=head1 AUTHOR
+
+Stevan Little E<lt>stevan@iinteractive.comE<gt> and
+Adam Foxson E<lt>afoxson@pobox.comE<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2006-2009 by Infinity Interactive, Inc.
+
+L<http://www.iinteractive.com>
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself. 
+
+=cut