X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMoose%2FMeta%2FTypeCoercion.pm;h=e4e055a0e4466a385cb1a1d198cf1a3ad256e408;hb=f9b1ab71234d11a9121de96c574ca980bbfb3eaa;hp=4decb4745faeef05e6f61478febd48bdecf488e5;hpb=6bf30233976676ca157c80174a7e73f0561dca4c;p=gitmo%2FMoose.git

diff --git a/lib/Moose/Meta/TypeCoercion.pm b/lib/Moose/Meta/TypeCoercion.pm
index 4decb47..e4e055a 100644
--- a/lib/Moose/Meta/TypeCoercion.pm
+++ b/lib/Moose/Meta/TypeCoercion.pm
@@ -5,9 +5,97 @@ use strict;
 use warnings;
 use metaclass;
 
-use Carp 'confess';
+use Moose::Meta::Attribute;
+use Moose::Util::TypeConstraints ();
+
+our $VERSION   = '0.74';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
+
+__PACKAGE__->meta->add_attribute('type_coercion_map' => (
+    reader  => 'type_coercion_map',
+    default => sub { [] }
+));
+
+__PACKAGE__->meta->add_attribute(
+    Moose::Meta::Attribute->new('type_constraint' => (
+        reader   => 'type_constraint',
+        weak_ref => 1
+    ))
+);
+
+# private accessor
+__PACKAGE__->meta->add_attribute('compiled_type_coercion' => (
+    accessor => '_compiled_type_coercion'
+));
+
+sub new { 
+    my $class = shift;
+    my $self  = Class::MOP::class_of($class)->new_object(@_);
+    $self->compile_type_coercion;
+    return $self;
+}
+
+sub compile_type_coercion {
+    my $self = shift;
+    my @coercion_map = @{$self->type_coercion_map};
+    my @coercions;
+    while (@coercion_map) {
+        my ($constraint_name, $action) = splice(@coercion_map, 0, 2);
+        my $type_constraint = ref $constraint_name ? $constraint_name : Moose::Util::TypeConstraints::find_or_parse_type_constraint($constraint_name);
+
+        unless ( defined $type_constraint ) {
+            require Moose;
+            Moose->throw_error("Could not find the type constraint ($constraint_name) to coerce from");
+        }
+
+        push @coercions => [ 
+            $type_constraint->_compiled_type_constraint, 
+            $action 
+        ];
+    }
+    $self->_compiled_type_coercion(sub { 
+        my $thing = shift;
+        foreach my $coercion (@coercions) {
+            my ($constraint, $converter) = @$coercion;
+            if ($constraint->($thing)) {
+                local $_ = $thing;                
+                return $converter->($thing);
+            }
+        }
+        return $thing;
+    });    
+}
+
+sub has_coercion_for_type {
+    my ($self, $type_name) = @_;
+    my %coercion_map = @{$self->type_coercion_map};
+    exists $coercion_map{$type_name} ? 1 : 0;
+}
+
+sub add_type_coercions {
+    my ($self, @new_coercion_map) = @_;
+        
+    my $coercion_map = $self->type_coercion_map;    
+    my %has_coercion = @$coercion_map;
+    
+    while (@new_coercion_map) {
+        my ($constraint_name, $action) = splice(@new_coercion_map, 0, 2);        
+
+        if ( exists $has_coercion{$constraint_name} ) {
+            require Moose;
+            Moose->throw_error("A coercion action already exists for '$constraint_name'")
+        }
+
+        push @{$coercion_map} => ($constraint_name, $action);
+    }
+    
+    # and re-compile ...
+    $self->compile_type_coercion;
+}
+
+sub coerce { $_[0]->_compiled_type_coercion->($_[1]) }
 
-our $VERSION = '0.01';
 
 1;
 
@@ -17,17 +105,70 @@ __END__
 
 =head1 NAME
 
-Moose::Meta::TypeCoercion - The Moose Type Coercion metaobject
-
-=head1 SYNOPSIS
+Moose::Meta::TypeCoercion - The Moose Type Coercion metaclass
 
 =head1 DESCRIPTION
 
+A type coercion object is basically a mapping of one or more type
+constraints and the associated coercions subroutines.
+
+It's unlikely that you will need to instantiate an object of this
+class directly, as it's part of the deep internals of Moose.
+
 =head1 METHODS
 
 =over 4
 
-=item B<meta>
+=item B<< Moose::Meta::TypeCoercion->new(%options) >>
+
+Creates a new type coercion object, based on the options provided.
+
+=over 8
+
+=item * type_constraint
+
+This is the L<Moose::Meta::TypeConstraint> object for the type that is
+being coerced I<to>.
+
+=back
+
+=item B<< $coercion->type_coercion_map >>
+
+This returns the map of type constraints to coercions as an array
+reference. The values of the array alternate between type names and
+subroutine references which implement the coercion.
+
+The value is an array reference because coercions are tried in the
+order they are added.
+
+=item B<< $coercion->type_constraint >>
+
+This returns the L<Moose::Meta::TypeConstraint> that was passed to the
+constructor.
+
+=item B<< $coercion->has_coercion_for_type($type_name) >>
+
+Returns true if the coercion can coerce the named type.
+
+=item B<< $coercion->add_type_coercions( $type_name => $sub, ... ) >>
+
+This method takes a list of type names and subroutine references. If
+the coercion already has a mapping for a given type, it throws an
+exception.
+
+Coercions are actually
+
+=item B<< $coercion->coerce($value) >>
+
+This method takes a value and applies the first valid coercion it
+finds.
+
+This means that if the value could belong to more than type in the
+coercion object, the first coercion added is used.
+
+=item B<< Moose::Meta::TypeCoercion->meta >>
+
+This will return a L<Class::MOP::Class> instance for this class.
 
 =back
 
@@ -43,11 +184,11 @@ Stevan Little E<lt>stevan@iinteractive.comE<gt>
 
 =head1 COPYRIGHT AND LICENSE
 
-Copyright 2006 by Infinity Interactive, Inc.
+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
\ No newline at end of file
+=cut