1 package Moose::Meta::TypeConstraint::Parameterizable;
8 $VERSION = eval $VERSION;
9 our $AUTHORITY = 'cpan:STEVAN';
11 use base 'Moose::Meta::TypeConstraint';
12 use Moose::Meta::TypeConstraint::Parameterized;
13 use Moose::Util::TypeConstraints ();
15 __PACKAGE__->meta->add_attribute('constraint_generator' => (
16 accessor => 'constraint_generator',
17 predicate => 'has_constraint_generator',
20 sub generate_constraint_for {
21 my ($self, $type) = @_;
23 return unless $self->has_constraint_generator;
25 return $self->constraint_generator->($type->type_parameter)
26 if $type->is_subtype_of($self->name);
28 return $self->_can_coerce_constraint_from($type)
29 if $self->has_coercion
30 && $self->coercion->has_coercion_for_type($type->parent->name);
35 sub _can_coerce_constraint_from {
36 my ($self, $type) = @_;
37 my $coercion = $self->coercion;
38 my $constraint = $self->constraint_generator->($type->type_parameter);
40 local $_ = $coercion->coerce($_);
45 sub _parse_type_parameter {
46 my ($self, $type_parameter) = @_;
47 return Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($type_parameter);
51 my ($self, $type_parameter) = @_;
53 my $contained_tc = $self->_parse_type_parameter($type_parameter);
55 ## The type parameter should be a subtype of the parent's type parameter
58 if(my $parent = $self->parent) {
59 if($parent->can('type_parameter')) {
60 unless ( $contained_tc->is_a_type_of($parent->type_parameter) ) {
62 Moose->throw_error("$type_parameter is not a subtype of ".$parent->type_parameter);
67 if ( $contained_tc->isa('Moose::Meta::TypeConstraint') ) {
68 my $tc_name = $self->name . '[' . $contained_tc->name . ']';
69 return Moose::Meta::TypeConstraint::Parameterized->new(
72 type_parameter => $contained_tc,
77 Moose->throw_error("The type parameter must be a Moose meta type");
91 Moose::Meta::TypeConstraint::Parameterizable - Type constraints which can take a parameter (ArrayRef)
95 This class represents a parameterizable type constraint. This is a
96 type constraint like C<ArrayRef> or C<HashRef>, that can be
97 parameterized and made more specific by specifying a contained
98 type. For example, instead of just an C<ArrayRef> of anything, you can
99 specify that is an C<ArrayRef[Int]>.
101 A parameterizable constraint should not be used as an attribute type
102 constraint. Instead, when parameterized it creates a
103 L<Moose::Meta::TypeConstraint::Parameterized> which should be used.
107 C<Moose::Meta::TypeConstraint::Parameterizable> is a subclass of
108 L<Moose::Meta::TypeConstraint>.
112 This class is intentionally not documented because the API is
113 confusing and needs some work.
117 See L<Moose/BUGS> for details on reporting bugs.
121 Stevan Little E<lt>stevan@iinteractive.comE<gt>
123 =head1 COPYRIGHT AND LICENSE
125 Copyright 2006-2010 by Infinity Interactive, Inc.
127 L<http://www.iinteractive.com>
129 This library is free software; you can redistribute it and/or modify
130 it under the same terms as Perl itself.