1 package Moose::Meta::TypeConstraint::Parameterizable;
7 use base 'Moose::Meta::TypeConstraint';
8 use Moose::Meta::TypeConstraint::Parameterized;
9 use Moose::Util::TypeConstraints ();
11 __PACKAGE__->meta->add_attribute('constraint_generator' => (
12 accessor => 'constraint_generator',
13 predicate => 'has_constraint_generator',
16 __PACKAGE__->meta->add_attribute('inline_generator' => (
17 accessor => 'inline_generator',
18 predicate => 'has_inline_generator',
21 sub generate_constraint_for {
22 my ($self, $type) = @_;
24 return unless $self->has_constraint_generator;
26 return $self->constraint_generator->($type->type_parameter)
27 if $type->is_subtype_of($self->name);
29 return $self->_can_coerce_constraint_from($type)
30 if $self->has_coercion
31 && $self->coercion->has_coercion_for_type($type->parent->name);
36 sub _can_coerce_constraint_from {
37 my ($self, $type) = @_;
38 my $coercion = $self->coercion;
39 my $constraint = $self->constraint_generator->($type->type_parameter);
41 local $_ = $coercion->coerce($_);
46 sub _parse_type_parameter {
47 my ($self, $type_parameter) = @_;
48 return Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($type_parameter);
52 my ($self, $type_parameter) = @_;
54 my $contained_tc = $self->_parse_type_parameter($type_parameter);
56 ## The type parameter should be a subtype of the parent's type parameter
59 if(my $parent = $self->parent) {
60 if($parent->can('type_parameter')) {
61 unless ( $contained_tc->is_a_type_of($parent->type_parameter) ) {
63 Moose->throw_error("$type_parameter is not a subtype of ".$parent->type_parameter);
68 if ( $contained_tc->isa('Moose::Meta::TypeConstraint') ) {
69 my $tc_name = $self->name . '[' . $contained_tc->name . ']';
70 return Moose::Meta::TypeConstraint::Parameterized->new(
73 type_parameter => $contained_tc,
74 parameterized_from => $self,
79 Moose->throw_error("The type parameter must be a Moose meta type");
86 # ABSTRACT: 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.