1 package Moose::Meta::TypeConstraint::Parameterizable;
7 use base 'Moose::Meta::TypeConstraint';
8 use Moose::Meta::TypeConstraint::Parameterized;
9 use Moose::Util::TypeConstraints ();
13 __PACKAGE__->meta->add_attribute('constraint_generator' => (
14 accessor => 'constraint_generator',
15 predicate => 'has_constraint_generator',
18 __PACKAGE__->meta->add_attribute('inline_generator' => (
19 accessor => 'inline_generator',
20 predicate => 'has_inline_generator',
23 sub generate_constraint_for {
24 my ($self, $type) = @_;
26 return unless $self->has_constraint_generator;
28 return $self->constraint_generator->($type->type_parameter)
29 if $type->is_subtype_of($self->name);
31 return $self->_can_coerce_constraint_from($type)
32 if $self->has_coercion
33 && $self->coercion->has_coercion_for_type($type->parent->name);
38 sub _can_coerce_constraint_from {
39 my ($self, $type) = @_;
40 my $coercion = $self->coercion;
41 my $constraint = $self->constraint_generator->($type->type_parameter);
43 local $_ = $coercion->coerce($_);
48 sub generate_inline_for {
49 my ($self, $type, $val) = @_;
51 confess "Can't generate an inline constraint for $type, since none "
53 unless $self->has_inline_generator;
55 return $self->inline_generator->( $self, $type, $val );
58 sub _parse_type_parameter {
59 my ($self, $type_parameter) = @_;
60 return Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($type_parameter);
64 my ($self, $type_parameter) = @_;
66 my $contained_tc = $self->_parse_type_parameter($type_parameter);
68 ## The type parameter should be a subtype of the parent's type parameter
71 if(my $parent = $self->parent) {
72 if($parent->can('type_parameter')) {
73 unless ( $contained_tc->is_a_type_of($parent->type_parameter) ) {
75 Moose->throw_error("$type_parameter is not a subtype of ".$parent->type_parameter);
80 if ( $contained_tc->isa('Moose::Meta::TypeConstraint') ) {
81 my $tc_name = $self->name . '[' . $contained_tc->name . ']';
82 return Moose::Meta::TypeConstraint::Parameterized->new(
85 type_parameter => $contained_tc,
86 parameterized_from => $self,
91 Moose->throw_error("The type parameter must be a Moose meta type");
98 # ABSTRACT: Type constraints which can take a parameter (ArrayRef)
107 This class represents a parameterizable type constraint. This is a
108 type constraint like C<ArrayRef> or C<HashRef>, that can be
109 parameterized and made more specific by specifying a contained
110 type. For example, instead of just an C<ArrayRef> of anything, you can
111 specify that is an C<ArrayRef[Int]>.
113 A parameterizable constraint should not be used as an attribute type
114 constraint. Instead, when parameterized it creates a
115 L<Moose::Meta::TypeConstraint::Parameterized> which should be used.
119 C<Moose::Meta::TypeConstraint::Parameterizable> is a subclass of
120 L<Moose::Meta::TypeConstraint>.
124 This class is intentionally not documented because the API is
125 confusing and needs some work.
129 See L<Moose/BUGS> for details on reporting bugs.