2 package Moose::Util::TypeConstraints;
5 use List::MoreUtils qw( all any );
6 use Scalar::Util qw( blessed reftype );
10 $VERSION = eval $VERSION;
11 our $AUTHORITY = 'cpan:STEVAN';
13 ## --------------------------------------------------------
14 # Prototyped subs must be predeclared because we have a
15 # circular dependency with Moose::Meta::Attribute et. al.
16 # so in case of us being use'd first the predeclaration
17 # ensures the prototypes are in scope when consumers are
26 ## --------------------------------------------------------
28 use Moose::Deprecated;
29 use Moose::Meta::TypeConstraint;
30 use Moose::Meta::TypeConstraint::Union;
31 use Moose::Meta::TypeConstraint::Parameterized;
32 use Moose::Meta::TypeConstraint::Parameterizable;
33 use Moose::Meta::TypeConstraint::Class;
34 use Moose::Meta::TypeConstraint::Role;
35 use Moose::Meta::TypeConstraint::Enum;
36 use Moose::Meta::TypeConstraint::DuckType;
37 use Moose::Meta::TypeCoercion;
38 use Moose::Meta::TypeCoercion::Union;
39 use Moose::Meta::TypeConstraint::Registry;
40 use Moose::Util::TypeConstraints::OptimizedConstraints;
42 Moose::Exporter->setup_import_methods(
45 type subtype class_type role_type maybe_type duck_type
46 as where message optimize_as
50 register_type_constraint
55 ## --------------------------------------------------------
56 ## type registry and some useful functions for it
57 ## --------------------------------------------------------
59 my $REGISTRY = Moose::Meta::TypeConstraint::Registry->new;
61 sub get_type_constraint_registry {$REGISTRY}
62 sub list_all_type_constraints { keys %{ $REGISTRY->type_constraints } }
64 sub export_type_constraints_as_functions {
67 foreach my $constraint ( keys %{ $REGISTRY->type_constraints } ) {
68 my $tc = $REGISTRY->get_type_constraint($constraint)
69 ->_compiled_type_constraint;
70 *{"${pkg}::${constraint}"}
71 = sub { $tc->( $_[0] ) ? 1 : undef }; # the undef is for compat
75 sub create_type_constraint_union {
76 my @type_constraint_names;
78 if ( scalar @_ == 1 && _detect_type_constraint_union( $_[0] ) ) {
79 @type_constraint_names = _parse_type_constraint_union( $_[0] );
82 @type_constraint_names = @_;
85 ( scalar @type_constraint_names >= 2 )
86 || __PACKAGE__->_throw_error(
87 "You must pass in at least 2 type names to make a union");
89 my @type_constraints = map {
90 find_or_parse_type_constraint($_)
91 || __PACKAGE__->_throw_error(
92 "Could not locate type constraint ($_) for the union");
93 } @type_constraint_names;
95 return Moose::Meta::TypeConstraint::Union->new(
96 type_constraints => \@type_constraints );
99 sub create_parameterized_type_constraint {
100 my $type_constraint_name = shift;
101 my ( $base_type, $type_parameter )
102 = _parse_parameterized_type_constraint($type_constraint_name);
104 ( defined $base_type && defined $type_parameter )
105 || __PACKAGE__->_throw_error(
106 "Could not parse type name ($type_constraint_name) correctly");
108 if ( $REGISTRY->has_type_constraint($base_type) ) {
109 my $base_type_tc = $REGISTRY->get_type_constraint($base_type);
110 return _create_parameterized_type_constraint(
116 __PACKAGE__->_throw_error(
117 "Could not locate the base type ($base_type)");
121 sub _create_parameterized_type_constraint {
122 my ( $base_type_tc, $type_parameter ) = @_;
123 if ( $base_type_tc->can('parameterize') ) {
124 return $base_type_tc->parameterize($type_parameter);
127 return Moose::Meta::TypeConstraint::Parameterized->new(
128 name => $base_type_tc->name . '[' . $type_parameter . ']',
129 parent => $base_type_tc,
131 find_or_create_isa_type_constraint($type_parameter),
136 #should we also support optimized checks?
137 sub create_class_type_constraint {
138 my ( $class, $options ) = @_;
140 # too early for this check
141 #find_type_constraint("ClassName")->check($class)
142 # || __PACKAGE__->_throw_error("Can't create a class type constraint because '$class' is not a class name");
150 $options{name} ||= "__ANON__";
152 Moose::Meta::TypeConstraint::Class->new(%options);
155 sub create_role_type_constraint {
156 my ( $role, $options ) = @_;
158 # too early for this check
159 #find_type_constraint("ClassName")->check($class)
160 # || __PACKAGE__->_throw_error("Can't create a class type constraint because '$class' is not a class name");
168 $options{name} ||= "__ANON__";
170 Moose::Meta::TypeConstraint::Role->new(%options);
173 sub find_or_create_type_constraint {
174 my ( $type_constraint_name, $options_for_anon_type ) = @_;
177 = find_or_parse_type_constraint($type_constraint_name) ) {
180 elsif ( defined $options_for_anon_type ) {
183 # if there is no $options_for_anon_type
184 # specified, then we assume they don't
185 # want to create one, and return nothing.
187 # otherwise assume that we should create
188 # an ANON type with the $options_for_anon_type
189 # options which can be passed in. It should
190 # be noted that these don't get registered
191 # so we need to return it.
193 return Moose::Meta::TypeConstraint->new(
195 %{$options_for_anon_type}
202 sub find_or_create_isa_type_constraint {
203 my $type_constraint_name = shift;
204 find_or_parse_type_constraint($type_constraint_name)
205 || create_class_type_constraint($type_constraint_name);
208 sub find_or_create_does_type_constraint {
209 my $type_constraint_name = shift;
210 find_or_parse_type_constraint($type_constraint_name)
211 || create_role_type_constraint($type_constraint_name);
214 sub find_or_parse_type_constraint {
215 my $type_constraint_name = normalize_type_constraint_name(shift);
218 if ( $constraint = find_type_constraint($type_constraint_name) ) {
221 elsif ( _detect_type_constraint_union($type_constraint_name) ) {
222 $constraint = create_type_constraint_union($type_constraint_name);
224 elsif ( _detect_parameterized_type_constraint($type_constraint_name) ) {
226 = create_parameterized_type_constraint($type_constraint_name);
232 $REGISTRY->add_type_constraint($constraint);
236 sub normalize_type_constraint_name {
237 my $type_constraint_name = shift;
238 $type_constraint_name =~ s/\s//g;
239 return $type_constraint_name;
245 local $Carp::CarpLevel = $Carp::CarpLevel + 1;
246 Carp::confess($error);
249 ## --------------------------------------------------------
250 ## exported functions ...
251 ## --------------------------------------------------------
253 sub find_type_constraint {
256 if ( blessed $type and $type->isa("Moose::Meta::TypeConstraint") ) {
260 return unless $REGISTRY->has_type_constraint($type);
261 return $REGISTRY->get_type_constraint($type);
265 sub register_type_constraint {
266 my $constraint = shift;
267 __PACKAGE__->_throw_error("can't register an unnamed type constraint")
268 unless defined $constraint->name;
269 $REGISTRY->add_type_constraint($constraint);
277 # back-compat version, called without sugar
278 if ( !any { ( reftype($_) || '' ) eq 'HASH' } @_ ) {
279 Moose::Deprecated::deprecated(
280 feature => 'type without sugar',
282 'Calling type() with a simple list of parameters is deprecated'
285 return _create_type_constraint( $_[0], undef, $_[1] );
290 my %p = map { %{$_} } @_;
292 return _create_type_constraint(
293 $name, undef, $p{where}, $p{message},
300 # crazy back-compat code for being called without sugar ...
302 # subtype 'Parent', sub { where };
303 if ( scalar @_ == 2 && ( reftype( $_[1] ) || '' ) eq 'CODE' ) {
304 Moose::Deprecated::deprecated(
305 feature => 'subtype without sugar',
307 'Calling subtype() with a simple list of parameters is deprecated'
310 return _create_type_constraint( undef, @_ );
313 # subtype 'Parent', sub { where }, sub { message };
314 # subtype 'Parent', sub { where }, sub { message }, sub { optimized };
315 if ( scalar @_ >= 3 && all { ( reftype($_) || '' ) eq 'CODE' }
317 Moose::Deprecated::deprecated(
318 feature => 'subtype without sugar',
320 'Calling subtype() with a simple list of parameters is deprecated'
323 return _create_type_constraint( undef, @_ );
326 # subtype 'Name', 'Parent', ...
327 if ( scalar @_ >= 2 && all { !ref } @_[ 0, 1 ] ) {
328 Moose::Deprecated::deprecated(
329 feature => 'subtype without sugar',
331 'Calling subtype() with a simple list of parameters is deprecated'
334 return _create_type_constraint(@_);
337 if ( @_ == 1 && !ref $_[0] ) {
338 __PACKAGE__->_throw_error(
339 'A subtype cannot consist solely of a name, it must have a parent'
343 # The blessed check is mostly to accommodate MooseX::Types, which
344 # uses an object which overloads stringification as a type name.
345 my $name = ref $_[0] && !blessed $_[0] ? undef : shift;
347 my %p = map { %{$_} } @_;
349 # subtype Str => where { ... };
350 if ( !exists $p{as} ) {
355 return _create_type_constraint(
356 $name, $p{as}, $p{where}, $p{message},
362 register_type_constraint(
363 create_class_type_constraint(
365 ( defined( $_[1] ) ? $_[1] : () ),
370 sub role_type ($;$) {
371 register_type_constraint(
372 create_role_type_constraint(
374 ( defined( $_[1] ) ? $_[1] : () ),
380 my ($type_parameter) = @_;
382 register_type_constraint(
383 $REGISTRY->get_type_constraint('Maybe')->parameterize($type_parameter)
388 my ( $type_name, @methods ) = @_;
389 if ( ref $type_name eq 'ARRAY' && !@methods ) {
390 @methods = @$type_name;
393 if ( @methods == 1 && ref $methods[0] eq 'ARRAY' ) {
394 @methods = @{ $methods[0] };
397 register_type_constraint(
398 create_duck_type_constraint(
406 my ( $type_name, @coercion_map ) = @_;
407 _install_type_coercions( $type_name, \@coercion_map );
410 # The trick of returning @_ lets us avoid having to specify a
411 # prototype. Perl will parse this:
419 # subtype( 'Foo', as( 'Str', where { ... } ) );
421 # If as() returns all it's extra arguments, this just works, and
422 # preserves backwards compatibility.
423 sub as { { as => shift }, @_ }
424 sub where (&) { { where => $_[0] } }
425 sub message (&) { { message => $_[0] } }
426 sub optimize_as (&) { { optimize_as => $_[0] } }
429 sub via (&) { $_[0] }
432 my ( $type_name, @values ) = @_;
435 # if only an array-ref is passed then
436 # you get an anon-enum
438 if ( ref $type_name eq 'ARRAY' ) {
440 || __PACKAGE__->_throw_error("enum called with an array reference and additional arguments. Did you mean to parenthesize the enum call's parameters?");
442 @values = @$type_name;
445 if ( @values == 1 && ref $values[0] eq 'ARRAY' ) {
446 @values = @{ $values[0] };
449 register_type_constraint(
450 create_enum_type_constraint(
457 sub create_enum_type_constraint {
458 my ( $type_name, $values ) = @_;
460 Moose::Meta::TypeConstraint::Enum->new(
461 name => $type_name || '__ANON__',
466 sub create_duck_type_constraint {
467 my ( $type_name, $methods ) = @_;
469 Moose::Meta::TypeConstraint::DuckType->new(
470 name => $type_name || '__ANON__',
476 my ($to_match, @cases) = @_;
478 if (@cases % 2 != 0) {
479 $default = pop @cases;
480 (ref $default eq 'CODE')
481 || __PACKAGE__->_throw_error("Default case must be a CODE ref, not $default");
484 my ($type, $action) = splice @cases, 0, 2;
486 unless (blessed $type && $type->isa('Moose::Meta::TypeConstraint')) {
487 $type = find_or_parse_type_constraint($type)
488 || __PACKAGE__->_throw_error("Cannot find or parse the type '$type'")
491 (ref $action eq 'CODE')
492 || __PACKAGE__->_throw_error("Match action must be a CODE ref, not $action");
494 if ($type->check($to_match)) {
495 local $_ = $to_match;
496 return $action->($to_match);
500 || __PACKAGE__->_throw_error("No cases matched for $to_match");
502 local $_ = $to_match;
503 return $default->($to_match);
508 ## --------------------------------------------------------
509 ## desugaring functions ...
510 ## --------------------------------------------------------
512 sub _create_type_constraint ($$$;$$) {
517 my $optimized = shift;
519 my $pkg_defined_in = scalar( caller(1) );
521 if ( defined $name ) {
522 my $type = $REGISTRY->get_type_constraint($name);
524 ( $type->_package_defined_in eq $pkg_defined_in )
526 "The type constraint '$name' has already been created in "
527 . $type->_package_defined_in
528 . " and cannot be created again in "
532 $name =~ /^[\w:\.]+$/
533 or die qq{$name contains invalid characters for a type name.}
534 . qq{ Names can contain alphanumeric character, ":", and "."\n};
539 package_defined_in => $pkg_defined_in,
541 ( $check ? ( constraint => $check ) : () ),
542 ( $message ? ( message => $message ) : () ),
543 ( $optimized ? ( optimized => $optimized ) : () ),
552 : find_or_create_isa_type_constraint($parent)
554 $constraint = $parent->create_child_type(%opts);
557 $constraint = Moose::Meta::TypeConstraint->new(%opts);
560 $REGISTRY->add_type_constraint($constraint)
566 sub _install_type_coercions ($$) {
567 my ( $type_name, $coercion_map ) = @_;
568 my $type = find_type_constraint($type_name);
570 || __PACKAGE__->_throw_error(
571 "Cannot find type '$type_name', perhaps you forgot to load it");
572 if ( $type->has_coercion ) {
573 $type->coercion->add_type_coercions(@$coercion_map);
576 my $type_coercion = Moose::Meta::TypeCoercion->new(
577 type_coercion_map => $coercion_map,
578 type_constraint => $type
580 $type->coercion($type_coercion);
584 ## --------------------------------------------------------
585 ## type notation parsing ...
586 ## --------------------------------------------------------
590 # All I have to say is mugwump++ cause I know
591 # do not even have enough regexp-fu to be able
592 # to have written this (I can only barely
593 # understand it as it is)
598 my $valid_chars = qr{[\w:\.]};
599 my $type_atom = qr{ (?>$valid_chars+) }x;
600 my $ws = qr{ (?>\s*) }x;
601 my $op_union = qr{ $ws \| $ws }x;
603 my ($type, $type_capture_parts, $type_with_parameter, $union, $any);
604 if (Class::MOP::IS_RUNNING_ON_5_10) {
606 = q{ (?&type_atom) (?: \[ (?&ws) (?&any) (?&ws) \] )? };
607 my $type_capture_parts_pattern
608 = q{ ((?&type_atom)) (?: \[ (?&ws) ((?&any)) (?&ws) \] )? };
609 my $type_with_parameter_pattern
610 = q{ (?&type_atom) \[ (?&ws) (?&any) (?&ws) \] };
612 = q{ (?&type) (?> (?: (?&op_union) (?&type) )+ ) };
614 = q{ (?&type) | (?&union) };
616 my $defines = qr{(?(DEFINE)
617 (?<valid_chars> $valid_chars)
618 (?<type_atom> $type_atom)
620 (?<op_union> $op_union)
621 (?<type> $type_pattern)
622 (?<type_capture_parts> $type_capture_parts_pattern)
623 (?<type_with_parameter> $type_with_parameter_pattern)
624 (?<union> $union_pattern)
625 (?<any> $any_pattern)
628 $type = qr{ $type_pattern $defines }x;
629 $type_capture_parts = qr{ $type_capture_parts_pattern $defines }x;
630 $type_with_parameter = qr{ $type_with_parameter_pattern $defines }x;
631 $union = qr{ $union_pattern $defines }x;
632 $any = qr{ $any_pattern $defines }x;
636 = qr{ $type_atom (?: \[ $ws (??{$any}) $ws \] )? }x;
638 = qr{ ($type_atom) (?: \[ $ws ((??{$any})) $ws \] )? }x;
640 = qr{ $type_atom \[ $ws (??{$any}) $ws \] }x;
642 = qr{ $type (?> (?: $op_union $type )+ ) }x;
644 = qr{ $type | $union }x;
648 sub _parse_parameterized_type_constraint {
649 { no warnings 'void'; $any; } # force capture of interpolated lexical
650 $_[0] =~ m{ $type_capture_parts }x;
654 sub _detect_parameterized_type_constraint {
655 { no warnings 'void'; $any; } # force capture of interpolated lexical
656 $_[0] =~ m{ ^ $type_with_parameter $ }x;
659 sub _parse_type_constraint_union {
660 { no warnings 'void'; $any; } # force capture of interpolated lexical
663 while ( $given =~ m{ \G (?: $op_union )? ($type) }gcx ) {
666 ( pos($given) eq length($given) )
667 || __PACKAGE__->_throw_error( "'$given' didn't parse (parse-pos="
675 sub _detect_type_constraint_union {
676 { no warnings 'void'; $any; } # force capture of interpolated lexical
677 $_[0] =~ m{^ $type $op_union $type ( $op_union .* )? $}x;
681 ## --------------------------------------------------------
682 # define some basic built-in types
683 ## --------------------------------------------------------
685 # By making these classes immutable before creating all the types we
686 # below, we avoid repeatedly calling the slow MOP-based accessors.
688 inline_constructor => 1,
689 constructor_name => "_new",
691 # these are Class::MOP accessors, so they need inlining
692 inline_accessors => 1
693 ) for grep { $_->is_mutable }
694 map { Class::MOP::class_of($_) }
696 Moose::Meta::TypeConstraint
697 Moose::Meta::TypeConstraint::Union
698 Moose::Meta::TypeConstraint::Parameterized
699 Moose::Meta::TypeConstraint::Parameterizable
700 Moose::Meta::TypeConstraint::Class
701 Moose::Meta::TypeConstraint::Role
702 Moose::Meta::TypeConstraint::Enum
703 Moose::Meta::TypeConstraint::DuckType
704 Moose::Meta::TypeConstraint::Registry
707 type 'Any' => where {1}; # meta-type including all
708 subtype 'Item' => as 'Any'; # base-type
710 subtype 'Undef' => as 'Item' => where { !defined($_) };
711 subtype 'Defined' => as 'Item' => where { defined($_) };
713 subtype 'Bool' => as 'Item' =>
714 where { !defined($_) || $_ eq "" || "$_" eq '1' || "$_" eq '0' };
716 subtype 'Value' => as 'Defined' => where { !ref($_) } =>
717 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Value;
719 subtype 'Ref' => as 'Defined' => where { ref($_) } =>
720 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Ref;
722 subtype 'Str' => as 'Value' => where { ref(\$_) eq 'SCALAR' } =>
723 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Str;
725 subtype 'Num' => as 'Str' =>
726 where { Scalar::Util::looks_like_number($_) } =>
727 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Num;
729 subtype 'Int' => as 'Num' => where { "$_" =~ /^-?[0-9]+$/ } =>
730 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Int;
732 subtype 'CodeRef' => as 'Ref' => where { ref($_) eq 'CODE' } =>
733 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::CodeRef;
734 subtype 'RegexpRef' => as 'Ref' => where { ref($_) eq 'Regexp' } =>
736 \&Moose::Util::TypeConstraints::OptimizedConstraints::RegexpRef;
737 subtype 'GlobRef' => as 'Ref' => where { ref($_) eq 'GLOB' } =>
738 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::GlobRef;
741 # scalar filehandles are GLOB refs,
742 # but a GLOB ref is not always a filehandle
743 subtype 'FileHandle' => as 'GlobRef' => where {
744 Scalar::Util::openhandle($_) || ( blessed($_) && $_->isa("IO::Handle") );
746 \&Moose::Util::TypeConstraints::OptimizedConstraints::FileHandle;
749 # blessed(qr/.../) returns true,.. how odd
750 subtype 'Object' => as 'Ref' =>
751 where { blessed($_) && blessed($_) ne 'Regexp' } =>
752 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Object;
754 # This type is deprecated.
755 subtype 'Role' => as 'Object' => where { $_->can('does') } =>
756 optimize_as \&Moose::Util::TypeConstraints::OptimizedConstraints::Role;
758 my $_class_name_checker = sub { };
760 subtype 'ClassName' => as 'Str' =>
761 where { Class::MOP::is_class_loaded($_) } => optimize_as
762 \&Moose::Util::TypeConstraints::OptimizedConstraints::ClassName;
764 subtype 'RoleName' => as 'ClassName' => where {
765 (Class::MOP::class_of($_) || return)->isa('Moose::Meta::Role');
767 \&Moose::Util::TypeConstraints::OptimizedConstraints::RoleName;
769 ## --------------------------------------------------------
770 # parameterizable types ...
772 $REGISTRY->add_type_constraint(
773 Moose::Meta::TypeConstraint::Parameterizable->new(
775 package_defined_in => __PACKAGE__,
776 parent => find_type_constraint('Ref'),
777 constraint => sub { ref($_) eq 'SCALAR' || ref($_) eq 'REF' },
779 \&Moose::Util::TypeConstraints::OptimizedConstraints::ScalarRef,
780 constraint_generator => sub {
781 my $type_parameter = shift;
782 my $check = $type_parameter->_compiled_type_constraint;
784 return $check->(${ $_ });
790 $REGISTRY->add_type_constraint(
791 Moose::Meta::TypeConstraint::Parameterizable->new(
793 package_defined_in => __PACKAGE__,
794 parent => find_type_constraint('Ref'),
795 constraint => sub { ref($_) eq 'ARRAY' },
797 \&Moose::Util::TypeConstraints::OptimizedConstraints::ArrayRef,
798 constraint_generator => sub {
799 my $type_parameter = shift;
800 my $check = $type_parameter->_compiled_type_constraint;
802 foreach my $x (@$_) {
803 ( $check->($x) ) || return;
811 $REGISTRY->add_type_constraint(
812 Moose::Meta::TypeConstraint::Parameterizable->new(
814 package_defined_in => __PACKAGE__,
815 parent => find_type_constraint('Ref'),
816 constraint => sub { ref($_) eq 'HASH' },
818 \&Moose::Util::TypeConstraints::OptimizedConstraints::HashRef,
819 constraint_generator => sub {
820 my $type_parameter = shift;
821 my $check = $type_parameter->_compiled_type_constraint;
823 foreach my $x ( values %$_ ) {
824 ( $check->($x) ) || return;
832 $REGISTRY->add_type_constraint(
833 Moose::Meta::TypeConstraint::Parameterizable->new(
835 package_defined_in => __PACKAGE__,
836 parent => find_type_constraint('Item'),
837 constraint => sub {1},
838 constraint_generator => sub {
839 my $type_parameter = shift;
840 my $check = $type_parameter->_compiled_type_constraint;
842 return 1 if not( defined($_) ) || $check->($_);
849 my @PARAMETERIZABLE_TYPES
850 = map { $REGISTRY->get_type_constraint($_) } qw[ScalarRef ArrayRef HashRef Maybe];
852 sub get_all_parameterizable_types {@PARAMETERIZABLE_TYPES}
854 sub add_parameterizable_type {
857 && $type->isa('Moose::Meta::TypeConstraint::Parameterizable') )
858 || __PACKAGE__->_throw_error(
859 "Type must be a Moose::Meta::TypeConstraint::Parameterizable not $type"
861 push @PARAMETERIZABLE_TYPES => $type;
864 ## --------------------------------------------------------
865 # end of built-in types ...
866 ## --------------------------------------------------------
869 my @BUILTINS = list_all_type_constraints();
870 sub list_all_builtin_type_constraints {@BUILTINS}
877 goto &Moose::throw_error;
888 Moose::Util::TypeConstraints - Type constraint system for Moose
892 use Moose::Util::TypeConstraints;
898 subtype 'NaturalLessThanTen'
901 => message { "This number ($_) is not less than ten!" };
907 enum 'RGBColors' => qw(red green blue);
909 no Moose::Util::TypeConstraints;
913 This module provides Moose with the ability to create custom type
914 constraints to be used in attribute definition.
916 =head2 Important Caveat
918 This is B<NOT> a type system for Perl 5. These are type constraints,
919 and they are not used by Moose unless you tell it to. No type
920 inference is performed, expressions are not typed, etc. etc. etc.
922 A type constraint is at heart a small "check if a value is valid"
923 function. A constraint can be associated with an attribute. This
924 simplifies parameter validation, and makes your code clearer to read,
925 because you can refer to constraints by name.
927 =head2 Slightly Less Important Caveat
929 It is B<always> a good idea to quote your type names.
931 This prevents Perl from trying to execute the call as an indirect
932 object call. This can be an issue when you have a subtype with the
933 same name as a valid class.
937 subtype DateTime => as Object => where { $_->isa('DateTime') };
939 will I<just work>, while this:
942 subtype DateTime => as Object => where { $_->isa('DateTime') };
944 will fail silently and cause many headaches. The simple way to solve
945 this, as well as future proof your subtypes from classes which have
946 yet to have been created, is to quote the type name:
949 subtype 'DateTime' => as 'Object' => where { $_->isa('DateTime') };
951 =head2 Default Type Constraints
953 This module also provides a simple hierarchy for Perl 5 types, here is
954 that hierarchy represented visually.
978 B<NOTE:> Any type followed by a type parameter C<[`a]> can be
979 parameterized, this means you can say:
981 ArrayRef[Int] # an array of integers
982 HashRef[CodeRef] # a hash of str to CODE ref mappings
983 ScalarRef[Int] # a reference to an integer
984 Maybe[Str] # value may be a string, may be undefined
986 If Moose finds a name in brackets that it does not recognize as an
987 existing type, it assumes that this is a class name, for example
988 C<ArrayRef[DateTime]>.
990 B<NOTE:> Unless you parameterize a type, then it is invalid to include
991 the square brackets. I.e. C<ArrayRef[]> will be treated as a new type
992 name, I<not> as a parameterization of C<ArrayRef>.
994 B<NOTE:> The C<Undef> type constraint for the most part works
995 correctly now, but edge cases may still exist, please use it
998 B<NOTE:> The C<ClassName> type constraint does a complex package
999 existence check. This means that your class B<must> be loaded for this
1000 type constraint to pass.
1002 B<NOTE:> The C<RoleName> constraint checks a string is a I<package
1003 name> which is a role, like C<'MyApp::Role::Comparable'>.
1005 =head2 Type Constraint Naming
1007 Type name declared via this module can only contain alphanumeric
1008 characters, colons (:), and periods (.).
1010 Since the types created by this module are global, it is suggested
1011 that you namespace your types just as you would namespace your
1012 modules. So instead of creating a I<Color> type for your
1013 B<My::Graphics> module, you would call the type
1014 I<My::Graphics::Types::Color> instead.
1016 =head2 Use with Other Constraint Modules
1018 This module can play nicely with other constraint modules with some
1019 slight tweaking. The C<where> clause in types is expected to be a
1020 C<CODE> reference which checks it's first argument and returns a
1021 boolean. Since most constraint modules work in a similar way, it
1022 should be simple to adapt them to work with Moose.
1024 For instance, this is how you could use it with
1025 L<Declare::Constraints::Simple> to declare a completely new type.
1027 type 'HashOfArrayOfObjects',
1031 -values => IsArrayRef(IsObject)
1035 For more examples see the F<t/200_examples/004_example_w_DCS.t> test
1038 Here is an example of using L<Test::Deep> and it's non-test
1039 related C<eq_deeply> function.
1041 type 'ArrayOfHashOfBarsAndRandomNumbers'
1044 array_each(subhashof({
1046 random_number => ignore()
1050 For a complete example see the
1051 F<t/200_examples/005_example_w_TestDeep.t> test file.
1055 =head2 Type Constraint Constructors
1057 The following functions are used to create type constraints. They
1058 will also register the type constraints your create in a global
1059 registry that is used to look types up by name.
1061 See the L</SYNOPSIS> for an example of how to use these.
1065 =item B<< subtype 'Name' => as 'Parent' => where { } ... >>
1067 This creates a named subtype.
1069 If you provide a parent that Moose does not recognize, it will
1070 automatically create a new class type constraint for this name.
1072 When creating a named type, the C<subtype> function should either be
1073 called with the sugar helpers (C<where>, C<message>, etc), or with a
1074 name and a hashref of parameters:
1076 subtype( 'Foo', { where => ..., message => ... } );
1078 The valid hashref keys are C<as> (the parent), C<where>, C<message>,
1081 =item B<< subtype as 'Parent' => where { } ... >>
1083 This creates an unnamed subtype and will return the type
1084 constraint meta-object, which will be an instance of
1085 L<Moose::Meta::TypeConstraint>.
1087 When creating an anonymous type, the C<subtype> function should either
1088 be called with the sugar helpers (C<where>, C<message>, etc), or with
1089 just a hashref of parameters:
1091 subtype( { where => ..., message => ... } );
1093 =item B<class_type ($class, ?$options)>
1095 Creates a new subtype of C<Object> with the name C<$class> and the
1096 metaclass L<Moose::Meta::TypeConstraint::Class>.
1098 =item B<role_type ($role, ?$options)>
1100 Creates a C<Role> type constraint with the name C<$role> and the
1101 metaclass L<Moose::Meta::TypeConstraint::Role>.
1103 =item B<maybe_type ($type)>
1105 Creates a type constraint for either C<undef> or something of the
1108 =item B<duck_type ($name, \@methods)>
1110 This will create a subtype of Object and test to make sure the value
1111 C<can()> do the methods in C<\@methods>.
1113 This is intended as an easy way to accept non-Moose objects that
1114 provide a certain interface. If you're using Moose classes, we
1115 recommend that you use a C<requires>-only Role instead.
1117 =item B<duck_type (\@methods)>
1119 If passed an ARRAY reference as the only parameter instead of the
1120 C<$name>, C<\@methods> pair, this will create an unnamed duck type.
1121 This can be used in an attribute definition like so:
1125 isa => duck_type( [qw( get_set )] ),
1128 =item B<enum ($name, \@values)>
1130 This will create a basic subtype for a given set of strings.
1131 The resulting constraint will be a subtype of C<Str> and
1132 will match any of the items in C<\@values>. It is case sensitive.
1133 See the L</SYNOPSIS> for a simple example.
1135 B<NOTE:> This is not a true proper enum type, it is simply
1136 a convenient constraint builder.
1138 =item B<enum (\@values)>
1140 If passed an ARRAY reference as the only parameter instead of the
1141 C<$name>, C<\@values> pair, this will create an unnamed enum. This
1142 can then be used in an attribute definition like so:
1144 has 'sort_order' => (
1146 isa => enum([qw[ ascending descending ]]),
1149 =item B<as 'Parent'>
1151 This is just sugar for the type constraint construction syntax.
1153 It takes a single argument, which is the name of a parent type.
1155 =item B<where { ... }>
1157 This is just sugar for the type constraint construction syntax.
1159 It takes a subroutine reference as an argument. When the type
1160 constraint is tested, the reference is run with the value to be tested
1161 in C<$_>. This reference should return true or false to indicate
1162 whether or not the constraint check passed.
1164 =item B<message { ... }>
1166 This is just sugar for the type constraint construction syntax.
1168 It takes a subroutine reference as an argument. When the type
1169 constraint fails, then the code block is run with the value provided
1170 in C<$_>. This reference should return a string, which will be used in
1171 the text of the exception thrown.
1173 =item B<optimize_as { ... }>
1175 This can be used to define a "hand optimized" version of your
1176 type constraint which can be used to avoid traversing a subtype
1177 constraint hierarchy.
1179 B<NOTE:> You should only use this if you know what you are doing,
1180 all the built in types use this, so your subtypes (assuming they
1181 are shallow) will not likely need to use this.
1183 =item B<< type 'Name' => where { } ... >>
1185 This creates a base type, which has no parent.
1187 The C<type> function should either be called with the sugar helpers
1188 (C<where>, C<message>, etc), or with a name and a hashref of
1191 type( 'Foo', { where => ..., message => ... } );
1193 The valid hashref keys are C<where>, C<message>, and C<optimize_as>.
1197 =head2 Type Constraint Utilities
1201 =item B<< match_on_type $value => ( $type => \&action, ... ?\&default ) >>
1203 This is a utility function for doing simple type based dispatching similar to
1204 match/case in OCaml and case/of in Haskell. It is not as featureful as those
1205 languages, nor does not it support any kind of automatic destructuring
1206 bind. Here is a simple Perl pretty printer dispatching over the core Moose
1211 match_on_type $x => (
1216 join ", " => map { $_ . ' => ' . ppprint( $hash->{$_} ) }
1222 '[ ' . ( join ", " => map { ppprint($_) } @$array ) . ' ]';
1224 CodeRef => sub {'sub { ... }'},
1225 RegexpRef => sub { 'qr/' . $_ . '/' },
1226 GlobRef => sub { '*' . B::svref_2object($_)->NAME },
1227 Object => sub { $_->can('to_string') ? $_->to_string : $_ },
1228 ScalarRef => sub { '\\' . ppprint( ${$_} ) },
1230 Str => sub { '"' . $_ . '"' },
1231 Undef => sub {'undef'},
1232 => sub { die "I don't know what $_ is" }
1236 Or a simple JSON serializer:
1240 match_on_type $x => (
1246 map { '"' . $_ . '" : ' . to_json( $hash->{$_} ) }
1252 '[ ' . ( join ", " => map { to_json($_) } @$array ) . ' ]';
1255 Str => sub { '"' . $_ . '"' },
1256 Undef => sub {'null'},
1257 => sub { die "$_ is not acceptable json type" }
1261 The matcher is done by mapping a C<$type> to an C<\&action>. The C<$type> can
1262 be either a string type or a L<Moose::Meta::TypeConstraint> object, and
1263 C<\&action> is a subroutine reference. This function will dispatch on the
1264 first match for C<$value>. It is possible to have a catch-all by providing an
1265 additional subroutine reference as the final argument to C<match_on_type>.
1269 =head2 Type Coercion Constructors
1271 You can define coercions for type constraints, which allow you to
1272 automatically transform values to something valid for the type
1273 constraint. If you ask your accessor to coerce, then Moose will run
1274 the type-coercion code first, followed by the type constraint
1275 check. This feature should be used carefully as it is very powerful
1276 and could easily take off a limb if you are not careful.
1278 See the L</SYNOPSIS> for an example of how to use these.
1282 =item B<< coerce 'Name' => from 'OtherName' => via { ... } >>
1284 This defines a coercion from one type to another. The C<Name> argument
1285 is the type you are coercing I<to>.
1287 =item B<from 'OtherName'>
1289 This is just sugar for the type coercion construction syntax.
1291 It takes a single type name (or type object), which is the type being
1294 =item B<via { ... }>
1296 This is just sugar for the type coercion construction syntax.
1298 It takes a subroutine reference. This reference will be called with
1299 the value to be coerced in C<$_>. It is expected to return a new value
1300 of the proper type for the coercion.
1304 =head2 Creating and Finding Type Constraints
1306 These are additional functions for creating and finding type
1307 constraints. Most of these functions are not available for
1308 importing. The ones that are importable as specified.
1312 =item B<find_type_constraint($type_name)>
1314 This function can be used to locate the L<Moose::Meta::TypeConstraint>
1315 object for a named type.
1317 This function is importable.
1319 =item B<register_type_constraint($type_object)>
1321 This function will register a L<Moose::Meta::TypeConstraint> with the
1322 global type registry.
1324 This function is importable.
1326 =item B<normalize_type_constraint_name($type_constraint_name)>
1328 This method takes a type constraint name and returns the normalized
1329 form. This removes any whitespace in the string.
1331 =item B<create_type_constraint_union($pipe_separated_types | @type_constraint_names)>
1333 This can take a union type specification like C<'Int|ArrayRef[Int]'>,
1334 or a list of names. It returns a new
1335 L<Moose::Meta::TypeConstraint::Union> object.
1337 =item B<create_parameterized_type_constraint($type_name)>
1339 Given a C<$type_name> in the form of C<'BaseType[ContainerType]'>,
1340 this will create a new L<Moose::Meta::TypeConstraint::Parameterized>
1341 object. The C<BaseType> must exist already exist as a parameterizable
1344 =item B<create_class_type_constraint($class, $options)>
1346 Given a class name this function will create a new
1347 L<Moose::Meta::TypeConstraint::Class> object for that class name.
1349 The C<$options> is a hash reference that will be passed to the
1350 L<Moose::Meta::TypeConstraint::Class> constructor (as a hash).
1352 =item B<create_role_type_constraint($role, $options)>
1354 Given a role name this function will create a new
1355 L<Moose::Meta::TypeConstraint::Role> object for that role name.
1357 The C<$options> is a hash reference that will be passed to the
1358 L<Moose::Meta::TypeConstraint::Role> constructor (as a hash).
1360 =item B<create_enum_type_constraint($name, $values)>
1362 Given a enum name this function will create a new
1363 L<Moose::Meta::TypeConstraint::Enum> object for that enum name.
1365 =item B<create_duck_type_constraint($name, $methods)>
1367 Given a duck type name this function will create a new
1368 L<Moose::Meta::TypeConstraint::DuckType> object for that enum name.
1370 =item B<find_or_parse_type_constraint($type_name)>
1372 Given a type name, this first attempts to find a matching constraint
1373 in the global registry.
1375 If the type name is a union or parameterized type, it will create a
1376 new object of the appropriate, but if given a "regular" type that does
1377 not yet exist, it simply returns false.
1379 When given a union or parameterized type, the member or base type must
1382 If it creates a new union or parameterized type, it will add it to the
1385 =item B<find_or_create_isa_type_constraint($type_name)>
1387 =item B<find_or_create_does_type_constraint($type_name)>
1389 These functions will first call C<find_or_parse_type_constraint>. If
1390 that function does not return a type, a new anonymous type object will
1393 The C<isa> variant will use C<create_class_type_constraint> and the
1394 C<does> variant will use C<create_role_type_constraint>.
1396 =item B<get_type_constraint_registry>
1398 Returns the L<Moose::Meta::TypeConstraint::Registry> object which
1399 keeps track of all type constraints.
1401 =item B<list_all_type_constraints>
1403 This will return a list of type constraint names in the global
1404 registry. You can then fetch the actual type object using
1405 C<find_type_constraint($type_name)>.
1407 =item B<list_all_builtin_type_constraints>
1409 This will return a list of builtin type constraints, meaning those
1410 which are defined in this module. See the L<Default Type Constraints>
1411 section for a complete list.
1413 =item B<export_type_constraints_as_functions>
1415 This will export all the current type constraints as functions into
1416 the caller's namespace (C<Int()>, C<Str()>, etc). Right now, this is
1417 mostly used for testing, but it might prove useful to others.
1419 =item B<get_all_parameterizable_types>
1421 This returns all the parameterizable types that have been registered,
1422 as a list of type objects.
1424 =item B<add_parameterizable_type($type)>
1426 Adds C<$type> to the list of parameterizable types
1432 See L<Moose/BUGS> for details on reporting bugs.
1436 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1438 =head1 COPYRIGHT AND LICENSE
1440 Copyright 2006-2010 by Infinity Interactive, Inc.
1442 L<http://www.iinteractive.com>
1444 This library is free software; you can redistribute it and/or modify
1445 it under the same terms as Perl itself.