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package Moose::Util::TypeConstraints; our $VERSION = '2.2206'; use Carp (); use Scalar::Util qw( blessed ); use Moose::Exporter; use Moose::Deprecated; ## -------------------------------------------------------- # Prototyped subs must be predeclared because we have a # circular dependency with Moose::Meta::Attribute et. al. # so in case of us being use'd first the predeclaration # ensures the prototypes are in scope when consumers are # compiled. # dah sugah! sub where (&); sub via (&); sub message (&); sub inline_as (&); ## -------------------------------------------------------- use Moose::Meta::TypeConstraint; use Moose::Meta::TypeConstraint::Union; use Moose::Meta::TypeConstraint::Parameterized; use Moose::Meta::TypeConstraint::Parameterizable; use Moose::Meta::TypeConstraint::Class; use Moose::Meta::TypeConstraint::Role; use Moose::Meta::TypeConstraint::Enum; use Moose::Meta::TypeConstraint::DuckType; use Moose::Meta::TypeCoercion; use Moose::Meta::TypeCoercion::Union; use Moose::Meta::TypeConstraint::Registry; use Moose::Util 'throw_exception'; Moose::Exporter->setup_import_methods( as_is => [ qw( type subtype class_type role_type maybe_type duck_type as where message inline_as coerce from via enum union find_type_constraint register_type_constraint match_on_type ) ], ); ## -------------------------------------------------------- ## type registry and some useful functions for it ## -------------------------------------------------------- my $REGISTRY = Moose::Meta::TypeConstraint::Registry->new; sub get_type_constraint_registry {$REGISTRY} sub list_all_type_constraints { keys %{ $REGISTRY->type_constraints } } sub export_type_constraints_as_functions { my $pkg = caller(); no strict 'refs'; foreach my $constraint ( keys %{ $REGISTRY->type_constraints } ) { my $tc = $REGISTRY->get_type_constraint($constraint) ->_compiled_type_constraint; *{"${pkg}::${constraint}"} = sub { $tc->( $_[0] ) ? 1 : undef }; # the undef is for compat } } sub create_type_constraint_union { _create_type_constraint_union(\@_); } sub create_named_type_constraint_union { my $name = shift; _create_type_constraint_union($name, \@_); } sub _create_type_constraint_union { my $name; $name = shift if @_ > 1; my @tcs = @{ shift() }; my @type_constraint_names; if ( scalar @tcs == 1 && _detect_type_constraint_union( $tcs[0] ) ) { @type_constraint_names = _parse_type_constraint_union( $tcs[0] ); } else { @type_constraint_names = @tcs; } ( scalar @type_constraint_names >= 2 ) || throw_exception("UnionTakesAtleastTwoTypeNames"); my @type_constraints = map { find_or_parse_type_constraint($_) || throw_exception( CouldNotLocateTypeConstraintForUnion => type_name => $_ ); } @type_constraint_names; my %options = ( type_constraints => \@type_constraints ); $options{name} = $name if defined $name; return Moose::Meta::TypeConstraint::Union->new(%options); } sub create_parameterized_type_constraint { my $type_constraint_name = shift; my ( $base_type, $type_parameter ) = _parse_parameterized_type_constraint($type_constraint_name); ( defined $base_type && defined $type_parameter ) || throw_exception( InvalidTypeGivenToCreateParameterizedTypeConstraint => type_name => $type_constraint_name ); if ( $REGISTRY->has_type_constraint($base_type) ) { my $base_type_tc = $REGISTRY->get_type_constraint($base_type); return _create_parameterized_type_constraint( $base_type_tc, $type_parameter ); } else { throw_exception( InvalidBaseTypeGivenToCreateParameterizedTypeConstraint => type_name => $base_type ); } } sub _create_parameterized_type_constraint { my ( $base_type_tc, $type_parameter ) = @_; if ( $base_type_tc->can('parameterize') ) { return $base_type_tc->parameterize($type_parameter); } else { return Moose::Meta::TypeConstraint::Parameterized->new( name => $base_type_tc->name . '[' . $type_parameter . ']', parent => $base_type_tc, type_parameter => find_or_create_isa_type_constraint($type_parameter), ); } } #should we also support optimized checks? sub create_class_type_constraint { my ( $class, $options ) = @_; # too early for this check #find_type_constraint("ClassName")->check($class) # || __PACKAGE__->_throw_error("Can't create a class type constraint because '$class' is not a class name"); my $pkg_defined_in = $options->{package_defined_in} || scalar( caller(1) ); if (my $type = $REGISTRY->get_type_constraint($class)) { if (!($type->isa('Moose::Meta::TypeConstraint::Class') && $type->class eq $class)) { throw_exception( TypeConstraintIsAlreadyCreated => package_defined_in => $pkg_defined_in, type_name => $type->name, ); } else { return $type; } } my %options = ( class => $class, name => $class, package_defined_in => $pkg_defined_in, %{ $options || {} }, # overrides options from above ); $options{name} ||= "__ANON__"; my $tc = Moose::Meta::TypeConstraint::Class->new(%options); $REGISTRY->add_type_constraint($tc); return $tc; } sub create_role_type_constraint { my ( $role, $options ) = @_; # too early for this check #find_type_constraint("ClassName")->check($class) # || __PACKAGE__->_throw_error("Can't create a class type constraint because '$class' is not a class name"); my $pkg_defined_in = $options->{package_defined_in} || scalar( caller(1) ); if (my $type = $REGISTRY->get_type_constraint($role)) { if (!($type->isa('Moose::Meta::TypeConstraint::Role') && $type->role eq $role)) { throw_exception( TypeConstraintIsAlreadyCreated => type_name => $type->name, package_defined_in => $pkg_defined_in ); } else { return $type; } } my %options = ( role => $role, name => $role, package_defined_in => $pkg_defined_in, %{ $options || {} }, ); $options{name} ||= "__ANON__"; my $tc = Moose::Meta::TypeConstraint::Role->new(%options); $REGISTRY->add_type_constraint($tc); return $tc; } sub find_or_create_type_constraint { my ( $type_constraint_name, $options_for_anon_type ) = @_; if ( my $constraint = find_or_parse_type_constraint($type_constraint_name) ) { return $constraint; } elsif ( defined $options_for_anon_type ) { # NOTE: # if there is no $options_for_anon_type # specified, then we assume they don't # want to create one, and return nothing. # otherwise assume that we should create # an ANON type with the $options_for_anon_type # options which can be passed in. It should # be noted that these don't get registered # so we need to return it. # - SL return Moose::Meta::TypeConstraint->new( name => '__ANON__', %{$options_for_anon_type} ); } return; } sub find_or_create_isa_type_constraint { my ($type_constraint_name, $options) = @_; find_or_parse_type_constraint($type_constraint_name) || create_class_type_constraint($type_constraint_name, $options); } sub find_or_create_does_type_constraint { my ($type_constraint_name, $options) = @_; find_or_parse_type_constraint($type_constraint_name) || create_role_type_constraint($type_constraint_name, $options); } sub find_or_parse_type_constraint { my $type_constraint_name = normalize_type_constraint_name(shift); my $constraint; if ( $constraint = find_type_constraint($type_constraint_name) ) { return $constraint; } elsif ( _detect_type_constraint_union($type_constraint_name) ) { $constraint = create_type_constraint_union($type_constraint_name); } elsif ( _detect_parameterized_type_constraint($type_constraint_name) ) { $constraint = create_parameterized_type_constraint($type_constraint_name); } else { return; } $REGISTRY->add_type_constraint($constraint); return $constraint; } sub normalize_type_constraint_name { my $type_constraint_name = shift; $type_constraint_name =~ s/\s//g; return $type_constraint_name; } sub _confess { my $error = shift; local $Carp::CarpLevel = $Carp::CarpLevel + 1; Carp::confess($error); } ## -------------------------------------------------------- ## exported functions ... ## -------------------------------------------------------- sub find_type_constraint { my $type = shift; if ( blessed $type and $type->isa("Moose::Meta::TypeConstraint") ) { return $type; } else { return unless $REGISTRY->has_type_constraint($type); return $REGISTRY->get_type_constraint($type); } } sub register_type_constraint { my $constraint = shift; throw_exception( CannotRegisterUnnamedTypeConstraint => type => $constraint ) unless defined $constraint->name; $REGISTRY->add_type_constraint($constraint); return $constraint; } # type constructors sub type { my $name = shift; my %p = map { %{$_} } @_; return _create_type_constraint( $name, undef, $p{where}, $p{message}, $p{inline_as}, ); } sub subtype { if ( @_ == 1 && !ref $_[0] ) { throw_exception( NoParentGivenToSubtype => name => $_[0] ); } # The blessed check is mostly to accommodate MooseX::Types, which # uses an object which overloads stringification as a type name. my $name = ref $_[0] && !blessed $_[0] ? undef : shift; my %p = map { %{$_} } @_; # subtype Str => where { ... }; if ( !exists $p{as} ) { $p{as} = $name; $name = undef; } return _create_type_constraint( $name, $p{as}, $p{where}, $p{message}, $p{inline_as}, ); } sub class_type { create_class_type_constraint(@_); } sub role_type ($;$) { create_role_type_constraint(@_); } sub maybe_type { my ($type_parameter) = @_; register_type_constraint( $REGISTRY->get_type_constraint('Maybe')->parameterize($type_parameter) ); } sub duck_type { my ( $type_name, @methods ) = @_; if ( ref $type_name eq 'ARRAY' && !@methods ) { @methods = ($type_name); $type_name = undef; } if ( @methods == 1 && ref $methods[0] eq 'ARRAY' ) { @methods = @{ $methods[0] }; } else { Moose::Deprecated::deprecated( feature => 'non-arrayref form of duck_type', message => "Passing a list of values to duck_type is deprecated. " . "The method names should be wrapped in an arrayref.", ); } register_type_constraint( create_duck_type_constraint( $type_name, \@methods, ) ); } sub coerce { my ( $type_name, @coercion_map ) = @_; _install_type_coercions( $type_name, \@coercion_map ); } # The trick of returning @_ lets us avoid having to specify a # prototype. Perl will parse this: # # subtype 'Foo' # => as 'Str' # => where { ... } # # as this: # # subtype( 'Foo', as( 'Str', where { ... } ) ); # # If as() returns all its extra arguments, this just works, and # preserves backwards compatibility. sub as { +{ as => shift }, @_ } sub where (&) { +{ where => $_[0] } } sub message (&) { +{ message => $_[0] } } sub inline_as (&) { +{ inline_as => $_[0] } } sub from { @_ } sub via (&) { $_[0] } sub enum { my ( $type_name, @values ) = @_; # NOTE: # if only an array-ref is passed then # you get an anon-enum # - SL if ( ref $type_name eq 'ARRAY' ) { @values == 0 || throw_exception( EnumCalledWithAnArrayRefAndAdditionalArgs => array => $type_name, args => \@values ); @values = ($type_name); $type_name = undef; } if ( @values == 1 && ref $values[0] eq 'ARRAY' ) { @values = @{ $values[0] }; } else { Moose::Deprecated::deprecated( feature => 'non-arrayref form of enum', message => "Passing a list of values to enum is deprecated. " . "Enum values should be wrapped in an arrayref.", ); } register_type_constraint( create_enum_type_constraint( $type_name, \@values, ) ); } sub union { my ( $type_name, @constraints ) = @_; if ( ref $type_name eq 'ARRAY' ) { @constraints == 0 || throw_exception( UnionCalledWithAnArrayRefAndAdditionalArgs => array => $type_name, args => \@constraints ); @constraints = @$type_name; $type_name = undef; } if ( @constraints == 1 && ref $constraints[0] eq 'ARRAY' ) { @constraints = @{ $constraints[0] }; } if ( defined $type_name ) { return register_type_constraint( create_named_type_constraint_union( $type_name, @constraints ) ); } return create_type_constraint_union( @constraints ); } sub create_enum_type_constraint { my ( $type_name, $values ) = @_; Moose::Meta::TypeConstraint::Enum->new( name => $type_name || '__ANON__', values => $values, ); } sub create_duck_type_constraint { my ( $type_name, $methods ) = @_; Moose::Meta::TypeConstraint::DuckType->new( name => $type_name || '__ANON__', methods => $methods, ); } sub match_on_type { my ($to_match, @cases) = @_; my $default; if (@cases % 2 != 0) { $default = pop @cases; (ref $default eq 'CODE') || throw_exception( DefaultToMatchOnTypeMustBeCodeRef => to_match => $to_match, default_action => $default, cases_to_be_matched => \@cases ); } while (@cases) { my ($type, $action) = splice @cases, 0, 2; unless (blessed $type && $type->isa('Moose::Meta::TypeConstraint')) { $type = find_or_parse_type_constraint($type) || throw_exception( CannotFindTypeGivenToMatchOnType => type => $type, to_match => $to_match, action => $action ); } (ref $action eq 'CODE') || throw_exception( MatchActionMustBeACodeRef => type_name => $type->name, action => $action, to_match => $to_match ); if ($type->check($to_match)) { local $_ = $to_match; return $action->($to_match); } } (defined $default) || throw_exception( NoCasesMatched => to_match => $to_match, cases_to_be_matched => \@cases ); { local $_ = $to_match; return $default->($to_match); } } ## -------------------------------------------------------- ## desugaring functions ... ## -------------------------------------------------------- sub _create_type_constraint ($$$;$) { my $name = shift; my $parent = shift; my $check = shift; my $message = shift; my $inlined = shift; my $pkg_defined_in = scalar( caller(1) ); if ( defined $name ) { my $type = $REGISTRY->get_type_constraint($name); ( $type->_package_defined_in eq $pkg_defined_in ) || throw_exception( TypeConstraintIsAlreadyCreated => package_defined_in => $pkg_defined_in, type_name => $type->name, ) if defined $type; if( $name !~ /^[\w:\.]+$/ ) { throw_exception( InvalidNameForType => name => $name ); } } my %opts = ( name => $name, package_defined_in => $pkg_defined_in, ( $check ? ( constraint => $check ) : () ), ( $message ? ( message => $message ) : () ), ( $inlined ? ( inlined => $inlined ) : () ), ); my $constraint; if ( defined $parent and $parent = blessed $parent ? $parent : find_or_create_isa_type_constraint($parent) ) { $constraint = $parent->create_child_type(%opts); } else { $constraint = Moose::Meta::TypeConstraint->new(%opts); } $REGISTRY->add_type_constraint($constraint) if defined $name; return $constraint; } sub _install_type_coercions ($$) { my ( $type_name, $coercion_map ) = @_; my $type = find_type_constraint($type_name); ( defined $type ) || throw_exception( CannotFindType => type_name => $type_name ); if ( $type->has_coercion ) { $type->coercion->add_type_coercions(@$coercion_map); } else { my $type_coercion = Moose::Meta::TypeCoercion->new( type_coercion_map => $coercion_map, type_constraint => $type ); $type->coercion($type_coercion); } } ## -------------------------------------------------------- ## type notation parsing ... ## -------------------------------------------------------- { # All I have to say is mugwump++ cause I know # do not even have enough regexp-fu to be able # to have written this (I can only barely # understand it as it is) # - SL use re "eval"; my $valid_chars = qr{[\w:\.]}; my $type_atom = qr{ (?>$valid_chars+) }x; my $ws = qr{ (?>\s*) }x; my $op_union = qr{ $ws \| $ws }x; my ($type, $type_capture_parts, $type_with_parameter, $union, $any); if (Class::MOP::IS_RUNNING_ON_5_10) { my $type_pattern = q{ (?&type_atom) (?: \[ (?&ws) (?&any) (?&ws) \] )? }; my $type_capture_parts_pattern = q{ ((?&type_atom)) (?: \[ (?&ws) ((?&any)) (?&ws) \] )? }; my $type_with_parameter_pattern = q{ (?&type_atom) \[ (?&ws) (?&any) (?&ws) \] }; my $union_pattern = q{ (?&type) (?> (?: (?&op_union) (?&type) )+ ) }; my $any_pattern = q{ (?&type) | (?&union) }; my $defines = qr{(?(DEFINE) (?<valid_chars> $valid_chars) (?<type_atom> $type_atom) (?<ws> $ws) (?<op_union> $op_union) (?<type> $type_pattern) (?<type_capture_parts> $type_capture_parts_pattern) (?<type_with_parameter> $type_with_parameter_pattern) (?<union> $union_pattern) (?<any> $any_pattern) )}x; $type = qr{ $type_pattern $defines }x; $type_capture_parts = qr{ $type_capture_parts_pattern $defines }x; $type_with_parameter = qr{ $type_with_parameter_pattern $defines }x; $union = qr{ $union_pattern $defines }x; $any = qr{ $any_pattern $defines }x; } else { $type = qr{ $type_atom (?: \[ $ws (??{$any}) $ws \] )? }x; $type_capture_parts = qr{ ($type_atom) (?: \[ $ws ((??{$any})) $ws \] )? }x; $type_with_parameter = qr{ $type_atom \[ $ws (??{$any}) $ws \] }x; $union = qr{ $type (?> (?: $op_union $type )+ ) }x; $any = qr{ $type | $union }x; } sub _parse_parameterized_type_constraint { { no warnings 'void'; $any; } # force capture of interpolated lexical $_[0] =~ m{ $type_capture_parts }x; return ( $1, $2 ); } sub _detect_parameterized_type_constraint { { no warnings 'void'; $any; } # force capture of interpolated lexical $_[0] =~ m{ ^ $type_with_parameter $ }x; } sub _parse_type_constraint_union { { no warnings 'void'; $any; } # force capture of interpolated lexical my $given = shift; my @rv; while ( $given =~ m{ \G (?: $op_union )? ($type) }gcx ) { push @rv => $1; } ( pos($given) eq length($given) ) || throw_exception( CouldNotParseType => type => $given, position => pos($given) ); @rv; } sub _detect_type_constraint_union { { no warnings 'void'; $any; } # force capture of interpolated lexical $_[0] =~ m{^ $type $op_union $type ( $op_union .* )? $}x; } } ## -------------------------------------------------------- # define some basic built-in types ## -------------------------------------------------------- # By making these classes immutable before creating all the types in # Moose::Util::TypeConstraints::Builtin , we avoid repeatedly calling the slow # MOP-based accessors. $_->make_immutable( inline_constructor => 1, constructor_name => "_new", # these are Class::MOP accessors, so they need inlining inline_accessors => 1 ) for grep { $_->is_mutable } map { Class::MOP::class_of($_) } qw( Moose::Meta::TypeConstraint Moose::Meta::TypeConstraint::Union Moose::Meta::TypeConstraint::Parameterized Moose::Meta::TypeConstraint::Parameterizable Moose::Meta::TypeConstraint::Class Moose::Meta::TypeConstraint::Role Moose::Meta::TypeConstraint::Enum Moose::Meta::TypeConstraint::DuckType Moose::Meta::TypeConstraint::Registry ); require Moose::Util::TypeConstraints::Builtins; Moose::Util::TypeConstraints::Builtins::define_builtins($REGISTRY); my @PARAMETERIZABLE_TYPES = map { $REGISTRY->get_type_constraint($_) } qw[ScalarRef ArrayRef HashRef Maybe]; sub get_all_parameterizable_types {@PARAMETERIZABLE_TYPES} sub add_parameterizable_type { my $type = shift; ( blessed $type && $type->isa('Moose::Meta::TypeConstraint::Parameterizable') ) || throw_exception( AddParameterizableTypeTakesParameterizableType => type_name => $type ); push @PARAMETERIZABLE_TYPES => $type; } ## -------------------------------------------------------- # end of built-in types ... ## -------------------------------------------------------- { my @BUILTINS = list_all_type_constraints(); sub list_all_builtin_type_constraints {@BUILTINS} } 1; # ABSTRACT: Type constraint system for Moose __END__ =pod =encoding UTF-8 =head1 NAME Moose::Util::TypeConstraints - Type constraint system for Moose =head1 VERSION version 2.2206 =head1 SYNOPSIS use Moose::Util::TypeConstraints; subtype 'Natural', as 'Int', where { $_ > 0 }; subtype 'NaturalLessThanTen', as 'Natural', where { $_ < 10 }, message { "This number ($_) is not less than ten!" }; coerce 'Num', from 'Str', via { 0+$_ }; class_type 'DateTimeClass', { class => 'DateTime' }; role_type 'Barks', { role => 'Some::Library::Role::Barks' }; enum 'RGBColors', [qw(red green blue)]; union 'StringOrArray', [qw( String ArrayRef )]; no Moose::Util::TypeConstraints; =head1 DESCRIPTION This module provides Moose with the ability to create custom type constraints to be used in attribute definition. =head2 Important Caveat This is B<NOT> a type system for Perl 5. These are type constraints, and they are not used by Moose unless you tell it to. No type inference is performed, expressions are not typed, etc. etc. etc. A type constraint is at heart a small "check if a value is valid" function. A constraint can be associated with an attribute. This simplifies parameter validation, and makes your code clearer to read, because you can refer to constraints by name. =head2 Slightly Less Important Caveat It is B<always> a good idea to quote your type names. This prevents Perl from trying to execute the call as an indirect object call. This can be an issue when you have a subtype with the same name as a valid class. For instance: subtype DateTime => as Object => where { $_->isa('DateTime') }; will I<just work>, while this: use DateTime; subtype DateTime => as Object => where { $_->isa('DateTime') }; will fail silently and cause many headaches. The simple way to solve this, as well as future proof your subtypes from classes which have yet to have been created, is to quote the type name: use DateTime; subtype 'DateTime', as 'Object', where { $_->isa('DateTime') }; =head2 Default Type Constraints This module also provides a simple hierarchy for Perl 5 types, here is that hierarchy represented visually. Any Item Bool Maybe[`a] Undef Defined Value Str Num Int ClassName RoleName Ref ScalarRef[`a] ArrayRef[`a] HashRef[`a] CodeRef RegexpRef GlobRef FileHandle Object B<NOTE:> Any type followed by a type parameter C<[`a]> can be parameterized, this means you can say: ArrayRef[Int] # an array of integers HashRef[CodeRef] # a hash of str to CODE ref mappings ScalarRef[Int] # a reference to an integer Maybe[Str] # value may be a string, may be undefined If Moose finds a name in brackets that it does not recognize as an existing type, it assumes that this is a class name, for example C<ArrayRef[DateTime]>. B<NOTE:> Unless you parameterize a type, then it is invalid to include the square brackets. I.e. C<ArrayRef[]> will be treated as a new type name, I<not> as a parameterization of C<ArrayRef>. B<NOTE:> The C<Undef> type constraint for the most part works correctly now, but edge cases may still exist, please use it sparingly. B<NOTE:> The C<ClassName> type constraint does a complex package existence check. This means that your class B<must> be loaded for this type constraint to pass. B<NOTE:> The C<RoleName> constraint checks a string is a I<package name> which is a role, like C<'MyApp::Role::Comparable'>. =head2 Type Constraint Naming Type names declared via this module can only contain alphanumeric characters, colons (:), and periods (.). Since the types created by this module are global, it is suggested that you namespace your types just as you would namespace your modules. So instead of creating a I<Color> type for your B<My::Graphics> module, you would call the type I<My::Graphics::Types::Color> instead. =head2 Use with Other Constraint Modules This module can play nicely with other constraint modules with some slight tweaking. The C<where> clause in types is expected to be a C<CODE> reference which checks its first argument and returns a boolean. Since most constraint modules work in a similar way, it should be simple to adapt them to work with Moose. For instance, this is how you could use it with L<Declare::Constraints::Simple> to declare a completely new type. type 'HashOfArrayOfObjects', where { IsHashRef( -keys => HasLength, -values => IsArrayRef(IsObject) )->(@_); }; For more examples see the F<t/examples/example_w_DCS.t> test file. Here is an example of using L<Test::Deep> and its non-test related C<eq_deeply> function. type 'ArrayOfHashOfBarsAndRandomNumbers', where { eq_deeply($_, array_each(subhashof({ bar => isa('Bar'), random_number => ignore() }))) }; For a complete example see the F<t/examples/example_w_TestDeep.t> test file. =head2 Error messages Type constraints can also specify custom error messages, for when they fail to validate. This is provided as just another coderef, which receives the invalid value in C<$_>, as in: subtype 'PositiveInt', as 'Int', where { $_ > 0 }, message { "$_ is not a positive integer!" }; If no message is specified, a default message will be used, which indicates which type constraint was being used and what value failed. If L<Devel::PartialDump> (version 0.14 or higher) is installed, it will be used to display the invalid value, otherwise it will just be printed as is. =head1 FUNCTIONS =head2 Type Constraint Constructors The following functions are used to create type constraints. They will also register the type constraints your create in a global registry that is used to look types up by name. See the L</SYNOPSIS> for an example of how to use these. =head3 subtype 'Name', as 'Parent', where { } ... This creates a named subtype. If you provide a parent that Moose does not recognize, it will automatically create a new class type constraint for this name. When creating a named type, the C<subtype> function should either be called with the sugar helpers (C<where>, C<message>, etc), or with a name and a hashref of parameters: subtype( 'Foo', { where => ..., message => ... } ); The valid hashref keys are C<as> (the parent), C<where>, C<message>, and C<inline_as>. =head3 subtype as 'Parent', where { } ... This creates an unnamed subtype and will return the type constraint meta-object, which will be an instance of L<Moose::Meta::TypeConstraint>. When creating an anonymous type, the C<subtype> function should either be called with the sugar helpers (C<where>, C<message>, etc), or with just a hashref of parameters: subtype( { where => ..., message => ... } ); =head3 class_type ($class, ?$options) Creates a new subtype of C<Object> with the name C<$class> and the metaclass L<Moose::Meta::TypeConstraint::Class>. # Create a type called 'Box' which tests for objects which ->isa('Box') class_type 'Box'; By default, the name of the type and the name of the class are the same, but you can specify both separately. # Create a type called 'Box' which tests for objects which ->isa('ObjectLibrary::Box'); class_type 'Box', { class => 'ObjectLibrary::Box' }; =head3 role_type ($role, ?$options) Creates a C<Role> type constraint with the name C<$role> and the metaclass L<Moose::Meta::TypeConstraint::Role>. # Create a type called 'Walks' which tests for objects which ->does('Walks') role_type 'Walks'; By default, the name of the type and the name of the role are the same, but you can specify both separately. # Create a type called 'Walks' which tests for objects which ->does('MooseX::Role::Walks'); role_type 'Walks', { role => 'MooseX::Role::Walks' }; =head3 maybe_type ($type) Creates a type constraint for either C<undef> or something of the given type. =head3 duck_type ($name, \@methods) This will create a subtype of Object and test to make sure the value C<can()> do the methods in C<\@methods>. This is intended as an easy way to accept non-Moose objects that provide a certain interface. If you're using Moose classes, we recommend that you use a C<requires>-only Role instead. =head3 duck_type (\@methods) If passed an ARRAY reference as the only parameter instead of the C<$name>, C<\@methods> pair, this will create an unnamed duck type. This can be used in an attribute definition like so: has 'cache' => ( is => 'ro', isa => duck_type( [qw( get_set )] ), ); =head3 enum ($name, \@values) This will create a basic subtype for a given set of strings. The resulting constraint will be a subtype of C<Str> and will match any of the items in C<\@values>. It is case sensitive. See the L</SYNOPSIS> for a simple example. B<NOTE:> This is not a true proper enum type, it is simply a convenient constraint builder. =head3 enum (\@values) If passed an ARRAY reference as the only parameter instead of the C<$name>, C<\@values> pair, this will create an unnamed enum. This can then be used in an attribute definition like so: has 'sort_order' => ( is => 'ro', isa => enum([qw[ ascending descending ]]), ); =head3 union ($name, \@constraints) This will create a basic subtype where any of the provided constraints may match in order to satisfy this constraint. =head3 union (\@constraints) If passed an ARRAY reference as the only parameter instead of the C<$name>, C<\@constraints> pair, this will create an unnamed union. This can then be used in an attribute definition like so: has 'items' => ( is => 'ro', isa => union([qw[ Str ArrayRef ]]), ); This is similar to the existing string union: isa => 'Str|ArrayRef' except that it supports anonymous elements as child constraints: has 'color' => ( isa => 'ro', isa => union([ 'Int', enum([qw[ red green blue ]]) ]), ); =head3 as 'Parent' This is just sugar for the type constraint construction syntax. It takes a single argument, which is the name of a parent type. =head3 where { ... } This is just sugar for the type constraint construction syntax. It takes a subroutine reference as an argument. When the type constraint is tested, the reference is run with the value to be tested in C<$_>. This reference should return true or false to indicate whether or not the constraint check passed. =head3 message { ... } This is just sugar for the type constraint construction syntax. It takes a subroutine reference as an argument. When the type constraint fails, then the code block is run with the value provided in C<$_>. This reference should return a string, which will be used in the text of the exception thrown. =head3 inline_as { ... } This can be used to define a "hand optimized" inlinable version of your type constraint. You provide a subroutine which will be called I<as a method> on a L<Moose::Meta::TypeConstraint> object. It will receive a single parameter, the name of the variable to check, typically something like C<"$_"> or C<"$_[0]">. The subroutine should return a code string suitable for inlining. You can assume that the check will be wrapped in parentheses when it is inlined. The inlined code should include any checks that your type's parent types do. If your parent type constraint defines its own inlining, you can simply use that to avoid repeating code. For example, here is the inlining code for the C<Value> type, which is a subtype of C<Defined>: sub { $_[0]->parent()->_inline_check($_[1]) . ' && !ref(' . $_[1] . ')' } =head3 type 'Name', where { } ... This creates a base type, which has no parent. The C<type> function should either be called with the sugar helpers (C<where>, C<message>, etc), or with a name and a hashref of parameters: type( 'Foo', { where => ..., message => ... } ); The valid hashref keys are C<where>, C<message>, and C<inlined_as>. =head2 Type Constraint Utilities =head3 match_on_type $value => ( $type => \&action, ... ?\&default ) This is a utility function for doing simple type based dispatching similar to match/case in OCaml and case/of in Haskell. It is not as featureful as those languages, nor does not it support any kind of automatic destructuring bind. Here is a simple Perl pretty printer dispatching over the core Moose types. sub ppprint { my $x = shift; match_on_type $x => ( HashRef => sub { my $hash = shift; '{ ' . ( join ", " => map { $_ . ' => ' . ppprint( $hash->{$_} ) } sort keys %$hash ) . ' }'; }, ArrayRef => sub { my $array = shift; '[ ' . ( join ", " => map { ppprint($_) } @$array ) . ' ]'; }, CodeRef => sub {'sub { ... }'}, RegexpRef => sub { 'qr/' . $_ . '/' }, GlobRef => sub { '*' . B::svref_2object($_)->NAME }, Object => sub { $_->can('to_string') ? $_->to_string : $_ }, ScalarRef => sub { '\\' . ppprint( ${$_} ) }, Num => sub {$_}, Str => sub { '"' . $_ . '"' }, Undef => sub {'undef'}, => sub { die "I don't know what $_ is" } ); } Or a simple JSON serializer: sub to_json { my $x = shift; match_on_type $x => ( HashRef => sub { my $hash = shift; '{ ' . ( join ", " => map { '"' . $_ . '" : ' . to_json( $hash->{$_} ) } sort keys %$hash ) . ' }'; }, ArrayRef => sub { my $array = shift; '[ ' . ( join ", " => map { to_json($_) } @$array ) . ' ]'; }, Num => sub {$_}, Str => sub { '"' . $_ . '"' }, Undef => sub {'null'}, => sub { die "$_ is not acceptable json type" } ); } The matcher is done by mapping a C<$type> to an C<\&action>. The C<$type> can be either a string type or a L<Moose::Meta::TypeConstraint> object, and C<\&action> is a subroutine reference. This function will dispatch on the first match for C<$value>. It is possible to have a catch-all by providing an additional subroutine reference as the final argument to C<match_on_type>. =head2 Type Coercion Constructors You can define coercions for type constraints, which allow you to automatically transform values to something valid for the type constraint. If you ask your accessor to coerce by adding the option C<< coerce => 1 >>, then Moose will run the type-coercion code first, followed by the type constraint check. This feature should be used carefully as it is very powerful and could easily take off a limb if you are not careful. See the L</SYNOPSIS> for an example of how to use these. =head3 coerce 'Name', from 'OtherName', via { ... } This defines a coercion from one type to another. The C<Name> argument is the type you are coercing I<to>. To define multiple coercions, supply more sets of from/via pairs: coerce 'Name', from 'OtherName', via { ... }, from 'ThirdName', via { ... }; =head3 from 'OtherName' This is just sugar for the type coercion construction syntax. It takes a single type name (or type object), which is the type being coerced I<from>. =head3 via { ... } This is just sugar for the type coercion construction syntax. It takes a subroutine reference. This reference will be called with the value to be coerced in C<$_>. It is expected to return a new value of the proper type for the coercion. =head2 Creating and Finding Type Constraints These are additional functions for creating and finding type constraints. Most of these functions are not available for importing. The ones that are importable as specified. =head3 find_type_constraint($type_name) This function can be used to locate the L<Moose::Meta::TypeConstraint> object for a named type. This function is importable. =head3 register_type_constraint($type_object) This function will register a L<Moose::Meta::TypeConstraint> with the global type registry. This function is importable. =head3 normalize_type_constraint_name($type_constraint_name) This method takes a type constraint name and returns the normalized form. This removes any whitespace in the string. =head3 create_type_constraint_union($pipe_separated_types | @type_constraint_names) =head3 create_named_type_constraint_union($name, $pipe_separated_types | @type_constraint_names) This can take a union type specification like C<'Int|ArrayRef[Int]'>, or a list of names. It returns a new L<Moose::Meta::TypeConstraint::Union> object. =head3 create_parameterized_type_constraint($type_name) Given a C<$type_name> in the form of C<'BaseType[ContainerType]'>, this will create a new L<Moose::Meta::TypeConstraint::Parameterized> object. The C<BaseType> must already exist as a parameterizable type. =head3 create_class_type_constraint($class, $options) Given a class name this function will create a new L<Moose::Meta::TypeConstraint::Class> object for that class name. The C<$options> is a hash reference that will be passed to the L<Moose::Meta::TypeConstraint::Class> constructor (as a hash). =head3 create_role_type_constraint($role, $options) Given a role name this function will create a new L<Moose::Meta::TypeConstraint::Role> object for that role name. The C<$options> is a hash reference that will be passed to the L<Moose::Meta::TypeConstraint::Role> constructor (as a hash). =head3 create_enum_type_constraint($name, $values) Given a enum name this function will create a new L<Moose::Meta::TypeConstraint::Enum> object for that enum name. =head3 create_duck_type_constraint($name, $methods) Given a duck type name this function will create a new L<Moose::Meta::TypeConstraint::DuckType> object for that enum name. =head3 find_or_parse_type_constraint($type_name) Given a type name, this first attempts to find a matching constraint in the global registry. If the type name is a union or parameterized type, it will create a new object of the appropriate, but if given a "regular" type that does not yet exist, it simply returns false. When given a union or parameterized type, the member or base type must already exist. If it creates a new union or parameterized type, it will add it to the global registry. =head3 find_or_create_isa_type_constraint($type_name) =head3 find_or_create_does_type_constraint($type_name) These functions will first call C<find_or_parse_type_constraint>. If that function does not return a type, a new type object will be created. The C<isa> variant will use C<create_class_type_constraint> and the C<does> variant will use C<create_role_type_constraint>. =head3 get_type_constraint_registry Returns the L<Moose::Meta::TypeConstraint::Registry> object which keeps track of all type constraints. =head3 list_all_type_constraints This will return a list of type constraint names in the global registry. You can then fetch the actual type object using C<find_type_constraint($type_name)>. =head3 list_all_builtin_type_constraints This will return a list of builtin type constraints, meaning those which are defined in this module. See the L<Default Type Constraints> section for a complete list. =head3 export_type_constraints_as_functions This will export all the current type constraints as functions into the caller's namespace (C<Int()>, C<Str()>, etc). Right now, this is mostly used for testing, but it might prove useful to others. =head3 get_all_parameterizable_types This returns all the parameterizable types that have been registered, as a list of type objects. =head3 add_parameterizable_type($type) Adds C<$type> to the list of parameterizable types =head1 BUGS See L<Moose/BUGS> for details on reporting bugs. =head1 AUTHORS =over 4 =item * Stevan Little <stevan@cpan.org> =item * Dave Rolsky <autarch@urth.org> =item * Jesse Luehrs <doy@cpan.org> =item * Shawn M Moore <sartak@cpan.org> =item * יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org> =item * Karen Etheridge <ether@cpan.org> =item * Florian Ragwitz <rafl@debian.org> =item * Hans Dieter Pearcey <hdp@cpan.org> =item * Chris Prather <chris@prather.org> =item * Matt S Trout <mstrout@cpan.org> =back =head1 COPYRIGHT AND LICENSE This software is copyright (c) 2006 by Infinity Interactive, Inc. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. =cut