6 MooseX::Types - Organise your Moose types in libraries
13 use Moose::Util::TypeConstraints;
14 use MooseX::Types::TypeDecorator;
15 use MooseX::Types::Base ();
16 use MooseX::Types::Util qw( filter_tags );
17 use MooseX::Types::UndefinedType;
18 use Carp::Clan qw( ^MooseX::Types );
20 use namespace::clean -except => [qw( meta )];
24 my $UndefMsg = q{Action for type '%s' not yet defined in library '%s'};
28 =head2 Library Definition
32 # predeclare our own types
35 PositiveInt NegativeInt
36 ArrayRefOfPositiveInt ArrayRefOfAtLeastThreeNegativeInts
37 LotsOfInnerConstraints StrOrArrayRef
40 # import builtin types
41 use MooseX::Types::Moose 'Int';
47 message { "Int is not larger than 0" };
52 message { "Int is not smaller than 0" };
59 # with parameterized constraints.
61 subtype ArrayRefOfPositiveInt,
62 as ArrayRef[PositiveInt];
64 subtype ArrayRefOfAtLeastThreeNegativeInts,
65 as ArrayRef[NegativeInt],
66 where { scalar(@$_) > 2 };
68 subtype LotsOfInnerConstraints,
69 as ArrayRef[ArrayRef[HashRef[Int]]];
71 # with TypeConstraint Unions
73 subtype StrOrArrayRef,
82 use MyLibrary qw( PositiveInt NegativeInt );
84 # use the exported constants as type names
96 print "positive\n" if is_PositiveInt($value);
97 print "negative\n" if is_NegativeInt($value);
99 # coerce the value, NegativeInt doesn't have a coercion
100 # helper, since it didn't define any coercions.
101 $value = to_PositiveInt($value) or die "Cannot coerce";
108 The types provided with L<Moose> are by design global. This package helps
109 you to organise and selectively import your own and the built-in types in
110 libraries. As a nice side effect, it catches typos at compile-time too.
112 However, the main reason for this module is to provide an easy way to not
113 have conflicts with your type names, since the internal fully qualified
114 names of the types will be prefixed with the library's name.
116 This module will also provide you with some helper functions to make it
117 easier to use Moose types in your code.
119 =head1 TYPE HANDLER FUNCTIONS
123 A constant with the name of your type. It contains the type's fully
124 qualified name. Takes no value, as all constants.
128 This handler takes a value and tests if it is a valid value for this
129 C<$type>. It will return true or false.
133 A handler that will take a value and coerce it into the C<$type>. It will
134 return a false value if the type could not be coerced.
136 B<Important Note>: This handler will only be exported for types that can
137 do type coercion. This has the advantage that a coercion to a type that
138 cannot hasn't defined any coercions will lead to a compile-time error.
140 =head1 LIBRARY DEFINITION
142 A MooseX::Types is just a normal Perl module. Unlike Moose
143 itself, it does not install C<use strict> and C<use warnings> in your
144 class by default, so this is up to you.
146 The only thing a library is required to do is
148 use MooseX::Types -declare => \@types;
150 with C<@types> being a list of types you wish to define in this library.
151 This line will install a proper base class in your package as well as the
152 full set of L<handlers|/"TYPE HANDLER FUNCTIONS"> for your declared
153 types. It will then hand control over to L<Moose::Util::TypeConstraints>'
154 C<import> method to export the functions you will need to declare your
157 If you want to use Moose' built-in types (e.g. for subtyping) you will
160 use MooseX::Types::Moose @types;
162 to import the helpers from the shipped L<MooseX::Types::Moose>
163 library which can export all types that come with Moose.
165 You will have to define coercions for your types or your library won't
166 export a L</to_$type> coercion helper for it.
168 Note that you currently cannot define types containing C<::>, since
169 exporting would be a problem.
171 You also don't need to use C<warnings> and C<strict>, since the
172 definition of a library automatically exports those.
176 You can import the L<"type helpers"|/"TYPE HANDLER FUNCTIONS"> of a
177 library by C<use>ing it with a list of types to import as arguments. If
178 you want all of them, use the C<:all> tag. For example:
180 use MyLibrary ':all';
181 use MyOtherLibrary qw( TypeA TypeB );
183 MooseX::Types comes with a library of Moose' built-in types called
184 L<MooseX::Types::Moose>.
186 The exporting mechanism is, since version 0.5, implemented via a wrapper
187 around L<Sub::Exporter>. This means you can do something like this:
189 use MyLibrary TypeA => { -as => 'MyTypeA' },
190 TypeB => { -as => 'MyTypeB' };
192 =head1 WRAPPING A LIBRARY
194 You can define your own wrapper subclasses to manipulate the behaviour
195 of a set of library exports. Here is an example:
200 use base 'MooseX::Types::Wrapper';
202 sub coercion_export_generator {
204 my $code = $class->next::method(@_);
206 my $value = $code->(@_);
207 warn "Coercion returned undef!"
208 unless defined $value;
215 This class wraps the coercion generator (e.g., C<to_Int()>) and warns
216 if a coercion returned an undefined value. You can wrap any library
221 use MyWrapper MyLibrary => [qw( Foo Bar )],
222 Moose => [qw( Str Int )];
227 The C<Moose> library name is a special shortcut for
228 L<MooseX::Types::Moose>.
230 =head2 Generator methods you can overload
234 =item type_export_generator( $short, $full )
236 Creates a closure returning the type's L<Moose::Meta::TypeConstraint>
239 =item check_export_generator( $short, $full, $undef_message )
241 This creates the closure used to test if a value is valid for this type.
243 =item coercion_export_generator( $short, $full, $undef_message )
245 This is the closure that's doing coercions.
249 =head2 Provided Parameters
255 The short, exported name of the type.
259 The fully qualified name of this type as L<Moose> knows it.
263 A message that will be thrown when type functionality is used but the
264 type does not yet exist.
266 =head1 NOTES REGARDING TYPE UNIONS
268 L<MooseX::Types> uses L<MooseX::Types::TypeDecorator> to do some overloading
269 which generally allows you to easily create union types:
271 subtype StrOrArrayRef,
274 As with parameterized constrains, this overloading extends to modules using the
275 types you define in a type library.
278 use MooseX::Types::Moose qw(HashRef Int);
280 has 'attr' => (isa=>HashRef|Int);
282 And everything should just work as you'd think.
288 Installs the L<MooseX::Types::Base> class into the caller and
289 exports types according to the specification described in
290 L</"LIBRARY DEFINITION">. This will continue to
291 L<Moose::Util::TypeConstraints>' C<import> method to export helper
292 functions you will need to declare your types.
297 my ($class, %args) = @_;
300 # everyone should want this
304 # inject base class into new library
306 unshift @{ $callee . '::ISA' }, 'MooseX::Types::Base';
309 # generate predeclared type helpers
310 if (my @orig_declare = @{ $args{ -declare } || [] }) {
311 my ($tags, $declare) = filter_tags @orig_declare;
314 for my $type (@$declare) {
316 croak "Cannot create a type containing '::' ($type) at the moment"
319 # add type to library and remember to export
320 $callee->add_type($type);
321 push @to_export, $type;
324 $callee->import({ -full => 1, -into => $callee }, @to_export);
327 # run type constraints import
328 return Moose::Util::TypeConstraints->import({ into => $callee });
331 =head2 type_export_generator
333 Generate a type export, e.g. C<Int()>. This will return either a
334 L<Moose::Meta::TypeConstraint> object, or alternatively a
335 L<MooseX::Types::UndefinedType> object if the type was not
340 sub type_export_generator {
341 my ($class, $type, $name) = @_;
343 ## Return an anonymous subroutine that will generate the proxied type
344 ## constraint for you.
348 if(defined(my $params = shift @_)) {
349 ## We currently only allow a TC to accept a single, ArrayRef
350 ## parameter, as in HashRef[Int], where [Int] is what's inside the
352 if(ref $params eq 'ARRAY') {
353 $type_constraint = $class->create_arged_type_constraint($name, @$params);
355 croak 'Arguments must be an ArrayRef, not '. ref $params;
358 $type_constraint = $class->create_base_type_constraint($name);
361 $type_constraint = defined($type_constraint) ? $type_constraint
362 : MooseX::Types::UndefinedType->new($name);
364 my $type_decorator = $class->create_type_decorator($type_constraint);
366 ## If there are additional args, that means it's probably stuff that
367 ## needs to be returned to the subtype. Not an ideal solution here but
368 ## doesn't seem to cause trouble.
371 return ($type_decorator, @_);
373 return $type_decorator;
378 =head2 create_arged_type_constraint ($name, @args)
380 Given a String $name with @args find the matching typeconstraint and parameterize
385 sub create_arged_type_constraint {
386 my ($class, $name, @args) = @_;
387 my $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint("$name");
388 return $type_constraint->parameterize(@args);
391 =head2 create_base_type_constraint ($name)
393 Given a String $name, find the matching typeconstraint.
397 sub create_base_type_constraint {
398 my ($class, $name) = @_;
399 return find_type_constraint($name);
402 =head2 create_type_decorator ($type_constraint)
404 Given a $type_constraint, return a lightweight L<MooseX::Types::TypeDecorator>
409 sub create_type_decorator {
410 my ($class, $type_constraint) = @_;
411 return MooseX::Types::TypeDecorator->new($type_constraint);
414 =head2 coercion_export_generator
416 This generates a coercion handler function, e.g. C<to_Int($value)>.
420 sub coercion_export_generator {
421 my ($class, $type, $full, $undef_msg) = @_;
425 # we need a type object
426 my $tobj = find_type_constraint($full) or croak $undef_msg;
427 my $return = $tobj->coerce($value);
429 # non-successful coercion returns false
430 return unless $tobj->check($return);
436 =head2 check_export_generator
438 Generates a constraint check closure, e.g. C<is_Int($value)>.
442 sub check_export_generator {
443 my ($class, $type, $full, $undef_msg) = @_;
447 # we need a type object
448 my $tobj = find_type_constraint($full) or croak $undef_msg;
450 return $tobj->check($value);
456 The following are lists of gotcha's and their workarounds for developers coming
457 from the standard string based type constraint names
461 A library makes the types quasi-unique by prefixing their names with (by
462 default) the library package name. If you're only using the type handler
463 functions provided by MooseX::Types, you shouldn't ever have to use
464 a type's actual full name.
466 =head2 Argument separation ('=>' versus ',')
468 The Perlop manpage has this to say about the '=>' operator: "The => operator is
469 a synonym for the comma, but forces any word (consisting entirely of word
470 characters) to its left to be interpreted as a string (as of 5.001). This
471 includes words that might otherwise be considered a constant or function call."
473 Due to this stringification, the following will NOT work as you might think:
475 subtype StrOrArrayRef => as Str|ArrayRef;
477 The 'StrOrArrayRef' will have it's stringification activated this causes the
478 subtype to not be created. Since the bareword type constraints are not strings
479 you really should not try to treat them that way. You will have to use the ','
480 operator instead. The author's of this package realize that all the L<Moose>
481 documention and examples nearly uniformly use the '=>' version of the comma
482 operator and this could be an issue if you are converting code.
484 Patches welcome for discussion.
489 L<Moose::Util::TypeConstraints>,
490 L<MooseX::Types::Moose>,
493 =head1 AUTHOR AND COPYRIGHT
495 Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to
496 the C<#moose> cabal on C<irc.perl.org>.
498 Additional features by John Napiorkowski (jnapiorkowski) <jjnapiork@cpan.org>.
502 This program is free software; you can redistribute it and/or modify
503 it under the same terms as perl itself.