1MooseX::Types(3) User Contributed Perl Documentation MooseX::Types(3)
2
6 MooseX::Types - Organise your Moose types in libraries
7
9 Library Definition
10 package MyLibrary;
11 # predeclare our own types
13 use MooseX::Types
14 -declare => [qw(
15 PositiveInt NegativeInt
16 ArrayRefOfPositiveInt ArrayRefOfAtLeastThreeNegativeInts
17 LotsOfInnerConstraints StrOrArrayRef
18 MyDateTime
19 )];
20 # import builtin types
22 use MooseX::Types::Moose qw/Int HashRef/;
23 # type definition.
25 subtype PositiveInt,
26 as Int,
27 where { $_ > 0 },
28 message { "Int is not larger than 0" };
29 subtype NegativeInt,
31 as Int,
32 where { $_ < 0 },
33 message { "Int is not smaller than 0" };
34 # type coercion
36 coerce PositiveInt,
37 from Int,
38 via { 1 };
39 # with parameterized constraints.
41 subtype ArrayRefOfPositiveInt,
43 as ArrayRef[PositiveInt];
44 subtype ArrayRefOfAtLeastThreeNegativeInts,
46 as ArrayRef[NegativeInt],
47 where { scalar(@$_) > 2 };
48 subtype LotsOfInnerConstraints,
50 as ArrayRef[ArrayRef[HashRef[Int]]];
51 # with TypeConstraint Unions
53 subtype StrOrArrayRef,
55 as Str|ArrayRef;
56 # class types
58 class_type 'DateTime';
60 # or better
62 class_type MyDateTime, { class => 'DateTime' };
64 coerce MyDateTime,
66 from HashRef,
67 via { DateTime->new(%$_) };
68 1;
70 Usage
72 package Foo;
73 use Moose;
74 use MyLibrary qw( PositiveInt NegativeInt );
75 # use the exported constants as type names
77 has 'bar',
78 isa => PositiveInt,
79 is => 'rw';
80 has 'baz',
81 isa => NegativeInt,
82 is => 'rw';
83 sub quux {
85 my ($self, $value);
86 # test the value
88 print "positive\n" if is_PositiveInt($value);
89 print "negative\n" if is_NegativeInt($value);
90 # coerce the value, NegativeInt doesn't have a coercion
92 # helper, since it didn't define any coercions.
93 $value = to_PositiveInt($value) or die "Cannot coerce";
94 }
95 1;
97
99 The types provided with Moose are by design global. This package helps
100 you to organise and selectively import your own and the built-in types
101 in libraries. As a nice side effect, it catches typos at compile-time
102 too.
103 However, the main reason for this module is to provide an easy way to
105 not have conflicts with your type names, since the internal fully
106 qualified names of the types will be prefixed with the library's name.
107 This module will also provide you with some helper functions to make it
109 easier to use Moose types in your code.
110 String type names will produce a warning, unless it's for a
112 "class_type" or "role_type" declared within the library, or a fully
113 qualified name like 'MyTypeLibrary::Foo'.
114
116 $type
117 A constant with the name of your type. It contains the type's fully
118 qualified name. Takes no value, as all constants.
119 is_$type
121 This handler takes a value and tests if it is a valid value for this
122 $type. It will return true or false.
123 to_$type
125 A handler that will take a value and coerce it into the $type. It will
126 return a false value if the type could not be coerced.
127 Important Note: This handler will only be exported for types that can
129 do type coercion. This has the advantage that a coercion to a type that
130 cannot hasn't defined any coercions will lead to a compile-time error.
131
133 A MooseX::Types is just a normal Perl module. Unlike Moose itself, it
134 does not install "use strict" and "use warnings" in your class by
135 default, so this is up to you.
136 The only thing a library is required to do is
138 use MooseX::Types -declare => \@types;
140 with @types being a list of types you wish to define in this library.
142 This line will install a proper base class in your package as well as
143 the full set of handlers for your declared types. It will then hand
144 control over to Moose::Util::TypeConstraints' "import" method to export
145 the functions you will need to declare your types.
146 If you want to use Moose' built-in types (e.g. for subtyping) you will
148 want to
149 use MooseX::Types::Moose @types;
151 to import the helpers from the shipped MooseX::Types::Moose library
153 which can export all types that come with Moose.
154 You will have to define coercions for your types or your library won't
156 export a "to_$type" coercion helper for it.
157 Note that you currently cannot define types containing "::", since
159 exporting would be a problem.
160 You also don't need to use "warnings" and "strict", since the
162 definition of a library automatically exports those.
163
165 You can import the "type helpers" of a library by "use"ing it with a
166 list of types to import as arguments. If you want all of them, use the
167 ":all" tag. For example:
168 use MyLibrary ':all';
170 use MyOtherLibrary qw( TypeA TypeB );
171 MooseX::Types comes with a library of Moose' built-in types called
173 MooseX::Types::Moose.
174 The exporting mechanism is, since version 0.5, implemented via a
176 wrapper around Sub::Exporter. This means you can do something like
177 this:
178 use MyLibrary TypeA => { -as => 'MyTypeA' },
180 TypeB => { -as => 'MyTypeB' };
181
183 You can define your own wrapper subclasses to manipulate the behaviour
184 of a set of library exports. Here is an example:
185 package MyWrapper;
187 use strict;
188 use MRO::Compat;
189 use base 'MooseX::Types::Wrapper';
190 sub coercion_export_generator {
192 my $class = shift;
193 my $code = $class->next::method(@_);
194 return sub {
195 my $value = $code->(@_);
196 warn "Coercion returned undef!"
197 unless defined $value;
198 return $value;
199 };
200 }
201 1;
203 This class wraps the coercion generator (e.g., "to_Int()") and warns if
205 a coercion returned an undefined value. You can wrap any library with
206 this:
207 package Foo;
209 use strict;
210 use MyWrapper MyLibrary => [qw( Foo Bar )],
211 Moose => [qw( Str Int )];
212 ...
214 1;
215 The "Moose" library name is a special shortcut for
217 MooseX::Types::Moose.
218 Generator methods you can overload
220 type_export_generator( $short, $full )
221 Creates a closure returning the type's Moose::Meta::TypeConstraint
222 object.
223 check_export_generator( $short, $full, $undef_message )
225 This creates the closure used to test if a value is valid for this
226 type.
227 coercion_export_generator( $short, $full, $undef_message )
229 This is the closure that's doing coercions.
230 Provided Parameters
232 $short
233 The short, exported name of the type.
234 $full
236 The fully qualified name of this type as Moose knows it.
237 $undef_message
239 A message that will be thrown when type functionality is used but
240 the type does not yet exist.
241
243 As of version 0.08, Moose::Types has experimental support for Recursive
244 subtypes. This will allow:
245 subtype Tree() => as HashRef[Str|Tree];
247 Which validates things like:
249 {key=>'value'};
251 {key=>{subkey1=>'value', subkey2=>'value'}}
252 And so on. This feature is new and there may be lurking bugs so don't
254 be afraid to hunt me down with patches and test cases if you have
255 trouble.
256
258 MooseX::Types uses MooseX::Types::TypeDecorator to do some overloading
259 which generally allows you to easily create union types:
260 subtype StrOrArrayRef,
262 as Str|ArrayRef;
263 As with parameterized constrains, this overloading extends to modules
265 using the types you define in a type library.
266 use Moose;
268 use MooseX::Types::Moose qw(HashRef Int);
269 has 'attr' => (isa=>HashRef|Int);
271 And everything should just work as you'd think.
273
275 import
276 Installs the MooseX::Types::Base class into the caller and exports
277 types according to the specification described in "LIBRARY DEFINITION".
278 This will continue to Moose::Util::TypeConstraints' "import" method to
279 export helper functions you will need to declare your types.
280 type_export_generator
282 Generate a type export, e.g. "Int()". This will return either a
283 Moose::Meta::TypeConstraint object, or alternatively a
284 MooseX::Types::UndefinedType object if the type was not yet defined.
285 create_arged_type_constraint ($name, @args)
287 Given a String $name with @args find the matching typeconstraint and
288 parameterize it with @args.
289 create_base_type_constraint ($name)
291 Given a String $name, find the matching typeconstraint.
292 create_type_decorator ($type_constraint)
294 Given a $type_constraint, return a lightweight
295 MooseX::Types::TypeDecorator instance.
296 coercion_export_generator
298 This generates a coercion handler function, e.g. "to_Int($value)".
299 check_export_generator
301 Generates a constraint check closure, e.g. "is_Int($value)".
302
304 The following are lists of gotcha's and their workarounds for
305 developers coming from the standard string based type constraint names
306 Uniqueness
308 A library makes the types quasi-unique by prefixing their names with
309 (by default) the library package name. If you're only using the type
310 handler functions provided by MooseX::Types, you shouldn't ever have to
311 use a type's actual full name.
312 Argument separation ('=>' versus ',')
314 The Perlop manpage has this to say about the '=>' operator: "The =>
315 operator is a synonym for the comma, but forces any word (consisting
316 entirely of word characters) to its left to be interpreted as a string
317 (as of 5.001). This includes words that might otherwise be considered a
318 constant or function call."
319 Due to this stringification, the following will NOT work as you might
321 think:
322 subtype StrOrArrayRef => as Str|ArrayRef;
324 The 'StrOrArrayRef' will have it's stringification activated this
326 causes the subtype to not be created. Since the bareword type
327 constraints are not strings you really should not try to treat them
328 that way. You will have to use the ',' operator instead. The author's
329 of this package realize that all the Moose documention and examples
330 nearly uniformly use the '=>' version of the comma operator and this
331 could be an issue if you are converting code.
332 Patches welcome for discussion.
334 Compatibility with Sub::Exporter
336 If you want to use Sub::Exporter with a Type Library, you need to make
337 sure you export all the type constraints declared AS WELL AS any
338 additional export targets. For example if you do:
339 package TypeAndSubExporter; {
341 use MooseX::Types::Moose qw(Str);
343 use MooseX::Types -declare => [qw(MyStr)];
344 use Sub::Exporter -setup => { exports => [ qw(something) ] };
345 subtype MyStr,
347 as Str;
348 sub something {
350 return 1;
351 }
352 } 1;
354 package Foo; {
356 use TypeAndSubExporter qw(MyStr);
357 } 1;
358 You'll get a '"MyStr" is not exported by the TypeAndSubExporter module'
360 error. Upi can workaround by:
361 - use Sub::Exporter -setup => { exports => [ qw(something) ] };
363 + use Sub::Exporter -setup => { exports => [ qw(something MyStr) ] };
364 This is a workaround and I am exploring how to make these modules work
366 better together. I realize this workaround will lead a lot of
367 duplication in your export declarations and will be onerous for large
368 type libraries. Patches and detailed test cases welcome. See the tests
369 directory for a start on this.
370
372 Moose, Moose::Util::TypeConstraints, MooseX::Types::Moose,
373 Sub::Exporter
374
376 Many thanks to the "#moose" cabal on "irc.perl.org".
377
379 Robert "phaylon" Sedlacek <rs@474.at>
380
382 jnapiorkowski: John Napiorkowski <jjnapiork@cpan.org>
383 caelum: Rafael Kitover <rkitover@cpan.org>
385 rafl: Florian Ragwitz <rafl@debian.org>
387 hdp: Hans Dieter Pearcey <hdp@cpan.org>
389 autarch: Dave Rolsky <autarch@urth.org>
391
393 Copyright (c) 2007-2009 Robert Sedlacek <rs@474.at>
394 This program is free software; you can redistribute it and/or modify it
396 under the same terms as perl itself.
397perl v5.12.1 2010-06-01 MooseX::Types(3)