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1 | package MooseX::Types; |
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2 | use Moose; |
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3 | |
4 | =head1 NAME |
5 | |
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6 | MooseX::Types - Organise your Moose types in libraries |
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7 | |
8 | =cut |
9 | |
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10 | #use warnings; |
11 | #use strict; |
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12 | |
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13 | use Moose::Util::TypeConstraints; |
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14 | use MooseX::Types::TypeDecorator; |
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15 | use MooseX::Types::Base (); |
16 | use MooseX::Types::Util qw( filter_tags ); |
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17 | use MooseX::Types::UndefinedType; |
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18 | use Carp::Clan qw( ^MooseX::Types ); |
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19 | |
20 | use namespace::clean -except => [qw( meta )]; |
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21 | |
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22 | our $VERSION = 0.07; |
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23 | my $UndefMsg = q{Action for type '%s' not yet defined in library '%s'}; |
24 | |
25 | =head1 SYNOPSIS |
26 | |
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27 | =head2 Library Definition |
28 | |
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29 | package MyLibrary; |
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30 | |
31 | # predeclare our own types |
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32 | use MooseX::Types |
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33 | -declare => [qw( |
34 | PositiveInt NegativeInt |
35 | ArrayRefOfPositiveInt ArrayRefOfAtLeastThreeNegativeInts |
36 | LotsOfInnerConstraints StrOrArrayRef |
37 | )]; |
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38 | |
39 | # import builtin types |
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40 | use MooseX::Types::Moose 'Int'; |
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41 | |
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42 | # type definition. |
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43 | subtype PositiveInt, |
44 | as Int, |
45 | where { $_ > 0 }, |
46 | message { "Int is not larger than 0" }; |
47 | |
48 | subtype NegativeInt, |
49 | as Int, |
50 | where { $_ < 0 }, |
51 | message { "Int is not smaller than 0" }; |
52 | |
53 | # type coercion |
54 | coerce PositiveInt, |
55 | from Int, |
56 | via { 1 }; |
57 | |
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58 | # with parameterized constraints. |
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59 | |
60 | subtype ArrayRefOfPositiveInt, |
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61 | as ArrayRef[PositiveInt]; |
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62 | |
63 | subtype ArrayRefOfAtLeastThreeNegativeInts, |
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64 | as ArrayRef[NegativeInt], |
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65 | where { scalar(@$_) > 2 }; |
66 | |
67 | subtype LotsOfInnerConstraints, |
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68 | as ArrayRef[ArrayRef[HashRef[Int]]]; |
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69 | |
70 | # with TypeConstraint Unions |
71 | |
72 | subtype StrOrArrayRef, |
73 | as Str|ArrayRef; |
74 | |
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75 | 1; |
76 | |
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77 | =head2 Usage |
78 | |
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79 | package Foo; |
80 | use Moose; |
81 | use MyLibrary qw( PositiveInt NegativeInt ); |
82 | |
83 | # use the exported constants as type names |
84 | has 'bar', |
85 | isa => PositiveInt, |
86 | is => 'rw'; |
87 | has 'baz', |
88 | isa => NegativeInt, |
89 | is => 'rw'; |
90 | |
91 | sub quux { |
92 | my ($self, $value); |
93 | |
94 | # test the value |
95 | print "positive\n" if is_PositiveInt($value); |
96 | print "negative\n" if is_NegativeInt($value); |
97 | |
98 | # coerce the value, NegativeInt doesn't have a coercion |
99 | # helper, since it didn't define any coercions. |
100 | $value = to_PositiveInt($value) or die "Cannot coerce"; |
101 | } |
102 | |
103 | 1; |
104 | |
105 | =head1 DESCRIPTION |
106 | |
107 | The types provided with L<Moose> are by design global. This package helps |
108 | you to organise and selectively import your own and the built-in types in |
109 | libraries. As a nice side effect, it catches typos at compile-time too. |
110 | |
111 | However, the main reason for this module is to provide an easy way to not |
112 | have conflicts with your type names, since the internal fully qualified |
113 | names of the types will be prefixed with the library's name. |
114 | |
115 | This module will also provide you with some helper functions to make it |
116 | easier to use Moose types in your code. |
117 | |
118 | =head1 TYPE HANDLER FUNCTIONS |
119 | |
120 | =head2 $type |
121 | |
122 | A constant with the name of your type. It contains the type's fully |
123 | qualified name. Takes no value, as all constants. |
124 | |
125 | =head2 is_$type |
126 | |
127 | This handler takes a value and tests if it is a valid value for this |
128 | C<$type>. It will return true or false. |
129 | |
130 | =head2 to_$type |
131 | |
132 | A handler that will take a value and coerce it into the C<$type>. It will |
133 | return a false value if the type could not be coerced. |
134 | |
135 | B<Important Note>: This handler will only be exported for types that can |
136 | do type coercion. This has the advantage that a coercion to a type that |
137 | cannot hasn't defined any coercions will lead to a compile-time error. |
138 | |
139 | =head1 LIBRARY DEFINITION |
140 | |
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141 | A MooseX::Types is just a normal Perl module. Unlike Moose |
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142 | itself, it does not install C<use strict> and C<use warnings> in your |
143 | class by default, so this is up to you. |
144 | |
145 | The only thing a library is required to do is |
146 | |
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147 | use MooseX::Types -declare => \@types; |
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148 | |
149 | with C<@types> being a list of types you wish to define in this library. |
150 | This line will install a proper base class in your package as well as the |
151 | full set of L<handlers|/"TYPE HANDLER FUNCTIONS"> for your declared |
152 | types. It will then hand control over to L<Moose::Util::TypeConstraints>' |
153 | C<import> method to export the functions you will need to declare your |
154 | types. |
155 | |
156 | If you want to use Moose' built-in types (e.g. for subtyping) you will |
157 | want to |
158 | |
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159 | use MooseX::Types::Moose @types; |
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160 | |
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161 | to import the helpers from the shipped L<MooseX::Types::Moose> |
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162 | library which can export all types that come with Moose. |
163 | |
164 | You will have to define coercions for your types or your library won't |
165 | export a L</to_$type> coercion helper for it. |
166 | |
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167 | Note that you currently cannot define types containing C<::>, since |
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168 | exporting would be a problem. |
169 | |
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170 | You also don't need to use C<warnings> and C<strict>, since the |
171 | definition of a library automatically exports those. |
172 | |
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173 | =head1 LIBRARY USAGE |
174 | |
175 | You can import the L<"type helpers"|/"TYPE HANDLER FUNCTIONS"> of a |
176 | library by C<use>ing it with a list of types to import as arguments. If |
177 | you want all of them, use the C<:all> tag. For example: |
178 | |
179 | use MyLibrary ':all'; |
180 | use MyOtherLibrary qw( TypeA TypeB ); |
181 | |
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182 | MooseX::Types comes with a library of Moose' built-in types called |
183 | L<MooseX::Types::Moose>. |
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184 | |
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185 | The exporting mechanism is, since version 0.5, implemented via a wrapper |
186 | around L<Sub::Exporter>. This means you can do something like this: |
187 | |
188 | use MyLibrary TypeA => { -as => 'MyTypeA' }, |
189 | TypeB => { -as => 'MyTypeB' }; |
190 | |
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191 | =head1 WRAPPING A LIBRARY |
192 | |
193 | You can define your own wrapper subclasses to manipulate the behaviour |
194 | of a set of library exports. Here is an example: |
195 | |
196 | package MyWrapper; |
197 | use strict; |
198 | use Class::C3; |
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199 | use base 'MooseX::Types::Wrapper'; |
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200 | |
201 | sub coercion_export_generator { |
202 | my $class = shift; |
203 | my $code = $class->next::method(@_); |
204 | return sub { |
205 | my $value = $code->(@_); |
206 | warn "Coercion returned undef!" |
207 | unless defined $value; |
208 | return $value; |
209 | }; |
210 | } |
211 | |
212 | 1; |
213 | |
214 | This class wraps the coercion generator (e.g., C<to_Int()>) and warns |
215 | if a coercion returned an undefined value. You can wrap any library |
216 | with this: |
217 | |
218 | package Foo; |
219 | use strict; |
220 | use MyWrapper MyLibrary => [qw( Foo Bar )], |
221 | Moose => [qw( Str Int )]; |
222 | |
223 | ... |
224 | 1; |
225 | |
226 | The C<Moose> library name is a special shortcut for |
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227 | L<MooseX::Types::Moose>. |
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228 | |
229 | =head2 Generator methods you can overload |
230 | |
231 | =over 4 |
232 | |
233 | =item type_export_generator( $short, $full ) |
234 | |
235 | Creates a closure returning the type's L<Moose::Meta::TypeConstraint> |
236 | object. |
237 | |
238 | =item check_export_generator( $short, $full, $undef_message ) |
239 | |
240 | This creates the closure used to test if a value is valid for this type. |
241 | |
242 | =item coercion_export_generator( $short, $full, $undef_message ) |
243 | |
244 | This is the closure that's doing coercions. |
245 | |
246 | =back |
247 | |
248 | =head2 Provided Parameters |
249 | |
250 | =over 4 |
251 | |
252 | =item $short |
253 | |
254 | The short, exported name of the type. |
255 | |
256 | =item $full |
257 | |
258 | The fully qualified name of this type as L<Moose> knows it. |
259 | |
260 | =item $undef_message |
261 | |
262 | A message that will be thrown when type functionality is used but the |
263 | type does not yet exist. |
264 | |
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265 | =head1 NOTES REGARDING TYPE UNIONS |
266 | |
267 | L<MooseX::Types> uses L<MooseX::Types::TypeDecorator> to do some overloading |
268 | which generally allows you to easily create union types: |
269 | |
270 | subtype StrOrArrayRef, |
271 | as Str|ArrayRef; |
272 | |
273 | As with parameterized constrains, this overloading extends to modules using the |
274 | types you define in a type library. |
275 | |
276 | use Moose; |
277 | use MooseX::Types::Moose qw(HashRef Int); |
278 | |
279 | has 'attr' => (isa=>HashRef|Int); |
280 | |
281 | And everything should just work as you'd think. |
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282 | |
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283 | =head1 METHODS |
284 | |
285 | =head2 import |
286 | |
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287 | Installs the L<MooseX::Types::Base> class into the caller and |
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288 | exports types according to the specification described in |
289 | L</"LIBRARY DEFINITION">. This will continue to |
290 | L<Moose::Util::TypeConstraints>' C<import> method to export helper |
291 | functions you will need to declare your types. |
292 | |
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293 | =cut |
294 | |
295 | sub import { |
296 | my ($class, %args) = @_; |
297 | my $callee = caller; |
298 | |
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299 | # everyone should want this |
300 | strict->import; |
301 | warnings->import; |
302 | |
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303 | # inject base class into new library |
304 | { no strict 'refs'; |
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305 | unshift @{ $callee . '::ISA' }, 'MooseX::Types::Base'; |
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306 | } |
307 | |
308 | # generate predeclared type helpers |
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309 | if (my @orig_declare = @{ $args{ -declare } || [] }) { |
310 | my ($tags, $declare) = filter_tags @orig_declare; |
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311 | my @to_export; |
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312 | |
313 | for my $type (@$declare) { |
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314 | |
315 | croak "Cannot create a type containing '::' ($type) at the moment" |
316 | if $type =~ /::/; |
317 | |
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318 | # add type to library and remember to export |
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319 | $callee->add_type($type); |
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320 | push @to_export, $type; |
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321 | } |
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322 | |
323 | $callee->import({ -full => 1, -into => $callee }, @to_export); |
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324 | } |
325 | |
326 | # run type constraints import |
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327 | return Moose::Util::TypeConstraints->import({ into => $callee }); |
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328 | } |
329 | |
330 | =head2 type_export_generator |
331 | |
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332 | Generate a type export, e.g. C<Int()>. This will return either a |
333 | L<Moose::Meta::TypeConstraint> object, or alternatively a |
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334 | L<MooseX::Types::UndefinedType> object if the type was not |
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335 | yet defined. |
336 | |
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337 | =cut |
338 | |
339 | sub type_export_generator { |
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340 | my ($class, $type, $name) = @_; |
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341 | |
342 | ## Return an anonymous subroutine that will generate the proxied type |
343 | ## constraint for you. |
344 | |
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345 | return sub { |
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346 | my $type_constraint; |
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347 | if(defined(my $params = shift @_)) { |
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348 | ## We currently only allow a TC to accept a single, ArrayRef |
349 | ## parameter, as in HashRef[Int], where [Int] is what's inside the |
350 | ## ArrayRef passed. |
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351 | if(ref $params eq 'ARRAY') { |
352 | $type_constraint = $class->create_arged_type_constraint($name, @$params); |
353 | } else { |
354 | croak 'Arguments must be an ArrayRef, not '. ref $params; |
355 | } |
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356 | } else { |
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357 | $type_constraint = $class->create_base_type_constraint($name); |
358 | } |
359 | $type_constraint = defined($type_constraint) ? $type_constraint |
360 | : MooseX::Types::UndefinedType->new($name); |
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361 | |
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362 | my $type_decorator = $class->create_type_decorator($type_constraint); |
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363 | |
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364 | ## If there are additional args, that means it's probably stuff that |
365 | ## needs to be returned to the subtype. Not an ideal solution here but |
366 | ## doesn't seem to cause trouble. |
367 | |
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368 | if(@_) { |
369 | return ($type_decorator, @_); |
370 | } else { |
371 | return $type_decorator; |
372 | } |
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373 | }; |
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374 | } |
375 | |
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376 | =head2 create_arged_type_constraint ($name, @args) |
377 | |
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378 | Given a String $name with @args find the matching typeconstraint and parameterize |
379 | it with @args. |
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380 | |
381 | =cut |
382 | |
383 | sub create_arged_type_constraint { |
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384 | my ($class, $name, @args) = @_; |
385 | my $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint("$name"); |
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386 | return $type_constraint->parameterize(@args); |
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387 | } |
388 | |
389 | =head2 create_base_type_constraint ($name) |
390 | |
391 | Given a String $name, find the matching typeconstraint. |
392 | |
393 | =cut |
394 | |
395 | sub create_base_type_constraint { |
396 | my ($class, $name) = @_; |
397 | return find_type_constraint($name); |
398 | } |
399 | |
400 | =head2 create_type_decorator ($type_constraint) |
401 | |
402 | Given a $type_constraint, return a lightweight L<MooseX::Types::TypeDecorator> |
403 | instance. |
404 | |
405 | =cut |
406 | |
407 | sub create_type_decorator { |
408 | my ($class, $type_constraint) = @_; |
475bbd1d |
409 | return MooseX::Types::TypeDecorator->new($type_constraint); |
a706b0f2 |
410 | } |
411 | |
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412 | =head2 coercion_export_generator |
413 | |
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414 | This generates a coercion handler function, e.g. C<to_Int($value)>. |
415 | |
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416 | =cut |
417 | |
418 | sub coercion_export_generator { |
419 | my ($class, $type, $full, $undef_msg) = @_; |
420 | return sub { |
421 | my ($value) = @_; |
422 | |
423 | # we need a type object |
424 | my $tobj = find_type_constraint($full) or croak $undef_msg; |
425 | my $return = $tobj->coerce($value); |
426 | |
427 | # non-successful coercion returns false |
428 | return unless $tobj->check($return); |
429 | |
430 | return $return; |
431 | } |
432 | } |
433 | |
434 | =head2 check_export_generator |
435 | |
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436 | Generates a constraint check closure, e.g. C<is_Int($value)>. |
437 | |
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438 | =cut |
439 | |
440 | sub check_export_generator { |
441 | my ($class, $type, $full, $undef_msg) = @_; |
442 | return sub { |
443 | my ($value) = @_; |
444 | |
445 | # we need a type object |
446 | my $tobj = find_type_constraint($full) or croak $undef_msg; |
447 | |
448 | return $tobj->check($value); |
449 | } |
450 | } |
451 | |
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452 | =head1 CAVEATS |
453 | |
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454 | The following are lists of gotcha's and their workarounds for developers coming |
455 | from the standard string based type constraint names |
456 | |
457 | =head2 Uniqueness |
458 | |
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459 | A library makes the types quasi-unique by prefixing their names with (by |
460 | default) the library package name. If you're only using the type handler |
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461 | functions provided by MooseX::Types, you shouldn't ever have to use |
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462 | a type's actual full name. |
463 | |
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464 | =head2 Argument separation ('=>' versus ',') |
465 | |
466 | The Perlop manpage has this to say about the '=>' operator: "The => operator is |
467 | a synonym for the comma, but forces any word (consisting entirely of word |
468 | characters) to its left to be interpreted as a string (as of 5.001). This |
469 | includes words that might otherwise be considered a constant or function call." |
470 | |
471 | Due to this stringification, the following will NOT work as you might think: |
472 | |
473 | subtype StrOrArrayRef => as Str|ArrayRef; |
474 | |
475 | The 'StrOrArrayRef' will have it's stringification activated this causes the |
476 | subtype to not be created. Since the bareword type constraints are not strings |
477 | you really should not try to treat them that way. You will have to use the ',' |
478 | operator instead. The author's of this package realize that all the L<Moose> |
479 | documention and examples nearly uniformly use the '=>' version of the comma |
480 | operator and this could be an issue if you are converting code. |
481 | |
482 | Patches welcome for discussion. |
483 | |
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484 | =head1 SEE ALSO |
485 | |
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486 | L<Moose>, |
487 | L<Moose::Util::TypeConstraints>, |
488 | L<MooseX::Types::Moose>, |
489 | L<Sub::Exporter> |
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490 | |
491 | =head1 AUTHOR AND COPYRIGHT |
492 | |
493 | Robert 'phaylon' Sedlacek C<E<lt>rs@474.atE<gt>>, with many thanks to |
494 | the C<#moose> cabal on C<irc.perl.org>. |
495 | |
475bbd1d |
496 | Additional features by John Napiorkowski (jnapiorkowski) <jjnapiork@cpan.org>. |
497 | |
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498 | =head1 LICENSE |
499 | |
500 | This program is free software; you can redistribute it and/or modify |
501 | it under the same terms as perl itself. |
502 | |
503 | =cut |
504 | |
505 | 1; |