Commit | Line | Data |
c0e30cf5 |
1 | |
2 | package Moose::Meta::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
78cd1d3b |
7 | use Scalar::Util 'blessed', 'weaken', 'reftype'; |
a15dff8d |
8 | use Carp 'confess'; |
7dbbdcab |
9 | use Sub::Name 'subname'; |
a909a4df |
10 | use overload (); |
a15dff8d |
11 | |
80d955e4 |
12 | our $VERSION = '0.22'; |
d44714be |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
78cd1d3b |
14 | |
8ee73eeb |
15 | use Moose::Meta::Method::Accessor; |
a3c7e2fe |
16 | use Moose::Util::TypeConstraints (); |
bc1e29b5 |
17 | |
c0e30cf5 |
18 | use base 'Class::MOP::Attribute'; |
19 | |
452bac1b |
20 | # options which are not directly used |
21 | # but we store them for metadata purposes |
98aae381 |
22 | __PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata')); |
23 | __PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata')); |
24 | __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); |
452bac1b |
25 | |
26 | # these are actual options for the attrs |
1a563243 |
27 | __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); |
28 | __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); |
26fbace8 |
29 | __PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' )); |
1a563243 |
30 | __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); |
31 | __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); |
32 | __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); |
82168dbb |
33 | __PACKAGE__->meta->add_attribute('type_constraint' => ( |
34 | reader => 'type_constraint', |
35 | predicate => 'has_type_constraint', |
36 | )); |
8c9d74e7 |
37 | __PACKAGE__->meta->add_attribute('trigger' => ( |
38 | reader => 'trigger', |
39 | predicate => 'has_trigger', |
40 | )); |
452bac1b |
41 | __PACKAGE__->meta->add_attribute('handles' => ( |
42 | reader => 'handles', |
43 | predicate => 'has_handles', |
44 | )); |
ddbdc0cb |
45 | __PACKAGE__->meta->add_attribute('documentation' => ( |
46 | reader => 'documentation', |
47 | predicate => 'has_documentation', |
48 | )); |
82168dbb |
49 | |
587e457d |
50 | # NOTE: |
51 | # we need to have a ->does method in here to |
52 | # more easily support traits, and the introspection |
53 | # of those traits. So in order to do this we |
54 | # just alias Moose::Object's version of it. |
55 | # - SL |
56 | *does = \&Moose::Object::does; |
57 | |
78cd1d3b |
58 | sub new { |
f3c4e20e |
59 | my ($class, $name, %options) = @_; |
60 | $class->_process_options($name, \%options); |
61 | return $class->SUPER::new($name, %options); |
1d768fb1 |
62 | } |
63 | |
ce0e8d63 |
64 | sub clone_and_inherit_options { |
65 | my ($self, %options) = @_; |
83cc9094 |
66 | # you can change default, required, coerce, documentation and lazy |
ce0e8d63 |
67 | my %actual_options; |
83cc9094 |
68 | foreach my $legal_option (qw(default coerce required documentation lazy)) { |
ce0e8d63 |
69 | if (exists $options{$legal_option}) { |
70 | $actual_options{$legal_option} = $options{$legal_option}; |
71 | delete $options{$legal_option}; |
72 | } |
73 | } |
26fbace8 |
74 | |
83cc9094 |
75 | # handles can only be added, not changed |
76 | if ($options{handles}) { |
77 | confess "You can only add the 'handles' option, you cannot change it" |
78 | if $self->has_handles; |
79 | $actual_options{handles} = $options{handles}; |
80 | delete $options{handles}; |
81 | } |
8d62bf6d |
82 | |
83 | # handles can only be added, not changed |
84 | if ($options{builder}) { |
85 | confess "You can only add the 'builder' option, you cannot change it" |
86 | if $self->has_builder; |
87 | $actual_options{builder} = $options{builder}; |
88 | delete $options{builder}; |
89 | } |
26fbace8 |
90 | |
91 | # isa can be changed, but only if the |
92 | # new type is a subtype |
ce0e8d63 |
93 | if ($options{isa}) { |
94 | my $type_constraint; |
8de73ff1 |
95 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
96 | $type_constraint = $options{isa}; |
97 | } |
98 | else { |
99 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
100 | $options{isa} |
101 | ); |
102 | (defined $type_constraint) |
103 | || confess "Could not find the type constraint '" . $options{isa} . "'"; |
104 | } |
105 | # NOTE: |
106 | # check here to see if the new type |
107 | # is a subtype of the old one |
1b58cb9f |
108 | # or if the old one is a union and the |
109 | # subtype (or a supertype of it) is included |
110 | # in the union |
111 | $type_constraint->is_subtype_of($self->type_constraint->name) |
112 | || ($self->type_constraint->can('includes_type') && $self->type_constraint->includes_type($type_constraint)) |
113 | || confess "New type constraint setting must be a subtype of inherited one" . ($self->type_constraint->can('includes_type') ? ", or included in the inherited constraint" : '') |
114 | # iff we have a type constraint that is ... |
115 | if $self->has_type_constraint; |
8de73ff1 |
116 | # then we use it :) |
117 | $actual_options{type_constraint} = $type_constraint; |
ce0e8d63 |
118 | delete $options{isa}; |
119 | } |
26fbace8 |
120 | (scalar keys %options == 0) |
ce0e8d63 |
121 | || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; |
122 | $self->clone(%actual_options); |
1d768fb1 |
123 | } |
124 | |
125 | sub _process_options { |
126 | my ($class, $name, $options) = @_; |
8de73ff1 |
127 | |
f3c4e20e |
128 | if (exists $options->{is}) { |
8de73ff1 |
129 | if ($options->{is} eq 'ro') { |
130 | $options->{reader} ||= $name; |
131 | (!exists $options->{trigger}) |
132 | || confess "Cannot have a trigger on a read-only attribute"; |
133 | } |
134 | elsif ($options->{is} eq 'rw') { |
135 | $options->{accessor} = $name; |
136 | ((reftype($options->{trigger}) || '') eq 'CODE') |
137 | || confess "Trigger must be a CODE ref" |
138 | if exists $options->{trigger}; |
139 | } |
140 | else { |
141 | confess "I do not understand this option (is => " . $options->{is} . ")" |
142 | } |
f3c4e20e |
143 | } |
8de73ff1 |
144 | |
f3c4e20e |
145 | if (exists $options->{isa}) { |
f3c4e20e |
146 | if (exists $options->{does}) { |
147 | if (eval { $options->{isa}->can('does') }) { |
148 | ($options->{isa}->does($options->{does})) |
149 | || confess "Cannot have an isa option and a does option if the isa does not do the does"; |
150 | } |
151 | else { |
152 | confess "Cannot have an isa option which cannot ->does()"; |
26fbace8 |
153 | } |
26fbace8 |
154 | } |
8de73ff1 |
155 | |
f3c4e20e |
156 | # allow for anon-subtypes here ... |
157 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
8de73ff1 |
158 | $options->{type_constraint} = $options->{isa}; |
159 | } |
160 | else { |
161 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
162 | $options->{isa} => { |
f3c4e20e |
163 | parent => Moose::Util::TypeConstraints::find_type_constraint('Object'), |
164 | constraint => sub { $_[0]->isa($options->{isa}) } |
26fbace8 |
165 | } |
8de73ff1 |
166 | ); |
167 | } |
f3c4e20e |
168 | } |
169 | elsif (exists $options->{does}) { |
170 | # allow for anon-subtypes here ... |
171 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
238b424d |
172 | $options->{type_constraint} = $options->{does}; |
8de73ff1 |
173 | } |
174 | else { |
175 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
176 | $options->{does} => { |
f3c4e20e |
177 | parent => Moose::Util::TypeConstraints::find_type_constraint('Role'), |
238b424d |
178 | constraint => sub { |
179 | Moose::Util::does_role($_[0], $options->{does}) |
180 | } |
26fbace8 |
181 | } |
8de73ff1 |
182 | ); |
183 | } |
f3c4e20e |
184 | } |
8de73ff1 |
185 | |
f3c4e20e |
186 | if (exists $options->{coerce} && $options->{coerce}) { |
187 | (exists $options->{type_constraint}) |
188 | || confess "You cannot have coercion without specifying a type constraint"; |
8de73ff1 |
189 | confess "You cannot have a weak reference to a coerced value" |
190 | if $options->{weak_ref}; |
f3c4e20e |
191 | } |
8de73ff1 |
192 | |
f3c4e20e |
193 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
194 | (exists $options->{type_constraint}) |
195 | || confess "You cannot auto-dereference without specifying a type constraint"; |
196 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
8de73ff1 |
197 | $options->{type_constraint}->is_a_type_of('HashRef')) |
f3c4e20e |
198 | || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; |
199 | } |
8de73ff1 |
200 | |
f3c4e20e |
201 | if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { |
202 | confess("You can not use lazy_build and default for the same attribute") |
8de73ff1 |
203 | if exists $options->{default}; |
a6c84c69 |
204 | $options->{lazy} = 1; |
205 | $options->{required} = 1; |
206 | $options->{builder} ||= "_build_${name}"; |
207 | if ($name =~ /^_/) { |
f3c4e20e |
208 | $options->{clearer} ||= "_clear${name}"; |
209 | $options->{predicate} ||= "_has${name}"; |
a6c84c69 |
210 | } |
211 | else { |
f3c4e20e |
212 | $options->{clearer} ||= "clear_${name}"; |
213 | $options->{predicate} ||= "has_${name}"; |
26fbace8 |
214 | } |
f3c4e20e |
215 | } |
8de73ff1 |
216 | |
f3c4e20e |
217 | if (exists $options->{lazy} && $options->{lazy}) { |
9edba990 |
218 | (exists $options->{default} || defined $options->{builder} ) |
f3c4e20e |
219 | || confess "You cannot have lazy attribute without specifying a default value for it"; |
220 | } |
26fbace8 |
221 | |
9edba990 |
222 | if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) { |
223 | confess "You cannot have a required attribute without a default, builder, or an init_arg"; |
224 | } |
225 | |
78cd1d3b |
226 | } |
c0e30cf5 |
227 | |
d500266f |
228 | sub initialize_instance_slot { |
ddd0ec20 |
229 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
230 | my $init_arg = $self->init_arg(); |
231 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
232 | |
26fbace8 |
233 | my $val; |
1ed0b94f |
234 | my $value_is_set; |
625d571f |
235 | if ( defined($init_arg) and exists $params->{$init_arg}) { |
d500266f |
236 | $val = $params->{$init_arg}; |
2c78d811 |
237 | $value_is_set = 1; |
d500266f |
238 | } |
239 | else { |
240 | # skip it if it's lazy |
241 | return if $self->is_lazy; |
242 | # and die if it's required and doesn't have a default value |
26fbace8 |
243 | confess "Attribute (" . $self->name . ") is required" |
244 | if $self->is_required && !$self->has_default && !$self->has_builder; |
ddd0ec20 |
245 | |
1ed0b94f |
246 | # if nothing was in the %params, we can use the |
247 | # attribute's default value (if it has one) |
248 | if ($self->has_default) { |
249 | $val = $self->default($instance); |
250 | $value_is_set = 1; |
a6c84c69 |
251 | } |
252 | elsif ($self->has_builder) { |
253 | if (my $builder = $instance->can($self->builder)){ |
1ed0b94f |
254 | $val = $instance->$builder; |
255 | $value_is_set = 1; |
a6c84c69 |
256 | } |
257 | else { |
0b26305c |
258 | confess(blessed($instance)." does not support builder method '".$self->builder."' for attribute '" . $self->name . "'"); |
1ed0b94f |
259 | } |
a0748c37 |
260 | } |
26fbace8 |
261 | } |
262 | |
1ed0b94f |
263 | return unless $value_is_set; |
264 | |
265 | if ($self->has_type_constraint) { |
266 | my $type_constraint = $self->type_constraint; |
267 | if ($self->should_coerce && $type_constraint->has_coercion) { |
268 | $val = $type_constraint->coerce($val); |
d500266f |
269 | } |
ab76842e |
270 | $type_constraint->check($val) |
688fcdda |
271 | || confess "Attribute (" |
272 | . $self->name |
273 | . ") does not pass the type constraint because: " |
274 | . $type_constraint->get_message($val); |
1ed0b94f |
275 | } |
ddd0ec20 |
276 | |
759e4e8f |
277 | $self->set_initial_value($instance, $val); |
26fbace8 |
278 | $meta_instance->weaken_slot_value($instance, $self->name) |
a6c84c69 |
279 | if ref $val && $self->is_weak_ref; |
d500266f |
280 | } |
281 | |
d617b644 |
282 | ## Slot management |
9e93dd19 |
283 | |
8abe9636 |
284 | # FIXME: |
285 | # this duplicates too much code from |
286 | # Class::MOP::Attribute, we need to |
287 | # refactor these bits eventually. |
288 | # - SL |
289 | sub _set_initial_slot_value { |
290 | my ($self, $meta_instance, $instance, $value) = @_; |
291 | |
292 | my $slot_name = $self->name; |
293 | |
294 | return $meta_instance->set_slot_value($instance, $slot_name, $value) |
295 | unless $self->has_initializer; |
296 | |
297 | my ($type_constraint, $can_coerce); |
298 | if ($self->has_type_constraint) { |
299 | $type_constraint = $self->type_constraint; |
300 | $can_coerce = ($self->should_coerce && $type_constraint->has_coercion); |
301 | } |
302 | |
303 | my $callback = sub { |
304 | my $val = shift; |
305 | if ($type_constraint) { |
306 | $val = $type_constraint->coerce($val) |
307 | if $can_coerce; |
308 | $type_constraint->check($val) |
309 | || confess "Attribute (" |
310 | . $slot_name |
311 | . ") does not pass the type constraint because: " |
312 | . $type_constraint->get_message($val); |
313 | } |
314 | $meta_instance->set_slot_value($instance, $slot_name, $val); |
315 | }; |
316 | |
317 | my $initializer = $self->initializer; |
318 | |
319 | # most things will just want to set a value, so make it first arg |
320 | $instance->$initializer($value, $callback, $self); |
321 | } |
322 | |
946289d1 |
323 | sub set_value { |
324 | my ($self, $instance, $value) = @_; |
26fbace8 |
325 | |
946289d1 |
326 | my $attr_name = $self->name; |
26fbace8 |
327 | |
946289d1 |
328 | if ($self->is_required) { |
26fbace8 |
329 | defined($value) |
946289d1 |
330 | || confess "Attribute ($attr_name) is required, so cannot be set to undef"; |
331 | } |
26fbace8 |
332 | |
946289d1 |
333 | if ($self->has_type_constraint) { |
26fbace8 |
334 | |
946289d1 |
335 | my $type_constraint = $self->type_constraint; |
26fbace8 |
336 | |
946289d1 |
337 | if ($self->should_coerce) { |
26fbace8 |
338 | $value = $type_constraint->coerce($value); |
688fcdda |
339 | } |
42bc21a4 |
340 | $type_constraint->_compiled_type_constraint->($value) |
688fcdda |
341 | || confess "Attribute (" |
342 | . $self->name |
343 | . ") does not pass the type constraint because " |
ab76842e |
344 | . $type_constraint->get_message($value); |
946289d1 |
345 | } |
26fbace8 |
346 | |
946289d1 |
347 | my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) |
348 | ->get_meta_instance; |
26fbace8 |
349 | |
350 | $meta_instance->set_slot_value($instance, $attr_name, $value); |
351 | |
946289d1 |
352 | if (ref $value && $self->is_weak_ref) { |
26fbace8 |
353 | $meta_instance->weaken_slot_value($instance, $attr_name); |
946289d1 |
354 | } |
26fbace8 |
355 | |
946289d1 |
356 | if ($self->has_trigger) { |
357 | $self->trigger->($instance, $value, $self); |
358 | } |
359 | } |
360 | |
361 | sub get_value { |
362 | my ($self, $instance) = @_; |
26fbace8 |
363 | |
946289d1 |
364 | if ($self->is_lazy) { |
8de73ff1 |
365 | unless ($self->has_value($instance)) { |
366 | if ($self->has_default) { |
367 | my $default = $self->default($instance); |
759e4e8f |
368 | $self->set_initial_value($instance, $default); |
8de73ff1 |
369 | } |
370 | if ( $self->has_builder ){ |
a6c84c69 |
371 | if (my $builder = $instance->can($self->builder)){ |
759e4e8f |
372 | $self->set_initial_value($instance, $instance->$builder); |
a6c84c69 |
373 | } |
374 | else { |
375 | confess(blessed($instance) |
376 | . " does not support builder method '" |
377 | . $self->builder |
378 | . "' for attribute '" |
379 | . $self->name |
380 | . "'"); |
26fbace8 |
381 | } |
a6c84c69 |
382 | } |
383 | else { |
759e4e8f |
384 | $self->set_initial_value($instance, undef); |
26fbace8 |
385 | } |
8de73ff1 |
386 | } |
946289d1 |
387 | } |
26fbace8 |
388 | |
946289d1 |
389 | if ($self->should_auto_deref) { |
26fbace8 |
390 | |
946289d1 |
391 | my $type_constraint = $self->type_constraint; |
392 | |
393 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
394 | my $rv = $self->SUPER::get_value($instance); |
395 | return unless defined $rv; |
396 | return wantarray ? @{ $rv } : $rv; |
26fbace8 |
397 | } |
946289d1 |
398 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
399 | my $rv = $self->SUPER::get_value($instance); |
400 | return unless defined $rv; |
401 | return wantarray ? %{ $rv } : $rv; |
26fbace8 |
402 | } |
946289d1 |
403 | else { |
404 | confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; |
405 | } |
26fbace8 |
406 | |
946289d1 |
407 | } |
408 | else { |
26fbace8 |
409 | |
946289d1 |
410 | return $self->SUPER::get_value($instance); |
26fbace8 |
411 | } |
946289d1 |
412 | } |
a15dff8d |
413 | |
26fbace8 |
414 | ## installing accessors |
c0e30cf5 |
415 | |
d617b644 |
416 | sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } |
d7f17ebb |
417 | |
452bac1b |
418 | sub install_accessors { |
419 | my $self = shift; |
26fbace8 |
420 | $self->SUPER::install_accessors(@_); |
421 | |
452bac1b |
422 | if ($self->has_handles) { |
26fbace8 |
423 | |
452bac1b |
424 | # NOTE: |
425 | # Here we canonicalize the 'handles' option |
26fbace8 |
426 | # this will sort out any details and always |
427 | # return an hash of methods which we want |
452bac1b |
428 | # to delagate to, see that method for details |
429 | my %handles = $self->_canonicalize_handles(); |
26fbace8 |
430 | |
f3c4e20e |
431 | # find the accessor method for this attribute |
432 | my $accessor = $self->get_read_method_ref; |
433 | # then unpack it if we need too ... |
434 | $accessor = $accessor->body if blessed $accessor; |
26fbace8 |
435 | |
452bac1b |
436 | # install the delegation ... |
437 | my $associated_class = $self->associated_class; |
438 | foreach my $handle (keys %handles) { |
439 | my $method_to_call = $handles{$handle}; |
7dbbdcab |
440 | my $class_name = $associated_class->name; |
441 | my $name = "${class_name}::${handle}"; |
26fbace8 |
442 | |
452bac1b |
443 | (!$associated_class->has_method($handle)) |
444 | || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; |
26fbace8 |
445 | |
d022f632 |
446 | # NOTE: |
447 | # handles is not allowed to delegate |
26fbace8 |
448 | # any of these methods, as they will |
449 | # override the ones in your class, which |
d022f632 |
450 | # is almost certainly not what you want. |
4fe78472 |
451 | |
452 | # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something |
453 | #cluck("Not delegating method '$handle' because it is a core method") and |
454 | next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); |
26fbace8 |
455 | |
452bac1b |
456 | if ((reftype($method_to_call) || '') eq 'CODE') { |
7dbbdcab |
457 | $associated_class->add_method($handle => subname $name, $method_to_call); |
452bac1b |
458 | } |
459 | else { |
140001f0 |
460 | # NOTE: |
461 | # we used to do a goto here, but the |
462 | # goto didn't handle failure correctly |
463 | # (it just returned nothing), so I took |
464 | # that out. However, the more I thought |
465 | # about it, the less I liked it doing |
466 | # the goto, and I prefered the act of |
467 | # delegation being actually represented |
468 | # in the stack trace. |
469 | # - SL |
7dbbdcab |
470 | $associated_class->add_method($handle => subname $name, sub { |
f3c4e20e |
471 | my $proxy = (shift)->$accessor(); |
ccf49e80 |
472 | (defined $proxy) |
473 | || confess "Cannot delegate $handle to $method_to_call because " . |
474 | "the value of " . $self->name . " is not defined"; |
f4f3e701 |
475 | $proxy->$method_to_call(@_); |
452bac1b |
476 | }); |
477 | } |
478 | } |
479 | } |
26fbace8 |
480 | |
452bac1b |
481 | return; |
482 | } |
483 | |
98aae381 |
484 | # private methods to help delegation ... |
485 | |
452bac1b |
486 | sub _canonicalize_handles { |
487 | my $self = shift; |
488 | my $handles = $self->handles; |
c84f324f |
489 | if (my $handle_type = ref($handles)) { |
490 | if ($handle_type eq 'HASH') { |
491 | return %{$handles}; |
492 | } |
493 | elsif ($handle_type eq 'ARRAY') { |
494 | return map { $_ => $_ } @{$handles}; |
495 | } |
496 | elsif ($handle_type eq 'Regexp') { |
497 | ($self->has_type_constraint) |
498 | || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; |
26fbace8 |
499 | return map { ($_ => $_) } |
c84f324f |
500 | grep { /$handles/ } $self->_get_delegate_method_list; |
501 | } |
502 | elsif ($handle_type eq 'CODE') { |
503 | return $handles->($self, $self->_find_delegate_metaclass); |
504 | } |
505 | else { |
506 | confess "Unable to canonicalize the 'handles' option with $handles"; |
507 | } |
452bac1b |
508 | } |
509 | else { |
c84f324f |
510 | my $role_meta = eval { $handles->meta }; |
511 | if ($@) { |
26fbace8 |
512 | confess "Unable to canonicalize the 'handles' option with $handles because : $@"; |
c84f324f |
513 | } |
514 | |
515 | (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) |
516 | || confess "Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role"; |
26fbace8 |
517 | |
c84f324f |
518 | return map { $_ => $_ } ( |
26fbace8 |
519 | $role_meta->get_method_list, |
c84f324f |
520 | $role_meta->get_required_method_list |
521 | ); |
452bac1b |
522 | } |
523 | } |
524 | |
525 | sub _find_delegate_metaclass { |
526 | my $self = shift; |
98aae381 |
527 | if (my $class = $self->_isa_metadata) { |
26fbace8 |
528 | # if the class does have |
452bac1b |
529 | # a meta method, use it |
530 | return $class->meta if $class->can('meta'); |
26fbace8 |
531 | # otherwise we might be |
452bac1b |
532 | # dealing with a non-Moose |
26fbace8 |
533 | # class, and need to make |
452bac1b |
534 | # our own metaclass |
535 | return Moose::Meta::Class->initialize($class); |
536 | } |
98aae381 |
537 | elsif (my $role = $self->_does_metadata) { |
26fbace8 |
538 | # our role will always have |
452bac1b |
539 | # a meta method |
98aae381 |
540 | return $role->meta; |
452bac1b |
541 | } |
542 | else { |
543 | confess "Cannot find delegate metaclass for attribute " . $self->name; |
544 | } |
545 | } |
546 | |
547 | sub _get_delegate_method_list { |
548 | my $self = shift; |
549 | my $meta = $self->_find_delegate_metaclass; |
550 | if ($meta->isa('Class::MOP::Class')) { |
093b12c2 |
551 | return map { $_->{name} } # NOTE: !never! delegate &meta |
26fbace8 |
552 | grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } |
452bac1b |
553 | $meta->compute_all_applicable_methods; |
554 | } |
555 | elsif ($meta->isa('Moose::Meta::Role')) { |
26fbace8 |
556 | return $meta->get_method_list; |
452bac1b |
557 | } |
558 | else { |
559 | confess "Unable to recognize the delegate metaclass '$meta'"; |
560 | } |
561 | } |
562 | |
c0e30cf5 |
563 | 1; |
564 | |
565 | __END__ |
566 | |
567 | =pod |
568 | |
569 | =head1 NAME |
570 | |
6ba6d68c |
571 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
572 | |
573 | =head1 DESCRIPTION |
574 | |
26fbace8 |
575 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
576 | extensions. |
6ba6d68c |
577 | |
26fbace8 |
578 | For the most part, the only time you will ever encounter an |
579 | instance of this class is if you are doing some serious deep |
580 | introspection. To really understand this class, you need to refer |
6ba6d68c |
581 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
582 | |
c0e30cf5 |
583 | =head1 METHODS |
584 | |
6ba6d68c |
585 | =head2 Overridden methods |
586 | |
26fbace8 |
587 | These methods override methods in L<Class::MOP::Attribute> and add |
588 | Moose specific features. You can safely assume though that they |
6ba6d68c |
589 | will behave just as L<Class::MOP::Attribute> does. |
590 | |
c0e30cf5 |
591 | =over 4 |
592 | |
593 | =item B<new> |
594 | |
6e2840b7 |
595 | =item B<does> |
596 | |
d500266f |
597 | =item B<initialize_instance_slot> |
598 | |
452bac1b |
599 | =item B<install_accessors> |
600 | |
39b3bc94 |
601 | =item B<accessor_metaclass> |
602 | |
946289d1 |
603 | =item B<get_value> |
604 | |
605 | =item B<set_value> |
606 | |
bcbaa845 |
607 | eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; |
608 | if($@) { |
609 | print "Oops: $@\n"; |
610 | } |
611 | |
612 | I<Attribute (x) does not pass the type constraint (Int) with 'fourty-two'> |
613 | |
614 | Before setting the value, a check is made on the type constraint of |
615 | the attribute, if it has one, to see if the value passes it. If the |
616 | value fails to pass, the set operation dies with a L<Carp/confess>. |
617 | |
618 | Any coercion to convert values is done before checking the type constraint. |
619 | |
620 | To check a value against a type constraint before setting it, fetch the |
ec00fa75 |
621 | attribute instance using L<Class::MOP::Class/find_attribute_by_name>, |
bcbaa845 |
622 | fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint> |
623 | and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::RecipeX> |
624 | for an example. |
625 | |
a15dff8d |
626 | =back |
627 | |
6ba6d68c |
628 | =head2 Additional Moose features |
629 | |
26fbace8 |
630 | Moose attributes support type-constraint checking, weak reference |
631 | creation and type coercion. |
6ba6d68c |
632 | |
a15dff8d |
633 | =over 4 |
634 | |
9e93dd19 |
635 | =item B<clone_and_inherit_options> |
636 | |
26fbace8 |
637 | This is to support the C<has '+foo'> feature, it clones an attribute |
638 | from a superclass and allows a very specific set of changes to be made |
9e93dd19 |
639 | to the attribute. |
640 | |
a15dff8d |
641 | =item B<has_type_constraint> |
642 | |
6ba6d68c |
643 | Returns true if this meta-attribute has a type constraint. |
644 | |
a15dff8d |
645 | =item B<type_constraint> |
646 | |
26fbace8 |
647 | A read-only accessor for this meta-attribute's type constraint. For |
648 | more information on what you can do with this, see the documentation |
6ba6d68c |
649 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
650 | |
452bac1b |
651 | =item B<has_handles> |
652 | |
653 | Returns true if this meta-attribute performs delegation. |
654 | |
655 | =item B<handles> |
656 | |
657 | This returns the value which was passed into the handles option. |
658 | |
6ba6d68c |
659 | =item B<is_weak_ref> |
a15dff8d |
660 | |
02a0fb52 |
661 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
662 | |
ca01a97b |
663 | =item B<is_required> |
664 | |
02a0fb52 |
665 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
666 | |
667 | =item B<is_lazy> |
668 | |
02a0fb52 |
669 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
670 | |
26fbace8 |
671 | NOTE: lazy attributes, B<must> have a C<default> or C<builder> field set. |
672 | |
673 | =item B<is_lazy_build> |
674 | |
675 | Returns true if this meta-attribute should be initialized lazily through |
676 | the builder generated by lazy_build. Using C<lazy_build =E<gt> 1> will |
677 | make your attribute required and lazy. In addition it will set the builder, clearer |
678 | and predicate options for you using the following convention. |
679 | |
680 | #If your attribute name starts with an underscore: |
681 | has '_foo' => (lazy_build => 1); |
682 | #is the same as |
58f85113 |
683 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo); |
26fbace8 |
684 | # or |
58f85113 |
685 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); |
26fbace8 |
686 | |
687 | #If your attribute name does not start with an underscore: |
58f85113 |
688 | has 'foo' => (lazy_build => 1); |
689 | #is the same as |
690 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo); |
26fbace8 |
691 | # or |
58f85113 |
692 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); |
693 | |
694 | The reason for the different naming of the C<builder> is that the C<builder> |
695 | method is a private method while the C<clearer> and C<predicate> methods |
696 | are public methods. |
26fbace8 |
697 | |
698 | NOTE: This means your class should provide a method whose name matches the value |
58f85113 |
699 | of the builder part, in this case _build__foo or _build_foo. |
ca01a97b |
700 | |
34a66aa3 |
701 | =item B<should_coerce> |
4b598ea3 |
702 | |
02a0fb52 |
703 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
704 | |
536f0b17 |
705 | =item B<should_auto_deref> |
706 | |
26fbace8 |
707 | Returns true if this meta-attribute should perform automatic |
708 | auto-dereferencing. |
536f0b17 |
709 | |
26fbace8 |
710 | NOTE: This can only be done for attributes whose type constraint is |
536f0b17 |
711 | either I<ArrayRef> or I<HashRef>. |
712 | |
8c9d74e7 |
713 | =item B<has_trigger> |
714 | |
02a0fb52 |
715 | Returns true if this meta-attribute has a trigger set. |
716 | |
8c9d74e7 |
717 | =item B<trigger> |
718 | |
26fbace8 |
719 | This is a CODE reference which will be executed every time the |
720 | value of an attribute is assigned. The CODE ref will get two values, |
721 | the invocant and the new value. This can be used to handle I<basic> |
02a0fb52 |
722 | bi-directional relations. |
723 | |
ddbdc0cb |
724 | =item B<documentation> |
725 | |
26fbace8 |
726 | This is a string which contains the documentation for this attribute. |
ddbdc0cb |
727 | It serves no direct purpose right now, but it might in the future |
728 | in some kind of automated documentation system perhaps. |
729 | |
730 | =item B<has_documentation> |
731 | |
732 | Returns true if this meta-attribute has any documentation. |
733 | |
c0e30cf5 |
734 | =back |
735 | |
736 | =head1 BUGS |
737 | |
26fbace8 |
738 | All complex software has bugs lurking in it, and this module is no |
c0e30cf5 |
739 | exception. If you find a bug please either email me, or add the bug |
740 | to cpan-RT. |
741 | |
c0e30cf5 |
742 | =head1 AUTHOR |
743 | |
744 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
745 | |
98aae381 |
746 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
747 | |
c0e30cf5 |
748 | =head1 COPYRIGHT AND LICENSE |
749 | |
778db3ac |
750 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c0e30cf5 |
751 | |
752 | L<http://www.iinteractive.com> |
753 | |
754 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
755 | it under the same terms as Perl itself. |
c0e30cf5 |
756 | |
8a7a9c53 |
757 | =cut |