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; |
5e98d2b6 |
68 | foreach my $legal_option (qw(default coerce required documentation lazy handles builder)) { |
ce0e8d63 |
69 | if (exists $options{$legal_option}) { |
70 | $actual_options{$legal_option} = $options{$legal_option}; |
71 | delete $options{$legal_option}; |
72 | } |
73 | } |
26fbace8 |
74 | |
ce0e8d63 |
75 | if ($options{isa}) { |
76 | my $type_constraint; |
8de73ff1 |
77 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
78 | $type_constraint = $options{isa}; |
79 | } |
80 | else { |
81 | $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
82 | $options{isa} |
83 | ); |
84 | (defined $type_constraint) |
85 | || confess "Could not find the type constraint '" . $options{isa} . "'"; |
86 | } |
5e98d2b6 |
87 | |
8de73ff1 |
88 | $actual_options{type_constraint} = $type_constraint; |
ce0e8d63 |
89 | delete $options{isa}; |
90 | } |
26fbace8 |
91 | (scalar keys %options == 0) |
ce0e8d63 |
92 | || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; |
93 | $self->clone(%actual_options); |
1d768fb1 |
94 | } |
95 | |
96 | sub _process_options { |
97 | my ($class, $name, $options) = @_; |
8de73ff1 |
98 | |
f3c4e20e |
99 | if (exists $options->{is}) { |
8de73ff1 |
100 | if ($options->{is} eq 'ro') { |
101 | $options->{reader} ||= $name; |
102 | (!exists $options->{trigger}) |
7dbda458 |
103 | || confess "Cannot have a trigger on a read-only attribute $name"; |
8de73ff1 |
104 | } |
105 | elsif ($options->{is} eq 'rw') { |
106 | $options->{accessor} = $name; |
107 | ((reftype($options->{trigger}) || '') eq 'CODE') |
108 | || confess "Trigger must be a CODE ref" |
109 | if exists $options->{trigger}; |
110 | } |
111 | else { |
7dbda458 |
112 | confess "I do not understand this option (is => " . $options->{is} . ") on attribute $name" |
8de73ff1 |
113 | } |
f3c4e20e |
114 | } |
8de73ff1 |
115 | |
f3c4e20e |
116 | if (exists $options->{isa}) { |
f3c4e20e |
117 | if (exists $options->{does}) { |
118 | if (eval { $options->{isa}->can('does') }) { |
119 | ($options->{isa}->does($options->{does})) |
7dbda458 |
120 | || confess "Cannot have an isa option and a does option if the isa does not do the does on attribute $name"; |
f3c4e20e |
121 | } |
122 | else { |
7dbda458 |
123 | confess "Cannot have an isa option which cannot ->does() on attribute $name"; |
26fbace8 |
124 | } |
26fbace8 |
125 | } |
8de73ff1 |
126 | |
f3c4e20e |
127 | # allow for anon-subtypes here ... |
128 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
8de73ff1 |
129 | $options->{type_constraint} = $options->{isa}; |
130 | } |
131 | else { |
132 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
133 | $options->{isa} => { |
f3c4e20e |
134 | parent => Moose::Util::TypeConstraints::find_type_constraint('Object'), |
135 | constraint => sub { $_[0]->isa($options->{isa}) } |
26fbace8 |
136 | } |
8de73ff1 |
137 | ); |
138 | } |
f3c4e20e |
139 | } |
140 | elsif (exists $options->{does}) { |
141 | # allow for anon-subtypes here ... |
142 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
238b424d |
143 | $options->{type_constraint} = $options->{does}; |
8de73ff1 |
144 | } |
145 | else { |
146 | $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint( |
147 | $options->{does} => { |
f3c4e20e |
148 | parent => Moose::Util::TypeConstraints::find_type_constraint('Role'), |
238b424d |
149 | constraint => sub { |
150 | Moose::Util::does_role($_[0], $options->{does}) |
151 | } |
26fbace8 |
152 | } |
8de73ff1 |
153 | ); |
154 | } |
f3c4e20e |
155 | } |
8de73ff1 |
156 | |
f3c4e20e |
157 | if (exists $options->{coerce} && $options->{coerce}) { |
158 | (exists $options->{type_constraint}) |
7dbda458 |
159 | || confess "You cannot have coercion without specifying a type constraint on attribute $name"; |
160 | confess "You cannot have a weak reference to a coerced value on attribute $name" |
8de73ff1 |
161 | if $options->{weak_ref}; |
f3c4e20e |
162 | } |
8de73ff1 |
163 | |
f3c4e20e |
164 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
165 | (exists $options->{type_constraint}) |
7dbda458 |
166 | || confess "You cannot auto-dereference without specifying a type constraint on attribute $name"; |
f3c4e20e |
167 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
8de73ff1 |
168 | $options->{type_constraint}->is_a_type_of('HashRef')) |
7dbda458 |
169 | || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute $name"; |
f3c4e20e |
170 | } |
8de73ff1 |
171 | |
f3c4e20e |
172 | if (exists $options->{lazy_build} && $options->{lazy_build} == 1) { |
7dbda458 |
173 | confess("You can not use lazy_build and default for the same attribute $name") |
8de73ff1 |
174 | if exists $options->{default}; |
a6c84c69 |
175 | $options->{lazy} = 1; |
176 | $options->{required} = 1; |
177 | $options->{builder} ||= "_build_${name}"; |
178 | if ($name =~ /^_/) { |
f3c4e20e |
179 | $options->{clearer} ||= "_clear${name}"; |
180 | $options->{predicate} ||= "_has${name}"; |
a6c84c69 |
181 | } |
182 | else { |
f3c4e20e |
183 | $options->{clearer} ||= "clear_${name}"; |
184 | $options->{predicate} ||= "has_${name}"; |
26fbace8 |
185 | } |
f3c4e20e |
186 | } |
8de73ff1 |
187 | |
f3c4e20e |
188 | if (exists $options->{lazy} && $options->{lazy}) { |
9edba990 |
189 | (exists $options->{default} || defined $options->{builder} ) |
7dbda458 |
190 | || confess "You cannot have lazy attribute ($name) without specifying a default value for it"; |
f3c4e20e |
191 | } |
26fbace8 |
192 | |
9edba990 |
193 | if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) { |
7dbda458 |
194 | confess "You cannot have a required attribute ($name) without a default, builder, or an init_arg"; |
9edba990 |
195 | } |
196 | |
78cd1d3b |
197 | } |
c0e30cf5 |
198 | |
d500266f |
199 | sub initialize_instance_slot { |
ddd0ec20 |
200 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
201 | my $init_arg = $self->init_arg(); |
202 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
203 | |
26fbace8 |
204 | my $val; |
1ed0b94f |
205 | my $value_is_set; |
625d571f |
206 | if ( defined($init_arg) and exists $params->{$init_arg}) { |
d500266f |
207 | $val = $params->{$init_arg}; |
2c78d811 |
208 | $value_is_set = 1; |
d500266f |
209 | } |
210 | else { |
211 | # skip it if it's lazy |
212 | return if $self->is_lazy; |
213 | # and die if it's required and doesn't have a default value |
26fbace8 |
214 | confess "Attribute (" . $self->name . ") is required" |
215 | if $self->is_required && !$self->has_default && !$self->has_builder; |
ddd0ec20 |
216 | |
1ed0b94f |
217 | # if nothing was in the %params, we can use the |
218 | # attribute's default value (if it has one) |
219 | if ($self->has_default) { |
220 | $val = $self->default($instance); |
221 | $value_is_set = 1; |
a6c84c69 |
222 | } |
223 | elsif ($self->has_builder) { |
224 | if (my $builder = $instance->can($self->builder)){ |
1ed0b94f |
225 | $val = $instance->$builder; |
226 | $value_is_set = 1; |
a6c84c69 |
227 | } |
228 | else { |
0b26305c |
229 | confess(blessed($instance)." does not support builder method '".$self->builder."' for attribute '" . $self->name . "'"); |
1ed0b94f |
230 | } |
a0748c37 |
231 | } |
26fbace8 |
232 | } |
233 | |
1ed0b94f |
234 | return unless $value_is_set; |
235 | |
236 | if ($self->has_type_constraint) { |
237 | my $type_constraint = $self->type_constraint; |
238 | if ($self->should_coerce && $type_constraint->has_coercion) { |
239 | $val = $type_constraint->coerce($val); |
d500266f |
240 | } |
ab76842e |
241 | $type_constraint->check($val) |
688fcdda |
242 | || confess "Attribute (" |
243 | . $self->name |
244 | . ") does not pass the type constraint because: " |
245 | . $type_constraint->get_message($val); |
1ed0b94f |
246 | } |
ddd0ec20 |
247 | |
759e4e8f |
248 | $self->set_initial_value($instance, $val); |
26fbace8 |
249 | $meta_instance->weaken_slot_value($instance, $self->name) |
a6c84c69 |
250 | if ref $val && $self->is_weak_ref; |
d500266f |
251 | } |
252 | |
d617b644 |
253 | ## Slot management |
9e93dd19 |
254 | |
8abe9636 |
255 | # FIXME: |
256 | # this duplicates too much code from |
257 | # Class::MOP::Attribute, we need to |
258 | # refactor these bits eventually. |
259 | # - SL |
260 | sub _set_initial_slot_value { |
261 | my ($self, $meta_instance, $instance, $value) = @_; |
262 | |
263 | my $slot_name = $self->name; |
264 | |
265 | return $meta_instance->set_slot_value($instance, $slot_name, $value) |
266 | unless $self->has_initializer; |
267 | |
268 | my ($type_constraint, $can_coerce); |
269 | if ($self->has_type_constraint) { |
270 | $type_constraint = $self->type_constraint; |
271 | $can_coerce = ($self->should_coerce && $type_constraint->has_coercion); |
272 | } |
273 | |
274 | my $callback = sub { |
275 | my $val = shift; |
276 | if ($type_constraint) { |
277 | $val = $type_constraint->coerce($val) |
278 | if $can_coerce; |
279 | $type_constraint->check($val) |
280 | || confess "Attribute (" |
281 | . $slot_name |
282 | . ") does not pass the type constraint because: " |
283 | . $type_constraint->get_message($val); |
284 | } |
285 | $meta_instance->set_slot_value($instance, $slot_name, $val); |
286 | }; |
287 | |
288 | my $initializer = $self->initializer; |
289 | |
290 | # most things will just want to set a value, so make it first arg |
291 | $instance->$initializer($value, $callback, $self); |
292 | } |
293 | |
946289d1 |
294 | sub set_value { |
295 | my ($self, $instance, $value) = @_; |
26fbace8 |
296 | |
946289d1 |
297 | my $attr_name = $self->name; |
26fbace8 |
298 | |
946289d1 |
299 | if ($self->is_required) { |
26fbace8 |
300 | defined($value) |
946289d1 |
301 | || confess "Attribute ($attr_name) is required, so cannot be set to undef"; |
302 | } |
26fbace8 |
303 | |
946289d1 |
304 | if ($self->has_type_constraint) { |
26fbace8 |
305 | |
946289d1 |
306 | my $type_constraint = $self->type_constraint; |
26fbace8 |
307 | |
946289d1 |
308 | if ($self->should_coerce) { |
26fbace8 |
309 | $value = $type_constraint->coerce($value); |
688fcdda |
310 | } |
42bc21a4 |
311 | $type_constraint->_compiled_type_constraint->($value) |
688fcdda |
312 | || confess "Attribute (" |
313 | . $self->name |
314 | . ") does not pass the type constraint because " |
ab76842e |
315 | . $type_constraint->get_message($value); |
946289d1 |
316 | } |
26fbace8 |
317 | |
946289d1 |
318 | my $meta_instance = Class::MOP::Class->initialize(blessed($instance)) |
319 | ->get_meta_instance; |
26fbace8 |
320 | |
321 | $meta_instance->set_slot_value($instance, $attr_name, $value); |
322 | |
946289d1 |
323 | if (ref $value && $self->is_weak_ref) { |
26fbace8 |
324 | $meta_instance->weaken_slot_value($instance, $attr_name); |
946289d1 |
325 | } |
26fbace8 |
326 | |
946289d1 |
327 | if ($self->has_trigger) { |
328 | $self->trigger->($instance, $value, $self); |
329 | } |
330 | } |
331 | |
332 | sub get_value { |
333 | my ($self, $instance) = @_; |
26fbace8 |
334 | |
946289d1 |
335 | if ($self->is_lazy) { |
8de73ff1 |
336 | unless ($self->has_value($instance)) { |
337 | if ($self->has_default) { |
338 | my $default = $self->default($instance); |
759e4e8f |
339 | $self->set_initial_value($instance, $default); |
8de73ff1 |
340 | } |
341 | if ( $self->has_builder ){ |
a6c84c69 |
342 | if (my $builder = $instance->can($self->builder)){ |
759e4e8f |
343 | $self->set_initial_value($instance, $instance->$builder); |
a6c84c69 |
344 | } |
345 | else { |
346 | confess(blessed($instance) |
347 | . " does not support builder method '" |
348 | . $self->builder |
349 | . "' for attribute '" |
350 | . $self->name |
351 | . "'"); |
26fbace8 |
352 | } |
a6c84c69 |
353 | } |
354 | else { |
759e4e8f |
355 | $self->set_initial_value($instance, undef); |
26fbace8 |
356 | } |
8de73ff1 |
357 | } |
946289d1 |
358 | } |
26fbace8 |
359 | |
946289d1 |
360 | if ($self->should_auto_deref) { |
26fbace8 |
361 | |
946289d1 |
362 | my $type_constraint = $self->type_constraint; |
363 | |
364 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
365 | my $rv = $self->SUPER::get_value($instance); |
366 | return unless defined $rv; |
367 | return wantarray ? @{ $rv } : $rv; |
26fbace8 |
368 | } |
946289d1 |
369 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
370 | my $rv = $self->SUPER::get_value($instance); |
371 | return unless defined $rv; |
372 | return wantarray ? %{ $rv } : $rv; |
26fbace8 |
373 | } |
946289d1 |
374 | else { |
375 | confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; |
376 | } |
26fbace8 |
377 | |
946289d1 |
378 | } |
379 | else { |
26fbace8 |
380 | |
946289d1 |
381 | return $self->SUPER::get_value($instance); |
26fbace8 |
382 | } |
946289d1 |
383 | } |
a15dff8d |
384 | |
26fbace8 |
385 | ## installing accessors |
c0e30cf5 |
386 | |
d617b644 |
387 | sub accessor_metaclass { 'Moose::Meta::Method::Accessor' } |
d7f17ebb |
388 | |
452bac1b |
389 | sub install_accessors { |
390 | my $self = shift; |
26fbace8 |
391 | $self->SUPER::install_accessors(@_); |
392 | |
452bac1b |
393 | if ($self->has_handles) { |
26fbace8 |
394 | |
452bac1b |
395 | # NOTE: |
396 | # Here we canonicalize the 'handles' option |
26fbace8 |
397 | # this will sort out any details and always |
398 | # return an hash of methods which we want |
452bac1b |
399 | # to delagate to, see that method for details |
400 | my %handles = $self->_canonicalize_handles(); |
26fbace8 |
401 | |
f3c4e20e |
402 | # find the accessor method for this attribute |
403 | my $accessor = $self->get_read_method_ref; |
404 | # then unpack it if we need too ... |
405 | $accessor = $accessor->body if blessed $accessor; |
26fbace8 |
406 | |
452bac1b |
407 | # install the delegation ... |
408 | my $associated_class = $self->associated_class; |
409 | foreach my $handle (keys %handles) { |
410 | my $method_to_call = $handles{$handle}; |
7dbbdcab |
411 | my $class_name = $associated_class->name; |
412 | my $name = "${class_name}::${handle}"; |
26fbace8 |
413 | |
452bac1b |
414 | (!$associated_class->has_method($handle)) |
415 | || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; |
26fbace8 |
416 | |
d022f632 |
417 | # NOTE: |
418 | # handles is not allowed to delegate |
26fbace8 |
419 | # any of these methods, as they will |
420 | # override the ones in your class, which |
d022f632 |
421 | # is almost certainly not what you want. |
4fe78472 |
422 | |
423 | # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something |
424 | #cluck("Not delegating method '$handle' because it is a core method") and |
425 | next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle); |
26fbace8 |
426 | |
452bac1b |
427 | if ((reftype($method_to_call) || '') eq 'CODE') { |
7dbbdcab |
428 | $associated_class->add_method($handle => subname $name, $method_to_call); |
452bac1b |
429 | } |
430 | else { |
140001f0 |
431 | # NOTE: |
432 | # we used to do a goto here, but the |
433 | # goto didn't handle failure correctly |
434 | # (it just returned nothing), so I took |
435 | # that out. However, the more I thought |
436 | # about it, the less I liked it doing |
437 | # the goto, and I prefered the act of |
438 | # delegation being actually represented |
439 | # in the stack trace. |
440 | # - SL |
7dbbdcab |
441 | $associated_class->add_method($handle => subname $name, sub { |
f3c4e20e |
442 | my $proxy = (shift)->$accessor(); |
ccf49e80 |
443 | (defined $proxy) |
444 | || confess "Cannot delegate $handle to $method_to_call because " . |
445 | "the value of " . $self->name . " is not defined"; |
f4f3e701 |
446 | $proxy->$method_to_call(@_); |
452bac1b |
447 | }); |
448 | } |
449 | } |
450 | } |
26fbace8 |
451 | |
452bac1b |
452 | return; |
453 | } |
454 | |
98aae381 |
455 | # private methods to help delegation ... |
456 | |
452bac1b |
457 | sub _canonicalize_handles { |
458 | my $self = shift; |
459 | my $handles = $self->handles; |
c84f324f |
460 | if (my $handle_type = ref($handles)) { |
461 | if ($handle_type eq 'HASH') { |
462 | return %{$handles}; |
463 | } |
464 | elsif ($handle_type eq 'ARRAY') { |
465 | return map { $_ => $_ } @{$handles}; |
466 | } |
467 | elsif ($handle_type eq 'Regexp') { |
468 | ($self->has_type_constraint) |
469 | || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; |
26fbace8 |
470 | return map { ($_ => $_) } |
c84f324f |
471 | grep { /$handles/ } $self->_get_delegate_method_list; |
472 | } |
473 | elsif ($handle_type eq 'CODE') { |
474 | return $handles->($self, $self->_find_delegate_metaclass); |
475 | } |
476 | else { |
477 | confess "Unable to canonicalize the 'handles' option with $handles"; |
478 | } |
452bac1b |
479 | } |
480 | else { |
c84f324f |
481 | my $role_meta = eval { $handles->meta }; |
482 | if ($@) { |
26fbace8 |
483 | confess "Unable to canonicalize the 'handles' option with $handles because : $@"; |
c84f324f |
484 | } |
485 | |
486 | (blessed $role_meta && $role_meta->isa('Moose::Meta::Role')) |
487 | || confess "Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role"; |
26fbace8 |
488 | |
c84f324f |
489 | return map { $_ => $_ } ( |
26fbace8 |
490 | $role_meta->get_method_list, |
c84f324f |
491 | $role_meta->get_required_method_list |
492 | ); |
452bac1b |
493 | } |
494 | } |
495 | |
496 | sub _find_delegate_metaclass { |
497 | my $self = shift; |
98aae381 |
498 | if (my $class = $self->_isa_metadata) { |
26fbace8 |
499 | # if the class does have |
452bac1b |
500 | # a meta method, use it |
501 | return $class->meta if $class->can('meta'); |
26fbace8 |
502 | # otherwise we might be |
452bac1b |
503 | # dealing with a non-Moose |
26fbace8 |
504 | # class, and need to make |
452bac1b |
505 | # our own metaclass |
506 | return Moose::Meta::Class->initialize($class); |
507 | } |
98aae381 |
508 | elsif (my $role = $self->_does_metadata) { |
26fbace8 |
509 | # our role will always have |
452bac1b |
510 | # a meta method |
98aae381 |
511 | return $role->meta; |
452bac1b |
512 | } |
513 | else { |
514 | confess "Cannot find delegate metaclass for attribute " . $self->name; |
515 | } |
516 | } |
517 | |
518 | sub _get_delegate_method_list { |
519 | my $self = shift; |
520 | my $meta = $self->_find_delegate_metaclass; |
521 | if ($meta->isa('Class::MOP::Class')) { |
093b12c2 |
522 | return map { $_->{name} } # NOTE: !never! delegate &meta |
26fbace8 |
523 | grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } |
452bac1b |
524 | $meta->compute_all_applicable_methods; |
525 | } |
526 | elsif ($meta->isa('Moose::Meta::Role')) { |
26fbace8 |
527 | return $meta->get_method_list; |
452bac1b |
528 | } |
529 | else { |
530 | confess "Unable to recognize the delegate metaclass '$meta'"; |
531 | } |
532 | } |
533 | |
c0e30cf5 |
534 | 1; |
535 | |
536 | __END__ |
537 | |
538 | =pod |
539 | |
540 | =head1 NAME |
541 | |
6ba6d68c |
542 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
543 | |
544 | =head1 DESCRIPTION |
545 | |
26fbace8 |
546 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
547 | extensions. |
6ba6d68c |
548 | |
26fbace8 |
549 | For the most part, the only time you will ever encounter an |
550 | instance of this class is if you are doing some serious deep |
551 | introspection. To really understand this class, you need to refer |
6ba6d68c |
552 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
553 | |
c0e30cf5 |
554 | =head1 METHODS |
555 | |
6ba6d68c |
556 | =head2 Overridden methods |
557 | |
26fbace8 |
558 | These methods override methods in L<Class::MOP::Attribute> and add |
559 | Moose specific features. You can safely assume though that they |
6ba6d68c |
560 | will behave just as L<Class::MOP::Attribute> does. |
561 | |
c0e30cf5 |
562 | =over 4 |
563 | |
564 | =item B<new> |
565 | |
6e2840b7 |
566 | =item B<does> |
567 | |
d500266f |
568 | =item B<initialize_instance_slot> |
569 | |
452bac1b |
570 | =item B<install_accessors> |
571 | |
39b3bc94 |
572 | =item B<accessor_metaclass> |
573 | |
946289d1 |
574 | =item B<get_value> |
575 | |
576 | =item B<set_value> |
577 | |
bcbaa845 |
578 | eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') }; |
579 | if($@) { |
580 | print "Oops: $@\n"; |
581 | } |
582 | |
583 | I<Attribute (x) does not pass the type constraint (Int) with 'fourty-two'> |
584 | |
585 | Before setting the value, a check is made on the type constraint of |
586 | the attribute, if it has one, to see if the value passes it. If the |
587 | value fails to pass, the set operation dies with a L<Carp/confess>. |
588 | |
589 | Any coercion to convert values is done before checking the type constraint. |
590 | |
591 | To check a value against a type constraint before setting it, fetch the |
ec00fa75 |
592 | attribute instance using L<Class::MOP::Class/find_attribute_by_name>, |
bcbaa845 |
593 | fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint> |
594 | and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::RecipeX> |
595 | for an example. |
596 | |
a15dff8d |
597 | =back |
598 | |
6ba6d68c |
599 | =head2 Additional Moose features |
600 | |
26fbace8 |
601 | Moose attributes support type-constraint checking, weak reference |
602 | creation and type coercion. |
6ba6d68c |
603 | |
a15dff8d |
604 | =over 4 |
605 | |
9e93dd19 |
606 | =item B<clone_and_inherit_options> |
607 | |
26fbace8 |
608 | This is to support the C<has '+foo'> feature, it clones an attribute |
609 | from a superclass and allows a very specific set of changes to be made |
9e93dd19 |
610 | to the attribute. |
611 | |
a15dff8d |
612 | =item B<has_type_constraint> |
613 | |
6ba6d68c |
614 | Returns true if this meta-attribute has a type constraint. |
615 | |
a15dff8d |
616 | =item B<type_constraint> |
617 | |
26fbace8 |
618 | A read-only accessor for this meta-attribute's type constraint. For |
619 | more information on what you can do with this, see the documentation |
6ba6d68c |
620 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
621 | |
452bac1b |
622 | =item B<has_handles> |
623 | |
624 | Returns true if this meta-attribute performs delegation. |
625 | |
626 | =item B<handles> |
627 | |
628 | This returns the value which was passed into the handles option. |
629 | |
6ba6d68c |
630 | =item B<is_weak_ref> |
a15dff8d |
631 | |
02a0fb52 |
632 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
633 | |
ca01a97b |
634 | =item B<is_required> |
635 | |
02a0fb52 |
636 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
637 | |
638 | =item B<is_lazy> |
639 | |
02a0fb52 |
640 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
641 | |
26fbace8 |
642 | NOTE: lazy attributes, B<must> have a C<default> or C<builder> field set. |
643 | |
644 | =item B<is_lazy_build> |
645 | |
646 | Returns true if this meta-attribute should be initialized lazily through |
647 | the builder generated by lazy_build. Using C<lazy_build =E<gt> 1> will |
648 | make your attribute required and lazy. In addition it will set the builder, clearer |
649 | and predicate options for you using the following convention. |
650 | |
651 | #If your attribute name starts with an underscore: |
652 | has '_foo' => (lazy_build => 1); |
653 | #is the same as |
58f85113 |
654 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo); |
26fbace8 |
655 | # or |
58f85113 |
656 | has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo}); |
26fbace8 |
657 | |
658 | #If your attribute name does not start with an underscore: |
58f85113 |
659 | has 'foo' => (lazy_build => 1); |
660 | #is the same as |
661 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo); |
26fbace8 |
662 | # or |
58f85113 |
663 | has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo}); |
664 | |
665 | The reason for the different naming of the C<builder> is that the C<builder> |
666 | method is a private method while the C<clearer> and C<predicate> methods |
667 | are public methods. |
26fbace8 |
668 | |
669 | NOTE: This means your class should provide a method whose name matches the value |
58f85113 |
670 | of the builder part, in this case _build__foo or _build_foo. |
ca01a97b |
671 | |
34a66aa3 |
672 | =item B<should_coerce> |
4b598ea3 |
673 | |
02a0fb52 |
674 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
675 | |
536f0b17 |
676 | =item B<should_auto_deref> |
677 | |
26fbace8 |
678 | Returns true if this meta-attribute should perform automatic |
679 | auto-dereferencing. |
536f0b17 |
680 | |
26fbace8 |
681 | NOTE: This can only be done for attributes whose type constraint is |
536f0b17 |
682 | either I<ArrayRef> or I<HashRef>. |
683 | |
8c9d74e7 |
684 | =item B<has_trigger> |
685 | |
02a0fb52 |
686 | Returns true if this meta-attribute has a trigger set. |
687 | |
8c9d74e7 |
688 | =item B<trigger> |
689 | |
26fbace8 |
690 | This is a CODE reference which will be executed every time the |
691 | value of an attribute is assigned. The CODE ref will get two values, |
692 | the invocant and the new value. This can be used to handle I<basic> |
02a0fb52 |
693 | bi-directional relations. |
694 | |
ddbdc0cb |
695 | =item B<documentation> |
696 | |
26fbace8 |
697 | This is a string which contains the documentation for this attribute. |
ddbdc0cb |
698 | It serves no direct purpose right now, but it might in the future |
699 | in some kind of automated documentation system perhaps. |
700 | |
701 | =item B<has_documentation> |
702 | |
703 | Returns true if this meta-attribute has any documentation. |
704 | |
c0e30cf5 |
705 | =back |
706 | |
707 | =head1 BUGS |
708 | |
26fbace8 |
709 | All complex software has bugs lurking in it, and this module is no |
c0e30cf5 |
710 | exception. If you find a bug please either email me, or add the bug |
711 | to cpan-RT. |
712 | |
c0e30cf5 |
713 | =head1 AUTHOR |
714 | |
715 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
716 | |
98aae381 |
717 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
718 | |
c0e30cf5 |
719 | =head1 COPYRIGHT AND LICENSE |
720 | |
778db3ac |
721 | Copyright 2006-2008 by Infinity Interactive, Inc. |
c0e30cf5 |
722 | |
723 | L<http://www.iinteractive.com> |
724 | |
725 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
726 | it under the same terms as Perl itself. |
c0e30cf5 |
727 | |
8a7a9c53 |
728 | =cut |