Commit | Line | Data |
306290e8 |
1 | package Mouse::Meta::Attribute; |
bc69ee88 |
2 | use Mouse::Util qw(:meta); # enables strict and warnings |
c3398f5b |
3 | |
2efc0af1 |
4 | use Carp (); |
2efc0af1 |
5 | |
684db121 |
6 | use Mouse::Meta::TypeConstraint; |
d7d8d49b |
7 | |
87ca293b |
8 | sub _process_options{ |
9 | my($class, $name, $args) = @_; |
c3398f5b |
10 | |
04493075 |
11 | # XXX: for backward compatibility (with method modifiers) |
12 | if($class->can('canonicalize_args') != \&canonicalize_args){ |
13 | %{$args} = $class->canonicalize_args($name, %{$args}); |
14 | } |
15 | |
2efc0af1 |
16 | # taken from Class::MOP::Attribute::new |
17 | |
18 | defined($name) |
19 | or $class->throw_error('You must provide a name for the attribute'); |
2e7e86c6 |
20 | |
1b9e472d |
21 | if(!exists $args->{init_arg}){ |
22 | $args->{init_arg} = $name; |
2efc0af1 |
23 | } |
24 | |
25 | # 'required' requires eigher 'init_arg', 'builder', or 'default' |
1b9e472d |
26 | my $can_be_required = defined( $args->{init_arg} ); |
2efc0af1 |
27 | |
1b9e472d |
28 | if(exists $args->{builder}){ |
c6d8f5ca |
29 | # XXX: |
30 | # Moose refuses a CODE ref builder, but Mouse doesn't for backward compatibility |
31 | # This feature will be changed in a future. (gfx) |
121acb8a |
32 | $class->throw_error('builder must be a defined scalar value which is a method name') |
c6d8f5ca |
33 | #if ref $args->{builder} || !defined $args->{builder}; |
34 | if !defined $args->{builder}; |
2efc0af1 |
35 | |
36 | $can_be_required++; |
37 | } |
1b9e472d |
38 | elsif(exists $args->{default}){ |
39 | if(ref $args->{default} && ref($args->{default}) ne 'CODE'){ |
2efc0af1 |
40 | $class->throw_error("References are not allowed as default values, you must " |
41 | . "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"); |
42 | } |
43 | $can_be_required++; |
44 | } |
45 | |
1b9e472d |
46 | if( $args->{required} && !$can_be_required ) { |
121acb8a |
47 | $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg"); |
2efc0af1 |
48 | } |
49 | |
1b9e472d |
50 | # taken from Mouse::Meta::Attribute->new and _process_args-> |
2efc0af1 |
51 | |
1b9e472d |
52 | if(exists $args->{is}){ |
53 | my $is = $args->{is}; |
2efc0af1 |
54 | |
55 | if($is eq 'ro'){ |
1b9e472d |
56 | $args->{reader} ||= $name; |
2efc0af1 |
57 | } |
58 | elsif($is eq 'rw'){ |
1b9e472d |
59 | if(exists $args->{writer}){ |
60 | $args->{reader} ||= $name; |
2efc0af1 |
61 | } |
62 | else{ |
1b9e472d |
63 | $args->{accessor} ||= $name; |
2efc0af1 |
64 | } |
65 | } |
66 | elsif($is eq 'bare'){ |
67 | # do nothing, but don't complain (later) about missing methods |
68 | } |
69 | else{ |
70 | $is = 'undef' if !defined $is; |
71 | $class->throw_error("I do not understand this option (is => $is) on attribute ($name)"); |
72 | } |
73 | } |
74 | |
75 | my $tc; |
1b9e472d |
76 | if(exists $args->{isa}){ |
77 | $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($args->{isa}); |
2efc0af1 |
78 | } |
1b9e472d |
79 | elsif(exists $args->{does}){ |
9f74c401 |
80 | $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($args->{does}); |
2efc0af1 |
81 | } |
1b9e472d |
82 | $tc = $args->{type_constraint}; |
2efc0af1 |
83 | |
1b9e472d |
84 | if($args->{coerce}){ |
2efc0af1 |
85 | defined($tc) |
86 | || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)"); |
87 | |
1b9e472d |
88 | $args->{weak_ref} |
121acb8a |
89 | && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)"); |
2efc0af1 |
90 | } |
91 | |
1b9e472d |
92 | if ($args->{lazy_build}) { |
93 | exists($args->{default}) |
121acb8a |
94 | && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)"); |
95 | |
1b9e472d |
96 | $args->{lazy} = 1; |
97 | $args->{builder} ||= "_build_${name}"; |
121acb8a |
98 | if ($name =~ /^_/) { |
1b9e472d |
99 | $args->{clearer} ||= "_clear${name}"; |
100 | $args->{predicate} ||= "_has${name}"; |
121acb8a |
101 | } |
102 | else { |
1b9e472d |
103 | $args->{clearer} ||= "clear_${name}"; |
104 | $args->{predicate} ||= "has_${name}"; |
121acb8a |
105 | } |
2efc0af1 |
106 | } |
107 | |
1b9e472d |
108 | if ($args->{auto_deref}) { |
121acb8a |
109 | defined($tc) |
110 | || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)"); |
2efc0af1 |
111 | |
121acb8a |
112 | ( $tc->is_a_type_of('ArrayRef') || $tc->is_a_type_of('HashRef') ) |
113 | || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"); |
2efc0af1 |
114 | } |
115 | |
1b9e472d |
116 | if (exists $args->{trigger}) { |
117 | ('CODE' eq ref $args->{trigger}) |
121acb8a |
118 | || $class->throw_error("Trigger must be a CODE ref on attribute ($name)"); |
2efc0af1 |
119 | } |
45959ffa |
120 | |
1b9e472d |
121 | if ($args->{lazy}) { |
122 | (exists $args->{default} || defined $args->{builder}) |
121acb8a |
123 | || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it"); |
2efc0af1 |
124 | } |
90fe520e |
125 | |
87ca293b |
126 | return; |
127 | } |
128 | |
129 | sub new { |
130 | my $class = shift; |
131 | my $name = shift; |
132 | |
133 | my %args = (@_ == 1) ? %{ $_[0] } : @_; |
134 | |
135 | $class->_process_options($name, \%args); |
136 | |
137 | $args{name} = $name; |
138 | |
926290ac |
139 | my $self = bless \%args, $class; |
2efc0af1 |
140 | |
1b9e472d |
141 | # extra attributes |
142 | if($class ne __PACKAGE__){ |
926290ac |
143 | $class->meta->_initialize_object($self, \%args); |
90fe520e |
144 | } |
c3398f5b |
145 | |
2efc0af1 |
146 | # XXX: there is no fast way to check attribute validity |
1b9e472d |
147 | # my @bad = ...; |
2efc0af1 |
148 | # if(@bad){ |
149 | # @bad = sort @bad; |
150 | # Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad"); |
151 | # } |
152 | |
926290ac |
153 | return $self; |
c3398f5b |
154 | } |
155 | |
43165725 |
156 | sub has_read_method { $_[0]->has_reader || $_[0]->has_accessor } |
157 | sub has_write_method { $_[0]->has_writer || $_[0]->has_accessor } |
1b9e472d |
158 | |
df77fd72 |
159 | sub _create_args { # DEPRECATED |
1bfebf5f |
160 | $_[0]->{_create_args} = $_[1] if @_ > 1; |
161 | $_[0]->{_create_args} |
162 | } |
163 | |
87ca293b |
164 | sub interpolate_class{ |
8cf51b82 |
165 | my($class, $args) = @_; |
c3398f5b |
166 | |
1b9e472d |
167 | if(my $metaclass = delete $args->{metaclass}){ |
168 | $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass ); |
169 | } |
1bfebf5f |
170 | |
87ca293b |
171 | my @traits; |
1b9e472d |
172 | if(my $traits_ref = delete $args->{traits}){ |
87ca293b |
173 | |
f3f04eed |
174 | for (my $i = 0; $i < @{$traits_ref}; $i++) { |
175 | my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1); |
b2500191 |
176 | |
f3f04eed |
177 | next if $class->does($trait); |
74be9f76 |
178 | |
f3f04eed |
179 | push @traits, $trait; |
1b9e472d |
180 | |
f3f04eed |
181 | # are there options? |
182 | push @traits, $traits_ref->[++$i] |
183 | if ref($traits_ref->[$i+1]); |
184 | } |
c3398f5b |
185 | |
1b9e472d |
186 | if (@traits) { |
187 | $class = Mouse::Meta::Class->create_anon_class( |
188 | superclasses => [ $class ], |
189 | roles => \@traits, |
190 | cache => 1, |
191 | )->name; |
1b9e472d |
192 | } |
74be9f76 |
193 | } |
194 | |
87ca293b |
195 | return( $class, @traits ); |
1b9e472d |
196 | } |
197 | |
df77fd72 |
198 | sub canonicalize_args{ # DEPRECATED |
1b9e472d |
199 | my ($self, $name, %args) = @_; |
200 | |
201 | Carp::cluck("$self->canonicalize_args has been deprecated." |
04493075 |
202 | . "Use \$self->_process_options instead.") |
8aba926d |
203 | if Mouse::Util::_MOUSE_VERBOSE; |
1b9e472d |
204 | |
205 | return %args; |
206 | } |
207 | |
ce5920b7 |
208 | sub create { # DEPRECATED |
1b9e472d |
209 | my ($self, $class, $name, %args) = @_; |
210 | |
211 | Carp::cluck("$self->create has been deprecated." |
04493075 |
212 | . "Use \$meta->add_attribute and \$attr->install_accessors instead.") |
8aba926d |
213 | if Mouse::Util::_MOUSE_VERBOSE; |
1b9e472d |
214 | |
215 | # noop |
216 | return $self; |
c3398f5b |
217 | } |
218 | |
ffbbf459 |
219 | sub _coerce_and_verify { |
220 | my($self, $value, $instance) = @_; |
221 | |
222 | my $type_constraint = $self->{type_constraint}; |
4331a3f9 |
223 | return $value if !defined $type_constraint; |
ffbbf459 |
224 | |
225 | if ($self->should_coerce && $type_constraint->has_coercion) { |
226 | $value = $type_constraint->coerce($value); |
227 | } |
228 | |
ffbbf459 |
229 | $self->verify_against_type_constraint($value); |
230 | |
231 | return $value; |
232 | } |
233 | |
20e25eb9 |
234 | sub verify_against_type_constraint { |
f55f60dd |
235 | my ($self, $value) = @_; |
5aa30ced |
236 | |
ffbbf459 |
237 | my $type_constraint = $self->{type_constraint}; |
4331a3f9 |
238 | return 1 if !$type_constraint; |
ffbbf459 |
239 | return 1 if $type_constraint->check($value); |
5aa30ced |
240 | |
ffbbf459 |
241 | $self->verify_type_constraint_error($self->name, $value, $type_constraint); |
b3b74cc6 |
242 | } |
5aa30ced |
243 | |
b3b74cc6 |
244 | sub verify_type_constraint_error { |
245 | my($self, $name, $value, $type) = @_; |
4331a3f9 |
246 | $self->throw_error("Attribute ($name) does not pass the type constraint because: " |
247 | . $type->get_message($value)); |
5aa30ced |
248 | } |
249 | |
df77fd72 |
250 | sub coerce_constraint { # DEPRECATED |
8a7f2a8a |
251 | my $type = $_[0]->{type_constraint} |
252 | or return $_[1]; |
e763d56e |
253 | |
254 | Carp::cluck("coerce_constraint() has been deprecated, which was an internal utility anyway"); |
255 | |
7ca5c5fb |
256 | return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $type, $_[1]); |
4188b837 |
257 | } |
258 | |
1b9e472d |
259 | sub clone_and_inherit_options{ |
8cf51b82 |
260 | my($self, %args) = @_; |
261 | |
262 | my($attribute_class, @traits) = ref($self)->interpolate_class(\%args); |
1b9e472d |
263 | |
8cf51b82 |
264 | $args{traits} = \@traits if @traits; |
4f41d79b |
265 | # do not inherit the 'handles' attribute |
266 | foreach my $name(keys %{$self}){ |
267 | if(!exists $args{$name} && $name ne 'handles'){ |
268 | $args{$name} = $self->{$name}; |
269 | } |
270 | } |
271 | return $attribute_class->new($self->name, %args); |
1b9e472d |
272 | } |
273 | |
df77fd72 |
274 | sub clone_parent { # DEPRECATED |
1bfebf5f |
275 | my $self = shift; |
276 | my $class = shift; |
277 | my $name = shift; |
278 | my %args = ($self->get_parent_args($class, $name), @_); |
279 | |
1b9e472d |
280 | Carp::cluck("$self->clone_parent has been deprecated." |
04493075 |
281 | . "Use \$meta->add_attribute and \$attr->install_accessors instead.") |
8aba926d |
282 | if Mouse::Util::_MOUSE_VERBOSE; |
1b9e472d |
283 | |
7ca5c5fb |
284 | $self->clone_and_inherited_args($class, $name, %args); |
1bfebf5f |
285 | } |
286 | |
df77fd72 |
287 | sub get_parent_args { # DEPRECATED |
1bfebf5f |
288 | my $self = shift; |
289 | my $class = shift; |
290 | my $name = shift; |
291 | |
724c77c0 |
292 | for my $super ($class->linearized_isa) { |
bb733405 |
293 | my $super_attr = $super->can("meta") && $super->meta->get_attribute($name) |
1bfebf5f |
294 | or next; |
295 | return %{ $super_attr->_create_args }; |
296 | } |
297 | |
fce211ae |
298 | $self->throw_error("Could not find an attribute by the name of '$name' to inherit from"); |
299 | } |
300 | |
2a464664 |
301 | |
0126c27c |
302 | sub get_read_method { |
751de1a1 |
303 | return $_[0]->reader || $_[0]->accessor |
df77fd72 |
304 | } |
0126c27c |
305 | sub get_write_method { |
751de1a1 |
306 | return $_[0]->writer || $_[0]->accessor |
307 | } |
308 | |
309 | sub _get_accessor_method_ref { |
310 | my($self, $type, $generator) = @_; |
311 | |
312 | my $metaclass = $self->associated_class |
313 | || $self->throw_error('No asocciated class for ' . $self->name); |
314 | |
315 | my $accessor = $self->$type(); |
316 | if($accessor){ |
317 | return $metaclass->get_method_body($accessor); |
318 | } |
319 | else{ |
320 | return $self->accessor_metaclass->$generator($self, $metaclass); |
321 | } |
df77fd72 |
322 | } |
2a464664 |
323 | |
324 | sub get_read_method_ref{ |
325 | my($self) = @_; |
751de1a1 |
326 | return $self->{_read_method_ref} ||= $self->_get_accessor_method_ref('get_read_method', '_generate_reader'); |
2a464664 |
327 | } |
328 | |
329 | sub get_write_method_ref{ |
330 | my($self) = @_; |
751de1a1 |
331 | return $self->{_write_method_ref} ||= $self->_get_accessor_method_ref('get_write_method', '_generate_writer'); |
332 | } |
2a464664 |
333 | |
751de1a1 |
334 | sub set_value { |
335 | my($self, $object, $value) = @_; |
336 | return $self->get_write_method_ref()->($object, $value); |
337 | } |
338 | |
339 | sub get_value { |
340 | my($self, $object) = @_; |
341 | return $self->get_read_method_ref()->($object); |
2a464664 |
342 | } |
343 | |
751de1a1 |
344 | sub has_value { |
345 | my($self, $object) = @_; |
060f9228 |
346 | my $accessor_ref = $self->{_predicate_ref} |
751de1a1 |
347 | ||= $self->_get_accessor_method_ref('predicate', '_generate_predicate'); |
348 | |
060f9228 |
349 | return $accessor_ref->($object); |
751de1a1 |
350 | } |
351 | |
352 | sub clear_value { |
353 | my($self, $object) = @_; |
060f9228 |
354 | my $accessor_ref = $self->{_crealer_ref} |
751de1a1 |
355 | ||= $self->_get_accessor_method_ref('clearer', '_generate_clearer'); |
356 | |
060f9228 |
357 | return $accessor_ref->($object); |
751de1a1 |
358 | } |
359 | |
360 | |
04493075 |
361 | sub associate_method{ |
e5e22afd |
362 | my ($attribute, $method_name) = @_; |
04493075 |
363 | $attribute->{associated_methods}++; |
364 | return; |
365 | } |
366 | |
1b9e472d |
367 | sub install_accessors{ |
368 | my($attribute) = @_; |
369 | |
93540011 |
370 | my $metaclass = $attribute->associated_class; |
4ab51fb0 |
371 | my $accessor_class = $attribute->accessor_metaclass; |
1b9e472d |
372 | |
4ab51fb0 |
373 | foreach my $type(qw(accessor reader writer predicate clearer)){ |
1b9e472d |
374 | if(exists $attribute->{$type}){ |
4ab51fb0 |
375 | my $generator = '_generate_' . $type; |
376 | my $code = $accessor_class->$generator($attribute, $metaclass); |
377 | $metaclass->add_method($attribute->{$type} => $code); |
e5e22afd |
378 | $attribute->associate_method($attribute->{$type}); |
4ab51fb0 |
379 | } |
380 | } |
7ca5c5fb |
381 | |
4ab51fb0 |
382 | # install delegation |
383 | if(exists $attribute->{handles}){ |
384 | my %handles = $attribute->_canonicalize_handles($attribute->{handles}); |
feaa7084 |
385 | |
cbb81058 |
386 | while(my($handle, $method_to_call) = each %handles){ |
387 | $metaclass->add_method($handle => |
388 | $attribute->_make_delegation_method( |
389 | $handle, $method_to_call)); |
4ab51fb0 |
390 | |
cbb81058 |
391 | $attribute->associate_method($handle); |
1b9e472d |
392 | } |
393 | } |
394 | |
395 | if($attribute->can('create') != \&create){ |
7ca5c5fb |
396 | # backword compatibility |
1b9e472d |
397 | $attribute->create($metaclass, $attribute->name, %{$attribute}); |
398 | } |
399 | |
400 | return; |
401 | } |
402 | |
cbb81058 |
403 | sub delegation_metaclass() { 'Mouse::Meta::Method::Delegation' } |
404 | |
405 | sub _canonicalize_handles { |
406 | my($self, $handles) = @_; |
407 | |
408 | if (ref($handles) eq 'HASH') { |
409 | return %$handles; |
410 | } |
411 | elsif (ref($handles) eq 'ARRAY') { |
412 | return map { $_ => $_ } @$handles; |
413 | } |
414 | elsif (ref($handles) eq 'Regexp') { |
415 | my $class_or_role = ($self->{isa} || $self->{does}) |
416 | || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)"); |
417 | |
418 | my $meta = Mouse::Meta::Class->initialize("$class_or_role"); # "" for stringify |
419 | return map { $_ => $_ } |
420 | grep { !Mouse::Object->can($_) && $_ =~ $handles } |
421 | Mouse::Util::is_a_metarole($meta) |
422 | ? $meta->get_method_list |
423 | : $meta->get_all_method_names; |
424 | } |
425 | else { |
426 | $self->throw_error("Unable to canonicalize the 'handles' option with $handles"); |
427 | } |
428 | } |
429 | |
430 | sub _make_delegation_method { |
431 | my($self, $handle, $method_to_call) = @_; |
432 | my $delegator = $self->delegation_metaclass; |
433 | Mouse::Util::load_class($delegator); |
434 | |
435 | return $delegator->_generate_delegation($self, $handle, $method_to_call); |
436 | } |
437 | |
fce211ae |
438 | sub throw_error{ |
439 | my $self = shift; |
440 | |
441 | my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class'; |
442 | $metaclass->throw_error(@_, depth => 1); |
1bfebf5f |
443 | } |
444 | |
c3398f5b |
445 | 1; |
c3398f5b |
446 | __END__ |
447 | |
448 | =head1 NAME |
449 | |
bedd575c |
450 | Mouse::Meta::Attribute - The Mouse attribute metaclass |
c3398f5b |
451 | |
a25ca8d6 |
452 | =head1 VERSION |
453 | |
a4cbb3cb |
454 | This document describes Mouse version 0.44 |
a25ca8d6 |
455 | |
c3398f5b |
456 | =head1 METHODS |
457 | |
1820fffe |
458 | =head2 C<< new(%options) -> Mouse::Meta::Attribute >> |
c3398f5b |
459 | |
306290e8 |
460 | Instantiates a new Mouse::Meta::Attribute. Does nothing else. |
c3398f5b |
461 | |
1820fffe |
462 | It adds the following options to the constructor: |
c3398f5b |
463 | |
1820fffe |
464 | =over 4 |
c3398f5b |
465 | |
612d3e1a |
466 | =item C<< is => 'ro', 'rw', 'bare' >> |
c3398f5b |
467 | |
1820fffe |
468 | This provides a shorthand for specifying the C<reader>, C<writer>, or |
469 | C<accessor> names. If the attribute is read-only ('ro') then it will |
470 | have a C<reader> method with the same attribute as the name. |
c3398f5b |
471 | |
1820fffe |
472 | If it is read-write ('rw') then it will have an C<accessor> method |
473 | with the same name. If you provide an explicit C<writer> for a |
474 | read-write attribute, then you will have a C<reader> with the same |
475 | name as the attribute, and a C<writer> with the name you provided. |
c3398f5b |
476 | |
1820fffe |
477 | Use 'bare' when you are deliberately not installing any methods |
478 | (accessor, reader, etc.) associated with this attribute; otherwise, |
479 | Moose will issue a deprecation warning when this attribute is added to a |
480 | metaclass. |
c3398f5b |
481 | |
612d3e1a |
482 | =item C<< isa => Type >> |
ab27a55e |
483 | |
1820fffe |
484 | This option accepts a type. The type can be a string, which should be |
485 | a type name. If the type name is unknown, it is assumed to be a class |
486 | name. |
ab27a55e |
487 | |
1820fffe |
488 | This option can also accept a L<Moose::Meta::TypeConstraint> object. |
ab27a55e |
489 | |
1820fffe |
490 | If you I<also> provide a C<does> option, then your C<isa> option must |
491 | be a class name, and that class must do the role specified with |
492 | C<does>. |
ab27a55e |
493 | |
612d3e1a |
494 | =item C<< does => Role >> |
ab27a55e |
495 | |
1820fffe |
496 | This is short-hand for saying that the attribute's type must be an |
497 | object which does the named role. |
c3398f5b |
498 | |
1820fffe |
499 | B<This option is not yet supported.> |
c3398f5b |
500 | |
612d3e1a |
501 | =item C<< coerce => Bool >> |
ab27a55e |
502 | |
1820fffe |
503 | This option is only valid for objects with a type constraint |
504 | (C<isa>). If this is true, then coercions will be applied whenever |
505 | this attribute is set. |
c3398f5b |
506 | |
1820fffe |
507 | You can make both this and the C<weak_ref> option true. |
c3398f5b |
508 | |
612d3e1a |
509 | =item C<< trigger => CodeRef >> |
ab27a55e |
510 | |
1820fffe |
511 | This option accepts a subroutine reference, which will be called after |
512 | the attribute is set. |
ab27a55e |
513 | |
612d3e1a |
514 | =item C<< required => Bool >> |
ab27a55e |
515 | |
1820fffe |
516 | An attribute which is required must be provided to the constructor. An |
517 | attribute which is required can also have a C<default> or C<builder>, |
518 | which will satisfy its required-ness. |
ab27a55e |
519 | |
1820fffe |
520 | A required attribute must have a C<default>, C<builder> or a |
521 | non-C<undef> C<init_arg> |
ab27a55e |
522 | |
612d3e1a |
523 | =item C<< lazy => Bool >> |
ab27a55e |
524 | |
1820fffe |
525 | A lazy attribute must have a C<default> or C<builder>. When an |
526 | attribute is lazy, the default value will not be calculated until the |
527 | attribute is read. |
93f08899 |
528 | |
612d3e1a |
529 | =item C<< weak_ref => Bool >> |
0fff36e6 |
530 | |
1820fffe |
531 | If this is true, the attribute's value will be stored as a weak |
532 | reference. |
c3398f5b |
533 | |
612d3e1a |
534 | =item C<< auto_deref => Bool >> |
fb706f5c |
535 | |
1820fffe |
536 | If this is true, then the reader will dereference the value when it is |
537 | called. The attribute must have a type constraint which defines the |
538 | attribute as an array or hash reference. |
539 | |
612d3e1a |
540 | =item C<< lazy_build => Bool >> |
1820fffe |
541 | |
542 | Setting this to true makes the attribute lazy and provides a number of |
543 | default methods. |
fb706f5c |
544 | |
1820fffe |
545 | has 'size' => ( |
546 | is => 'ro', |
547 | lazy_build => 1, |
548 | ); |
93d190e0 |
549 | |
1820fffe |
550 | is equivalent to this: |
93d190e0 |
551 | |
1820fffe |
552 | has 'size' => ( |
553 | is => 'ro', |
554 | lazy => 1, |
555 | builder => '_build_size', |
556 | clearer => 'clear_size', |
557 | predicate => 'has_size', |
558 | ); |
93d190e0 |
559 | |
1820fffe |
560 | =back |
561 | |
e5e22afd |
562 | =head2 C<< associate_method(MethodName) >> |
31c5194b |
563 | |
564 | Associates a method with the attribute. Typically, this is called internally |
565 | when an attribute generates its accessors. |
566 | |
e5e22afd |
567 | Currently the argument I<MethodName> is ignored in Mouse. |
31c5194b |
568 | |
1820fffe |
569 | =head2 C<< verify_against_type_constraint(Item) -> TRUE | ERROR >> |
570 | |
571 | Checks that the given value passes this attribute's type constraint. Returns C<true> |
572 | on success, otherwise C<confess>es. |
93d190e0 |
573 | |
1820fffe |
574 | =head2 C<< clone_and_inherit_options(options) -> Mouse::Meta::Attribute >> |
f7b11a21 |
575 | |
612d3e1a |
576 | Creates a new attribute in the owner class, inheriting options from parent classes. |
f7b11a21 |
577 | Accessors and helper methods are installed. Some error checking is done. |
578 | |
9ae9702e |
579 | =head2 C<< get_read_method_ref >> |
580 | |
581 | =head2 C<< get_write_method_ref >> |
582 | |
583 | Returns the subroutine reference of a method suitable for reading or |
584 | writing the attribute's value in the associated class. These methods |
585 | always return a subroutine reference, regardless of whether or not the |
df77fd72 |
586 | attribute is read- or write-only. |
587 | |
1820fffe |
588 | =head1 SEE ALSO |
f7b11a21 |
589 | |
1820fffe |
590 | L<Moose::Meta::Attribute> |
f7b11a21 |
591 | |
31c5194b |
592 | L<Class::MOP::Attribute> |
593 | |
c3398f5b |
594 | =cut |
595 | |