Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
ba38bf08 |
7 | use Class::MOP::Method::Accessor; |
8 | |
2eb717d5 |
9 | use Carp 'confess'; |
9ec169fe |
10 | use Scalar::Util 'blessed', 'reftype', 'weaken'; |
2eb717d5 |
11 | |
232c4e13 |
12 | our $VERSION = '0.17'; |
f0480c45 |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
8b978dd5 |
14 | |
b1897d4d |
15 | use base 'Class::MOP::Object'; |
16 | |
1d68af04 |
17 | sub meta { |
727919c5 |
18 | require Class::MOP::Class; |
aa448b16 |
19 | Class::MOP::Class->initialize(blessed($_[0]) || $_[0]); |
727919c5 |
20 | } |
2eb717d5 |
21 | |
727919c5 |
22 | # NOTE: (meta-circularity) |
1d68af04 |
23 | # This method will be replaced in the |
24 | # boostrap section of Class::MOP, by |
25 | # a new version which uses the |
727919c5 |
26 | # &Class::MOP::Class::construct_instance |
27 | # method to build an attribute meta-object |
28 | # which itself is described with attribute |
1d68af04 |
29 | # meta-objects. |
727919c5 |
30 | # - Ain't meta-circularity grand? :) |
8b978dd5 |
31 | sub new { |
32 | my $class = shift; |
33 | my $name = shift; |
1d68af04 |
34 | my %options = @_; |
35 | |
cbd9f942 |
36 | (defined $name && $name) |
8b978dd5 |
37 | || confess "You must provide a name for the attribute"; |
1d68af04 |
38 | |
39 | $options{init_arg} = $name |
5659d76e |
40 | if not exists $options{init_arg}; |
1d68af04 |
41 | if(exists $options{builder}){ |
42 | confess("builder must be a defined scalar value which is a method name") |
43 | if ref $options{builder} || !(defined $options{builder}); |
44 | confess("Setting both default and builder is not allowed.") |
45 | if exists $options{default}; |
8fe581e5 |
46 | } else { |
47 | (is_default_a_coderef(\%options)) |
48 | || confess("References are not allowed as default values, you must ". |
49 | "wrap then in a CODE reference (ex: sub { [] } and not [])") |
50 | if exists $options{default} && ref $options{default}; |
1d68af04 |
51 | } |
8b978dd5 |
52 | bless { |
c23184fc |
53 | '$!name' => $name, |
54 | '$!accessor' => $options{accessor}, |
55 | '$!reader' => $options{reader}, |
56 | '$!writer' => $options{writer}, |
57 | '$!predicate' => $options{predicate}, |
58 | '$!clearer' => $options{clearer}, |
1d68af04 |
59 | '$!builder' => $options{builder}, |
c23184fc |
60 | '$!init_arg' => $options{init_arg}, |
61 | '$!default' => $options{default}, |
1d68af04 |
62 | # keep a weakened link to the |
9ec169fe |
63 | # class we are associated with |
c23184fc |
64 | '$!associated_class' => undef, |
1d68af04 |
65 | # and a list of the methods |
3545c727 |
66 | # associated with this attr |
c23184fc |
67 | '@!associated_methods' => [], |
8b978dd5 |
68 | } => $class; |
69 | } |
70 | |
7b31baf4 |
71 | # NOTE: |
1d68af04 |
72 | # this is a primative (and kludgy) clone operation |
16e960bd |
73 | # for now, it will be replaced in the Class::MOP |
1d68af04 |
74 | # bootstrap with a proper one, however we know |
5659d76e |
75 | # that this one will work fine for now. |
76 | sub clone { |
77 | my $self = shift; |
78 | my %options = @_; |
79 | (blessed($self)) |
80 | || confess "Can only clone an instance"; |
81 | return bless { %{$self}, %options } => blessed($self); |
82 | } |
83 | |
bd4e03f9 |
84 | sub initialize_instance_slot { |
f892c0f0 |
85 | my ($self, $meta_instance, $instance, $params) = @_; |
c23184fc |
86 | my $init_arg = $self->{'$!init_arg'}; |
bd4e03f9 |
87 | # try to fetch the init arg from the %params ... |
8d2d4c67 |
88 | |
1d68af04 |
89 | # if nothing was in the %params, we can use the |
bd4e03f9 |
90 | # attribute's default value (if it has one) |
8d2d4c67 |
91 | if(exists $params->{$init_arg}){ |
92 | $meta_instance->set_slot_value($instance, $self->name, $params->{$init_arg}); |
b7bdffc3 |
93 | } |
94 | elsif (defined $self->{'$!default'}) { |
8d2d4c67 |
95 | $meta_instance->set_slot_value($instance, $self->name, $self->default($instance)); |
b7bdffc3 |
96 | } |
97 | elsif (defined( my $builder = $self->{'$!builder'})) { |
98 | if ($builder = $instance->can($builder)) { |
8d2d4c67 |
99 | $meta_instance->set_slot_value($instance, $self->name, $instance->$builder); |
b7bdffc3 |
100 | } |
101 | else { |
232c4e13 |
102 | confess(blessed($instance)." does not support builder method '". $self->{'$!builder'} ."' for attribute '" . $self->name . "'"); |
8fe581e5 |
103 | } |
1d68af04 |
104 | } |
bd4e03f9 |
105 | } |
106 | |
5659d76e |
107 | # NOTE: |
1d68af04 |
108 | # the next bunch of methods will get bootstrapped |
7b31baf4 |
109 | # away in the Class::MOP bootstrapping section |
110 | |
c23184fc |
111 | sub name { $_[0]->{'$!name'} } |
c50c603e |
112 | |
c23184fc |
113 | sub associated_class { $_[0]->{'$!associated_class'} } |
114 | sub associated_methods { $_[0]->{'@!associated_methods'} } |
7b31baf4 |
115 | |
c23184fc |
116 | sub has_accessor { defined($_[0]->{'$!accessor'}) ? 1 : 0 } |
117 | sub has_reader { defined($_[0]->{'$!reader'}) ? 1 : 0 } |
118 | sub has_writer { defined($_[0]->{'$!writer'}) ? 1 : 0 } |
119 | sub has_predicate { defined($_[0]->{'$!predicate'}) ? 1 : 0 } |
120 | sub has_clearer { defined($_[0]->{'$!clearer'}) ? 1 : 0 } |
1d68af04 |
121 | sub has_builder { defined($_[0]->{'$!builder'}) ? 1 : 0 } |
c23184fc |
122 | sub has_init_arg { defined($_[0]->{'$!init_arg'}) ? 1 : 0 } |
123 | sub has_default { defined($_[0]->{'$!default'}) ? 1 : 0 } |
c50c603e |
124 | |
1d68af04 |
125 | sub accessor { $_[0]->{'$!accessor'} } |
c23184fc |
126 | sub reader { $_[0]->{'$!reader'} } |
127 | sub writer { $_[0]->{'$!writer'} } |
128 | sub predicate { $_[0]->{'$!predicate'} } |
129 | sub clearer { $_[0]->{'$!clearer'} } |
1d68af04 |
130 | sub builder { $_[0]->{'$!builder'} } |
c23184fc |
131 | sub init_arg { $_[0]->{'$!init_arg'} } |
c50c603e |
132 | |
7b31baf4 |
133 | # end bootstrapped away method section. |
134 | # (all methods below here are kept intact) |
135 | |
b25109b1 |
136 | sub get_read_method { $_[0]->reader || $_[0]->accessor } |
137 | sub get_write_method { $_[0]->writer || $_[0]->accessor } |
138 | |
1d68af04 |
139 | sub is_default_a_coderef { |
140 | ('CODE' eq (reftype($_[0]->{'$!default'} || $_[0]->{default}) || '')) |
c0cbf4d9 |
141 | } |
142 | |
1d68af04 |
143 | sub default { |
c0cbf4d9 |
144 | my ($self, $instance) = @_; |
9363ea89 |
145 | if (defined $instance && $self->is_default_a_coderef) { |
1d68af04 |
146 | # if the default is a CODE ref, then |
727919c5 |
147 | # we pass in the instance and default |
1d68af04 |
148 | # can return a value based on that |
727919c5 |
149 | # instance. Somewhat crude, but works. |
c23184fc |
150 | return $self->{'$!default'}->($instance); |
1d68af04 |
151 | } |
c23184fc |
152 | $self->{'$!default'}; |
c50c603e |
153 | } |
8b978dd5 |
154 | |
c57c8b10 |
155 | # slots |
156 | |
157 | sub slots { (shift)->name } |
158 | |
1d68af04 |
159 | # class association |
727919c5 |
160 | |
9ec169fe |
161 | sub attach_to_class { |
162 | my ($self, $class) = @_; |
163 | (blessed($class) && $class->isa('Class::MOP::Class')) |
164 | || confess "You must pass a Class::MOP::Class instance (or a subclass)"; |
1d68af04 |
165 | weaken($self->{'$!associated_class'} = $class); |
9ec169fe |
166 | } |
167 | |
168 | sub detach_from_class { |
169 | my $self = shift; |
1d68af04 |
170 | $self->{'$!associated_class'} = undef; |
9ec169fe |
171 | } |
172 | |
1d68af04 |
173 | # method association |
3545c727 |
174 | |
175 | sub associate_method { |
176 | my ($self, $method) = @_; |
c23184fc |
177 | push @{$self->{'@!associated_methods'}} => $method; |
3545c727 |
178 | } |
179 | |
16e960bd |
180 | ## Slot management |
181 | |
182 | sub set_value { |
1396f86b |
183 | my ($self, $instance, $value) = @_; |
16e960bd |
184 | |
3545c727 |
185 | Class::MOP::Class->initialize(blessed($instance)) |
16e960bd |
186 | ->get_meta_instance |
3545c727 |
187 | ->set_slot_value($instance, $self->name, $value); |
16e960bd |
188 | } |
189 | |
190 | sub get_value { |
1396f86b |
191 | my ($self, $instance) = @_; |
16e960bd |
192 | |
3545c727 |
193 | Class::MOP::Class->initialize(blessed($instance)) |
16e960bd |
194 | ->get_meta_instance |
1396f86b |
195 | ->get_slot_value($instance, $self->name); |
16e960bd |
196 | } |
197 | |
3545c727 |
198 | sub has_value { |
199 | my ($self, $instance) = @_; |
1d68af04 |
200 | |
8d2d4c67 |
201 | Class::MOP::Class->initialize(blessed($instance)) |
202 | ->get_meta_instance |
203 | ->is_slot_initialized($instance, $self->name); |
3545c727 |
204 | } |
205 | |
206 | sub clear_value { |
207 | my ($self, $instance) = @_; |
1d68af04 |
208 | |
3545c727 |
209 | Class::MOP::Class->initialize(blessed($instance)) |
210 | ->get_meta_instance |
1d68af04 |
211 | ->deinitialize_slot($instance, $self->name); |
3545c727 |
212 | } |
213 | |
ba38bf08 |
214 | ## load em up ... |
c0cbf4d9 |
215 | |
ba38bf08 |
216 | sub accessor_metaclass { 'Class::MOP::Method::Accessor' } |
c0cbf4d9 |
217 | |
9ec169fe |
218 | sub process_accessors { |
c0cbf4d9 |
219 | my ($self, $type, $accessor, $generate_as_inline_methods) = @_; |
013b1897 |
220 | if (reftype($accessor)) { |
221 | (reftype($accessor) eq 'HASH') |
7d28758b |
222 | || confess "bad accessor/reader/writer/predicate/clearer format, must be a HASH ref"; |
4d47b77f |
223 | my ($name, $method) = %{$accessor}; |
3545c727 |
224 | $method = $self->accessor_metaclass->wrap($method); |
225 | $self->associate_method($method); |
1d68af04 |
226 | return ($name, $method); |
2eb717d5 |
227 | } |
9ec169fe |
228 | else { |
1d68af04 |
229 | my $inline_me = ($generate_as_inline_methods && $self->associated_class->instance_metaclass->is_inlinable); |
ba38bf08 |
230 | my $method; |
231 | eval { |
232 | $method = $self->accessor_metaclass->new( |
233 | attribute => $self, |
d90b42a6 |
234 | is_inline => $inline_me, |
ba38bf08 |
235 | accessor_type => $type, |
1d68af04 |
236 | ); |
ba38bf08 |
237 | }; |
1d68af04 |
238 | confess "Could not create the '$type' method for " . $self->name . " because : $@" if $@; |
3545c727 |
239 | $self->associate_method($method); |
ba38bf08 |
240 | return ($accessor, $method); |
1d68af04 |
241 | } |
9ec169fe |
242 | } |
243 | |
244 | sub install_accessors { |
c0cbf4d9 |
245 | my $self = shift; |
246 | my $inline = shift; |
247 | my $class = $self->associated_class; |
1d68af04 |
248 | |
9ec169fe |
249 | $class->add_method( |
c0cbf4d9 |
250 | $self->process_accessors('accessor' => $self->accessor(), $inline) |
9ec169fe |
251 | ) if $self->has_accessor(); |
252 | |
1d68af04 |
253 | $class->add_method( |
c0cbf4d9 |
254 | $self->process_accessors('reader' => $self->reader(), $inline) |
9ec169fe |
255 | ) if $self->has_reader(); |
256 | |
257 | $class->add_method( |
c0cbf4d9 |
258 | $self->process_accessors('writer' => $self->writer(), $inline) |
9ec169fe |
259 | ) if $self->has_writer(); |
260 | |
261 | $class->add_method( |
c0cbf4d9 |
262 | $self->process_accessors('predicate' => $self->predicate(), $inline) |
9ec169fe |
263 | ) if $self->has_predicate(); |
1d68af04 |
264 | |
7d28758b |
265 | $class->add_method( |
266 | $self->process_accessors('clearer' => $self->clearer(), $inline) |
267 | ) if $self->has_clearer(); |
1d68af04 |
268 | |
9ec169fe |
269 | return; |
2eb717d5 |
270 | } |
271 | |
b51af7f9 |
272 | { |
273 | my $_remove_accessor = sub { |
274 | my ($accessor, $class) = @_; |
c50c603e |
275 | if (reftype($accessor) && reftype($accessor) eq 'HASH') { |
276 | ($accessor) = keys %{$accessor}; |
1d68af04 |
277 | } |
278 | my $method = $class->get_method($accessor); |
279 | $class->remove_method($accessor) |
ba38bf08 |
280 | if (blessed($method) && $method->isa('Class::MOP::Method::Accessor')); |
b51af7f9 |
281 | }; |
1d68af04 |
282 | |
b51af7f9 |
283 | sub remove_accessors { |
9ec169fe |
284 | my $self = shift; |
2367814a |
285 | # TODO: |
1d68af04 |
286 | # we really need to make sure to remove from the |
287 | # associates methods here as well. But this is |
288 | # such a slimly used method, I am not worried |
2367814a |
289 | # about it right now. |
9ec169fe |
290 | $_remove_accessor->($self->accessor(), $self->associated_class()) if $self->has_accessor(); |
291 | $_remove_accessor->($self->reader(), $self->associated_class()) if $self->has_reader(); |
292 | $_remove_accessor->($self->writer(), $self->associated_class()) if $self->has_writer(); |
293 | $_remove_accessor->($self->predicate(), $self->associated_class()) if $self->has_predicate(); |
7d28758b |
294 | $_remove_accessor->($self->clearer(), $self->associated_class()) if $self->has_clearer(); |
1d68af04 |
295 | return; |
b51af7f9 |
296 | } |
297 | |
8b978dd5 |
298 | } |
299 | |
300 | 1; |
301 | |
302 | __END__ |
303 | |
304 | =pod |
305 | |
1d68af04 |
306 | =head1 NAME |
8b978dd5 |
307 | |
308 | Class::MOP::Attribute - Attribute Meta Object |
309 | |
310 | =head1 SYNOPSIS |
1d68af04 |
311 | |
8b978dd5 |
312 | Class::MOP::Attribute->new('$foo' => ( |
fe122940 |
313 | accessor => 'foo', # dual purpose get/set accessor |
1d68af04 |
314 | predicate => 'has_foo' # predicate check for defined-ness |
fe122940 |
315 | init_arg => '-foo', # class->new will look for a -foo key |
316 | default => 'BAR IS BAZ!' # if no -foo key is provided, use this |
8b978dd5 |
317 | )); |
1d68af04 |
318 | |
8b978dd5 |
319 | Class::MOP::Attribute->new('$.bar' => ( |
fe122940 |
320 | reader => 'bar', # getter |
1d68af04 |
321 | writer => 'set_bar', # setter |
322 | predicate => 'has_bar' # predicate check for defined-ness |
fe122940 |
323 | init_arg => ':bar', # class->new will look for a :bar key |
8b978dd5 |
324 | # no default value means it is undef |
325 | )); |
326 | |
327 | =head1 DESCRIPTION |
328 | |
fe122940 |
329 | The Attribute Protocol is almost entirely an invention of this module, |
1d68af04 |
330 | and is completely optional to this MOP. This is because Perl 5 does not |
331 | have consistent notion of what is an attribute of a class. There are |
332 | so many ways in which this is done, and very few (if any) are |
fe122940 |
333 | easily discoverable by this module. |
552e3d24 |
334 | |
1d68af04 |
335 | So, all that said, this module attempts to inject some order into this |
336 | chaos, by introducing a consistent API which can be used to create |
fe122940 |
337 | object attributes. |
552e3d24 |
338 | |
339 | =head1 METHODS |
340 | |
341 | =head2 Creation |
342 | |
343 | =over 4 |
344 | |
fe122940 |
345 | =item B<new ($name, ?%options)> |
346 | |
1d68af04 |
347 | An attribute must (at the very least), have a C<$name>. All other |
a2e85e6c |
348 | C<%options> are contained added as key-value pairs. Acceptable keys |
fe122940 |
349 | are as follows: |
350 | |
351 | =over 4 |
352 | |
353 | =item I<init_arg> |
354 | |
1d68af04 |
355 | This should be a string value representing the expected key in |
356 | an initialization hash. For instance, if we have an I<init_arg> |
fe122940 |
357 | value of C<-foo>, then the following code will Just Work. |
358 | |
359 | MyClass->meta->construct_instance(-foo => "Hello There"); |
360 | |
1d68af04 |
361 | In an init_arg is not assigned, it will automatically use the |
7b31baf4 |
362 | value of C<$name>. |
363 | |
fe122940 |
364 | =item I<default> |
365 | |
1d68af04 |
366 | The value of this key is the default value which |
367 | C<Class::MOP::Class::construct_instance> will initialize the |
368 | attribute to. |
369 | |
370 | =item I<builder> |
371 | |
372 | The value of this key is the name of the method that will be |
373 | called to obtain the value used to initialize the attribute. |
374 | This should be a method in the class associated with the attribute, |
375 | not a method in the attribute class itself. |
fe122940 |
376 | |
377 | B<NOTE:> |
1d68af04 |
378 | If the value is a simple scalar (string or number), then it can |
379 | be just passed as is. However, if you wish to initialize it with |
380 | a HASH or ARRAY ref, then you need to wrap that inside a CODE |
fe122940 |
381 | reference, like so: |
382 | |
383 | Class::MOP::Attribute->new('@foo' => ( |
384 | default => sub { [] }, |
385 | )); |
1d68af04 |
386 | |
387 | # or ... |
388 | |
fe122940 |
389 | Class::MOP::Attribute->new('%foo' => ( |
390 | default => sub { {} }, |
1d68af04 |
391 | )); |
fe122940 |
392 | |
1d68af04 |
393 | If you wish to initialize an attribute with a CODE reference |
fe122940 |
394 | itself, then you need to wrap that in a subroutine as well, like |
395 | so: |
1d68af04 |
396 | |
fe122940 |
397 | Class::MOP::Attribute->new('&foo' => ( |
398 | default => sub { sub { print "Hello World" } }, |
399 | )); |
400 | |
1d68af04 |
401 | And lastly, if the value of your attribute is dependent upon |
402 | some other aspect of the instance structure, then you can take |
403 | advantage of the fact that when the I<default> value is a CODE |
404 | reference, it is passed the raw (unblessed) instance structure |
fe122940 |
405 | as it's only argument. So you can do things like this: |
406 | |
407 | Class::MOP::Attribute->new('$object_identity' => ( |
408 | default => sub { Scalar::Util::refaddr($_[0]) }, |
409 | )); |
410 | |
1d68af04 |
411 | This last feature is fairly limited as there is no gurantee of |
412 | the order of attribute initializations, so you cannot perform |
413 | any kind of dependent initializations. However, if this is |
414 | something you need, you could subclass B<Class::MOP::Class> and |
415 | this class to acheive it. However, this is currently left as |
fe122940 |
416 | an exercise to the reader :). |
417 | |
418 | =back |
419 | |
7d28758b |
420 | The I<accessor>, I<reader>, I<writer>, I<predicate> and I<clearer> keys can |
421 | contain either; the name of the method and an appropriate default one will be |
422 | generated for you, B<or> a HASH ref containing exactly one key (which will be |
423 | used as the name of the method) and one value, which should contain a CODE |
424 | reference which will be installed as the method itself. |
59e7697f |
425 | |
426 | =over 4 |
427 | |
428 | =item I<accessor> |
429 | |
1d68af04 |
430 | The I<accessor> is a standard perl-style read/write accessor. It will |
431 | return the value of the attribute, and if a value is passed as an argument, |
fe122940 |
432 | it will assign that value to the attribute. |
433 | |
434 | B<NOTE:> |
1d68af04 |
435 | This method will properly handle the following code, by assigning an |
fe122940 |
436 | C<undef> value to the attribute. |
437 | |
438 | $object->set_something(undef); |
439 | |
59e7697f |
440 | =item I<reader> |
441 | |
1d68af04 |
442 | This is a basic read-only accessor, it will just return the value of |
fe122940 |
443 | the attribute. |
444 | |
59e7697f |
445 | =item I<writer> |
446 | |
1d68af04 |
447 | This is a basic write accessor, it accepts a single argument, and |
448 | assigns that value to the attribute. This method does not intentially |
449 | return a value, however perl will return the result of the last |
450 | expression in the subroutine, which returns in this returning the |
451 | same value that it was passed. |
59e7697f |
452 | |
fe122940 |
453 | B<NOTE:> |
1d68af04 |
454 | This method will properly handle the following code, by assigning an |
fe122940 |
455 | C<undef> value to the attribute. |
59e7697f |
456 | |
fe122940 |
457 | $object->set_something(); |
458 | |
459 | =item I<predicate> |
460 | |
1d68af04 |
461 | This is a basic test to see if the value of the attribute is not |
462 | C<undef>. It will return true (C<1>) if the attribute's value is |
fe122940 |
463 | defined, and false (C<0>) otherwise. |
59e7697f |
464 | |
7d28758b |
465 | =item I<clearer> |
466 | |
467 | This is the a method that will uninitialize the attr, reverting lazy values |
468 | back to their "unfulfilled" state. |
469 | |
59e7697f |
470 | =back |
552e3d24 |
471 | |
bd4e03f9 |
472 | =item B<clone (%options)> |
473 | |
474 | =item B<initialize_instance_slot ($instance, $params)> |
475 | |
1d68af04 |
476 | =back |
552e3d24 |
477 | |
16e960bd |
478 | =head2 Value management |
479 | |
1d68af04 |
480 | These methods are basically "backdoors" to the instance, which can be used |
481 | to bypass the regular accessors, but still stay within the context of the MOP. |
2367814a |
482 | |
1d68af04 |
483 | These methods are not for general use, and should only be used if you really |
2367814a |
484 | know what you are doing. |
485 | |
16e960bd |
486 | =over 4 |
487 | |
3545c727 |
488 | =item B<set_value ($instance, $value)> |
16e960bd |
489 | |
490 | Set the value without going through the accessor. Note that this may be done to |
491 | even attributes with just read only accessors. |
492 | |
3545c727 |
493 | =item B<get_value ($instance)> |
16e960bd |
494 | |
495 | Return the value without going through the accessor. Note that this may be done |
496 | even to attributes with just write only accessors. |
497 | |
3545c727 |
498 | =item B<has_value ($instance)> |
499 | |
1d68af04 |
500 | Returns a boolean indicating if the item in the C<$instance> has a value in it. |
2367814a |
501 | This is basically what the default C<predicate> method calls. |
502 | |
3545c727 |
503 | =item B<clear_value ($instance)> |
504 | |
2367814a |
505 | This will clear the value in the C<$instance>. This is basically what the default |
1d68af04 |
506 | C<clearer> would call. Note that this may be done even if the attirbute does not |
2367814a |
507 | have any associated read, write or clear methods. |
508 | |
16e960bd |
509 | =back |
510 | |
552e3d24 |
511 | =head2 Informational |
512 | |
1d68af04 |
513 | These are all basic read-only value accessors for the values |
fe122940 |
514 | passed into C<new>. I think they are pretty much self-explanitory. |
515 | |
552e3d24 |
516 | =over 4 |
517 | |
518 | =item B<name> |
519 | |
520 | =item B<accessor> |
521 | |
522 | =item B<reader> |
523 | |
524 | =item B<writer> |
525 | |
c50c603e |
526 | =item B<predicate> |
527 | |
7d28758b |
528 | =item B<clearer> |
529 | |
552e3d24 |
530 | =item B<init_arg> |
531 | |
495af518 |
532 | =item B<is_default_a_coderef> |
533 | |
fe122940 |
534 | =item B<default (?$instance)> |
535 | |
1d68af04 |
536 | As noted in the documentation for C<new> above, if the I<default> |
fe122940 |
537 | value is a CODE reference, this accessor will pass a single additional |
538 | argument C<$instance> into it and return the value. |
552e3d24 |
539 | |
c57c8b10 |
540 | =item B<slots> |
541 | |
1d68af04 |
542 | Returns a list of slots required by the attribute. This is usually |
c57c8b10 |
543 | just one, which is the name of the attribute. |
544 | |
b25109b1 |
545 | =item B<get_read_method> |
546 | |
547 | =item B<get_write_method> |
548 | |
549 | Return the name of a method suitable for reading / writing the value of the |
550 | attribute in the associated class. Suitable for use whether C<reader> and |
551 | C<writer> or C<accessor> was used. |
552 | |
552e3d24 |
553 | =back |
554 | |
555 | =head2 Informational predicates |
556 | |
a2e85e6c |
557 | These are all basic predicate methods for the values passed into C<new>. |
fe122940 |
558 | |
552e3d24 |
559 | =over 4 |
560 | |
561 | =item B<has_accessor> |
562 | |
552e3d24 |
563 | =item B<has_reader> |
564 | |
552e3d24 |
565 | =item B<has_writer> |
566 | |
c50c603e |
567 | =item B<has_predicate> |
568 | |
7d28758b |
569 | =item B<has_clearer> |
570 | |
552e3d24 |
571 | =item B<has_init_arg> |
572 | |
552e3d24 |
573 | =item B<has_default> |
574 | |
bf731086 |
575 | =item B<has_builder> |
576 | |
552e3d24 |
577 | =back |
578 | |
9ec169fe |
579 | =head2 Class association |
580 | |
1d68af04 |
581 | These methods allow you to manage the attributes association with |
582 | the class that contains it. These methods should not be used |
2367814a |
583 | lightly, nor are they very magical, they are mostly used internally |
584 | and by metaclass instances. |
585 | |
9ec169fe |
586 | =over 4 |
587 | |
588 | =item B<associated_class> |
589 | |
2367814a |
590 | This returns the metaclass this attribute is associated with. |
591 | |
9ec169fe |
592 | =item B<attach_to_class ($class)> |
593 | |
1d68af04 |
594 | This will store a weaken reference to C<$class> internally. You should |
2367814a |
595 | note that just changing the class assocation will not remove the attribute |
596 | from it's old class, and initialize it (and it's accessors) in the new |
597 | C<$class>. It is up to you to do this manually. |
598 | |
9ec169fe |
599 | =item B<detach_from_class> |
600 | |
1d68af04 |
601 | This will remove the weakened reference to the class. It does B<not> |
602 | remove the attribute itself from the class (or remove it's accessors), |
603 | you must do that yourself if you want too. Actually if that is what |
604 | you want to do, you should probably be looking at |
2367814a |
605 | L<Class::MOP::Class::remove_attribute> instead. |
606 | |
9ec169fe |
607 | =back |
608 | |
552e3d24 |
609 | =head2 Attribute Accessor generation |
610 | |
611 | =over 4 |
612 | |
ba38bf08 |
613 | =item B<accessor_metaclass> |
614 | |
2367814a |
615 | Accessors are generated by an accessor metaclass, which is usually |
1d68af04 |
616 | a subclass of C<Class::MOP::Method::Accessor>. This method returns |
2367814a |
617 | the name of the accessor metaclass that this attribute uses. |
618 | |
619 | =item B<associate_method ($method)> |
620 | |
1d68af04 |
621 | This will associate a C<$method> with the given attribute which is |
622 | used internally by the accessor generator. |
3545c727 |
623 | |
624 | =item B<associated_methods> |
625 | |
1d68af04 |
626 | This will return the list of methods which have been associated with |
627 | the C<associate_method> methods. |
2367814a |
628 | |
9ec169fe |
629 | =item B<install_accessors> |
2eb717d5 |
630 | |
1d68af04 |
631 | This allows the attribute to generate and install code for it's own |
632 | I<accessor/reader/writer/predicate> methods. This is called by |
fe122940 |
633 | C<Class::MOP::Class::add_attribute>. |
2eb717d5 |
634 | |
1d68af04 |
635 | This method will call C<process_accessors> for each of the possible |
9ec169fe |
636 | method types (accessor, reader, writer & predicate). |
637 | |
638 | =item B<process_accessors ($type, $value)> |
639 | |
1d68af04 |
640 | This takes a C<$type> (accessor, reader, writer or predicate), and |
9ec169fe |
641 | a C<$value> (the value passed into the constructor for each of the |
1d68af04 |
642 | different types). It will then either generate the method itself |
643 | (using the C<generate_*_method> methods listed below) or it will |
644 | use the custom method passed through the constructor. |
9ec169fe |
645 | |
9ec169fe |
646 | =item B<remove_accessors> |
2eb717d5 |
647 | |
1d68af04 |
648 | This allows the attribute to remove the method for it's own |
649 | I<accessor/reader/writer/predicate/clearer>. This is called by |
fe122940 |
650 | C<Class::MOP::Class::remove_attribute>. |
2eb717d5 |
651 | |
1d68af04 |
652 | NOTE: This does not currently remove methods from the list returned |
2367814a |
653 | by C<associated_methods>, that is on the TODO list. |
654 | |
2eb717d5 |
655 | =back |
656 | |
657 | =head2 Introspection |
658 | |
659 | =over 4 |
552e3d24 |
660 | |
2eb717d5 |
661 | =item B<meta> |
552e3d24 |
662 | |
1d68af04 |
663 | This will return a B<Class::MOP::Class> instance which is related |
fe122940 |
664 | to this class. |
665 | |
1d68af04 |
666 | It should also be noted that B<Class::MOP> will actually bootstrap |
667 | this module by installing a number of attribute meta-objects into |
668 | it's metaclass. This will allow this class to reap all the benifits |
669 | of the MOP when subclassing it. |
fe122940 |
670 | |
552e3d24 |
671 | =back |
672 | |
1a09d9cc |
673 | =head1 AUTHORS |
8b978dd5 |
674 | |
a2e85e6c |
675 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
676 | |
677 | =head1 COPYRIGHT AND LICENSE |
678 | |
2367814a |
679 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
8b978dd5 |
680 | |
681 | L<http://www.iinteractive.com> |
682 | |
683 | This library is free software; you can redistribute it and/or modify |
1d68af04 |
684 | it under the same terms as Perl itself. |
8b978dd5 |
685 | |
16e960bd |
686 | =cut |
687 | |
7d28758b |
688 | |