Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Class; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
c23184fc |
7 | use Class::MOP::Immutable; |
ba38bf08 |
8 | use Class::MOP::Instance; |
9 | use Class::MOP::Method::Wrapped; |
10 | |
8b978dd5 |
11 | use Carp 'confess'; |
9b522fc4 |
12 | use Scalar::Util 'blessed', 'weaken'; |
8b978dd5 |
13 | |
2e5c1a3f |
14 | our $VERSION = '0.65'; |
f0480c45 |
15 | our $AUTHORITY = 'cpan:STEVAN'; |
8b978dd5 |
16 | |
2243a22b |
17 | use base 'Class::MOP::Module'; |
18 | |
8b978dd5 |
19 | # Creation |
0ac992ee |
20 | |
be7677c7 |
21 | sub initialize { |
22 | my $class = shift; |
23 | my $package_name = shift; |
24 | (defined $package_name && $package_name && !blessed($package_name)) |
0ac992ee |
25 | || confess "You must pass a package name and it cannot be blessed"; |
408ce4ea |
26 | return Class::MOP::get_metaclass_by_name($package_name) |
27 | || $class->construct_class_instance('package' => $package_name, @_); |
be7677c7 |
28 | } |
29 | |
30 | sub reinitialize { |
31 | my $class = shift; |
32 | my $package_name = shift; |
33 | (defined $package_name && $package_name && !blessed($package_name)) |
0ac992ee |
34 | || confess "You must pass a package name and it cannot be blessed"; |
be7677c7 |
35 | Class::MOP::remove_metaclass_by_name($package_name); |
c23184fc |
36 | $class->construct_class_instance('package' => $package_name, @_); |
0ac992ee |
37 | } |
38 | |
39 | # NOTE: (meta-circularity) |
40 | # this is a special form of &construct_instance |
be7677c7 |
41 | # (see below), which is used to construct class |
0ac992ee |
42 | # meta-object instances for any Class::MOP::* |
43 | # class. All other classes will use the more |
be7677c7 |
44 | # normal &construct_instance. |
45 | sub construct_class_instance { |
46 | my $class = shift; |
47 | my %options = @_; |
c23184fc |
48 | my $package_name = $options{'package'}; |
be7677c7 |
49 | (defined $package_name && $package_name) |
0ac992ee |
50 | || confess "You must pass a package name"; |
be7677c7 |
51 | # NOTE: |
0ac992ee |
52 | # return the metaclass if we have it cached, |
53 | # and it is still defined (it has not been |
54 | # reaped by DESTROY yet, which can happen |
be7677c7 |
55 | # annoyingly enough during global destruction) |
3af3cbbd |
56 | |
57 | if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) { |
58 | return $meta; |
59 | } |
be7677c7 |
60 | |
61 | # NOTE: |
0ac992ee |
62 | # we need to deal with the possibility |
63 | # of class immutability here, and then |
be7677c7 |
64 | # get the name of the class appropriately |
65 | $class = (blessed($class) |
66 | ? ($class->is_immutable |
67 | ? $class->get_mutable_metaclass_name() |
68 | : blessed($class)) |
69 | : $class); |
70 | |
be7677c7 |
71 | # now create the metaclass |
72 | my $meta; |
9c6877f4 |
73 | if ($class eq 'Class::MOP::Class') { |
0ac992ee |
74 | no strict 'refs'; |
75 | $meta = bless { |
be7677c7 |
76 | # inherited from Class::MOP::Package |
0ac992ee |
77 | '$!package' => $package_name, |
78 | |
c4260b45 |
79 | # NOTE: |
0ac992ee |
80 | # since the following attributes will |
81 | # actually be loaded from the symbol |
c4260b45 |
82 | # table, and actually bypass the instance |
83 | # entirely, we can just leave these things |
84 | # listed here for reference, because they |
0ac992ee |
85 | # should not actually have a value associated |
c4260b45 |
86 | # with the slot. |
0ac992ee |
87 | '%!namespace' => \undef, |
be7677c7 |
88 | # inherited from Class::MOP::Module |
c23184fc |
89 | '$!version' => \undef, |
90 | '$!authority' => \undef, |
c4260b45 |
91 | # defined in Class::MOP::Class |
c23184fc |
92 | '@!superclasses' => \undef, |
0ac992ee |
93 | |
c23184fc |
94 | '%!methods' => {}, |
0ac992ee |
95 | '%!attributes' => {}, |
c23184fc |
96 | '$!attribute_metaclass' => $options{'attribute_metaclass'} || 'Class::MOP::Attribute', |
97 | '$!method_metaclass' => $options{'method_metaclass'} || 'Class::MOP::Method', |
98 | '$!instance_metaclass' => $options{'instance_metaclass'} || 'Class::MOP::Instance', |
e0e4674a |
99 | |
100 | ## uber-private variables |
101 | # NOTE: |
102 | # this starts out as undef so that |
103 | # we can tell the first time the |
104 | # methods are fetched |
105 | # - SL |
9b522fc4 |
106 | '$!_package_cache_flag' => undef, |
107 | '$!_meta_instance' => undef, |
be7677c7 |
108 | } => $class; |
109 | } |
110 | else { |
111 | # NOTE: |
112 | # it is safe to use meta here because |
0ac992ee |
113 | # class will always be a subclass of |
be7677c7 |
114 | # Class::MOP::Class, which defines meta |
115 | $meta = $class->meta->construct_instance(%options) |
727919c5 |
116 | } |
0ac992ee |
117 | |
be7677c7 |
118 | # and check the metaclass compatibility |
715adbb7 |
119 | $meta->check_metaclass_compatability(); |
0ac992ee |
120 | |
be7677c7 |
121 | Class::MOP::store_metaclass_by_name($package_name, $meta); |
0ac992ee |
122 | |
be7677c7 |
123 | # NOTE: |
124 | # we need to weaken any anon classes |
125 | # so that they can call DESTROY properly |
b9d9fc0b |
126 | Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class; |
0ac992ee |
127 | |
128 | $meta; |
129 | } |
130 | |
715adbb7 |
131 | sub reset_package_cache_flag { (shift)->{'$!_package_cache_flag'} = undef } |
132 | sub update_package_cache_flag { |
b1f5f41d |
133 | my $self = shift; |
e0e4674a |
134 | # NOTE: |
135 | # we can manually update the cache number |
136 | # since we are actually adding the method |
137 | # to our cache as well. This avoids us |
138 | # having to regenerate the method_map. |
139 | # - SL |
b1f5f41d |
140 | $self->{'$!_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name); |
e0e4674a |
141 | } |
142 | |
be7677c7 |
143 | sub check_metaclass_compatability { |
144 | my $self = shift; |
145 | |
146 | # this is always okay ... |
0ac992ee |
147 | return if blessed($self) eq 'Class::MOP::Class' && |
be7677c7 |
148 | $self->instance_metaclass eq 'Class::MOP::Instance'; |
149 | |
b7bdffc3 |
150 | my @class_list = $self->linearized_isa; |
be7677c7 |
151 | shift @class_list; # shift off $self->name |
373a16ae |
152 | |
0ac992ee |
153 | foreach my $class_name (@class_list) { |
be7677c7 |
154 | my $meta = Class::MOP::get_metaclass_by_name($class_name) || next; |
0ac992ee |
155 | |
373a16ae |
156 | # NOTE: |
0ac992ee |
157 | # we need to deal with the possibility |
158 | # of class immutability here, and then |
159 | # get the name of the class appropriately |
be7677c7 |
160 | my $meta_type = ($meta->is_immutable |
161 | ? $meta->get_mutable_metaclass_name() |
0ac992ee |
162 | : blessed($meta)); |
163 | |
be7677c7 |
164 | ($self->isa($meta_type)) |
408ce4ea |
165 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
0ac992ee |
166 | " is not compatible with the " . |
be7677c7 |
167 | $class_name . "->meta => (" . ($meta_type) . ")"; |
77e5fce4 |
168 | # NOTE: |
be7677c7 |
169 | # we also need to check that instance metaclasses |
170 | # are compatabile in the same the class. |
171 | ($self->instance_metaclass->isa($meta->instance_metaclass)) |
408ce4ea |
172 | || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . |
0ac992ee |
173 | " is not compatible with the " . |
174 | $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; |
175 | } |
176 | } |
8b978dd5 |
177 | |
6d5355c3 |
178 | ## ANON classes |
179 | |
180 | { |
181 | # NOTE: |
0ac992ee |
182 | # this should be sufficient, if you have a |
183 | # use case where it is not, write a test and |
6d5355c3 |
184 | # I will change it. |
185 | my $ANON_CLASS_SERIAL = 0; |
0ac992ee |
186 | |
b9d9fc0b |
187 | # NOTE: |
188 | # we need a sufficiently annoying prefix |
0ac992ee |
189 | # this should suffice for now, this is |
190 | # used in a couple of places below, so |
b9d9fc0b |
191 | # need to put it up here for now. |
0ac992ee |
192 | my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; |
b9d9fc0b |
193 | |
194 | sub is_anon_class { |
195 | my $self = shift; |
a651e249 |
196 | no warnings 'uninitialized'; |
0ac992ee |
197 | $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0; |
b9d9fc0b |
198 | } |
6d5355c3 |
199 | |
200 | sub create_anon_class { |
0ac992ee |
201 | my ($class, %options) = @_; |
6d5355c3 |
202 | my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL; |
88dd563c |
203 | return $class->create($package_name, %options); |
0ac992ee |
204 | } |
6d5355c3 |
205 | |
b9d9fc0b |
206 | # NOTE: |
0ac992ee |
207 | # this will only get called for |
208 | # anon-classes, all other calls |
209 | # are assumed to occur during |
b9d9fc0b |
210 | # global destruction and so don't |
211 | # really need to be handled explicitly |
212 | sub DESTROY { |
213 | my $self = shift; |
0ac992ee |
214 | no warnings 'uninitialized'; |
408ce4ea |
215 | return unless $self->name =~ /^$ANON_CLASS_PREFIX/; |
216 | my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/); |
0ac992ee |
217 | no strict 'refs'; |
b9d9fc0b |
218 | foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) { |
219 | delete ${$ANON_CLASS_PREFIX . $serial_id}{$key}; |
220 | } |
0ac992ee |
221 | delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; |
6d5355c3 |
222 | } |
b9d9fc0b |
223 | |
6d5355c3 |
224 | } |
225 | |
226 | # creating classes with MOP ... |
227 | |
8b978dd5 |
228 | sub create { |
88dd563c |
229 | my $class = shift; |
230 | my $package_name = shift; |
0ac992ee |
231 | |
bfe4d0fc |
232 | (defined $package_name && $package_name) |
8b978dd5 |
233 | || confess "You must pass a package name"; |
88dd563c |
234 | |
235 | (scalar @_ % 2 == 0) |
0ac992ee |
236 | || confess "You much pass all parameters as name => value pairs " . |
88dd563c |
237 | "(I found an uneven number of params in \@_)"; |
238 | |
239 | my (%options) = @_; |
d7b2249e |
240 | |
241 | (ref $options{superclasses} eq 'ARRAY') |
242 | || confess "You must pass an ARRAY ref of superclasses" |
243 | if exists $options{superclasses}; |
244 | |
245 | (ref $options{attributes} eq 'ARRAY') |
246 | || confess "You must pass an ARRAY ref of attributes" |
247 | if exists $options{attributes}; |
248 | |
249 | (ref $options{methods} eq 'HASH') |
250 | || confess "You must pass an HASH ref of methods" |
251 | if exists $options{methods}; |
0ac992ee |
252 | |
8b978dd5 |
253 | my $code = "package $package_name;"; |
0ac992ee |
254 | $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';" |
88dd563c |
255 | if exists $options{version}; |
0ac992ee |
256 | $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';" |
257 | if exists $options{authority}; |
258 | |
8b978dd5 |
259 | eval $code; |
0ac992ee |
260 | confess "creation of $package_name failed : $@" if $@; |
261 | |
bfe4d0fc |
262 | my $meta = $class->initialize($package_name); |
0ac992ee |
263 | |
264 | $meta->add_method('meta' => sub { |
df7b4119 |
265 | $class->initialize(blessed($_[0]) || $_[0]); |
aa448b16 |
266 | }); |
0ac992ee |
267 | |
8b978dd5 |
268 | $meta->superclasses(@{$options{superclasses}}) |
269 | if exists $options{superclasses}; |
2eb717d5 |
270 | # NOTE: |
0ac992ee |
271 | # process attributes first, so that they can |
2eb717d5 |
272 | # install accessors, but locally defined methods |
273 | # can then overwrite them. It is maybe a little odd, but |
274 | # I think this should be the order of things. |
275 | if (exists $options{attributes}) { |
cbd9f942 |
276 | foreach my $attr (@{$options{attributes}}) { |
277 | $meta->add_attribute($attr); |
2eb717d5 |
278 | } |
0ac992ee |
279 | } |
bfe4d0fc |
280 | if (exists $options{methods}) { |
281 | foreach my $method_name (keys %{$options{methods}}) { |
282 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
283 | } |
0ac992ee |
284 | } |
8b978dd5 |
285 | return $meta; |
286 | } |
287 | |
7b31baf4 |
288 | ## Attribute readers |
289 | |
290 | # NOTE: |
0ac992ee |
291 | # all these attribute readers will be bootstrapped |
7b31baf4 |
292 | # away in the Class::MOP bootstrap section |
293 | |
c23184fc |
294 | sub get_attribute_map { $_[0]->{'%!attributes'} } |
295 | sub attribute_metaclass { $_[0]->{'$!attribute_metaclass'} } |
296 | sub method_metaclass { $_[0]->{'$!method_metaclass'} } |
297 | sub instance_metaclass { $_[0]->{'$!instance_metaclass'} } |
7b31baf4 |
298 | |
0f71bc80 |
299 | # FIXME: |
300 | # this is a prime canidate for conversion to XS |
0ac992ee |
301 | sub get_method_map { |
c4260b45 |
302 | my $self = shift; |
e0e4674a |
303 | |
304 | if (defined $self->{'$!_package_cache_flag'} && |
b1f5f41d |
305 | $self->{'$!_package_cache_flag'} == Class::MOP::check_package_cache_flag($self->name)) { |
e0e4674a |
306 | return $self->{'%!methods'}; |
307 | } |
308 | |
0ac992ee |
309 | my $map = $self->{'%!methods'}; |
310 | |
0f71bc80 |
311 | my $class_name = $self->name; |
312 | my $method_metaclass = $self->method_metaclass; |
0ac992ee |
313 | |
ae234dc6 |
314 | my %all_code = $self->get_all_package_symbols('CODE'); |
315 | |
316 | foreach my $symbol (keys %all_code) { |
317 | my $code = $all_code{$symbol}; |
0ac992ee |
318 | |
319 | next if exists $map->{$symbol} && |
320 | defined $map->{$symbol} && |
321 | $map->{$symbol}->body == $code; |
322 | |
e0e4674a |
323 | my ($pkg, $name) = Class::MOP::get_code_info($code); |
46b23b44 |
324 | |
d7d3f3cb |
325 | # NOTE: |
326 | # in 5.10 constant.pm the constants show up |
327 | # as being in the right package, but in pre-5.10 |
328 | # they show up as constant::__ANON__ so we |
329 | # make an exception here to be sure that things |
330 | # work as expected in both. |
331 | # - SL |
332 | unless ($pkg eq 'constant' && $name eq '__ANON__') { |
333 | next if ($pkg || '') ne $class_name || |
334 | (($name || '') ne '__ANON__' && ($pkg || '') ne $class_name); |
335 | } |
46b23b44 |
336 | |
b38f3848 |
337 | $map->{$symbol} = $method_metaclass->wrap( |
338 | $code, |
339 | package_name => $class_name, |
340 | name => $symbol, |
341 | ); |
7855ddba |
342 | } |
0ac992ee |
343 | |
7855ddba |
344 | return $map; |
c4260b45 |
345 | } |
346 | |
c9e77dbb |
347 | # Instance Construction & Cloning |
348 | |
5f3c057a |
349 | sub new_object { |
350 | my $class = shift; |
651955fb |
351 | # NOTE: |
0ac992ee |
352 | # we need to protect the integrity of the |
651955fb |
353 | # Class::MOP::Class singletons here, so we |
354 | # delegate this to &construct_class_instance |
355 | # which will deal with the singletons |
356 | return $class->construct_class_instance(@_) |
357 | if $class->name->isa('Class::MOP::Class'); |
24869f62 |
358 | return $class->construct_instance(@_); |
5f3c057a |
359 | } |
e16da3e6 |
360 | |
361 | sub construct_instance { |
cbd9f942 |
362 | my ($class, %params) = @_; |
0e76a376 |
363 | my $meta_instance = $class->get_meta_instance(); |
364 | my $instance = $meta_instance->create_instance(); |
c9e77dbb |
365 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
f892c0f0 |
366 | $attr->initialize_instance_slot($meta_instance, $instance, \%params); |
cbd9f942 |
367 | } |
0ac992ee |
368 | # NOTE: |
d4ba1677 |
369 | # this will only work for a HASH instance type |
370 | if ($class->is_anon_class) { |
9b522fc4 |
371 | (Scalar::Util::reftype($instance) eq 'HASH') |
d4ba1677 |
372 | || confess "Currently only HASH based instances are supported with instance of anon-classes"; |
373 | # NOTE: |
374 | # At some point we should make this official |
0ac992ee |
375 | # as a reserved slot name, but right now I am |
d4ba1677 |
376 | # going to keep it here. |
377 | # my $RESERVED_MOP_SLOT = '__MOP__'; |
378 | $instance->{'__MOP__'} = $class; |
379 | } |
2d711cc8 |
380 | return $instance; |
381 | } |
382 | |
9b522fc4 |
383 | |
2d711cc8 |
384 | sub get_meta_instance { |
9b522fc4 |
385 | my $self = shift; |
386 | # NOTE: |
387 | # just about any fiddling with @ISA or |
388 | # any fiddling with attributes will |
389 | # also fiddle with the symbol table |
390 | # and therefore invalidate the package |
391 | # cache, in which case we should blow |
392 | # away the meta-instance cache. Of course |
393 | # this will invalidate it more often then |
394 | # is probably needed, but better safe |
395 | # then sorry. |
396 | # - SL |
397 | $self->{'$!_meta_instance'} = undef |
398 | if defined $self->{'$!_package_cache_flag'} && |
399 | $self->{'$!_package_cache_flag'} == Class::MOP::check_package_cache_flag($self->name); |
400 | $self->{'$!_meta_instance'} ||= $self->instance_metaclass->new( |
401 | $self, |
402 | $self->compute_all_applicable_attributes() |
052c2a1a |
403 | ); |
e16da3e6 |
404 | } |
405 | |
5f3c057a |
406 | sub clone_object { |
407 | my $class = shift; |
0ac992ee |
408 | my $instance = shift; |
408ce4ea |
409 | (blessed($instance) && $instance->isa($class->name)) |
f3e20129 |
410 | || confess "You must pass an instance of the metaclass (" . $class->name . "), not ($instance)"; |
411 | |
651955fb |
412 | # NOTE: |
0ac992ee |
413 | # we need to protect the integrity of the |
414 | # Class::MOP::Class singletons here, they |
a740253a |
415 | # should not be cloned. |
0ac992ee |
416 | return $instance if $instance->isa('Class::MOP::Class'); |
f7259199 |
417 | $class->clone_instance($instance, @_); |
5f3c057a |
418 | } |
419 | |
c9e77dbb |
420 | sub clone_instance { |
651955fb |
421 | my ($class, $instance, %params) = @_; |
422 | (blessed($instance)) |
bd1cc5cd |
423 | || confess "You can only clone instances, ($instance) is not a blessed instance"; |
f7259199 |
424 | my $meta_instance = $class->get_meta_instance(); |
0ac992ee |
425 | my $clone = $meta_instance->clone_instance($instance); |
c23184fc |
426 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
de55d708 |
427 | if ( defined( my $init_arg = $attr->init_arg ) ) { |
428 | if (exists $params{$init_arg}) { |
429 | $attr->set_value($clone, $params{$init_arg}); |
430 | } |
c23184fc |
431 | } |
0ac992ee |
432 | } |
433 | return $clone; |
c9e77dbb |
434 | } |
435 | |
3d9e4646 |
436 | sub rebless_instance { |
214e4bd7 |
437 | my ($self, $instance, %params) = @_; |
2a2b8458 |
438 | |
439 | my $old_metaclass; |
440 | if ($instance->can('meta')) { |
441 | ($instance->meta->isa('Class::MOP::Class')) |
442 | || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class'; |
443 | $old_metaclass = $instance->meta; |
444 | } |
445 | else { |
446 | $old_metaclass = $self->initialize(blessed($instance)); |
447 | } |
448 | |
1a720916 |
449 | my $meta_instance = $self->get_meta_instance(); |
408ce4ea |
450 | |
451 | $self->name->isa($old_metaclass->name) |
452 | || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't."; |
9b71b643 |
453 | |
1a720916 |
454 | # rebless! |
3cd40f5e |
455 | $meta_instance->rebless_instance_structure($instance, $self); |
1a720916 |
456 | |
de55d708 |
457 | foreach my $attr ( $self->compute_all_applicable_attributes ) { |
458 | if ( $attr->has_value($instance) ) { |
e253285d |
459 | if ( defined( my $init_arg = $attr->init_arg ) ) { |
214e4bd7 |
460 | $params{$init_arg} = $attr->get_value($instance) |
461 | unless exists $params{$init_arg}; |
462 | } |
463 | else { |
b293f28b |
464 | $attr->set_value($instance, $attr->get_value($instance)); |
e253285d |
465 | } |
de55d708 |
466 | } |
1a720916 |
467 | } |
e253285d |
468 | |
469 | foreach my $attr ($self->compute_all_applicable_attributes) { |
470 | $attr->initialize_instance_slot($meta_instance, $instance, \%params); |
471 | } |
830b326c |
472 | |
473 | $instance; |
3d9e4646 |
474 | } |
475 | |
8b978dd5 |
476 | # Inheritance |
477 | |
478 | sub superclasses { |
8b49a472 |
479 | my $self = shift; |
480 | my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' }; |
8b978dd5 |
481 | if (@_) { |
482 | my @supers = @_; |
8b49a472 |
483 | @{$self->get_package_symbol($var_spec)} = @supers; |
d82060fe |
484 | # NOTE: |
0ac992ee |
485 | # we need to check the metaclass |
84086365 |
486 | # compatibility here so that we can |
0ac992ee |
487 | # be sure that the superclass is |
488 | # not potentially creating an issues |
d82060fe |
489 | # we don't know about |
490 | $self->check_metaclass_compatability(); |
8b978dd5 |
491 | } |
8b49a472 |
492 | @{$self->get_package_symbol($var_spec)}; |
8b978dd5 |
493 | } |
494 | |
7160cad4 |
495 | sub subclasses { |
496 | my $self = shift; |
497 | |
498 | my $super_class = $self->name; |
499 | my @derived_classes; |
500 | |
501 | my $find_derived_classes; |
502 | $find_derived_classes = sub { |
503 | my ($outer_class) = @_; |
504 | |
505 | my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} }; |
506 | |
c1d5345a |
507 | SYMBOL: |
7160cad4 |
508 | for my $symbol ( keys %$symbol_table_hashref ) { |
509 | next SYMBOL if $symbol !~ /\A (\w+):: \z/x; |
510 | my $inner_class = $1; |
511 | |
512 | next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER' |
513 | |
514 | my $class = |
515 | $outer_class |
516 | ? "${outer_class}::$inner_class" |
517 | : $inner_class; |
518 | |
519 | if ( $class->isa($super_class) and $class ne $super_class ) { |
520 | push @derived_classes, $class; |
521 | } |
522 | |
523 | next SYMBOL if $class eq 'main'; # skip 'main::*' |
524 | |
525 | $find_derived_classes->($class); |
526 | } |
527 | }; |
528 | |
529 | my $root_class = q{}; |
530 | $find_derived_classes->($root_class); |
531 | |
532 | undef $find_derived_classes; |
533 | |
534 | @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes; |
535 | |
536 | return @derived_classes; |
537 | } |
538 | |
539 | |
b7bdffc3 |
540 | sub linearized_isa { |
3cf322a0 |
541 | return @{ mro::get_linear_isa( (shift)->name ) }; |
b7bdffc3 |
542 | } |
543 | |
8b978dd5 |
544 | sub class_precedence_list { |
545 | my $self = shift; |
77a143ba |
546 | my $name = $self->name; |
c1d5345a |
547 | |
548 | unless (Class::MOP::IS_RUNNING_ON_5_10()) { |
549 | # NOTE: |
550 | # We need to check for circular inheritance here |
551 | # if we are are not on 5.10, cause 5.8 detects it |
552 | # late. This will do nothing if all is well, and |
553 | # blow up otherwise. Yes, it's an ugly hack, better |
554 | # suggestions are welcome. |
555 | # - SL |
77a143ba |
556 | ($name || return)->isa('This is a test for circular inheritance') |
c1d5345a |
557 | } |
0ac992ee |
558 | |
77a143ba |
559 | # if our mro is c3, we can |
560 | # just grab the linear_isa |
561 | if (mro::get_mro($name) eq 'c3') { |
562 | return @{ mro::get_linear_isa($name) } |
563 | } |
564 | else { |
565 | # NOTE: |
566 | # we can't grab the linear_isa for dfs |
567 | # since it has all the duplicates |
568 | # already removed. |
569 | return ( |
570 | $name, |
571 | map { |
572 | $self->initialize($_)->class_precedence_list() |
573 | } $self->superclasses() |
574 | ); |
575 | } |
8b978dd5 |
576 | } |
577 | |
0882828e |
578 | ## Methods |
579 | |
580 | sub add_method { |
581 | my ($self, $method_name, $method) = @_; |
582 | (defined $method_name && $method_name) |
583 | || confess "You must define a method name"; |
0ac992ee |
584 | |
7855ddba |
585 | my $body; |
7855ddba |
586 | if (blessed($method)) { |
0ac992ee |
587 | $body = $method->body; |
408ce4ea |
588 | if ($method->package_name ne $self->name && |
4c105333 |
589 | $method->name ne $method_name) { |
bb99e529 |
590 | warn "Hello there, got something for you." |
4c105333 |
591 | . " Method says " . $method->package_name . " " . $method->name |
408ce4ea |
592 | . " Class says " . $self->name . " " . $method_name; |
4c105333 |
593 | $method = $method->clone( |
408ce4ea |
594 | package_name => $self->name, |
4c105333 |
595 | name => $method_name |
596 | ) if $method->can('clone'); |
597 | } |
7855ddba |
598 | } |
0ac992ee |
599 | else { |
7855ddba |
600 | $body = $method; |
9b522fc4 |
601 | ('CODE' eq ref($body)) |
0ac992ee |
602 | || confess "Your code block must be a CODE reference"; |
4c105333 |
603 | $method = $self->method_metaclass->wrap( |
604 | $body => ( |
408ce4ea |
605 | package_name => $self->name, |
4c105333 |
606 | name => $method_name |
607 | ) |
608 | ); |
7855ddba |
609 | } |
0f71bc80 |
610 | $self->get_method_map->{$method_name} = $method; |
4c105333 |
611 | |
408ce4ea |
612 | my $full_method_name = ($self->name . '::' . $method_name); |
8b49a472 |
613 | $self->add_package_symbol( |
614 | { sigil => '&', type => 'CODE', name => $method_name }, |
4c105333 |
615 | Class::MOP::subname($full_method_name => $body) |
616 | ); |
715adbb7 |
617 | $self->update_package_cache_flag; |
0882828e |
618 | } |
619 | |
a4258ffd |
620 | { |
2d711cc8 |
621 | my $fetch_and_prepare_method = sub { |
622 | my ($self, $method_name) = @_; |
623 | # fetch it locally |
624 | my $method = $self->get_method($method_name); |
625 | # if we dont have local ... |
626 | unless ($method) { |
195f5bf8 |
627 | # try to find the next method |
628 | $method = $self->find_next_method_by_name($method_name); |
629 | # die if it does not exist |
630 | (defined $method) |
804f7d24 |
631 | || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name; |
0ac992ee |
632 | # and now make sure to wrap it |
195f5bf8 |
633 | # even if it is already wrapped |
634 | # because we need a new sub ref |
2d711cc8 |
635 | $method = Class::MOP::Method::Wrapped->wrap($method); |
195f5bf8 |
636 | } |
637 | else { |
0ac992ee |
638 | # now make sure we wrap it properly |
195f5bf8 |
639 | $method = Class::MOP::Method::Wrapped->wrap($method) |
0ac992ee |
640 | unless $method->isa('Class::MOP::Method::Wrapped'); |
641 | } |
642 | $self->add_method($method_name => $method); |
2d711cc8 |
643 | return $method; |
644 | }; |
645 | |
646 | sub add_before_method_modifier { |
647 | my ($self, $method_name, $method_modifier) = @_; |
648 | (defined $method_name && $method_name) |
0ac992ee |
649 | || confess "You must pass in a method name"; |
2d711cc8 |
650 | my $method = $fetch_and_prepare_method->($self, $method_name); |
4c105333 |
651 | $method->add_before_modifier( |
652 | Class::MOP::subname(':before' => $method_modifier) |
653 | ); |
2d711cc8 |
654 | } |
655 | |
656 | sub add_after_method_modifier { |
657 | my ($self, $method_name, $method_modifier) = @_; |
658 | (defined $method_name && $method_name) |
0ac992ee |
659 | || confess "You must pass in a method name"; |
2d711cc8 |
660 | my $method = $fetch_and_prepare_method->($self, $method_name); |
4c105333 |
661 | $method->add_after_modifier( |
662 | Class::MOP::subname(':after' => $method_modifier) |
663 | ); |
2d711cc8 |
664 | } |
0ac992ee |
665 | |
2d711cc8 |
666 | sub add_around_method_modifier { |
667 | my ($self, $method_name, $method_modifier) = @_; |
668 | (defined $method_name && $method_name) |
669 | || confess "You must pass in a method name"; |
670 | my $method = $fetch_and_prepare_method->($self, $method_name); |
4c105333 |
671 | $method->add_around_modifier( |
672 | Class::MOP::subname(':around' => $method_modifier) |
673 | ); |
0ac992ee |
674 | } |
a4258ffd |
675 | |
0ac992ee |
676 | # NOTE: |
8c936afc |
677 | # the methods above used to be named like this: |
678 | # ${pkg}::${method}:(before|after|around) |
679 | # but this proved problematic when using one modifier |
680 | # to wrap multiple methods (something which is likely |
681 | # to happen pretty regularly IMO). So instead of naming |
0ac992ee |
682 | # it like this, I have chosen to just name them purely |
8c936afc |
683 | # with their modifier names, like so: |
684 | # :(before|after|around) |
0ac992ee |
685 | # The fact is that in a stack trace, it will be fairly |
8c936afc |
686 | # evident from the context what method they are attached |
687 | # to, and so don't need the fully qualified name. |
ee5e71d4 |
688 | } |
689 | |
663f8198 |
690 | sub alias_method { |
691 | my ($self, $method_name, $method) = @_; |
692 | (defined $method_name && $method_name) |
693 | || confess "You must define a method name"; |
de19f115 |
694 | |
0f71bc80 |
695 | my $body = (blessed($method) ? $method->body : $method); |
9b522fc4 |
696 | ('CODE' eq ref($body)) |
0ac992ee |
697 | || confess "Your code block must be a CODE reference"; |
698 | |
8b49a472 |
699 | $self->add_package_symbol( |
700 | { sigil => '&', type => 'CODE', name => $method_name } => $body |
701 | ); |
715adbb7 |
702 | $self->update_package_cache_flag; |
16e960bd |
703 | } |
704 | |
de19f115 |
705 | sub has_method { |
706 | my ($self, $method_name) = @_; |
707 | (defined $method_name && $method_name) |
0ac992ee |
708 | || confess "You must define a method name"; |
709 | |
710 | return 0 unless exists $self->get_method_map->{$method_name}; |
de19f115 |
711 | return 1; |
0882828e |
712 | } |
713 | |
714 | sub get_method { |
c9b8b7f9 |
715 | my ($self, $method_name) = @_; |
0882828e |
716 | (defined $method_name && $method_name) |
717 | || confess "You must define a method name"; |
0ac992ee |
718 | |
0f71bc80 |
719 | # NOTE: |
720 | # I don't really need this here, because |
0ac992ee |
721 | # if the method_map is missing a key it |
0f71bc80 |
722 | # will just return undef for me now |
723 | # return unless $self->has_method($method_name); |
0ac992ee |
724 | |
7855ddba |
725 | return $self->get_method_map->{$method_name}; |
c9b8b7f9 |
726 | } |
727 | |
728 | sub remove_method { |
729 | my ($self, $method_name) = @_; |
730 | (defined $method_name && $method_name) |
731 | || confess "You must define a method name"; |
0ac992ee |
732 | |
e0e4674a |
733 | my $removed_method = delete $self->get_method_map->{$method_name}; |
734 | |
8b49a472 |
735 | $self->remove_package_symbol( |
736 | { sigil => '&', type => 'CODE', name => $method_name } |
737 | ); |
e0e4674a |
738 | |
715adbb7 |
739 | $self->update_package_cache_flag; |
0ac992ee |
740 | |
c9b8b7f9 |
741 | return $removed_method; |
742 | } |
743 | |
744 | sub get_method_list { |
745 | my $self = shift; |
0f71bc80 |
746 | keys %{$self->get_method_map}; |
7855ddba |
747 | } |
748 | |
749 | sub find_method_by_name { |
750 | my ($self, $method_name) = @_; |
b9575695 |
751 | (defined $method_name && $method_name) |
0ac992ee |
752 | || confess "You must define a method name to find"; |
b7bdffc3 |
753 | foreach my $class ($self->linearized_isa) { |
b9575695 |
754 | # fetch the meta-class ... |
755 | my $meta = $self->initialize($class); |
0ac992ee |
756 | return $meta->get_method($method_name) |
b9575695 |
757 | if $meta->has_method($method_name); |
758 | } |
759 | return; |
a5eca695 |
760 | } |
761 | |
762 | sub compute_all_applicable_methods { |
763 | my $self = shift; |
b7bdffc3 |
764 | my (@methods, %seen_method); |
765 | foreach my $class ($self->linearized_isa) { |
a5eca695 |
766 | # fetch the meta-class ... |
767 | my $meta = $self->initialize($class); |
0ac992ee |
768 | foreach my $method_name ($meta->get_method_list()) { |
a5eca695 |
769 | next if exists $seen_method{$method_name}; |
770 | $seen_method{$method_name}++; |
771 | push @methods => { |
0ac992ee |
772 | name => $method_name, |
a5eca695 |
773 | class => $class, |
774 | code => $meta->get_method($method_name) |
775 | }; |
776 | } |
777 | } |
778 | return @methods; |
779 | } |
780 | |
a5eca695 |
781 | sub find_all_methods_by_name { |
782 | my ($self, $method_name) = @_; |
783 | (defined $method_name && $method_name) |
0ac992ee |
784 | || confess "You must define a method name to find"; |
a5eca695 |
785 | my @methods; |
b7bdffc3 |
786 | foreach my $class ($self->linearized_isa) { |
a5eca695 |
787 | # fetch the meta-class ... |
96ceced8 |
788 | my $meta = $self->initialize($class); |
a5eca695 |
789 | push @methods => { |
0ac992ee |
790 | name => $method_name, |
a5eca695 |
791 | class => $class, |
792 | code => $meta->get_method($method_name) |
793 | } if $meta->has_method($method_name); |
794 | } |
795 | return @methods; |
8b978dd5 |
796 | } |
797 | |
96ceced8 |
798 | sub find_next_method_by_name { |
799 | my ($self, $method_name) = @_; |
800 | (defined $method_name && $method_name) |
0ac992ee |
801 | || confess "You must define a method name to find"; |
b7bdffc3 |
802 | my @cpl = $self->linearized_isa; |
2d711cc8 |
803 | shift @cpl; # discard ourselves |
96ceced8 |
804 | foreach my $class (@cpl) { |
96ceced8 |
805 | # fetch the meta-class ... |
806 | my $meta = $self->initialize($class); |
0ac992ee |
807 | return $meta->get_method($method_name) |
2d711cc8 |
808 | if $meta->has_method($method_name); |
96ceced8 |
809 | } |
2d711cc8 |
810 | return; |
96ceced8 |
811 | } |
812 | |
552e3d24 |
813 | ## Attributes |
814 | |
e16da3e6 |
815 | sub add_attribute { |
2e41896e |
816 | my $self = shift; |
817 | # either we have an attribute object already |
818 | # or we need to create one from the args provided |
819 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
820 | # make sure it is derived from the correct type though |
821 | ($attribute->isa('Class::MOP::Attribute')) |
0ac992ee |
822 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
b1897d4d |
823 | |
824 | # first we attach our new attribute |
0ac992ee |
825 | # because it might need certain information |
b1897d4d |
826 | # about the class which it is attached to |
9ec169fe |
827 | $attribute->attach_to_class($self); |
0ac992ee |
828 | |
829 | # then we remove attributes of a conflicting |
830 | # name here so that we can properly detach |
831 | # the old attr object, and remove any |
b1897d4d |
832 | # accessors it would have generated |
408ce4ea |
833 | $self->remove_attribute($attribute->name) |
834 | if $self->has_attribute($attribute->name); |
0ac992ee |
835 | |
b1897d4d |
836 | # then onto installing the new accessors |
2d711cc8 |
837 | $attribute->install_accessors(); |
408ce4ea |
838 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
839 | } |
840 | |
841 | sub has_attribute { |
842 | my ($self, $attribute_name) = @_; |
843 | (defined $attribute_name && $attribute_name) |
844 | || confess "You must define an attribute name"; |
0ac992ee |
845 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
846 | } |
e16da3e6 |
847 | |
848 | sub get_attribute { |
849 | my ($self, $attribute_name) = @_; |
850 | (defined $attribute_name && $attribute_name) |
851 | || confess "You must define an attribute name"; |
0ac992ee |
852 | return $self->get_attribute_map->{$attribute_name} |
b1897d4d |
853 | # NOTE: |
854 | # this will return undef anyway, so no need ... |
0ac992ee |
855 | # if $self->has_attribute($attribute_name); |
856 | #return; |
857 | } |
e16da3e6 |
858 | |
859 | sub remove_attribute { |
860 | my ($self, $attribute_name) = @_; |
861 | (defined $attribute_name && $attribute_name) |
862 | || confess "You must define an attribute name"; |
0ac992ee |
863 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
864 | return unless defined $removed_attribute; |
0ac992ee |
865 | delete $self->get_attribute_map->{$attribute_name}; |
866 | $removed_attribute->remove_accessors(); |
2d711cc8 |
867 | $removed_attribute->detach_from_class(); |
e16da3e6 |
868 | return $removed_attribute; |
0ac992ee |
869 | } |
e16da3e6 |
870 | |
871 | sub get_attribute_list { |
872 | my $self = shift; |
f7259199 |
873 | keys %{$self->get_attribute_map}; |
0ac992ee |
874 | } |
e16da3e6 |
875 | |
876 | sub compute_all_applicable_attributes { |
877 | my $self = shift; |
b7bdffc3 |
878 | my (@attrs, %seen_attr); |
879 | foreach my $class ($self->linearized_isa) { |
e16da3e6 |
880 | # fetch the meta-class ... |
f7259199 |
881 | my $meta = $self->initialize($class); |
0ac992ee |
882 | foreach my $attr_name ($meta->get_attribute_list()) { |
e16da3e6 |
883 | next if exists $seen_attr{$attr_name}; |
884 | $seen_attr{$attr_name}++; |
c9e77dbb |
885 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
886 | } |
887 | } |
0ac992ee |
888 | return @attrs; |
e16da3e6 |
889 | } |
2eb717d5 |
890 | |
058c1cf5 |
891 | sub find_attribute_by_name { |
892 | my ($self, $attr_name) = @_; |
b7bdffc3 |
893 | foreach my $class ($self->linearized_isa) { |
058c1cf5 |
894 | # fetch the meta-class ... |
895 | my $meta = $self->initialize($class); |
896 | return $meta->get_attribute($attr_name) |
897 | if $meta->has_attribute($attr_name); |
898 | } |
899 | return; |
900 | } |
901 | |
857f87a7 |
902 | ## Class closing |
903 | |
904 | sub is_mutable { 1 } |
905 | sub is_immutable { 0 } |
906 | |
b817e248 |
907 | # NOTE: |
908 | # Why I changed this (groditi) |
909 | # - One Metaclass may have many Classes through many Metaclass instances |
910 | # - One Metaclass should only have one Immutable Transformer instance |
911 | # - Each Class may have different Immutabilizing options |
912 | # - Therefore each Metaclass instance may have different Immutabilizing options |
913 | # - We need to store one Immutable Transformer instance per Metaclass |
914 | # - We need to store one set of Immutable Transformer options per Class |
915 | # - Upon make_mutable we may delete the Immutabilizing options |
916 | # - We could clean the immutable Transformer instance when there is no more |
917 | # immutable Classes of that type, but we can also keep it in case |
918 | # another class with this same Metaclass becomes immutable. It is a case |
919 | # of trading of storing an instance to avoid unnecessary instantiations of |
920 | # Immutable Transformers. You may view this as a memory leak, however |
921 | # Because we have few Metaclasses, in practice it seems acceptable |
922 | # - To allow Immutable Transformers instances to be cleaned up we could weaken |
923 | # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM |
04dd7510 |
924 | |
c23184fc |
925 | { |
119f3a92 |
926 | |
d9586da2 |
927 | my %IMMUTABLE_TRANSFORMERS; |
0ac992ee |
928 | my %IMMUTABLE_OPTIONS; |
119f3a92 |
929 | |
930 | sub get_immutable_options { |
931 | my $self = shift; |
932 | return if $self->is_mutable; |
933 | confess "unable to find immutabilizing options" |
934 | unless exists $IMMUTABLE_OPTIONS{$self->name}; |
935 | my %options = %{$IMMUTABLE_OPTIONS{$self->name}}; |
936 | delete $options{IMMUTABLE_TRANSFORMER}; |
937 | return \%options; |
938 | } |
939 | |
940 | sub get_immutable_transformer { |
941 | my $self = shift; |
942 | if( $self->is_mutable ){ |
943 | my $class = blessed $self || $self; |
944 | return $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer; |
945 | } |
946 | confess "unable to find transformer for immutable class" |
947 | unless exists $IMMUTABLE_OPTIONS{$self->name}; |
948 | return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER}; |
949 | } |
950 | |
c23184fc |
951 | sub make_immutable { |
0ac992ee |
952 | my $self = shift; |
04dd7510 |
953 | my %options = @_; |
d9586da2 |
954 | |
119f3a92 |
955 | my $transformer = $self->get_immutable_transformer; |
229910b5 |
956 | $transformer->make_metaclass_immutable($self, \%options); |
7f63694d |
957 | $IMMUTABLE_OPTIONS{$self->name} = |
d9586da2 |
958 | { %options, IMMUTABLE_TRANSFORMER => $transformer }; |
04dd7510 |
959 | |
960 | if( exists $options{debug} && $options{debug} ){ |
d9586da2 |
961 | print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS; |
962 | print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS; |
04dd7510 |
963 | } |
119f3a92 |
964 | |
09c6e1d2 |
965 | 1; |
c23184fc |
966 | } |
0ac992ee |
967 | |
968 | sub make_mutable{ |
969 | my $self = shift; |
970 | return if $self->is_mutable; |
7f63694d |
971 | my $options = delete $IMMUTABLE_OPTIONS{$self->name}; |
1d68af04 |
972 | confess "unable to find immutabilizing options" unless ref $options; |
d9586da2 |
973 | my $transformer = delete $options->{IMMUTABLE_TRANSFORMER}; |
229910b5 |
974 | $transformer->make_metaclass_mutable($self, $options); |
09c6e1d2 |
975 | 1; |
0ac992ee |
976 | } |
d9586da2 |
977 | } |
0ac992ee |
978 | |
d9586da2 |
979 | sub create_immutable_transformer { |
980 | my $self = shift; |
981 | my $class = Class::MOP::Immutable->new($self, { |
5f3efd66 |
982 | read_only => [qw/superclasses/], |
983 | cannot_call => [qw/ |
d9586da2 |
984 | add_method |
985 | alias_method |
986 | remove_method |
987 | add_attribute |
988 | remove_attribute |
d9586da2 |
989 | remove_package_symbol |
5f3efd66 |
990 | /], |
991 | memoize => { |
d9586da2 |
992 | class_precedence_list => 'ARRAY', |
b7bdffc3 |
993 | linearized_isa => 'ARRAY', |
d9586da2 |
994 | compute_all_applicable_attributes => 'ARRAY', |
995 | get_meta_instance => 'SCALAR', |
996 | get_method_map => 'SCALAR', |
5f3efd66 |
997 | }, |
998 | # NOTE: |
999 | # this is ugly, but so are typeglobs, |
1000 | # so whattayahgonnadoboutit |
1001 | # - SL |
1002 | wrapped => { |
1003 | add_package_symbol => sub { |
1004 | my $original = shift; |
1005 | confess "Cannot add package symbols to an immutable metaclass" |
1006 | unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol'; |
1007 | goto $original->body; |
1008 | }, |
1009 | }, |
d9586da2 |
1010 | }); |
1011 | return $class; |
857f87a7 |
1012 | } |
1013 | |
8b978dd5 |
1014 | 1; |
1015 | |
1016 | __END__ |
1017 | |
1018 | =pod |
1019 | |
0ac992ee |
1020 | =head1 NAME |
8b978dd5 |
1021 | |
1022 | Class::MOP::Class - Class Meta Object |
1023 | |
1024 | =head1 SYNOPSIS |
1025 | |
0ac992ee |
1026 | # assuming that class Foo |
8c936afc |
1027 | # has been defined, you can |
0ac992ee |
1028 | |
fe122940 |
1029 | # use this for introspection ... |
0ac992ee |
1030 | |
fe122940 |
1031 | # add a method to Foo ... |
1032 | Foo->meta->add_method('bar' => sub { ... }) |
0ac992ee |
1033 | |
1034 | # get a list of all the classes searched |
1035 | # the method dispatcher in the correct order |
fe122940 |
1036 | Foo->meta->class_precedence_list() |
0ac992ee |
1037 | |
fe122940 |
1038 | # remove a method from Foo |
1039 | Foo->meta->remove_method('bar'); |
0ac992ee |
1040 | |
fe122940 |
1041 | # or use this to actually create classes ... |
0ac992ee |
1042 | |
88dd563c |
1043 | Class::MOP::Class->create('Bar' => ( |
1044 | version => '0.01', |
fe122940 |
1045 | superclasses => [ 'Foo' ], |
1046 | attributes => [ |
1047 | Class::MOP:::Attribute->new('$bar'), |
0ac992ee |
1048 | Class::MOP:::Attribute->new('$baz'), |
fe122940 |
1049 | ], |
1050 | methods => { |
1051 | calculate_bar => sub { ... }, |
0ac992ee |
1052 | construct_baz => sub { ... } |
fe122940 |
1053 | } |
1054 | )); |
1055 | |
8b978dd5 |
1056 | =head1 DESCRIPTION |
1057 | |
0ac992ee |
1058 | This is the largest and currently most complex part of the Perl 5 |
1059 | meta-object protocol. It controls the introspection and |
1060 | manipulation of Perl 5 classes (and it can create them too). The |
1061 | best way to understand what this module can do, is to read the |
fe122940 |
1062 | documentation for each of it's methods. |
1063 | |
552e3d24 |
1064 | =head1 METHODS |
1065 | |
2eb717d5 |
1066 | =head2 Self Introspection |
1067 | |
1068 | =over 4 |
1069 | |
1070 | =item B<meta> |
1071 | |
0ac992ee |
1072 | This will return a B<Class::MOP::Class> instance which is related |
1073 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
fe122940 |
1074 | introspect itself. |
1075 | |
0ac992ee |
1076 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
1077 | bootstrap this module by installing a number of attribute meta-objects |
1078 | into it's metaclass. This will allow this class to reap all the benifits |
1079 | of the MOP when subclassing it. |
2eb717d5 |
1080 | |
1081 | =back |
1082 | |
552e3d24 |
1083 | =head2 Class construction |
1084 | |
0ac992ee |
1085 | These methods will handle creating B<Class::MOP::Class> objects, |
1086 | which can be used to both create new classes, and analyze |
1087 | pre-existing classes. |
552e3d24 |
1088 | |
0ac992ee |
1089 | This module will internally store references to all the instances |
1090 | you create with these methods, so that they do not need to be |
552e3d24 |
1091 | created any more than nessecary. Basically, they are singletons. |
1092 | |
1093 | =over 4 |
1094 | |
0ac992ee |
1095 | =item B<create ($package_name, |
1096 | version =E<gt> ?$version, |
1097 | authority =E<gt> ?$authority, |
1098 | superclasses =E<gt> ?@superclasses, |
1099 | methods =E<gt> ?%methods, |
a2e85e6c |
1100 | attributes =E<gt> ?%attributes)> |
552e3d24 |
1101 | |
0ac992ee |
1102 | This returns a B<Class::MOP::Class> object, bringing the specified |
1103 | C<$package_name> into existence and adding any of the C<$version>, |
1104 | C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to |
88dd563c |
1105 | it. |
552e3d24 |
1106 | |
0ac992ee |
1107 | =item B<create_anon_class (superclasses =E<gt> ?@superclasses, |
1108 | methods =E<gt> ?%methods, |
587aca23 |
1109 | attributes =E<gt> ?%attributes)> |
1110 | |
0ac992ee |
1111 | This will create an anonymous class, it works much like C<create> but |
1112 | it does not need a C<$package_name>. Instead it will create a suitably |
587aca23 |
1113 | unique package name for you to stash things into. |
1114 | |
0ac992ee |
1115 | On very important distinction is that anon classes are destroyed once |
1116 | the metaclass they are attached to goes out of scope. In the DESTROY |
1117 | method, the created package will be removed from the symbol table. |
823a5d31 |
1118 | |
d4ba1677 |
1119 | It is also worth noting that any instances created with an anon-class |
0ac992ee |
1120 | will keep a special reference to the anon-meta which will prevent the |
1121 | anon-class from going out of scope until all instances of it have also |
1122 | been destroyed. This however only works for HASH based instance types, |
1123 | as we use a special reserved slot (C<__MOP__>) to store this. |
d4ba1677 |
1124 | |
66b3dded |
1125 | =item B<initialize ($package_name, %options)> |
552e3d24 |
1126 | |
0ac992ee |
1127 | This initializes and returns returns a B<Class::MOP::Class> object |
a2e85e6c |
1128 | for a given a C<$package_name>. |
1129 | |
66b3dded |
1130 | =item B<reinitialize ($package_name, %options)> |
1131 | |
1132 | This removes the old metaclass, and creates a new one in it's place. |
0ac992ee |
1133 | Do B<not> use this unless you really know what you are doing, it could |
1134 | very easily make a very large mess of your program. |
66b3dded |
1135 | |
651955fb |
1136 | =item B<construct_class_instance (%options)> |
a2e85e6c |
1137 | |
0ac992ee |
1138 | This will construct an instance of B<Class::MOP::Class>, it is |
1139 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
1140 | to use C<construct_instance> once all the bootstrapping is done. This |
a2e85e6c |
1141 | method is used internally by C<initialize> and should never be called |
1142 | from outside of that method really. |
552e3d24 |
1143 | |
550d56db |
1144 | =item B<check_metaclass_compatability> |
1145 | |
0ac992ee |
1146 | This method is called as the very last thing in the |
1147 | C<construct_class_instance> method. This will check that the |
1148 | metaclass you are creating is compatible with the metaclasses of all |
1149 | your ancestors. For more inforamtion about metaclass compatibility |
550d56db |
1150 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
1151 | |
715adbb7 |
1152 | =item B<update_package_cache_flag> |
e0e4674a |
1153 | |
1154 | This will reset the package cache flag for this particular metaclass |
1155 | it is basically the value of the C<Class::MOP::get_package_cache_flag> |
1156 | function. This is very rarely needed from outside of C<Class::MOP::Class> |
1157 | but in some cases you might want to use it, so it is here. |
1158 | |
715adbb7 |
1159 | =item B<reset_package_cache_flag> |
1160 | |
127d39a7 |
1161 | Clears the package cache flag to announce to the internals that we need |
1162 | to rebuild the method map. |
715adbb7 |
1163 | |
552e3d24 |
1164 | =back |
1165 | |
c9e77dbb |
1166 | =head2 Object instance construction and cloning |
a2e85e6c |
1167 | |
0ac992ee |
1168 | These methods are B<entirely optional>, it is up to you whether you want |
c9e77dbb |
1169 | to use them or not. |
552e3d24 |
1170 | |
1171 | =over 4 |
1172 | |
2bab2be6 |
1173 | =item B<instance_metaclass> |
1174 | |
127d39a7 |
1175 | Returns the class name of the instance metaclass, see L<Class::MOP::Instance> |
1176 | for more information on the instance metaclasses. |
1177 | |
2d711cc8 |
1178 | =item B<get_meta_instance> |
1179 | |
127d39a7 |
1180 | Returns an instance of L<Class::MOP::Instance> to be used in the construction |
1181 | of a new instance of the class. |
1182 | |
5f3c057a |
1183 | =item B<new_object (%params)> |
1184 | |
0ac992ee |
1185 | This is a convience method for creating a new object of the class, and |
1186 | blessing it into the appropriate package as well. Ideally your class |
5f3c057a |
1187 | would call a C<new> this method like so: |
1188 | |
0ac992ee |
1189 | sub MyClass::new { |
5f3c057a |
1190 | my ($class, %param) = @_; |
1191 | $class->meta->new_object(%params); |
1192 | } |
1193 | |
cbd9f942 |
1194 | =item B<construct_instance (%params)> |
552e3d24 |
1195 | |
127d39a7 |
1196 | This method is used to construct an instance structure suitable for |
0ac992ee |
1197 | C<bless>-ing into your package of choice. It works in conjunction |
c9e77dbb |
1198 | with the Attribute protocol to collect all applicable attributes. |
1199 | |
0ac992ee |
1200 | This will construct and instance using a HASH ref as storage |
1201 | (currently only HASH references are supported). This will collect all |
1202 | the applicable attributes and layout out the fields in the HASH ref, |
1203 | it will then initialize them using either use the corresponding key |
1204 | in C<%params> or any default value or initializer found in the |
a2e85e6c |
1205 | attribute meta-object. |
727919c5 |
1206 | |
5f3c057a |
1207 | =item B<clone_object ($instance, %params)> |
1208 | |
0ac992ee |
1209 | This is a convience method for cloning an object instance, then |
1210 | blessing it into the appropriate package. This method will call |
1211 | C<clone_instance>, which performs a shallow copy of the object, |
1212 | see that methods documentation for more details. Ideally your |
19d4b5b8 |
1213 | class would call a C<clone> this method like so: |
5f3c057a |
1214 | |
1215 | sub MyClass::clone { |
1216 | my ($self, %param) = @_; |
1217 | $self->meta->clone_object($self, %params); |
1218 | } |
1219 | |
c9e77dbb |
1220 | =item B<clone_instance($instance, %params)> |
1221 | |
0ac992ee |
1222 | This method is a compliment of C<construct_instance> (which means if |
1223 | you override C<construct_instance>, you need to override this one too), |
19d4b5b8 |
1224 | and clones the instance shallowly. |
a27ae83f |
1225 | |
0ac992ee |
1226 | The cloned structure returned is (like with C<construct_instance>) an |
1227 | unC<bless>ed HASH reference, it is your responsibility to then bless |
a27ae83f |
1228 | this cloned structure into the right class (which C<clone_object> will |
1229 | do for you). |
c9e77dbb |
1230 | |
0ac992ee |
1231 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
1232 | as opposed to the deep cloning implemented in prior versions. After much |
1233 | thought, research and discussion, I have decided that anything but basic |
1234 | shallow cloning is outside the scope of the meta-object protocol. I |
1235 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
19d4b5b8 |
1236 | is too I<context-specific> to be part of the MOP. |
1237 | |
214e4bd7 |
1238 | =item B<rebless_instance($instance, ?%params)> |
69663c57 |
1239 | |
1240 | This will change the class of C<$instance> to the class of the invoking |
1241 | C<Class::MOP::Class>. You may only rebless the instance to a subclass of |
214e4bd7 |
1242 | itself. You may pass in optional C<%params> which are like constructor |
1243 | params and will override anything already defined in the instance. |
69663c57 |
1244 | |
552e3d24 |
1245 | =back |
1246 | |
0ac992ee |
1247 | =head2 Informational |
552e3d24 |
1248 | |
b9d9fc0b |
1249 | These are a few predicate methods for asking information about the class. |
552e3d24 |
1250 | |
b9d9fc0b |
1251 | =over 4 |
552e3d24 |
1252 | |
b9d9fc0b |
1253 | =item B<is_anon_class> |
552e3d24 |
1254 | |
96e38ba6 |
1255 | This returns true if the class is a C<Class::MOP::Class> created anon class. |
1256 | |
b9d9fc0b |
1257 | =item B<is_mutable> |
552e3d24 |
1258 | |
96e38ba6 |
1259 | This returns true if the class is still mutable. |
1260 | |
b9d9fc0b |
1261 | =item B<is_immutable> |
552e3d24 |
1262 | |
96e38ba6 |
1263 | This returns true if the class has been made immutable. |
1264 | |
552e3d24 |
1265 | =back |
1266 | |
1267 | =head2 Inheritance Relationships |
1268 | |
1269 | =over 4 |
1270 | |
1271 | =item B<superclasses (?@superclasses)> |
1272 | |
0ac992ee |
1273 | This is a read-write attribute which represents the superclass |
a2e85e6c |
1274 | relationships of the class the B<Class::MOP::Class> instance is |
1275 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
1276 | |
1277 | =item B<class_precedence_list> |
1278 | |
0ac992ee |
1279 | This computes the a list of all the class's ancestors in the same order |
127d39a7 |
1280 | in which method dispatch will be done. This is similair to what |
1281 | B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
1282 | |
b7bdffc3 |
1283 | =item B<linearized_isa> |
1284 | |
1285 | This returns a list based on C<class_precedence_list> but with all |
1286 | duplicates removed. |
1287 | |
6c9f390e |
1288 | =item B<subclasses> |
1289 | |
127d39a7 |
1290 | This returns a list of subclasses for this class. |
6c9f390e |
1291 | |
552e3d24 |
1292 | =back |
1293 | |
1294 | =head2 Methods |
1295 | |
1296 | =over 4 |
1297 | |
c4260b45 |
1298 | =item B<get_method_map> |
1299 | |
127d39a7 |
1300 | Returns a HASH ref of name to CODE reference mapping for this class. |
1301 | |
2e41896e |
1302 | =item B<method_metaclass> |
1303 | |
127d39a7 |
1304 | Returns the class name of the method metaclass, see L<Class::MOP::Method> |
1305 | for more information on the method metaclasses. |
1306 | |
552e3d24 |
1307 | =item B<add_method ($method_name, $method)> |
1308 | |
0ac992ee |
1309 | This will take a C<$method_name> and CODE reference to that |
1310 | C<$method> and install it into the class's package. |
552e3d24 |
1311 | |
0ac992ee |
1312 | B<NOTE>: |
1313 | This does absolutely nothing special to C<$method> |
1314 | other than use B<Sub::Name> to make sure it is tagged with the |
1315 | correct name, and therefore show up correctly in stack traces and |
552e3d24 |
1316 | such. |
1317 | |
663f8198 |
1318 | =item B<alias_method ($method_name, $method)> |
1319 | |
0ac992ee |
1320 | This will take a C<$method_name> and CODE reference to that |
1321 | C<$method> and alias the method into the class's package. |
663f8198 |
1322 | |
0ac992ee |
1323 | B<NOTE>: |
1324 | Unlike C<add_method>, this will B<not> try to name the |
1325 | C<$method> using B<Sub::Name>, it only aliases the method in |
1326 | the class's package. |
663f8198 |
1327 | |
552e3d24 |
1328 | =item B<has_method ($method_name)> |
1329 | |
0ac992ee |
1330 | This just provides a simple way to check if the class implements |
1331 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
1332 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
1333 | |
0ac992ee |
1334 | This will correctly handle functions defined outside of the package |
552e3d24 |
1335 | that use a fully qualified name (C<sub Package::name { ... }>). |
1336 | |
0ac992ee |
1337 | This will correctly handle functions renamed with B<Sub::Name> and |
1338 | installed using the symbol tables. However, if you are naming the |
1339 | subroutine outside of the package scope, you must use the fully |
1340 | qualified name, including the package name, for C<has_method> to |
1341 | correctly identify it. |
552e3d24 |
1342 | |
0ac992ee |
1343 | This will attempt to correctly ignore functions imported from other |
1344 | packages using B<Exporter>. It breaks down if the function imported |
1345 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
1346 | may be a valid method being applied to the class. |
552e3d24 |
1347 | |
0ac992ee |
1348 | In short, this method cannot always be trusted to determine if the |
1349 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
1350 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
1351 | |
1352 | =item B<get_method ($method_name)> |
1353 | |
0ac992ee |
1354 | This will return a Class::MOP::Method instance related to the specified |
86482605 |
1355 | C<$method_name>, or return undef if that method does not exist. |
1356 | |
0ac992ee |
1357 | The Class::MOP::Method is codifiable, so you can use it like a normal |
86482605 |
1358 | CODE reference, see L<Class::MOP::Method> for more information. |
552e3d24 |
1359 | |
f9debadc |
1360 | =item B<find_method_by_name ($method_name)> |
16e960bd |
1361 | |
1362 | This will return a CODE reference of the specified C<$method_name>, |
1363 | or return undef if that method does not exist. |
1364 | |
1365 | Unlike C<get_method> this will also look in the superclasses. |
1366 | |
552e3d24 |
1367 | =item B<remove_method ($method_name)> |
1368 | |
0ac992ee |
1369 | This will attempt to remove a given C<$method_name> from the class. |
1370 | It will return the CODE reference that it has removed, and will |
552e3d24 |
1371 | attempt to use B<Sub::Name> to clear the methods associated name. |
1372 | |
1373 | =item B<get_method_list> |
1374 | |
0ac992ee |
1375 | This will return a list of method names for all I<locally> defined |
1376 | methods. It does B<not> provide a list of all applicable methods, |
1377 | including any inherited ones. If you want a list of all applicable |
552e3d24 |
1378 | methods, use the C<compute_all_applicable_methods> method. |
1379 | |
1380 | =item B<compute_all_applicable_methods> |
1381 | |
0ac992ee |
1382 | This will return a list of all the methods names this class will |
1383 | respond to, taking into account inheritance. The list will be a list of |
1384 | HASH references, each one containing the following information; method |
1385 | name, the name of the class in which the method lives and a CODE |
552e3d24 |
1386 | reference for the actual method. |
1387 | |
1388 | =item B<find_all_methods_by_name ($method_name)> |
1389 | |
0ac992ee |
1390 | This will traverse the inheritence hierarchy and locate all methods |
1391 | with a given C<$method_name>. Similar to |
1392 | C<compute_all_applicable_methods> it returns a list of HASH references |
1393 | with the following information; method name (which will always be the |
1394 | same as C<$method_name>), the name of the class in which the method |
552e3d24 |
1395 | lives and a CODE reference for the actual method. |
1396 | |
0ac992ee |
1397 | The list of methods produced is a distinct list, meaning there are no |
1398 | duplicates in it. This is especially useful for things like object |
1399 | initialization and destruction where you only want the method called |
552e3d24 |
1400 | once, and in the correct order. |
1401 | |
96ceced8 |
1402 | =item B<find_next_method_by_name ($method_name)> |
1403 | |
0ac992ee |
1404 | This will return the first method to match a given C<$method_name> in |
1405 | the superclasses, this is basically equivalent to calling |
96ceced8 |
1406 | C<SUPER::$method_name>, but it can be dispatched at runtime. |
1407 | |
552e3d24 |
1408 | =back |
1409 | |
a4258ffd |
1410 | =head2 Method Modifiers |
1411 | |
0ac992ee |
1412 | Method modifiers are a concept borrowed from CLOS, in which a method |
1413 | can be wrapped with I<before>, I<after> and I<around> method modifiers |
1414 | that will be called everytime the method is called. |
96ceced8 |
1415 | |
1416 | =head3 How method modifiers work? |
1417 | |
0ac992ee |
1418 | Method modifiers work by wrapping the original method and then replacing |
1419 | it in the classes symbol table. The wrappers will handle calling all the |
1420 | modifiers in the appropariate orders and preserving the calling context |
1421 | for the original method. |
1422 | |
1423 | Each method modifier serves a particular purpose, which may not be |
1424 | obvious to users of other method wrapping modules. To start with, the |
1425 | return values of I<before> and I<after> modifiers are ignored. This is |
1426 | because thier purpose is B<not> to filter the input and output of the |
1427 | primary method (this is done with an I<around> modifier). This may seem |
1428 | like an odd restriction to some, but doing this allows for simple code |
1429 | to be added at the begining or end of a method call without jeapordizing |
1430 | the normal functioning of the primary method or placing any extra |
1431 | responsibility on the code of the modifier. Of course if you have more |
1432 | complex needs, then use the I<around> modifier, which uses a variation |
1433 | of continutation passing style to allow for a high degree of flexibility. |
1434 | |
1435 | Before and around modifiers are called in last-defined-first-called order, |
1436 | while after modifiers are called in first-defined-first-called order. So |
96ceced8 |
1437 | the call tree might looks something like this: |
0ac992ee |
1438 | |
96ceced8 |
1439 | before 2 |
1440 | before 1 |
1441 | around 2 |
1442 | around 1 |
1443 | primary |
1444 | after 1 |
1445 | after 2 |
1446 | |
0ac992ee |
1447 | To see examples of using method modifiers, see the following examples |
1448 | included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>, |
1449 | F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a |
96ceced8 |
1450 | classic CLOS usage example in the test F<017_add_method_modifier.t>. |
1451 | |
1452 | =head3 What is the performance impact? |
1453 | |
0ac992ee |
1454 | Of course there is a performance cost associated with method modifiers, |
1455 | but we have made every effort to make that cost be directly proportional |
96ceced8 |
1456 | to the amount of modifier features you utilize. |
1457 | |
0ac992ee |
1458 | The wrapping method does it's best to B<only> do as much work as it |
1459 | absolutely needs to. In order to do this we have moved some of the |
96ceced8 |
1460 | performance costs to set-up time, where they are easier to amortize. |
1461 | |
1462 | All this said, my benchmarks have indicated the following: |
1463 | |
1464 | simple wrapper with no modifiers 100% slower |
1465 | simple wrapper with simple before modifier 400% slower |
1466 | simple wrapper with simple after modifier 450% slower |
1467 | simple wrapper with simple around modifier 500-550% slower |
1468 | simple wrapper with all 3 modifiers 1100% slower |
1469 | |
0ac992ee |
1470 | These numbers may seem daunting, but you must remember, every feature |
1471 | comes with some cost. To put things in perspective, just doing a simple |
96ceced8 |
1472 | C<AUTOLOAD> which does nothing but extract the name of the method called |
0ac992ee |
1473 | and return it costs about 400% over a normal method call. |
96ceced8 |
1474 | |
a4258ffd |
1475 | =over 4 |
1476 | |
1477 | =item B<add_before_method_modifier ($method_name, $code)> |
1478 | |
0ac992ee |
1479 | This will wrap the method at C<$method_name> and the supplied C<$code> |
1480 | will be passed the C<@_> arguments, and called before the original |
1481 | method is called. As specified above, the return value of the I<before> |
1482 | method modifiers is ignored, and it's ability to modify C<@_> is |
1483 | fairly limited. If you need to do either of these things, use an |
96ceced8 |
1484 | C<around> method modifier. |
1485 | |
a4258ffd |
1486 | =item B<add_after_method_modifier ($method_name, $code)> |
1487 | |
0ac992ee |
1488 | This will wrap the method at C<$method_name> so that the original |
1489 | method will be called, it's return values stashed, and then the |
96ceced8 |
1490 | supplied C<$code> will be passed the C<@_> arguments, and called. |
0ac992ee |
1491 | As specified above, the return value of the I<after> method |
1492 | modifiers is ignored, and it cannot modify the return values of |
1493 | the original method. If you need to do either of these things, use an |
96ceced8 |
1494 | C<around> method modifier. |
1495 | |
a4258ffd |
1496 | =item B<add_around_method_modifier ($method_name, $code)> |
1497 | |
0ac992ee |
1498 | This will wrap the method at C<$method_name> so that C<$code> |
1499 | will be called and passed the original method as an extra argument |
1500 | at the begining of the C<@_> argument list. This is a variation of |
1501 | continuation passing style, where the function prepended to C<@_> |
1502 | can be considered a continuation. It is up to C<$code> if it calls |
1503 | the original method or not, there is no restriction on what the |
96ceced8 |
1504 | C<$code> can or cannot do. |
1505 | |
a4258ffd |
1506 | =back |
1507 | |
552e3d24 |
1508 | =head2 Attributes |
1509 | |
0ac992ee |
1510 | It should be noted that since there is no one consistent way to define |
1511 | the attributes of a class in Perl 5. These methods can only work with |
1512 | the information given, and can not easily discover information on |
a2e85e6c |
1513 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
1514 | |
1515 | =over 4 |
1516 | |
2e41896e |
1517 | =item B<attribute_metaclass> |
1518 | |
127d39a7 |
1519 | Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute> |
1520 | for more information on the attribute metaclasses. |
1521 | |
7b31baf4 |
1522 | =item B<get_attribute_map> |
1523 | |
127d39a7 |
1524 | This returns a HASH ref of name to attribute meta-object mapping. |
1525 | |
1526 | =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))> |
552e3d24 |
1527 | |
8203616d |
1528 | This stores the C<$attribute_meta_object> (or creates one from the |
0ac992ee |
1529 | C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class> |
1530 | instance associated with the given class. Unlike methods, attributes |
1531 | within the MOP are stored as meta-information only. They will be used |
8203616d |
1532 | later to construct instances from (see C<construct_instance> above). |
0ac992ee |
1533 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
1534 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
1535 | section. |
1536 | |
0ac992ee |
1537 | It should be noted that any accessor, reader/writer or predicate |
1538 | methods which the C<$attribute_meta_object> has will be installed |
a2e85e6c |
1539 | into the class at this time. |
552e3d24 |
1540 | |
86482605 |
1541 | B<NOTE> |
0ac992ee |
1542 | If an attribute already exists for C<$attribute_name>, the old one |
1543 | will be removed (as well as removing all it's accessors), and then |
86482605 |
1544 | the new one added. |
1545 | |
552e3d24 |
1546 | =item B<has_attribute ($attribute_name)> |
1547 | |
0ac992ee |
1548 | Checks to see if this class has an attribute by the name of |
552e3d24 |
1549 | C<$attribute_name> and returns a boolean. |
1550 | |
1551 | =item B<get_attribute ($attribute_name)> |
1552 | |
0ac992ee |
1553 | Returns the attribute meta-object associated with C<$attribute_name>, |
1554 | if none is found, it will return undef. |
552e3d24 |
1555 | |
1556 | =item B<remove_attribute ($attribute_name)> |
1557 | |
0ac992ee |
1558 | This will remove the attribute meta-object stored at |
1559 | C<$attribute_name>, then return the removed attribute meta-object. |
552e3d24 |
1560 | |
0ac992ee |
1561 | B<NOTE:> |
1562 | Removing an attribute will only affect future instances of |
1563 | the class, it will not make any attempt to remove the attribute from |
552e3d24 |
1564 | any existing instances of the class. |
1565 | |
0ac992ee |
1566 | It should be noted that any accessor, reader/writer or predicate |
1567 | methods which the attribute meta-object stored at C<$attribute_name> |
1568 | has will be removed from the class at this time. This B<will> make |
1569 | these attributes somewhat inaccessable in previously created |
1570 | instances. But if you are crazy enough to do this at runtime, then |
a2e85e6c |
1571 | you are crazy enough to deal with something like this :). |
1572 | |
552e3d24 |
1573 | =item B<get_attribute_list> |
1574 | |
0ac992ee |
1575 | This returns a list of attribute names which are defined in the local |
1576 | class. If you want a list of all applicable attributes for a class, |
552e3d24 |
1577 | use the C<compute_all_applicable_attributes> method. |
1578 | |
1579 | =item B<compute_all_applicable_attributes> |
1580 | |
0ac992ee |
1581 | This will traverse the inheritance heirachy and return a list of all |
1582 | the applicable attributes for this class. It does not construct a |
1583 | HASH reference like C<compute_all_applicable_methods> because all |
1584 | that same information is discoverable through the attribute |
c9e77dbb |
1585 | meta-object itself. |
552e3d24 |
1586 | |
058c1cf5 |
1587 | =item B<find_attribute_by_name ($attr_name)> |
1588 | |
0ac992ee |
1589 | This method will traverse the inheritance heirachy and find the |
1590 | first attribute whose name matches C<$attr_name>, then return it. |
058c1cf5 |
1591 | It will return undef if nothing is found. |
1592 | |
552e3d24 |
1593 | =back |
1594 | |
96e38ba6 |
1595 | =head2 Class Immutability |
857f87a7 |
1596 | |
1597 | =over 4 |
1598 | |
96e38ba6 |
1599 | =item B<make_immutable (%options)> |
1600 | |
0ac992ee |
1601 | This method will invoke a tranforamtion upon the class which will |
1602 | make it immutable. Details of this transformation can be found in |
96e38ba6 |
1603 | the L<Class::MOP::Immutable> documentation. |
857f87a7 |
1604 | |
0ac992ee |
1605 | =item B<make_mutable> |
1606 | |
1607 | This method will reverse tranforamtion upon the class which |
1608 | made it immutable. |
1609 | |
119f3a92 |
1610 | =item B<get_immutable_transformer> |
1611 | |
1612 | Return a transformer suitable for making this class immutable or, if this |
1613 | class is immutable, the transformer used to make it immutable. |
1614 | |
1615 | =item B<get_immutable_options> |
1616 | |
1617 | If the class is immutable, return the options used to make it immutable. |
1618 | |
b817e248 |
1619 | =item B<create_immutable_transformer> |
1620 | |
1621 | Create a transformer suitable for making this class immutable |
1622 | |
857f87a7 |
1623 | =back |
1624 | |
1a09d9cc |
1625 | =head1 AUTHORS |
8b978dd5 |
1626 | |
a2e85e6c |
1627 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
1628 | |
1629 | =head1 COPYRIGHT AND LICENSE |
1630 | |
69e3ab0a |
1631 | Copyright 2006-2008 by Infinity Interactive, Inc. |
8b978dd5 |
1632 | |
1633 | L<http://www.iinteractive.com> |
1634 | |
1635 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
1636 | it under the same terms as Perl itself. |
8b978dd5 |
1637 | |
798baea5 |
1638 | =cut |