Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Class; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Carp 'confess'; |
77e5fce4 |
8 | use Scalar::Util 'blessed', 'reftype', 'weaken'; |
8b978dd5 |
9 | use Sub::Name 'subname'; |
96ceced8 |
10 | use B 'svref_2object'; |
8b978dd5 |
11 | |
f0480c45 |
12 | our $VERSION = '0.17'; |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
8b978dd5 |
14 | |
2243a22b |
15 | use base 'Class::MOP::Module'; |
16 | |
839ea973 |
17 | use Class::MOP::Instance; |
18 | |
aa448b16 |
19 | # Self-introspection |
2eb717d5 |
20 | |
aa448b16 |
21 | sub meta { Class::MOP::Class->initialize(blessed($_[0]) || $_[0]) } |
2eb717d5 |
22 | |
6d5355c3 |
23 | # Class globals ... |
24 | |
25 | # NOTE: |
26 | # we need a sufficiently annoying prefix |
27 | # this should suffice for now, this is |
28 | # used in a couple of places below, so |
29 | # need to put it up here for now. |
30 | my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; |
31 | |
8b978dd5 |
32 | # Creation |
33 | |
f7259199 |
34 | { |
bfe4d0fc |
35 | # Metaclasses are singletons, so we cache them here. |
36 | # there is no need to worry about destruction though |
37 | # because they should die only when the program dies. |
38 | # After all, do package definitions even get reaped? |
587aca23 |
39 | my %METAS; |
40 | |
41 | # means of accessing all the metaclasses that have |
42 | # been initialized thus far (for mugwumps obj browser) |
43 | sub get_all_metaclasses { %METAS } |
44 | sub get_all_metaclass_instances { values %METAS } |
45 | sub get_all_metaclass_names { keys %METAS } |
651955fb |
46 | |
bfe4d0fc |
47 | sub initialize { |
351bd7d4 |
48 | my $class = shift; |
49 | my $package_name = shift; |
22286063 |
50 | (defined $package_name && $package_name && !blessed($package_name)) |
51 | || confess "You must pass a package name and it cannot be blessed"; |
651955fb |
52 | $class->construct_class_instance(':package' => $package_name, @_); |
727919c5 |
53 | } |
54 | |
ff43b9d6 |
55 | sub reinitialize { |
56 | my $class = shift; |
57 | my $package_name = shift; |
58 | (defined $package_name && $package_name && !blessed($package_name)) |
59 | || confess "You must pass a package name and it cannot be blessed"; |
60 | $METAS{$package_name} = undef; |
61 | $class->construct_class_instance(':package' => $package_name, @_); |
6d5355c3 |
62 | } |
ff43b9d6 |
63 | |
727919c5 |
64 | # NOTE: (meta-circularity) |
65 | # this is a special form of &construct_instance |
66 | # (see below), which is used to construct class |
1a7ebbb3 |
67 | # meta-object instances for any Class::MOP::* |
68 | # class. All other classes will use the more |
69 | # normal &construct_instance. |
727919c5 |
70 | sub construct_class_instance { |
351bd7d4 |
71 | my $class = shift; |
651955fb |
72 | my %options = @_; |
73 | my $package_name = $options{':package'}; |
727919c5 |
74 | (defined $package_name && $package_name) |
651955fb |
75 | || confess "You must pass a package name"; |
2d711cc8 |
76 | # NOTE: |
77 | # return the metaclass if we have it cached, |
78 | # and it is still defined (it has not been |
79 | # reaped by DESTROY yet, which can happen |
80 | # annoyingly enough during global destruction) |
2f6d5412 |
81 | return $METAS{$package_name} |
2d711cc8 |
82 | if exists $METAS{$package_name} && defined $METAS{$package_name}; |
373a16ae |
83 | |
84 | # NOTE: |
85 | # we need to deal with the possibility |
86 | # of class immutability here, and then |
87 | # get the name of the class appropriately |
88 | $class = (blessed($class) |
89 | ? ($class->is_immutable |
90 | ? $class->get_mutable_metaclass_name() |
91 | : blessed($class)) |
92 | : $class); |
93 | |
1a7ebbb3 |
94 | $class = blessed($class) || $class; |
550d56db |
95 | # now create the metaclass |
96 | my $meta; |
a5e51f0b |
97 | if ($class =~ /^Class::MOP::Class$/) { |
98 | no strict 'refs'; |
550d56db |
99 | $meta = bless { |
f0480c45 |
100 | # inherited from Class::MOP::Package |
351bd7d4 |
101 | '$:package' => $package_name, |
a5e51f0b |
102 | '%:namespace' => \%{$package_name . '::'}, |
f0480c45 |
103 | # inherited from Class::MOP::Module |
104 | '$:version' => (exists ${$package_name . '::'}{'VERSION'} ? ${$package_name . '::VERSION'} : undef), |
105 | '$:authority' => (exists ${$package_name . '::'}{'AUTHORITY'} ? ${$package_name . '::AUTHORITY'} : undef), |
106 | # defined here ... |
351bd7d4 |
107 | '%:attributes' => {}, |
550d56db |
108 | '$:attribute_metaclass' => $options{':attribute_metaclass'} || 'Class::MOP::Attribute', |
2bab2be6 |
109 | '$:method_metaclass' => $options{':method_metaclass'} || 'Class::MOP::Method', |
857f87a7 |
110 | '$:instance_metaclass' => $options{':instance_metaclass'} || 'Class::MOP::Instance', |
1a7ebbb3 |
111 | } => $class; |
112 | } |
113 | else { |
5f3c057a |
114 | # NOTE: |
115 | # it is safe to use meta here because |
116 | # class will always be a subclass of |
117 | # Class::MOP::Class, which defines meta |
40483095 |
118 | $meta = $class->meta->construct_instance(%options) |
1a7ebbb3 |
119 | } |
a5e51f0b |
120 | |
550d56db |
121 | # and check the metaclass compatibility |
122 | $meta->check_metaclass_compatability(); |
123 | $METAS{$package_name} = $meta; |
77e5fce4 |
124 | # NOTE: |
125 | # we need to weaken any anon classes |
126 | # so that they can call DESTROY properly |
127 | weaken($METAS{$package_name}) |
128 | if $package_name =~ /^$ANON_CLASS_PREFIX/; |
129 | $meta; |
130 | } |
131 | |
550d56db |
132 | sub check_metaclass_compatability { |
133 | my $self = shift; |
134 | |
135 | # this is always okay ... |
d82060fe |
136 | return if blessed($self) eq 'Class::MOP::Class' && |
137 | $self->instance_metaclass eq 'Class::MOP::Instance'; |
550d56db |
138 | |
139 | my @class_list = $self->class_precedence_list; |
140 | shift @class_list; # shift off $self->name |
141 | |
142 | foreach my $class_name (@class_list) { |
96ceced8 |
143 | my $meta = $METAS{$class_name} || next; |
373a16ae |
144 | |
145 | # NOTE: |
146 | # we need to deal with the possibility |
147 | # of class immutability here, and then |
148 | # get the name of the class appropriately |
149 | my $meta_type = ($meta->is_immutable |
150 | ? $meta->get_mutable_metaclass_name() |
151 | : blessed($meta)); |
152 | |
153 | ($self->isa($meta_type)) |
550d56db |
154 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
155 | " is not compatible with the " . |
373a16ae |
156 | $class_name . "->meta => (" . ($meta_type) . ")"; |
f7259199 |
157 | # NOTE: |
158 | # we also need to check that instance metaclasses |
159 | # are compatabile in the same the class. |
160 | ($self->instance_metaclass->isa($meta->instance_metaclass)) |
161 | || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . |
162 | " is not compatible with the " . |
163 | $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; |
550d56db |
164 | } |
fa16e528 |
165 | } |
f7259199 |
166 | } |
8b978dd5 |
167 | |
6d5355c3 |
168 | ## ANON classes |
169 | |
170 | { |
171 | # NOTE: |
172 | # this should be sufficient, if you have a |
173 | # use case where it is not, write a test and |
174 | # I will change it. |
175 | my $ANON_CLASS_SERIAL = 0; |
176 | |
177 | sub create_anon_class { |
178 | my ($class, %options) = @_; |
179 | my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL; |
180 | return $class->create($package_name, '0.00', %options); |
181 | } |
182 | } |
183 | |
184 | # NOTE: |
185 | # this will only get called for |
186 | # anon-classes, all other calls |
187 | # are assumed to occur during |
188 | # global destruction and so don't |
189 | # really need to be handled explicitly |
190 | sub DESTROY { |
191 | my $self = shift; |
192 | return unless $self->name =~ /^$ANON_CLASS_PREFIX/; |
193 | my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/); |
194 | no strict 'refs'; |
195 | foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) { |
196 | delete ${$ANON_CLASS_PREFIX . $serial_id}{$key}; |
197 | } |
198 | delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; |
199 | } |
200 | |
201 | # creating classes with MOP ... |
202 | |
8b978dd5 |
203 | sub create { |
204 | my ($class, $package_name, $package_version, %options) = @_; |
bfe4d0fc |
205 | (defined $package_name && $package_name) |
8b978dd5 |
206 | || confess "You must pass a package name"; |
207 | my $code = "package $package_name;"; |
208 | $code .= "\$$package_name\:\:VERSION = '$package_version';" |
209 | if defined $package_version; |
210 | eval $code; |
211 | confess "creation of $package_name failed : $@" if $@; |
bfe4d0fc |
212 | my $meta = $class->initialize($package_name); |
aa448b16 |
213 | |
214 | $meta->add_method('meta' => sub { |
df7b4119 |
215 | $class->initialize(blessed($_[0]) || $_[0]); |
aa448b16 |
216 | }); |
217 | |
8b978dd5 |
218 | $meta->superclasses(@{$options{superclasses}}) |
219 | if exists $options{superclasses}; |
2eb717d5 |
220 | # NOTE: |
221 | # process attributes first, so that they can |
222 | # install accessors, but locally defined methods |
223 | # can then overwrite them. It is maybe a little odd, but |
224 | # I think this should be the order of things. |
225 | if (exists $options{attributes}) { |
cbd9f942 |
226 | foreach my $attr (@{$options{attributes}}) { |
227 | $meta->add_attribute($attr); |
2eb717d5 |
228 | } |
229 | } |
bfe4d0fc |
230 | if (exists $options{methods}) { |
231 | foreach my $method_name (keys %{$options{methods}}) { |
232 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
233 | } |
2eb717d5 |
234 | } |
8b978dd5 |
235 | return $meta; |
236 | } |
237 | |
7b31baf4 |
238 | ## Attribute readers |
239 | |
240 | # NOTE: |
241 | # all these attribute readers will be bootstrapped |
242 | # away in the Class::MOP bootstrap section |
243 | |
7b31baf4 |
244 | sub get_attribute_map { $_[0]->{'%:attributes'} } |
245 | sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} } |
246 | sub method_metaclass { $_[0]->{'$:method_metaclass'} } |
2bab2be6 |
247 | sub instance_metaclass { $_[0]->{'$:instance_metaclass'} } |
7b31baf4 |
248 | |
c9e77dbb |
249 | # Instance Construction & Cloning |
250 | |
5f3c057a |
251 | sub new_object { |
252 | my $class = shift; |
651955fb |
253 | # NOTE: |
254 | # we need to protect the integrity of the |
255 | # Class::MOP::Class singletons here, so we |
256 | # delegate this to &construct_class_instance |
257 | # which will deal with the singletons |
258 | return $class->construct_class_instance(@_) |
259 | if $class->name->isa('Class::MOP::Class'); |
24869f62 |
260 | return $class->construct_instance(@_); |
5f3c057a |
261 | } |
e16da3e6 |
262 | |
263 | sub construct_instance { |
cbd9f942 |
264 | my ($class, %params) = @_; |
0e76a376 |
265 | my $meta_instance = $class->get_meta_instance(); |
266 | my $instance = $meta_instance->create_instance(); |
c9e77dbb |
267 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
f892c0f0 |
268 | $attr->initialize_instance_slot($meta_instance, $instance, \%params); |
cbd9f942 |
269 | } |
2d711cc8 |
270 | return $instance; |
271 | } |
272 | |
273 | sub get_meta_instance { |
274 | my $class = shift; |
052c2a1a |
275 | return $class->instance_metaclass->new( |
276 | $class, |
277 | $class->compute_all_applicable_attributes() |
278 | ); |
e16da3e6 |
279 | } |
280 | |
5f3c057a |
281 | sub clone_object { |
282 | my $class = shift; |
7b31baf4 |
283 | my $instance = shift; |
651955fb |
284 | (blessed($instance) && $instance->isa($class->name)) |
285 | || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; |
286 | # NOTE: |
287 | # we need to protect the integrity of the |
288 | # Class::MOP::Class singletons here, they |
a740253a |
289 | # should not be cloned. |
651955fb |
290 | return $instance if $instance->isa('Class::MOP::Class'); |
f7259199 |
291 | $class->clone_instance($instance, @_); |
5f3c057a |
292 | } |
293 | |
c9e77dbb |
294 | sub clone_instance { |
651955fb |
295 | my ($class, $instance, %params) = @_; |
296 | (blessed($instance)) |
c9e77dbb |
297 | || confess "You can only clone instances, \$self is not a blessed instance"; |
f7259199 |
298 | my $meta_instance = $class->get_meta_instance(); |
299 | my $clone = $meta_instance->clone_instance($instance); |
11977e43 |
300 | foreach my $key (keys %params) { |
f7259199 |
301 | next unless $meta_instance->is_valid_slot($key); |
302 | $meta_instance->set_slot_value($clone, $key, $params{$key}); |
303 | } |
c9e77dbb |
304 | return $clone; |
305 | } |
306 | |
8b978dd5 |
307 | # Inheritance |
308 | |
309 | sub superclasses { |
310 | my $self = shift; |
8b978dd5 |
311 | if (@_) { |
312 | my @supers = @_; |
9d6dce77 |
313 | @{$self->get_package_symbol('@ISA')} = @supers; |
d82060fe |
314 | # NOTE: |
315 | # we need to check the metaclass |
316 | # compatability here so that we can |
317 | # be sure that the superclass is |
318 | # not potentially creating an issues |
319 | # we don't know about |
320 | $self->check_metaclass_compatability(); |
8b978dd5 |
321 | } |
9d6dce77 |
322 | @{$self->get_package_symbol('@ISA')}; |
8b978dd5 |
323 | } |
324 | |
325 | sub class_precedence_list { |
326 | my $self = shift; |
bfe4d0fc |
327 | # NOTE: |
328 | # We need to check for ciruclar inheirtance here. |
329 | # This will do nothing if all is well, and blow |
330 | # up otherwise. Yes, it's an ugly hack, better |
331 | # suggestions are welcome. |
93b4e576 |
332 | { ($self->name || return)->isa('This is a test for circular inheritance') } |
8c936afc |
333 | # ... and now back to our regularly scheduled program |
8b978dd5 |
334 | ( |
335 | $self->name, |
336 | map { |
f7259199 |
337 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
338 | } $self->superclasses() |
339 | ); |
340 | } |
341 | |
0882828e |
342 | ## Methods |
343 | |
344 | sub add_method { |
345 | my ($self, $method_name, $method) = @_; |
346 | (defined $method_name && $method_name) |
347 | || confess "You must define a method name"; |
a5eca695 |
348 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
349 | ('CODE' eq (reftype($method) || '')) |
0882828e |
350 | || confess "Your code block must be a CODE reference"; |
351 | my $full_method_name = ($self->name . '::' . $method_name); |
de19f115 |
352 | |
9d6dce77 |
353 | # FIXME: |
354 | # dont bless subs, its bad mkay |
2d711cc8 |
355 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
356 | |
9d6dce77 |
357 | $self->add_package_symbol("&${method_name}" => subname $full_method_name => $method); |
0882828e |
358 | } |
359 | |
a4258ffd |
360 | { |
2d711cc8 |
361 | my $fetch_and_prepare_method = sub { |
362 | my ($self, $method_name) = @_; |
363 | # fetch it locally |
364 | my $method = $self->get_method($method_name); |
365 | # if we dont have local ... |
366 | unless ($method) { |
195f5bf8 |
367 | # try to find the next method |
368 | $method = $self->find_next_method_by_name($method_name); |
369 | # die if it does not exist |
370 | (defined $method) |
2d711cc8 |
371 | || confess "The method '$method_name' is not found in the inherience hierarchy for this class"; |
195f5bf8 |
372 | # and now make sure to wrap it |
373 | # even if it is already wrapped |
374 | # because we need a new sub ref |
2d711cc8 |
375 | $method = Class::MOP::Method::Wrapped->wrap($method); |
195f5bf8 |
376 | } |
377 | else { |
378 | # now make sure we wrap it properly |
379 | $method = Class::MOP::Method::Wrapped->wrap($method) |
380 | unless $method->isa('Class::MOP::Method::Wrapped'); |
381 | } |
382 | $self->add_method($method_name => $method); |
2d711cc8 |
383 | return $method; |
384 | }; |
385 | |
386 | sub add_before_method_modifier { |
387 | my ($self, $method_name, $method_modifier) = @_; |
388 | (defined $method_name && $method_name) |
389 | || confess "You must pass in a method name"; |
390 | my $method = $fetch_and_prepare_method->($self, $method_name); |
391 | $method->add_before_modifier(subname ':before' => $method_modifier); |
392 | } |
393 | |
394 | sub add_after_method_modifier { |
395 | my ($self, $method_name, $method_modifier) = @_; |
396 | (defined $method_name && $method_name) |
397 | || confess "You must pass in a method name"; |
398 | my $method = $fetch_and_prepare_method->($self, $method_name); |
399 | $method->add_after_modifier(subname ':after' => $method_modifier); |
400 | } |
401 | |
402 | sub add_around_method_modifier { |
403 | my ($self, $method_name, $method_modifier) = @_; |
404 | (defined $method_name && $method_name) |
405 | || confess "You must pass in a method name"; |
406 | my $method = $fetch_and_prepare_method->($self, $method_name); |
407 | $method->add_around_modifier(subname ':around' => $method_modifier); |
408 | } |
a4258ffd |
409 | |
8c936afc |
410 | # NOTE: |
411 | # the methods above used to be named like this: |
412 | # ${pkg}::${method}:(before|after|around) |
413 | # but this proved problematic when using one modifier |
414 | # to wrap multiple methods (something which is likely |
415 | # to happen pretty regularly IMO). So instead of naming |
416 | # it like this, I have chosen to just name them purely |
417 | # with their modifier names, like so: |
418 | # :(before|after|around) |
419 | # The fact is that in a stack trace, it will be fairly |
420 | # evident from the context what method they are attached |
421 | # to, and so don't need the fully qualified name. |
ee5e71d4 |
422 | } |
423 | |
663f8198 |
424 | sub alias_method { |
425 | my ($self, $method_name, $method) = @_; |
426 | (defined $method_name && $method_name) |
427 | || confess "You must define a method name"; |
428 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
429 | ('CODE' eq (reftype($method) || '')) |
663f8198 |
430 | || confess "Your code block must be a CODE reference"; |
de19f115 |
431 | |
9d6dce77 |
432 | # FIXME: |
433 | # dont bless subs, its bad mkay |
2d711cc8 |
434 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
663f8198 |
435 | |
9d6dce77 |
436 | $self->add_package_symbol("&${method_name}" => $method); |
663f8198 |
437 | } |
438 | |
16e960bd |
439 | sub find_method_by_name { |
9d6dce77 |
440 | my ($self, $method_name) = @_; |
441 | return $self->name->can($method_name); |
16e960bd |
442 | } |
443 | |
de19f115 |
444 | sub has_method { |
445 | my ($self, $method_name) = @_; |
446 | (defined $method_name && $method_name) |
447 | || confess "You must define a method name"; |
0882828e |
448 | |
9d6dce77 |
449 | return 0 if !$self->has_package_symbol("&${method_name}"); |
450 | my $method = $self->get_package_symbol("&${method_name}"); |
96ceced8 |
451 | return 0 if (svref_2object($method)->GV->STASH->NAME || '') ne $self->name && |
2d711cc8 |
452 | (svref_2object($method)->GV->NAME || '') ne '__ANON__'; |
16e960bd |
453 | |
9d6dce77 |
454 | # FIXME: |
455 | # dont bless subs, its bad mkay |
456 | $self->method_metaclass->wrap($method) unless blessed($method); |
457 | |
de19f115 |
458 | return 1; |
0882828e |
459 | } |
460 | |
461 | sub get_method { |
c9b8b7f9 |
462 | my ($self, $method_name) = @_; |
0882828e |
463 | (defined $method_name && $method_name) |
464 | || confess "You must define a method name"; |
465 | |
2d711cc8 |
466 | return unless $self->has_method($method_name); |
9d6dce77 |
467 | |
468 | return $self->get_package_symbol("&${method_name}"); |
c9b8b7f9 |
469 | } |
470 | |
471 | sub remove_method { |
472 | my ($self, $method_name) = @_; |
473 | (defined $method_name && $method_name) |
474 | || confess "You must define a method name"; |
475 | |
476 | my $removed_method = $self->get_method($method_name); |
477 | |
9d6dce77 |
478 | $self->remove_package_symbol("&${method_name}") |
c9b8b7f9 |
479 | if defined $removed_method; |
480 | |
481 | return $removed_method; |
482 | } |
483 | |
484 | sub get_method_list { |
485 | my $self = shift; |
9d6dce77 |
486 | grep { $self->has_method($_) } $self->list_all_package_symbols; |
a5eca695 |
487 | } |
488 | |
489 | sub compute_all_applicable_methods { |
490 | my $self = shift; |
491 | my @methods; |
492 | # keep a record of what we have seen |
493 | # here, this will handle all the |
494 | # inheritence issues because we are |
495 | # using the &class_precedence_list |
496 | my (%seen_class, %seen_method); |
497 | foreach my $class ($self->class_precedence_list()) { |
498 | next if $seen_class{$class}; |
499 | $seen_class{$class}++; |
500 | # fetch the meta-class ... |
501 | my $meta = $self->initialize($class); |
502 | foreach my $method_name ($meta->get_method_list()) { |
503 | next if exists $seen_method{$method_name}; |
504 | $seen_method{$method_name}++; |
505 | push @methods => { |
506 | name => $method_name, |
507 | class => $class, |
508 | code => $meta->get_method($method_name) |
509 | }; |
510 | } |
511 | } |
512 | return @methods; |
513 | } |
514 | |
a5eca695 |
515 | sub find_all_methods_by_name { |
516 | my ($self, $method_name) = @_; |
517 | (defined $method_name && $method_name) |
518 | || confess "You must define a method name to find"; |
519 | my @methods; |
520 | # keep a record of what we have seen |
521 | # here, this will handle all the |
522 | # inheritence issues because we are |
523 | # using the &class_precedence_list |
524 | my %seen_class; |
525 | foreach my $class ($self->class_precedence_list()) { |
526 | next if $seen_class{$class}; |
527 | $seen_class{$class}++; |
528 | # fetch the meta-class ... |
96ceced8 |
529 | my $meta = $self->initialize($class); |
a5eca695 |
530 | push @methods => { |
531 | name => $method_name, |
532 | class => $class, |
533 | code => $meta->get_method($method_name) |
534 | } if $meta->has_method($method_name); |
535 | } |
536 | return @methods; |
8b978dd5 |
537 | } |
538 | |
96ceced8 |
539 | sub find_next_method_by_name { |
540 | my ($self, $method_name) = @_; |
541 | (defined $method_name && $method_name) |
2d711cc8 |
542 | || confess "You must define a method name to find"; |
96ceced8 |
543 | # keep a record of what we have seen |
544 | # here, this will handle all the |
545 | # inheritence issues because we are |
546 | # using the &class_precedence_list |
547 | my %seen_class; |
2d711cc8 |
548 | my @cpl = $self->class_precedence_list(); |
549 | shift @cpl; # discard ourselves |
96ceced8 |
550 | foreach my $class (@cpl) { |
551 | next if $seen_class{$class}; |
552 | $seen_class{$class}++; |
553 | # fetch the meta-class ... |
554 | my $meta = $self->initialize($class); |
2d711cc8 |
555 | return $meta->get_method($method_name) |
556 | if $meta->has_method($method_name); |
96ceced8 |
557 | } |
2d711cc8 |
558 | return; |
96ceced8 |
559 | } |
560 | |
552e3d24 |
561 | ## Attributes |
562 | |
e16da3e6 |
563 | sub add_attribute { |
2e41896e |
564 | my $self = shift; |
565 | # either we have an attribute object already |
566 | # or we need to create one from the args provided |
567 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
568 | # make sure it is derived from the correct type though |
569 | ($attribute->isa('Class::MOP::Attribute')) |
570 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
9ec169fe |
571 | $attribute->attach_to_class($self); |
2d711cc8 |
572 | $attribute->install_accessors(); |
291073fc |
573 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
574 | } |
575 | |
576 | sub has_attribute { |
577 | my ($self, $attribute_name) = @_; |
578 | (defined $attribute_name && $attribute_name) |
579 | || confess "You must define an attribute name"; |
291073fc |
580 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
e16da3e6 |
581 | } |
582 | |
583 | sub get_attribute { |
584 | my ($self, $attribute_name) = @_; |
585 | (defined $attribute_name && $attribute_name) |
586 | || confess "You must define an attribute name"; |
f7259199 |
587 | return $self->get_attribute_map->{$attribute_name} |
588 | if $self->has_attribute($attribute_name); |
22286063 |
589 | return; |
e16da3e6 |
590 | } |
591 | |
592 | sub remove_attribute { |
593 | my ($self, $attribute_name) = @_; |
594 | (defined $attribute_name && $attribute_name) |
595 | || confess "You must define an attribute name"; |
7b31baf4 |
596 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
597 | return unless defined $removed_attribute; |
598 | delete $self->get_attribute_map->{$attribute_name}; |
2d711cc8 |
599 | $removed_attribute->remove_accessors(); |
2d711cc8 |
600 | $removed_attribute->detach_from_class(); |
e16da3e6 |
601 | return $removed_attribute; |
602 | } |
603 | |
604 | sub get_attribute_list { |
605 | my $self = shift; |
f7259199 |
606 | keys %{$self->get_attribute_map}; |
e16da3e6 |
607 | } |
608 | |
609 | sub compute_all_applicable_attributes { |
610 | my $self = shift; |
611 | my @attrs; |
612 | # keep a record of what we have seen |
613 | # here, this will handle all the |
614 | # inheritence issues because we are |
615 | # using the &class_precedence_list |
616 | my (%seen_class, %seen_attr); |
617 | foreach my $class ($self->class_precedence_list()) { |
618 | next if $seen_class{$class}; |
619 | $seen_class{$class}++; |
620 | # fetch the meta-class ... |
f7259199 |
621 | my $meta = $self->initialize($class); |
e16da3e6 |
622 | foreach my $attr_name ($meta->get_attribute_list()) { |
623 | next if exists $seen_attr{$attr_name}; |
624 | $seen_attr{$attr_name}++; |
c9e77dbb |
625 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
626 | } |
627 | } |
628 | return @attrs; |
629 | } |
2eb717d5 |
630 | |
058c1cf5 |
631 | sub find_attribute_by_name { |
632 | my ($self, $attr_name) = @_; |
633 | # keep a record of what we have seen |
634 | # here, this will handle all the |
635 | # inheritence issues because we are |
636 | # using the &class_precedence_list |
637 | my %seen_class; |
638 | foreach my $class ($self->class_precedence_list()) { |
639 | next if $seen_class{$class}; |
640 | $seen_class{$class}++; |
641 | # fetch the meta-class ... |
642 | my $meta = $self->initialize($class); |
643 | return $meta->get_attribute($attr_name) |
644 | if $meta->has_attribute($attr_name); |
645 | } |
646 | return; |
647 | } |
648 | |
857f87a7 |
649 | ## Class closing |
650 | |
651 | sub is_mutable { 1 } |
652 | sub is_immutable { 0 } |
653 | |
654 | sub make_immutable { |
c0cbf4d9 |
655 | return Class::MOP::Class::Immutable->make_metaclass_immutable(@_); |
857f87a7 |
656 | } |
657 | |
8b978dd5 |
658 | 1; |
659 | |
660 | __END__ |
661 | |
662 | =pod |
663 | |
664 | =head1 NAME |
665 | |
666 | Class::MOP::Class - Class Meta Object |
667 | |
668 | =head1 SYNOPSIS |
669 | |
8c936afc |
670 | # assuming that class Foo |
671 | # has been defined, you can |
672 | |
fe122940 |
673 | # use this for introspection ... |
674 | |
fe122940 |
675 | # add a method to Foo ... |
676 | Foo->meta->add_method('bar' => sub { ... }) |
677 | |
678 | # get a list of all the classes searched |
679 | # the method dispatcher in the correct order |
680 | Foo->meta->class_precedence_list() |
681 | |
682 | # remove a method from Foo |
683 | Foo->meta->remove_method('bar'); |
684 | |
685 | # or use this to actually create classes ... |
686 | |
687 | Class::MOP::Class->create('Bar' => '0.01' => ( |
688 | superclasses => [ 'Foo' ], |
689 | attributes => [ |
690 | Class::MOP:::Attribute->new('$bar'), |
691 | Class::MOP:::Attribute->new('$baz'), |
692 | ], |
693 | methods => { |
694 | calculate_bar => sub { ... }, |
695 | construct_baz => sub { ... } |
696 | } |
697 | )); |
698 | |
8b978dd5 |
699 | =head1 DESCRIPTION |
700 | |
fe122940 |
701 | This is the largest and currently most complex part of the Perl 5 |
702 | meta-object protocol. It controls the introspection and |
703 | manipulation of Perl 5 classes (and it can create them too). The |
704 | best way to understand what this module can do, is to read the |
705 | documentation for each of it's methods. |
706 | |
552e3d24 |
707 | =head1 METHODS |
708 | |
2eb717d5 |
709 | =head2 Self Introspection |
710 | |
711 | =over 4 |
712 | |
713 | =item B<meta> |
714 | |
fe122940 |
715 | This will return a B<Class::MOP::Class> instance which is related |
716 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
717 | introspect itself. |
718 | |
719 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
720 | bootstrap this module by installing a number of attribute meta-objects |
721 | into it's metaclass. This will allow this class to reap all the benifits |
722 | of the MOP when subclassing it. |
2eb717d5 |
723 | |
587aca23 |
724 | =item B<get_all_metaclasses> |
725 | |
726 | This will return an hash of all the metaclass instances that have |
727 | been cached by B<Class::MOP::Class> keyed by the package name. |
728 | |
729 | =item B<get_all_metaclass_instances> |
730 | |
731 | This will return an array of all the metaclass instances that have |
732 | been cached by B<Class::MOP::Class>. |
733 | |
734 | =item B<get_all_metaclass_names> |
735 | |
736 | This will return an array of all the metaclass names that have |
737 | been cached by B<Class::MOP::Class>. |
738 | |
2eb717d5 |
739 | =back |
740 | |
552e3d24 |
741 | =head2 Class construction |
742 | |
a2e85e6c |
743 | These methods will handle creating B<Class::MOP::Class> objects, |
744 | which can be used to both create new classes, and analyze |
745 | pre-existing classes. |
552e3d24 |
746 | |
747 | This module will internally store references to all the instances |
748 | you create with these methods, so that they do not need to be |
749 | created any more than nessecary. Basically, they are singletons. |
750 | |
751 | =over 4 |
752 | |
753 | =item B<create ($package_name, ?$package_version, |
a2e85e6c |
754 | superclasses =E<gt> ?@superclasses, |
755 | methods =E<gt> ?%methods, |
756 | attributes =E<gt> ?%attributes)> |
552e3d24 |
757 | |
a2e85e6c |
758 | This returns a B<Class::MOP::Class> object, bringing the specified |
552e3d24 |
759 | C<$package_name> into existence and adding any of the |
760 | C<$package_version>, C<@superclasses>, C<%methods> and C<%attributes> |
761 | to it. |
762 | |
587aca23 |
763 | =item B<create_anon_class (superclasses =E<gt> ?@superclasses, |
764 | methods =E<gt> ?%methods, |
765 | attributes =E<gt> ?%attributes)> |
766 | |
767 | This will create an anonymous class, it works much like C<create> but |
768 | it does not need a C<$package_name>. Instead it will create a suitably |
769 | unique package name for you to stash things into. |
770 | |
66b3dded |
771 | =item B<initialize ($package_name, %options)> |
552e3d24 |
772 | |
a2e85e6c |
773 | This initializes and returns returns a B<Class::MOP::Class> object |
774 | for a given a C<$package_name>. |
775 | |
66b3dded |
776 | =item B<reinitialize ($package_name, %options)> |
777 | |
778 | This removes the old metaclass, and creates a new one in it's place. |
779 | Do B<not> use this unless you really know what you are doing, it could |
780 | very easily make a very large mess of your program. |
781 | |
651955fb |
782 | =item B<construct_class_instance (%options)> |
a2e85e6c |
783 | |
784 | This will construct an instance of B<Class::MOP::Class>, it is |
785 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
786 | to use C<construct_instance> once all the bootstrapping is done. This |
787 | method is used internally by C<initialize> and should never be called |
788 | from outside of that method really. |
552e3d24 |
789 | |
550d56db |
790 | =item B<check_metaclass_compatability> |
791 | |
792 | This method is called as the very last thing in the |
793 | C<construct_class_instance> method. This will check that the |
794 | metaclass you are creating is compatible with the metaclasses of all |
795 | your ancestors. For more inforamtion about metaclass compatibility |
796 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
797 | |
552e3d24 |
798 | =back |
799 | |
c9e77dbb |
800 | =head2 Object instance construction and cloning |
a2e85e6c |
801 | |
c9e77dbb |
802 | These methods are B<entirely optional>, it is up to you whether you want |
803 | to use them or not. |
552e3d24 |
804 | |
805 | =over 4 |
806 | |
2bab2be6 |
807 | =item B<instance_metaclass> |
808 | |
2d711cc8 |
809 | =item B<get_meta_instance> |
810 | |
5f3c057a |
811 | =item B<new_object (%params)> |
812 | |
813 | This is a convience method for creating a new object of the class, and |
814 | blessing it into the appropriate package as well. Ideally your class |
815 | would call a C<new> this method like so: |
816 | |
817 | sub MyClass::new { |
818 | my ($class, %param) = @_; |
819 | $class->meta->new_object(%params); |
820 | } |
821 | |
822 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
823 | but that is considered bad style, so we do not do that. |
824 | |
cbd9f942 |
825 | =item B<construct_instance (%params)> |
552e3d24 |
826 | |
c9e77dbb |
827 | This method is used to construct an instace structure suitable for |
828 | C<bless>-ing into your package of choice. It works in conjunction |
829 | with the Attribute protocol to collect all applicable attributes. |
830 | |
cbd9f942 |
831 | This will construct and instance using a HASH ref as storage |
552e3d24 |
832 | (currently only HASH references are supported). This will collect all |
a2e85e6c |
833 | the applicable attributes and layout out the fields in the HASH ref, |
834 | it will then initialize them using either use the corresponding key |
835 | in C<%params> or any default value or initializer found in the |
836 | attribute meta-object. |
727919c5 |
837 | |
5f3c057a |
838 | =item B<clone_object ($instance, %params)> |
839 | |
840 | This is a convience method for cloning an object instance, then |
19d4b5b8 |
841 | blessing it into the appropriate package. This method will call |
842 | C<clone_instance>, which performs a shallow copy of the object, |
843 | see that methods documentation for more details. Ideally your |
844 | class would call a C<clone> this method like so: |
5f3c057a |
845 | |
846 | sub MyClass::clone { |
847 | my ($self, %param) = @_; |
848 | $self->meta->clone_object($self, %params); |
849 | } |
850 | |
851 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
852 | but that is considered bad style, so we do not do that. |
853 | |
c9e77dbb |
854 | =item B<clone_instance($instance, %params)> |
855 | |
856 | This method is a compliment of C<construct_instance> (which means if |
19d4b5b8 |
857 | you override C<construct_instance>, you need to override this one too), |
858 | and clones the instance shallowly. |
a27ae83f |
859 | |
860 | The cloned structure returned is (like with C<construct_instance>) an |
861 | unC<bless>ed HASH reference, it is your responsibility to then bless |
862 | this cloned structure into the right class (which C<clone_object> will |
863 | do for you). |
c9e77dbb |
864 | |
19d4b5b8 |
865 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
866 | as opposed to the deep cloning implemented in prior versions. After much |
867 | thought, research and discussion, I have decided that anything but basic |
868 | shallow cloning is outside the scope of the meta-object protocol. I |
869 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
870 | is too I<context-specific> to be part of the MOP. |
871 | |
552e3d24 |
872 | =back |
873 | |
874 | =head2 Informational |
875 | |
876 | =over 4 |
877 | |
878 | =item B<name> |
879 | |
a2e85e6c |
880 | This is a read-only attribute which returns the package name for the |
881 | given B<Class::MOP::Class> instance. |
552e3d24 |
882 | |
883 | =item B<version> |
884 | |
885 | This is a read-only attribute which returns the C<$VERSION> of the |
a2e85e6c |
886 | package for the given B<Class::MOP::Class> instance. |
552e3d24 |
887 | |
888 | =back |
889 | |
890 | =head2 Inheritance Relationships |
891 | |
892 | =over 4 |
893 | |
894 | =item B<superclasses (?@superclasses)> |
895 | |
896 | This is a read-write attribute which represents the superclass |
a2e85e6c |
897 | relationships of the class the B<Class::MOP::Class> instance is |
898 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
899 | |
343203ee |
900 | B<NOTE:> |
901 | Perl will occasionally perform some C<@ISA> and method caching, if |
902 | you decide to change your superclass relationship at runtime (which |
903 | is quite insane and very much not recommened), then you should be |
904 | aware of this and the fact that this module does not make any |
905 | attempt to address this issue. |
906 | |
552e3d24 |
907 | =item B<class_precedence_list> |
908 | |
a2e85e6c |
909 | This computes the a list of all the class's ancestors in the same order |
910 | in which method dispatch will be done. This is similair to |
911 | what B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
912 | |
913 | =back |
914 | |
915 | =head2 Methods |
916 | |
917 | =over 4 |
918 | |
2e41896e |
919 | =item B<method_metaclass> |
920 | |
552e3d24 |
921 | =item B<add_method ($method_name, $method)> |
922 | |
923 | This will take a C<$method_name> and CODE reference to that |
a2e85e6c |
924 | C<$method> and install it into the class's package. |
552e3d24 |
925 | |
a2e85e6c |
926 | B<NOTE>: |
927 | This does absolutely nothing special to C<$method> |
552e3d24 |
928 | other than use B<Sub::Name> to make sure it is tagged with the |
929 | correct name, and therefore show up correctly in stack traces and |
930 | such. |
931 | |
663f8198 |
932 | =item B<alias_method ($method_name, $method)> |
933 | |
934 | This will take a C<$method_name> and CODE reference to that |
935 | C<$method> and alias the method into the class's package. |
936 | |
937 | B<NOTE>: |
938 | Unlike C<add_method>, this will B<not> try to name the |
939 | C<$method> using B<Sub::Name>, it only aliases the method in |
940 | the class's package. |
941 | |
552e3d24 |
942 | =item B<has_method ($method_name)> |
943 | |
a2e85e6c |
944 | This just provides a simple way to check if the class implements |
552e3d24 |
945 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
946 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
947 | |
948 | This will correctly handle functions defined outside of the package |
949 | that use a fully qualified name (C<sub Package::name { ... }>). |
950 | |
951 | This will correctly handle functions renamed with B<Sub::Name> and |
952 | installed using the symbol tables. However, if you are naming the |
953 | subroutine outside of the package scope, you must use the fully |
954 | qualified name, including the package name, for C<has_method> to |
955 | correctly identify it. |
956 | |
957 | This will attempt to correctly ignore functions imported from other |
958 | packages using B<Exporter>. It breaks down if the function imported |
959 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
960 | may be a valid method being applied to the class. |
961 | |
962 | In short, this method cannot always be trusted to determine if the |
963 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
964 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
965 | |
966 | =item B<get_method ($method_name)> |
967 | |
968 | This will return a CODE reference of the specified C<$method_name>, |
969 | or return undef if that method does not exist. |
970 | |
16e960bd |
971 | =item B<find_method_by_name ($method_name> |
972 | |
973 | This will return a CODE reference of the specified C<$method_name>, |
974 | or return undef if that method does not exist. |
975 | |
976 | Unlike C<get_method> this will also look in the superclasses. |
977 | |
552e3d24 |
978 | =item B<remove_method ($method_name)> |
979 | |
a2e85e6c |
980 | This will attempt to remove a given C<$method_name> from the class. |
552e3d24 |
981 | It will return the CODE reference that it has removed, and will |
982 | attempt to use B<Sub::Name> to clear the methods associated name. |
983 | |
984 | =item B<get_method_list> |
985 | |
986 | This will return a list of method names for all I<locally> defined |
987 | methods. It does B<not> provide a list of all applicable methods, |
988 | including any inherited ones. If you want a list of all applicable |
989 | methods, use the C<compute_all_applicable_methods> method. |
990 | |
991 | =item B<compute_all_applicable_methods> |
992 | |
a2e85e6c |
993 | This will return a list of all the methods names this class will |
994 | respond to, taking into account inheritance. The list will be a list of |
552e3d24 |
995 | HASH references, each one containing the following information; method |
996 | name, the name of the class in which the method lives and a CODE |
997 | reference for the actual method. |
998 | |
999 | =item B<find_all_methods_by_name ($method_name)> |
1000 | |
1001 | This will traverse the inheritence hierarchy and locate all methods |
1002 | with a given C<$method_name>. Similar to |
1003 | C<compute_all_applicable_methods> it returns a list of HASH references |
1004 | with the following information; method name (which will always be the |
1005 | same as C<$method_name>), the name of the class in which the method |
1006 | lives and a CODE reference for the actual method. |
1007 | |
1008 | The list of methods produced is a distinct list, meaning there are no |
1009 | duplicates in it. This is especially useful for things like object |
1010 | initialization and destruction where you only want the method called |
1011 | once, and in the correct order. |
1012 | |
96ceced8 |
1013 | =item B<find_next_method_by_name ($method_name)> |
1014 | |
1015 | This will return the first method to match a given C<$method_name> in |
1016 | the superclasses, this is basically equivalent to calling |
1017 | C<SUPER::$method_name>, but it can be dispatched at runtime. |
1018 | |
552e3d24 |
1019 | =back |
1020 | |
a4258ffd |
1021 | =head2 Method Modifiers |
1022 | |
96ceced8 |
1023 | Method modifiers are a concept borrowed from CLOS, in which a method |
1024 | can be wrapped with I<before>, I<after> and I<around> method modifiers |
1025 | that will be called everytime the method is called. |
1026 | |
1027 | =head3 How method modifiers work? |
1028 | |
1029 | Method modifiers work by wrapping the original method and then replacing |
1030 | it in the classes symbol table. The wrappers will handle calling all the |
1031 | modifiers in the appropariate orders and preserving the calling context |
1032 | for the original method. |
1033 | |
1034 | Each method modifier serves a particular purpose, which may not be |
1035 | obvious to users of other method wrapping modules. To start with, the |
1036 | return values of I<before> and I<after> modifiers are ignored. This is |
1037 | because thier purpose is B<not> to filter the input and output of the |
1038 | primary method (this is done with an I<around> modifier). This may seem |
1039 | like an odd restriction to some, but doing this allows for simple code |
1040 | to be added at the begining or end of a method call without jeapordizing |
1041 | the normal functioning of the primary method or placing any extra |
1042 | responsibility on the code of the modifier. Of course if you have more |
1043 | complex needs, then use the I<around> modifier, which uses a variation |
1044 | of continutation passing style to allow for a high degree of flexibility. |
1045 | |
1046 | Before and around modifiers are called in last-defined-first-called order, |
1047 | while after modifiers are called in first-defined-first-called order. So |
1048 | the call tree might looks something like this: |
1049 | |
1050 | before 2 |
1051 | before 1 |
1052 | around 2 |
1053 | around 1 |
1054 | primary |
1055 | after 1 |
1056 | after 2 |
1057 | |
1058 | To see examples of using method modifiers, see the following examples |
1059 | included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>, |
1060 | F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a |
1061 | classic CLOS usage example in the test F<017_add_method_modifier.t>. |
1062 | |
1063 | =head3 What is the performance impact? |
1064 | |
1065 | Of course there is a performance cost associated with method modifiers, |
1066 | but we have made every effort to make that cost be directly proportional |
1067 | to the amount of modifier features you utilize. |
1068 | |
1069 | The wrapping method does it's best to B<only> do as much work as it |
1070 | absolutely needs to. In order to do this we have moved some of the |
1071 | performance costs to set-up time, where they are easier to amortize. |
1072 | |
1073 | All this said, my benchmarks have indicated the following: |
1074 | |
1075 | simple wrapper with no modifiers 100% slower |
1076 | simple wrapper with simple before modifier 400% slower |
1077 | simple wrapper with simple after modifier 450% slower |
1078 | simple wrapper with simple around modifier 500-550% slower |
1079 | simple wrapper with all 3 modifiers 1100% slower |
1080 | |
1081 | These numbers may seem daunting, but you must remember, every feature |
1082 | comes with some cost. To put things in perspective, just doing a simple |
1083 | C<AUTOLOAD> which does nothing but extract the name of the method called |
1084 | and return it costs about 400% over a normal method call. |
1085 | |
a4258ffd |
1086 | =over 4 |
1087 | |
1088 | =item B<add_before_method_modifier ($method_name, $code)> |
1089 | |
96ceced8 |
1090 | This will wrap the method at C<$method_name> and the supplied C<$code> |
1091 | will be passed the C<@_> arguments, and called before the original |
1092 | method is called. As specified above, the return value of the I<before> |
1093 | method modifiers is ignored, and it's ability to modify C<@_> is |
1094 | fairly limited. If you need to do either of these things, use an |
1095 | C<around> method modifier. |
1096 | |
a4258ffd |
1097 | =item B<add_after_method_modifier ($method_name, $code)> |
1098 | |
96ceced8 |
1099 | This will wrap the method at C<$method_name> so that the original |
1100 | method will be called, it's return values stashed, and then the |
1101 | supplied C<$code> will be passed the C<@_> arguments, and called. |
1102 | As specified above, the return value of the I<after> method |
1103 | modifiers is ignored, and it cannot modify the return values of |
1104 | the original method. If you need to do either of these things, use an |
1105 | C<around> method modifier. |
1106 | |
a4258ffd |
1107 | =item B<add_around_method_modifier ($method_name, $code)> |
1108 | |
96ceced8 |
1109 | This will wrap the method at C<$method_name> so that C<$code> |
1110 | will be called and passed the original method as an extra argument |
1111 | at the begining of the C<@_> argument list. This is a variation of |
1112 | continuation passing style, where the function prepended to C<@_> |
1113 | can be considered a continuation. It is up to C<$code> if it calls |
1114 | the original method or not, there is no restriction on what the |
1115 | C<$code> can or cannot do. |
1116 | |
a4258ffd |
1117 | =back |
1118 | |
552e3d24 |
1119 | =head2 Attributes |
1120 | |
1121 | It should be noted that since there is no one consistent way to define |
1122 | the attributes of a class in Perl 5. These methods can only work with |
1123 | the information given, and can not easily discover information on |
a2e85e6c |
1124 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
1125 | |
1126 | =over 4 |
1127 | |
2e41896e |
1128 | =item B<attribute_metaclass> |
1129 | |
7b31baf4 |
1130 | =item B<get_attribute_map> |
1131 | |
552e3d24 |
1132 | =item B<add_attribute ($attribute_name, $attribute_meta_object)> |
1133 | |
a2e85e6c |
1134 | This stores a C<$attribute_meta_object> in the B<Class::MOP::Class> |
1135 | instance associated with the given class, and associates it with |
1136 | the C<$attribute_name>. Unlike methods, attributes within the MOP |
1137 | are stored as meta-information only. They will be used later to |
1138 | construct instances from (see C<construct_instance> above). |
552e3d24 |
1139 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
1140 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
1141 | section. |
1142 | |
1143 | It should be noted that any accessor, reader/writer or predicate |
1144 | methods which the C<$attribute_meta_object> has will be installed |
1145 | into the class at this time. |
552e3d24 |
1146 | |
1147 | =item B<has_attribute ($attribute_name)> |
1148 | |
a2e85e6c |
1149 | Checks to see if this class has an attribute by the name of |
552e3d24 |
1150 | C<$attribute_name> and returns a boolean. |
1151 | |
1152 | =item B<get_attribute ($attribute_name)> |
1153 | |
1154 | Returns the attribute meta-object associated with C<$attribute_name>, |
1155 | if none is found, it will return undef. |
1156 | |
1157 | =item B<remove_attribute ($attribute_name)> |
1158 | |
1159 | This will remove the attribute meta-object stored at |
1160 | C<$attribute_name>, then return the removed attribute meta-object. |
1161 | |
a2e85e6c |
1162 | B<NOTE:> |
1163 | Removing an attribute will only affect future instances of |
552e3d24 |
1164 | the class, it will not make any attempt to remove the attribute from |
1165 | any existing instances of the class. |
1166 | |
a2e85e6c |
1167 | It should be noted that any accessor, reader/writer or predicate |
1168 | methods which the attribute meta-object stored at C<$attribute_name> |
1169 | has will be removed from the class at this time. This B<will> make |
1170 | these attributes somewhat inaccessable in previously created |
1171 | instances. But if you are crazy enough to do this at runtime, then |
1172 | you are crazy enough to deal with something like this :). |
1173 | |
552e3d24 |
1174 | =item B<get_attribute_list> |
1175 | |
1176 | This returns a list of attribute names which are defined in the local |
1177 | class. If you want a list of all applicable attributes for a class, |
1178 | use the C<compute_all_applicable_attributes> method. |
1179 | |
1180 | =item B<compute_all_applicable_attributes> |
1181 | |
c9e77dbb |
1182 | This will traverse the inheritance heirachy and return a list of all |
1183 | the applicable attributes for this class. It does not construct a |
1184 | HASH reference like C<compute_all_applicable_methods> because all |
1185 | that same information is discoverable through the attribute |
1186 | meta-object itself. |
552e3d24 |
1187 | |
058c1cf5 |
1188 | =item B<find_attribute_by_name ($attr_name)> |
1189 | |
1190 | This method will traverse the inheritance heirachy and find the |
1191 | first attribute whose name matches C<$attr_name>, then return it. |
1192 | It will return undef if nothing is found. |
1193 | |
552e3d24 |
1194 | =back |
1195 | |
52e8a34c |
1196 | =head2 Package Variables |
1197 | |
1198 | Since Perl's classes are built atop the Perl package system, it is |
1199 | fairly common to use package scoped variables for things like static |
1200 | class variables. The following methods are convience methods for |
1201 | the creation and inspection of package scoped variables. |
1202 | |
1203 | =over 4 |
1204 | |
58d75218 |
1205 | =item B<add_package_symbol ($variable_name, ?$initial_value)> |
52e8a34c |
1206 | |
1207 | Given a C<$variable_name>, which must contain a leading sigil, this |
1208 | method will create that variable within the package which houses the |
1209 | class. It also takes an optional C<$initial_value>, which must be a |
1210 | reference of the same type as the sigil of the C<$variable_name> |
1211 | implies. |
1212 | |
58d75218 |
1213 | =item B<get_package_symbol ($variable_name)> |
52e8a34c |
1214 | |
1215 | This will return a reference to the package variable in |
1216 | C<$variable_name>. |
1217 | |
58d75218 |
1218 | =item B<has_package_symbol ($variable_name)> |
52e8a34c |
1219 | |
1220 | Returns true (C<1>) if there is a package variable defined for |
1221 | C<$variable_name>, and false (C<0>) otherwise. |
1222 | |
58d75218 |
1223 | =item B<remove_package_symbol ($variable_name)> |
52e8a34c |
1224 | |
1225 | This will attempt to remove the package variable at C<$variable_name>. |
1226 | |
1227 | =back |
1228 | |
857f87a7 |
1229 | =head2 Class closing |
1230 | |
1231 | =over 4 |
1232 | |
1233 | =item B<is_mutable> |
1234 | |
1235 | =item B<is_immutable> |
1236 | |
1237 | =item B<make_immutable> |
1238 | |
1239 | =back |
1240 | |
1a09d9cc |
1241 | =head1 AUTHORS |
8b978dd5 |
1242 | |
a2e85e6c |
1243 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
1244 | |
1a09d9cc |
1245 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
1246 | |
8b978dd5 |
1247 | =head1 COPYRIGHT AND LICENSE |
1248 | |
1249 | Copyright 2006 by Infinity Interactive, Inc. |
1250 | |
1251 | L<http://www.iinteractive.com> |
1252 | |
1253 | This library is free software; you can redistribute it and/or modify |
1254 | it under the same terms as Perl itself. |
1255 | |
798baea5 |
1256 | =cut |