Commit | Line | Data |
8b978dd5 |
1 | |
2 | package Class::MOP::Class; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Carp 'confess'; |
0882828e |
8 | use Scalar::Util 'blessed', 'reftype'; |
8b978dd5 |
9 | use Sub::Name 'subname'; |
ddc8edba |
10 | use SUPER (); |
8b978dd5 |
11 | |
d3cb0d4a |
12 | our $VERSION = '0.06'; |
8b978dd5 |
13 | |
aa448b16 |
14 | # Self-introspection |
2eb717d5 |
15 | |
aa448b16 |
16 | sub meta { Class::MOP::Class->initialize(blessed($_[0]) || $_[0]) } |
2eb717d5 |
17 | |
8b978dd5 |
18 | # Creation |
19 | |
bfe4d0fc |
20 | { |
21 | # Metaclasses are singletons, so we cache them here. |
22 | # there is no need to worry about destruction though |
23 | # because they should die only when the program dies. |
24 | # After all, do package definitions even get reaped? |
651955fb |
25 | my %METAS; |
26 | |
bfe4d0fc |
27 | sub initialize { |
351bd7d4 |
28 | my $class = shift; |
29 | my $package_name = shift; |
22286063 |
30 | (defined $package_name && $package_name && !blessed($package_name)) |
31 | || confess "You must pass a package name and it cannot be blessed"; |
651955fb |
32 | $class->construct_class_instance(':package' => $package_name, @_); |
727919c5 |
33 | } |
34 | |
35 | # NOTE: (meta-circularity) |
36 | # this is a special form of &construct_instance |
37 | # (see below), which is used to construct class |
1a7ebbb3 |
38 | # meta-object instances for any Class::MOP::* |
39 | # class. All other classes will use the more |
40 | # normal &construct_instance. |
727919c5 |
41 | sub construct_class_instance { |
351bd7d4 |
42 | my $class = shift; |
651955fb |
43 | my %options = @_; |
44 | my $package_name = $options{':package'}; |
727919c5 |
45 | (defined $package_name && $package_name) |
651955fb |
46 | || confess "You must pass a package name"; |
47 | return $METAS{$package_name} if exists $METAS{$package_name}; |
1a7ebbb3 |
48 | $class = blessed($class) || $class; |
550d56db |
49 | # now create the metaclass |
50 | my $meta; |
1a7ebbb3 |
51 | if ($class =~ /^Class::MOP::/) { |
550d56db |
52 | $meta = bless { |
351bd7d4 |
53 | '$:package' => $package_name, |
54 | '%:attributes' => {}, |
550d56db |
55 | '$:attribute_metaclass' => $options{':attribute_metaclass'} || 'Class::MOP::Attribute', |
56 | '$:method_metaclass' => $options{':method_metaclass'} || 'Class::MOP::Method', |
1a7ebbb3 |
57 | } => $class; |
58 | } |
59 | else { |
5f3c057a |
60 | # NOTE: |
61 | # it is safe to use meta here because |
62 | # class will always be a subclass of |
63 | # Class::MOP::Class, which defines meta |
550d56db |
64 | $meta = bless $class->meta->construct_instance(%options) => $class |
1a7ebbb3 |
65 | } |
550d56db |
66 | # and check the metaclass compatibility |
67 | $meta->check_metaclass_compatability(); |
68 | $METAS{$package_name} = $meta; |
69 | } |
70 | |
71 | sub check_metaclass_compatability { |
72 | my $self = shift; |
73 | |
74 | # this is always okay ... |
75 | return if blessed($self) eq 'Class::MOP::Class'; |
76 | |
77 | my @class_list = $self->class_precedence_list; |
78 | shift @class_list; # shift off $self->name |
79 | |
80 | foreach my $class_name (@class_list) { |
550d56db |
81 | my $meta = $METAS{$class_name}; |
82 | ($self->isa(blessed($meta))) |
83 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
84 | " is not compatible with the " . |
85 | $class_name . "->meta => (" . (blessed($meta)) . ")"; |
86 | } |
bfe4d0fc |
87 | } |
8b978dd5 |
88 | } |
89 | |
90 | sub create { |
91 | my ($class, $package_name, $package_version, %options) = @_; |
bfe4d0fc |
92 | (defined $package_name && $package_name) |
8b978dd5 |
93 | || confess "You must pass a package name"; |
94 | my $code = "package $package_name;"; |
95 | $code .= "\$$package_name\:\:VERSION = '$package_version';" |
96 | if defined $package_version; |
97 | eval $code; |
98 | confess "creation of $package_name failed : $@" if $@; |
bfe4d0fc |
99 | my $meta = $class->initialize($package_name); |
aa448b16 |
100 | |
101 | $meta->add_method('meta' => sub { |
102 | Class::MOP::Class->initialize(blessed($_[0]) || $_[0]); |
103 | }); |
104 | |
8b978dd5 |
105 | $meta->superclasses(@{$options{superclasses}}) |
106 | if exists $options{superclasses}; |
2eb717d5 |
107 | # NOTE: |
108 | # process attributes first, so that they can |
109 | # install accessors, but locally defined methods |
110 | # can then overwrite them. It is maybe a little odd, but |
111 | # I think this should be the order of things. |
112 | if (exists $options{attributes}) { |
cbd9f942 |
113 | foreach my $attr (@{$options{attributes}}) { |
114 | $meta->add_attribute($attr); |
2eb717d5 |
115 | } |
116 | } |
bfe4d0fc |
117 | if (exists $options{methods}) { |
118 | foreach my $method_name (keys %{$options{methods}}) { |
119 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
120 | } |
2eb717d5 |
121 | } |
8b978dd5 |
122 | return $meta; |
123 | } |
124 | |
7b31baf4 |
125 | ## Attribute readers |
126 | |
127 | # NOTE: |
128 | # all these attribute readers will be bootstrapped |
129 | # away in the Class::MOP bootstrap section |
130 | |
131 | sub name { $_[0]->{'$:package'} } |
132 | sub get_attribute_map { $_[0]->{'%:attributes'} } |
133 | sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} } |
134 | sub method_metaclass { $_[0]->{'$:method_metaclass'} } |
135 | |
c9e77dbb |
136 | # Instance Construction & Cloning |
137 | |
5f3c057a |
138 | sub new_object { |
139 | my $class = shift; |
651955fb |
140 | # NOTE: |
141 | # we need to protect the integrity of the |
142 | # Class::MOP::Class singletons here, so we |
143 | # delegate this to &construct_class_instance |
144 | # which will deal with the singletons |
145 | return $class->construct_class_instance(@_) |
146 | if $class->name->isa('Class::MOP::Class'); |
5f3c057a |
147 | bless $class->construct_instance(@_) => $class->name; |
148 | } |
e16da3e6 |
149 | |
150 | sub construct_instance { |
cbd9f942 |
151 | my ($class, %params) = @_; |
152 | my $instance = {}; |
c9e77dbb |
153 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
651955fb |
154 | my $init_arg = $attr->init_arg(); |
cbd9f942 |
155 | # try to fetch the init arg from the %params ... |
156 | my $val; |
157 | $val = $params{$init_arg} if exists $params{$init_arg}; |
158 | # if nothing was in the %params, we can use the |
159 | # attribute's default value (if it has one) |
c9e77dbb |
160 | $val ||= $attr->default($instance) if $attr->has_default(); |
cbd9f942 |
161 | $instance->{$attr->name} = $val; |
162 | } |
163 | return $instance; |
e16da3e6 |
164 | } |
165 | |
5f3c057a |
166 | sub clone_object { |
167 | my $class = shift; |
7b31baf4 |
168 | my $instance = shift; |
651955fb |
169 | (blessed($instance) && $instance->isa($class->name)) |
170 | || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; |
171 | # NOTE: |
172 | # we need to protect the integrity of the |
173 | # Class::MOP::Class singletons here, they |
a740253a |
174 | # should not be cloned. |
651955fb |
175 | return $instance if $instance->isa('Class::MOP::Class'); |
176 | bless $class->clone_instance($instance, @_) => blessed($instance); |
5f3c057a |
177 | } |
178 | |
c9e77dbb |
179 | sub clone_instance { |
651955fb |
180 | my ($class, $instance, %params) = @_; |
181 | (blessed($instance)) |
c9e77dbb |
182 | || confess "You can only clone instances, \$self is not a blessed instance"; |
19d4b5b8 |
183 | my $clone = { %$instance, %params }; |
c9e77dbb |
184 | return $clone; |
185 | } |
186 | |
8b978dd5 |
187 | # Informational |
188 | |
7b31baf4 |
189 | # &name should be here too, but it is above |
190 | # because it gets bootstrapped away |
8b978dd5 |
191 | |
192 | sub version { |
193 | my $self = shift; |
194 | no strict 'refs'; |
195 | ${$self->name . '::VERSION'}; |
196 | } |
197 | |
198 | # Inheritance |
199 | |
200 | sub superclasses { |
201 | my $self = shift; |
202 | no strict 'refs'; |
203 | if (@_) { |
204 | my @supers = @_; |
205 | @{$self->name . '::ISA'} = @supers; |
206 | } |
207 | @{$self->name . '::ISA'}; |
208 | } |
209 | |
210 | sub class_precedence_list { |
211 | my $self = shift; |
bfe4d0fc |
212 | # NOTE: |
213 | # We need to check for ciruclar inheirtance here. |
214 | # This will do nothing if all is well, and blow |
215 | # up otherwise. Yes, it's an ugly hack, better |
216 | # suggestions are welcome. |
217 | { $self->name->isa('This is a test for circular inheritance') } |
218 | # ... and no back to our regularly scheduled program |
8b978dd5 |
219 | ( |
220 | $self->name, |
221 | map { |
bfe4d0fc |
222 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
223 | } $self->superclasses() |
224 | ); |
225 | } |
226 | |
0882828e |
227 | ## Methods |
228 | |
229 | sub add_method { |
230 | my ($self, $method_name, $method) = @_; |
231 | (defined $method_name && $method_name) |
232 | || confess "You must define a method name"; |
a5eca695 |
233 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
234 | ('CODE' eq (reftype($method) || '')) |
0882828e |
235 | || confess "Your code block must be a CODE reference"; |
236 | my $full_method_name = ($self->name . '::' . $method_name); |
de19f115 |
237 | |
a4258ffd |
238 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
de19f115 |
239 | |
0882828e |
240 | no strict 'refs'; |
c9b8b7f9 |
241 | no warnings 'redefine'; |
22286063 |
242 | *{$full_method_name} = subname $full_method_name => $method; |
0882828e |
243 | } |
244 | |
a4258ffd |
245 | { |
246 | my $fetch_and_prepare_method = sub { |
247 | my ($self, $method_name) = @_; |
248 | # fetch it locally |
249 | my $method = $self->get_method($method_name); |
250 | # if we dont have local ... |
251 | unless ($method) { |
252 | # create a local which just calls the SUPER method ... |
253 | $self->add_method($method_name => sub { $_[0]->super($method_name)->(@_) }); |
254 | $method = $self->get_method($method_name); |
255 | } |
256 | |
257 | # now make sure we wrap it properly |
258 | # (if it isnt already) |
259 | unless ($method->isa('Class::MOP::Method::Wrapped')) { |
260 | $method = Class::MOP::Method::Wrapped->wrap($method); |
261 | $self->add_method($method_name => $method); |
262 | } |
263 | return $method; |
264 | }; |
265 | |
266 | sub add_before_method_modifier { |
267 | my ($self, $method_name, $method_modifier) = @_; |
268 | (defined $method_name && $method_name) |
269 | || confess "You must pass in a method name"; |
270 | my $full_method_modifier_name = ($self->name . '::' . $method_name . ':before'); |
271 | my $method = $fetch_and_prepare_method->($self, $method_name); |
272 | $method->add_before_modifier(subname $full_method_modifier_name => $method_modifier); |
273 | } |
ddc8edba |
274 | |
a4258ffd |
275 | sub add_after_method_modifier { |
276 | my ($self, $method_name, $method_modifier) = @_; |
277 | (defined $method_name && $method_name) |
278 | || confess "You must pass in a method name"; |
279 | my $full_method_modifier_name = ($self->name . '::' . $method_name . ':after'); |
280 | my $method = $fetch_and_prepare_method->($self, $method_name); |
281 | $method->add_after_modifier(subname $full_method_modifier_name => $method_modifier); |
ddc8edba |
282 | } |
283 | |
a4258ffd |
284 | sub add_around_method_modifier { |
285 | my ($self, $method_name, $method_modifier) = @_; |
286 | (defined $method_name && $method_name) |
287 | || confess "You must pass in a method name"; |
288 | my $full_method_modifier_name = ($self->name . '::' . $method_name . ':around'); |
289 | my $method = $fetch_and_prepare_method->($self, $method_name); |
290 | $method->add_around_modifier(subname $full_method_modifier_name => $method_modifier); |
291 | } |
292 | |
ee5e71d4 |
293 | } |
294 | |
663f8198 |
295 | sub alias_method { |
296 | my ($self, $method_name, $method) = @_; |
297 | (defined $method_name && $method_name) |
298 | || confess "You must define a method name"; |
299 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
300 | ('CODE' eq (reftype($method) || '')) |
663f8198 |
301 | || confess "Your code block must be a CODE reference"; |
de19f115 |
302 | my $full_method_name = ($self->name . '::' . $method_name); |
303 | |
a4258ffd |
304 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
663f8198 |
305 | |
306 | no strict 'refs'; |
307 | no warnings 'redefine'; |
308 | *{$full_method_name} = $method; |
309 | } |
310 | |
de19f115 |
311 | sub has_method { |
312 | my ($self, $method_name) = @_; |
313 | (defined $method_name && $method_name) |
314 | || confess "You must define a method name"; |
bfe4d0fc |
315 | |
de19f115 |
316 | my $sub_name = ($self->name . '::' . $method_name); |
0882828e |
317 | |
de19f115 |
318 | no strict 'refs'; |
319 | return 0 if !defined(&{$sub_name}); |
320 | |
321 | my $method = \&{$sub_name}; |
a4258ffd |
322 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
de19f115 |
323 | |
324 | return 0 if $method->package_name ne $self->name && |
325 | $method->name ne '__ANON__'; |
326 | return 1; |
0882828e |
327 | } |
328 | |
329 | sub get_method { |
c9b8b7f9 |
330 | my ($self, $method_name) = @_; |
0882828e |
331 | (defined $method_name && $method_name) |
332 | || confess "You must define a method name"; |
333 | |
de19f115 |
334 | return unless $self->has_method($method_name); |
335 | |
0882828e |
336 | no strict 'refs'; |
de19f115 |
337 | return \&{$self->name . '::' . $method_name}; |
c9b8b7f9 |
338 | } |
339 | |
340 | sub remove_method { |
341 | my ($self, $method_name) = @_; |
342 | (defined $method_name && $method_name) |
343 | || confess "You must define a method name"; |
344 | |
345 | my $removed_method = $self->get_method($method_name); |
346 | |
347 | no strict 'refs'; |
348 | delete ${$self->name . '::'}{$method_name} |
349 | if defined $removed_method; |
350 | |
351 | return $removed_method; |
352 | } |
353 | |
354 | sub get_method_list { |
355 | my $self = shift; |
356 | no strict 'refs'; |
a5eca695 |
357 | grep { $self->has_method($_) } %{$self->name . '::'}; |
358 | } |
359 | |
360 | sub compute_all_applicable_methods { |
361 | my $self = shift; |
362 | my @methods; |
363 | # keep a record of what we have seen |
364 | # here, this will handle all the |
365 | # inheritence issues because we are |
366 | # using the &class_precedence_list |
367 | my (%seen_class, %seen_method); |
368 | foreach my $class ($self->class_precedence_list()) { |
369 | next if $seen_class{$class}; |
370 | $seen_class{$class}++; |
371 | # fetch the meta-class ... |
372 | my $meta = $self->initialize($class); |
373 | foreach my $method_name ($meta->get_method_list()) { |
374 | next if exists $seen_method{$method_name}; |
375 | $seen_method{$method_name}++; |
376 | push @methods => { |
377 | name => $method_name, |
378 | class => $class, |
379 | code => $meta->get_method($method_name) |
380 | }; |
381 | } |
382 | } |
383 | return @methods; |
384 | } |
385 | |
a5eca695 |
386 | sub find_all_methods_by_name { |
387 | my ($self, $method_name) = @_; |
388 | (defined $method_name && $method_name) |
389 | || confess "You must define a method name to find"; |
390 | my @methods; |
391 | # keep a record of what we have seen |
392 | # here, this will handle all the |
393 | # inheritence issues because we are |
394 | # using the &class_precedence_list |
395 | my %seen_class; |
396 | foreach my $class ($self->class_precedence_list()) { |
397 | next if $seen_class{$class}; |
398 | $seen_class{$class}++; |
399 | # fetch the meta-class ... |
aa448b16 |
400 | my $meta = $self->initialize($class);; |
a5eca695 |
401 | push @methods => { |
402 | name => $method_name, |
403 | class => $class, |
404 | code => $meta->get_method($method_name) |
405 | } if $meta->has_method($method_name); |
406 | } |
407 | return @methods; |
8b978dd5 |
408 | } |
409 | |
552e3d24 |
410 | ## Attributes |
411 | |
e16da3e6 |
412 | sub add_attribute { |
2e41896e |
413 | my $self = shift; |
414 | # either we have an attribute object already |
415 | # or we need to create one from the args provided |
416 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
417 | # make sure it is derived from the correct type though |
418 | ($attribute->isa('Class::MOP::Attribute')) |
419 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
9ec169fe |
420 | $attribute->attach_to_class($self); |
421 | $attribute->install_accessors(); |
7b31baf4 |
422 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
423 | } |
424 | |
425 | sub has_attribute { |
426 | my ($self, $attribute_name) = @_; |
427 | (defined $attribute_name && $attribute_name) |
428 | || confess "You must define an attribute name"; |
7b31baf4 |
429 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
e16da3e6 |
430 | } |
431 | |
432 | sub get_attribute { |
433 | my ($self, $attribute_name) = @_; |
434 | (defined $attribute_name && $attribute_name) |
435 | || confess "You must define an attribute name"; |
7b31baf4 |
436 | return $self->get_attribute_map->{$attribute_name} |
22286063 |
437 | if $self->has_attribute($attribute_name); |
438 | return; |
e16da3e6 |
439 | } |
440 | |
441 | sub remove_attribute { |
442 | my ($self, $attribute_name) = @_; |
443 | (defined $attribute_name && $attribute_name) |
444 | || confess "You must define an attribute name"; |
7b31baf4 |
445 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
446 | return unless defined $removed_attribute; |
447 | delete $self->get_attribute_map->{$attribute_name}; |
9ec169fe |
448 | $removed_attribute->remove_accessors(); |
449 | $removed_attribute->detach_from_class(); |
e16da3e6 |
450 | return $removed_attribute; |
451 | } |
452 | |
453 | sub get_attribute_list { |
454 | my $self = shift; |
7b31baf4 |
455 | keys %{$self->get_attribute_map}; |
e16da3e6 |
456 | } |
457 | |
458 | sub compute_all_applicable_attributes { |
459 | my $self = shift; |
460 | my @attrs; |
461 | # keep a record of what we have seen |
462 | # here, this will handle all the |
463 | # inheritence issues because we are |
464 | # using the &class_precedence_list |
465 | my (%seen_class, %seen_attr); |
466 | foreach my $class ($self->class_precedence_list()) { |
467 | next if $seen_class{$class}; |
468 | $seen_class{$class}++; |
469 | # fetch the meta-class ... |
470 | my $meta = $self->initialize($class); |
471 | foreach my $attr_name ($meta->get_attribute_list()) { |
472 | next if exists $seen_attr{$attr_name}; |
473 | $seen_attr{$attr_name}++; |
c9e77dbb |
474 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
475 | } |
476 | } |
477 | return @attrs; |
478 | } |
2eb717d5 |
479 | |
52e8a34c |
480 | # Class attributes |
481 | |
482 | sub add_package_variable { |
483 | my ($self, $variable, $initial_value) = @_; |
484 | (defined $variable && $variable =~ /^[\$\@\%]/) |
485 | || confess "variable name does not have a sigil"; |
486 | |
487 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
488 | if (defined $initial_value) { |
489 | no strict 'refs'; |
490 | *{$self->name . '::' . $name} = $initial_value; |
491 | } |
492 | else { |
493 | eval $sigil . $self->name . '::' . $name; |
494 | confess "Could not create package variable ($variable) because : $@" if $@; |
495 | } |
496 | } |
497 | |
498 | sub has_package_variable { |
499 | my ($self, $variable) = @_; |
500 | (defined $variable && $variable =~ /^[\$\@\%]/) |
501 | || confess "variable name does not have a sigil"; |
502 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
503 | no strict 'refs'; |
504 | defined ${$self->name . '::'}{$name} ? 1 : 0; |
505 | } |
506 | |
507 | sub get_package_variable { |
508 | my ($self, $variable) = @_; |
509 | (defined $variable && $variable =~ /^[\$\@\%]/) |
510 | || confess "variable name does not have a sigil"; |
511 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
512 | no strict 'refs'; |
513 | # try to fetch it first,.. see what happens |
18697ac8 |
514 | my $ref = eval '\\' . $sigil . $self->name . '::' . $name; |
52e8a34c |
515 | confess "Could not get the package variable ($variable) because : $@" if $@; |
516 | # if we didn't die, then we can return it |
18697ac8 |
517 | return $ref; |
52e8a34c |
518 | } |
519 | |
520 | sub remove_package_variable { |
521 | my ($self, $variable) = @_; |
522 | (defined $variable && $variable =~ /^[\$\@\%]/) |
523 | || confess "variable name does not have a sigil"; |
524 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
525 | no strict 'refs'; |
526 | delete ${$self->name . '::'}{$name}; |
527 | } |
528 | |
8b978dd5 |
529 | 1; |
530 | |
531 | __END__ |
532 | |
533 | =pod |
534 | |
535 | =head1 NAME |
536 | |
537 | Class::MOP::Class - Class Meta Object |
538 | |
539 | =head1 SYNOPSIS |
540 | |
fe122940 |
541 | # use this for introspection ... |
542 | |
fe122940 |
543 | # add a method to Foo ... |
544 | Foo->meta->add_method('bar' => sub { ... }) |
545 | |
546 | # get a list of all the classes searched |
547 | # the method dispatcher in the correct order |
548 | Foo->meta->class_precedence_list() |
549 | |
550 | # remove a method from Foo |
551 | Foo->meta->remove_method('bar'); |
552 | |
553 | # or use this to actually create classes ... |
554 | |
555 | Class::MOP::Class->create('Bar' => '0.01' => ( |
556 | superclasses => [ 'Foo' ], |
557 | attributes => [ |
558 | Class::MOP:::Attribute->new('$bar'), |
559 | Class::MOP:::Attribute->new('$baz'), |
560 | ], |
561 | methods => { |
562 | calculate_bar => sub { ... }, |
563 | construct_baz => sub { ... } |
564 | } |
565 | )); |
566 | |
8b978dd5 |
567 | =head1 DESCRIPTION |
568 | |
fe122940 |
569 | This is the largest and currently most complex part of the Perl 5 |
570 | meta-object protocol. It controls the introspection and |
571 | manipulation of Perl 5 classes (and it can create them too). The |
572 | best way to understand what this module can do, is to read the |
573 | documentation for each of it's methods. |
574 | |
552e3d24 |
575 | =head1 METHODS |
576 | |
2eb717d5 |
577 | =head2 Self Introspection |
578 | |
579 | =over 4 |
580 | |
581 | =item B<meta> |
582 | |
fe122940 |
583 | This will return a B<Class::MOP::Class> instance which is related |
584 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
585 | introspect itself. |
586 | |
587 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
588 | bootstrap this module by installing a number of attribute meta-objects |
589 | into it's metaclass. This will allow this class to reap all the benifits |
590 | of the MOP when subclassing it. |
2eb717d5 |
591 | |
592 | =back |
593 | |
552e3d24 |
594 | =head2 Class construction |
595 | |
a2e85e6c |
596 | These methods will handle creating B<Class::MOP::Class> objects, |
597 | which can be used to both create new classes, and analyze |
598 | pre-existing classes. |
552e3d24 |
599 | |
600 | This module will internally store references to all the instances |
601 | you create with these methods, so that they do not need to be |
602 | created any more than nessecary. Basically, they are singletons. |
603 | |
604 | =over 4 |
605 | |
606 | =item B<create ($package_name, ?$package_version, |
a2e85e6c |
607 | superclasses =E<gt> ?@superclasses, |
608 | methods =E<gt> ?%methods, |
609 | attributes =E<gt> ?%attributes)> |
552e3d24 |
610 | |
a2e85e6c |
611 | This returns a B<Class::MOP::Class> object, bringing the specified |
552e3d24 |
612 | C<$package_name> into existence and adding any of the |
613 | C<$package_version>, C<@superclasses>, C<%methods> and C<%attributes> |
614 | to it. |
615 | |
616 | =item B<initialize ($package_name)> |
617 | |
a2e85e6c |
618 | This initializes and returns returns a B<Class::MOP::Class> object |
619 | for a given a C<$package_name>. |
620 | |
651955fb |
621 | =item B<construct_class_instance (%options)> |
a2e85e6c |
622 | |
623 | This will construct an instance of B<Class::MOP::Class>, it is |
624 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
625 | to use C<construct_instance> once all the bootstrapping is done. This |
626 | method is used internally by C<initialize> and should never be called |
627 | from outside of that method really. |
552e3d24 |
628 | |
550d56db |
629 | =item B<check_metaclass_compatability> |
630 | |
631 | This method is called as the very last thing in the |
632 | C<construct_class_instance> method. This will check that the |
633 | metaclass you are creating is compatible with the metaclasses of all |
634 | your ancestors. For more inforamtion about metaclass compatibility |
635 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
636 | |
552e3d24 |
637 | =back |
638 | |
c9e77dbb |
639 | =head2 Object instance construction and cloning |
a2e85e6c |
640 | |
c9e77dbb |
641 | These methods are B<entirely optional>, it is up to you whether you want |
642 | to use them or not. |
552e3d24 |
643 | |
644 | =over 4 |
645 | |
5f3c057a |
646 | =item B<new_object (%params)> |
647 | |
648 | This is a convience method for creating a new object of the class, and |
649 | blessing it into the appropriate package as well. Ideally your class |
650 | would call a C<new> this method like so: |
651 | |
652 | sub MyClass::new { |
653 | my ($class, %param) = @_; |
654 | $class->meta->new_object(%params); |
655 | } |
656 | |
657 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
658 | but that is considered bad style, so we do not do that. |
659 | |
cbd9f942 |
660 | =item B<construct_instance (%params)> |
552e3d24 |
661 | |
c9e77dbb |
662 | This method is used to construct an instace structure suitable for |
663 | C<bless>-ing into your package of choice. It works in conjunction |
664 | with the Attribute protocol to collect all applicable attributes. |
665 | |
cbd9f942 |
666 | This will construct and instance using a HASH ref as storage |
552e3d24 |
667 | (currently only HASH references are supported). This will collect all |
a2e85e6c |
668 | the applicable attributes and layout out the fields in the HASH ref, |
669 | it will then initialize them using either use the corresponding key |
670 | in C<%params> or any default value or initializer found in the |
671 | attribute meta-object. |
727919c5 |
672 | |
5f3c057a |
673 | =item B<clone_object ($instance, %params)> |
674 | |
675 | This is a convience method for cloning an object instance, then |
19d4b5b8 |
676 | blessing it into the appropriate package. This method will call |
677 | C<clone_instance>, which performs a shallow copy of the object, |
678 | see that methods documentation for more details. Ideally your |
679 | class would call a C<clone> this method like so: |
5f3c057a |
680 | |
681 | sub MyClass::clone { |
682 | my ($self, %param) = @_; |
683 | $self->meta->clone_object($self, %params); |
684 | } |
685 | |
686 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
687 | but that is considered bad style, so we do not do that. |
688 | |
c9e77dbb |
689 | =item B<clone_instance($instance, %params)> |
690 | |
691 | This method is a compliment of C<construct_instance> (which means if |
19d4b5b8 |
692 | you override C<construct_instance>, you need to override this one too), |
693 | and clones the instance shallowly. |
a27ae83f |
694 | |
695 | The cloned structure returned is (like with C<construct_instance>) an |
696 | unC<bless>ed HASH reference, it is your responsibility to then bless |
697 | this cloned structure into the right class (which C<clone_object> will |
698 | do for you). |
c9e77dbb |
699 | |
19d4b5b8 |
700 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
701 | as opposed to the deep cloning implemented in prior versions. After much |
702 | thought, research and discussion, I have decided that anything but basic |
703 | shallow cloning is outside the scope of the meta-object protocol. I |
704 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
705 | is too I<context-specific> to be part of the MOP. |
706 | |
552e3d24 |
707 | =back |
708 | |
709 | =head2 Informational |
710 | |
711 | =over 4 |
712 | |
713 | =item B<name> |
714 | |
a2e85e6c |
715 | This is a read-only attribute which returns the package name for the |
716 | given B<Class::MOP::Class> instance. |
552e3d24 |
717 | |
718 | =item B<version> |
719 | |
720 | This is a read-only attribute which returns the C<$VERSION> of the |
a2e85e6c |
721 | package for the given B<Class::MOP::Class> instance. |
552e3d24 |
722 | |
723 | =back |
724 | |
725 | =head2 Inheritance Relationships |
726 | |
727 | =over 4 |
728 | |
729 | =item B<superclasses (?@superclasses)> |
730 | |
731 | This is a read-write attribute which represents the superclass |
a2e85e6c |
732 | relationships of the class the B<Class::MOP::Class> instance is |
733 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
734 | |
343203ee |
735 | B<NOTE:> |
736 | Perl will occasionally perform some C<@ISA> and method caching, if |
737 | you decide to change your superclass relationship at runtime (which |
738 | is quite insane and very much not recommened), then you should be |
739 | aware of this and the fact that this module does not make any |
740 | attempt to address this issue. |
741 | |
552e3d24 |
742 | =item B<class_precedence_list> |
743 | |
a2e85e6c |
744 | This computes the a list of all the class's ancestors in the same order |
745 | in which method dispatch will be done. This is similair to |
746 | what B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
747 | |
748 | =back |
749 | |
750 | =head2 Methods |
751 | |
752 | =over 4 |
753 | |
2e41896e |
754 | =item B<method_metaclass> |
755 | |
552e3d24 |
756 | =item B<add_method ($method_name, $method)> |
757 | |
758 | This will take a C<$method_name> and CODE reference to that |
a2e85e6c |
759 | C<$method> and install it into the class's package. |
552e3d24 |
760 | |
a2e85e6c |
761 | B<NOTE>: |
762 | This does absolutely nothing special to C<$method> |
552e3d24 |
763 | other than use B<Sub::Name> to make sure it is tagged with the |
764 | correct name, and therefore show up correctly in stack traces and |
765 | such. |
766 | |
663f8198 |
767 | =item B<alias_method ($method_name, $method)> |
768 | |
769 | This will take a C<$method_name> and CODE reference to that |
770 | C<$method> and alias the method into the class's package. |
771 | |
772 | B<NOTE>: |
773 | Unlike C<add_method>, this will B<not> try to name the |
774 | C<$method> using B<Sub::Name>, it only aliases the method in |
775 | the class's package. |
776 | |
552e3d24 |
777 | =item B<has_method ($method_name)> |
778 | |
a2e85e6c |
779 | This just provides a simple way to check if the class implements |
552e3d24 |
780 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
781 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
782 | |
783 | This will correctly handle functions defined outside of the package |
784 | that use a fully qualified name (C<sub Package::name { ... }>). |
785 | |
786 | This will correctly handle functions renamed with B<Sub::Name> and |
787 | installed using the symbol tables. However, if you are naming the |
788 | subroutine outside of the package scope, you must use the fully |
789 | qualified name, including the package name, for C<has_method> to |
790 | correctly identify it. |
791 | |
792 | This will attempt to correctly ignore functions imported from other |
793 | packages using B<Exporter>. It breaks down if the function imported |
794 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
795 | may be a valid method being applied to the class. |
796 | |
797 | In short, this method cannot always be trusted to determine if the |
798 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
799 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
800 | |
801 | =item B<get_method ($method_name)> |
802 | |
803 | This will return a CODE reference of the specified C<$method_name>, |
804 | or return undef if that method does not exist. |
805 | |
806 | =item B<remove_method ($method_name)> |
807 | |
a2e85e6c |
808 | This will attempt to remove a given C<$method_name> from the class. |
552e3d24 |
809 | It will return the CODE reference that it has removed, and will |
810 | attempt to use B<Sub::Name> to clear the methods associated name. |
811 | |
812 | =item B<get_method_list> |
813 | |
814 | This will return a list of method names for all I<locally> defined |
815 | methods. It does B<not> provide a list of all applicable methods, |
816 | including any inherited ones. If you want a list of all applicable |
817 | methods, use the C<compute_all_applicable_methods> method. |
818 | |
819 | =item B<compute_all_applicable_methods> |
820 | |
a2e85e6c |
821 | This will return a list of all the methods names this class will |
822 | respond to, taking into account inheritance. The list will be a list of |
552e3d24 |
823 | HASH references, each one containing the following information; method |
824 | name, the name of the class in which the method lives and a CODE |
825 | reference for the actual method. |
826 | |
827 | =item B<find_all_methods_by_name ($method_name)> |
828 | |
829 | This will traverse the inheritence hierarchy and locate all methods |
830 | with a given C<$method_name>. Similar to |
831 | C<compute_all_applicable_methods> it returns a list of HASH references |
832 | with the following information; method name (which will always be the |
833 | same as C<$method_name>), the name of the class in which the method |
834 | lives and a CODE reference for the actual method. |
835 | |
836 | The list of methods produced is a distinct list, meaning there are no |
837 | duplicates in it. This is especially useful for things like object |
838 | initialization and destruction where you only want the method called |
839 | once, and in the correct order. |
840 | |
841 | =back |
842 | |
a4258ffd |
843 | =head2 Method Modifiers |
844 | |
845 | =over 4 |
846 | |
847 | =item B<add_before_method_modifier ($method_name, $code)> |
848 | |
849 | =item B<add_after_method_modifier ($method_name, $code)> |
850 | |
851 | =item B<add_around_method_modifier ($method_name, $code)> |
852 | |
853 | =back |
854 | |
552e3d24 |
855 | =head2 Attributes |
856 | |
857 | It should be noted that since there is no one consistent way to define |
858 | the attributes of a class in Perl 5. These methods can only work with |
859 | the information given, and can not easily discover information on |
a2e85e6c |
860 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
861 | |
862 | =over 4 |
863 | |
2e41896e |
864 | =item B<attribute_metaclass> |
865 | |
7b31baf4 |
866 | =item B<get_attribute_map> |
867 | |
552e3d24 |
868 | =item B<add_attribute ($attribute_name, $attribute_meta_object)> |
869 | |
a2e85e6c |
870 | This stores a C<$attribute_meta_object> in the B<Class::MOP::Class> |
871 | instance associated with the given class, and associates it with |
872 | the C<$attribute_name>. Unlike methods, attributes within the MOP |
873 | are stored as meta-information only. They will be used later to |
874 | construct instances from (see C<construct_instance> above). |
552e3d24 |
875 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
876 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
877 | section. |
878 | |
879 | It should be noted that any accessor, reader/writer or predicate |
880 | methods which the C<$attribute_meta_object> has will be installed |
881 | into the class at this time. |
552e3d24 |
882 | |
883 | =item B<has_attribute ($attribute_name)> |
884 | |
a2e85e6c |
885 | Checks to see if this class has an attribute by the name of |
552e3d24 |
886 | C<$attribute_name> and returns a boolean. |
887 | |
888 | =item B<get_attribute ($attribute_name)> |
889 | |
890 | Returns the attribute meta-object associated with C<$attribute_name>, |
891 | if none is found, it will return undef. |
892 | |
893 | =item B<remove_attribute ($attribute_name)> |
894 | |
895 | This will remove the attribute meta-object stored at |
896 | C<$attribute_name>, then return the removed attribute meta-object. |
897 | |
a2e85e6c |
898 | B<NOTE:> |
899 | Removing an attribute will only affect future instances of |
552e3d24 |
900 | the class, it will not make any attempt to remove the attribute from |
901 | any existing instances of the class. |
902 | |
a2e85e6c |
903 | It should be noted that any accessor, reader/writer or predicate |
904 | methods which the attribute meta-object stored at C<$attribute_name> |
905 | has will be removed from the class at this time. This B<will> make |
906 | these attributes somewhat inaccessable in previously created |
907 | instances. But if you are crazy enough to do this at runtime, then |
908 | you are crazy enough to deal with something like this :). |
909 | |
552e3d24 |
910 | =item B<get_attribute_list> |
911 | |
912 | This returns a list of attribute names which are defined in the local |
913 | class. If you want a list of all applicable attributes for a class, |
914 | use the C<compute_all_applicable_attributes> method. |
915 | |
916 | =item B<compute_all_applicable_attributes> |
917 | |
c9e77dbb |
918 | This will traverse the inheritance heirachy and return a list of all |
919 | the applicable attributes for this class. It does not construct a |
920 | HASH reference like C<compute_all_applicable_methods> because all |
921 | that same information is discoverable through the attribute |
922 | meta-object itself. |
552e3d24 |
923 | |
924 | =back |
925 | |
52e8a34c |
926 | =head2 Package Variables |
927 | |
928 | Since Perl's classes are built atop the Perl package system, it is |
929 | fairly common to use package scoped variables for things like static |
930 | class variables. The following methods are convience methods for |
931 | the creation and inspection of package scoped variables. |
932 | |
933 | =over 4 |
934 | |
935 | =item B<add_package_variable ($variable_name, ?$initial_value)> |
936 | |
937 | Given a C<$variable_name>, which must contain a leading sigil, this |
938 | method will create that variable within the package which houses the |
939 | class. It also takes an optional C<$initial_value>, which must be a |
940 | reference of the same type as the sigil of the C<$variable_name> |
941 | implies. |
942 | |
943 | =item B<get_package_variable ($variable_name)> |
944 | |
945 | This will return a reference to the package variable in |
946 | C<$variable_name>. |
947 | |
948 | =item B<has_package_variable ($variable_name)> |
949 | |
950 | Returns true (C<1>) if there is a package variable defined for |
951 | C<$variable_name>, and false (C<0>) otherwise. |
952 | |
953 | =item B<remove_package_variable ($variable_name)> |
954 | |
955 | This will attempt to remove the package variable at C<$variable_name>. |
956 | |
957 | =back |
958 | |
8b978dd5 |
959 | =head1 AUTHOR |
960 | |
a2e85e6c |
961 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
962 | |
963 | =head1 COPYRIGHT AND LICENSE |
964 | |
965 | Copyright 2006 by Infinity Interactive, Inc. |
966 | |
967 | L<http://www.iinteractive.com> |
968 | |
969 | This library is free software; you can redistribute it and/or modify |
970 | it under the same terms as Perl itself. |
971 | |
972 | =cut |