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'; |
96ceced8 |
10 | use B 'svref_2object'; |
8b978dd5 |
11 | |
587aca23 |
12 | our $VERSION = '0.11'; |
8b978dd5 |
13 | |
aa448b16 |
14 | # Self-introspection |
2eb717d5 |
15 | |
aa448b16 |
16 | sub meta { Class::MOP::Class->initialize(blessed($_[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? |
587aca23 |
25 | my %METAS; |
26 | |
27 | # means of accessing all the metaclasses that have |
28 | # been initialized thus far (for mugwumps obj browser) |
29 | sub get_all_metaclasses { %METAS } |
30 | sub get_all_metaclass_instances { values %METAS } |
31 | sub get_all_metaclass_names { keys %METAS } |
651955fb |
32 | |
bfe4d0fc |
33 | sub initialize { |
351bd7d4 |
34 | my $class = shift; |
35 | my $package_name = shift; |
22286063 |
36 | (defined $package_name && $package_name && !blessed($package_name)) |
37 | || confess "You must pass a package name and it cannot be blessed"; |
651955fb |
38 | $class->construct_class_instance(':package' => $package_name, @_); |
727919c5 |
39 | } |
40 | |
41 | # NOTE: (meta-circularity) |
42 | # this is a special form of &construct_instance |
43 | # (see below), which is used to construct class |
1a7ebbb3 |
44 | # meta-object instances for any Class::MOP::* |
45 | # class. All other classes will use the more |
46 | # normal &construct_instance. |
727919c5 |
47 | sub construct_class_instance { |
351bd7d4 |
48 | my $class = shift; |
651955fb |
49 | my %options = @_; |
50 | my $package_name = $options{':package'}; |
727919c5 |
51 | (defined $package_name && $package_name) |
651955fb |
52 | || confess "You must pass a package name"; |
2f6d5412 |
53 | # NOTE: |
54 | # return the metaclass if we have it cached, |
55 | # and it is still defined (it has not been |
56 | # reaped by DESTROY yet, which can happen |
57 | # annoyingly enough during global destruction) |
58 | return $METAS{$package_name} |
59 | if exists $METAS{$package_name} && defined $METAS{$package_name}; |
1a7ebbb3 |
60 | $class = blessed($class) || $class; |
550d56db |
61 | # now create the metaclass |
62 | my $meta; |
1a7ebbb3 |
63 | if ($class =~ /^Class::MOP::/) { |
550d56db |
64 | $meta = bless { |
351bd7d4 |
65 | '$:package' => $package_name, |
66 | '%:attributes' => {}, |
550d56db |
67 | '$:attribute_metaclass' => $options{':attribute_metaclass'} || 'Class::MOP::Attribute', |
68 | '$:method_metaclass' => $options{':method_metaclass'} || 'Class::MOP::Method', |
1a7ebbb3 |
69 | } => $class; |
70 | } |
71 | else { |
5f3c057a |
72 | # NOTE: |
73 | # it is safe to use meta here because |
74 | # class will always be a subclass of |
75 | # Class::MOP::Class, which defines meta |
550d56db |
76 | $meta = bless $class->meta->construct_instance(%options) => $class |
1a7ebbb3 |
77 | } |
550d56db |
78 | # and check the metaclass compatibility |
79 | $meta->check_metaclass_compatability(); |
80 | $METAS{$package_name} = $meta; |
81 | } |
82 | |
83 | sub check_metaclass_compatability { |
84 | my $self = shift; |
85 | |
86 | # this is always okay ... |
87 | return if blessed($self) eq 'Class::MOP::Class'; |
88 | |
89 | my @class_list = $self->class_precedence_list; |
90 | shift @class_list; # shift off $self->name |
91 | |
92 | foreach my $class_name (@class_list) { |
96ceced8 |
93 | my $meta = $METAS{$class_name} || next; |
550d56db |
94 | ($self->isa(blessed($meta))) |
95 | || confess $self->name . "->meta => (" . (blessed($self)) . ")" . |
96 | " is not compatible with the " . |
97 | $class_name . "->meta => (" . (blessed($meta)) . ")"; |
98 | } |
bfe4d0fc |
99 | } |
8b978dd5 |
100 | } |
101 | |
102 | sub create { |
103 | my ($class, $package_name, $package_version, %options) = @_; |
bfe4d0fc |
104 | (defined $package_name && $package_name) |
8b978dd5 |
105 | || confess "You must pass a package name"; |
106 | my $code = "package $package_name;"; |
107 | $code .= "\$$package_name\:\:VERSION = '$package_version';" |
108 | if defined $package_version; |
109 | eval $code; |
110 | confess "creation of $package_name failed : $@" if $@; |
bfe4d0fc |
111 | my $meta = $class->initialize($package_name); |
aa448b16 |
112 | |
113 | $meta->add_method('meta' => sub { |
114 | Class::MOP::Class->initialize(blessed($_[0]) || $_[0]); |
115 | }); |
116 | |
8b978dd5 |
117 | $meta->superclasses(@{$options{superclasses}}) |
118 | if exists $options{superclasses}; |
2eb717d5 |
119 | # NOTE: |
120 | # process attributes first, so that they can |
121 | # install accessors, but locally defined methods |
122 | # can then overwrite them. It is maybe a little odd, but |
123 | # I think this should be the order of things. |
124 | if (exists $options{attributes}) { |
cbd9f942 |
125 | foreach my $attr (@{$options{attributes}}) { |
126 | $meta->add_attribute($attr); |
2eb717d5 |
127 | } |
128 | } |
bfe4d0fc |
129 | if (exists $options{methods}) { |
130 | foreach my $method_name (keys %{$options{methods}}) { |
131 | $meta->add_method($method_name, $options{methods}->{$method_name}); |
132 | } |
2eb717d5 |
133 | } |
8b978dd5 |
134 | return $meta; |
135 | } |
136 | |
c3e7c446 |
137 | { |
138 | my $ANON_CLASS_SERIAL = 0; |
139 | sub create_anon_class { |
140 | my ($class, %options) = @_; |
141 | my $package_name = 'Class::MOP::Class::__ANON__::SERIAL::' . ++$ANON_CLASS_SERIAL; |
142 | return $class->create($package_name, '0.00', %options); |
143 | } |
587aca23 |
144 | } |
145 | |
7b31baf4 |
146 | ## Attribute readers |
147 | |
148 | # NOTE: |
149 | # all these attribute readers will be bootstrapped |
150 | # away in the Class::MOP bootstrap section |
151 | |
152 | sub name { $_[0]->{'$:package'} } |
153 | sub get_attribute_map { $_[0]->{'%:attributes'} } |
154 | sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} } |
155 | sub method_metaclass { $_[0]->{'$:method_metaclass'} } |
156 | |
c9e77dbb |
157 | # Instance Construction & Cloning |
158 | |
5f3c057a |
159 | sub new_object { |
160 | my $class = shift; |
651955fb |
161 | # NOTE: |
162 | # we need to protect the integrity of the |
163 | # Class::MOP::Class singletons here, so we |
164 | # delegate this to &construct_class_instance |
165 | # which will deal with the singletons |
166 | return $class->construct_class_instance(@_) |
167 | if $class->name->isa('Class::MOP::Class'); |
5f3c057a |
168 | bless $class->construct_instance(@_) => $class->name; |
169 | } |
e16da3e6 |
170 | |
171 | sub construct_instance { |
cbd9f942 |
172 | my ($class, %params) = @_; |
173 | my $instance = {}; |
c9e77dbb |
174 | foreach my $attr ($class->compute_all_applicable_attributes()) { |
651955fb |
175 | my $init_arg = $attr->init_arg(); |
cbd9f942 |
176 | # try to fetch the init arg from the %params ... |
177 | my $val; |
178 | $val = $params{$init_arg} if exists $params{$init_arg}; |
179 | # if nothing was in the %params, we can use the |
180 | # attribute's default value (if it has one) |
a977cf65 |
181 | if (!defined $val && $attr->has_default) { |
182 | $val = $attr->default($instance); |
183 | } |
cbd9f942 |
184 | $instance->{$attr->name} = $val; |
185 | } |
186 | return $instance; |
e16da3e6 |
187 | } |
188 | |
5f3c057a |
189 | sub clone_object { |
190 | my $class = shift; |
7b31baf4 |
191 | my $instance = shift; |
651955fb |
192 | (blessed($instance) && $instance->isa($class->name)) |
193 | || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; |
194 | # NOTE: |
195 | # we need to protect the integrity of the |
196 | # Class::MOP::Class singletons here, they |
a740253a |
197 | # should not be cloned. |
651955fb |
198 | return $instance if $instance->isa('Class::MOP::Class'); |
199 | bless $class->clone_instance($instance, @_) => blessed($instance); |
5f3c057a |
200 | } |
201 | |
c9e77dbb |
202 | sub clone_instance { |
651955fb |
203 | my ($class, $instance, %params) = @_; |
204 | (blessed($instance)) |
c9e77dbb |
205 | || confess "You can only clone instances, \$self is not a blessed instance"; |
19d4b5b8 |
206 | my $clone = { %$instance, %params }; |
c9e77dbb |
207 | return $clone; |
208 | } |
209 | |
8b978dd5 |
210 | # Informational |
211 | |
7b31baf4 |
212 | # &name should be here too, but it is above |
213 | # because it gets bootstrapped away |
8b978dd5 |
214 | |
215 | sub version { |
216 | my $self = shift; |
96ceced8 |
217 | ${$self->get_package_variable('$VERSION')}; |
8b978dd5 |
218 | } |
219 | |
220 | # Inheritance |
221 | |
222 | sub superclasses { |
223 | my $self = shift; |
8b978dd5 |
224 | if (@_) { |
225 | my @supers = @_; |
96ceced8 |
226 | @{$self->get_package_variable('@ISA')} = @supers; |
8b978dd5 |
227 | } |
96ceced8 |
228 | @{$self->get_package_variable('@ISA')}; |
8b978dd5 |
229 | } |
230 | |
231 | sub class_precedence_list { |
232 | my $self = shift; |
bfe4d0fc |
233 | # NOTE: |
234 | # We need to check for ciruclar inheirtance here. |
235 | # This will do nothing if all is well, and blow |
236 | # up otherwise. Yes, it's an ugly hack, better |
237 | # suggestions are welcome. |
238 | { $self->name->isa('This is a test for circular inheritance') } |
8c936afc |
239 | # ... and now back to our regularly scheduled program |
8b978dd5 |
240 | ( |
241 | $self->name, |
242 | map { |
bfe4d0fc |
243 | $self->initialize($_)->class_precedence_list() |
8b978dd5 |
244 | } $self->superclasses() |
245 | ); |
246 | } |
247 | |
0882828e |
248 | ## Methods |
249 | |
250 | sub add_method { |
251 | my ($self, $method_name, $method) = @_; |
252 | (defined $method_name && $method_name) |
253 | || confess "You must define a method name"; |
a5eca695 |
254 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
255 | ('CODE' eq (reftype($method) || '')) |
0882828e |
256 | || confess "Your code block must be a CODE reference"; |
257 | my $full_method_name = ($self->name . '::' . $method_name); |
de19f115 |
258 | |
a4258ffd |
259 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
de19f115 |
260 | |
0882828e |
261 | no strict 'refs'; |
c9b8b7f9 |
262 | no warnings 'redefine'; |
22286063 |
263 | *{$full_method_name} = subname $full_method_name => $method; |
0882828e |
264 | } |
265 | |
a4258ffd |
266 | { |
267 | my $fetch_and_prepare_method = sub { |
268 | my ($self, $method_name) = @_; |
269 | # fetch it locally |
270 | my $method = $self->get_method($method_name); |
271 | # if we dont have local ... |
272 | unless ($method) { |
96ceced8 |
273 | # make sure this method even exists ... |
274 | ($self->find_next_method_by_name($method_name)) |
275 | || confess "The method '$method_name' is not found in the inherience hierarchy for this class"; |
276 | # if so, then create a local which just |
277 | # calls the next applicable method ... |
278 | $self->add_method($method_name => sub { |
279 | $self->find_next_method_by_name($method_name)->(@_); |
280 | }); |
a4258ffd |
281 | $method = $self->get_method($method_name); |
282 | } |
283 | |
284 | # now make sure we wrap it properly |
285 | # (if it isnt already) |
286 | unless ($method->isa('Class::MOP::Method::Wrapped')) { |
287 | $method = Class::MOP::Method::Wrapped->wrap($method); |
288 | $self->add_method($method_name => $method); |
289 | } |
290 | return $method; |
291 | }; |
292 | |
293 | sub add_before_method_modifier { |
294 | my ($self, $method_name, $method_modifier) = @_; |
295 | (defined $method_name && $method_name) |
8c936afc |
296 | || confess "You must pass in a method name"; |
a4258ffd |
297 | my $method = $fetch_and_prepare_method->($self, $method_name); |
8c936afc |
298 | $method->add_before_modifier(subname ':before' => $method_modifier); |
a4258ffd |
299 | } |
ddc8edba |
300 | |
a4258ffd |
301 | sub add_after_method_modifier { |
302 | my ($self, $method_name, $method_modifier) = @_; |
303 | (defined $method_name && $method_name) |
8c936afc |
304 | || confess "You must pass in a method name"; |
a4258ffd |
305 | my $method = $fetch_and_prepare_method->($self, $method_name); |
8c936afc |
306 | $method->add_after_modifier(subname ':after' => $method_modifier); |
ddc8edba |
307 | } |
308 | |
a4258ffd |
309 | sub add_around_method_modifier { |
310 | my ($self, $method_name, $method_modifier) = @_; |
311 | (defined $method_name && $method_name) |
312 | || confess "You must pass in a method name"; |
a4258ffd |
313 | my $method = $fetch_and_prepare_method->($self, $method_name); |
8c936afc |
314 | $method->add_around_modifier(subname ':around' => $method_modifier); |
a4258ffd |
315 | } |
316 | |
8c936afc |
317 | # NOTE: |
318 | # the methods above used to be named like this: |
319 | # ${pkg}::${method}:(before|after|around) |
320 | # but this proved problematic when using one modifier |
321 | # to wrap multiple methods (something which is likely |
322 | # to happen pretty regularly IMO). So instead of naming |
323 | # it like this, I have chosen to just name them purely |
324 | # with their modifier names, like so: |
325 | # :(before|after|around) |
326 | # The fact is that in a stack trace, it will be fairly |
327 | # evident from the context what method they are attached |
328 | # to, and so don't need the fully qualified name. |
ee5e71d4 |
329 | } |
330 | |
663f8198 |
331 | sub alias_method { |
332 | my ($self, $method_name, $method) = @_; |
333 | (defined $method_name && $method_name) |
334 | || confess "You must define a method name"; |
335 | # use reftype here to allow for blessed subs ... |
ee5e71d4 |
336 | ('CODE' eq (reftype($method) || '')) |
663f8198 |
337 | || confess "Your code block must be a CODE reference"; |
de19f115 |
338 | my $full_method_name = ($self->name . '::' . $method_name); |
339 | |
a4258ffd |
340 | $method = $self->method_metaclass->wrap($method) unless blessed($method); |
663f8198 |
341 | |
342 | no strict 'refs'; |
343 | no warnings 'redefine'; |
344 | *{$full_method_name} = $method; |
345 | } |
346 | |
de19f115 |
347 | sub has_method { |
348 | my ($self, $method_name) = @_; |
349 | (defined $method_name && $method_name) |
350 | || confess "You must define a method name"; |
bfe4d0fc |
351 | |
de19f115 |
352 | my $sub_name = ($self->name . '::' . $method_name); |
0882828e |
353 | |
de19f115 |
354 | no strict 'refs'; |
355 | return 0 if !defined(&{$sub_name}); |
de19f115 |
356 | my $method = \&{$sub_name}; |
96ceced8 |
357 | return 0 if (svref_2object($method)->GV->STASH->NAME || '') ne $self->name && |
358 | (svref_2object($method)->GV->NAME || '') ne '__ANON__'; |
de19f115 |
359 | |
96ceced8 |
360 | # at this point we are relatively sure |
361 | # it is our method, so we bless/wrap it |
362 | $self->method_metaclass->wrap($method) unless blessed($method); |
de19f115 |
363 | return 1; |
0882828e |
364 | } |
365 | |
366 | sub get_method { |
c9b8b7f9 |
367 | my ($self, $method_name) = @_; |
0882828e |
368 | (defined $method_name && $method_name) |
369 | || confess "You must define a method name"; |
370 | |
de19f115 |
371 | return unless $self->has_method($method_name); |
372 | |
0882828e |
373 | no strict 'refs'; |
de19f115 |
374 | return \&{$self->name . '::' . $method_name}; |
c9b8b7f9 |
375 | } |
376 | |
377 | sub remove_method { |
378 | my ($self, $method_name) = @_; |
379 | (defined $method_name && $method_name) |
380 | || confess "You must define a method name"; |
381 | |
382 | my $removed_method = $self->get_method($method_name); |
383 | |
384 | no strict 'refs'; |
385 | delete ${$self->name . '::'}{$method_name} |
386 | if defined $removed_method; |
387 | |
388 | return $removed_method; |
389 | } |
390 | |
391 | sub get_method_list { |
392 | my $self = shift; |
393 | no strict 'refs'; |
a5eca695 |
394 | grep { $self->has_method($_) } %{$self->name . '::'}; |
395 | } |
396 | |
397 | sub compute_all_applicable_methods { |
398 | my $self = shift; |
399 | my @methods; |
400 | # keep a record of what we have seen |
401 | # here, this will handle all the |
402 | # inheritence issues because we are |
403 | # using the &class_precedence_list |
404 | my (%seen_class, %seen_method); |
405 | foreach my $class ($self->class_precedence_list()) { |
406 | next if $seen_class{$class}; |
407 | $seen_class{$class}++; |
408 | # fetch the meta-class ... |
409 | my $meta = $self->initialize($class); |
410 | foreach my $method_name ($meta->get_method_list()) { |
411 | next if exists $seen_method{$method_name}; |
412 | $seen_method{$method_name}++; |
413 | push @methods => { |
414 | name => $method_name, |
415 | class => $class, |
416 | code => $meta->get_method($method_name) |
417 | }; |
418 | } |
419 | } |
420 | return @methods; |
421 | } |
422 | |
a5eca695 |
423 | sub find_all_methods_by_name { |
424 | my ($self, $method_name) = @_; |
425 | (defined $method_name && $method_name) |
426 | || confess "You must define a method name to find"; |
427 | my @methods; |
428 | # keep a record of what we have seen |
429 | # here, this will handle all the |
430 | # inheritence issues because we are |
431 | # using the &class_precedence_list |
432 | my %seen_class; |
433 | foreach my $class ($self->class_precedence_list()) { |
434 | next if $seen_class{$class}; |
435 | $seen_class{$class}++; |
436 | # fetch the meta-class ... |
96ceced8 |
437 | my $meta = $self->initialize($class); |
a5eca695 |
438 | push @methods => { |
439 | name => $method_name, |
440 | class => $class, |
441 | code => $meta->get_method($method_name) |
442 | } if $meta->has_method($method_name); |
443 | } |
444 | return @methods; |
8b978dd5 |
445 | } |
446 | |
96ceced8 |
447 | sub find_next_method_by_name { |
448 | my ($self, $method_name) = @_; |
449 | (defined $method_name && $method_name) |
450 | || confess "You must define a method name to find"; |
451 | # keep a record of what we have seen |
452 | # here, this will handle all the |
453 | # inheritence issues because we are |
454 | # using the &class_precedence_list |
455 | my %seen_class; |
456 | my @cpl = $self->class_precedence_list(); |
457 | shift @cpl; # discard ourselves |
458 | foreach my $class (@cpl) { |
459 | next if $seen_class{$class}; |
460 | $seen_class{$class}++; |
461 | # fetch the meta-class ... |
462 | my $meta = $self->initialize($class); |
463 | return $meta->get_method($method_name) |
464 | if $meta->has_method($method_name); |
465 | } |
466 | return; |
467 | } |
468 | |
552e3d24 |
469 | ## Attributes |
470 | |
e16da3e6 |
471 | sub add_attribute { |
2e41896e |
472 | my $self = shift; |
473 | # either we have an attribute object already |
474 | # or we need to create one from the args provided |
475 | my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); |
476 | # make sure it is derived from the correct type though |
477 | ($attribute->isa('Class::MOP::Attribute')) |
478 | || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; |
9ec169fe |
479 | $attribute->attach_to_class($self); |
480 | $attribute->install_accessors(); |
7b31baf4 |
481 | $self->get_attribute_map->{$attribute->name} = $attribute; |
e16da3e6 |
482 | } |
483 | |
484 | sub has_attribute { |
485 | my ($self, $attribute_name) = @_; |
486 | (defined $attribute_name && $attribute_name) |
487 | || confess "You must define an attribute name"; |
7b31baf4 |
488 | exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; |
e16da3e6 |
489 | } |
490 | |
491 | sub get_attribute { |
492 | my ($self, $attribute_name) = @_; |
493 | (defined $attribute_name && $attribute_name) |
494 | || confess "You must define an attribute name"; |
7b31baf4 |
495 | return $self->get_attribute_map->{$attribute_name} |
22286063 |
496 | if $self->has_attribute($attribute_name); |
497 | return; |
e16da3e6 |
498 | } |
499 | |
500 | sub remove_attribute { |
501 | my ($self, $attribute_name) = @_; |
502 | (defined $attribute_name && $attribute_name) |
503 | || confess "You must define an attribute name"; |
7b31baf4 |
504 | my $removed_attribute = $self->get_attribute_map->{$attribute_name}; |
22286063 |
505 | return unless defined $removed_attribute; |
506 | delete $self->get_attribute_map->{$attribute_name}; |
9ec169fe |
507 | $removed_attribute->remove_accessors(); |
508 | $removed_attribute->detach_from_class(); |
e16da3e6 |
509 | return $removed_attribute; |
510 | } |
511 | |
512 | sub get_attribute_list { |
513 | my $self = shift; |
7b31baf4 |
514 | keys %{$self->get_attribute_map}; |
e16da3e6 |
515 | } |
516 | |
517 | sub compute_all_applicable_attributes { |
518 | my $self = shift; |
519 | my @attrs; |
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, %seen_attr); |
525 | foreach my $class ($self->class_precedence_list()) { |
526 | next if $seen_class{$class}; |
527 | $seen_class{$class}++; |
528 | # fetch the meta-class ... |
529 | my $meta = $self->initialize($class); |
530 | foreach my $attr_name ($meta->get_attribute_list()) { |
531 | next if exists $seen_attr{$attr_name}; |
532 | $seen_attr{$attr_name}++; |
c9e77dbb |
533 | push @attrs => $meta->get_attribute($attr_name); |
e16da3e6 |
534 | } |
535 | } |
536 | return @attrs; |
537 | } |
2eb717d5 |
538 | |
52e8a34c |
539 | # Class attributes |
540 | |
541 | sub add_package_variable { |
542 | my ($self, $variable, $initial_value) = @_; |
543 | (defined $variable && $variable =~ /^[\$\@\%]/) |
544 | || confess "variable name does not have a sigil"; |
545 | |
546 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
547 | if (defined $initial_value) { |
548 | no strict 'refs'; |
549 | *{$self->name . '::' . $name} = $initial_value; |
550 | } |
551 | else { |
39ec4f0c |
552 | my $e; |
553 | { |
554 | # NOTE: |
555 | # We HAVE to localize $@ or all |
556 | # hell breaks loose. It is not |
557 | # good, believe me, not good. |
558 | local $@; |
559 | eval $sigil . $self->name . '::' . $name; |
560 | $e = $@ if $@; |
561 | } |
562 | confess "Could not create package variable ($variable) because : $e" if $e; |
52e8a34c |
563 | } |
564 | } |
565 | |
566 | sub has_package_variable { |
567 | my ($self, $variable) = @_; |
568 | (defined $variable && $variable =~ /^[\$\@\%]/) |
569 | || confess "variable name does not have a sigil"; |
570 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
571 | no strict 'refs'; |
572 | defined ${$self->name . '::'}{$name} ? 1 : 0; |
573 | } |
574 | |
575 | sub get_package_variable { |
576 | my ($self, $variable) = @_; |
577 | (defined $variable && $variable =~ /^[\$\@\%]/) |
578 | || confess "variable name does not have a sigil"; |
579 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
39ec4f0c |
580 | my ($ref, $e); |
581 | { |
582 | # NOTE: |
583 | # We HAVE to localize $@ or all |
584 | # hell breaks loose. It is not |
585 | # good, believe me, not good. |
586 | local $@; |
587 | $ref = eval '\\' . $sigil . $self->name . '::' . $name; |
588 | $e = $@ if $@; |
589 | } |
590 | confess "Could not get the package variable ($variable) because : $e" if $e; |
52e8a34c |
591 | # if we didn't die, then we can return it |
18697ac8 |
592 | return $ref; |
52e8a34c |
593 | } |
594 | |
595 | sub remove_package_variable { |
596 | my ($self, $variable) = @_; |
597 | (defined $variable && $variable =~ /^[\$\@\%]/) |
598 | || confess "variable name does not have a sigil"; |
599 | my ($sigil, $name) = ($variable =~ /^(.)(.*)$/); |
600 | no strict 'refs'; |
601 | delete ${$self->name . '::'}{$name}; |
602 | } |
603 | |
8b978dd5 |
604 | 1; |
605 | |
606 | __END__ |
607 | |
608 | =pod |
609 | |
610 | =head1 NAME |
611 | |
612 | Class::MOP::Class - Class Meta Object |
613 | |
614 | =head1 SYNOPSIS |
615 | |
8c936afc |
616 | # assuming that class Foo |
617 | # has been defined, you can |
618 | |
fe122940 |
619 | # use this for introspection ... |
620 | |
fe122940 |
621 | # add a method to Foo ... |
622 | Foo->meta->add_method('bar' => sub { ... }) |
623 | |
624 | # get a list of all the classes searched |
625 | # the method dispatcher in the correct order |
626 | Foo->meta->class_precedence_list() |
627 | |
628 | # remove a method from Foo |
629 | Foo->meta->remove_method('bar'); |
630 | |
631 | # or use this to actually create classes ... |
632 | |
633 | Class::MOP::Class->create('Bar' => '0.01' => ( |
634 | superclasses => [ 'Foo' ], |
635 | attributes => [ |
636 | Class::MOP:::Attribute->new('$bar'), |
637 | Class::MOP:::Attribute->new('$baz'), |
638 | ], |
639 | methods => { |
640 | calculate_bar => sub { ... }, |
641 | construct_baz => sub { ... } |
642 | } |
643 | )); |
644 | |
8b978dd5 |
645 | =head1 DESCRIPTION |
646 | |
fe122940 |
647 | This is the largest and currently most complex part of the Perl 5 |
648 | meta-object protocol. It controls the introspection and |
649 | manipulation of Perl 5 classes (and it can create them too). The |
650 | best way to understand what this module can do, is to read the |
651 | documentation for each of it's methods. |
652 | |
552e3d24 |
653 | =head1 METHODS |
654 | |
2eb717d5 |
655 | =head2 Self Introspection |
656 | |
657 | =over 4 |
658 | |
659 | =item B<meta> |
660 | |
fe122940 |
661 | This will return a B<Class::MOP::Class> instance which is related |
662 | to this class. Thereby allowing B<Class::MOP::Class> to actually |
663 | introspect itself. |
664 | |
665 | As with B<Class::MOP::Attribute>, B<Class::MOP> will actually |
666 | bootstrap this module by installing a number of attribute meta-objects |
667 | into it's metaclass. This will allow this class to reap all the benifits |
668 | of the MOP when subclassing it. |
2eb717d5 |
669 | |
587aca23 |
670 | =item B<get_all_metaclasses> |
671 | |
672 | This will return an hash of all the metaclass instances that have |
673 | been cached by B<Class::MOP::Class> keyed by the package name. |
674 | |
675 | =item B<get_all_metaclass_instances> |
676 | |
677 | This will return an array of all the metaclass instances that have |
678 | been cached by B<Class::MOP::Class>. |
679 | |
680 | =item B<get_all_metaclass_names> |
681 | |
682 | This will return an array of all the metaclass names that have |
683 | been cached by B<Class::MOP::Class>. |
684 | |
2eb717d5 |
685 | =back |
686 | |
552e3d24 |
687 | =head2 Class construction |
688 | |
a2e85e6c |
689 | These methods will handle creating B<Class::MOP::Class> objects, |
690 | which can be used to both create new classes, and analyze |
691 | pre-existing classes. |
552e3d24 |
692 | |
693 | This module will internally store references to all the instances |
694 | you create with these methods, so that they do not need to be |
695 | created any more than nessecary. Basically, they are singletons. |
696 | |
697 | =over 4 |
698 | |
699 | =item B<create ($package_name, ?$package_version, |
a2e85e6c |
700 | superclasses =E<gt> ?@superclasses, |
701 | methods =E<gt> ?%methods, |
702 | attributes =E<gt> ?%attributes)> |
552e3d24 |
703 | |
a2e85e6c |
704 | This returns a B<Class::MOP::Class> object, bringing the specified |
552e3d24 |
705 | C<$package_name> into existence and adding any of the |
706 | C<$package_version>, C<@superclasses>, C<%methods> and C<%attributes> |
707 | to it. |
708 | |
587aca23 |
709 | =item B<create_anon_class (superclasses =E<gt> ?@superclasses, |
710 | methods =E<gt> ?%methods, |
711 | attributes =E<gt> ?%attributes)> |
712 | |
713 | This will create an anonymous class, it works much like C<create> but |
714 | it does not need a C<$package_name>. Instead it will create a suitably |
715 | unique package name for you to stash things into. |
716 | |
552e3d24 |
717 | =item B<initialize ($package_name)> |
718 | |
a2e85e6c |
719 | This initializes and returns returns a B<Class::MOP::Class> object |
720 | for a given a C<$package_name>. |
721 | |
651955fb |
722 | =item B<construct_class_instance (%options)> |
a2e85e6c |
723 | |
724 | This will construct an instance of B<Class::MOP::Class>, it is |
725 | here so that we can actually "tie the knot" for B<Class::MOP::Class> |
726 | to use C<construct_instance> once all the bootstrapping is done. This |
727 | method is used internally by C<initialize> and should never be called |
728 | from outside of that method really. |
552e3d24 |
729 | |
550d56db |
730 | =item B<check_metaclass_compatability> |
731 | |
732 | This method is called as the very last thing in the |
733 | C<construct_class_instance> method. This will check that the |
734 | metaclass you are creating is compatible with the metaclasses of all |
735 | your ancestors. For more inforamtion about metaclass compatibility |
736 | see the C<About Metaclass compatibility> section in L<Class::MOP>. |
737 | |
552e3d24 |
738 | =back |
739 | |
c9e77dbb |
740 | =head2 Object instance construction and cloning |
a2e85e6c |
741 | |
c9e77dbb |
742 | These methods are B<entirely optional>, it is up to you whether you want |
743 | to use them or not. |
552e3d24 |
744 | |
745 | =over 4 |
746 | |
5f3c057a |
747 | =item B<new_object (%params)> |
748 | |
749 | This is a convience method for creating a new object of the class, and |
750 | blessing it into the appropriate package as well. Ideally your class |
751 | would call a C<new> this method like so: |
752 | |
753 | sub MyClass::new { |
754 | my ($class, %param) = @_; |
755 | $class->meta->new_object(%params); |
756 | } |
757 | |
758 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
759 | but that is considered bad style, so we do not do that. |
760 | |
cbd9f942 |
761 | =item B<construct_instance (%params)> |
552e3d24 |
762 | |
c9e77dbb |
763 | This method is used to construct an instace structure suitable for |
764 | C<bless>-ing into your package of choice. It works in conjunction |
765 | with the Attribute protocol to collect all applicable attributes. |
766 | |
cbd9f942 |
767 | This will construct and instance using a HASH ref as storage |
552e3d24 |
768 | (currently only HASH references are supported). This will collect all |
a2e85e6c |
769 | the applicable attributes and layout out the fields in the HASH ref, |
770 | it will then initialize them using either use the corresponding key |
771 | in C<%params> or any default value or initializer found in the |
772 | attribute meta-object. |
727919c5 |
773 | |
5f3c057a |
774 | =item B<clone_object ($instance, %params)> |
775 | |
776 | This is a convience method for cloning an object instance, then |
19d4b5b8 |
777 | blessing it into the appropriate package. This method will call |
778 | C<clone_instance>, which performs a shallow copy of the object, |
779 | see that methods documentation for more details. Ideally your |
780 | class would call a C<clone> this method like so: |
5f3c057a |
781 | |
782 | sub MyClass::clone { |
783 | my ($self, %param) = @_; |
784 | $self->meta->clone_object($self, %params); |
785 | } |
786 | |
787 | Of course the ideal place for this would actually be in C<UNIVERSAL::> |
788 | but that is considered bad style, so we do not do that. |
789 | |
c9e77dbb |
790 | =item B<clone_instance($instance, %params)> |
791 | |
792 | This method is a compliment of C<construct_instance> (which means if |
19d4b5b8 |
793 | you override C<construct_instance>, you need to override this one too), |
794 | and clones the instance shallowly. |
a27ae83f |
795 | |
796 | The cloned structure returned is (like with C<construct_instance>) an |
797 | unC<bless>ed HASH reference, it is your responsibility to then bless |
798 | this cloned structure into the right class (which C<clone_object> will |
799 | do for you). |
c9e77dbb |
800 | |
19d4b5b8 |
801 | As of 0.11, this method will clone the C<$instance> structure shallowly, |
802 | as opposed to the deep cloning implemented in prior versions. After much |
803 | thought, research and discussion, I have decided that anything but basic |
804 | shallow cloning is outside the scope of the meta-object protocol. I |
805 | think Yuval "nothingmuch" Kogman put it best when he said that cloning |
806 | is too I<context-specific> to be part of the MOP. |
807 | |
552e3d24 |
808 | =back |
809 | |
810 | =head2 Informational |
811 | |
812 | =over 4 |
813 | |
814 | =item B<name> |
815 | |
a2e85e6c |
816 | This is a read-only attribute which returns the package name for the |
817 | given B<Class::MOP::Class> instance. |
552e3d24 |
818 | |
819 | =item B<version> |
820 | |
821 | This is a read-only attribute which returns the C<$VERSION> of the |
a2e85e6c |
822 | package for the given B<Class::MOP::Class> instance. |
552e3d24 |
823 | |
824 | =back |
825 | |
826 | =head2 Inheritance Relationships |
827 | |
828 | =over 4 |
829 | |
830 | =item B<superclasses (?@superclasses)> |
831 | |
832 | This is a read-write attribute which represents the superclass |
a2e85e6c |
833 | relationships of the class the B<Class::MOP::Class> instance is |
834 | associated with. Basically, it can get and set the C<@ISA> for you. |
552e3d24 |
835 | |
343203ee |
836 | B<NOTE:> |
837 | Perl will occasionally perform some C<@ISA> and method caching, if |
838 | you decide to change your superclass relationship at runtime (which |
839 | is quite insane and very much not recommened), then you should be |
840 | aware of this and the fact that this module does not make any |
841 | attempt to address this issue. |
842 | |
552e3d24 |
843 | =item B<class_precedence_list> |
844 | |
a2e85e6c |
845 | This computes the a list of all the class's ancestors in the same order |
846 | in which method dispatch will be done. This is similair to |
847 | what B<Class::ISA::super_path> does, but we don't remove duplicate names. |
552e3d24 |
848 | |
849 | =back |
850 | |
851 | =head2 Methods |
852 | |
853 | =over 4 |
854 | |
2e41896e |
855 | =item B<method_metaclass> |
856 | |
552e3d24 |
857 | =item B<add_method ($method_name, $method)> |
858 | |
859 | This will take a C<$method_name> and CODE reference to that |
a2e85e6c |
860 | C<$method> and install it into the class's package. |
552e3d24 |
861 | |
a2e85e6c |
862 | B<NOTE>: |
863 | This does absolutely nothing special to C<$method> |
552e3d24 |
864 | other than use B<Sub::Name> to make sure it is tagged with the |
865 | correct name, and therefore show up correctly in stack traces and |
866 | such. |
867 | |
663f8198 |
868 | =item B<alias_method ($method_name, $method)> |
869 | |
870 | This will take a C<$method_name> and CODE reference to that |
871 | C<$method> and alias the method into the class's package. |
872 | |
873 | B<NOTE>: |
874 | Unlike C<add_method>, this will B<not> try to name the |
875 | C<$method> using B<Sub::Name>, it only aliases the method in |
876 | the class's package. |
877 | |
552e3d24 |
878 | =item B<has_method ($method_name)> |
879 | |
a2e85e6c |
880 | This just provides a simple way to check if the class implements |
552e3d24 |
881 | a specific C<$method_name>. It will I<not> however, attempt to check |
a2e85e6c |
882 | if the class inherits the method (use C<UNIVERSAL::can> for that). |
552e3d24 |
883 | |
884 | This will correctly handle functions defined outside of the package |
885 | that use a fully qualified name (C<sub Package::name { ... }>). |
886 | |
887 | This will correctly handle functions renamed with B<Sub::Name> and |
888 | installed using the symbol tables. However, if you are naming the |
889 | subroutine outside of the package scope, you must use the fully |
890 | qualified name, including the package name, for C<has_method> to |
891 | correctly identify it. |
892 | |
893 | This will attempt to correctly ignore functions imported from other |
894 | packages using B<Exporter>. It breaks down if the function imported |
895 | is an C<__ANON__> sub (such as with C<use constant>), which very well |
896 | may be a valid method being applied to the class. |
897 | |
898 | In short, this method cannot always be trusted to determine if the |
899 | C<$method_name> is actually a method. However, it will DWIM about |
a2e85e6c |
900 | 90% of the time, so it's a small trade off I think. |
552e3d24 |
901 | |
902 | =item B<get_method ($method_name)> |
903 | |
904 | This will return a CODE reference of the specified C<$method_name>, |
905 | or return undef if that method does not exist. |
906 | |
907 | =item B<remove_method ($method_name)> |
908 | |
a2e85e6c |
909 | This will attempt to remove a given C<$method_name> from the class. |
552e3d24 |
910 | It will return the CODE reference that it has removed, and will |
911 | attempt to use B<Sub::Name> to clear the methods associated name. |
912 | |
913 | =item B<get_method_list> |
914 | |
915 | This will return a list of method names for all I<locally> defined |
916 | methods. It does B<not> provide a list of all applicable methods, |
917 | including any inherited ones. If you want a list of all applicable |
918 | methods, use the C<compute_all_applicable_methods> method. |
919 | |
920 | =item B<compute_all_applicable_methods> |
921 | |
a2e85e6c |
922 | This will return a list of all the methods names this class will |
923 | respond to, taking into account inheritance. The list will be a list of |
552e3d24 |
924 | HASH references, each one containing the following information; method |
925 | name, the name of the class in which the method lives and a CODE |
926 | reference for the actual method. |
927 | |
928 | =item B<find_all_methods_by_name ($method_name)> |
929 | |
930 | This will traverse the inheritence hierarchy and locate all methods |
931 | with a given C<$method_name>. Similar to |
932 | C<compute_all_applicable_methods> it returns a list of HASH references |
933 | with the following information; method name (which will always be the |
934 | same as C<$method_name>), the name of the class in which the method |
935 | lives and a CODE reference for the actual method. |
936 | |
937 | The list of methods produced is a distinct list, meaning there are no |
938 | duplicates in it. This is especially useful for things like object |
939 | initialization and destruction where you only want the method called |
940 | once, and in the correct order. |
941 | |
96ceced8 |
942 | =item B<find_next_method_by_name ($method_name)> |
943 | |
944 | This will return the first method to match a given C<$method_name> in |
945 | the superclasses, this is basically equivalent to calling |
946 | C<SUPER::$method_name>, but it can be dispatched at runtime. |
947 | |
552e3d24 |
948 | =back |
949 | |
a4258ffd |
950 | =head2 Method Modifiers |
951 | |
96ceced8 |
952 | Method modifiers are a concept borrowed from CLOS, in which a method |
953 | can be wrapped with I<before>, I<after> and I<around> method modifiers |
954 | that will be called everytime the method is called. |
955 | |
956 | =head3 How method modifiers work? |
957 | |
958 | Method modifiers work by wrapping the original method and then replacing |
959 | it in the classes symbol table. The wrappers will handle calling all the |
960 | modifiers in the appropariate orders and preserving the calling context |
961 | for the original method. |
962 | |
963 | Each method modifier serves a particular purpose, which may not be |
964 | obvious to users of other method wrapping modules. To start with, the |
965 | return values of I<before> and I<after> modifiers are ignored. This is |
966 | because thier purpose is B<not> to filter the input and output of the |
967 | primary method (this is done with an I<around> modifier). This may seem |
968 | like an odd restriction to some, but doing this allows for simple code |
969 | to be added at the begining or end of a method call without jeapordizing |
970 | the normal functioning of the primary method or placing any extra |
971 | responsibility on the code of the modifier. Of course if you have more |
972 | complex needs, then use the I<around> modifier, which uses a variation |
973 | of continutation passing style to allow for a high degree of flexibility. |
974 | |
975 | Before and around modifiers are called in last-defined-first-called order, |
976 | while after modifiers are called in first-defined-first-called order. So |
977 | the call tree might looks something like this: |
978 | |
979 | before 2 |
980 | before 1 |
981 | around 2 |
982 | around 1 |
983 | primary |
984 | after 1 |
985 | after 2 |
986 | |
987 | To see examples of using method modifiers, see the following examples |
988 | included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>, |
989 | F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a |
990 | classic CLOS usage example in the test F<017_add_method_modifier.t>. |
991 | |
992 | =head3 What is the performance impact? |
993 | |
994 | Of course there is a performance cost associated with method modifiers, |
995 | but we have made every effort to make that cost be directly proportional |
996 | to the amount of modifier features you utilize. |
997 | |
998 | The wrapping method does it's best to B<only> do as much work as it |
999 | absolutely needs to. In order to do this we have moved some of the |
1000 | performance costs to set-up time, where they are easier to amortize. |
1001 | |
1002 | All this said, my benchmarks have indicated the following: |
1003 | |
1004 | simple wrapper with no modifiers 100% slower |
1005 | simple wrapper with simple before modifier 400% slower |
1006 | simple wrapper with simple after modifier 450% slower |
1007 | simple wrapper with simple around modifier 500-550% slower |
1008 | simple wrapper with all 3 modifiers 1100% slower |
1009 | |
1010 | These numbers may seem daunting, but you must remember, every feature |
1011 | comes with some cost. To put things in perspective, just doing a simple |
1012 | C<AUTOLOAD> which does nothing but extract the name of the method called |
1013 | and return it costs about 400% over a normal method call. |
1014 | |
a4258ffd |
1015 | =over 4 |
1016 | |
1017 | =item B<add_before_method_modifier ($method_name, $code)> |
1018 | |
96ceced8 |
1019 | This will wrap the method at C<$method_name> and the supplied C<$code> |
1020 | will be passed the C<@_> arguments, and called before the original |
1021 | method is called. As specified above, the return value of the I<before> |
1022 | method modifiers is ignored, and it's ability to modify C<@_> is |
1023 | fairly limited. If you need to do either of these things, use an |
1024 | C<around> method modifier. |
1025 | |
a4258ffd |
1026 | =item B<add_after_method_modifier ($method_name, $code)> |
1027 | |
96ceced8 |
1028 | This will wrap the method at C<$method_name> so that the original |
1029 | method will be called, it's return values stashed, and then the |
1030 | supplied C<$code> will be passed the C<@_> arguments, and called. |
1031 | As specified above, the return value of the I<after> method |
1032 | modifiers is ignored, and it cannot modify the return values of |
1033 | the original method. If you need to do either of these things, use an |
1034 | C<around> method modifier. |
1035 | |
a4258ffd |
1036 | =item B<add_around_method_modifier ($method_name, $code)> |
1037 | |
96ceced8 |
1038 | This will wrap the method at C<$method_name> so that C<$code> |
1039 | will be called and passed the original method as an extra argument |
1040 | at the begining of the C<@_> argument list. This is a variation of |
1041 | continuation passing style, where the function prepended to C<@_> |
1042 | can be considered a continuation. It is up to C<$code> if it calls |
1043 | the original method or not, there is no restriction on what the |
1044 | C<$code> can or cannot do. |
1045 | |
a4258ffd |
1046 | =back |
1047 | |
552e3d24 |
1048 | =head2 Attributes |
1049 | |
1050 | It should be noted that since there is no one consistent way to define |
1051 | the attributes of a class in Perl 5. These methods can only work with |
1052 | the information given, and can not easily discover information on |
a2e85e6c |
1053 | their own. See L<Class::MOP::Attribute> for more details. |
552e3d24 |
1054 | |
1055 | =over 4 |
1056 | |
2e41896e |
1057 | =item B<attribute_metaclass> |
1058 | |
7b31baf4 |
1059 | =item B<get_attribute_map> |
1060 | |
552e3d24 |
1061 | =item B<add_attribute ($attribute_name, $attribute_meta_object)> |
1062 | |
a2e85e6c |
1063 | This stores a C<$attribute_meta_object> in the B<Class::MOP::Class> |
1064 | instance associated with the given class, and associates it with |
1065 | the C<$attribute_name>. Unlike methods, attributes within the MOP |
1066 | are stored as meta-information only. They will be used later to |
1067 | construct instances from (see C<construct_instance> above). |
552e3d24 |
1068 | More details about the attribute meta-objects can be found in the |
a2e85e6c |
1069 | L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol> |
1070 | section. |
1071 | |
1072 | It should be noted that any accessor, reader/writer or predicate |
1073 | methods which the C<$attribute_meta_object> has will be installed |
1074 | into the class at this time. |
552e3d24 |
1075 | |
1076 | =item B<has_attribute ($attribute_name)> |
1077 | |
a2e85e6c |
1078 | Checks to see if this class has an attribute by the name of |
552e3d24 |
1079 | C<$attribute_name> and returns a boolean. |
1080 | |
1081 | =item B<get_attribute ($attribute_name)> |
1082 | |
1083 | Returns the attribute meta-object associated with C<$attribute_name>, |
1084 | if none is found, it will return undef. |
1085 | |
1086 | =item B<remove_attribute ($attribute_name)> |
1087 | |
1088 | This will remove the attribute meta-object stored at |
1089 | C<$attribute_name>, then return the removed attribute meta-object. |
1090 | |
a2e85e6c |
1091 | B<NOTE:> |
1092 | Removing an attribute will only affect future instances of |
552e3d24 |
1093 | the class, it will not make any attempt to remove the attribute from |
1094 | any existing instances of the class. |
1095 | |
a2e85e6c |
1096 | It should be noted that any accessor, reader/writer or predicate |
1097 | methods which the attribute meta-object stored at C<$attribute_name> |
1098 | has will be removed from the class at this time. This B<will> make |
1099 | these attributes somewhat inaccessable in previously created |
1100 | instances. But if you are crazy enough to do this at runtime, then |
1101 | you are crazy enough to deal with something like this :). |
1102 | |
552e3d24 |
1103 | =item B<get_attribute_list> |
1104 | |
1105 | This returns a list of attribute names which are defined in the local |
1106 | class. If you want a list of all applicable attributes for a class, |
1107 | use the C<compute_all_applicable_attributes> method. |
1108 | |
1109 | =item B<compute_all_applicable_attributes> |
1110 | |
c9e77dbb |
1111 | This will traverse the inheritance heirachy and return a list of all |
1112 | the applicable attributes for this class. It does not construct a |
1113 | HASH reference like C<compute_all_applicable_methods> because all |
1114 | that same information is discoverable through the attribute |
1115 | meta-object itself. |
552e3d24 |
1116 | |
1117 | =back |
1118 | |
52e8a34c |
1119 | =head2 Package Variables |
1120 | |
1121 | Since Perl's classes are built atop the Perl package system, it is |
1122 | fairly common to use package scoped variables for things like static |
1123 | class variables. The following methods are convience methods for |
1124 | the creation and inspection of package scoped variables. |
1125 | |
1126 | =over 4 |
1127 | |
1128 | =item B<add_package_variable ($variable_name, ?$initial_value)> |
1129 | |
1130 | Given a C<$variable_name>, which must contain a leading sigil, this |
1131 | method will create that variable within the package which houses the |
1132 | class. It also takes an optional C<$initial_value>, which must be a |
1133 | reference of the same type as the sigil of the C<$variable_name> |
1134 | implies. |
1135 | |
1136 | =item B<get_package_variable ($variable_name)> |
1137 | |
1138 | This will return a reference to the package variable in |
1139 | C<$variable_name>. |
1140 | |
1141 | =item B<has_package_variable ($variable_name)> |
1142 | |
1143 | Returns true (C<1>) if there is a package variable defined for |
1144 | C<$variable_name>, and false (C<0>) otherwise. |
1145 | |
1146 | =item B<remove_package_variable ($variable_name)> |
1147 | |
1148 | This will attempt to remove the package variable at C<$variable_name>. |
1149 | |
1150 | =back |
1151 | |
8b978dd5 |
1152 | =head1 AUTHOR |
1153 | |
a2e85e6c |
1154 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
8b978dd5 |
1155 | |
1156 | =head1 COPYRIGHT AND LICENSE |
1157 | |
1158 | Copyright 2006 by Infinity Interactive, Inc. |
1159 | |
1160 | L<http://www.iinteractive.com> |
1161 | |
1162 | This library is free software; you can redistribute it and/or modify |
1163 | it under the same terms as Perl itself. |
1164 | |
1165 | =cut |