Commit | Line | Data |
94b19069 |
1 | |
2 | package Class::MOP; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
5a2932cf |
7 | use 5.008; |
8 | |
3cf322a0 |
9 | use MRO::Compat; |
10 | |
4c105333 |
11 | use Carp 'confess'; |
73dad89f |
12 | use Scalar::Util 'weaken', 'isweak', 'reftype', 'blessed'; |
4154c4d0 |
13 | use Data::OptList; |
a8344505 |
14 | use Try::Tiny; |
fc4f8f91 |
15 | |
9b871d79 |
16 | use Class::MOP::Mixin::AttributeCore; |
17 | use Class::MOP::Mixin::HasAttributes; |
18 | use Class::MOP::Mixin::HasMethods; |
0531f510 |
19 | use Class::MOP::Class; |
20 | use Class::MOP::Attribute; |
21 | use Class::MOP::Method; |
22 | |
b1f5f41d |
23 | BEGIN { |
c7e28c19 |
24 | *IS_RUNNING_ON_5_10 = ($] < 5.009_005) |
11b56828 |
25 | ? sub () { 0 } |
c7e28c19 |
26 | : sub () { 1 }; |
46b23b44 |
27 | |
3ecd1b25 |
28 | # this is either part of core or set up appropriately by MRO::Compat |
29 | *check_package_cache_flag = \&mro::get_pkg_gen; |
b1f5f41d |
30 | } |
e0e4674a |
31 | |
a9f48b4b |
32 | our $VERSION = '1.11'; |
8a7085c1 |
33 | our $XS_VERSION = $VERSION; |
d519662a |
34 | $VERSION = eval $VERSION; |
c7e28c19 |
35 | our $AUTHORITY = 'cpan:STEVAN'; |
9d655b6d |
36 | |
4bfa5ddb |
37 | require XSLoader; |
38 | XSLoader::load( __PACKAGE__, $XS_VERSION ); |
d7bda114 |
39 | |
be7677c7 |
40 | { |
41 | # Metaclasses are singletons, so we cache them here. |
42 | # there is no need to worry about destruction though |
43 | # because they should die only when the program dies. |
44 | # After all, do package definitions even get reaped? |
247d5b3c |
45 | # Anonymous classes manage their own destruction. |
1d68af04 |
46 | my %METAS; |
47 | |
1d68af04 |
48 | sub get_all_metaclasses { %METAS } |
49 | sub get_all_metaclass_instances { values %METAS } |
50 | sub get_all_metaclass_names { keys %METAS } |
be7677c7 |
51 | sub get_metaclass_by_name { $METAS{$_[0]} } |
1d68af04 |
52 | sub store_metaclass_by_name { $METAS{$_[0]} = $_[1] } |
53 | sub weaken_metaclass { weaken($METAS{$_[0]}) } |
73dad89f |
54 | sub metaclass_is_weak { isweak($METAS{$_[0]}) } |
be7677c7 |
55 | sub does_metaclass_exist { exists $METAS{$_[0]} && defined $METAS{$_[0]} } |
efc98200 |
56 | sub remove_metaclass_by_name { delete $METAS{$_[0]}; return } |
1d68af04 |
57 | |
86866fb5 |
58 | # This handles instances as well as class names |
59 | sub class_of { |
82999986 |
60 | return unless defined $_[0]; |
86866fb5 |
61 | my $class = blessed($_[0]) || $_[0]; |
62 | return $METAS{$class}; |
63 | } |
64 | |
be7677c7 |
65 | # NOTE: |
1d68af04 |
66 | # We only cache metaclasses, meaning instances of |
67 | # Class::MOP::Class. We do not cache instance of |
be7677c7 |
68 | # Class::MOP::Package or Class::MOP::Module. Mostly |
1d68af04 |
69 | # because I don't yet see a good reason to do so. |
be7677c7 |
70 | } |
71 | |
44da14be |
72 | sub _class_to_pmfile { |
73 | my $class = shift; |
74 | |
75 | my $file = $class . '.pm'; |
76 | $file =~ s{::}{/}g; |
77 | |
78 | return $file; |
79 | } |
80 | |
063ad0c5 |
81 | sub load_first_existing_class { |
4154c4d0 |
82 | my $classes = Data::OptList::mkopt(\@_) |
a02f24cb |
83 | or return; |
5a24cf8a |
84 | |
4154c4d0 |
85 | foreach my $class (@{ $classes }) { |
86 | my $name = $class->[0]; |
87 | unless ( _is_valid_class_name($name) ) { |
88 | my $display = defined($name) ? $name : 'undef'; |
5a24cf8a |
89 | confess "Invalid class name ($display)"; |
90 | } |
ab5e2f48 |
91 | } |
92 | |
063ad0c5 |
93 | my $found; |
5a24cf8a |
94 | my %exceptions; |
063ad0c5 |
95 | |
4154c4d0 |
96 | for my $class (@{ $classes }) { |
97 | my ($name, $options) = @{ $class }; |
5a24cf8a |
98 | |
4154c4d0 |
99 | if ($options) { |
100 | return $name if is_class_loaded($name, $options); |
101 | if (is_class_loaded($name)) { |
102 | # we already know it's loaded and too old, but we call |
103 | # ->VERSION anyway to generate the exception for us |
104 | $name->VERSION($options->{-version}); |
105 | } |
106 | } |
107 | else { |
108 | return $name if is_class_loaded($name); |
109 | } |
07940968 |
110 | |
4154c4d0 |
111 | my $file = _class_to_pmfile($name); |
112 | return $name if try { |
a02f24cb |
113 | local $SIG{__DIE__}; |
114 | require $file; |
4154c4d0 |
115 | $name->VERSION($options->{-version}) |
116 | if defined $options->{-version}; |
a02f24cb |
117 | return 1; |
118 | } |
119 | catch { |
120 | unless (/^Can't locate \Q$file\E in \@INC/) { |
4154c4d0 |
121 | confess "Couldn't load class ($name) because: $_"; |
44da14be |
122 | } |
063ad0c5 |
123 | |
a02f24cb |
124 | return; |
125 | }; |
a8344505 |
126 | } |
a8344505 |
127 | |
4154c4d0 |
128 | if ( @{ $classes } > 1 ) { |
129 | my @list = map { $_->[0] } @{ $classes }; |
130 | confess "Can't locate any of @list in \@INC (\@INC contains: @INC)."; |
a02f24cb |
131 | } else { |
4154c4d0 |
132 | confess "Can't locate " . _class_to_pmfile($classes->[0]->[0]) . " in \@INC (\@INC contains: @INC)."; |
a02f24cb |
133 | } |
063ad0c5 |
134 | } |
135 | |
5a24cf8a |
136 | sub load_class { |
4154c4d0 |
137 | load_first_existing_class($_[0], ref $_[1] ? $_[1] : ()); |
7716a8f9 |
138 | |
674d9359 |
139 | # This is done to avoid breaking code which checked the return value. Said |
140 | # code is dumb. The return value was _always_ true, since it dies on |
141 | # failure! |
142 | return 1; |
448b6e55 |
143 | } |
144 | |
2c0fb064 |
145 | sub _is_valid_class_name { |
146 | my $class = shift; |
147 | |
148 | return 0 if ref($class); |
149 | return 0 unless defined($class); |
150 | return 0 unless length($class); |
151 | |
152 | return 1 if $class =~ /^\w+(?:::\w+)*$/; |
153 | |
154 | return 0; |
155 | } |
156 | |
aa448b16 |
157 | ## ---------------------------------------------------------------------------- |
158 | ## Setting up our environment ... |
159 | ## ---------------------------------------------------------------------------- |
1d68af04 |
160 | ## Class::MOP needs to have a few things in the global perl environment so |
aa448b16 |
161 | ## that it can operate effectively. Those things are done here. |
162 | ## ---------------------------------------------------------------------------- |
163 | |
3bf7644b |
164 | # ... nothing yet actually ;) |
8b978dd5 |
165 | |
b51af7f9 |
166 | ## ---------------------------------------------------------------------------- |
1d68af04 |
167 | ## Bootstrapping |
b51af7f9 |
168 | ## ---------------------------------------------------------------------------- |
1d68af04 |
169 | ## The code below here is to bootstrap our MOP with itself. This is also |
b51af7f9 |
170 | ## sometimes called "tying the knot". By doing this, we make it much easier |
171 | ## to extend the MOP through subclassing and such since now you can use the |
1d68af04 |
172 | ## MOP itself to extend itself. |
173 | ## |
b51af7f9 |
174 | ## Yes, I know, thats weird and insane, but it's a good thing, trust me :) |
1d68af04 |
175 | ## ---------------------------------------------------------------------------- |
727919c5 |
176 | |
1d68af04 |
177 | # We need to add in the meta-attributes here so that |
178 | # any subclass of Class::MOP::* will be able to |
c2b256bc |
179 | # inherit them using _construct_instance |
727919c5 |
180 | |
f0480c45 |
181 | ## -------------------------------------------------------- |
9b871d79 |
182 | ## Class::MOP::Mixin::HasMethods |
727919c5 |
183 | |
9b871d79 |
184 | Class::MOP::Mixin::HasMethods->meta->add_attribute( |
185 | Class::MOP::Attribute->new('_methods' => ( |
b880e0de |
186 | reader => { |
9b871d79 |
187 | # NOTE: |
ce2ae40f |
188 | # we just alias the original method |
1d68af04 |
189 | # rather than re-produce it here |
38bcde3f |
190 | '_method_map' => \&Class::MOP::Mixin::HasMethods::_method_map |
b880e0de |
191 | }, |
9b871d79 |
192 | default => sub { {} } |
727919c5 |
193 | )) |
194 | ); |
195 | |
9b871d79 |
196 | Class::MOP::Mixin::HasMethods->meta->add_attribute( |
197 | Class::MOP::Attribute->new('method_metaclass' => ( |
198 | reader => { |
56dcfc1a |
199 | # NOTE: |
ce2ae40f |
200 | # we just alias the original method |
201 | # rather than re-produce it here |
9b871d79 |
202 | 'method_metaclass' => \&Class::MOP::Mixin::HasMethods::method_metaclass |
a5e51f0b |
203 | }, |
9b871d79 |
204 | default => 'Class::MOP::Method', |
a5e51f0b |
205 | )) |
206 | ); |
207 | |
9b871d79 |
208 | Class::MOP::Mixin::HasMethods->meta->add_attribute( |
209 | Class::MOP::Attribute->new('wrapped_method_metaclass' => ( |
bcef1f7c |
210 | reader => { |
211 | # NOTE: |
212 | # we just alias the original method |
213 | # rather than re-produce it here |
9b871d79 |
214 | 'wrapped_method_metaclass' => \&Class::MOP::Mixin::HasMethods::wrapped_method_metaclass |
bcef1f7c |
215 | }, |
9b871d79 |
216 | default => 'Class::MOP::Method::Wrapped', |
bcef1f7c |
217 | )) |
218 | ); |
219 | |
9b871d79 |
220 | ## -------------------------------------------------------- |
221 | ## Class::MOP::Mixin::HasMethods |
222 | |
223 | Class::MOP::Mixin::HasAttributes->meta->add_attribute( |
224 | Class::MOP::Attribute->new('attributes' => ( |
225 | reader => { |
226 | # NOTE: we need to do this in order |
227 | # for the instance meta-object to |
228 | # not fall into meta-circular death |
229 | # |
230 | # we just alias the original method |
231 | # rather than re-produce it here |
232 | '_attribute_map' => \&Class::MOP::Mixin::HasAttributes::_attribute_map |
233 | }, |
234 | default => sub { {} } |
235 | )) |
236 | ); |
237 | |
238 | Class::MOP::Mixin::HasAttributes->meta->add_attribute( |
239 | Class::MOP::Attribute->new('attribute_metaclass' => ( |
b1ff395f |
240 | reader => { |
241 | # NOTE: |
242 | # we just alias the original method |
243 | # rather than re-produce it here |
9b871d79 |
244 | 'attribute_metaclass' => \&Class::MOP::Mixin::HasAttributes::attribute_metaclass |
b1ff395f |
245 | }, |
9b871d79 |
246 | default => 'Class::MOP::Attribute', |
b1ff395f |
247 | )) |
248 | ); |
249 | |
9b871d79 |
250 | ## -------------------------------------------------------- |
251 | ## Class::MOP::Package |
252 | |
b1ff395f |
253 | Class::MOP::Package->meta->add_attribute( |
9b871d79 |
254 | Class::MOP::Attribute->new('package' => ( |
b1ff395f |
255 | reader => { |
9b871d79 |
256 | # NOTE: we need to do this in order |
257 | # for the instance meta-object to |
258 | # not fall into meta-circular death |
259 | # |
260 | # we just alias the original method |
261 | # rather than re-produce it here |
262 | 'name' => \&Class::MOP::Package::name |
263 | }, |
264 | )) |
265 | ); |
266 | |
267 | Class::MOP::Package->meta->add_attribute( |
268 | Class::MOP::Attribute->new('namespace' => ( |
269 | reader => { |
b1ff395f |
270 | # NOTE: |
271 | # we just alias the original method |
272 | # rather than re-produce it here |
9b871d79 |
273 | 'namespace' => \&Class::MOP::Package::namespace |
b1ff395f |
274 | }, |
9b871d79 |
275 | init_arg => undef, |
276 | default => sub { \undef } |
b1ff395f |
277 | )) |
278 | ); |
279 | |
f0480c45 |
280 | ## -------------------------------------------------------- |
281 | ## Class::MOP::Module |
282 | |
283 | # NOTE: |
1d68af04 |
284 | # yeah this is kind of stretching things a bit, |
f0480c45 |
285 | # but truthfully the version should be an attribute |
1d68af04 |
286 | # of the Module, the weirdness comes from having to |
287 | # stick to Perl 5 convention and store it in the |
288 | # $VERSION package variable. Basically if you just |
289 | # squint at it, it will look how you want it to look. |
f0480c45 |
290 | # Either as a package variable, or as a attribute of |
291 | # the metaclass, isn't abstraction great :) |
292 | |
293 | Class::MOP::Module->meta->add_attribute( |
8683db0e |
294 | Class::MOP::Attribute->new('version' => ( |
f0480c45 |
295 | reader => { |
ce2ae40f |
296 | # NOTE: |
297 | # we just alias the original method |
1d68af04 |
298 | # rather than re-produce it here |
ce2ae40f |
299 | 'version' => \&Class::MOP::Module::version |
f0480c45 |
300 | }, |
2e877f58 |
301 | init_arg => undef, |
c4260b45 |
302 | default => sub { \undef } |
f0480c45 |
303 | )) |
304 | ); |
305 | |
306 | # NOTE: |
1d68af04 |
307 | # By following the same conventions as version here, |
308 | # we are opening up the possibility that people can |
309 | # use the $AUTHORITY in non-Class::MOP modules as |
310 | # well. |
f0480c45 |
311 | |
312 | Class::MOP::Module->meta->add_attribute( |
8683db0e |
313 | Class::MOP::Attribute->new('authority' => ( |
f0480c45 |
314 | reader => { |
ce2ae40f |
315 | # NOTE: |
316 | # we just alias the original method |
1d68af04 |
317 | # rather than re-produce it here |
ce2ae40f |
318 | 'authority' => \&Class::MOP::Module::authority |
1d68af04 |
319 | }, |
2e877f58 |
320 | init_arg => undef, |
c4260b45 |
321 | default => sub { \undef } |
f0480c45 |
322 | )) |
323 | ); |
324 | |
325 | ## -------------------------------------------------------- |
6d5355c3 |
326 | ## Class::MOP::Class |
327 | |
727919c5 |
328 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
329 | Class::MOP::Attribute->new('superclasses' => ( |
c23184fc |
330 | accessor => { |
331 | # NOTE: |
332 | # we just alias the original method |
1d68af04 |
333 | # rather than re-produce it here |
c23184fc |
334 | 'superclasses' => \&Class::MOP::Class::superclasses |
335 | }, |
2e877f58 |
336 | init_arg => undef, |
c23184fc |
337 | default => sub { \undef } |
338 | )) |
339 | ); |
340 | |
341 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
342 | Class::MOP::Attribute->new('instance_metaclass' => ( |
b880e0de |
343 | reader => { |
1d68af04 |
344 | # NOTE: we need to do this in order |
345 | # for the instance meta-object to |
346 | # not fall into meta-circular death |
347 | # |
ce2ae40f |
348 | # we just alias the original method |
1d68af04 |
349 | # rather than re-produce it here |
ce2ae40f |
350 | 'instance_metaclass' => \&Class::MOP::Class::instance_metaclass |
b880e0de |
351 | }, |
1d68af04 |
352 | default => 'Class::MOP::Instance', |
2bab2be6 |
353 | )) |
354 | ); |
355 | |
44d6ea77 |
356 | Class::MOP::Class->meta->add_attribute( |
f5d08022 |
357 | Class::MOP::Attribute->new('immutable_trait' => ( |
358 | reader => { |
359 | 'immutable_trait' => \&Class::MOP::Class::immutable_trait |
360 | }, |
361 | default => "Class::MOP::Class::Immutable::Trait", |
362 | )) |
363 | ); |
364 | |
365 | Class::MOP::Class->meta->add_attribute( |
366 | Class::MOP::Attribute->new('constructor_name' => ( |
44d6ea77 |
367 | reader => { |
f5d08022 |
368 | 'constructor_name' => \&Class::MOP::Class::constructor_name, |
44d6ea77 |
369 | }, |
f5d08022 |
370 | default => "new", |
371 | )) |
372 | ); |
373 | |
374 | Class::MOP::Class->meta->add_attribute( |
375 | Class::MOP::Attribute->new('constructor_class' => ( |
44d6ea77 |
376 | reader => { |
f5d08022 |
377 | 'constructor_class' => \&Class::MOP::Class::constructor_class, |
44d6ea77 |
378 | }, |
f5d08022 |
379 | default => "Class::MOP::Method::Constructor", |
380 | )) |
381 | ); |
382 | |
383 | |
384 | Class::MOP::Class->meta->add_attribute( |
385 | Class::MOP::Attribute->new('destructor_class' => ( |
386 | reader => { |
387 | 'destructor_class' => \&Class::MOP::Class::destructor_class, |
44d6ea77 |
388 | }, |
389 | )) |
390 | ); |
391 | |
9d6dce77 |
392 | # NOTE: |
1d68af04 |
393 | # we don't actually need to tie the knot with |
394 | # Class::MOP::Class here, it is actually handled |
395 | # within Class::MOP::Class itself in the |
c2b256bc |
396 | # _construct_class_instance method. |
9d6dce77 |
397 | |
f0480c45 |
398 | ## -------------------------------------------------------- |
9b871d79 |
399 | ## Class::MOP::Mixin::AttributeCore |
400 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
401 | Class::MOP::Attribute->new('name' => ( |
c23184fc |
402 | reader => { |
1d68af04 |
403 | # NOTE: we need to do this in order |
404 | # for the instance meta-object to |
405 | # not fall into meta-circular death |
406 | # |
ce2ae40f |
407 | # we just alias the original method |
1d68af04 |
408 | # rather than re-produce it here |
9b871d79 |
409 | 'name' => \&Class::MOP::Mixin::AttributeCore::name |
b880e0de |
410 | } |
7b31baf4 |
411 | )) |
412 | ); |
413 | |
9b871d79 |
414 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
415 | Class::MOP::Attribute->new('accessor' => ( |
9b871d79 |
416 | reader => { 'accessor' => \&Class::MOP::Mixin::AttributeCore::accessor }, |
417 | predicate => { 'has_accessor' => \&Class::MOP::Mixin::AttributeCore::has_accessor }, |
7b31baf4 |
418 | )) |
419 | ); |
420 | |
9b871d79 |
421 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
422 | Class::MOP::Attribute->new('reader' => ( |
9b871d79 |
423 | reader => { 'reader' => \&Class::MOP::Mixin::AttributeCore::reader }, |
424 | predicate => { 'has_reader' => \&Class::MOP::Mixin::AttributeCore::has_reader }, |
7b31baf4 |
425 | )) |
426 | ); |
427 | |
9b871d79 |
428 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
429 | Class::MOP::Attribute->new('initializer' => ( |
9b871d79 |
430 | reader => { 'initializer' => \&Class::MOP::Mixin::AttributeCore::initializer }, |
431 | predicate => { 'has_initializer' => \&Class::MOP::Mixin::AttributeCore::has_initializer }, |
0ab65f99 |
432 | )) |
433 | ); |
434 | |
9b871d79 |
435 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
d9d99689 |
436 | Class::MOP::Attribute->new('definition_context' => ( |
9b871d79 |
437 | reader => { 'definition_context' => \&Class::MOP::Mixin::AttributeCore::definition_context }, |
d9d99689 |
438 | )) |
439 | ); |
440 | |
9b871d79 |
441 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
442 | Class::MOP::Attribute->new('writer' => ( |
9b871d79 |
443 | reader => { 'writer' => \&Class::MOP::Mixin::AttributeCore::writer }, |
444 | predicate => { 'has_writer' => \&Class::MOP::Mixin::AttributeCore::has_writer }, |
7b31baf4 |
445 | )) |
446 | ); |
447 | |
9b871d79 |
448 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
449 | Class::MOP::Attribute->new('predicate' => ( |
9b871d79 |
450 | reader => { 'predicate' => \&Class::MOP::Mixin::AttributeCore::predicate }, |
451 | predicate => { 'has_predicate' => \&Class::MOP::Mixin::AttributeCore::has_predicate }, |
7b31baf4 |
452 | )) |
453 | ); |
454 | |
9b871d79 |
455 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
456 | Class::MOP::Attribute->new('clearer' => ( |
9b871d79 |
457 | reader => { 'clearer' => \&Class::MOP::Mixin::AttributeCore::clearer }, |
458 | predicate => { 'has_clearer' => \&Class::MOP::Mixin::AttributeCore::has_clearer }, |
7d28758b |
459 | )) |
460 | ); |
461 | |
9b871d79 |
462 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
463 | Class::MOP::Attribute->new('builder' => ( |
9b871d79 |
464 | reader => { 'builder' => \&Class::MOP::Mixin::AttributeCore::builder }, |
465 | predicate => { 'has_builder' => \&Class::MOP::Mixin::AttributeCore::has_builder }, |
1d68af04 |
466 | )) |
467 | ); |
468 | |
9b871d79 |
469 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
470 | Class::MOP::Attribute->new('init_arg' => ( |
9b871d79 |
471 | reader => { 'init_arg' => \&Class::MOP::Mixin::AttributeCore::init_arg }, |
472 | predicate => { 'has_init_arg' => \&Class::MOP::Mixin::AttributeCore::has_init_arg }, |
7b31baf4 |
473 | )) |
474 | ); |
475 | |
9b871d79 |
476 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
8683db0e |
477 | Class::MOP::Attribute->new('default' => ( |
7b31baf4 |
478 | # default has a custom 'reader' method ... |
9b871d79 |
479 | predicate => { 'has_default' => \&Class::MOP::Mixin::AttributeCore::has_default }, |
7b31baf4 |
480 | )) |
481 | ); |
482 | |
9b871d79 |
483 | Class::MOP::Mixin::AttributeCore->meta->add_attribute( |
484 | Class::MOP::Attribute->new('insertion_order' => ( |
485 | reader => { 'insertion_order' => \&Class::MOP::Mixin::AttributeCore::insertion_order }, |
486 | writer => { '_set_insertion_order' => \&Class::MOP::Mixin::AttributeCore::_set_insertion_order }, |
487 | predicate => { 'has_insertion_order' => \&Class::MOP::Mixin::AttributeCore::has_insertion_order }, |
488 | )) |
489 | ); |
490 | |
491 | ## -------------------------------------------------------- |
492 | ## Class::MOP::Attribute |
3545c727 |
493 | Class::MOP::Attribute->meta->add_attribute( |
9b871d79 |
494 | Class::MOP::Attribute->new('associated_class' => ( |
495 | reader => { |
496 | # NOTE: we need to do this in order |
497 | # for the instance meta-object to |
498 | # not fall into meta-circular death |
499 | # |
500 | # we just alias the original method |
501 | # rather than re-produce it here |
502 | 'associated_class' => \&Class::MOP::Attribute::associated_class |
503 | } |
3545c727 |
504 | )) |
505 | ); |
727919c5 |
506 | |
95b67145 |
507 | Class::MOP::Attribute->meta->add_attribute( |
9b871d79 |
508 | Class::MOP::Attribute->new('associated_methods' => ( |
509 | reader => { 'associated_methods' => \&Class::MOP::Attribute::associated_methods }, |
510 | default => sub { [] } |
95b67145 |
511 | )) |
512 | ); |
513 | |
5659d76e |
514 | Class::MOP::Attribute->meta->add_method('clone' => sub { |
a740253a |
515 | my $self = shift; |
1d68af04 |
516 | $self->meta->clone_object($self, @_); |
727919c5 |
517 | }); |
518 | |
f0480c45 |
519 | ## -------------------------------------------------------- |
b6164407 |
520 | ## Class::MOP::Method |
b6164407 |
521 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
522 | Class::MOP::Attribute->new('body' => ( |
c23184fc |
523 | reader => { 'body' => \&Class::MOP::Method::body }, |
b6164407 |
524 | )) |
525 | ); |
526 | |
4c105333 |
527 | Class::MOP::Method->meta->add_attribute( |
5e607260 |
528 | Class::MOP::Attribute->new('associated_metaclass' => ( |
5e607260 |
529 | reader => { 'associated_metaclass' => \&Class::MOP::Method::associated_metaclass }, |
530 | )) |
531 | ); |
532 | |
533 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
534 | Class::MOP::Attribute->new('package_name' => ( |
4c105333 |
535 | reader => { 'package_name' => \&Class::MOP::Method::package_name }, |
536 | )) |
537 | ); |
538 | |
539 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
540 | Class::MOP::Attribute->new('name' => ( |
4c105333 |
541 | reader => { 'name' => \&Class::MOP::Method::name }, |
542 | )) |
543 | ); |
544 | |
2226a8b0 |
545 | Class::MOP::Method->meta->add_attribute( |
546 | Class::MOP::Attribute->new('original_method' => ( |
547 | reader => { 'original_method' => \&Class::MOP::Method::original_method }, |
548 | writer => { '_set_original_method' => \&Class::MOP::Method::_set_original_method }, |
549 | )) |
550 | ); |
551 | |
b6164407 |
552 | ## -------------------------------------------------------- |
553 | ## Class::MOP::Method::Wrapped |
554 | |
555 | # NOTE: |
1d68af04 |
556 | # the way this item is initialized, this |
557 | # really does not follow the standard |
558 | # practices of attributes, but we put |
b6164407 |
559 | # it here for completeness |
560 | Class::MOP::Method::Wrapped->meta->add_attribute( |
8683db0e |
561 | Class::MOP::Attribute->new('modifier_table') |
b6164407 |
562 | ); |
563 | |
564 | ## -------------------------------------------------------- |
565f0cbb |
565 | ## Class::MOP::Method::Generated |
566 | |
567 | Class::MOP::Method::Generated->meta->add_attribute( |
8683db0e |
568 | Class::MOP::Attribute->new('is_inline' => ( |
565f0cbb |
569 | reader => { 'is_inline' => \&Class::MOP::Method::Generated::is_inline }, |
4c105333 |
570 | default => 0, |
1d68af04 |
571 | )) |
565f0cbb |
572 | ); |
573 | |
d9d99689 |
574 | Class::MOP::Method::Generated->meta->add_attribute( |
575 | Class::MOP::Attribute->new('definition_context' => ( |
576 | reader => { 'definition_context' => \&Class::MOP::Method::Generated::definition_context }, |
577 | )) |
578 | ); |
579 | |
29d4e92a |
580 | |
581 | ## -------------------------------------------------------- |
582 | ## Class::MOP::Method::Inlined |
583 | |
584 | Class::MOP::Method::Inlined->meta->add_attribute( |
585 | Class::MOP::Attribute->new('_expected_method_class' => ( |
586 | reader => { '_expected_method_class' => \&Class::MOP::Method::Inlined::_expected_method_class }, |
587 | )) |
588 | ); |
589 | |
565f0cbb |
590 | ## -------------------------------------------------------- |
d90b42a6 |
591 | ## Class::MOP::Method::Accessor |
592 | |
593 | Class::MOP::Method::Accessor->meta->add_attribute( |
8683db0e |
594 | Class::MOP::Attribute->new('attribute' => ( |
1d68af04 |
595 | reader => { |
596 | 'associated_attribute' => \&Class::MOP::Method::Accessor::associated_attribute |
d90b42a6 |
597 | }, |
1d68af04 |
598 | )) |
d90b42a6 |
599 | ); |
600 | |
601 | Class::MOP::Method::Accessor->meta->add_attribute( |
8683db0e |
602 | Class::MOP::Attribute->new('accessor_type' => ( |
c23184fc |
603 | reader => { 'accessor_type' => \&Class::MOP::Method::Accessor::accessor_type }, |
1d68af04 |
604 | )) |
d90b42a6 |
605 | ); |
606 | |
d90b42a6 |
607 | ## -------------------------------------------------------- |
608 | ## Class::MOP::Method::Constructor |
609 | |
610 | Class::MOP::Method::Constructor->meta->add_attribute( |
8683db0e |
611 | Class::MOP::Attribute->new('options' => ( |
1d68af04 |
612 | reader => { |
613 | 'options' => \&Class::MOP::Method::Constructor::options |
d90b42a6 |
614 | }, |
4c105333 |
615 | default => sub { +{} } |
1d68af04 |
616 | )) |
d90b42a6 |
617 | ); |
618 | |
619 | Class::MOP::Method::Constructor->meta->add_attribute( |
8683db0e |
620 | Class::MOP::Attribute->new('associated_metaclass' => ( |
e8a38403 |
621 | init_arg => "metaclass", # FIXME alias and rename |
1d68af04 |
622 | reader => { |
623 | 'associated_metaclass' => \&Class::MOP::Method::Constructor::associated_metaclass |
624 | }, |
625 | )) |
d90b42a6 |
626 | ); |
627 | |
628 | ## -------------------------------------------------------- |
86482605 |
629 | ## Class::MOP::Instance |
630 | |
631 | # NOTE: |
1d68af04 |
632 | # these don't yet do much of anything, but are just |
86482605 |
633 | # included for completeness |
634 | |
635 | Class::MOP::Instance->meta->add_attribute( |
74890687 |
636 | Class::MOP::Attribute->new('associated_metaclass', |
637 | reader => { associated_metaclass => \&Class::MOP::Instance::associated_metaclass }, |
638 | ), |
86482605 |
639 | ); |
640 | |
641 | Class::MOP::Instance->meta->add_attribute( |
74890687 |
642 | Class::MOP::Attribute->new('_class_name', |
643 | init_arg => undef, |
644 | reader => { _class_name => \&Class::MOP::Instance::_class_name }, |
645 | #lazy => 1, # not yet supported by Class::MOP but out our version does it anyway |
646 | #default => sub { $_[0]->associated_metaclass->name }, |
647 | ), |
648 | ); |
649 | |
650 | Class::MOP::Instance->meta->add_attribute( |
651 | Class::MOP::Attribute->new('attributes', |
0b5d46da |
652 | reader => { attributes => \&Class::MOP::Instance::get_all_attributes }, |
74890687 |
653 | ), |
32bfc810 |
654 | ); |
655 | |
656 | Class::MOP::Instance->meta->add_attribute( |
74890687 |
657 | Class::MOP::Attribute->new('slots', |
658 | reader => { slots => \&Class::MOP::Instance::slots }, |
659 | ), |
86482605 |
660 | ); |
661 | |
63d08a9e |
662 | Class::MOP::Instance->meta->add_attribute( |
74890687 |
663 | Class::MOP::Attribute->new('slot_hash', |
664 | reader => { slot_hash => \&Class::MOP::Instance::slot_hash }, |
665 | ), |
63d08a9e |
666 | ); |
667 | |
28a82dda |
668 | ## -------------------------------------------------------- |
669 | ## Class::MOP::Object |
670 | |
671 | # need to replace the meta method there with a real meta method object |
37a46507 |
672 | Class::MOP::Object->meta->_add_meta_method('meta'); |
28a82dda |
673 | |
23ab51e4 |
674 | ## -------------------------------------------------------- |
675 | ## Class::MOP::Mixin |
676 | |
677 | # need to replace the meta method there with a real meta method object |
37a46507 |
678 | Class::MOP::Mixin->meta->_add_meta_method('meta'); |
23ab51e4 |
679 | |
30229767 |
680 | require Class::MOP::Deprecated unless our $no_deprecated; |
63d08a9e |
681 | |
caa051fa |
682 | # we need the meta instance of the meta instance to be created now, in order |
683 | # for the constructor to be able to use it |
684 | Class::MOP::Instance->meta->get_meta_instance; |
685 | |
caa051fa |
686 | # pretend the add_method never happenned. it hasn't yet affected anything |
687 | undef Class::MOP::Instance->meta->{_package_cache_flag}; |
688 | |
86482605 |
689 | ## -------------------------------------------------------- |
f0480c45 |
690 | ## Now close all the Class::MOP::* classes |
4d47b77f |
691 | |
1aa13cf4 |
692 | # NOTE: we don't need to inline the the accessors this only lengthens |
693 | # the compile time of the MOP, and gives us no actual benefits. |
0b9372a2 |
694 | |
695 | $_->meta->make_immutable( |
ec9e38e5 |
696 | inline_constructor => 0, |
6c2f6b5c |
697 | constructor_name => "_new", |
45582002 |
698 | inline_accessors => 0, |
0b9372a2 |
699 | ) for qw/ |
1d68af04 |
700 | Class::MOP::Package |
701 | Class::MOP::Module |
702 | Class::MOP::Class |
703 | |
0b9372a2 |
704 | Class::MOP::Attribute |
1d68af04 |
705 | Class::MOP::Method |
706 | Class::MOP::Instance |
707 | |
708 | Class::MOP::Object |
0b9372a2 |
709 | |
565f0cbb |
710 | Class::MOP::Method::Generated |
29d4e92a |
711 | Class::MOP::Method::Inlined |
1d68af04 |
712 | |
ba38bf08 |
713 | Class::MOP::Method::Accessor |
1d68af04 |
714 | Class::MOP::Method::Constructor |
715 | Class::MOP::Method::Wrapped |
59b51046 |
716 | |
717 | Class::MOP::Method::Meta |
0b9372a2 |
718 | /; |
b6164407 |
719 | |
9b871d79 |
720 | $_->meta->make_immutable( |
721 | inline_constructor => 0, |
722 | constructor_name => undef, |
723 | inline_accessors => 0, |
724 | ) for qw/ |
725 | Class::MOP::Mixin |
726 | Class::MOP::Mixin::AttributeCore |
727 | Class::MOP::Mixin::HasAttributes |
728 | Class::MOP::Mixin::HasMethods |
729 | /; |
730 | |
94b19069 |
731 | 1; |
732 | |
733 | __END__ |
734 | |
735 | =pod |
736 | |
1d68af04 |
737 | =head1 NAME |
94b19069 |
738 | |
739 | Class::MOP - A Meta Object Protocol for Perl 5 |
740 | |
5b60bf98 |
741 | =head1 DESCRIPTION |
94b19069 |
742 | |
127d39a7 |
743 | This module is a fully functioning meta object protocol for the |
1d68af04 |
744 | Perl 5 object system. It makes no attempt to change the behavior or |
745 | characteristics of the Perl 5 object system, only to create a |
27e31eaf |
746 | protocol for its manipulation and introspection. |
94b19069 |
747 | |
828ecf13 |
748 | That said, it does attempt to create the tools for building a rich set |
749 | of extensions to the Perl 5 object system. Every attempt has been made |
750 | to abide by the spirit of the Perl 5 object system that we all know |
751 | and love. |
94b19069 |
752 | |
828ecf13 |
753 | This documentation is sparse on conceptual details. We suggest looking |
754 | at the items listed in the L<SEE ALSO> section for more |
755 | information. In particular the book "The Art of the Meta Object |
756 | Protocol" was very influential in the development of this system. |
40483095 |
757 | |
bfe4d0fc |
758 | =head2 What is a Meta Object Protocol? |
759 | |
1d68af04 |
760 | A meta object protocol is an API to an object system. |
bfe4d0fc |
761 | |
828ecf13 |
762 | To be more specific, it abstracts the components of an object system |
763 | (classes, object, methods, object attributes, etc.). These |
764 | abstractions can then be used to inspect and manipulate the object |
765 | system which they describe. |
bfe4d0fc |
766 | |
1d68af04 |
767 | It can be said that there are two MOPs for any object system; the |
828ecf13 |
768 | implicit MOP and the explicit MOP. The implicit MOP handles things |
1d68af04 |
769 | like method dispatch or inheritance, which happen automatically as |
770 | part of how the object system works. The explicit MOP typically |
771 | handles the introspection/reflection features of the object system. |
bfe4d0fc |
772 | |
828ecf13 |
773 | All object systems have implicit MOPs. Without one, they would not |
5b60bf98 |
774 | work. Explicit MOPs are much less common, and depending on the |
775 | language can vary from restrictive (Reflection in Java or C#) to wide |
776 | open (CLOS is a perfect example). |
e16da3e6 |
777 | |
828ecf13 |
778 | =head2 Yet Another Class Builder! Why? |
779 | |
780 | This is B<not> a class builder so much as a I<class builder |
781 | B<builder>>. The intent is that an end user will not use this module |
782 | directly, but instead this module is used by module authors to build |
783 | extensions and features onto the Perl 5 object system. |
784 | |
785 | This system is used by L<Moose>, which supplies a powerful class |
786 | builder system built entirely on top of C<Class::MOP>. |
e16da3e6 |
787 | |
94b19069 |
788 | =head2 Who is this module for? |
789 | |
828ecf13 |
790 | This module is for anyone who has ever created or wanted to create a |
791 | module for the Class:: namespace. The tools which this module provides |
792 | make doing complex Perl 5 wizardry simpler, by removing such barriers |
793 | as the need to hack symbol tables, or understand the fine details of |
794 | method dispatch. |
94b19069 |
795 | |
bfe4d0fc |
796 | =head2 What changes do I have to make to use this module? |
797 | |
828ecf13 |
798 | This module was designed to be as unintrusive as possible. Many of its |
5b60bf98 |
799 | features are accessible without B<any> change to your existing |
828ecf13 |
800 | code. It is meant to be a compliment to your existing code and not an |
801 | intrusion on your code base. Unlike many other B<Class::> modules, |
802 | this module B<does not> require you subclass it, or even that you |
803 | C<use> it in within your module's package. |
bfe4d0fc |
804 | |
1d68af04 |
805 | The only features which requires additions to your code are the |
2eb717d5 |
806 | attribute handling and instance construction features, and these are |
1d68af04 |
807 | both completely optional features. The only reason for this is because |
808 | Perl 5's object system does not actually have these features built |
2eb717d5 |
809 | in. More information about this feature can be found below. |
bfe4d0fc |
810 | |
828ecf13 |
811 | =head2 About Performance |
812 | |
5b60bf98 |
813 | It is a common misconception that explicit MOPs are a performance hit. |
828ecf13 |
814 | This is not a universal truth, it is a side-effect of some specific |
815 | implementations. For instance, using Java reflection is slow because |
816 | the JVM cannot take advantage of any compiler optimizations, and the |
817 | JVM has to deal with much more runtime type information as well. |
bfe4d0fc |
818 | |
828ecf13 |
819 | Reflection in C# is marginally better as it was designed into the |
820 | language and runtime (the CLR). In contrast, CLOS (the Common Lisp |
821 | Object System) was built to support an explicit MOP, and so |
822 | performance is tuned for it. |
1d68af04 |
823 | |
828ecf13 |
824 | This library in particular does its absolute best to avoid putting |
1d68af04 |
825 | B<any> drain at all upon your code's performance. In fact, by itself |
828ecf13 |
826 | it does nothing to affect your existing code. So you only pay for what |
827 | you actually use. |
bfe4d0fc |
828 | |
550d56db |
829 | =head2 About Metaclass compatibility |
830 | |
1d68af04 |
831 | This module makes sure that all metaclasses created are both upwards |
832 | and downwards compatible. The topic of metaclass compatibility is |
833 | highly esoteric and is something only encountered when doing deep and |
834 | involved metaclass hacking. There are two basic kinds of metaclass |
835 | incompatibility; upwards and downwards. |
550d56db |
836 | |
1d68af04 |
837 | Upwards metaclass compatibility means that the metaclass of a |
838 | given class is either the same as (or a subclass of) all of the |
550d56db |
839 | class's ancestors. |
840 | |
1d68af04 |
841 | Downward metaclass compatibility means that the metaclasses of a |
828ecf13 |
842 | given class's ancestors are all either the same as (or a subclass |
550d56db |
843 | of) that metaclass. |
844 | |
1d68af04 |
845 | Here is a diagram showing a set of two classes (C<A> and C<B>) and |
846 | two metaclasses (C<Meta::A> and C<Meta::B>) which have correct |
550d56db |
847 | metaclass compatibility both upwards and downwards. |
848 | |
849 | +---------+ +---------+ |
850 | | Meta::A |<----| Meta::B | <....... (instance of ) |
1d68af04 |
851 | +---------+ +---------+ <------- (inherits from) |
550d56db |
852 | ^ ^ |
853 | : : |
854 | +---------+ +---------+ |
855 | | A |<----| B | |
856 | +---------+ +---------+ |
857 | |
3ab5cf4a |
858 | In actuality, I<all> of a class's metaclasses must be compatible, |
859 | not just the class metaclass. That includes the instance, attribute, |
860 | and method metaclasses, as well as the constructor and destructor |
861 | classes. |
862 | |
863 | C<Class::MOP> will attempt to fix some simple types of |
864 | incompatibilities. If all the metaclasses for the parent class are |
865 | I<subclasses> of the child's metaclasses then we can simply replace |
866 | the child's metaclasses with the parent's. In addition, if the child |
867 | is missing a metaclass that the parent has, we can also just make the |
868 | child use the parent's metaclass. |
869 | |
1d68af04 |
870 | As I said this is a highly esoteric topic and one you will only run |
828ecf13 |
871 | into if you do a lot of subclassing of L<Class::MOP::Class>. If you |
872 | are interested in why this is an issue see the paper I<Uniform and |
873 | safe metaclass composition> linked to in the L<SEE ALSO> section of |
874 | this document. |
550d56db |
875 | |
aa448b16 |
876 | =head2 Using custom metaclasses |
877 | |
828ecf13 |
878 | Always use the L<metaclass> pragma when using a custom metaclass, this |
5b60bf98 |
879 | will ensure the proper initialization order and not accidentally |
880 | create an incorrect type of metaclass for you. This is a very rare |
881 | problem, and one which can only occur if you are doing deep metaclass |
aa448b16 |
882 | programming. So in other words, don't worry about it. |
883 | |
828ecf13 |
884 | Note that if you're using L<Moose> we encourage you to I<not> use |
885 | L<metaclass> pragma, and instead use L<Moose::Util::MetaRole> to apply |
886 | roles to a class's metaclasses. This topic is covered at length in |
887 | various L<Moose::Cookbook> recipes. |
888 | |
94b19069 |
889 | =head1 PROTOCOLS |
890 | |
828ecf13 |
891 | The meta-object protocol is divided into 4 main sub-protocols: |
94b19069 |
892 | |
828ecf13 |
893 | =head2 The Class protocol |
94b19069 |
894 | |
1d68af04 |
895 | This provides a means of manipulating and introspecting a Perl 5 |
828ecf13 |
896 | class. It handles symbol table hacking for you, and provides a rich |
897 | set of methods that go beyond simple package introspection. |
94b19069 |
898 | |
552e3d24 |
899 | See L<Class::MOP::Class> for more details. |
900 | |
828ecf13 |
901 | =head2 The Attribute protocol |
94b19069 |
902 | |
828ecf13 |
903 | This provides a consistent representation for an attribute of a Perl 5 |
904 | class. Since there are so many ways to create and handle attributes in |
905 | Perl 5 OO, the Attribute protocol provide as much of a unified |
906 | approach as possible. Of course, you are always free to extend this |
907 | protocol by subclassing the appropriate classes. |
94b19069 |
908 | |
552e3d24 |
909 | See L<Class::MOP::Attribute> for more details. |
910 | |
828ecf13 |
911 | =head2 The Method protocol |
94b19069 |
912 | |
828ecf13 |
913 | This provides a means of manipulating and introspecting methods in the |
914 | Perl 5 object system. As with attributes, there are many ways to |
1d68af04 |
915 | approach this topic, so we try to keep it pretty basic, while still |
94b19069 |
916 | making it possible to extend the system in many ways. |
917 | |
552e3d24 |
918 | See L<Class::MOP::Method> for more details. |
94b19069 |
919 | |
828ecf13 |
920 | =head2 The Instance protocol |
127d39a7 |
921 | |
828ecf13 |
922 | This provides a layer of abstraction for creating object instances. |
923 | Since the other layers use this protocol, it is relatively easy to |
924 | change the type of your instances from the default hash reference to |
925 | some other type of reference. Several examples are provided in the |
926 | F<examples/> directory included in this distribution. |
127d39a7 |
927 | |
928 | See L<Class::MOP::Instance> for more details. |
929 | |
be7677c7 |
930 | =head1 FUNCTIONS |
931 | |
828ecf13 |
932 | Note that this module does not export any constants or functions. |
933 | |
c1d5345a |
934 | =head2 Constants |
935 | |
936 | =over 4 |
937 | |
828ecf13 |
938 | =item I<Class::MOP::IS_RUNNING_ON_5_10> |
c1d5345a |
939 | |
828ecf13 |
940 | We set this constant depending on what version perl we are on, this |
941 | allows us to take advantage of new 5.10 features and stay backwards |
5b60bf98 |
942 | compatible. |
c1d5345a |
943 | |
944 | =back |
945 | |
448b6e55 |
946 | =head2 Utility functions |
947 | |
bd07fbdb |
948 | Note that these are all called as B<functions, not methods>. |
081a927b |
949 | |
448b6e55 |
950 | =over 4 |
951 | |
4154c4d0 |
952 | =item B<Class::MOP::load_class($class_name, \%options?)> |
448b6e55 |
953 | |
9d441c23 |
954 | This will load the specified C<$class_name>, if it is not already |
955 | loaded (as reported by C<is_class_loaded>). This function can be used |
828ecf13 |
956 | in place of tricks like C<eval "use $module"> or using C<require> |
7716a8f9 |
957 | unconditionally. |
448b6e55 |
958 | |
674d9359 |
959 | If the module cannot be loaded, an exception is thrown. |
960 | |
4154c4d0 |
961 | You can pass a hash reference with options as second argument. The |
962 | only option currently recognised is C<-version>, which will ensure |
963 | that the loaded class has at least the required version. |
964 | |
965 | See also L</Class Loading Options>. |
966 | |
78527c84 |
967 | For historical reasons, this function explicitly returns a true value. |
674d9359 |
968 | |
4154c4d0 |
969 | =item B<Class::MOP::is_class_loaded($class_name, \%options?)> |
448b6e55 |
970 | |
15ab5451 |
971 | Returns a boolean indicating whether or not C<$class_name> has been |
972 | loaded. |
448b6e55 |
973 | |
828ecf13 |
974 | This does a basic check of the symbol table to try and determine as |
975 | best it can if the C<$class_name> is loaded, it is probably correct |
976 | about 99% of the time, but it can be fooled into reporting false |
9d441c23 |
977 | positives. In particular, loading any of the core L<IO> modules will |
978 | cause most of the rest of the core L<IO> modules to falsely report |
979 | having been loaded, due to the way the base L<IO> module works. |
448b6e55 |
980 | |
4154c4d0 |
981 | You can pass a hash reference with options as second argument. The |
982 | only option currently recognised is C<-version>, which will ensure |
983 | that the loaded class has at least the required version. |
984 | |
985 | See also L</Class Loading Options>. |
986 | |
cdac22cc |
987 | =item B<Class::MOP::get_code_info($code)> |
988 | |
989 | This function returns two values, the name of the package the C<$code> |
990 | is from and the name of the C<$code> itself. This is used by several |
5b60bf98 |
991 | elements of the MOP to determine where a given C<$code> reference is |
cdac22cc |
992 | from. |
993 | |
44ba77a3 |
994 | =item B<Class::MOP::class_of($instance_or_class_name)> |
995 | |
3fa5b3f9 |
996 | This will return the metaclass of the given instance or class name. If the |
997 | class lacks a metaclass, no metaclass will be initialized, and C<undef> will be |
998 | returned. |
44ba77a3 |
999 | |
828ecf13 |
1000 | =item B<Class::MOP::check_package_cache_flag($pkg)> |
e0e4674a |
1001 | |
bd07fbdb |
1002 | B<NOTE: DO NOT USE THIS FUNCTION, IT IS FOR INTERNAL USE ONLY!> |
1003 | |
828ecf13 |
1004 | This will return an integer that is managed by L<Class::MOP::Class> to |
1005 | determine if a module's symbol table has been altered. |
127d39a7 |
1006 | |
828ecf13 |
1007 | In Perl 5.10 or greater, this flag is package specific. However in |
1008 | versions prior to 5.10, this will use the C<PL_sub_generation> |
1009 | variable which is not package specific. |
127d39a7 |
1010 | |
828ecf13 |
1011 | =item B<Class::MOP::load_first_existing_class(@class_names)> |
063ad0c5 |
1012 | |
4154c4d0 |
1013 | =item B<Class::MOP::load_first_existing_class($classA, \%optionsA?, $classB, ...)> |
1014 | |
063ad0c5 |
1015 | B<NOTE: DO NOT USE THIS FUNCTION, IT IS FOR INTERNAL USE ONLY!> |
1016 | |
1017 | Given a list of class names, this function will attempt to load each |
1018 | one in turn. |
1019 | |
828ecf13 |
1020 | If it finds a class it can load, it will return that class' name. If |
1021 | none of the classes can be loaded, it will throw an exception. |
063ad0c5 |
1022 | |
4154c4d0 |
1023 | Additionally, you can pass a hash reference with options after each |
1024 | class name. Currently, only C<-version> is recognised and will ensure |
1025 | that the loaded class has at least the required version. If the class |
1026 | version is not sufficient, an exception will be raised. |
1027 | |
1028 | See also L</Class Loading Options>. |
1029 | |
448b6e55 |
1030 | =back |
1031 | |
1032 | =head2 Metaclass cache functions |
1033 | |
6c842677 |
1034 | Class::MOP holds a cache of metaclasses. The following are functions |
1d68af04 |
1035 | (B<not methods>) which can be used to access that cache. It is not |
6c842677 |
1036 | recommended that you mess with these. Bad things could happen, but if |
1037 | you are brave and willing to risk it: go for it! |
be7677c7 |
1038 | |
1039 | =over 4 |
1040 | |
828ecf13 |
1041 | =item B<Class::MOP::get_all_metaclasses> |
be7677c7 |
1042 | |
6c842677 |
1043 | This will return a hash of all the metaclass instances that have |
828ecf13 |
1044 | been cached by L<Class::MOP::Class>, keyed by the package name. |
b9d9fc0b |
1045 | |
828ecf13 |
1046 | =item B<Class::MOP::get_all_metaclass_instances> |
be7677c7 |
1047 | |
6c842677 |
1048 | This will return a list of all the metaclass instances that have |
828ecf13 |
1049 | been cached by L<Class::MOP::Class>. |
b9d9fc0b |
1050 | |
828ecf13 |
1051 | =item B<Class::MOP::get_all_metaclass_names> |
be7677c7 |
1052 | |
6c842677 |
1053 | This will return a list of all the metaclass names that have |
828ecf13 |
1054 | been cached by L<Class::MOP::Class>. |
b9d9fc0b |
1055 | |
828ecf13 |
1056 | =item B<Class::MOP::get_metaclass_by_name($name)> |
be7677c7 |
1057 | |
828ecf13 |
1058 | This will return a cached L<Class::MOP::Class> instance, or nothing |
6c842677 |
1059 | if no metaclass exists with that C<$name>. |
127d39a7 |
1060 | |
828ecf13 |
1061 | =item B<Class::MOP::store_metaclass_by_name($name, $meta)> |
be7677c7 |
1062 | |
127d39a7 |
1063 | This will store a metaclass in the cache at the supplied C<$key>. |
1064 | |
828ecf13 |
1065 | =item B<Class::MOP::weaken_metaclass($name)> |
be7677c7 |
1066 | |
6c842677 |
1067 | In rare cases (e.g. anonymous metaclasses) it is desirable to |
1068 | store a weakened reference in the metaclass cache. This |
1069 | function will weaken the reference to the metaclass stored |
1070 | in C<$name>. |
127d39a7 |
1071 | |
73dad89f |
1072 | =item B<Class::MOP::metaclass_is_weak($name)> |
1073 | |
1074 | Returns true if the metaclass for C<$name> has been weakened |
1075 | (via C<weaken_metaclass>). |
1076 | |
828ecf13 |
1077 | =item B<Class::MOP::does_metaclass_exist($name)> |
be7677c7 |
1078 | |
828ecf13 |
1079 | This will return true of there exists a metaclass stored in the |
6c842677 |
1080 | C<$name> key, and return false otherwise. |
127d39a7 |
1081 | |
828ecf13 |
1082 | =item B<Class::MOP::remove_metaclass_by_name($name)> |
be7677c7 |
1083 | |
6c842677 |
1084 | This will remove the metaclass stored in the C<$name> key. |
127d39a7 |
1085 | |
be7677c7 |
1086 | =back |
1087 | |
4154c4d0 |
1088 | =head2 Class Loading Options |
1089 | |
1090 | =over 4 |
1091 | |
1092 | =item -version |
1093 | |
1094 | Can be used to pass a minimum required version that will be checked |
1095 | against the class version after it was loaded. |
1096 | |
1097 | =back |
1098 | |
552e3d24 |
1099 | =head1 SEE ALSO |
8b978dd5 |
1100 | |
552e3d24 |
1101 | =head2 Books |
8b978dd5 |
1102 | |
1d68af04 |
1103 | There are very few books out on Meta Object Protocols and Metaclasses |
1104 | because it is such an esoteric topic. The following books are really |
1105 | the only ones I have found. If you know of any more, B<I<please>> |
a2e85e6c |
1106 | email me and let me know, I would love to hear about them. |
1107 | |
8b978dd5 |
1108 | =over 4 |
1109 | |
15ab5451 |
1110 | =item I<The Art of the Meta Object Protocol> |
8b978dd5 |
1111 | |
15ab5451 |
1112 | =item I<Advances in Object-Oriented Metalevel Architecture and Reflection> |
8b978dd5 |
1113 | |
15ab5451 |
1114 | =item I<Putting MetaClasses to Work> |
b51af7f9 |
1115 | |
15ab5451 |
1116 | =item I<Smalltalk: The Language> |
a2e85e6c |
1117 | |
94b19069 |
1118 | =back |
1119 | |
550d56db |
1120 | =head2 Papers |
1121 | |
1122 | =over 4 |
1123 | |
15ab5451 |
1124 | =item "Uniform and safe metaclass composition" |
550d56db |
1125 | |
1d68af04 |
1126 | An excellent paper by the people who brought us the original Traits paper. |
1127 | This paper is on how Traits can be used to do safe metaclass composition, |
1128 | and offers an excellent introduction section which delves into the topic of |
550d56db |
1129 | metaclass compatibility. |
1130 | |
1131 | L<http://www.iam.unibe.ch/~scg/Archive/Papers/Duca05ySafeMetaclassTrait.pdf> |
1132 | |
15ab5451 |
1133 | =item "Safe Metaclass Programming" |
550d56db |
1134 | |
1d68af04 |
1135 | This paper seems to precede the above paper, and propose a mix-in based |
1136 | approach as opposed to the Traits based approach. Both papers have similar |
1137 | information on the metaclass compatibility problem space. |
550d56db |
1138 | |
1139 | L<http://citeseer.ist.psu.edu/37617.html> |
1140 | |
1141 | =back |
1142 | |
552e3d24 |
1143 | =head2 Prior Art |
8b978dd5 |
1144 | |
1145 | =over 4 |
1146 | |
7184ca14 |
1147 | =item The Perl 6 MetaModel work in the Pugs project |
8b978dd5 |
1148 | |
1149 | =over 4 |
1150 | |
02615ef0 |
1151 | =item L<http://svn.openfoundry.org/pugs/misc/Perl-MetaModel/> |
8b978dd5 |
1152 | |
4c706fe5 |
1153 | =item L<http://github.com/perl6/p5-modules/tree/master/Perl6-ObjectSpace/> |
8b978dd5 |
1154 | |
1155 | =back |
1156 | |
94b19069 |
1157 | =back |
1158 | |
1d68af04 |
1159 | =head2 Articles |
f8dfcfb7 |
1160 | |
1161 | =over 4 |
1162 | |
1d68af04 |
1163 | =item CPAN Module Review of Class::MOP |
f8dfcfb7 |
1164 | |
1165 | L<http://www.oreillynet.com/onlamp/blog/2006/06/cpan_module_review_classmop.html> |
1166 | |
1167 | =back |
1168 | |
a2e85e6c |
1169 | =head1 SIMILAR MODULES |
1170 | |
1d68af04 |
1171 | As I have said above, this module is a class-builder-builder, so it is |
1172 | not the same thing as modules like L<Class::Accessor> and |
1173 | L<Class::MethodMaker>. That being said there are very few modules on CPAN |
1174 | with similar goals to this module. The one I have found which is most |
1175 | like this module is L<Class::Meta>, although it's philosophy and the MOP it |
1176 | creates are very different from this modules. |
94b19069 |
1177 | |
a2e85e6c |
1178 | =head1 BUGS |
1179 | |
1d68af04 |
1180 | All complex software has bugs lurking in it, and this module is no |
53702399 |
1181 | exception. |
1182 | |
1183 | Please report any bugs to C<bug-class-mop@rt.cpan.org>, or through the |
1184 | web interface at L<http://rt.cpan.org>. |
1185 | |
1186 | You can also discuss feature requests or possible bugs on the Moose |
1187 | mailing list (moose@perl.org) or on IRC at |
1188 | L<irc://irc.perl.org/#moose>. |
a2e85e6c |
1189 | |
1190 | =head1 ACKNOWLEDGEMENTS |
1191 | |
1192 | =over 4 |
1193 | |
b9d9fc0b |
1194 | =item Rob Kinyon |
a2e85e6c |
1195 | |
1d68af04 |
1196 | Thanks to Rob for actually getting the development of this module kick-started. |
a2e85e6c |
1197 | |
1198 | =back |
1199 | |
1a09d9cc |
1200 | =head1 AUTHORS |
94b19069 |
1201 | |
a2e85e6c |
1202 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
552e3d24 |
1203 | |
9c8cda90 |
1204 | B<with contributions from:> |
1205 | |
1206 | Brandon (blblack) Black |
1207 | |
4f116037 |
1208 | Florian (rafl) Ragwitz |
1209 | |
9c8cda90 |
1210 | Guillermo (groditi) Roditi |
1211 | |
53702399 |
1212 | Dave (autarch) Rolsky |
1213 | |
9195ddff |
1214 | Matt (mst) Trout |
1215 | |
9c8cda90 |
1216 | Rob (robkinyon) Kinyon |
1217 | |
1218 | Yuval (nothingmuch) Kogman |
1a09d9cc |
1219 | |
f430cfa4 |
1220 | Scott (konobi) McWhirter |
1221 | |
20f5ccef |
1222 | Dylan Hardison |
1223 | |
94b19069 |
1224 | =head1 COPYRIGHT AND LICENSE |
1225 | |
3e2c8600 |
1226 | Copyright 2006-2010 by Infinity Interactive, Inc. |
94b19069 |
1227 | |
1228 | L<http://www.iinteractive.com> |
1229 | |
1230 | This library is free software; you can redistribute it and/or modify |
1d68af04 |
1231 | it under the same terms as Perl itself. |
94b19069 |
1232 | |
1233 | =cut |