Commit | Line | Data |
94b19069 |
1 | |
2 | package Class::MOP; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
3cf322a0 |
7 | use MRO::Compat; |
8 | |
4c105333 |
9 | use Carp 'confess'; |
10 | use Scalar::Util 'weaken'; |
8b978dd5 |
11 | |
2eb717d5 |
12 | use Class::MOP::Class; |
13 | use Class::MOP::Attribute; |
14 | use Class::MOP::Method; |
15 | |
c23184fc |
16 | use Class::MOP::Immutable; |
857f87a7 |
17 | |
b1f5f41d |
18 | BEGIN { |
70ad0655 |
19 | |
2e5c1a3f |
20 | our $VERSION = '0.65'; |
b1f5f41d |
21 | our $AUTHORITY = 'cpan:STEVAN'; |
22 | |
11b56828 |
23 | *IS_RUNNING_ON_5_10 = ($] < 5.009_005) |
24 | ? sub () { 0 } |
4c105333 |
25 | : sub () { 1 }; |
46b23b44 |
26 | |
4c105333 |
27 | # NOTE: |
28 | # we may not use this yet, but once |
29 | # the get_code_info XS gets merged |
30 | # upstream to it, we will always use |
31 | # it. But for now it is just kinda |
32 | # extra overhead. |
33 | # - SL |
34 | require Sub::Identify; |
35 | |
36 | # stash these for a sec, and see how things go |
37 | my $_PP_subname = sub { $_[1] }; |
a982eca7 |
38 | my $_PP_get_code_info = \&Sub::Identify::get_code_info; |
4c105333 |
39 | |
e2d4fc55 |
40 | if ($ENV{CLASS_MOP_NO_XS}) { |
4c105333 |
41 | # NOTE: |
42 | # this is if you really want things |
43 | # to be slow, then you can force the |
44 | # no-XS rule this way, otherwise we |
45 | # make an effort to load as much of |
46 | # the XS as possible. |
47 | # - SL |
48 | no warnings 'prototype', 'redefine'; |
6c34db07 |
49 | |
50 | unless (IS_RUNNING_ON_5_10()) { |
51 | # get this from MRO::Compat ... |
52 | *check_package_cache_flag = \&MRO::Compat::__get_pkg_gen_pp; |
53 | } |
54 | else { |
55 | # NOTE: |
56 | # but if we are running 5.10 |
57 | # there is no need to use the |
58 | # Pure Perl version since we |
59 | # can use the built in mro |
60 | # version instead. |
61 | # - SL |
62 | *check_package_cache_flag = \&mro::get_pkg_gen; |
63 | } |
4c105333 |
64 | # our own version of Sub::Name |
65 | *subname = $_PP_subname; |
66 | # and the Sub::Identify version of the get_code_info |
67 | *get_code_info = $_PP_get_code_info; |
68 | } |
69 | else { |
70 | # now try our best to get as much |
71 | # of the XS loaded as possible |
72 | { |
73 | local $@; |
74 | eval { |
75 | require XSLoader; |
76 | XSLoader::load( 'Class::MOP', $VERSION ); |
77 | }; |
78 | die $@ if $@ && $@ !~ /object version|loadable object/; |
79 | |
80 | # okay, so the XS failed to load, so |
81 | # use the pure perl one instead. |
82 | *get_code_info = $_PP_get_code_info if $@; |
83 | } |
84 | |
85 | # get it from MRO::Compat |
86 | *check_package_cache_flag = \&mro::get_pkg_gen; |
87 | |
88 | # now try and load the Sub::Name |
89 | # module and use that as a means |
90 | # for naming our CVs, if not, we |
91 | # use the workaround instead. |
92 | if ( eval { require Sub::Name } ) { |
6c34db07 |
93 | *subname = \&Sub::Name::subname; |
4c105333 |
94 | } |
95 | else { |
96 | *subname = $_PP_subname; |
97 | } |
98 | } |
b1f5f41d |
99 | } |
e0e4674a |
100 | |
be7677c7 |
101 | { |
102 | # Metaclasses are singletons, so we cache them here. |
103 | # there is no need to worry about destruction though |
104 | # because they should die only when the program dies. |
105 | # After all, do package definitions even get reaped? |
1d68af04 |
106 | my %METAS; |
107 | |
108 | # means of accessing all the metaclasses that have |
be7677c7 |
109 | # been initialized thus far (for mugwumps obj browser) |
1d68af04 |
110 | sub get_all_metaclasses { %METAS } |
111 | sub get_all_metaclass_instances { values %METAS } |
112 | sub get_all_metaclass_names { keys %METAS } |
be7677c7 |
113 | sub get_metaclass_by_name { $METAS{$_[0]} } |
1d68af04 |
114 | sub store_metaclass_by_name { $METAS{$_[0]} = $_[1] } |
115 | sub weaken_metaclass { weaken($METAS{$_[0]}) } |
be7677c7 |
116 | sub does_metaclass_exist { exists $METAS{$_[0]} && defined $METAS{$_[0]} } |
1d68af04 |
117 | sub remove_metaclass_by_name { $METAS{$_[0]} = undef } |
118 | |
be7677c7 |
119 | # NOTE: |
1d68af04 |
120 | # We only cache metaclasses, meaning instances of |
121 | # Class::MOP::Class. We do not cache instance of |
be7677c7 |
122 | # Class::MOP::Package or Class::MOP::Module. Mostly |
1d68af04 |
123 | # because I don't yet see a good reason to do so. |
be7677c7 |
124 | } |
125 | |
448b6e55 |
126 | sub load_class { |
127 | my $class = shift; |
ab5e2f48 |
128 | |
129 | if (ref($class) || !defined($class) || !length($class)) { |
130 | my $display = defined($class) ? $class : 'undef'; |
131 | confess "Invalid class name ($display)"; |
132 | } |
133 | |
07940968 |
134 | # if the class is not already loaded in the symbol table.. |
135 | unless (is_class_loaded($class)) { |
136 | # require it |
137 | my $file = $class . '.pm'; |
138 | $file =~ s{::}{/}g; |
139 | eval { CORE::require($file) }; |
140 | confess "Could not load class ($class) because : $@" if $@; |
141 | } |
142 | |
143 | # initialize a metaclass if necessary |
448b6e55 |
144 | unless (does_metaclass_exist($class)) { |
145 | eval { Class::MOP::Class->initialize($class) }; |
1d68af04 |
146 | confess "Could not initialize class ($class) because : $@" if $@; |
448b6e55 |
147 | } |
07940968 |
148 | |
149 | return get_metaclass_by_name($class); |
448b6e55 |
150 | } |
151 | |
152 | sub is_class_loaded { |
c1d5345a |
153 | my $class = shift; |
26fcef27 |
154 | |
155 | return 0 if ref($class) || !defined($class) || !length($class); |
156 | |
157 | # walk the symbol table tree to avoid autovififying |
158 | # \*{${main::}{"Foo::"}} == \*main::Foo:: |
159 | |
160 | my $pack = \*::; |
161 | foreach my $part (split('::', $class)) { |
162 | return 0 unless exists ${$$pack}{"${part}::"}; |
163 | $pack = \*{${$$pack}{"${part}::"}}; |
c1d5345a |
164 | } |
26fcef27 |
165 | |
166 | # check for $VERSION or @ISA |
167 | return 1 if exists ${$$pack}{VERSION} |
168 | && defined *{${$$pack}{VERSION}}{SCALAR}; |
169 | return 1 if exists ${$$pack}{ISA} |
170 | && defined *{${$$pack}{ISA}}{ARRAY}; |
171 | |
172 | # check for any method |
173 | foreach ( keys %{$$pack} ) { |
174 | next if substr($_, -2, 2) eq '::'; |
d5be3722 |
175 | |
176 | my $glob = ${$$pack}{$_} || next; |
177 | |
9e275e86 |
178 | # constant subs |
d5be3722 |
179 | if ( IS_RUNNING_ON_5_10 ) { |
180 | return 1 if ref $glob eq 'SCALAR'; |
181 | } |
182 | |
183 | return 1 if defined *{$glob}{CODE}; |
26fcef27 |
184 | } |
185 | |
186 | # fail |
c1d5345a |
187 | return 0; |
448b6e55 |
188 | } |
189 | |
190 | |
aa448b16 |
191 | ## ---------------------------------------------------------------------------- |
192 | ## Setting up our environment ... |
193 | ## ---------------------------------------------------------------------------- |
1d68af04 |
194 | ## Class::MOP needs to have a few things in the global perl environment so |
aa448b16 |
195 | ## that it can operate effectively. Those things are done here. |
196 | ## ---------------------------------------------------------------------------- |
197 | |
3bf7644b |
198 | # ... nothing yet actually ;) |
8b978dd5 |
199 | |
b51af7f9 |
200 | ## ---------------------------------------------------------------------------- |
1d68af04 |
201 | ## Bootstrapping |
b51af7f9 |
202 | ## ---------------------------------------------------------------------------- |
1d68af04 |
203 | ## The code below here is to bootstrap our MOP with itself. This is also |
b51af7f9 |
204 | ## sometimes called "tying the knot". By doing this, we make it much easier |
205 | ## to extend the MOP through subclassing and such since now you can use the |
1d68af04 |
206 | ## MOP itself to extend itself. |
207 | ## |
b51af7f9 |
208 | ## Yes, I know, thats weird and insane, but it's a good thing, trust me :) |
1d68af04 |
209 | ## ---------------------------------------------------------------------------- |
727919c5 |
210 | |
1d68af04 |
211 | # We need to add in the meta-attributes here so that |
212 | # any subclass of Class::MOP::* will be able to |
727919c5 |
213 | # inherit them using &construct_instance |
214 | |
f0480c45 |
215 | ## -------------------------------------------------------- |
6d5355c3 |
216 | ## Class::MOP::Package |
727919c5 |
217 | |
6d5355c3 |
218 | Class::MOP::Package->meta->add_attribute( |
8683db0e |
219 | Class::MOP::Attribute->new('package' => ( |
b880e0de |
220 | reader => { |
1d68af04 |
221 | # NOTE: we need to do this in order |
222 | # for the instance meta-object to |
b880e0de |
223 | # not fall into meta-circular death |
1d68af04 |
224 | # |
ce2ae40f |
225 | # we just alias the original method |
1d68af04 |
226 | # rather than re-produce it here |
ce2ae40f |
227 | 'name' => \&Class::MOP::Package::name |
b880e0de |
228 | }, |
c23184fc |
229 | init_arg => 'package', |
727919c5 |
230 | )) |
231 | ); |
232 | |
a5e51f0b |
233 | Class::MOP::Package->meta->add_attribute( |
8683db0e |
234 | Class::MOP::Attribute->new('namespace' => ( |
a5e51f0b |
235 | reader => { |
56dcfc1a |
236 | # NOTE: |
ce2ae40f |
237 | # we just alias the original method |
238 | # rather than re-produce it here |
239 | 'namespace' => \&Class::MOP::Package::namespace |
a5e51f0b |
240 | }, |
2e877f58 |
241 | init_arg => undef, |
c4260b45 |
242 | default => sub { \undef } |
a5e51f0b |
243 | )) |
244 | ); |
245 | |
9d6dce77 |
246 | # NOTE: |
247 | # use the metaclass to construct the meta-package |
248 | # which is a superclass of the metaclass itself :P |
249 | Class::MOP::Package->meta->add_method('initialize' => sub { |
250 | my $class = shift; |
251 | my $package_name = shift; |
1d68af04 |
252 | $class->meta->new_object('package' => $package_name, @_); |
9d6dce77 |
253 | }); |
254 | |
f0480c45 |
255 | ## -------------------------------------------------------- |
256 | ## Class::MOP::Module |
257 | |
258 | # NOTE: |
1d68af04 |
259 | # yeah this is kind of stretching things a bit, |
f0480c45 |
260 | # but truthfully the version should be an attribute |
1d68af04 |
261 | # of the Module, the weirdness comes from having to |
262 | # stick to Perl 5 convention and store it in the |
263 | # $VERSION package variable. Basically if you just |
264 | # squint at it, it will look how you want it to look. |
f0480c45 |
265 | # Either as a package variable, or as a attribute of |
266 | # the metaclass, isn't abstraction great :) |
267 | |
268 | Class::MOP::Module->meta->add_attribute( |
8683db0e |
269 | Class::MOP::Attribute->new('version' => ( |
f0480c45 |
270 | reader => { |
ce2ae40f |
271 | # NOTE: |
272 | # we just alias the original method |
1d68af04 |
273 | # rather than re-produce it here |
ce2ae40f |
274 | 'version' => \&Class::MOP::Module::version |
f0480c45 |
275 | }, |
2e877f58 |
276 | init_arg => undef, |
c4260b45 |
277 | default => sub { \undef } |
f0480c45 |
278 | )) |
279 | ); |
280 | |
281 | # NOTE: |
1d68af04 |
282 | # By following the same conventions as version here, |
283 | # we are opening up the possibility that people can |
284 | # use the $AUTHORITY in non-Class::MOP modules as |
285 | # well. |
f0480c45 |
286 | |
287 | Class::MOP::Module->meta->add_attribute( |
8683db0e |
288 | Class::MOP::Attribute->new('authority' => ( |
f0480c45 |
289 | reader => { |
ce2ae40f |
290 | # NOTE: |
291 | # we just alias the original method |
1d68af04 |
292 | # rather than re-produce it here |
ce2ae40f |
293 | 'authority' => \&Class::MOP::Module::authority |
1d68af04 |
294 | }, |
2e877f58 |
295 | init_arg => undef, |
c4260b45 |
296 | default => sub { \undef } |
f0480c45 |
297 | )) |
298 | ); |
299 | |
300 | ## -------------------------------------------------------- |
6d5355c3 |
301 | ## Class::MOP::Class |
302 | |
727919c5 |
303 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
304 | Class::MOP::Attribute->new('attributes' => ( |
f7259199 |
305 | reader => { |
1d68af04 |
306 | # NOTE: we need to do this in order |
307 | # for the instance meta-object to |
308 | # not fall into meta-circular death |
309 | # |
ce2ae40f |
310 | # we just alias the original method |
1d68af04 |
311 | # rather than re-produce it here |
ce2ae40f |
312 | 'get_attribute_map' => \&Class::MOP::Class::get_attribute_map |
f7259199 |
313 | }, |
c23184fc |
314 | init_arg => 'attributes', |
727919c5 |
315 | default => sub { {} } |
316 | )) |
317 | ); |
318 | |
351bd7d4 |
319 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
320 | Class::MOP::Attribute->new('methods' => ( |
c23184fc |
321 | init_arg => 'methods', |
1d68af04 |
322 | reader => { |
ce2ae40f |
323 | # NOTE: |
324 | # we just alias the original method |
1d68af04 |
325 | # rather than re-produce it here |
ce2ae40f |
326 | 'get_method_map' => \&Class::MOP::Class::get_method_map |
92330ee2 |
327 | }, |
7855ddba |
328 | default => sub { {} } |
c4260b45 |
329 | )) |
330 | ); |
331 | |
332 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
333 | Class::MOP::Attribute->new('superclasses' => ( |
c23184fc |
334 | accessor => { |
335 | # NOTE: |
336 | # we just alias the original method |
1d68af04 |
337 | # rather than re-produce it here |
c23184fc |
338 | 'superclasses' => \&Class::MOP::Class::superclasses |
339 | }, |
2e877f58 |
340 | init_arg => undef, |
c23184fc |
341 | default => sub { \undef } |
342 | )) |
343 | ); |
344 | |
345 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
346 | Class::MOP::Attribute->new('attribute_metaclass' => ( |
1d68af04 |
347 | reader => { |
6d2118a4 |
348 | # NOTE: |
349 | # we just alias the original method |
1d68af04 |
350 | # rather than re-produce it here |
6d2118a4 |
351 | 'attribute_metaclass' => \&Class::MOP::Class::attribute_metaclass |
1d68af04 |
352 | }, |
c23184fc |
353 | init_arg => 'attribute_metaclass', |
351bd7d4 |
354 | default => 'Class::MOP::Attribute', |
355 | )) |
356 | ); |
357 | |
358 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
359 | Class::MOP::Attribute->new('method_metaclass' => ( |
1d68af04 |
360 | reader => { |
6d2118a4 |
361 | # NOTE: |
362 | # we just alias the original method |
1d68af04 |
363 | # rather than re-produce it here |
6d2118a4 |
364 | 'method_metaclass' => \&Class::MOP::Class::method_metaclass |
365 | }, |
c23184fc |
366 | init_arg => 'method_metaclass', |
1d68af04 |
367 | default => 'Class::MOP::Method', |
351bd7d4 |
368 | )) |
369 | ); |
370 | |
2bab2be6 |
371 | Class::MOP::Class->meta->add_attribute( |
8683db0e |
372 | Class::MOP::Attribute->new('instance_metaclass' => ( |
b880e0de |
373 | reader => { |
1d68af04 |
374 | # NOTE: we need to do this in order |
375 | # for the instance meta-object to |
376 | # not fall into meta-circular death |
377 | # |
ce2ae40f |
378 | # we just alias the original method |
1d68af04 |
379 | # rather than re-produce it here |
ce2ae40f |
380 | 'instance_metaclass' => \&Class::MOP::Class::instance_metaclass |
b880e0de |
381 | }, |
c23184fc |
382 | init_arg => 'instance_metaclass', |
1d68af04 |
383 | default => 'Class::MOP::Instance', |
2bab2be6 |
384 | )) |
385 | ); |
386 | |
9d6dce77 |
387 | # NOTE: |
1d68af04 |
388 | # we don't actually need to tie the knot with |
389 | # Class::MOP::Class here, it is actually handled |
390 | # within Class::MOP::Class itself in the |
391 | # construct_class_instance method. |
9d6dce77 |
392 | |
f0480c45 |
393 | ## -------------------------------------------------------- |
727919c5 |
394 | ## Class::MOP::Attribute |
395 | |
7b31baf4 |
396 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
397 | Class::MOP::Attribute->new('name' => ( |
c23184fc |
398 | init_arg => 'name', |
399 | reader => { |
1d68af04 |
400 | # NOTE: we need to do this in order |
401 | # for the instance meta-object to |
402 | # not fall into meta-circular death |
403 | # |
ce2ae40f |
404 | # we just alias the original method |
1d68af04 |
405 | # rather than re-produce it here |
ce2ae40f |
406 | 'name' => \&Class::MOP::Attribute::name |
b880e0de |
407 | } |
7b31baf4 |
408 | )) |
409 | ); |
410 | |
411 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
412 | Class::MOP::Attribute->new('associated_class' => ( |
c23184fc |
413 | init_arg => 'associated_class', |
414 | reader => { |
1d68af04 |
415 | # NOTE: we need to do this in order |
416 | # for the instance meta-object to |
417 | # not fall into meta-circular death |
418 | # |
ce2ae40f |
419 | # we just alias the original method |
1d68af04 |
420 | # rather than re-produce it here |
ce2ae40f |
421 | 'associated_class' => \&Class::MOP::Attribute::associated_class |
b880e0de |
422 | } |
7b31baf4 |
423 | )) |
424 | ); |
425 | |
426 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
427 | Class::MOP::Attribute->new('accessor' => ( |
c23184fc |
428 | init_arg => 'accessor', |
6d2118a4 |
429 | reader => { 'accessor' => \&Class::MOP::Attribute::accessor }, |
430 | predicate => { 'has_accessor' => \&Class::MOP::Attribute::has_accessor }, |
7b31baf4 |
431 | )) |
432 | ); |
433 | |
434 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
435 | Class::MOP::Attribute->new('reader' => ( |
c23184fc |
436 | init_arg => 'reader', |
6d2118a4 |
437 | reader => { 'reader' => \&Class::MOP::Attribute::reader }, |
438 | predicate => { 'has_reader' => \&Class::MOP::Attribute::has_reader }, |
7b31baf4 |
439 | )) |
440 | ); |
441 | |
442 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
443 | Class::MOP::Attribute->new('initializer' => ( |
0ab65f99 |
444 | init_arg => 'initializer', |
8ee74136 |
445 | reader => { 'initializer' => \&Class::MOP::Attribute::initializer }, |
446 | predicate => { 'has_initializer' => \&Class::MOP::Attribute::has_initializer }, |
0ab65f99 |
447 | )) |
448 | ); |
449 | |
450 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
451 | Class::MOP::Attribute->new('writer' => ( |
c23184fc |
452 | init_arg => 'writer', |
6d2118a4 |
453 | reader => { 'writer' => \&Class::MOP::Attribute::writer }, |
454 | predicate => { 'has_writer' => \&Class::MOP::Attribute::has_writer }, |
7b31baf4 |
455 | )) |
456 | ); |
457 | |
458 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
459 | Class::MOP::Attribute->new('predicate' => ( |
c23184fc |
460 | init_arg => 'predicate', |
6d2118a4 |
461 | reader => { 'predicate' => \&Class::MOP::Attribute::predicate }, |
462 | predicate => { 'has_predicate' => \&Class::MOP::Attribute::has_predicate }, |
7b31baf4 |
463 | )) |
464 | ); |
465 | |
466 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
467 | Class::MOP::Attribute->new('clearer' => ( |
c23184fc |
468 | init_arg => 'clearer', |
6d2118a4 |
469 | reader => { 'clearer' => \&Class::MOP::Attribute::clearer }, |
470 | predicate => { 'has_clearer' => \&Class::MOP::Attribute::has_clearer }, |
7d28758b |
471 | )) |
472 | ); |
473 | |
474 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
475 | Class::MOP::Attribute->new('builder' => ( |
1d68af04 |
476 | init_arg => 'builder', |
477 | reader => { 'builder' => \&Class::MOP::Attribute::builder }, |
478 | predicate => { 'has_builder' => \&Class::MOP::Attribute::has_builder }, |
479 | )) |
480 | ); |
481 | |
482 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
483 | Class::MOP::Attribute->new('init_arg' => ( |
c23184fc |
484 | init_arg => 'init_arg', |
6d2118a4 |
485 | reader => { 'init_arg' => \&Class::MOP::Attribute::init_arg }, |
486 | predicate => { 'has_init_arg' => \&Class::MOP::Attribute::has_init_arg }, |
7b31baf4 |
487 | )) |
488 | ); |
489 | |
490 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
491 | Class::MOP::Attribute->new('default' => ( |
c23184fc |
492 | init_arg => 'default', |
7b31baf4 |
493 | # default has a custom 'reader' method ... |
1d68af04 |
494 | predicate => { 'has_default' => \&Class::MOP::Attribute::has_default }, |
7b31baf4 |
495 | )) |
496 | ); |
497 | |
3545c727 |
498 | Class::MOP::Attribute->meta->add_attribute( |
8683db0e |
499 | Class::MOP::Attribute->new('associated_methods' => ( |
c23184fc |
500 | init_arg => 'associated_methods', |
501 | reader => { 'associated_methods' => \&Class::MOP::Attribute::associated_methods }, |
1d68af04 |
502 | default => sub { [] } |
3545c727 |
503 | )) |
504 | ); |
727919c5 |
505 | |
506 | # NOTE: (meta-circularity) |
507 | # This should be one of the last things done |
508 | # it will "tie the knot" with Class::MOP::Attribute |
1d68af04 |
509 | # so that it uses the attributes meta-objects |
510 | # to construct itself. |
727919c5 |
511 | Class::MOP::Attribute->meta->add_method('new' => sub { |
649efb63 |
512 | my ( $class, @args ) = @_; |
513 | |
514 | unshift @args, "name" if @args % 2 == 1; |
515 | my %options = @args; |
516 | |
517 | my $name = $options{name}; |
1d68af04 |
518 | |
727919c5 |
519 | (defined $name && $name) |
520 | || confess "You must provide a name for the attribute"; |
1d68af04 |
521 | $options{init_arg} = $name |
5659d76e |
522 | if not exists $options{init_arg}; |
1d68af04 |
523 | |
524 | if(exists $options{builder}){ |
525 | confess("builder must be a defined scalar value which is a method name") |
526 | if ref $options{builder} || !(defined $options{builder}); |
527 | confess("Setting both default and builder is not allowed.") |
528 | if exists $options{default}; |
8fe581e5 |
529 | } else { |
530 | (Class::MOP::Attribute::is_default_a_coderef(\%options)) |
531 | || confess("References are not allowed as default values, you must ". |
3c0a8087 |
532 | "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])") |
8fe581e5 |
533 | if exists $options{default} && ref $options{default}; |
1d68af04 |
534 | } |
8683db0e |
535 | |
5659d76e |
536 | # return the new object |
649efb63 |
537 | $class->meta->new_object(%options); |
5659d76e |
538 | }); |
539 | |
540 | Class::MOP::Attribute->meta->add_method('clone' => sub { |
a740253a |
541 | my $self = shift; |
1d68af04 |
542 | $self->meta->clone_object($self, @_); |
727919c5 |
543 | }); |
544 | |
f0480c45 |
545 | ## -------------------------------------------------------- |
b6164407 |
546 | ## Class::MOP::Method |
b6164407 |
547 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
548 | Class::MOP::Attribute->new('body' => ( |
c23184fc |
549 | init_arg => 'body', |
550 | reader => { 'body' => \&Class::MOP::Method::body }, |
b6164407 |
551 | )) |
552 | ); |
553 | |
4c105333 |
554 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
555 | Class::MOP::Attribute->new('package_name' => ( |
4c105333 |
556 | init_arg => 'package_name', |
557 | reader => { 'package_name' => \&Class::MOP::Method::package_name }, |
558 | )) |
559 | ); |
560 | |
561 | Class::MOP::Method->meta->add_attribute( |
8683db0e |
562 | Class::MOP::Attribute->new('name' => ( |
4c105333 |
563 | init_arg => 'name', |
564 | reader => { 'name' => \&Class::MOP::Method::name }, |
565 | )) |
566 | ); |
567 | |
568 | Class::MOP::Method->meta->add_method('wrap' => sub { |
5caf45ce |
569 | my ( $class, @args ) = @_; |
570 | |
571 | unshift @args, 'body' if @args % 2 == 1; |
572 | |
573 | my %options = @args; |
574 | my $code = $options{body}; |
4c105333 |
575 | |
9b522fc4 |
576 | ('CODE' eq ref($code)) |
4c105333 |
577 | || confess "You must supply a CODE reference to bless, not (" . ($code || 'undef') . ")"; |
578 | |
b38f3848 |
579 | ($options{package_name} && $options{name}) |
580 | || confess "You must supply the package_name and name parameters"; |
581 | |
4c105333 |
582 | # return the new object |
5caf45ce |
583 | $class->meta->new_object(%options); |
4c105333 |
584 | }); |
585 | |
586 | Class::MOP::Method->meta->add_method('clone' => sub { |
587 | my $self = shift; |
588 | $self->meta->clone_object($self, @_); |
589 | }); |
590 | |
b6164407 |
591 | ## -------------------------------------------------------- |
592 | ## Class::MOP::Method::Wrapped |
593 | |
594 | # NOTE: |
1d68af04 |
595 | # the way this item is initialized, this |
596 | # really does not follow the standard |
597 | # practices of attributes, but we put |
b6164407 |
598 | # it here for completeness |
599 | Class::MOP::Method::Wrapped->meta->add_attribute( |
8683db0e |
600 | Class::MOP::Attribute->new('modifier_table') |
b6164407 |
601 | ); |
602 | |
603 | ## -------------------------------------------------------- |
565f0cbb |
604 | ## Class::MOP::Method::Generated |
605 | |
606 | Class::MOP::Method::Generated->meta->add_attribute( |
8683db0e |
607 | Class::MOP::Attribute->new('is_inline' => ( |
565f0cbb |
608 | init_arg => 'is_inline', |
609 | reader => { 'is_inline' => \&Class::MOP::Method::Generated::is_inline }, |
4c105333 |
610 | default => 0, |
1d68af04 |
611 | )) |
565f0cbb |
612 | ); |
613 | |
4c105333 |
614 | Class::MOP::Method::Generated->meta->add_method('new' => sub { |
615 | my ($class, %options) = @_; |
b38f3848 |
616 | ($options{package_name} && $options{name}) |
617 | || confess "You must supply the package_name and name parameters"; |
4c105333 |
618 | my $self = $class->meta->new_object(%options); |
619 | $self->initialize_body; |
620 | $self; |
621 | }); |
622 | |
565f0cbb |
623 | ## -------------------------------------------------------- |
d90b42a6 |
624 | ## Class::MOP::Method::Accessor |
625 | |
626 | Class::MOP::Method::Accessor->meta->add_attribute( |
8683db0e |
627 | Class::MOP::Attribute->new('attribute' => ( |
c23184fc |
628 | init_arg => 'attribute', |
1d68af04 |
629 | reader => { |
630 | 'associated_attribute' => \&Class::MOP::Method::Accessor::associated_attribute |
d90b42a6 |
631 | }, |
1d68af04 |
632 | )) |
d90b42a6 |
633 | ); |
634 | |
635 | Class::MOP::Method::Accessor->meta->add_attribute( |
8683db0e |
636 | Class::MOP::Attribute->new('accessor_type' => ( |
c23184fc |
637 | init_arg => 'accessor_type', |
638 | reader => { 'accessor_type' => \&Class::MOP::Method::Accessor::accessor_type }, |
1d68af04 |
639 | )) |
d90b42a6 |
640 | ); |
641 | |
4c105333 |
642 | Class::MOP::Method::Accessor->meta->add_method('new' => sub { |
643 | my $class = shift; |
644 | my %options = @_; |
645 | |
646 | (exists $options{attribute}) |
647 | || confess "You must supply an attribute to construct with"; |
648 | |
649 | (exists $options{accessor_type}) |
650 | || confess "You must supply an accessor_type to construct with"; |
651 | |
652 | (Scalar::Util::blessed($options{attribute}) && $options{attribute}->isa('Class::MOP::Attribute')) |
653 | || confess "You must supply an attribute which is a 'Class::MOP::Attribute' instance"; |
654 | |
b38f3848 |
655 | ($options{package_name} && $options{name}) |
656 | || confess "You must supply the package_name and name parameters"; |
657 | |
4c105333 |
658 | # return the new object |
659 | my $self = $class->meta->new_object(%options); |
660 | |
661 | # we don't want this creating |
662 | # a cycle in the code, if not |
663 | # needed |
8683db0e |
664 | Scalar::Util::weaken($self->{'attribute'}); |
4c105333 |
665 | |
666 | $self->initialize_body; |
667 | |
668 | $self; |
669 | }); |
670 | |
d90b42a6 |
671 | |
672 | ## -------------------------------------------------------- |
673 | ## Class::MOP::Method::Constructor |
674 | |
675 | Class::MOP::Method::Constructor->meta->add_attribute( |
8683db0e |
676 | Class::MOP::Attribute->new('options' => ( |
c23184fc |
677 | init_arg => 'options', |
1d68af04 |
678 | reader => { |
679 | 'options' => \&Class::MOP::Method::Constructor::options |
d90b42a6 |
680 | }, |
4c105333 |
681 | default => sub { +{} } |
1d68af04 |
682 | )) |
d90b42a6 |
683 | ); |
684 | |
685 | Class::MOP::Method::Constructor->meta->add_attribute( |
8683db0e |
686 | Class::MOP::Attribute->new('associated_metaclass' => ( |
c23184fc |
687 | init_arg => 'metaclass', |
1d68af04 |
688 | reader => { |
689 | 'associated_metaclass' => \&Class::MOP::Method::Constructor::associated_metaclass |
690 | }, |
691 | )) |
d90b42a6 |
692 | ); |
693 | |
4c105333 |
694 | Class::MOP::Method::Constructor->meta->add_method('new' => sub { |
695 | my $class = shift; |
696 | my %options = @_; |
697 | |
698 | (Scalar::Util::blessed $options{metaclass} && $options{metaclass}->isa('Class::MOP::Class')) |
699 | || confess "You must pass a metaclass instance if you want to inline" |
700 | if $options{is_inline}; |
701 | |
b38f3848 |
702 | ($options{package_name} && $options{name}) |
703 | || confess "You must supply the package_name and name parameters"; |
704 | |
4c105333 |
705 | # return the new object |
706 | my $self = $class->meta->new_object(%options); |
707 | |
708 | # we don't want this creating |
709 | # a cycle in the code, if not |
710 | # needed |
8683db0e |
711 | Scalar::Util::weaken($self->{'associated_metaclass'}); |
4c105333 |
712 | |
713 | $self->initialize_body; |
714 | |
715 | $self; |
716 | }); |
717 | |
d90b42a6 |
718 | ## -------------------------------------------------------- |
86482605 |
719 | ## Class::MOP::Instance |
720 | |
721 | # NOTE: |
1d68af04 |
722 | # these don't yet do much of anything, but are just |
86482605 |
723 | # included for completeness |
724 | |
63d08a9e |
725 | #Class::MOP::Instance->meta->add_method('new' => sub { |
726 | # my $class = shift; |
727 | # my $options = $class->BUILDARGS($class); |
728 | # |
729 | # # return the new object |
730 | # my $self = $class->meta->new_object(%$options); |
731 | # |
732 | # # we don't want this creating |
733 | # # a cycle in the code, if not |
734 | # # needed |
735 | # Scalar::Util::weaken($self->{'associated_metaclass'}); |
736 | # |
737 | # $self->initialize_body; |
738 | # |
739 | # $self; |
740 | #}); |
741 | |
86482605 |
742 | Class::MOP::Instance->meta->add_attribute( |
63d08a9e |
743 | Class::MOP::Attribute->new('associated_metaclass') |
86482605 |
744 | ); |
745 | |
746 | Class::MOP::Instance->meta->add_attribute( |
8683db0e |
747 | Class::MOP::Attribute->new('slots') |
86482605 |
748 | ); |
749 | |
63d08a9e |
750 | Class::MOP::Instance->meta->add_attribute( |
751 | Class::MOP::Attribute->new('slot_hash') |
752 | ); |
753 | |
754 | |
86482605 |
755 | ## -------------------------------------------------------- |
f0480c45 |
756 | ## Now close all the Class::MOP::* classes |
4d47b77f |
757 | |
0b9372a2 |
758 | # NOTE: |
1d68af04 |
759 | # we don't need to inline the |
760 | # constructors or the accessors |
761 | # this only lengthens the compile |
762 | # time of the MOP, and gives us |
0b9372a2 |
763 | # no actual benefits. |
764 | |
765 | $_->meta->make_immutable( |
766 | inline_constructor => 0, |
767 | inline_accessors => 0, |
768 | ) for qw/ |
1d68af04 |
769 | Class::MOP::Package |
770 | Class::MOP::Module |
771 | Class::MOP::Class |
772 | |
0b9372a2 |
773 | Class::MOP::Attribute |
1d68af04 |
774 | Class::MOP::Method |
775 | Class::MOP::Instance |
776 | |
777 | Class::MOP::Object |
0b9372a2 |
778 | |
565f0cbb |
779 | Class::MOP::Method::Generated |
1d68af04 |
780 | |
ba38bf08 |
781 | Class::MOP::Method::Accessor |
1d68af04 |
782 | Class::MOP::Method::Constructor |
783 | Class::MOP::Method::Wrapped |
0b9372a2 |
784 | /; |
b6164407 |
785 | |
94b19069 |
786 | 1; |
787 | |
788 | __END__ |
789 | |
790 | =pod |
791 | |
1d68af04 |
792 | =head1 NAME |
94b19069 |
793 | |
794 | Class::MOP - A Meta Object Protocol for Perl 5 |
795 | |
94b19069 |
796 | =head1 DESCRIPTON |
797 | |
127d39a7 |
798 | This module is a fully functioning meta object protocol for the |
1d68af04 |
799 | Perl 5 object system. It makes no attempt to change the behavior or |
800 | characteristics of the Perl 5 object system, only to create a |
27e31eaf |
801 | protocol for its manipulation and introspection. |
94b19069 |
802 | |
1d68af04 |
803 | That said, it does attempt to create the tools for building a rich |
804 | set of extensions to the Perl 5 object system. Every attempt has been |
805 | made for these tools to keep to the spirit of the Perl 5 object |
94b19069 |
806 | system that we all know and love. |
807 | |
1d68af04 |
808 | This documentation is admittedly sparse on details, as time permits |
809 | I will try to improve them. For now, I suggest looking at the items |
810 | listed in the L<SEE ALSO> section for more information. In particular |
811 | the book "The Art of the Meta Object Protocol" was very influential |
40483095 |
812 | in the development of this system. |
813 | |
bfe4d0fc |
814 | =head2 What is a Meta Object Protocol? |
815 | |
1d68af04 |
816 | A meta object protocol is an API to an object system. |
bfe4d0fc |
817 | |
1d68af04 |
818 | To be more specific, it is a set of abstractions of the components of |
819 | an object system (typically things like; classes, object, methods, |
820 | object attributes, etc.). These abstractions can then be used to both |
bfe4d0fc |
821 | inspect and manipulate the object system which they describe. |
822 | |
1d68af04 |
823 | It can be said that there are two MOPs for any object system; the |
824 | implicit MOP, and the explicit MOP. The implicit MOP handles things |
825 | like method dispatch or inheritance, which happen automatically as |
826 | part of how the object system works. The explicit MOP typically |
827 | handles the introspection/reflection features of the object system. |
828 | All object systems have implicit MOPs, without one, they would not |
829 | work. Explict MOPs however as less common, and depending on the |
830 | language can vary from restrictive (Reflection in Java or C#) to |
831 | wide open (CLOS is a perfect example). |
bfe4d0fc |
832 | |
e16da3e6 |
833 | =head2 Yet Another Class Builder!! Why? |
834 | |
1d68af04 |
835 | This is B<not> a class builder so much as it is a I<class builder |
836 | B<builder>>. My intent is that an end user does not use this module |
837 | directly, but instead this module is used by module authors to |
838 | build extensions and features onto the Perl 5 object system. |
e16da3e6 |
839 | |
94b19069 |
840 | =head2 Who is this module for? |
841 | |
1d68af04 |
842 | This module is specifically for anyone who has ever created or |
843 | wanted to create a module for the Class:: namespace. The tools which |
844 | this module will provide will hopefully make it easier to do more |
845 | complex things with Perl 5 classes by removing such barriers as |
846 | the need to hack the symbol tables, or understand the fine details |
847 | of method dispatch. |
94b19069 |
848 | |
bfe4d0fc |
849 | =head2 What changes do I have to make to use this module? |
850 | |
1d68af04 |
851 | This module was designed to be as unintrusive as possible. Many of |
852 | its features are accessible without B<any> change to your existsing |
853 | code at all. It is meant to be a compliment to your existing code and |
854 | not an intrusion on your code base. Unlike many other B<Class::> |
855 | modules, this module B<does not> require you subclass it, or even that |
856 | you C<use> it in within your module's package. |
bfe4d0fc |
857 | |
1d68af04 |
858 | The only features which requires additions to your code are the |
2eb717d5 |
859 | attribute handling and instance construction features, and these are |
1d68af04 |
860 | both completely optional features. The only reason for this is because |
861 | Perl 5's object system does not actually have these features built |
2eb717d5 |
862 | in. More information about this feature can be found below. |
bfe4d0fc |
863 | |
864 | =head2 A Note about Performance? |
865 | |
1d68af04 |
866 | It is a common misconception that explict MOPs are performance drains. |
867 | But this is not a universal truth at all, it is an side-effect of |
868 | specific implementations. For instance, using Java reflection is much |
869 | slower because the JVM cannot take advantage of any compiler |
870 | optimizations, and the JVM has to deal with much more runtime type |
871 | information as well. Reflection in C# is marginally better as it was |
872 | designed into the language and runtime (the CLR). In contrast, CLOS |
873 | (the Common Lisp Object System) was built to support an explicit MOP, |
874 | and so performance is tuned for it. |
875 | |
876 | This library in particular does it's absolute best to avoid putting |
877 | B<any> drain at all upon your code's performance. In fact, by itself |
878 | it does nothing to affect your existing code. So you only pay for |
2eb717d5 |
879 | what you actually use. |
bfe4d0fc |
880 | |
550d56db |
881 | =head2 About Metaclass compatibility |
882 | |
1d68af04 |
883 | This module makes sure that all metaclasses created are both upwards |
884 | and downwards compatible. The topic of metaclass compatibility is |
885 | highly esoteric and is something only encountered when doing deep and |
886 | involved metaclass hacking. There are two basic kinds of metaclass |
887 | incompatibility; upwards and downwards. |
550d56db |
888 | |
1d68af04 |
889 | Upwards metaclass compatibility means that the metaclass of a |
890 | given class is either the same as (or a subclass of) all of the |
550d56db |
891 | class's ancestors. |
892 | |
1d68af04 |
893 | Downward metaclass compatibility means that the metaclasses of a |
894 | given class's anscestors are all either the same as (or a subclass |
550d56db |
895 | of) that metaclass. |
896 | |
1d68af04 |
897 | Here is a diagram showing a set of two classes (C<A> and C<B>) and |
898 | two metaclasses (C<Meta::A> and C<Meta::B>) which have correct |
550d56db |
899 | metaclass compatibility both upwards and downwards. |
900 | |
901 | +---------+ +---------+ |
902 | | Meta::A |<----| Meta::B | <....... (instance of ) |
1d68af04 |
903 | +---------+ +---------+ <------- (inherits from) |
550d56db |
904 | ^ ^ |
905 | : : |
906 | +---------+ +---------+ |
907 | | A |<----| B | |
908 | +---------+ +---------+ |
909 | |
1d68af04 |
910 | As I said this is a highly esoteric topic and one you will only run |
911 | into if you do a lot of subclassing of B<Class::MOP::Class>. If you |
912 | are interested in why this is an issue see the paper |
913 | I<Uniform and safe metaclass composition> linked to in the |
550d56db |
914 | L<SEE ALSO> section of this document. |
915 | |
aa448b16 |
916 | =head2 Using custom metaclasses |
917 | |
1d68af04 |
918 | Always use the metaclass pragma when using a custom metaclass, this |
919 | will ensure the proper initialization order and not accidentely |
920 | create an incorrect type of metaclass for you. This is a very rare |
921 | problem, and one which can only occur if you are doing deep metaclass |
aa448b16 |
922 | programming. So in other words, don't worry about it. |
923 | |
94b19069 |
924 | =head1 PROTOCOLS |
925 | |
127d39a7 |
926 | The protocol is divided into 4 main sub-protocols: |
94b19069 |
927 | |
928 | =over 4 |
929 | |
930 | =item The Class protocol |
931 | |
1d68af04 |
932 | This provides a means of manipulating and introspecting a Perl 5 |
933 | class. It handles all of symbol table hacking for you, and provides |
94b19069 |
934 | a rich set of methods that go beyond simple package introspection. |
935 | |
552e3d24 |
936 | See L<Class::MOP::Class> for more details. |
937 | |
94b19069 |
938 | =item The Attribute protocol |
939 | |
1d68af04 |
940 | This provides a consistent represenation for an attribute of a |
941 | Perl 5 class. Since there are so many ways to create and handle |
127d39a7 |
942 | attributes in Perl 5 OO, this attempts to provide as much of a |
1d68af04 |
943 | unified approach as possible, while giving the freedom and |
94b19069 |
944 | flexibility to subclass for specialization. |
945 | |
552e3d24 |
946 | See L<Class::MOP::Attribute> for more details. |
947 | |
94b19069 |
948 | =item The Method protocol |
949 | |
1d68af04 |
950 | This provides a means of manipulating and introspecting methods in |
951 | the Perl 5 object system. As with attributes, there are many ways to |
952 | approach this topic, so we try to keep it pretty basic, while still |
94b19069 |
953 | making it possible to extend the system in many ways. |
954 | |
552e3d24 |
955 | See L<Class::MOP::Method> for more details. |
94b19069 |
956 | |
127d39a7 |
957 | =item The Instance protocol |
958 | |
959 | This provides a layer of abstraction for creating object instances. |
960 | Since the other layers use this protocol, it is relatively easy to |
961 | change the type of your instances from the default HASH ref to other |
962 | types of references. Several examples are provided in the F<examples/> |
963 | directory included in this distribution. |
964 | |
965 | See L<Class::MOP::Instance> for more details. |
966 | |
94b19069 |
967 | =back |
968 | |
be7677c7 |
969 | =head1 FUNCTIONS |
970 | |
c1d5345a |
971 | =head2 Constants |
972 | |
973 | =over 4 |
974 | |
975 | =item I<IS_RUNNING_ON_5_10> |
976 | |
977 | We set this constant depending on what version perl we are on, this |
978 | allows us to take advantage of new 5.10 features and stay backwards |
979 | compat. |
980 | |
981 | =back |
982 | |
448b6e55 |
983 | =head2 Utility functions |
984 | |
985 | =over 4 |
986 | |
987 | =item B<load_class ($class_name)> |
988 | |
1d68af04 |
989 | This will load a given C<$class_name> and if it does not have an |
448b6e55 |
990 | already initialized metaclass, then it will intialize one for it. |
127d39a7 |
991 | This function can be used in place of tricks like |
992 | C<eval "use $module"> or using C<require>. |
448b6e55 |
993 | |
994 | =item B<is_class_loaded ($class_name)> |
995 | |
1d68af04 |
996 | This will return a boolean depending on if the C<$class_name> has |
997 | been loaded. |
448b6e55 |
998 | |
1d68af04 |
999 | NOTE: This does a basic check of the symbol table to try and |
448b6e55 |
1000 | determine as best it can if the C<$class_name> is loaded, it |
1d68af04 |
1001 | is probably correct about 99% of the time. |
448b6e55 |
1002 | |
b1f5f41d |
1003 | =item B<check_package_cache_flag ($pkg)> |
e0e4674a |
1004 | |
127d39a7 |
1005 | This will return an integer that is managed by C<Class::MOP::Class> |
1006 | to determine if a module's symbol table has been altered. |
1007 | |
1008 | In Perl 5.10 or greater, this flag is package specific. However in |
1009 | versions prior to 5.10, this will use the C<PL_sub_generation> variable |
1010 | which is not package specific. |
1011 | |
e0e4674a |
1012 | =item B<get_code_info ($code)> |
1013 | |
127d39a7 |
1014 | This function returns two values, the name of the package the C<$code> |
1015 | is from and the name of the C<$code> itself. This is used by several |
1016 | elements of the MOP to detemine where a given C<$code> reference is from. |
1017 | |
4c105333 |
1018 | =item B<subname ($name, $code)> |
1019 | |
1020 | B<NOTE: DO NOT USE THIS FUNCTION, IT IS FOR INTERNAL USE ONLY!> |
1021 | |
1022 | If possible, we will load the L<Sub::Name> module and this will function |
1023 | as C<Sub::Name::subname> does, otherwise it will just return the C<$code> |
1024 | argument. |
1025 | |
448b6e55 |
1026 | =back |
1027 | |
1028 | =head2 Metaclass cache functions |
1029 | |
1d68af04 |
1030 | Class::MOP holds a cache of metaclasses, the following are functions |
1031 | (B<not methods>) which can be used to access that cache. It is not |
1032 | recommended that you mess with this, bad things could happen. But if |
be7677c7 |
1033 | you are brave and willing to risk it, go for it. |
1034 | |
1035 | =over 4 |
1036 | |
1037 | =item B<get_all_metaclasses> |
1038 | |
1d68af04 |
1039 | This will return an hash of all the metaclass instances that have |
1040 | been cached by B<Class::MOP::Class> keyed by the package name. |
b9d9fc0b |
1041 | |
be7677c7 |
1042 | =item B<get_all_metaclass_instances> |
1043 | |
1d68af04 |
1044 | This will return an array of all the metaclass instances that have |
b9d9fc0b |
1045 | been cached by B<Class::MOP::Class>. |
1046 | |
be7677c7 |
1047 | =item B<get_all_metaclass_names> |
1048 | |
1d68af04 |
1049 | This will return an array of all the metaclass names that have |
b9d9fc0b |
1050 | been cached by B<Class::MOP::Class>. |
1051 | |
be7677c7 |
1052 | =item B<get_metaclass_by_name ($name)> |
1053 | |
127d39a7 |
1054 | This will return a cached B<Class::MOP::Class> instance of nothing |
1055 | if no metaclass exist by that C<$name>. |
1056 | |
be7677c7 |
1057 | =item B<store_metaclass_by_name ($name, $meta)> |
1058 | |
127d39a7 |
1059 | This will store a metaclass in the cache at the supplied C<$key>. |
1060 | |
be7677c7 |
1061 | =item B<weaken_metaclass ($name)> |
1062 | |
127d39a7 |
1063 | In rare cases it is desireable to store a weakened reference in |
1064 | the metaclass cache. This function will weaken the reference to |
1065 | the metaclass stored in C<$name>. |
1066 | |
be7677c7 |
1067 | =item B<does_metaclass_exist ($name)> |
1068 | |
127d39a7 |
1069 | This will return true of there exists a metaclass stored in the |
1070 | C<$name> key and return false otherwise. |
1071 | |
be7677c7 |
1072 | =item B<remove_metaclass_by_name ($name)> |
1073 | |
127d39a7 |
1074 | This will remove a the metaclass stored in the C<$name> key. |
1075 | |
be7677c7 |
1076 | =back |
1077 | |
552e3d24 |
1078 | =head1 SEE ALSO |
8b978dd5 |
1079 | |
552e3d24 |
1080 | =head2 Books |
8b978dd5 |
1081 | |
1d68af04 |
1082 | There are very few books out on Meta Object Protocols and Metaclasses |
1083 | because it is such an esoteric topic. The following books are really |
1084 | the only ones I have found. If you know of any more, B<I<please>> |
a2e85e6c |
1085 | email me and let me know, I would love to hear about them. |
1086 | |
8b978dd5 |
1087 | =over 4 |
1088 | |
552e3d24 |
1089 | =item "The Art of the Meta Object Protocol" |
8b978dd5 |
1090 | |
552e3d24 |
1091 | =item "Advances in Object-Oriented Metalevel Architecture and Reflection" |
8b978dd5 |
1092 | |
b51af7f9 |
1093 | =item "Putting MetaClasses to Work" |
1094 | |
a2e85e6c |
1095 | =item "Smalltalk: The Language" |
1096 | |
94b19069 |
1097 | =back |
1098 | |
550d56db |
1099 | =head2 Papers |
1100 | |
1101 | =over 4 |
1102 | |
1103 | =item Uniform and safe metaclass composition |
1104 | |
1d68af04 |
1105 | An excellent paper by the people who brought us the original Traits paper. |
1106 | This paper is on how Traits can be used to do safe metaclass composition, |
1107 | and offers an excellent introduction section which delves into the topic of |
550d56db |
1108 | metaclass compatibility. |
1109 | |
1110 | L<http://www.iam.unibe.ch/~scg/Archive/Papers/Duca05ySafeMetaclassTrait.pdf> |
1111 | |
1112 | =item Safe Metaclass Programming |
1113 | |
1d68af04 |
1114 | This paper seems to precede the above paper, and propose a mix-in based |
1115 | approach as opposed to the Traits based approach. Both papers have similar |
1116 | information on the metaclass compatibility problem space. |
550d56db |
1117 | |
1118 | L<http://citeseer.ist.psu.edu/37617.html> |
1119 | |
1120 | =back |
1121 | |
552e3d24 |
1122 | =head2 Prior Art |
8b978dd5 |
1123 | |
1124 | =over 4 |
1125 | |
7184ca14 |
1126 | =item The Perl 6 MetaModel work in the Pugs project |
8b978dd5 |
1127 | |
1128 | =over 4 |
1129 | |
552e3d24 |
1130 | =item L<http://svn.openfoundry.org/pugs/perl5/Perl6-MetaModel> |
8b978dd5 |
1131 | |
552e3d24 |
1132 | =item L<http://svn.openfoundry.org/pugs/perl5/Perl6-ObjectSpace> |
8b978dd5 |
1133 | |
1134 | =back |
1135 | |
94b19069 |
1136 | =back |
1137 | |
1d68af04 |
1138 | =head2 Articles |
f8dfcfb7 |
1139 | |
1140 | =over 4 |
1141 | |
1d68af04 |
1142 | =item CPAN Module Review of Class::MOP |
f8dfcfb7 |
1143 | |
1144 | L<http://www.oreillynet.com/onlamp/blog/2006/06/cpan_module_review_classmop.html> |
1145 | |
1146 | =back |
1147 | |
a2e85e6c |
1148 | =head1 SIMILAR MODULES |
1149 | |
1d68af04 |
1150 | As I have said above, this module is a class-builder-builder, so it is |
1151 | not the same thing as modules like L<Class::Accessor> and |
1152 | L<Class::MethodMaker>. That being said there are very few modules on CPAN |
1153 | with similar goals to this module. The one I have found which is most |
1154 | like this module is L<Class::Meta>, although it's philosophy and the MOP it |
1155 | creates are very different from this modules. |
94b19069 |
1156 | |
a2e85e6c |
1157 | =head1 BUGS |
1158 | |
1d68af04 |
1159 | All complex software has bugs lurking in it, and this module is no |
a2e85e6c |
1160 | exception. If you find a bug please either email me, or add the bug |
1161 | to cpan-RT. |
1162 | |
1163 | =head1 ACKNOWLEDGEMENTS |
1164 | |
1165 | =over 4 |
1166 | |
b9d9fc0b |
1167 | =item Rob Kinyon |
a2e85e6c |
1168 | |
1d68af04 |
1169 | Thanks to Rob for actually getting the development of this module kick-started. |
a2e85e6c |
1170 | |
1171 | =back |
1172 | |
1a09d9cc |
1173 | =head1 AUTHORS |
94b19069 |
1174 | |
a2e85e6c |
1175 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
552e3d24 |
1176 | |
9c8cda90 |
1177 | B<with contributions from:> |
1178 | |
1179 | Brandon (blblack) Black |
1180 | |
1181 | Guillermo (groditi) Roditi |
1182 | |
9195ddff |
1183 | Matt (mst) Trout |
1184 | |
9c8cda90 |
1185 | Rob (robkinyon) Kinyon |
1186 | |
1187 | Yuval (nothingmuch) Kogman |
1a09d9cc |
1188 | |
f430cfa4 |
1189 | Scott (konobi) McWhirter |
1190 | |
94b19069 |
1191 | =head1 COPYRIGHT AND LICENSE |
1192 | |
69e3ab0a |
1193 | Copyright 2006-2008 by Infinity Interactive, Inc. |
94b19069 |
1194 | |
1195 | L<http://www.iinteractive.com> |
1196 | |
1197 | This library is free software; you can redistribute it and/or modify |
1d68af04 |
1198 | it under the same terms as Perl itself. |
94b19069 |
1199 | |
1200 | =cut |