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 | |
a023763e |
20 | our $VERSION = '0.61'; |
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 | |
1d68af04 |
134 | # see if this is already |
448b6e55 |
135 | # loaded in the symbol table |
136 | return 1 if is_class_loaded($class); |
137 | # otherwise require it ... |
138 | my $file = $class . '.pm'; |
139 | $file =~ s{::}{/}g; |
140 | eval { CORE::require($file) }; |
141 | confess "Could not load class ($class) because : $@" if $@; |
142 | unless (does_metaclass_exist($class)) { |
143 | eval { Class::MOP::Class->initialize($class) }; |
1d68af04 |
144 | confess "Could not initialize class ($class) because : $@" if $@; |
448b6e55 |
145 | } |
146 | 1; # return true if it worked |
147 | } |
148 | |
149 | sub is_class_loaded { |
c1d5345a |
150 | my $class = shift; |
26fcef27 |
151 | |
152 | return 0 if ref($class) || !defined($class) || !length($class); |
153 | |
154 | # walk the symbol table tree to avoid autovififying |
155 | # \*{${main::}{"Foo::"}} == \*main::Foo:: |
156 | |
157 | my $pack = \*::; |
158 | foreach my $part (split('::', $class)) { |
159 | return 0 unless exists ${$$pack}{"${part}::"}; |
160 | $pack = \*{${$$pack}{"${part}::"}}; |
c1d5345a |
161 | } |
26fcef27 |
162 | |
163 | # check for $VERSION or @ISA |
164 | return 1 if exists ${$$pack}{VERSION} |
165 | && defined *{${$$pack}{VERSION}}{SCALAR}; |
166 | return 1 if exists ${$$pack}{ISA} |
167 | && defined *{${$$pack}{ISA}}{ARRAY}; |
168 | |
169 | # check for any method |
170 | foreach ( keys %{$$pack} ) { |
171 | next if substr($_, -2, 2) eq '::'; |
172 | return 1 if defined *{${$$pack}{$_}}{CODE}; |
173 | } |
174 | |
175 | # fail |
c1d5345a |
176 | return 0; |
448b6e55 |
177 | } |
178 | |
179 | |
aa448b16 |
180 | ## ---------------------------------------------------------------------------- |
181 | ## Setting up our environment ... |
182 | ## ---------------------------------------------------------------------------- |
1d68af04 |
183 | ## Class::MOP needs to have a few things in the global perl environment so |
aa448b16 |
184 | ## that it can operate effectively. Those things are done here. |
185 | ## ---------------------------------------------------------------------------- |
186 | |
3bf7644b |
187 | # ... nothing yet actually ;) |
8b978dd5 |
188 | |
b51af7f9 |
189 | ## ---------------------------------------------------------------------------- |
1d68af04 |
190 | ## Bootstrapping |
b51af7f9 |
191 | ## ---------------------------------------------------------------------------- |
1d68af04 |
192 | ## The code below here is to bootstrap our MOP with itself. This is also |
b51af7f9 |
193 | ## sometimes called "tying the knot". By doing this, we make it much easier |
194 | ## to extend the MOP through subclassing and such since now you can use the |
1d68af04 |
195 | ## MOP itself to extend itself. |
196 | ## |
b51af7f9 |
197 | ## Yes, I know, thats weird and insane, but it's a good thing, trust me :) |
1d68af04 |
198 | ## ---------------------------------------------------------------------------- |
727919c5 |
199 | |
1d68af04 |
200 | # We need to add in the meta-attributes here so that |
201 | # any subclass of Class::MOP::* will be able to |
727919c5 |
202 | # inherit them using &construct_instance |
203 | |
f0480c45 |
204 | ## -------------------------------------------------------- |
6d5355c3 |
205 | ## Class::MOP::Package |
727919c5 |
206 | |
6d5355c3 |
207 | Class::MOP::Package->meta->add_attribute( |
c23184fc |
208 | Class::MOP::Attribute->new('$!package' => ( |
b880e0de |
209 | reader => { |
1d68af04 |
210 | # NOTE: we need to do this in order |
211 | # for the instance meta-object to |
b880e0de |
212 | # not fall into meta-circular death |
1d68af04 |
213 | # |
ce2ae40f |
214 | # we just alias the original method |
1d68af04 |
215 | # rather than re-produce it here |
ce2ae40f |
216 | 'name' => \&Class::MOP::Package::name |
b880e0de |
217 | }, |
c23184fc |
218 | init_arg => 'package', |
727919c5 |
219 | )) |
220 | ); |
221 | |
a5e51f0b |
222 | Class::MOP::Package->meta->add_attribute( |
c23184fc |
223 | Class::MOP::Attribute->new('%!namespace' => ( |
a5e51f0b |
224 | reader => { |
56dcfc1a |
225 | # NOTE: |
ce2ae40f |
226 | # we just alias the original method |
227 | # rather than re-produce it here |
228 | 'namespace' => \&Class::MOP::Package::namespace |
a5e51f0b |
229 | }, |
2e877f58 |
230 | init_arg => undef, |
c4260b45 |
231 | default => sub { \undef } |
a5e51f0b |
232 | )) |
233 | ); |
234 | |
9d6dce77 |
235 | # NOTE: |
236 | # use the metaclass to construct the meta-package |
237 | # which is a superclass of the metaclass itself :P |
238 | Class::MOP::Package->meta->add_method('initialize' => sub { |
239 | my $class = shift; |
240 | my $package_name = shift; |
1d68af04 |
241 | $class->meta->new_object('package' => $package_name, @_); |
9d6dce77 |
242 | }); |
243 | |
f0480c45 |
244 | ## -------------------------------------------------------- |
245 | ## Class::MOP::Module |
246 | |
247 | # NOTE: |
1d68af04 |
248 | # yeah this is kind of stretching things a bit, |
f0480c45 |
249 | # but truthfully the version should be an attribute |
1d68af04 |
250 | # of the Module, the weirdness comes from having to |
251 | # stick to Perl 5 convention and store it in the |
252 | # $VERSION package variable. Basically if you just |
253 | # squint at it, it will look how you want it to look. |
f0480c45 |
254 | # Either as a package variable, or as a attribute of |
255 | # the metaclass, isn't abstraction great :) |
256 | |
257 | Class::MOP::Module->meta->add_attribute( |
c23184fc |
258 | Class::MOP::Attribute->new('$!version' => ( |
f0480c45 |
259 | reader => { |
ce2ae40f |
260 | # NOTE: |
261 | # we just alias the original method |
1d68af04 |
262 | # rather than re-produce it here |
ce2ae40f |
263 | 'version' => \&Class::MOP::Module::version |
f0480c45 |
264 | }, |
2e877f58 |
265 | init_arg => undef, |
c4260b45 |
266 | default => sub { \undef } |
f0480c45 |
267 | )) |
268 | ); |
269 | |
270 | # NOTE: |
1d68af04 |
271 | # By following the same conventions as version here, |
272 | # we are opening up the possibility that people can |
273 | # use the $AUTHORITY in non-Class::MOP modules as |
274 | # well. |
f0480c45 |
275 | |
276 | Class::MOP::Module->meta->add_attribute( |
c23184fc |
277 | Class::MOP::Attribute->new('$!authority' => ( |
f0480c45 |
278 | reader => { |
ce2ae40f |
279 | # NOTE: |
280 | # we just alias the original method |
1d68af04 |
281 | # rather than re-produce it here |
ce2ae40f |
282 | 'authority' => \&Class::MOP::Module::authority |
1d68af04 |
283 | }, |
2e877f58 |
284 | init_arg => undef, |
c4260b45 |
285 | default => sub { \undef } |
f0480c45 |
286 | )) |
287 | ); |
288 | |
289 | ## -------------------------------------------------------- |
6d5355c3 |
290 | ## Class::MOP::Class |
291 | |
727919c5 |
292 | Class::MOP::Class->meta->add_attribute( |
c23184fc |
293 | Class::MOP::Attribute->new('%!attributes' => ( |
f7259199 |
294 | reader => { |
1d68af04 |
295 | # NOTE: we need to do this in order |
296 | # for the instance meta-object to |
297 | # not fall into meta-circular death |
298 | # |
ce2ae40f |
299 | # we just alias the original method |
1d68af04 |
300 | # rather than re-produce it here |
ce2ae40f |
301 | 'get_attribute_map' => \&Class::MOP::Class::get_attribute_map |
f7259199 |
302 | }, |
c23184fc |
303 | init_arg => 'attributes', |
727919c5 |
304 | default => sub { {} } |
305 | )) |
306 | ); |
307 | |
351bd7d4 |
308 | Class::MOP::Class->meta->add_attribute( |
c23184fc |
309 | Class::MOP::Attribute->new('%!methods' => ( |
310 | init_arg => 'methods', |
1d68af04 |
311 | reader => { |
ce2ae40f |
312 | # NOTE: |
313 | # we just alias the original method |
1d68af04 |
314 | # rather than re-produce it here |
ce2ae40f |
315 | 'get_method_map' => \&Class::MOP::Class::get_method_map |
92330ee2 |
316 | }, |
7855ddba |
317 | default => sub { {} } |
c4260b45 |
318 | )) |
319 | ); |
320 | |
321 | Class::MOP::Class->meta->add_attribute( |
c23184fc |
322 | Class::MOP::Attribute->new('@!superclasses' => ( |
323 | accessor => { |
324 | # NOTE: |
325 | # we just alias the original method |
1d68af04 |
326 | # rather than re-produce it here |
c23184fc |
327 | 'superclasses' => \&Class::MOP::Class::superclasses |
328 | }, |
2e877f58 |
329 | init_arg => undef, |
c23184fc |
330 | default => sub { \undef } |
331 | )) |
332 | ); |
333 | |
334 | Class::MOP::Class->meta->add_attribute( |
335 | Class::MOP::Attribute->new('$!attribute_metaclass' => ( |
1d68af04 |
336 | reader => { |
6d2118a4 |
337 | # NOTE: |
338 | # we just alias the original method |
1d68af04 |
339 | # rather than re-produce it here |
6d2118a4 |
340 | 'attribute_metaclass' => \&Class::MOP::Class::attribute_metaclass |
1d68af04 |
341 | }, |
c23184fc |
342 | init_arg => 'attribute_metaclass', |
351bd7d4 |
343 | default => 'Class::MOP::Attribute', |
344 | )) |
345 | ); |
346 | |
347 | Class::MOP::Class->meta->add_attribute( |
c23184fc |
348 | Class::MOP::Attribute->new('$!method_metaclass' => ( |
1d68af04 |
349 | reader => { |
6d2118a4 |
350 | # NOTE: |
351 | # we just alias the original method |
1d68af04 |
352 | # rather than re-produce it here |
6d2118a4 |
353 | 'method_metaclass' => \&Class::MOP::Class::method_metaclass |
354 | }, |
c23184fc |
355 | init_arg => 'method_metaclass', |
1d68af04 |
356 | default => 'Class::MOP::Method', |
351bd7d4 |
357 | )) |
358 | ); |
359 | |
2bab2be6 |
360 | Class::MOP::Class->meta->add_attribute( |
c23184fc |
361 | Class::MOP::Attribute->new('$!instance_metaclass' => ( |
b880e0de |
362 | reader => { |
1d68af04 |
363 | # NOTE: we need to do this in order |
364 | # for the instance meta-object to |
365 | # not fall into meta-circular death |
366 | # |
ce2ae40f |
367 | # we just alias the original method |
1d68af04 |
368 | # rather than re-produce it here |
ce2ae40f |
369 | 'instance_metaclass' => \&Class::MOP::Class::instance_metaclass |
b880e0de |
370 | }, |
c23184fc |
371 | init_arg => 'instance_metaclass', |
1d68af04 |
372 | default => 'Class::MOP::Instance', |
2bab2be6 |
373 | )) |
374 | ); |
375 | |
9d6dce77 |
376 | # NOTE: |
1d68af04 |
377 | # we don't actually need to tie the knot with |
378 | # Class::MOP::Class here, it is actually handled |
379 | # within Class::MOP::Class itself in the |
380 | # construct_class_instance method. |
9d6dce77 |
381 | |
f0480c45 |
382 | ## -------------------------------------------------------- |
727919c5 |
383 | ## Class::MOP::Attribute |
384 | |
7b31baf4 |
385 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
386 | Class::MOP::Attribute->new('$!name' => ( |
387 | init_arg => 'name', |
388 | reader => { |
1d68af04 |
389 | # NOTE: we need to do this in order |
390 | # for the instance meta-object to |
391 | # not fall into meta-circular death |
392 | # |
ce2ae40f |
393 | # we just alias the original method |
1d68af04 |
394 | # rather than re-produce it here |
ce2ae40f |
395 | 'name' => \&Class::MOP::Attribute::name |
b880e0de |
396 | } |
7b31baf4 |
397 | )) |
398 | ); |
399 | |
400 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
401 | Class::MOP::Attribute->new('$!associated_class' => ( |
402 | init_arg => 'associated_class', |
403 | reader => { |
1d68af04 |
404 | # NOTE: we need to do this in order |
405 | # for the instance meta-object to |
406 | # not fall into meta-circular death |
407 | # |
ce2ae40f |
408 | # we just alias the original method |
1d68af04 |
409 | # rather than re-produce it here |
ce2ae40f |
410 | 'associated_class' => \&Class::MOP::Attribute::associated_class |
b880e0de |
411 | } |
7b31baf4 |
412 | )) |
413 | ); |
414 | |
415 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
416 | Class::MOP::Attribute->new('$!accessor' => ( |
417 | init_arg => 'accessor', |
6d2118a4 |
418 | reader => { 'accessor' => \&Class::MOP::Attribute::accessor }, |
419 | predicate => { 'has_accessor' => \&Class::MOP::Attribute::has_accessor }, |
7b31baf4 |
420 | )) |
421 | ); |
422 | |
423 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
424 | Class::MOP::Attribute->new('$!reader' => ( |
425 | init_arg => 'reader', |
6d2118a4 |
426 | reader => { 'reader' => \&Class::MOP::Attribute::reader }, |
427 | predicate => { 'has_reader' => \&Class::MOP::Attribute::has_reader }, |
7b31baf4 |
428 | )) |
429 | ); |
430 | |
431 | Class::MOP::Attribute->meta->add_attribute( |
0ab65f99 |
432 | Class::MOP::Attribute->new('$!initializer' => ( |
433 | init_arg => 'initializer', |
8ee74136 |
434 | reader => { 'initializer' => \&Class::MOP::Attribute::initializer }, |
435 | predicate => { 'has_initializer' => \&Class::MOP::Attribute::has_initializer }, |
0ab65f99 |
436 | )) |
437 | ); |
438 | |
439 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
440 | Class::MOP::Attribute->new('$!writer' => ( |
441 | init_arg => 'writer', |
6d2118a4 |
442 | reader => { 'writer' => \&Class::MOP::Attribute::writer }, |
443 | predicate => { 'has_writer' => \&Class::MOP::Attribute::has_writer }, |
7b31baf4 |
444 | )) |
445 | ); |
446 | |
447 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
448 | Class::MOP::Attribute->new('$!predicate' => ( |
449 | init_arg => 'predicate', |
6d2118a4 |
450 | reader => { 'predicate' => \&Class::MOP::Attribute::predicate }, |
451 | predicate => { 'has_predicate' => \&Class::MOP::Attribute::has_predicate }, |
7b31baf4 |
452 | )) |
453 | ); |
454 | |
455 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
456 | Class::MOP::Attribute->new('$!clearer' => ( |
457 | init_arg => 'clearer', |
6d2118a4 |
458 | reader => { 'clearer' => \&Class::MOP::Attribute::clearer }, |
459 | predicate => { 'has_clearer' => \&Class::MOP::Attribute::has_clearer }, |
7d28758b |
460 | )) |
461 | ); |
462 | |
463 | Class::MOP::Attribute->meta->add_attribute( |
1d68af04 |
464 | Class::MOP::Attribute->new('$!builder' => ( |
465 | init_arg => 'builder', |
466 | reader => { 'builder' => \&Class::MOP::Attribute::builder }, |
467 | predicate => { 'has_builder' => \&Class::MOP::Attribute::has_builder }, |
468 | )) |
469 | ); |
470 | |
471 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
472 | Class::MOP::Attribute->new('$!init_arg' => ( |
473 | init_arg => 'init_arg', |
6d2118a4 |
474 | reader => { 'init_arg' => \&Class::MOP::Attribute::init_arg }, |
475 | predicate => { 'has_init_arg' => \&Class::MOP::Attribute::has_init_arg }, |
7b31baf4 |
476 | )) |
477 | ); |
478 | |
479 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
480 | Class::MOP::Attribute->new('$!default' => ( |
481 | init_arg => 'default', |
7b31baf4 |
482 | # default has a custom 'reader' method ... |
1d68af04 |
483 | predicate => { 'has_default' => \&Class::MOP::Attribute::has_default }, |
7b31baf4 |
484 | )) |
485 | ); |
486 | |
3545c727 |
487 | Class::MOP::Attribute->meta->add_attribute( |
c23184fc |
488 | Class::MOP::Attribute->new('@!associated_methods' => ( |
489 | init_arg => 'associated_methods', |
490 | reader => { 'associated_methods' => \&Class::MOP::Attribute::associated_methods }, |
1d68af04 |
491 | default => sub { [] } |
3545c727 |
492 | )) |
493 | ); |
727919c5 |
494 | |
495 | # NOTE: (meta-circularity) |
496 | # This should be one of the last things done |
497 | # it will "tie the knot" with Class::MOP::Attribute |
1d68af04 |
498 | # so that it uses the attributes meta-objects |
499 | # to construct itself. |
727919c5 |
500 | Class::MOP::Attribute->meta->add_method('new' => sub { |
501 | my $class = shift; |
502 | my $name = shift; |
1d68af04 |
503 | my %options = @_; |
504 | |
727919c5 |
505 | (defined $name && $name) |
506 | || confess "You must provide a name for the attribute"; |
1d68af04 |
507 | $options{init_arg} = $name |
5659d76e |
508 | if not exists $options{init_arg}; |
1d68af04 |
509 | |
510 | if(exists $options{builder}){ |
511 | confess("builder must be a defined scalar value which is a method name") |
512 | if ref $options{builder} || !(defined $options{builder}); |
513 | confess("Setting both default and builder is not allowed.") |
514 | if exists $options{default}; |
8fe581e5 |
515 | } else { |
516 | (Class::MOP::Attribute::is_default_a_coderef(\%options)) |
517 | || confess("References are not allowed as default values, you must ". |
3c0a8087 |
518 | "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])") |
8fe581e5 |
519 | if exists $options{default} && ref $options{default}; |
1d68af04 |
520 | } |
5659d76e |
521 | # return the new object |
522 | $class->meta->new_object(name => $name, %options); |
523 | }); |
524 | |
525 | Class::MOP::Attribute->meta->add_method('clone' => sub { |
a740253a |
526 | my $self = shift; |
1d68af04 |
527 | $self->meta->clone_object($self, @_); |
727919c5 |
528 | }); |
529 | |
f0480c45 |
530 | ## -------------------------------------------------------- |
b6164407 |
531 | ## Class::MOP::Method |
532 | |
533 | Class::MOP::Method->meta->add_attribute( |
c23184fc |
534 | Class::MOP::Attribute->new('&!body' => ( |
535 | init_arg => 'body', |
536 | reader => { 'body' => \&Class::MOP::Method::body }, |
b6164407 |
537 | )) |
538 | ); |
539 | |
4c105333 |
540 | Class::MOP::Method->meta->add_attribute( |
541 | Class::MOP::Attribute->new('$!package_name' => ( |
542 | init_arg => 'package_name', |
543 | reader => { 'package_name' => \&Class::MOP::Method::package_name }, |
544 | )) |
545 | ); |
546 | |
547 | Class::MOP::Method->meta->add_attribute( |
548 | Class::MOP::Attribute->new('$!name' => ( |
549 | init_arg => 'name', |
550 | reader => { 'name' => \&Class::MOP::Method::name }, |
551 | )) |
552 | ); |
553 | |
554 | Class::MOP::Method->meta->add_method('wrap' => sub { |
555 | my $class = shift; |
556 | my $code = shift; |
557 | my %options = @_; |
558 | |
9b522fc4 |
559 | ('CODE' eq ref($code)) |
4c105333 |
560 | || confess "You must supply a CODE reference to bless, not (" . ($code || 'undef') . ")"; |
561 | |
b38f3848 |
562 | ($options{package_name} && $options{name}) |
563 | || confess "You must supply the package_name and name parameters"; |
564 | |
4c105333 |
565 | # return the new object |
566 | $class->meta->new_object(body => $code, %options); |
567 | }); |
568 | |
569 | Class::MOP::Method->meta->add_method('clone' => sub { |
570 | my $self = shift; |
571 | $self->meta->clone_object($self, @_); |
572 | }); |
573 | |
b6164407 |
574 | ## -------------------------------------------------------- |
575 | ## Class::MOP::Method::Wrapped |
576 | |
577 | # NOTE: |
1d68af04 |
578 | # the way this item is initialized, this |
579 | # really does not follow the standard |
580 | # practices of attributes, but we put |
b6164407 |
581 | # it here for completeness |
582 | Class::MOP::Method::Wrapped->meta->add_attribute( |
c23184fc |
583 | Class::MOP::Attribute->new('%!modifier_table') |
b6164407 |
584 | ); |
585 | |
586 | ## -------------------------------------------------------- |
565f0cbb |
587 | ## Class::MOP::Method::Generated |
588 | |
589 | Class::MOP::Method::Generated->meta->add_attribute( |
590 | Class::MOP::Attribute->new('$!is_inline' => ( |
591 | init_arg => 'is_inline', |
592 | reader => { 'is_inline' => \&Class::MOP::Method::Generated::is_inline }, |
4c105333 |
593 | default => 0, |
1d68af04 |
594 | )) |
565f0cbb |
595 | ); |
596 | |
4c105333 |
597 | Class::MOP::Method::Generated->meta->add_method('new' => sub { |
598 | my ($class, %options) = @_; |
b38f3848 |
599 | ($options{package_name} && $options{name}) |
600 | || confess "You must supply the package_name and name parameters"; |
4c105333 |
601 | my $self = $class->meta->new_object(%options); |
602 | $self->initialize_body; |
603 | $self; |
604 | }); |
605 | |
565f0cbb |
606 | ## -------------------------------------------------------- |
d90b42a6 |
607 | ## Class::MOP::Method::Accessor |
608 | |
609 | Class::MOP::Method::Accessor->meta->add_attribute( |
c23184fc |
610 | Class::MOP::Attribute->new('$!attribute' => ( |
611 | init_arg => 'attribute', |
1d68af04 |
612 | reader => { |
613 | 'associated_attribute' => \&Class::MOP::Method::Accessor::associated_attribute |
d90b42a6 |
614 | }, |
1d68af04 |
615 | )) |
d90b42a6 |
616 | ); |
617 | |
618 | Class::MOP::Method::Accessor->meta->add_attribute( |
c23184fc |
619 | Class::MOP::Attribute->new('$!accessor_type' => ( |
620 | init_arg => 'accessor_type', |
621 | reader => { 'accessor_type' => \&Class::MOP::Method::Accessor::accessor_type }, |
1d68af04 |
622 | )) |
d90b42a6 |
623 | ); |
624 | |
4c105333 |
625 | Class::MOP::Method::Accessor->meta->add_method('new' => sub { |
626 | my $class = shift; |
627 | my %options = @_; |
628 | |
629 | (exists $options{attribute}) |
630 | || confess "You must supply an attribute to construct with"; |
631 | |
632 | (exists $options{accessor_type}) |
633 | || confess "You must supply an accessor_type to construct with"; |
634 | |
635 | (Scalar::Util::blessed($options{attribute}) && $options{attribute}->isa('Class::MOP::Attribute')) |
636 | || confess "You must supply an attribute which is a 'Class::MOP::Attribute' instance"; |
637 | |
b38f3848 |
638 | ($options{package_name} && $options{name}) |
639 | || confess "You must supply the package_name and name parameters"; |
640 | |
4c105333 |
641 | # return the new object |
642 | my $self = $class->meta->new_object(%options); |
643 | |
644 | # we don't want this creating |
645 | # a cycle in the code, if not |
646 | # needed |
647 | Scalar::Util::weaken($self->{'$!attribute'}); |
648 | |
649 | $self->initialize_body; |
650 | |
651 | $self; |
652 | }); |
653 | |
d90b42a6 |
654 | |
655 | ## -------------------------------------------------------- |
656 | ## Class::MOP::Method::Constructor |
657 | |
658 | Class::MOP::Method::Constructor->meta->add_attribute( |
c23184fc |
659 | Class::MOP::Attribute->new('%!options' => ( |
660 | init_arg => 'options', |
1d68af04 |
661 | reader => { |
662 | 'options' => \&Class::MOP::Method::Constructor::options |
d90b42a6 |
663 | }, |
4c105333 |
664 | default => sub { +{} } |
1d68af04 |
665 | )) |
d90b42a6 |
666 | ); |
667 | |
668 | Class::MOP::Method::Constructor->meta->add_attribute( |
c23184fc |
669 | Class::MOP::Attribute->new('$!associated_metaclass' => ( |
670 | init_arg => 'metaclass', |
1d68af04 |
671 | reader => { |
672 | 'associated_metaclass' => \&Class::MOP::Method::Constructor::associated_metaclass |
673 | }, |
674 | )) |
d90b42a6 |
675 | ); |
676 | |
4c105333 |
677 | Class::MOP::Method::Constructor->meta->add_method('new' => sub { |
678 | my $class = shift; |
679 | my %options = @_; |
680 | |
681 | (Scalar::Util::blessed $options{metaclass} && $options{metaclass}->isa('Class::MOP::Class')) |
682 | || confess "You must pass a metaclass instance if you want to inline" |
683 | if $options{is_inline}; |
684 | |
b38f3848 |
685 | ($options{package_name} && $options{name}) |
686 | || confess "You must supply the package_name and name parameters"; |
687 | |
4c105333 |
688 | # return the new object |
689 | my $self = $class->meta->new_object(%options); |
690 | |
691 | # we don't want this creating |
692 | # a cycle in the code, if not |
693 | # needed |
694 | Scalar::Util::weaken($self->{'$!associated_metaclass'}); |
695 | |
696 | $self->initialize_body; |
697 | |
698 | $self; |
699 | }); |
700 | |
d90b42a6 |
701 | ## -------------------------------------------------------- |
86482605 |
702 | ## Class::MOP::Instance |
703 | |
704 | # NOTE: |
1d68af04 |
705 | # these don't yet do much of anything, but are just |
86482605 |
706 | # included for completeness |
707 | |
708 | Class::MOP::Instance->meta->add_attribute( |
c23184fc |
709 | Class::MOP::Attribute->new('$!meta') |
86482605 |
710 | ); |
711 | |
712 | Class::MOP::Instance->meta->add_attribute( |
c23184fc |
713 | Class::MOP::Attribute->new('@!slots') |
86482605 |
714 | ); |
715 | |
716 | ## -------------------------------------------------------- |
f0480c45 |
717 | ## Now close all the Class::MOP::* classes |
4d47b77f |
718 | |
0b9372a2 |
719 | # NOTE: |
1d68af04 |
720 | # we don't need to inline the |
721 | # constructors or the accessors |
722 | # this only lengthens the compile |
723 | # time of the MOP, and gives us |
0b9372a2 |
724 | # no actual benefits. |
725 | |
726 | $_->meta->make_immutable( |
727 | inline_constructor => 0, |
728 | inline_accessors => 0, |
729 | ) for qw/ |
1d68af04 |
730 | Class::MOP::Package |
731 | Class::MOP::Module |
732 | Class::MOP::Class |
733 | |
0b9372a2 |
734 | Class::MOP::Attribute |
1d68af04 |
735 | Class::MOP::Method |
736 | Class::MOP::Instance |
737 | |
738 | Class::MOP::Object |
0b9372a2 |
739 | |
565f0cbb |
740 | Class::MOP::Method::Generated |
1d68af04 |
741 | |
ba38bf08 |
742 | Class::MOP::Method::Accessor |
1d68af04 |
743 | Class::MOP::Method::Constructor |
744 | Class::MOP::Method::Wrapped |
0b9372a2 |
745 | /; |
b6164407 |
746 | |
94b19069 |
747 | 1; |
748 | |
749 | __END__ |
750 | |
751 | =pod |
752 | |
1d68af04 |
753 | =head1 NAME |
94b19069 |
754 | |
755 | Class::MOP - A Meta Object Protocol for Perl 5 |
756 | |
94b19069 |
757 | =head1 DESCRIPTON |
758 | |
127d39a7 |
759 | This module is a fully functioning meta object protocol for the |
1d68af04 |
760 | Perl 5 object system. It makes no attempt to change the behavior or |
761 | characteristics of the Perl 5 object system, only to create a |
27e31eaf |
762 | protocol for its manipulation and introspection. |
94b19069 |
763 | |
1d68af04 |
764 | That said, it does attempt to create the tools for building a rich |
765 | set of extensions to the Perl 5 object system. Every attempt has been |
766 | made for these tools to keep to the spirit of the Perl 5 object |
94b19069 |
767 | system that we all know and love. |
768 | |
1d68af04 |
769 | This documentation is admittedly sparse on details, as time permits |
770 | I will try to improve them. For now, I suggest looking at the items |
771 | listed in the L<SEE ALSO> section for more information. In particular |
772 | the book "The Art of the Meta Object Protocol" was very influential |
40483095 |
773 | in the development of this system. |
774 | |
bfe4d0fc |
775 | =head2 What is a Meta Object Protocol? |
776 | |
1d68af04 |
777 | A meta object protocol is an API to an object system. |
bfe4d0fc |
778 | |
1d68af04 |
779 | To be more specific, it is a set of abstractions of the components of |
780 | an object system (typically things like; classes, object, methods, |
781 | object attributes, etc.). These abstractions can then be used to both |
bfe4d0fc |
782 | inspect and manipulate the object system which they describe. |
783 | |
1d68af04 |
784 | It can be said that there are two MOPs for any object system; the |
785 | implicit MOP, and the explicit MOP. The implicit MOP handles things |
786 | like method dispatch or inheritance, which happen automatically as |
787 | part of how the object system works. The explicit MOP typically |
788 | handles the introspection/reflection features of the object system. |
789 | All object systems have implicit MOPs, without one, they would not |
790 | work. Explict MOPs however as less common, and depending on the |
791 | language can vary from restrictive (Reflection in Java or C#) to |
792 | wide open (CLOS is a perfect example). |
bfe4d0fc |
793 | |
e16da3e6 |
794 | =head2 Yet Another Class Builder!! Why? |
795 | |
1d68af04 |
796 | This is B<not> a class builder so much as it is a I<class builder |
797 | B<builder>>. My intent is that an end user does not use this module |
798 | directly, but instead this module is used by module authors to |
799 | build extensions and features onto the Perl 5 object system. |
e16da3e6 |
800 | |
94b19069 |
801 | =head2 Who is this module for? |
802 | |
1d68af04 |
803 | This module is specifically for anyone who has ever created or |
804 | wanted to create a module for the Class:: namespace. The tools which |
805 | this module will provide will hopefully make it easier to do more |
806 | complex things with Perl 5 classes by removing such barriers as |
807 | the need to hack the symbol tables, or understand the fine details |
808 | of method dispatch. |
94b19069 |
809 | |
bfe4d0fc |
810 | =head2 What changes do I have to make to use this module? |
811 | |
1d68af04 |
812 | This module was designed to be as unintrusive as possible. Many of |
813 | its features are accessible without B<any> change to your existsing |
814 | code at all. It is meant to be a compliment to your existing code and |
815 | not an intrusion on your code base. Unlike many other B<Class::> |
816 | modules, this module B<does not> require you subclass it, or even that |
817 | you C<use> it in within your module's package. |
bfe4d0fc |
818 | |
1d68af04 |
819 | The only features which requires additions to your code are the |
2eb717d5 |
820 | attribute handling and instance construction features, and these are |
1d68af04 |
821 | both completely optional features. The only reason for this is because |
822 | Perl 5's object system does not actually have these features built |
2eb717d5 |
823 | in. More information about this feature can be found below. |
bfe4d0fc |
824 | |
825 | =head2 A Note about Performance? |
826 | |
1d68af04 |
827 | It is a common misconception that explict MOPs are performance drains. |
828 | But this is not a universal truth at all, it is an side-effect of |
829 | specific implementations. For instance, using Java reflection is much |
830 | slower because the JVM cannot take advantage of any compiler |
831 | optimizations, and the JVM has to deal with much more runtime type |
832 | information as well. Reflection in C# is marginally better as it was |
833 | designed into the language and runtime (the CLR). In contrast, CLOS |
834 | (the Common Lisp Object System) was built to support an explicit MOP, |
835 | and so performance is tuned for it. |
836 | |
837 | This library in particular does it's absolute best to avoid putting |
838 | B<any> drain at all upon your code's performance. In fact, by itself |
839 | it does nothing to affect your existing code. So you only pay for |
2eb717d5 |
840 | what you actually use. |
bfe4d0fc |
841 | |
550d56db |
842 | =head2 About Metaclass compatibility |
843 | |
1d68af04 |
844 | This module makes sure that all metaclasses created are both upwards |
845 | and downwards compatible. The topic of metaclass compatibility is |
846 | highly esoteric and is something only encountered when doing deep and |
847 | involved metaclass hacking. There are two basic kinds of metaclass |
848 | incompatibility; upwards and downwards. |
550d56db |
849 | |
1d68af04 |
850 | Upwards metaclass compatibility means that the metaclass of a |
851 | given class is either the same as (or a subclass of) all of the |
550d56db |
852 | class's ancestors. |
853 | |
1d68af04 |
854 | Downward metaclass compatibility means that the metaclasses of a |
855 | given class's anscestors are all either the same as (or a subclass |
550d56db |
856 | of) that metaclass. |
857 | |
1d68af04 |
858 | Here is a diagram showing a set of two classes (C<A> and C<B>) and |
859 | two metaclasses (C<Meta::A> and C<Meta::B>) which have correct |
550d56db |
860 | metaclass compatibility both upwards and downwards. |
861 | |
862 | +---------+ +---------+ |
863 | | Meta::A |<----| Meta::B | <....... (instance of ) |
1d68af04 |
864 | +---------+ +---------+ <------- (inherits from) |
550d56db |
865 | ^ ^ |
866 | : : |
867 | +---------+ +---------+ |
868 | | A |<----| B | |
869 | +---------+ +---------+ |
870 | |
1d68af04 |
871 | As I said this is a highly esoteric topic and one you will only run |
872 | into if you do a lot of subclassing of B<Class::MOP::Class>. If you |
873 | are interested in why this is an issue see the paper |
874 | I<Uniform and safe metaclass composition> linked to in the |
550d56db |
875 | L<SEE ALSO> section of this document. |
876 | |
aa448b16 |
877 | =head2 Using custom metaclasses |
878 | |
1d68af04 |
879 | Always use the metaclass pragma when using a custom metaclass, this |
880 | will ensure the proper initialization order and not accidentely |
881 | create an incorrect type of metaclass for you. This is a very rare |
882 | problem, and one which can only occur if you are doing deep metaclass |
aa448b16 |
883 | programming. So in other words, don't worry about it. |
884 | |
94b19069 |
885 | =head1 PROTOCOLS |
886 | |
127d39a7 |
887 | The protocol is divided into 4 main sub-protocols: |
94b19069 |
888 | |
889 | =over 4 |
890 | |
891 | =item The Class protocol |
892 | |
1d68af04 |
893 | This provides a means of manipulating and introspecting a Perl 5 |
894 | class. It handles all of symbol table hacking for you, and provides |
94b19069 |
895 | a rich set of methods that go beyond simple package introspection. |
896 | |
552e3d24 |
897 | See L<Class::MOP::Class> for more details. |
898 | |
94b19069 |
899 | =item The Attribute protocol |
900 | |
1d68af04 |
901 | This provides a consistent represenation for an attribute of a |
902 | Perl 5 class. Since there are so many ways to create and handle |
127d39a7 |
903 | attributes in Perl 5 OO, this attempts to provide as much of a |
1d68af04 |
904 | unified approach as possible, while giving the freedom and |
94b19069 |
905 | flexibility to subclass for specialization. |
906 | |
552e3d24 |
907 | See L<Class::MOP::Attribute> for more details. |
908 | |
94b19069 |
909 | =item The Method protocol |
910 | |
1d68af04 |
911 | This provides a means of manipulating and introspecting methods in |
912 | the Perl 5 object system. As with attributes, there are many ways to |
913 | approach this topic, so we try to keep it pretty basic, while still |
94b19069 |
914 | making it possible to extend the system in many ways. |
915 | |
552e3d24 |
916 | See L<Class::MOP::Method> for more details. |
94b19069 |
917 | |
127d39a7 |
918 | =item The Instance protocol |
919 | |
920 | This provides a layer of abstraction for creating object instances. |
921 | Since the other layers use this protocol, it is relatively easy to |
922 | change the type of your instances from the default HASH ref to other |
923 | types of references. Several examples are provided in the F<examples/> |
924 | directory included in this distribution. |
925 | |
926 | See L<Class::MOP::Instance> for more details. |
927 | |
94b19069 |
928 | =back |
929 | |
be7677c7 |
930 | =head1 FUNCTIONS |
931 | |
c1d5345a |
932 | =head2 Constants |
933 | |
934 | =over 4 |
935 | |
936 | =item I<IS_RUNNING_ON_5_10> |
937 | |
938 | We set this constant depending on what version perl we are on, this |
939 | allows us to take advantage of new 5.10 features and stay backwards |
940 | compat. |
941 | |
942 | =back |
943 | |
448b6e55 |
944 | =head2 Utility functions |
945 | |
946 | =over 4 |
947 | |
948 | =item B<load_class ($class_name)> |
949 | |
1d68af04 |
950 | This will load a given C<$class_name> and if it does not have an |
448b6e55 |
951 | already initialized metaclass, then it will intialize one for it. |
127d39a7 |
952 | This function can be used in place of tricks like |
953 | C<eval "use $module"> or using C<require>. |
448b6e55 |
954 | |
955 | =item B<is_class_loaded ($class_name)> |
956 | |
1d68af04 |
957 | This will return a boolean depending on if the C<$class_name> has |
958 | been loaded. |
448b6e55 |
959 | |
1d68af04 |
960 | NOTE: This does a basic check of the symbol table to try and |
448b6e55 |
961 | determine as best it can if the C<$class_name> is loaded, it |
1d68af04 |
962 | is probably correct about 99% of the time. |
448b6e55 |
963 | |
b1f5f41d |
964 | =item B<check_package_cache_flag ($pkg)> |
e0e4674a |
965 | |
127d39a7 |
966 | This will return an integer that is managed by C<Class::MOP::Class> |
967 | to determine if a module's symbol table has been altered. |
968 | |
969 | In Perl 5.10 or greater, this flag is package specific. However in |
970 | versions prior to 5.10, this will use the C<PL_sub_generation> variable |
971 | which is not package specific. |
972 | |
e0e4674a |
973 | =item B<get_code_info ($code)> |
974 | |
127d39a7 |
975 | This function returns two values, the name of the package the C<$code> |
976 | is from and the name of the C<$code> itself. This is used by several |
977 | elements of the MOP to detemine where a given C<$code> reference is from. |
978 | |
4c105333 |
979 | =item B<subname ($name, $code)> |
980 | |
981 | B<NOTE: DO NOT USE THIS FUNCTION, IT IS FOR INTERNAL USE ONLY!> |
982 | |
983 | If possible, we will load the L<Sub::Name> module and this will function |
984 | as C<Sub::Name::subname> does, otherwise it will just return the C<$code> |
985 | argument. |
986 | |
448b6e55 |
987 | =back |
988 | |
989 | =head2 Metaclass cache functions |
990 | |
1d68af04 |
991 | Class::MOP holds a cache of metaclasses, the following are functions |
992 | (B<not methods>) which can be used to access that cache. It is not |
993 | recommended that you mess with this, bad things could happen. But if |
be7677c7 |
994 | you are brave and willing to risk it, go for it. |
995 | |
996 | =over 4 |
997 | |
998 | =item B<get_all_metaclasses> |
999 | |
1d68af04 |
1000 | This will return an hash of all the metaclass instances that have |
1001 | been cached by B<Class::MOP::Class> keyed by the package name. |
b9d9fc0b |
1002 | |
be7677c7 |
1003 | =item B<get_all_metaclass_instances> |
1004 | |
1d68af04 |
1005 | This will return an array of all the metaclass instances that have |
b9d9fc0b |
1006 | been cached by B<Class::MOP::Class>. |
1007 | |
be7677c7 |
1008 | =item B<get_all_metaclass_names> |
1009 | |
1d68af04 |
1010 | This will return an array of all the metaclass names that have |
b9d9fc0b |
1011 | been cached by B<Class::MOP::Class>. |
1012 | |
be7677c7 |
1013 | =item B<get_metaclass_by_name ($name)> |
1014 | |
127d39a7 |
1015 | This will return a cached B<Class::MOP::Class> instance of nothing |
1016 | if no metaclass exist by that C<$name>. |
1017 | |
be7677c7 |
1018 | =item B<store_metaclass_by_name ($name, $meta)> |
1019 | |
127d39a7 |
1020 | This will store a metaclass in the cache at the supplied C<$key>. |
1021 | |
be7677c7 |
1022 | =item B<weaken_metaclass ($name)> |
1023 | |
127d39a7 |
1024 | In rare cases it is desireable to store a weakened reference in |
1025 | the metaclass cache. This function will weaken the reference to |
1026 | the metaclass stored in C<$name>. |
1027 | |
be7677c7 |
1028 | =item B<does_metaclass_exist ($name)> |
1029 | |
127d39a7 |
1030 | This will return true of there exists a metaclass stored in the |
1031 | C<$name> key and return false otherwise. |
1032 | |
be7677c7 |
1033 | =item B<remove_metaclass_by_name ($name)> |
1034 | |
127d39a7 |
1035 | This will remove a the metaclass stored in the C<$name> key. |
1036 | |
be7677c7 |
1037 | =back |
1038 | |
552e3d24 |
1039 | =head1 SEE ALSO |
8b978dd5 |
1040 | |
552e3d24 |
1041 | =head2 Books |
8b978dd5 |
1042 | |
1d68af04 |
1043 | There are very few books out on Meta Object Protocols and Metaclasses |
1044 | because it is such an esoteric topic. The following books are really |
1045 | the only ones I have found. If you know of any more, B<I<please>> |
a2e85e6c |
1046 | email me and let me know, I would love to hear about them. |
1047 | |
8b978dd5 |
1048 | =over 4 |
1049 | |
552e3d24 |
1050 | =item "The Art of the Meta Object Protocol" |
8b978dd5 |
1051 | |
552e3d24 |
1052 | =item "Advances in Object-Oriented Metalevel Architecture and Reflection" |
8b978dd5 |
1053 | |
b51af7f9 |
1054 | =item "Putting MetaClasses to Work" |
1055 | |
a2e85e6c |
1056 | =item "Smalltalk: The Language" |
1057 | |
94b19069 |
1058 | =back |
1059 | |
550d56db |
1060 | =head2 Papers |
1061 | |
1062 | =over 4 |
1063 | |
1064 | =item Uniform and safe metaclass composition |
1065 | |
1d68af04 |
1066 | An excellent paper by the people who brought us the original Traits paper. |
1067 | This paper is on how Traits can be used to do safe metaclass composition, |
1068 | and offers an excellent introduction section which delves into the topic of |
550d56db |
1069 | metaclass compatibility. |
1070 | |
1071 | L<http://www.iam.unibe.ch/~scg/Archive/Papers/Duca05ySafeMetaclassTrait.pdf> |
1072 | |
1073 | =item Safe Metaclass Programming |
1074 | |
1d68af04 |
1075 | This paper seems to precede the above paper, and propose a mix-in based |
1076 | approach as opposed to the Traits based approach. Both papers have similar |
1077 | information on the metaclass compatibility problem space. |
550d56db |
1078 | |
1079 | L<http://citeseer.ist.psu.edu/37617.html> |
1080 | |
1081 | =back |
1082 | |
552e3d24 |
1083 | =head2 Prior Art |
8b978dd5 |
1084 | |
1085 | =over 4 |
1086 | |
7184ca14 |
1087 | =item The Perl 6 MetaModel work in the Pugs project |
8b978dd5 |
1088 | |
1089 | =over 4 |
1090 | |
552e3d24 |
1091 | =item L<http://svn.openfoundry.org/pugs/perl5/Perl6-MetaModel> |
8b978dd5 |
1092 | |
552e3d24 |
1093 | =item L<http://svn.openfoundry.org/pugs/perl5/Perl6-ObjectSpace> |
8b978dd5 |
1094 | |
1095 | =back |
1096 | |
94b19069 |
1097 | =back |
1098 | |
1d68af04 |
1099 | =head2 Articles |
f8dfcfb7 |
1100 | |
1101 | =over 4 |
1102 | |
1d68af04 |
1103 | =item CPAN Module Review of Class::MOP |
f8dfcfb7 |
1104 | |
1105 | L<http://www.oreillynet.com/onlamp/blog/2006/06/cpan_module_review_classmop.html> |
1106 | |
1107 | =back |
1108 | |
a2e85e6c |
1109 | =head1 SIMILAR MODULES |
1110 | |
1d68af04 |
1111 | As I have said above, this module is a class-builder-builder, so it is |
1112 | not the same thing as modules like L<Class::Accessor> and |
1113 | L<Class::MethodMaker>. That being said there are very few modules on CPAN |
1114 | with similar goals to this module. The one I have found which is most |
1115 | like this module is L<Class::Meta>, although it's philosophy and the MOP it |
1116 | creates are very different from this modules. |
94b19069 |
1117 | |
a2e85e6c |
1118 | =head1 BUGS |
1119 | |
1d68af04 |
1120 | All complex software has bugs lurking in it, and this module is no |
a2e85e6c |
1121 | exception. If you find a bug please either email me, or add the bug |
1122 | to cpan-RT. |
1123 | |
1124 | =head1 ACKNOWLEDGEMENTS |
1125 | |
1126 | =over 4 |
1127 | |
b9d9fc0b |
1128 | =item Rob Kinyon |
a2e85e6c |
1129 | |
1d68af04 |
1130 | Thanks to Rob for actually getting the development of this module kick-started. |
a2e85e6c |
1131 | |
1132 | =back |
1133 | |
1a09d9cc |
1134 | =head1 AUTHORS |
94b19069 |
1135 | |
a2e85e6c |
1136 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
552e3d24 |
1137 | |
9c8cda90 |
1138 | B<with contributions from:> |
1139 | |
1140 | Brandon (blblack) Black |
1141 | |
1142 | Guillermo (groditi) Roditi |
1143 | |
9195ddff |
1144 | Matt (mst) Trout |
1145 | |
9c8cda90 |
1146 | Rob (robkinyon) Kinyon |
1147 | |
1148 | Yuval (nothingmuch) Kogman |
1a09d9cc |
1149 | |
f430cfa4 |
1150 | Scott (konobi) McWhirter |
1151 | |
94b19069 |
1152 | =head1 COPYRIGHT AND LICENSE |
1153 | |
69e3ab0a |
1154 | Copyright 2006-2008 by Infinity Interactive, Inc. |
94b19069 |
1155 | |
1156 | L<http://www.iinteractive.com> |
1157 | |
1158 | This library is free software; you can redistribute it and/or modify |
1d68af04 |
1159 | it under the same terms as Perl itself. |
94b19069 |
1160 | |
1161 | =cut |