Commit | Line | Data |
fcd84ca9 |
1 | |
2 | package Moose; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
a94188ac |
7 | our $VERSION = '0.56'; |
d44714be |
8 | our $AUTHORITY = 'cpan:STEVAN'; |
fcd84ca9 |
9 | |
21f1e231 |
10 | use Scalar::Util 'blessed'; |
c0b37457 |
11 | use Carp 'confess', 'croak', 'cluck'; |
fcd84ca9 |
12 | |
5bd4db9b |
13 | use Moose::Exporter; |
7f18097c |
14 | |
46217c9c |
15 | use Class::MOP 0.64; |
ef1d5f4b |
16 | |
c0e30cf5 |
17 | use Moose::Meta::Class; |
7415b2cb |
18 | use Moose::Meta::TypeConstraint; |
7c13858b |
19 | use Moose::Meta::TypeCoercion; |
78cd1d3b |
20 | use Moose::Meta::Attribute; |
ddd0ec20 |
21 | use Moose::Meta::Instance; |
c0e30cf5 |
22 | |
d67145ed |
23 | use Moose::Meta::Role; |
24 | |
fcd84ca9 |
25 | use Moose::Object; |
7415b2cb |
26 | use Moose::Util::TypeConstraints; |
d7d8a8c7 |
27 | use Moose::Util (); |
a15dff8d |
28 | |
5bd4db9b |
29 | sub extends { |
97a93056 |
30 | my $class = shift; |
3d544ed5 |
31 | |
5bd4db9b |
32 | croak "Must derive at least one class" unless @_; |
9bcfbab1 |
33 | |
5bd4db9b |
34 | my @supers = @_; |
35 | foreach my $super (@supers) { |
36 | Class::MOP::load_class($super); |
37 | croak "You cannot inherit from a Moose Role ($super)" |
38 | if $super->can('meta') && |
39 | blessed $super->meta && |
40 | $super->meta->isa('Moose::Meta::Role') |
c92c1205 |
41 | } |
5bee491d |
42 | |
26fbace8 |
43 | |
86dd5d11 |
44 | |
5bd4db9b |
45 | # this checks the metaclass to make sure |
46 | # it is correct, sometimes it can get out |
47 | # of sync when the classes are being built |
48 | my $meta = $class->meta->_fix_metaclass_incompatability(@supers); |
49 | $meta->superclasses(@supers); |
50 | } |
a3c7e2fe |
51 | |
5bd4db9b |
52 | sub with { |
97a93056 |
53 | my $class = shift; |
5bd4db9b |
54 | Moose::Util::apply_all_roles($class->meta, @_); |
55 | } |
9bcfbab1 |
56 | |
5bd4db9b |
57 | sub has { |
97a93056 |
58 | my $class = shift; |
5bd4db9b |
59 | my $name = shift; |
60 | croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1; |
61 | my %options = @_; |
62 | my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ]; |
63 | $class->meta->add_attribute( $_, %options ) for @$attrs; |
64 | } |
9bcfbab1 |
65 | |
5bd4db9b |
66 | sub before { |
97a93056 |
67 | my $class = shift; |
5bd4db9b |
68 | Moose::Util::add_method_modifier($class, 'before', \@_); |
69 | } |
70 | |
71 | sub after { |
97a93056 |
72 | my $class = shift; |
5bd4db9b |
73 | Moose::Util::add_method_modifier($class, 'after', \@_); |
74 | } |
75 | |
76 | sub around { |
97a93056 |
77 | my $class = shift; |
5bd4db9b |
78 | Moose::Util::add_method_modifier($class, 'around', \@_); |
79 | } |
80 | |
81 | sub super { |
82 | return unless our $SUPER_BODY; $SUPER_BODY->(our @SUPER_ARGS); |
83 | } |
9bcfbab1 |
84 | |
5bd4db9b |
85 | sub override { |
97a93056 |
86 | my $class = shift; |
5bd4db9b |
87 | my ( $name, $method ) = @_; |
88 | $class->meta->add_override_method_modifier( $name => $method ); |
89 | } |
9bcfbab1 |
90 | |
5bd4db9b |
91 | sub inner { |
92 | my $pkg = caller(); |
93 | our ( %INNER_BODY, %INNER_ARGS ); |
94 | |
95 | if ( my $body = $INNER_BODY{$pkg} ) { |
96 | my @args = @{ $INNER_ARGS{$pkg} }; |
97 | local $INNER_ARGS{$pkg}; |
98 | local $INNER_BODY{$pkg}; |
99 | return $body->(@args); |
100 | } else { |
101 | return; |
ce265cc3 |
102 | } |
5bd4db9b |
103 | } |
9bcfbab1 |
104 | |
5bd4db9b |
105 | sub augment { |
97a93056 |
106 | my $class = shift; |
5bd4db9b |
107 | my ( $name, $method ) = @_; |
108 | $class->meta->add_augment_method_modifier( $name => $method ); |
ce265cc3 |
109 | } |
9bcfbab1 |
110 | |
5bd4db9b |
111 | sub make_immutable { |
97a93056 |
112 | my $class = shift; |
5bd4db9b |
113 | cluck "The make_immutable keyword has been deprecated, " . |
114 | "please go back to __PACKAGE__->meta->make_immutable\n"; |
115 | $class->meta->make_immutable(@_); |
116 | } |
9bcfbab1 |
117 | |
a5c426fc |
118 | my $exporter = Moose::Exporter->build_import_methods( |
97a93056 |
119 | with_caller => [ |
120 | qw( extends with has before after around override augment make_immutable ) |
121 | ], |
122 | as_is => [ |
123 | qw( super inner ), |
5bd4db9b |
124 | \&Carp::confess, |
125 | \&Scalar::Util::blessed, |
126 | ], |
127 | ); |
128 | |
0338a411 |
129 | # This exists for backwards compat |
cc841c0e |
130 | sub init_meta { |
131 | my ( $class, $base_class, $metaclass ) = @_; |
0338a411 |
132 | |
133 | __PACKAGE__->_init_meta( for_class => $class, |
134 | object_base_class => $base_class, |
135 | metaclass_class => $metaclass, |
136 | ); |
137 | } |
138 | |
139 | sub _init_meta { |
140 | shift; |
141 | my %args = @_; |
142 | |
143 | my $class = $args{for_class} |
144 | or confess "Cannot call _init_meta without specifying a for_class"; |
145 | my $base_class = $args{object_base_class} || 'Moose::Object'; |
146 | my $metaclass = $args{metaclass_class} || 'Moose::Meta::Class'; |
cc841c0e |
147 | |
148 | confess |
149 | "The Metaclass $metaclass must be a subclass of Moose::Meta::Class." |
150 | unless $metaclass->isa('Moose::Meta::Class'); |
151 | |
152 | # make a subtype for each Moose class |
153 | class_type($class) |
154 | unless find_type_constraint($class); |
155 | |
156 | my $meta; |
157 | if ( $class->can('meta') ) { |
158 | # NOTE: |
159 | # this is the case where the metaclass pragma |
160 | # was used before the 'use Moose' statement to |
161 | # override a specific class |
162 | $meta = $class->meta(); |
163 | ( blessed($meta) && $meta->isa('Moose::Meta::Class') ) |
164 | || confess "You already have a &meta function, but it does not return a Moose::Meta::Class"; |
165 | } |
166 | else { |
167 | # NOTE: |
168 | # this is broken currently, we actually need |
169 | # to allow the possiblity of an inherited |
170 | # meta, which will not be visible until the |
171 | # user 'extends' first. This needs to have |
172 | # more intelligence to it |
173 | $meta = $metaclass->initialize($class); |
174 | $meta->add_method( |
175 | 'meta' => sub { |
176 | # re-initialize so it inherits properly |
177 | $metaclass->initialize( blessed( $_[0] ) || $_[0] ); |
178 | } |
179 | ); |
180 | } |
181 | |
182 | # make sure they inherit from Moose::Object |
183 | $meta->superclasses($base_class) |
184 | unless $meta->superclasses(); |
185 | |
186 | return $meta; |
187 | } |
188 | |
8ecb1fa0 |
189 | ## make 'em all immutable |
190 | |
191 | $_->meta->make_immutable( |
192 | inline_constructor => 0, |
77a18c28 |
193 | inline_accessors => 1, # these are Class::MOP accessors, so they need inlining |
9bcfbab1 |
194 | ) |
195 | for ( |
8ecb1fa0 |
196 | 'Moose::Meta::Attribute', |
197 | 'Moose::Meta::Class', |
198 | 'Moose::Meta::Instance', |
199 | |
200 | 'Moose::Meta::TypeConstraint', |
201 | 'Moose::Meta::TypeConstraint::Union', |
0fbd4b0a |
202 | 'Moose::Meta::TypeConstraint::Parameterized', |
8ecb1fa0 |
203 | 'Moose::Meta::TypeCoercion', |
204 | |
205 | 'Moose::Meta::Method', |
206 | 'Moose::Meta::Method::Accessor', |
207 | 'Moose::Meta::Method::Constructor', |
9bcfbab1 |
208 | 'Moose::Meta::Method::Destructor', |
8ecb1fa0 |
209 | 'Moose::Meta::Method::Overriden', |
d67145ed |
210 | |
211 | 'Moose::Meta::Role', |
9bcfbab1 |
212 | 'Moose::Meta::Role::Method', |
213 | 'Moose::Meta::Role::Method::Required', |
214 | ); |
8ecb1fa0 |
215 | |
fcd84ca9 |
216 | 1; |
217 | |
218 | __END__ |
219 | |
220 | =pod |
221 | |
222 | =head1 NAME |
223 | |
8bdc7f13 |
224 | Moose - A postmodern object system for Perl 5 |
fcd84ca9 |
225 | |
226 | =head1 SYNOPSIS |
e522431d |
227 | |
228 | package Point; |
1cd45431 |
229 | use Moose; # automatically turns on strict and warnings |
26fbace8 |
230 | |
43d599e5 |
231 | has 'x' => (is => 'rw', isa => 'Int'); |
232 | has 'y' => (is => 'rw', isa => 'Int'); |
26fbace8 |
233 | |
e522431d |
234 | sub clear { |
235 | my $self = shift; |
236 | $self->x(0); |
26fbace8 |
237 | $self->y(0); |
e522431d |
238 | } |
26fbace8 |
239 | |
e522431d |
240 | package Point3D; |
241 | use Moose; |
26fbace8 |
242 | |
e522431d |
243 | extends 'Point'; |
26fbace8 |
244 | |
43d599e5 |
245 | has 'z' => (is => 'rw', isa => 'Int'); |
26fbace8 |
246 | |
e522431d |
247 | after 'clear' => sub { |
248 | my $self = shift; |
43d599e5 |
249 | $self->z(0); |
26fbace8 |
250 | }; |
2c0cbef7 |
251 | |
fcd84ca9 |
252 | =head1 DESCRIPTION |
253 | |
26fbace8 |
254 | Moose is an extension of the Perl 5 object system. |
e522431d |
255 | |
9b9da6f1 |
256 | The main goal of Moose is to make Perl 5 Object Oriented programming |
257 | easier, more consistent and less tedious. With Moose you can to think |
258 | more about what you want to do and less about the mechanics of OOP. |
fcd84ca9 |
259 | |
9b9da6f1 |
260 | Additionally, Moose is built on top of L<Class::MOP>, which is a |
261 | metaclass system for Perl 5. This means that Moose not only makes |
262 | building normal Perl 5 objects better, but it provides the power of |
263 | metaclass programming as well. |
8bdc7f13 |
264 | |
28669f89 |
265 | =head2 Moose Extensions |
266 | |
12aed9a0 |
267 | The C<MooseX::> namespace is the official place to find Moose extensions. |
268 | These extensions can be found on the CPAN. The easiest way to find them |
269 | is to search for them (L<http://search.cpan.org/search?query=MooseX::>), |
270 | or to examine L<Task::Moose> which aims to keep an up-to-date, easily |
271 | installable list of Moose extensions. |
28669f89 |
272 | |
6ba6d68c |
273 | =head1 BUILDING CLASSES WITH MOOSE |
274 | |
68efb014 |
275 | Moose makes every attempt to provide as much convenience as possible during |
276 | class construction/definition, but still stay out of your way if you want it |
277 | to. Here are a few items to note when building classes with Moose. |
6ba6d68c |
278 | |
26fbace8 |
279 | Unless specified with C<extends>, any class which uses Moose will |
6ba6d68c |
280 | inherit from L<Moose::Object>. |
281 | |
1cd45431 |
282 | Moose will also manage all attributes (including inherited ones) that are |
283 | defined with C<has>. And (assuming you call C<new>, which is inherited from |
284 | L<Moose::Object>) this includes properly initializing all instance slots, |
285 | setting defaults where appropriate, and performing any type constraint checking |
286 | or coercion. |
6ba6d68c |
287 | |
004222dc |
288 | =head1 PROVIDED METHODS |
6ba6d68c |
289 | |
004222dc |
290 | Moose provides a number of methods to all your classes, mostly through the |
291 | inheritance of L<Moose::Object>. There is however, one exception. |
6ba6d68c |
292 | |
293 | =over 4 |
294 | |
295 | =item B<meta> |
296 | |
297 | This is a method which provides access to the current class's metaclass. |
298 | |
004222dc |
299 | =back |
300 | |
301 | =head1 EXPORTED FUNCTIONS |
302 | |
303 | Moose will export a number of functions into the class's namespace which |
304 | may then be used to set up the class. These functions all work directly |
305 | on the current class. |
306 | |
307 | =over 4 |
308 | |
6ba6d68c |
309 | =item B<extends (@superclasses)> |
310 | |
311 | This function will set the superclass(es) for the current class. |
312 | |
26fbace8 |
313 | This approach is recommended instead of C<use base>, because C<use base> |
314 | actually C<push>es onto the class's C<@ISA>, whereas C<extends> will |
315 | replace it. This is important to ensure that classes which do not have |
68efb014 |
316 | superclasses still properly inherit from L<Moose::Object>. |
6ba6d68c |
317 | |
43d599e5 |
318 | =item B<with (@roles)> |
e9ec68d6 |
319 | |
004222dc |
320 | This will apply a given set of C<@roles> to the local class. |
e9ec68d6 |
321 | |
cd7eeaf5 |
322 | =item B<has $name =E<gt> %options> |
6ba6d68c |
323 | |
26fbace8 |
324 | This will install an attribute of a given C<$name> into the current class. |
325 | The C<%options> are the same as those provided by |
326 | L<Class::MOP::Attribute>, in addition to the list below which are provided |
43d599e5 |
327 | by Moose (L<Moose::Meta::Attribute> to be more specific): |
6ba6d68c |
328 | |
329 | =over 4 |
330 | |
076c81ed |
331 | =item I<is =E<gt> 'rw'|'ro'> |
6ba6d68c |
332 | |
26fbace8 |
333 | The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read |
334 | only). These will create either a read/write accessor or a read-only |
6ba6d68c |
335 | accessor respectively, using the same name as the C<$name> of the attribute. |
336 | |
1cd45431 |
337 | If you need more control over how your accessors are named, you can use the |
338 | I<reader>, I<writer> and I<accessor> options inherited from |
004222dc |
339 | L<Class::MOP::Attribute>, however if you use those, you won't need the I<is> |
340 | option. |
6ba6d68c |
341 | |
076c81ed |
342 | =item I<isa =E<gt> $type_name> |
6ba6d68c |
343 | |
26fbace8 |
344 | The I<isa> option uses Moose's type constraint facilities to set up runtime |
345 | type checking for this attribute. Moose will perform the checks during class |
346 | construction, and within any accessors. The C<$type_name> argument must be a |
347 | string. The string may be either a class name or a type defined using |
9cca2e9e |
348 | Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints> |
c2a69ef1 |
349 | for information on how to define a new type, and how to retrieve type meta-data). |
6ba6d68c |
350 | |
daea75c9 |
351 | =item I<coerce =E<gt> (1|0)> |
352 | |
26fbace8 |
353 | This will attempt to use coercion with the supplied type constraint to change |
354 | the value passed into any accessors or constructors. You B<must> have supplied |
5cfe3805 |
355 | a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5> |
1cd45431 |
356 | for an example. |
daea75c9 |
357 | |
358 | =item I<does =E<gt> $role_name> |
359 | |
26fbace8 |
360 | This will accept the name of a role which the value stored in this attribute |
daea75c9 |
361 | is expected to have consumed. |
362 | |
363 | =item I<required =E<gt> (1|0)> |
364 | |
26fbace8 |
365 | This marks the attribute as being required. This means a I<defined> value must be |
366 | supplied during class construction, and the attribute may never be set to |
367 | C<undef> with an accessor. |
daea75c9 |
368 | |
369 | =item I<weak_ref =E<gt> (1|0)> |
370 | |
68efb014 |
371 | This will tell the class to store the value of this attribute as a weakened |
372 | reference. If an attribute is a weakened reference, it B<cannot> also be |
373 | coerced. |
daea75c9 |
374 | |
375 | =item I<lazy =E<gt> (1|0)> |
376 | |
26fbace8 |
377 | This will tell the class to not create this slot until absolutely necessary. |
daea75c9 |
378 | If an attribute is marked as lazy it B<must> have a default supplied. |
379 | |
9e93dd19 |
380 | =item I<auto_deref =E<gt> (1|0)> |
381 | |
26fbace8 |
382 | This tells the accessor whether to automatically dereference the value returned. |
1cd45431 |
383 | This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>. |
9e93dd19 |
384 | |
65e14c86 |
385 | =item I<trigger =E<gt> $code> |
386 | |
387 | The I<trigger> option is a CODE reference which will be called after the value of |
388 | the attribute is set. The CODE ref will be passed the instance itself, the |
389 | updated value and the attribute meta-object (this is for more advanced fiddling |
390 | and can typically be ignored). You B<cannot> have a trigger on a read-only |
391 | attribute. |
daea75c9 |
392 | |
c84f324f |
393 | =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE> |
2c0cbef7 |
394 | |
26fbace8 |
395 | The I<handles> option provides Moose classes with automated delegation features. |
396 | This is a pretty complex and powerful option. It accepts many different option |
397 | formats, each with its own benefits and drawbacks. |
38e3283b |
398 | |
1cd45431 |
399 | B<NOTE:> The class being delegated to does not need to be a Moose based class, |
400 | which is why this feature is especially useful when wrapping non-Moose classes. |
38e3283b |
401 | |
1cd45431 |
402 | All I<handles> option formats share the following traits: |
38e3283b |
403 | |
1cd45431 |
404 | You cannot override a locally defined method with a delegated method; an |
405 | exception will be thrown if you try. That is to say, if you define C<foo> in |
406 | your class, you cannot override it with a delegated C<foo>. This is almost never |
407 | something you would want to do, and if it is, you should do it by hand and not |
408 | use Moose. |
38e3283b |
409 | |
1cd45431 |
410 | You cannot override any of the methods found in Moose::Object, or the C<BUILD> |
411 | and C<DEMOLISH> methods. These will not throw an exception, but will silently |
412 | move on to the next method in the list. My reasoning for this is that you would |
413 | almost never want to do this, since it usually breaks your class. As with |
414 | overriding locally defined methods, if you do want to do this, you should do it |
415 | manually, not with Moose. |
38e3283b |
416 | |
f3c4e20e |
417 | You do not I<need> to have a reader (or accessor) for the attribute in order |
418 | to delegate to it. Moose will create a means of accessing the value for you, |
419 | however this will be several times B<less> efficient then if you had given |
420 | the attribute a reader (or accessor) to use. |
421 | |
38e3283b |
422 | Below is the documentation for each option format: |
423 | |
424 | =over 4 |
425 | |
426 | =item C<ARRAY> |
427 | |
26fbace8 |
428 | This is the most common usage for I<handles>. You basically pass a list of |
429 | method names to be delegated, and Moose will install a delegation method |
1cd45431 |
430 | for each one. |
38e3283b |
431 | |
432 | =item C<HASH> |
433 | |
26fbace8 |
434 | This is the second most common usage for I<handles>. Instead of a list of |
435 | method names, you pass a HASH ref where each key is the method name you |
436 | want installed locally, and its value is the name of the original method |
437 | in the class being delegated to. |
fd595040 |
438 | |
26fbace8 |
439 | This can be very useful for recursive classes like trees. Here is a |
5cfe3805 |
440 | quick example (soon to be expanded into a Moose::Cookbook recipe): |
38e3283b |
441 | |
1cd45431 |
442 | package Tree; |
38e3283b |
443 | use Moose; |
26fbace8 |
444 | |
38e3283b |
445 | has 'node' => (is => 'rw', isa => 'Any'); |
26fbace8 |
446 | |
38e3283b |
447 | has 'children' => ( |
448 | is => 'ro', |
449 | isa => 'ArrayRef', |
450 | default => sub { [] } |
451 | ); |
26fbace8 |
452 | |
38e3283b |
453 | has 'parent' => ( |
454 | is => 'rw', |
455 | isa => 'Tree', |
a4e516f6 |
456 | weak_ref => 1, |
38e3283b |
457 | handles => { |
458 | parent_node => 'node', |
26fbace8 |
459 | siblings => 'children', |
38e3283b |
460 | } |
461 | ); |
462 | |
1cd45431 |
463 | In this example, the Tree package gets C<parent_node> and C<siblings> methods, |
464 | which delegate to the C<node> and C<children> methods (respectively) of the Tree |
26fbace8 |
465 | instance stored in the C<parent> slot. |
38e3283b |
466 | |
467 | =item C<REGEXP> |
468 | |
26fbace8 |
469 | The regexp option works very similar to the ARRAY option, except that it builds |
470 | the list of methods for you. It starts by collecting all possible methods of the |
471 | class being delegated to, then filters that list using the regexp supplied here. |
38e3283b |
472 | |
26fbace8 |
473 | B<NOTE:> An I<isa> option is required when using the regexp option format. This |
474 | is so that we can determine (at compile time) the method list from the class. |
38e3283b |
475 | Without an I<isa> this is just not possible. |
476 | |
c84f324f |
477 | =item C<ROLE> |
478 | |
26fbace8 |
479 | With the role option, you specify the name of a role whose "interface" then |
480 | becomes the list of methods to handle. The "interface" can be defined as; the |
481 | methods of the role and any required methods of the role. It should be noted |
482 | that this does B<not> include any method modifiers or generated attribute |
c84f324f |
483 | methods (which is consistent with role composition). |
484 | |
38e3283b |
485 | =item C<CODE> |
486 | |
1cd45431 |
487 | This is the option to use when you really want to do something funky. You should |
488 | only use it if you really know what you are doing, as it involves manual |
489 | metaclass twiddling. |
38e3283b |
490 | |
1cd45431 |
491 | This takes a code reference, which should expect two arguments. The first is the |
492 | attribute meta-object this I<handles> is attached to. The second is the |
493 | metaclass of the class being delegated to. It expects you to return a hash (not |
26fbace8 |
494 | a HASH ref) of the methods you want mapped. |
38e3283b |
495 | |
496 | =back |
2c0cbef7 |
497 | |
004222dc |
498 | =item I<metaclass =E<gt> $metaclass_name> |
499 | |
500 | This tells the class to use a custom attribute metaclass for this particular |
501 | attribute. Custom attribute metaclasses are useful for extending the |
502 | capabilities of the I<has> keyword: they are the simplest way to extend the MOP, |
503 | but they are still a fairly advanced topic and too much to cover here, see |
5cfe3805 |
504 | L<Moose::Cookbook::Meta::Recipe1> for more information. |
004222dc |
505 | |
506 | The default behavior here is to just load C<$metaclass_name>; however, we also |
507 | have a way to alias to a shorter name. This will first look to see if |
508 | B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose |
509 | will then check to see if that has the method C<register_implementation>, which |
510 | should return the actual name of the custom attribute metaclass. If there is no |
511 | C<register_implementation> method, it will fall back to using |
512 | B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name. |
513 | |
514 | =item I<traits =E<gt> [ @role_names ]> |
515 | |
516 | This tells Moose to take the list of C<@role_names> and apply them to the |
517 | attribute meta-object. This is very similar to the I<metaclass> option, but |
518 | allows you to use more than one extension at a time. This too is an advanced |
519 | topic, we don't yet have a cookbook for it though. |
520 | |
521 | As with I<metaclass>, the default behavior is to just load C<$role_name>; however, |
522 | we also have a way to alias to a shorter name. This will first look to see if |
523 | B<Moose::Meta::Attribute::Custom::Trait::$role_name> exists. If it does, Moose |
524 | will then check to see if that has the method C<register_implementation>, which |
525 | should return the actual name of the custom attribute trait. If there is no |
526 | C<register_implementation> method, it will fall back to using |
527 | B<Moose::Meta::Attribute::Custom::Trait::$metaclass_name> as the trait name. |
528 | |
6ba6d68c |
529 | =back |
530 | |
cd7eeaf5 |
531 | =item B<has +$name =E<gt> %options> |
532 | |
26fbace8 |
533 | This is variation on the normal attibute creator C<has> which allows you to |
8d62bf6d |
534 | clone and extend an attribute from a superclass or from a role. Here is an |
535 | example of the superclass usage: |
cd7eeaf5 |
536 | |
537 | package Foo; |
538 | use Moose; |
26fbace8 |
539 | |
cd7eeaf5 |
540 | has 'message' => ( |
26fbace8 |
541 | is => 'rw', |
cd7eeaf5 |
542 | isa => 'Str', |
543 | default => 'Hello, I am a Foo' |
544 | ); |
26fbace8 |
545 | |
cd7eeaf5 |
546 | package My::Foo; |
547 | use Moose; |
26fbace8 |
548 | |
cd7eeaf5 |
549 | extends 'Foo'; |
26fbace8 |
550 | |
cd7eeaf5 |
551 | has '+message' => (default => 'Hello I am My::Foo'); |
552 | |
1cd45431 |
553 | What is happening here is that B<My::Foo> is cloning the C<message> attribute |
554 | from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt> |
555 | 'Str'> characteristics, but changing the value in C<default>. |
cd7eeaf5 |
556 | |
8d62bf6d |
557 | Here is another example, but within the context of a role: |
558 | |
559 | package Foo::Role; |
560 | use Moose::Role; |
986d175a |
561 | |
8d62bf6d |
562 | has 'message' => ( |
563 | is => 'rw', |
564 | isa => 'Str', |
565 | default => 'Hello, I am a Foo' |
566 | ); |
986d175a |
567 | |
8d62bf6d |
568 | package My::Foo; |
569 | use Moose; |
986d175a |
570 | |
8d62bf6d |
571 | with 'Foo::Role'; |
986d175a |
572 | |
8d62bf6d |
573 | has '+message' => (default => 'Hello I am My::Foo'); |
574 | |
575 | In this case, we are basically taking the attribute which the role supplied |
4032c9bb |
576 | and altering it within the bounds of this feature. |
8d62bf6d |
577 | |
4032c9bb |
578 | Aside from where the attributes come from (one from superclass, the other |
579 | from a role), this feature works exactly the same. This feature is restricted |
580 | somewhat, so as to try and force at least I<some> sanity into it. You are only |
581 | allowed to change the following attributes: |
cd7eeaf5 |
582 | |
583 | =over 4 |
584 | |
26fbace8 |
585 | =item I<default> |
cd7eeaf5 |
586 | |
587 | Change the default value of an attribute. |
588 | |
26fbace8 |
589 | =item I<coerce> |
cd7eeaf5 |
590 | |
591 | Change whether the attribute attempts to coerce a value passed to it. |
592 | |
26fbace8 |
593 | =item I<required> |
cd7eeaf5 |
594 | |
595 | Change if the attribute is required to have a value. |
596 | |
597 | =item I<documentation> |
598 | |
599 | Change the documentation string associated with the attribute. |
600 | |
83cc9094 |
601 | =item I<lazy> |
602 | |
603 | Change if the attribute lazily initializes the slot. |
604 | |
cd7eeaf5 |
605 | =item I<isa> |
606 | |
aed87761 |
607 | You I<are> allowed to change the type without restriction. |
608 | |
609 | It is recommended that you use this freedom with caution. We used to |
610 | only allow for extension only if the type was a subtype of the parent's |
611 | type, but we felt that was too restrictive and is better left as a |
612 | policy descision. |
cd7eeaf5 |
613 | |
83cc9094 |
614 | =item I<handles> |
615 | |
26fbace8 |
616 | You are allowed to B<add> a new C<handles> definition, but you are B<not> |
617 | allowed to I<change> one. |
83cc9094 |
618 | |
8d62bf6d |
619 | =item I<builder> |
620 | |
621 | You are allowed to B<add> a new C<builder> definition, but you are B<not> |
622 | allowed to I<change> one. |
623 | |
13284479 |
624 | =item I<metaclass> |
625 | |
626 | You are allowed to B<add> a new C<metaclass> definition, but you are |
627 | B<not> allowed to I<change> one. |
628 | |
629 | =item I<traits> |
630 | |
631 | You are allowed to B<add> additional traits to the C<traits> definition. |
632 | These traits will be composed into the attribute, but pre-existing traits |
633 | B<are not> overridden, or removed. |
634 | |
cd7eeaf5 |
635 | =back |
636 | |
076c81ed |
637 | =item B<before $name|@names =E<gt> sub { ... }> |
6ba6d68c |
638 | |
076c81ed |
639 | =item B<after $name|@names =E<gt> sub { ... }> |
6ba6d68c |
640 | |
076c81ed |
641 | =item B<around $name|@names =E<gt> sub { ... }> |
6ba6d68c |
642 | |
d8af92ae |
643 | This three items are syntactic sugar for the before, after, and around method |
644 | modifier features that L<Class::MOP> provides. More information on these may be |
645 | found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method |
646 | Modifiers"> for now. |
6ba6d68c |
647 | |
159da176 |
648 | =item B<super> |
649 | |
26fbace8 |
650 | The keyword C<super> is a no-op when called outside of an C<override> method. In |
651 | the context of an C<override> method, it will call the next most appropriate |
159da176 |
652 | superclass method with the same arguments as the original method. |
653 | |
654 | =item B<override ($name, &sub)> |
655 | |
26fbace8 |
656 | An C<override> method is a way of explicitly saying "I am overriding this |
657 | method from my superclass". You can call C<super> within this method, and |
658 | it will work as expected. The same thing I<can> be accomplished with a normal |
659 | method call and the C<SUPER::> pseudo-package; it is really your choice. |
159da176 |
660 | |
661 | =item B<inner> |
662 | |
26fbace8 |
663 | The keyword C<inner>, much like C<super>, is a no-op outside of the context of |
664 | an C<augment> method. You can think of C<inner> as being the inverse of |
68efb014 |
665 | C<super>; the details of how C<inner> and C<augment> work is best described in |
5cfe3805 |
666 | the L<Moose::Cookbook::Basics::Recipe6>. |
159da176 |
667 | |
668 | =item B<augment ($name, &sub)> |
669 | |
26fbace8 |
670 | An C<augment> method, is a way of explicitly saying "I am augmenting this |
671 | method from my superclass". Once again, the details of how C<inner> and |
5cfe3805 |
672 | C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>. |
159da176 |
673 | |
6ba6d68c |
674 | =item B<confess> |
675 | |
68efb014 |
676 | This is the C<Carp::confess> function, and exported here because I use it |
004222dc |
677 | all the time. |
6ba6d68c |
678 | |
679 | =item B<blessed> |
680 | |
1cd45431 |
681 | This is the C<Scalar::Util::blessed> function, it is exported here because I |
26fbace8 |
682 | use it all the time. It is highly recommended that this is used instead of |
6ba6d68c |
683 | C<ref> anywhere you need to test for an object's class name. |
684 | |
685 | =back |
686 | |
1cd45431 |
687 | =head1 UNIMPORTING FUNCTIONS |
31f8ec72 |
688 | |
689 | =head2 B<unimport> |
690 | |
1cd45431 |
691 | Moose offers a way to remove the keywords it exports, through the C<unimport> |
31f8ec72 |
692 | method. You simply have to say C<no Moose> at the bottom of your code for this |
693 | to work. Here is an example: |
694 | |
695 | package Person; |
696 | use Moose; |
697 | |
698 | has 'first_name' => (is => 'rw', isa => 'Str'); |
699 | has 'last_name' => (is => 'rw', isa => 'Str'); |
26fbace8 |
700 | |
701 | sub full_name { |
31f8ec72 |
702 | my $self = shift; |
26fbace8 |
703 | $self->first_name . ' ' . $self->last_name |
31f8ec72 |
704 | } |
26fbace8 |
705 | |
706 | no Moose; # keywords are removed from the Person package |
31f8ec72 |
707 | |
9bcfbab1 |
708 | =head1 EXTENDING AND EMBEDDING MOOSE |
709 | |
26fbace8 |
710 | Moose also offers some options for extending or embedding it into your own |
9bcfbab1 |
711 | framework. The basic premise is to have something that sets up your class' |
26fbace8 |
712 | metaclass and export the moose declarators (C<has>, C<with>, C<extends>,...). |
9bcfbab1 |
713 | Here is an example: |
714 | |
715 | package MyFramework; |
716 | use Moose; |
26fbace8 |
717 | |
9bcfbab1 |
718 | sub import { |
719 | my $CALLER = caller(); |
720 | |
721 | strict->import; |
722 | warnings->import; |
723 | |
724 | # we should never export to main |
725 | return if $CALLER eq 'main'; |
726 | Moose::init_meta( $CALLER, 'MyFramework::Base' ); |
727 | Moose->import({into => $CALLER}); |
728 | |
729 | # Do my custom framework stuff |
26fbace8 |
730 | |
9bcfbab1 |
731 | return 1; |
732 | } |
26fbace8 |
733 | |
9bcfbab1 |
734 | =head2 B<import> |
735 | |
77a18c28 |
736 | Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}> |
9bcfbab1 |
737 | and C<{into_level =E<gt> 1}> |
738 | |
739 | =head2 B<init_meta ($class, $baseclass, $metaclass)> |
740 | |
26fbace8 |
741 | Moose does some boot strapping: it creates a metaclass object for your class, |
742 | and then injects a C<meta> accessor into your class to retrieve it. Then it |
743 | sets your baseclass to Moose::Object or the value you pass in unless you already |
744 | have one. This is all done via C<init_meta> which takes the name of your class |
2bbba362 |
745 | and optionally a baseclass and a metaclass as arguments. |
26fbace8 |
746 | |
80837fe1 |
747 | For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>. |
748 | |
05d9eaf6 |
749 | =head1 CAVEATS |
750 | |
751 | =over 4 |
752 | |
753 | =item * |
754 | |
1cd45431 |
755 | It should be noted that C<super> and C<inner> B<cannot> be used in the same |
756 | method. However, they may be combined within the same class hierarchy; see |
757 | F<t/014_override_augment_inner_super.t> for an example. |
05d9eaf6 |
758 | |
26fbace8 |
759 | The reason for this is that C<super> is only valid within a method |
760 | with the C<override> modifier, and C<inner> will never be valid within an |
761 | C<override> method. In fact, C<augment> will skip over any C<override> methods |
68efb014 |
762 | when searching for its appropriate C<inner>. |
05d9eaf6 |
763 | |
1cd45431 |
764 | This might seem like a restriction, but I am of the opinion that keeping these |
765 | two features separate (yet interoperable) actually makes them easy to use, since |
766 | their behavior is then easier to predict. Time will tell whether I am right or |
c84f324f |
767 | not (UPDATE: so far so good). |
05d9eaf6 |
768 | |
004222dc |
769 | =item * |
770 | |
771 | It is important to note that we currently have no simple way of combining |
772 | multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above), |
773 | and that in many cases they will conflict with one another. We are working on |
774 | developing a way around this issue, but in the meantime, you have been warned. |
775 | |
05d9eaf6 |
776 | =back |
777 | |
9b9da6f1 |
778 | =head1 JUSTIFICATION |
779 | |
780 | In case you are still asking yourself "Why do I need this?", then this |
781 | section is for you. This used to be part of the main DESCRIPTION, but |
782 | I think Moose no longer actually needs justification, so it is included |
783 | (read: buried) here for those who are still not convinced. |
784 | |
785 | =over 4 |
786 | |
787 | =item Another object system!?!? |
788 | |
789 | Yes, I know there has been an explosion recently of new ways to |
790 | build objects in Perl 5, most of them based on inside-out objects |
791 | and other such things. Moose is different because it is not a new |
792 | object system for Perl 5, but instead an extension of the existing |
793 | object system. |
794 | |
795 | Moose is built on top of L<Class::MOP>, which is a metaclass system |
796 | for Perl 5. This means that Moose not only makes building normal |
797 | Perl 5 objects better, but it also provides the power of metaclass |
798 | programming. |
799 | |
800 | =item Is this for real? Or is this just an experiment? |
801 | |
802 | Moose is I<based> on the prototypes and experiments I did for the Perl 6 |
803 | meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>. |
804 | |
805 | =item Is this ready for use in production? |
806 | |
807 | Yes, I believe that it is. |
808 | |
809 | Moose has been used successfully in production environemnts by several people |
810 | and companies (including the one I work for). There are Moose applications |
811 | which have been in production with little or no issue now for well over two years. |
812 | I consider it highly stable and we are commited to keeping it stable. |
813 | |
814 | Of course, in the end, you need to make this call yourself. If you have |
815 | any questions or concerns, please feel free to email me, or even the list |
816 | or just stop by #moose and ask away. |
817 | |
818 | =item Is Moose just Perl 6 in Perl 5? |
819 | |
820 | No. While Moose is very much inspired by Perl 6, it is not itself Perl 6. |
821 | Instead, it is an OO system for Perl 5. I built Moose because I was tired of |
822 | writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So |
823 | instead of switching to Ruby, I wrote Moose :) |
824 | |
825 | =item Wait, I<post> modern, I thought it was just I<modern>? |
826 | |
827 | So I was reading Larry Wall's talk from the 1999 Linux World entitled |
828 | "Perl, the first postmodern computer language" in which he talks about how |
829 | he picked the features for Perl because he thought they were cool and he |
830 | threw out the ones that he thought sucked. This got me thinking about how |
831 | we have done the same thing in Moose. For Moose, we have "borrowed" features |
832 | from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and |
833 | the bits we didn't like (cause they sucked) we tossed aside. So for this |
834 | reason (and a few others) I have re-dubbed Moose a I<postmodern> object system. |
835 | |
836 | Nuff Said. |
837 | |
838 | =back |
839 | |
5569c072 |
840 | =head1 ACKNOWLEDGEMENTS |
841 | |
842 | =over 4 |
843 | |
54c189df |
844 | =item I blame Sam Vilain for introducing me to the insanity that is meta-models. |
5569c072 |
845 | |
54c189df |
846 | =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6. |
5569c072 |
847 | |
26fbace8 |
848 | =item Without Yuval "nothingmuch" Kogman this module would not be possible, |
54c189df |
849 | and it certainly wouldn't have this name ;P |
5569c072 |
850 | |
26fbace8 |
851 | =item The basis of the TypeContraints module was Rob Kinyon's idea |
5569c072 |
852 | originally, I just ran with it. |
853 | |
638585e1 |
854 | =item Thanks to mst & chansen and the whole #moose posse for all the |
c84f324f |
855 | early ideas/feature-requests/encouragement/bug-finding. |
d46a48f3 |
856 | |
68efb014 |
857 | =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes. |
858 | |
5569c072 |
859 | =back |
860 | |
e90c03d0 |
861 | =head1 SEE ALSO |
862 | |
863 | =over 4 |
864 | |
c84f324f |
865 | =item L<http://www.iinteractive.com/moose> |
866 | |
867 | This is the official web home of Moose, it contains links to our public SVN repo |
26fbace8 |
868 | as well as links to a number of talks and articles on Moose and Moose related |
869 | technologies. |
c84f324f |
870 | |
196064ab |
871 | =item L<Moose::Cookbook> - How to cook a Moose |
872 | |
873 | =item The Moose is flying, a tutorial by Randal Schwartz |
874 | |
875 | Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html> |
876 | |
877 | Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html> |
878 | |
6ba6d68c |
879 | =item L<Class::MOP> documentation |
880 | |
881 | =item The #moose channel on irc.perl.org |
882 | |
e67a0fca |
883 | =item The Moose mailing list - moose@perl.org |
884 | |
9e0361e1 |
885 | =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose> |
c84f324f |
886 | |
12aed9a0 |
887 | =item Several Moose extension modules in the C<MooseX::> namespace. |
888 | |
889 | See L<http://search.cpan.org/search?query=MooseX::> for extensions. |
28669f89 |
890 | |
c84f324f |
891 | =back |
892 | |
004222dc |
893 | =head2 Books |
894 | |
895 | =over 4 |
896 | |
897 | =item The Art of the MetaObject Protocol |
898 | |
899 | I mention this in the L<Class::MOP> docs too, this book was critical in |
900 | the development of both modules and is highly recommended. |
901 | |
902 | =back |
903 | |
26fbace8 |
904 | =head2 Papers |
c84f324f |
905 | |
906 | =over 4 |
e90c03d0 |
907 | |
159da176 |
908 | =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf> |
909 | |
26fbace8 |
910 | This paper (suggested by lbr on #moose) was what lead to the implementation |
911 | of the C<super>/C<override> and C<inner>/C<augment> features. If you really |
1cd45431 |
912 | want to understand them, I suggest you read this. |
159da176 |
913 | |
e90c03d0 |
914 | =back |
915 | |
fcd84ca9 |
916 | =head1 BUGS |
917 | |
26fbace8 |
918 | All complex software has bugs lurking in it, and this module is no |
fcd84ca9 |
919 | exception. If you find a bug please either email me, or add the bug |
920 | to cpan-RT. |
921 | |
47b19570 |
922 | =head1 FEATURE REQUESTS |
923 | |
924 | We are very strict about what features we add to the Moose core, especially |
925 | the user-visible features. Instead we have made sure that the underlying |
926 | meta-system of Moose is as extensible as possible so that you can add your |
927 | own features easily. That said, occasionally there is a feature needed in the |
928 | meta-system to support your planned extension, in which case you should |
929 | either email the mailing list or join us on irc at #moose to discuss. |
930 | |
fcd84ca9 |
931 | =head1 AUTHOR |
932 | |
933 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
934 | |
9af1d28b |
935 | B<with contributions from:> |
db1ab48d |
936 | |
9af1d28b |
937 | Aankhen |
938 | |
939 | Adam (Alias) Kennedy |
940 | |
941 | Anders (Debolaz) Nor Berle |
942 | |
5868294f |
943 | Nathan (kolibre) Gray |
944 | |
9af1d28b |
945 | Christian (chansen) Hansen |
946 | |
e7f8d0c2 |
947 | Hans Dieter (confound) Pearcey |
948 | |
9af1d28b |
949 | Eric (ewilhelm) Wilhelm |
950 | |
951 | Guillermo (groditi) Roditi |
952 | |
953 | Jess (castaway) Robinson |
954 | |
955 | Matt (mst) Trout |
956 | |
957 | Robert (phaylon) Sedlacek |
958 | |
959 | Robert (rlb3) Boone |
960 | |
961 | Scott (konobi) McWhirter |
962 | |
f44ae52f |
963 | Shlomi (rindolf) Fish |
964 | |
9af1d28b |
965 | Yuval (nothingmuch) Kogman |
966 | |
cbe25729 |
967 | Chris (perigrin) Prather |
968 | |
68b6146c |
969 | Wallace (wreis) Reis |
970 | |
e46f5cc2 |
971 | Jonathan (jrockway) Rockway |
972 | |
3ccdc84a |
973 | Piotr (dexter) Roszatycki |
974 | |
26fbace8 |
975 | Sam (mugwump) Vilain |
f1917f58 |
976 | |
ac211120 |
977 | Shawn (sartak) Moore |
978 | |
9af1d28b |
979 | ... and many other #moose folks |
98aae381 |
980 | |
fcd84ca9 |
981 | =head1 COPYRIGHT AND LICENSE |
982 | |
778db3ac |
983 | Copyright 2006-2008 by Infinity Interactive, Inc. |
fcd84ca9 |
984 | |
985 | L<http://www.iinteractive.com> |
986 | |
987 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
988 | it under the same terms as Perl itself. |
fcd84ca9 |
989 | |
ddd0ec20 |
990 | =cut |