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 | |
cc841c0e |
129 | sub init_meta { |
085fba61 |
130 | # This used to be called as a function. This hack preserves |
131 | # backwards compatibility. |
132 | if ( $_[0] ne __PACKAGE__ ) { |
133 | return __PACKAGE__->init_meta( |
134 | for_class => $_[0], |
135 | base_class => $_[1], |
136 | metaclass => $_[2], |
137 | ); |
138 | } |
7c4676ef |
139 | |
0338a411 |
140 | shift; |
141 | my %args = @_; |
142 | |
143 | my $class = $args{for_class} |
085fba61 |
144 | or confess "Cannot call init_meta without specifying a for_class"; |
145 | my $base_class = $args{base_class} || 'Moose::Object'; |
146 | my $metaclass = $args{metaclass} || '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 | |
085fba61 |
186 | |
cc841c0e |
187 | return $meta; |
188 | } |
189 | |
085fba61 |
190 | # This may be used in some older MooseX extensions. |
191 | sub _get_caller { |
192 | goto &Moose::Exporter::_get_caller; |
193 | } |
194 | |
8ecb1fa0 |
195 | ## make 'em all immutable |
196 | |
197 | $_->meta->make_immutable( |
198 | inline_constructor => 0, |
77a18c28 |
199 | inline_accessors => 1, # these are Class::MOP accessors, so they need inlining |
9bcfbab1 |
200 | ) |
201 | for ( |
8ecb1fa0 |
202 | 'Moose::Meta::Attribute', |
203 | 'Moose::Meta::Class', |
204 | 'Moose::Meta::Instance', |
205 | |
206 | 'Moose::Meta::TypeConstraint', |
207 | 'Moose::Meta::TypeConstraint::Union', |
0fbd4b0a |
208 | 'Moose::Meta::TypeConstraint::Parameterized', |
8ecb1fa0 |
209 | 'Moose::Meta::TypeCoercion', |
210 | |
211 | 'Moose::Meta::Method', |
212 | 'Moose::Meta::Method::Accessor', |
213 | 'Moose::Meta::Method::Constructor', |
9bcfbab1 |
214 | 'Moose::Meta::Method::Destructor', |
8ecb1fa0 |
215 | 'Moose::Meta::Method::Overriden', |
d67145ed |
216 | |
217 | 'Moose::Meta::Role', |
9bcfbab1 |
218 | 'Moose::Meta::Role::Method', |
219 | 'Moose::Meta::Role::Method::Required', |
220 | ); |
8ecb1fa0 |
221 | |
fcd84ca9 |
222 | 1; |
223 | |
224 | __END__ |
225 | |
226 | =pod |
227 | |
228 | =head1 NAME |
229 | |
8bdc7f13 |
230 | Moose - A postmodern object system for Perl 5 |
fcd84ca9 |
231 | |
232 | =head1 SYNOPSIS |
e522431d |
233 | |
234 | package Point; |
1cd45431 |
235 | use Moose; # automatically turns on strict and warnings |
26fbace8 |
236 | |
43d599e5 |
237 | has 'x' => (is => 'rw', isa => 'Int'); |
238 | has 'y' => (is => 'rw', isa => 'Int'); |
26fbace8 |
239 | |
e522431d |
240 | sub clear { |
241 | my $self = shift; |
242 | $self->x(0); |
26fbace8 |
243 | $self->y(0); |
e522431d |
244 | } |
26fbace8 |
245 | |
e522431d |
246 | package Point3D; |
247 | use Moose; |
26fbace8 |
248 | |
e522431d |
249 | extends 'Point'; |
26fbace8 |
250 | |
43d599e5 |
251 | has 'z' => (is => 'rw', isa => 'Int'); |
26fbace8 |
252 | |
e522431d |
253 | after 'clear' => sub { |
254 | my $self = shift; |
43d599e5 |
255 | $self->z(0); |
26fbace8 |
256 | }; |
2c0cbef7 |
257 | |
fcd84ca9 |
258 | =head1 DESCRIPTION |
259 | |
26fbace8 |
260 | Moose is an extension of the Perl 5 object system. |
e522431d |
261 | |
9b9da6f1 |
262 | The main goal of Moose is to make Perl 5 Object Oriented programming |
263 | easier, more consistent and less tedious. With Moose you can to think |
264 | more about what you want to do and less about the mechanics of OOP. |
fcd84ca9 |
265 | |
9b9da6f1 |
266 | Additionally, Moose is built on top of L<Class::MOP>, which is a |
267 | metaclass system for Perl 5. This means that Moose not only makes |
268 | building normal Perl 5 objects better, but it provides the power of |
269 | metaclass programming as well. |
8bdc7f13 |
270 | |
28669f89 |
271 | =head2 Moose Extensions |
272 | |
12aed9a0 |
273 | The C<MooseX::> namespace is the official place to find Moose extensions. |
274 | These extensions can be found on the CPAN. The easiest way to find them |
275 | is to search for them (L<http://search.cpan.org/search?query=MooseX::>), |
276 | or to examine L<Task::Moose> which aims to keep an up-to-date, easily |
277 | installable list of Moose extensions. |
28669f89 |
278 | |
6ba6d68c |
279 | =head1 BUILDING CLASSES WITH MOOSE |
280 | |
68efb014 |
281 | Moose makes every attempt to provide as much convenience as possible during |
282 | class construction/definition, but still stay out of your way if you want it |
283 | to. Here are a few items to note when building classes with Moose. |
6ba6d68c |
284 | |
26fbace8 |
285 | Unless specified with C<extends>, any class which uses Moose will |
6ba6d68c |
286 | inherit from L<Moose::Object>. |
287 | |
1cd45431 |
288 | Moose will also manage all attributes (including inherited ones) that are |
289 | defined with C<has>. And (assuming you call C<new>, which is inherited from |
290 | L<Moose::Object>) this includes properly initializing all instance slots, |
291 | setting defaults where appropriate, and performing any type constraint checking |
292 | or coercion. |
6ba6d68c |
293 | |
004222dc |
294 | =head1 PROVIDED METHODS |
6ba6d68c |
295 | |
004222dc |
296 | Moose provides a number of methods to all your classes, mostly through the |
297 | inheritance of L<Moose::Object>. There is however, one exception. |
6ba6d68c |
298 | |
299 | =over 4 |
300 | |
301 | =item B<meta> |
302 | |
303 | This is a method which provides access to the current class's metaclass. |
304 | |
004222dc |
305 | =back |
306 | |
307 | =head1 EXPORTED FUNCTIONS |
308 | |
309 | Moose will export a number of functions into the class's namespace which |
310 | may then be used to set up the class. These functions all work directly |
311 | on the current class. |
312 | |
313 | =over 4 |
314 | |
6ba6d68c |
315 | =item B<extends (@superclasses)> |
316 | |
317 | This function will set the superclass(es) for the current class. |
318 | |
26fbace8 |
319 | This approach is recommended instead of C<use base>, because C<use base> |
320 | actually C<push>es onto the class's C<@ISA>, whereas C<extends> will |
321 | replace it. This is important to ensure that classes which do not have |
68efb014 |
322 | superclasses still properly inherit from L<Moose::Object>. |
6ba6d68c |
323 | |
43d599e5 |
324 | =item B<with (@roles)> |
e9ec68d6 |
325 | |
004222dc |
326 | This will apply a given set of C<@roles> to the local class. |
e9ec68d6 |
327 | |
cd7eeaf5 |
328 | =item B<has $name =E<gt> %options> |
6ba6d68c |
329 | |
26fbace8 |
330 | This will install an attribute of a given C<$name> into the current class. |
331 | The C<%options> are the same as those provided by |
332 | L<Class::MOP::Attribute>, in addition to the list below which are provided |
43d599e5 |
333 | by Moose (L<Moose::Meta::Attribute> to be more specific): |
6ba6d68c |
334 | |
335 | =over 4 |
336 | |
076c81ed |
337 | =item I<is =E<gt> 'rw'|'ro'> |
6ba6d68c |
338 | |
26fbace8 |
339 | The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read |
340 | only). These will create either a read/write accessor or a read-only |
6ba6d68c |
341 | accessor respectively, using the same name as the C<$name> of the attribute. |
342 | |
1cd45431 |
343 | If you need more control over how your accessors are named, you can use the |
344 | I<reader>, I<writer> and I<accessor> options inherited from |
004222dc |
345 | L<Class::MOP::Attribute>, however if you use those, you won't need the I<is> |
346 | option. |
6ba6d68c |
347 | |
076c81ed |
348 | =item I<isa =E<gt> $type_name> |
6ba6d68c |
349 | |
26fbace8 |
350 | The I<isa> option uses Moose's type constraint facilities to set up runtime |
351 | type checking for this attribute. Moose will perform the checks during class |
352 | construction, and within any accessors. The C<$type_name> argument must be a |
353 | string. The string may be either a class name or a type defined using |
9cca2e9e |
354 | Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints> |
c2a69ef1 |
355 | for information on how to define a new type, and how to retrieve type meta-data). |
6ba6d68c |
356 | |
daea75c9 |
357 | =item I<coerce =E<gt> (1|0)> |
358 | |
26fbace8 |
359 | This will attempt to use coercion with the supplied type constraint to change |
360 | the value passed into any accessors or constructors. You B<must> have supplied |
5cfe3805 |
361 | a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5> |
1cd45431 |
362 | for an example. |
daea75c9 |
363 | |
364 | =item I<does =E<gt> $role_name> |
365 | |
26fbace8 |
366 | This will accept the name of a role which the value stored in this attribute |
daea75c9 |
367 | is expected to have consumed. |
368 | |
369 | =item I<required =E<gt> (1|0)> |
370 | |
26fbace8 |
371 | This marks the attribute as being required. This means a I<defined> value must be |
372 | supplied during class construction, and the attribute may never be set to |
373 | C<undef> with an accessor. |
daea75c9 |
374 | |
375 | =item I<weak_ref =E<gt> (1|0)> |
376 | |
68efb014 |
377 | This will tell the class to store the value of this attribute as a weakened |
378 | reference. If an attribute is a weakened reference, it B<cannot> also be |
379 | coerced. |
daea75c9 |
380 | |
381 | =item I<lazy =E<gt> (1|0)> |
382 | |
26fbace8 |
383 | This will tell the class to not create this slot until absolutely necessary. |
daea75c9 |
384 | If an attribute is marked as lazy it B<must> have a default supplied. |
385 | |
9e93dd19 |
386 | =item I<auto_deref =E<gt> (1|0)> |
387 | |
26fbace8 |
388 | This tells the accessor whether to automatically dereference the value returned. |
1cd45431 |
389 | This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>. |
9e93dd19 |
390 | |
65e14c86 |
391 | =item I<trigger =E<gt> $code> |
392 | |
393 | The I<trigger> option is a CODE reference which will be called after the value of |
394 | the attribute is set. The CODE ref will be passed the instance itself, the |
395 | updated value and the attribute meta-object (this is for more advanced fiddling |
396 | and can typically be ignored). You B<cannot> have a trigger on a read-only |
397 | attribute. |
daea75c9 |
398 | |
c84f324f |
399 | =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE> |
2c0cbef7 |
400 | |
26fbace8 |
401 | The I<handles> option provides Moose classes with automated delegation features. |
402 | This is a pretty complex and powerful option. It accepts many different option |
403 | formats, each with its own benefits and drawbacks. |
38e3283b |
404 | |
1cd45431 |
405 | B<NOTE:> The class being delegated to does not need to be a Moose based class, |
406 | which is why this feature is especially useful when wrapping non-Moose classes. |
38e3283b |
407 | |
1cd45431 |
408 | All I<handles> option formats share the following traits: |
38e3283b |
409 | |
1cd45431 |
410 | You cannot override a locally defined method with a delegated method; an |
411 | exception will be thrown if you try. That is to say, if you define C<foo> in |
412 | your class, you cannot override it with a delegated C<foo>. This is almost never |
413 | something you would want to do, and if it is, you should do it by hand and not |
414 | use Moose. |
38e3283b |
415 | |
1cd45431 |
416 | You cannot override any of the methods found in Moose::Object, or the C<BUILD> |
417 | and C<DEMOLISH> methods. These will not throw an exception, but will silently |
418 | move on to the next method in the list. My reasoning for this is that you would |
419 | almost never want to do this, since it usually breaks your class. As with |
420 | overriding locally defined methods, if you do want to do this, you should do it |
421 | manually, not with Moose. |
38e3283b |
422 | |
f3c4e20e |
423 | You do not I<need> to have a reader (or accessor) for the attribute in order |
424 | to delegate to it. Moose will create a means of accessing the value for you, |
425 | however this will be several times B<less> efficient then if you had given |
426 | the attribute a reader (or accessor) to use. |
427 | |
38e3283b |
428 | Below is the documentation for each option format: |
429 | |
430 | =over 4 |
431 | |
432 | =item C<ARRAY> |
433 | |
26fbace8 |
434 | This is the most common usage for I<handles>. You basically pass a list of |
435 | method names to be delegated, and Moose will install a delegation method |
1cd45431 |
436 | for each one. |
38e3283b |
437 | |
438 | =item C<HASH> |
439 | |
26fbace8 |
440 | This is the second most common usage for I<handles>. Instead of a list of |
441 | method names, you pass a HASH ref where each key is the method name you |
442 | want installed locally, and its value is the name of the original method |
443 | in the class being delegated to. |
fd595040 |
444 | |
26fbace8 |
445 | This can be very useful for recursive classes like trees. Here is a |
5cfe3805 |
446 | quick example (soon to be expanded into a Moose::Cookbook recipe): |
38e3283b |
447 | |
1cd45431 |
448 | package Tree; |
38e3283b |
449 | use Moose; |
26fbace8 |
450 | |
38e3283b |
451 | has 'node' => (is => 'rw', isa => 'Any'); |
26fbace8 |
452 | |
38e3283b |
453 | has 'children' => ( |
454 | is => 'ro', |
455 | isa => 'ArrayRef', |
456 | default => sub { [] } |
457 | ); |
26fbace8 |
458 | |
38e3283b |
459 | has 'parent' => ( |
460 | is => 'rw', |
461 | isa => 'Tree', |
a4e516f6 |
462 | weak_ref => 1, |
38e3283b |
463 | handles => { |
464 | parent_node => 'node', |
26fbace8 |
465 | siblings => 'children', |
38e3283b |
466 | } |
467 | ); |
468 | |
1cd45431 |
469 | In this example, the Tree package gets C<parent_node> and C<siblings> methods, |
470 | which delegate to the C<node> and C<children> methods (respectively) of the Tree |
26fbace8 |
471 | instance stored in the C<parent> slot. |
38e3283b |
472 | |
473 | =item C<REGEXP> |
474 | |
26fbace8 |
475 | The regexp option works very similar to the ARRAY option, except that it builds |
476 | the list of methods for you. It starts by collecting all possible methods of the |
477 | class being delegated to, then filters that list using the regexp supplied here. |
38e3283b |
478 | |
26fbace8 |
479 | B<NOTE:> An I<isa> option is required when using the regexp option format. This |
480 | is so that we can determine (at compile time) the method list from the class. |
38e3283b |
481 | Without an I<isa> this is just not possible. |
482 | |
c84f324f |
483 | =item C<ROLE> |
484 | |
26fbace8 |
485 | With the role option, you specify the name of a role whose "interface" then |
486 | becomes the list of methods to handle. The "interface" can be defined as; the |
487 | methods of the role and any required methods of the role. It should be noted |
488 | that this does B<not> include any method modifiers or generated attribute |
c84f324f |
489 | methods (which is consistent with role composition). |
490 | |
38e3283b |
491 | =item C<CODE> |
492 | |
1cd45431 |
493 | This is the option to use when you really want to do something funky. You should |
494 | only use it if you really know what you are doing, as it involves manual |
495 | metaclass twiddling. |
38e3283b |
496 | |
1cd45431 |
497 | This takes a code reference, which should expect two arguments. The first is the |
498 | attribute meta-object this I<handles> is attached to. The second is the |
499 | metaclass of the class being delegated to. It expects you to return a hash (not |
26fbace8 |
500 | a HASH ref) of the methods you want mapped. |
38e3283b |
501 | |
502 | =back |
2c0cbef7 |
503 | |
004222dc |
504 | =item I<metaclass =E<gt> $metaclass_name> |
505 | |
506 | This tells the class to use a custom attribute metaclass for this particular |
507 | attribute. Custom attribute metaclasses are useful for extending the |
508 | capabilities of the I<has> keyword: they are the simplest way to extend the MOP, |
509 | but they are still a fairly advanced topic and too much to cover here, see |
5cfe3805 |
510 | L<Moose::Cookbook::Meta::Recipe1> for more information. |
004222dc |
511 | |
512 | The default behavior here is to just load C<$metaclass_name>; however, we also |
513 | have a way to alias to a shorter name. This will first look to see if |
514 | B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose |
515 | will then check to see if that has the method C<register_implementation>, which |
516 | should return the actual name of the custom attribute metaclass. If there is no |
517 | C<register_implementation> method, it will fall back to using |
518 | B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name. |
519 | |
520 | =item I<traits =E<gt> [ @role_names ]> |
521 | |
522 | This tells Moose to take the list of C<@role_names> and apply them to the |
523 | attribute meta-object. This is very similar to the I<metaclass> option, but |
524 | allows you to use more than one extension at a time. This too is an advanced |
525 | topic, we don't yet have a cookbook for it though. |
526 | |
527 | As with I<metaclass>, the default behavior is to just load C<$role_name>; however, |
528 | we also have a way to alias to a shorter name. This will first look to see if |
529 | B<Moose::Meta::Attribute::Custom::Trait::$role_name> exists. If it does, Moose |
530 | will then check to see if that has the method C<register_implementation>, which |
531 | should return the actual name of the custom attribute trait. If there is no |
532 | C<register_implementation> method, it will fall back to using |
533 | B<Moose::Meta::Attribute::Custom::Trait::$metaclass_name> as the trait name. |
534 | |
6ba6d68c |
535 | =back |
536 | |
cd7eeaf5 |
537 | =item B<has +$name =E<gt> %options> |
538 | |
26fbace8 |
539 | This is variation on the normal attibute creator C<has> which allows you to |
8d62bf6d |
540 | clone and extend an attribute from a superclass or from a role. Here is an |
541 | example of the superclass usage: |
cd7eeaf5 |
542 | |
543 | package Foo; |
544 | use Moose; |
26fbace8 |
545 | |
cd7eeaf5 |
546 | has 'message' => ( |
26fbace8 |
547 | is => 'rw', |
cd7eeaf5 |
548 | isa => 'Str', |
549 | default => 'Hello, I am a Foo' |
550 | ); |
26fbace8 |
551 | |
cd7eeaf5 |
552 | package My::Foo; |
553 | use Moose; |
26fbace8 |
554 | |
cd7eeaf5 |
555 | extends 'Foo'; |
26fbace8 |
556 | |
cd7eeaf5 |
557 | has '+message' => (default => 'Hello I am My::Foo'); |
558 | |
1cd45431 |
559 | What is happening here is that B<My::Foo> is cloning the C<message> attribute |
560 | from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt> |
561 | 'Str'> characteristics, but changing the value in C<default>. |
cd7eeaf5 |
562 | |
8d62bf6d |
563 | Here is another example, but within the context of a role: |
564 | |
565 | package Foo::Role; |
566 | use Moose::Role; |
986d175a |
567 | |
8d62bf6d |
568 | has 'message' => ( |
569 | is => 'rw', |
570 | isa => 'Str', |
571 | default => 'Hello, I am a Foo' |
572 | ); |
986d175a |
573 | |
8d62bf6d |
574 | package My::Foo; |
575 | use Moose; |
986d175a |
576 | |
8d62bf6d |
577 | with 'Foo::Role'; |
986d175a |
578 | |
8d62bf6d |
579 | has '+message' => (default => 'Hello I am My::Foo'); |
580 | |
581 | In this case, we are basically taking the attribute which the role supplied |
4032c9bb |
582 | and altering it within the bounds of this feature. |
8d62bf6d |
583 | |
4032c9bb |
584 | Aside from where the attributes come from (one from superclass, the other |
585 | from a role), this feature works exactly the same. This feature is restricted |
586 | somewhat, so as to try and force at least I<some> sanity into it. You are only |
587 | allowed to change the following attributes: |
cd7eeaf5 |
588 | |
589 | =over 4 |
590 | |
26fbace8 |
591 | =item I<default> |
cd7eeaf5 |
592 | |
593 | Change the default value of an attribute. |
594 | |
26fbace8 |
595 | =item I<coerce> |
cd7eeaf5 |
596 | |
597 | Change whether the attribute attempts to coerce a value passed to it. |
598 | |
26fbace8 |
599 | =item I<required> |
cd7eeaf5 |
600 | |
601 | Change if the attribute is required to have a value. |
602 | |
603 | =item I<documentation> |
604 | |
605 | Change the documentation string associated with the attribute. |
606 | |
83cc9094 |
607 | =item I<lazy> |
608 | |
609 | Change if the attribute lazily initializes the slot. |
610 | |
cd7eeaf5 |
611 | =item I<isa> |
612 | |
aed87761 |
613 | You I<are> allowed to change the type without restriction. |
614 | |
615 | It is recommended that you use this freedom with caution. We used to |
616 | only allow for extension only if the type was a subtype of the parent's |
617 | type, but we felt that was too restrictive and is better left as a |
618 | policy descision. |
cd7eeaf5 |
619 | |
83cc9094 |
620 | =item I<handles> |
621 | |
26fbace8 |
622 | You are allowed to B<add> a new C<handles> definition, but you are B<not> |
623 | allowed to I<change> one. |
83cc9094 |
624 | |
8d62bf6d |
625 | =item I<builder> |
626 | |
627 | You are allowed to B<add> a new C<builder> definition, but you are B<not> |
628 | allowed to I<change> one. |
629 | |
13284479 |
630 | =item I<metaclass> |
631 | |
632 | You are allowed to B<add> a new C<metaclass> definition, but you are |
633 | B<not> allowed to I<change> one. |
634 | |
635 | =item I<traits> |
636 | |
637 | You are allowed to B<add> additional traits to the C<traits> definition. |
638 | These traits will be composed into the attribute, but pre-existing traits |
639 | B<are not> overridden, or removed. |
640 | |
cd7eeaf5 |
641 | =back |
642 | |
076c81ed |
643 | =item B<before $name|@names =E<gt> sub { ... }> |
6ba6d68c |
644 | |
076c81ed |
645 | =item B<after $name|@names =E<gt> sub { ... }> |
6ba6d68c |
646 | |
076c81ed |
647 | =item B<around $name|@names =E<gt> sub { ... }> |
6ba6d68c |
648 | |
d8af92ae |
649 | This three items are syntactic sugar for the before, after, and around method |
650 | modifier features that L<Class::MOP> provides. More information on these may be |
651 | found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method |
652 | Modifiers"> for now. |
6ba6d68c |
653 | |
159da176 |
654 | =item B<super> |
655 | |
26fbace8 |
656 | The keyword C<super> is a no-op when called outside of an C<override> method. In |
657 | the context of an C<override> method, it will call the next most appropriate |
159da176 |
658 | superclass method with the same arguments as the original method. |
659 | |
660 | =item B<override ($name, &sub)> |
661 | |
26fbace8 |
662 | An C<override> method is a way of explicitly saying "I am overriding this |
663 | method from my superclass". You can call C<super> within this method, and |
664 | it will work as expected. The same thing I<can> be accomplished with a normal |
665 | method call and the C<SUPER::> pseudo-package; it is really your choice. |
159da176 |
666 | |
667 | =item B<inner> |
668 | |
26fbace8 |
669 | The keyword C<inner>, much like C<super>, is a no-op outside of the context of |
670 | an C<augment> method. You can think of C<inner> as being the inverse of |
68efb014 |
671 | C<super>; the details of how C<inner> and C<augment> work is best described in |
5cfe3805 |
672 | the L<Moose::Cookbook::Basics::Recipe6>. |
159da176 |
673 | |
674 | =item B<augment ($name, &sub)> |
675 | |
26fbace8 |
676 | An C<augment> method, is a way of explicitly saying "I am augmenting this |
677 | method from my superclass". Once again, the details of how C<inner> and |
5cfe3805 |
678 | C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>. |
159da176 |
679 | |
6ba6d68c |
680 | =item B<confess> |
681 | |
68efb014 |
682 | This is the C<Carp::confess> function, and exported here because I use it |
004222dc |
683 | all the time. |
6ba6d68c |
684 | |
685 | =item B<blessed> |
686 | |
1cd45431 |
687 | This is the C<Scalar::Util::blessed> function, it is exported here because I |
26fbace8 |
688 | use it all the time. It is highly recommended that this is used instead of |
6ba6d68c |
689 | C<ref> anywhere you need to test for an object's class name. |
690 | |
691 | =back |
692 | |
1cd45431 |
693 | =head1 UNIMPORTING FUNCTIONS |
31f8ec72 |
694 | |
695 | =head2 B<unimport> |
696 | |
1cd45431 |
697 | Moose offers a way to remove the keywords it exports, through the C<unimport> |
31f8ec72 |
698 | method. You simply have to say C<no Moose> at the bottom of your code for this |
699 | to work. Here is an example: |
700 | |
701 | package Person; |
702 | use Moose; |
703 | |
704 | has 'first_name' => (is => 'rw', isa => 'Str'); |
705 | has 'last_name' => (is => 'rw', isa => 'Str'); |
26fbace8 |
706 | |
707 | sub full_name { |
31f8ec72 |
708 | my $self = shift; |
26fbace8 |
709 | $self->first_name . ' ' . $self->last_name |
31f8ec72 |
710 | } |
26fbace8 |
711 | |
712 | no Moose; # keywords are removed from the Person package |
31f8ec72 |
713 | |
9bcfbab1 |
714 | =head1 EXTENDING AND EMBEDDING MOOSE |
715 | |
554b7648 |
716 | Moose also offers some options for extending or embedding it into your |
717 | own framework. There are several things you might want to do as part |
718 | of such a framework. First, you probably want to export Moose's sugar |
719 | functions (C<has>, C<extends>, etc) for users of the |
720 | framework. Second, you may want to provide additional sugar of your |
721 | own. Third, you may want to provide your own object base class instead |
722 | of L<Moose::Object>, and/or your own metaclass class instead of |
723 | L<Moose::Meta::Class>. |
724 | |
725 | The exporting needs can be asily satisfied by using |
726 | L<Moose::Exporter>, which is what C<Moose.pm> itself uses for |
727 | exporting. L<Moose::Exporter> lets you "export like Moose". |
728 | |
729 | If you define an C<init_meta> method in a module that uses |
730 | L<Moose::Exporter>, then this method will be called I<before> |
731 | C<Moose.pm>'s own C<init_meta>. This gives you a chance to provide an |
732 | alternate object base class or metaclass class. |
733 | |
734 | Here is a simple example: |
9bcfbab1 |
735 | |
736 | package MyFramework; |
9bcfbab1 |
737 | |
554b7648 |
738 | use strict; |
739 | use warnings; |
9bcfbab1 |
740 | |
554b7648 |
741 | use Moose (); # no need to get Moose's exports |
742 | use Moose::Exporter; |
9bcfbab1 |
743 | |
554b7648 |
744 | Moose::Exporter->build_import_methods( also => 'Moose' ); |
26fbace8 |
745 | |
554b7648 |
746 | sub init_meta { |
747 | shift; |
748 | return Moose->init_meta( @_, base_class => 'MyFramework::Base' ); |
9bcfbab1 |
749 | } |
26fbace8 |
750 | |
554b7648 |
751 | In this example, any class that includes C<use MyFramework> will get |
752 | all of C<Moose.pm>'s sugar functions, and will have their superclass |
753 | set to C<MyFramework::Base>. |
9bcfbab1 |
754 | |
554b7648 |
755 | Additionally, that class can include C<no MyFramework> to unimport |
756 | |
757 | =head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >> |
9bcfbab1 |
758 | |
554b7648 |
759 | The C<init_meta> method sets up the metaclass object for the class |
760 | specified by C<for_class>. It also injects a a C<meta> accessor into |
761 | the class so you can get at this object. It also sets the class's |
762 | superclass to C<base_class>, with L<Moose::Object> as the default. |
9bcfbab1 |
763 | |
554b7648 |
764 | You can specify an alternate metaclass with the C<metaclass> parameter. |
26fbace8 |
765 | |
80837fe1 |
766 | For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>. |
767 | |
554b7648 |
768 | This method used to be documented as a function which accepted |
769 | positional parameters. This calling style will still work for |
770 | backwards compatibility. |
771 | |
772 | =head2 B<import> |
773 | |
774 | Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}> |
775 | and C<{into_level =E<gt> 1}>. |
776 | |
777 | B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter> |
778 | instead, which lets you stack multiple C<Moose.pm>-alike modules |
779 | sanely. It handles getting the exported functions into the right place |
780 | for you. |
781 | |
05d9eaf6 |
782 | =head1 CAVEATS |
783 | |
784 | =over 4 |
785 | |
786 | =item * |
787 | |
1cd45431 |
788 | It should be noted that C<super> and C<inner> B<cannot> be used in the same |
789 | method. However, they may be combined within the same class hierarchy; see |
790 | F<t/014_override_augment_inner_super.t> for an example. |
05d9eaf6 |
791 | |
26fbace8 |
792 | The reason for this is that C<super> is only valid within a method |
793 | with the C<override> modifier, and C<inner> will never be valid within an |
794 | C<override> method. In fact, C<augment> will skip over any C<override> methods |
68efb014 |
795 | when searching for its appropriate C<inner>. |
05d9eaf6 |
796 | |
1cd45431 |
797 | This might seem like a restriction, but I am of the opinion that keeping these |
798 | two features separate (yet interoperable) actually makes them easy to use, since |
799 | their behavior is then easier to predict. Time will tell whether I am right or |
c84f324f |
800 | not (UPDATE: so far so good). |
05d9eaf6 |
801 | |
004222dc |
802 | =item * |
803 | |
804 | It is important to note that we currently have no simple way of combining |
805 | multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above), |
806 | and that in many cases they will conflict with one another. We are working on |
807 | developing a way around this issue, but in the meantime, you have been warned. |
808 | |
05d9eaf6 |
809 | =back |
810 | |
9b9da6f1 |
811 | =head1 JUSTIFICATION |
812 | |
813 | In case you are still asking yourself "Why do I need this?", then this |
814 | section is for you. This used to be part of the main DESCRIPTION, but |
815 | I think Moose no longer actually needs justification, so it is included |
816 | (read: buried) here for those who are still not convinced. |
817 | |
818 | =over 4 |
819 | |
820 | =item Another object system!?!? |
821 | |
822 | Yes, I know there has been an explosion recently of new ways to |
823 | build objects in Perl 5, most of them based on inside-out objects |
824 | and other such things. Moose is different because it is not a new |
825 | object system for Perl 5, but instead an extension of the existing |
826 | object system. |
827 | |
828 | Moose is built on top of L<Class::MOP>, which is a metaclass system |
829 | for Perl 5. This means that Moose not only makes building normal |
830 | Perl 5 objects better, but it also provides the power of metaclass |
831 | programming. |
832 | |
833 | =item Is this for real? Or is this just an experiment? |
834 | |
835 | Moose is I<based> on the prototypes and experiments I did for the Perl 6 |
836 | meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>. |
837 | |
838 | =item Is this ready for use in production? |
839 | |
840 | Yes, I believe that it is. |
841 | |
842 | Moose has been used successfully in production environemnts by several people |
843 | and companies (including the one I work for). There are Moose applications |
844 | which have been in production with little or no issue now for well over two years. |
845 | I consider it highly stable and we are commited to keeping it stable. |
846 | |
847 | Of course, in the end, you need to make this call yourself. If you have |
848 | any questions or concerns, please feel free to email me, or even the list |
849 | or just stop by #moose and ask away. |
850 | |
851 | =item Is Moose just Perl 6 in Perl 5? |
852 | |
853 | No. While Moose is very much inspired by Perl 6, it is not itself Perl 6. |
854 | Instead, it is an OO system for Perl 5. I built Moose because I was tired of |
855 | writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So |
856 | instead of switching to Ruby, I wrote Moose :) |
857 | |
858 | =item Wait, I<post> modern, I thought it was just I<modern>? |
859 | |
860 | So I was reading Larry Wall's talk from the 1999 Linux World entitled |
861 | "Perl, the first postmodern computer language" in which he talks about how |
862 | he picked the features for Perl because he thought they were cool and he |
863 | threw out the ones that he thought sucked. This got me thinking about how |
864 | we have done the same thing in Moose. For Moose, we have "borrowed" features |
865 | from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and |
866 | the bits we didn't like (cause they sucked) we tossed aside. So for this |
867 | reason (and a few others) I have re-dubbed Moose a I<postmodern> object system. |
868 | |
869 | Nuff Said. |
870 | |
871 | =back |
872 | |
5569c072 |
873 | =head1 ACKNOWLEDGEMENTS |
874 | |
875 | =over 4 |
876 | |
54c189df |
877 | =item I blame Sam Vilain for introducing me to the insanity that is meta-models. |
5569c072 |
878 | |
54c189df |
879 | =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6. |
5569c072 |
880 | |
26fbace8 |
881 | =item Without Yuval "nothingmuch" Kogman this module would not be possible, |
54c189df |
882 | and it certainly wouldn't have this name ;P |
5569c072 |
883 | |
26fbace8 |
884 | =item The basis of the TypeContraints module was Rob Kinyon's idea |
5569c072 |
885 | originally, I just ran with it. |
886 | |
638585e1 |
887 | =item Thanks to mst & chansen and the whole #moose posse for all the |
c84f324f |
888 | early ideas/feature-requests/encouragement/bug-finding. |
d46a48f3 |
889 | |
68efb014 |
890 | =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes. |
891 | |
5569c072 |
892 | =back |
893 | |
e90c03d0 |
894 | =head1 SEE ALSO |
895 | |
896 | =over 4 |
897 | |
c84f324f |
898 | =item L<http://www.iinteractive.com/moose> |
899 | |
900 | This is the official web home of Moose, it contains links to our public SVN repo |
26fbace8 |
901 | as well as links to a number of talks and articles on Moose and Moose related |
902 | technologies. |
c84f324f |
903 | |
196064ab |
904 | =item L<Moose::Cookbook> - How to cook a Moose |
905 | |
906 | =item The Moose is flying, a tutorial by Randal Schwartz |
907 | |
908 | Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html> |
909 | |
910 | Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html> |
911 | |
6ba6d68c |
912 | =item L<Class::MOP> documentation |
913 | |
914 | =item The #moose channel on irc.perl.org |
915 | |
e67a0fca |
916 | =item The Moose mailing list - moose@perl.org |
917 | |
9e0361e1 |
918 | =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose> |
c84f324f |
919 | |
12aed9a0 |
920 | =item Several Moose extension modules in the C<MooseX::> namespace. |
921 | |
922 | See L<http://search.cpan.org/search?query=MooseX::> for extensions. |
28669f89 |
923 | |
c84f324f |
924 | =back |
925 | |
004222dc |
926 | =head2 Books |
927 | |
928 | =over 4 |
929 | |
930 | =item The Art of the MetaObject Protocol |
931 | |
932 | I mention this in the L<Class::MOP> docs too, this book was critical in |
933 | the development of both modules and is highly recommended. |
934 | |
935 | =back |
936 | |
26fbace8 |
937 | =head2 Papers |
c84f324f |
938 | |
939 | =over 4 |
e90c03d0 |
940 | |
159da176 |
941 | =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf> |
942 | |
26fbace8 |
943 | This paper (suggested by lbr on #moose) was what lead to the implementation |
944 | of the C<super>/C<override> and C<inner>/C<augment> features. If you really |
1cd45431 |
945 | want to understand them, I suggest you read this. |
159da176 |
946 | |
e90c03d0 |
947 | =back |
948 | |
fcd84ca9 |
949 | =head1 BUGS |
950 | |
26fbace8 |
951 | All complex software has bugs lurking in it, and this module is no |
fcd84ca9 |
952 | exception. If you find a bug please either email me, or add the bug |
953 | to cpan-RT. |
954 | |
47b19570 |
955 | =head1 FEATURE REQUESTS |
956 | |
957 | We are very strict about what features we add to the Moose core, especially |
958 | the user-visible features. Instead we have made sure that the underlying |
959 | meta-system of Moose is as extensible as possible so that you can add your |
960 | own features easily. That said, occasionally there is a feature needed in the |
961 | meta-system to support your planned extension, in which case you should |
962 | either email the mailing list or join us on irc at #moose to discuss. |
963 | |
fcd84ca9 |
964 | =head1 AUTHOR |
965 | |
966 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
967 | |
9af1d28b |
968 | B<with contributions from:> |
db1ab48d |
969 | |
9af1d28b |
970 | Aankhen |
971 | |
972 | Adam (Alias) Kennedy |
973 | |
974 | Anders (Debolaz) Nor Berle |
975 | |
5868294f |
976 | Nathan (kolibre) Gray |
977 | |
9af1d28b |
978 | Christian (chansen) Hansen |
979 | |
e7f8d0c2 |
980 | Hans Dieter (confound) Pearcey |
981 | |
9af1d28b |
982 | Eric (ewilhelm) Wilhelm |
983 | |
984 | Guillermo (groditi) Roditi |
985 | |
986 | Jess (castaway) Robinson |
987 | |
988 | Matt (mst) Trout |
989 | |
990 | Robert (phaylon) Sedlacek |
991 | |
992 | Robert (rlb3) Boone |
993 | |
994 | Scott (konobi) McWhirter |
995 | |
f44ae52f |
996 | Shlomi (rindolf) Fish |
997 | |
9af1d28b |
998 | Yuval (nothingmuch) Kogman |
999 | |
cbe25729 |
1000 | Chris (perigrin) Prather |
1001 | |
68b6146c |
1002 | Wallace (wreis) Reis |
1003 | |
e46f5cc2 |
1004 | Jonathan (jrockway) Rockway |
1005 | |
3ccdc84a |
1006 | Piotr (dexter) Roszatycki |
1007 | |
26fbace8 |
1008 | Sam (mugwump) Vilain |
f1917f58 |
1009 | |
ac211120 |
1010 | Shawn (sartak) Moore |
1011 | |
9af1d28b |
1012 | ... and many other #moose folks |
98aae381 |
1013 | |
fcd84ca9 |
1014 | =head1 COPYRIGHT AND LICENSE |
1015 | |
778db3ac |
1016 | Copyright 2006-2008 by Infinity Interactive, Inc. |
fcd84ca9 |
1017 | |
1018 | L<http://www.iinteractive.com> |
1019 | |
1020 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
1021 | it under the same terms as Perl itself. |
fcd84ca9 |
1022 | |
ddd0ec20 |
1023 | =cut |