Commit | Line | Data |
fcd84ca9 |
1 | |
2 | package Moose; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
cbd141ca |
7 | our $VERSION = '0.43'; |
d44714be |
8 | our $AUTHORITY = 'cpan:STEVAN'; |
fcd84ca9 |
9 | |
cc65ead0 |
10 | use Scalar::Util 'blessed', 'reftype'; |
c0b37457 |
11 | use Carp 'confess', 'croak', 'cluck'; |
3796382a |
12 | use Sub::Name 'subname'; |
fcd84ca9 |
13 | |
2d562421 |
14 | use Sub::Exporter; |
7f18097c |
15 | |
3f9e4b0a |
16 | use MRO::Compat; |
c2922d69 |
17 | use Class::MOP; |
ef1d5f4b |
18 | |
c0e30cf5 |
19 | use Moose::Meta::Class; |
7415b2cb |
20 | use Moose::Meta::TypeConstraint; |
7c13858b |
21 | use Moose::Meta::TypeCoercion; |
78cd1d3b |
22 | use Moose::Meta::Attribute; |
ddd0ec20 |
23 | use Moose::Meta::Instance; |
c0e30cf5 |
24 | |
d67145ed |
25 | use Moose::Meta::Role; |
26 | |
fcd84ca9 |
27 | use Moose::Object; |
7415b2cb |
28 | use Moose::Util::TypeConstraints; |
d7d8a8c7 |
29 | use Moose::Util (); |
a15dff8d |
30 | |
a3c7e2fe |
31 | { |
be33e4f3 |
32 | my $CALLER; |
9bcfbab1 |
33 | |
34 | sub init_meta { |
35 | my ( $class, $base_class, $metaclass ) = @_; |
688fcdda |
36 | $base_class = 'Moose::Object' unless defined $base_class; |
37 | $metaclass = 'Moose::Meta::Class' unless defined $metaclass; |
9bcfbab1 |
38 | |
39 | confess |
97e11ef5 |
40 | "The Metaclass $metaclass must be a subclass of Moose::Meta::Class." |
41 | unless $metaclass->isa('Moose::Meta::Class'); |
a3c7e2fe |
42 | |
a3c7e2fe |
43 | # make a subtype for each Moose class |
3fef8ce8 |
44 | class_type($class) |
45 | unless find_type_constraint($class); |
a3c7e2fe |
46 | |
47 | my $meta; |
9bcfbab1 |
48 | if ( $class->can('meta') ) { |
fcec2383 |
49 | # NOTE: |
9bcfbab1 |
50 | # this is the case where the metaclass pragma |
51 | # was used before the 'use Moose' statement to |
fcec2383 |
52 | # override a specific class |
a3c7e2fe |
53 | $meta = $class->meta(); |
9bcfbab1 |
54 | ( blessed($meta) && $meta->isa('Moose::Meta::Class') ) |
1edfdf1c |
55 | || confess "You already have a &meta function, but it does not return a Moose::Meta::Class"; |
a3c7e2fe |
56 | } |
57 | else { |
fcec2383 |
58 | # NOTE: |
9bcfbab1 |
59 | # this is broken currently, we actually need |
60 | # to allow the possiblity of an inherited |
61 | # meta, which will not be visible until the |
62 | # user 'extends' first. This needs to have |
63 | # more intelligence to it |
64 | $meta = $metaclass->initialize($class); |
65 | $meta->add_method( |
66 | 'meta' => sub { |
9bcfbab1 |
67 | # re-initialize so it inherits properly |
68 | $metaclass->initialize( blessed( $_[0] ) || $_[0] ); |
69 | } |
70 | ); |
a3c7e2fe |
71 | } |
72 | |
73 | # make sure they inherit from Moose::Object |
72bbc189 |
74 | $meta->superclasses($base_class) |
9bcfbab1 |
75 | unless $meta->superclasses(); |
688fcdda |
76 | |
77 | return $meta; |
a3c7e2fe |
78 | } |
79 | |
80 | my %exports = ( |
81 | extends => sub { |
be33e4f3 |
82 | my $class = $CALLER; |
68117c45 |
83 | return subname 'Moose::extends' => sub (@) { |
84 | confess "Must derive at least one class" unless @_; |
9c10b5ad |
85 | |
86 | my @supers = @_; |
87 | foreach my $super (@supers) { |
88 | Class::MOP::load_class($super); |
89 | } |
9bcfbab1 |
90 | |
91 | # this checks the metaclass to make sure |
92 | # it is correct, sometimes it can get out |
1341f10c |
93 | # of sync when the classes are being built |
9c10b5ad |
94 | my $meta = $class->meta->_fix_metaclass_incompatability(@supers); |
95 | $meta->superclasses(@supers); |
a3c7e2fe |
96 | }; |
97 | }, |
98 | with => sub { |
be33e4f3 |
99 | my $class = $CALLER; |
68117c45 |
100 | return subname 'Moose::with' => sub (@) { |
d7d8a8c7 |
101 | Moose::Util::apply_all_roles($class->meta, @_) |
a3c7e2fe |
102 | }; |
103 | }, |
104 | has => sub { |
be33e4f3 |
105 | my $class = $CALLER; |
2c0cbef7 |
106 | return subname 'Moose::has' => sub ($;%) { |
a28fe77b |
107 | my $name = shift; |
547dda77 |
108 | croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1; |
a28fe77b |
109 | my %options = @_; |
9bcfbab1 |
110 | my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ]; |
d7d8a8c7 |
111 | $class->meta->add_attribute( $_, %options ) for @$attrs; |
a3c7e2fe |
112 | }; |
113 | }, |
114 | before => sub { |
be33e4f3 |
115 | my $class = $CALLER; |
2c0cbef7 |
116 | return subname 'Moose::before' => sub (@&) { |
a3c7e2fe |
117 | my $code = pop @_; |
be33e4f3 |
118 | my $meta = $class->meta; |
9bcfbab1 |
119 | $meta->add_before_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
120 | }; |
121 | }, |
122 | after => sub { |
be33e4f3 |
123 | my $class = $CALLER; |
2c0cbef7 |
124 | return subname 'Moose::after' => sub (@&) { |
a3c7e2fe |
125 | my $code = pop @_; |
be33e4f3 |
126 | my $meta = $class->meta; |
9bcfbab1 |
127 | $meta->add_after_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
128 | }; |
129 | }, |
130 | around => sub { |
9bcfbab1 |
131 | my $class = $CALLER; |
2c0cbef7 |
132 | return subname 'Moose::around' => sub (@&) { |
a3c7e2fe |
133 | my $code = pop @_; |
be33e4f3 |
134 | my $meta = $class->meta; |
9bcfbab1 |
135 | $meta->add_around_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
136 | }; |
137 | }, |
138 | super => sub { |
3f9e4b0a |
139 | # FIXME can be made into goto, might break caller() for existing code |
140 | return subname 'Moose::super' => sub { return unless our $SUPER_BODY; $SUPER_BODY->(our @SUPER_ARGS) } |
a3c7e2fe |
141 | }, |
3f9e4b0a |
142 | #next => sub { |
143 | # return subname 'Moose::next' => sub { @_ = our @SUPER_ARGS; goto \&next::method }; |
144 | #}, |
a3c7e2fe |
145 | override => sub { |
be33e4f3 |
146 | my $class = $CALLER; |
2c0cbef7 |
147 | return subname 'Moose::override' => sub ($&) { |
9bcfbab1 |
148 | my ( $name, $method ) = @_; |
149 | $class->meta->add_override_method_modifier( $name => $method ); |
a3c7e2fe |
150 | }; |
151 | }, |
152 | inner => sub { |
3f9e4b0a |
153 | return subname 'Moose::inner' => sub { |
154 | my $pkg = caller(); |
155 | our ( %INNER_BODY, %INNER_ARGS ); |
156 | |
157 | if ( my $body = $INNER_BODY{$pkg} ) { |
158 | my @args = @{ $INNER_ARGS{$pkg} }; |
159 | local $INNER_ARGS{$pkg}; |
160 | local $INNER_BODY{$pkg}; |
161 | return $body->(@args); |
162 | } else { |
163 | return; |
164 | } |
165 | }; |
a3c7e2fe |
166 | }, |
167 | augment => sub { |
be33e4f3 |
168 | my $class = $CALLER; |
2c0cbef7 |
169 | return subname 'Moose::augment' => sub (@&) { |
9bcfbab1 |
170 | my ( $name, $method ) = @_; |
171 | $class->meta->add_augment_method_modifier( $name => $method ); |
a3c7e2fe |
172 | }; |
173 | }, |
2a5e59d0 |
174 | make_immutable => sub { |
175 | my $class = $CALLER; |
176 | return subname 'Moose::make_immutable' => sub { |
c0b37457 |
177 | cluck "The make_immutable keyword has been deprecated, " . |
178 | "please go back to __PACKAGE__->meta->make_immutable\n"; |
e902b1a5 |
179 | $class->meta->make_immutable(@_); |
2a5e59d0 |
180 | }; |
181 | }, |
a3c7e2fe |
182 | confess => sub { |
183 | return \&Carp::confess; |
184 | }, |
185 | blessed => sub { |
186 | return \&Scalar::Util::blessed; |
66bcefc1 |
187 | }, |
a3c7e2fe |
188 | ); |
3d544ed5 |
189 | |
9bcfbab1 |
190 | my $exporter = Sub::Exporter::build_exporter( |
191 | { |
192 | exports => \%exports, |
193 | groups => { default => [':all'] } |
a3c7e2fe |
194 | } |
9bcfbab1 |
195 | ); |
196 | |
c92c1205 |
197 | # 1 extra level because it's called by import so there's a layer of indirection |
198 | sub _get_caller{ |
199 | my $offset = 1; |
26fbace8 |
200 | return |
c92c1205 |
201 | ref $_[1] && defined $_[1]->{into} |
202 | ? $_[1]->{into} |
203 | : ref $_[1] && defined $_[1]->{into_level} |
204 | ? caller($offset + $_[1]->{into_level}) |
205 | : caller($offset); |
206 | } |
5bee491d |
207 | |
208 | sub import { |
c92c1205 |
209 | $CALLER = _get_caller(@_); |
26fbace8 |
210 | |
86dd5d11 |
211 | # this works because both pragmas set $^H (see perldoc perlvar) |
212 | # which affects the current compilation - i.e. the file who use'd |
213 | # us - which is why we don't need to do anything special to make |
214 | # it affect that file rather than this one (which is already compiled) |
215 | |
c235cd98 |
216 | strict->import; |
9bcfbab1 |
217 | warnings->import; |
a3c7e2fe |
218 | |
219 | # we should never export to main |
220 | return if $CALLER eq 'main'; |
9bcfbab1 |
221 | |
222 | init_meta( $CALLER, 'Moose::Object' ); |
223 | |
a3c7e2fe |
224 | goto $exporter; |
fcb7afc2 |
225 | } |
9bcfbab1 |
226 | |
31f8ec72 |
227 | sub unimport { |
9bcfbab1 |
228 | no strict 'refs'; |
c92c1205 |
229 | my $class = _get_caller(@_); |
9bcfbab1 |
230 | |
31f8ec72 |
231 | # loop through the exports ... |
9bcfbab1 |
232 | foreach my $name ( keys %exports ) { |
233 | |
31f8ec72 |
234 | # if we find one ... |
9bcfbab1 |
235 | if ( defined &{ $class . '::' . $name } ) { |
236 | my $keyword = \&{ $class . '::' . $name }; |
237 | |
31f8ec72 |
238 | # make sure it is from Moose |
53dd42d8 |
239 | my ($pkg_name) = Class::MOP::get_code_info($keyword); |
31f8ec72 |
240 | next if $@; |
241 | next if $pkg_name ne 'Moose'; |
9bcfbab1 |
242 | |
31f8ec72 |
243 | # and if it is from Moose then undef the slot |
9bcfbab1 |
244 | delete ${ $class . '::' }{$name}; |
31f8ec72 |
245 | } |
246 | } |
247 | } |
9bcfbab1 |
248 | |
fcd84ca9 |
249 | } |
250 | |
8ecb1fa0 |
251 | ## make 'em all immutable |
252 | |
253 | $_->meta->make_immutable( |
254 | inline_constructor => 0, |
77a18c28 |
255 | inline_accessors => 1, # these are Class::MOP accessors, so they need inlining |
9bcfbab1 |
256 | ) |
257 | for ( |
8ecb1fa0 |
258 | 'Moose::Meta::Attribute', |
259 | 'Moose::Meta::Class', |
260 | 'Moose::Meta::Instance', |
261 | |
262 | 'Moose::Meta::TypeConstraint', |
263 | 'Moose::Meta::TypeConstraint::Union', |
0fbd4b0a |
264 | 'Moose::Meta::TypeConstraint::Parameterized', |
8ecb1fa0 |
265 | 'Moose::Meta::TypeCoercion', |
266 | |
267 | 'Moose::Meta::Method', |
268 | 'Moose::Meta::Method::Accessor', |
269 | 'Moose::Meta::Method::Constructor', |
9bcfbab1 |
270 | 'Moose::Meta::Method::Destructor', |
8ecb1fa0 |
271 | 'Moose::Meta::Method::Overriden', |
d67145ed |
272 | |
273 | 'Moose::Meta::Role', |
9bcfbab1 |
274 | 'Moose::Meta::Role::Method', |
275 | 'Moose::Meta::Role::Method::Required', |
276 | ); |
8ecb1fa0 |
277 | |
fcd84ca9 |
278 | 1; |
279 | |
280 | __END__ |
281 | |
282 | =pod |
283 | |
284 | =head1 NAME |
285 | |
8bdc7f13 |
286 | Moose - A postmodern object system for Perl 5 |
fcd84ca9 |
287 | |
288 | =head1 SYNOPSIS |
e522431d |
289 | |
290 | package Point; |
1cd45431 |
291 | use Moose; # automatically turns on strict and warnings |
26fbace8 |
292 | |
43d599e5 |
293 | has 'x' => (is => 'rw', isa => 'Int'); |
294 | has 'y' => (is => 'rw', isa => 'Int'); |
26fbace8 |
295 | |
e522431d |
296 | sub clear { |
297 | my $self = shift; |
298 | $self->x(0); |
26fbace8 |
299 | $self->y(0); |
e522431d |
300 | } |
26fbace8 |
301 | |
e522431d |
302 | package Point3D; |
303 | use Moose; |
26fbace8 |
304 | |
e522431d |
305 | extends 'Point'; |
26fbace8 |
306 | |
43d599e5 |
307 | has 'z' => (is => 'rw', isa => 'Int'); |
26fbace8 |
308 | |
e522431d |
309 | after 'clear' => sub { |
310 | my $self = shift; |
43d599e5 |
311 | $self->z(0); |
26fbace8 |
312 | }; |
2c0cbef7 |
313 | |
fcd84ca9 |
314 | =head1 DESCRIPTION |
315 | |
26fbace8 |
316 | Moose is an extension of the Perl 5 object system. |
e522431d |
317 | |
318 | =head2 Another object system!?!? |
fcd84ca9 |
319 | |
26fbace8 |
320 | Yes, I know there has been an explosion recently of new ways to |
68efb014 |
321 | build object's in Perl 5, most of them based on inside-out objects |
26fbace8 |
322 | and other such things. Moose is different because it is not a new |
323 | object system for Perl 5, but instead an extension of the existing |
e522431d |
324 | object system. |
3c7278fb |
325 | |
26fbace8 |
326 | Moose is built on top of L<Class::MOP>, which is a metaclass system |
327 | for Perl 5. This means that Moose not only makes building normal |
328 | Perl 5 objects better, but it also provides the power of metaclass |
505c6fac |
329 | programming. |
e522431d |
330 | |
734d1752 |
331 | =head2 Is this for real? Or is this just an experiment? |
e522431d |
332 | |
2c0cbef7 |
333 | Moose is I<based> on the prototypes and experiments I did for the Perl 6 |
26fbace8 |
334 | meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>. |
734d1752 |
335 | |
26fbace8 |
336 | =head2 Is this ready for use in production? |
d44714be |
337 | |
26fbace8 |
338 | Yes, I believe that it is. |
734d1752 |
339 | |
26fbace8 |
340 | Moose has been used successfully in production environemnts by several people |
341 | and companies (including the one I work for). There are Moose applications |
8bdc7f13 |
342 | which have been in production with little or no issue now for well over a year. |
26fbace8 |
343 | I consider it highly stable and we are commited to keeping it stable. |
e522431d |
344 | |
26fbace8 |
345 | Of course, in the end, you need to make this call yourself. If you have |
346 | any questions or concerns, please feel free to email me, or even the list |
d44714be |
347 | or just stop by #moose and ask away. |
348 | |
43d599e5 |
349 | =head2 Is Moose just Perl 6 in Perl 5? |
e522431d |
350 | |
68efb014 |
351 | No. While Moose is very much inspired by Perl 6, it is not itself Perl 6. |
1cd45431 |
352 | Instead, it is an OO system for Perl 5. I built Moose because I was tired of |
68efb014 |
353 | writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So |
354 | instead of switching to Ruby, I wrote Moose :) |
3c7278fb |
355 | |
8bdc7f13 |
356 | =head2 Wait, I<post> modern, I thought it was just I<modern>? |
357 | |
358 | So I was reading Larry Wall's talk from the 1999 Linux World entitled |
359 | "Perl, the first postmodern computer language" in which he talks about how |
360 | he picked the features for Perl because he thought they were cool and he |
361 | threw out the ones that he thought sucked. This got me thinking about how |
362 | we have done the same thing in Moose. For Moose, we have "borrowed" features |
363 | from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and |
364 | the bits we didn't like (cause they sucked) we tossed aside. So for this |
365 | reason (and a few others) I have re-dubbed Moose a I<postmodern> object system. |
366 | |
367 | Nuff Said. |
368 | |
28669f89 |
369 | =head2 Moose Extensions |
370 | |
371 | The L<MooseX::> namespace is the official place to find Moose extensions. |
0b26305c |
372 | There are a number of these modules out on CPAN right now the best way to |
373 | find them is to search for MooseX:: on search.cpan.org. |
28669f89 |
374 | |
6ba6d68c |
375 | =head1 BUILDING CLASSES WITH MOOSE |
376 | |
68efb014 |
377 | Moose makes every attempt to provide as much convenience as possible during |
378 | class construction/definition, but still stay out of your way if you want it |
379 | to. Here are a few items to note when building classes with Moose. |
6ba6d68c |
380 | |
26fbace8 |
381 | Unless specified with C<extends>, any class which uses Moose will |
6ba6d68c |
382 | inherit from L<Moose::Object>. |
383 | |
1cd45431 |
384 | Moose will also manage all attributes (including inherited ones) that are |
385 | defined with C<has>. And (assuming you call C<new>, which is inherited from |
386 | L<Moose::Object>) this includes properly initializing all instance slots, |
387 | setting defaults where appropriate, and performing any type constraint checking |
388 | or coercion. |
6ba6d68c |
389 | |
004222dc |
390 | =head1 PROVIDED METHODS |
6ba6d68c |
391 | |
004222dc |
392 | Moose provides a number of methods to all your classes, mostly through the |
393 | inheritance of L<Moose::Object>. There is however, one exception. |
6ba6d68c |
394 | |
395 | =over 4 |
396 | |
397 | =item B<meta> |
398 | |
399 | This is a method which provides access to the current class's metaclass. |
400 | |
004222dc |
401 | =back |
402 | |
403 | =head1 EXPORTED FUNCTIONS |
404 | |
405 | Moose will export a number of functions into the class's namespace which |
406 | may then be used to set up the class. These functions all work directly |
407 | on the current class. |
408 | |
409 | =over 4 |
410 | |
6ba6d68c |
411 | =item B<extends (@superclasses)> |
412 | |
413 | This function will set the superclass(es) for the current class. |
414 | |
26fbace8 |
415 | This approach is recommended instead of C<use base>, because C<use base> |
416 | actually C<push>es onto the class's C<@ISA>, whereas C<extends> will |
417 | replace it. This is important to ensure that classes which do not have |
68efb014 |
418 | superclasses still properly inherit from L<Moose::Object>. |
6ba6d68c |
419 | |
43d599e5 |
420 | =item B<with (@roles)> |
e9ec68d6 |
421 | |
004222dc |
422 | This will apply a given set of C<@roles> to the local class. |
e9ec68d6 |
423 | |
cd7eeaf5 |
424 | =item B<has $name =E<gt> %options> |
6ba6d68c |
425 | |
26fbace8 |
426 | This will install an attribute of a given C<$name> into the current class. |
427 | The C<%options> are the same as those provided by |
428 | L<Class::MOP::Attribute>, in addition to the list below which are provided |
43d599e5 |
429 | by Moose (L<Moose::Meta::Attribute> to be more specific): |
6ba6d68c |
430 | |
431 | =over 4 |
432 | |
076c81ed |
433 | =item I<is =E<gt> 'rw'|'ro'> |
6ba6d68c |
434 | |
26fbace8 |
435 | The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read |
436 | only). These will create either a read/write accessor or a read-only |
6ba6d68c |
437 | accessor respectively, using the same name as the C<$name> of the attribute. |
438 | |
1cd45431 |
439 | If you need more control over how your accessors are named, you can use the |
440 | I<reader>, I<writer> and I<accessor> options inherited from |
004222dc |
441 | L<Class::MOP::Attribute>, however if you use those, you won't need the I<is> |
442 | option. |
6ba6d68c |
443 | |
076c81ed |
444 | =item I<isa =E<gt> $type_name> |
6ba6d68c |
445 | |
26fbace8 |
446 | The I<isa> option uses Moose's type constraint facilities to set up runtime |
447 | type checking for this attribute. Moose will perform the checks during class |
448 | construction, and within any accessors. The C<$type_name> argument must be a |
449 | string. The string may be either a class name or a type defined using |
9cca2e9e |
450 | Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints> |
c2a69ef1 |
451 | for information on how to define a new type, and how to retrieve type meta-data). |
6ba6d68c |
452 | |
daea75c9 |
453 | =item I<coerce =E<gt> (1|0)> |
454 | |
26fbace8 |
455 | This will attempt to use coercion with the supplied type constraint to change |
456 | the value passed into any accessors or constructors. You B<must> have supplied |
daea75c9 |
457 | a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5> |
1cd45431 |
458 | for an example. |
daea75c9 |
459 | |
460 | =item I<does =E<gt> $role_name> |
461 | |
26fbace8 |
462 | This will accept the name of a role which the value stored in this attribute |
daea75c9 |
463 | is expected to have consumed. |
464 | |
465 | =item I<required =E<gt> (1|0)> |
466 | |
26fbace8 |
467 | This marks the attribute as being required. This means a I<defined> value must be |
468 | supplied during class construction, and the attribute may never be set to |
469 | C<undef> with an accessor. |
daea75c9 |
470 | |
471 | =item I<weak_ref =E<gt> (1|0)> |
472 | |
68efb014 |
473 | This will tell the class to store the value of this attribute as a weakened |
474 | reference. If an attribute is a weakened reference, it B<cannot> also be |
475 | coerced. |
daea75c9 |
476 | |
477 | =item I<lazy =E<gt> (1|0)> |
478 | |
26fbace8 |
479 | This will tell the class to not create this slot until absolutely necessary. |
daea75c9 |
480 | If an attribute is marked as lazy it B<must> have a default supplied. |
481 | |
9e93dd19 |
482 | =item I<auto_deref =E<gt> (1|0)> |
483 | |
26fbace8 |
484 | This tells the accessor whether to automatically dereference the value returned. |
1cd45431 |
485 | This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>. |
9e93dd19 |
486 | |
daea75c9 |
487 | =item I<trigger =E<gt> $code> |
488 | |
1cd45431 |
489 | The I<trigger> option is a CODE reference which will be called after the value of |
490 | the attribute is set. The CODE ref will be passed the instance itself, the |
daea75c9 |
491 | updated value and the attribute meta-object (this is for more advanced fiddling |
1cd45431 |
492 | and can typically be ignored). You B<cannot> have a trigger on a read-only |
493 | attribute. |
daea75c9 |
494 | |
c84f324f |
495 | =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE> |
2c0cbef7 |
496 | |
26fbace8 |
497 | The I<handles> option provides Moose classes with automated delegation features. |
498 | This is a pretty complex and powerful option. It accepts many different option |
499 | formats, each with its own benefits and drawbacks. |
38e3283b |
500 | |
1cd45431 |
501 | B<NOTE:> The class being delegated to does not need to be a Moose based class, |
502 | which is why this feature is especially useful when wrapping non-Moose classes. |
38e3283b |
503 | |
1cd45431 |
504 | All I<handles> option formats share the following traits: |
38e3283b |
505 | |
1cd45431 |
506 | You cannot override a locally defined method with a delegated method; an |
507 | exception will be thrown if you try. That is to say, if you define C<foo> in |
508 | your class, you cannot override it with a delegated C<foo>. This is almost never |
509 | something you would want to do, and if it is, you should do it by hand and not |
510 | use Moose. |
38e3283b |
511 | |
1cd45431 |
512 | You cannot override any of the methods found in Moose::Object, or the C<BUILD> |
513 | and C<DEMOLISH> methods. These will not throw an exception, but will silently |
514 | move on to the next method in the list. My reasoning for this is that you would |
515 | almost never want to do this, since it usually breaks your class. As with |
516 | overriding locally defined methods, if you do want to do this, you should do it |
517 | manually, not with Moose. |
38e3283b |
518 | |
f3c4e20e |
519 | You do not I<need> to have a reader (or accessor) for the attribute in order |
520 | to delegate to it. Moose will create a means of accessing the value for you, |
521 | however this will be several times B<less> efficient then if you had given |
522 | the attribute a reader (or accessor) to use. |
523 | |
38e3283b |
524 | Below is the documentation for each option format: |
525 | |
526 | =over 4 |
527 | |
528 | =item C<ARRAY> |
529 | |
26fbace8 |
530 | This is the most common usage for I<handles>. You basically pass a list of |
531 | method names to be delegated, and Moose will install a delegation method |
1cd45431 |
532 | for each one. |
38e3283b |
533 | |
534 | =item C<HASH> |
535 | |
26fbace8 |
536 | This is the second most common usage for I<handles>. Instead of a list of |
537 | method names, you pass a HASH ref where each key is the method name you |
538 | want installed locally, and its value is the name of the original method |
539 | in the class being delegated to. |
fd595040 |
540 | |
26fbace8 |
541 | This can be very useful for recursive classes like trees. Here is a |
fd595040 |
542 | quick example (soon to be expanded into a Moose::Cookbook::Recipe): |
38e3283b |
543 | |
1cd45431 |
544 | package Tree; |
38e3283b |
545 | use Moose; |
26fbace8 |
546 | |
38e3283b |
547 | has 'node' => (is => 'rw', isa => 'Any'); |
26fbace8 |
548 | |
38e3283b |
549 | has 'children' => ( |
550 | is => 'ro', |
551 | isa => 'ArrayRef', |
552 | default => sub { [] } |
553 | ); |
26fbace8 |
554 | |
38e3283b |
555 | has 'parent' => ( |
556 | is => 'rw', |
557 | isa => 'Tree', |
a4e516f6 |
558 | weak_ref => 1, |
38e3283b |
559 | handles => { |
560 | parent_node => 'node', |
26fbace8 |
561 | siblings => 'children', |
38e3283b |
562 | } |
563 | ); |
564 | |
1cd45431 |
565 | In this example, the Tree package gets C<parent_node> and C<siblings> methods, |
566 | which delegate to the C<node> and C<children> methods (respectively) of the Tree |
26fbace8 |
567 | instance stored in the C<parent> slot. |
38e3283b |
568 | |
569 | =item C<REGEXP> |
570 | |
26fbace8 |
571 | The regexp option works very similar to the ARRAY option, except that it builds |
572 | the list of methods for you. It starts by collecting all possible methods of the |
573 | class being delegated to, then filters that list using the regexp supplied here. |
38e3283b |
574 | |
26fbace8 |
575 | B<NOTE:> An I<isa> option is required when using the regexp option format. This |
576 | is so that we can determine (at compile time) the method list from the class. |
38e3283b |
577 | Without an I<isa> this is just not possible. |
578 | |
c84f324f |
579 | =item C<ROLE> |
580 | |
26fbace8 |
581 | With the role option, you specify the name of a role whose "interface" then |
582 | becomes the list of methods to handle. The "interface" can be defined as; the |
583 | methods of the role and any required methods of the role. It should be noted |
584 | that this does B<not> include any method modifiers or generated attribute |
c84f324f |
585 | methods (which is consistent with role composition). |
586 | |
38e3283b |
587 | =item C<CODE> |
588 | |
1cd45431 |
589 | This is the option to use when you really want to do something funky. You should |
590 | only use it if you really know what you are doing, as it involves manual |
591 | metaclass twiddling. |
38e3283b |
592 | |
1cd45431 |
593 | This takes a code reference, which should expect two arguments. The first is the |
594 | attribute meta-object this I<handles> is attached to. The second is the |
595 | metaclass of the class being delegated to. It expects you to return a hash (not |
26fbace8 |
596 | a HASH ref) of the methods you want mapped. |
38e3283b |
597 | |
598 | =back |
2c0cbef7 |
599 | |
004222dc |
600 | =item I<metaclass =E<gt> $metaclass_name> |
601 | |
602 | This tells the class to use a custom attribute metaclass for this particular |
603 | attribute. Custom attribute metaclasses are useful for extending the |
604 | capabilities of the I<has> keyword: they are the simplest way to extend the MOP, |
605 | but they are still a fairly advanced topic and too much to cover here, see |
606 | L<Moose::Cookbook::Recipe11> for more information. |
607 | |
608 | The default behavior here is to just load C<$metaclass_name>; however, we also |
609 | have a way to alias to a shorter name. This will first look to see if |
610 | B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose |
611 | will then check to see if that has the method C<register_implementation>, which |
612 | should return the actual name of the custom attribute metaclass. If there is no |
613 | C<register_implementation> method, it will fall back to using |
614 | B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name. |
615 | |
616 | =item I<traits =E<gt> [ @role_names ]> |
617 | |
618 | This tells Moose to take the list of C<@role_names> and apply them to the |
619 | attribute meta-object. This is very similar to the I<metaclass> option, but |
620 | allows you to use more than one extension at a time. This too is an advanced |
621 | topic, we don't yet have a cookbook for it though. |
622 | |
623 | As with I<metaclass>, the default behavior is to just load C<$role_name>; however, |
624 | we also have a way to alias to a shorter name. This will first look to see if |
625 | B<Moose::Meta::Attribute::Custom::Trait::$role_name> exists. If it does, Moose |
626 | will then check to see if that has the method C<register_implementation>, which |
627 | should return the actual name of the custom attribute trait. If there is no |
628 | C<register_implementation> method, it will fall back to using |
629 | B<Moose::Meta::Attribute::Custom::Trait::$metaclass_name> as the trait name. |
630 | |
6ba6d68c |
631 | =back |
632 | |
cd7eeaf5 |
633 | =item B<has +$name =E<gt> %options> |
634 | |
26fbace8 |
635 | This is variation on the normal attibute creator C<has> which allows you to |
8d62bf6d |
636 | clone and extend an attribute from a superclass or from a role. Here is an |
637 | example of the superclass usage: |
cd7eeaf5 |
638 | |
639 | package Foo; |
640 | use Moose; |
26fbace8 |
641 | |
cd7eeaf5 |
642 | has 'message' => ( |
26fbace8 |
643 | is => 'rw', |
cd7eeaf5 |
644 | isa => 'Str', |
645 | default => 'Hello, I am a Foo' |
646 | ); |
26fbace8 |
647 | |
cd7eeaf5 |
648 | package My::Foo; |
649 | use Moose; |
26fbace8 |
650 | |
cd7eeaf5 |
651 | extends 'Foo'; |
26fbace8 |
652 | |
cd7eeaf5 |
653 | has '+message' => (default => 'Hello I am My::Foo'); |
654 | |
1cd45431 |
655 | What is happening here is that B<My::Foo> is cloning the C<message> attribute |
656 | from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt> |
657 | 'Str'> characteristics, but changing the value in C<default>. |
cd7eeaf5 |
658 | |
8d62bf6d |
659 | Here is another example, but within the context of a role: |
660 | |
661 | package Foo::Role; |
662 | use Moose::Role; |
663 | |
664 | has 'message' => ( |
665 | is => 'rw', |
666 | isa => 'Str', |
667 | default => 'Hello, I am a Foo' |
668 | ); |
669 | |
670 | package My::Foo; |
671 | use Moose; |
672 | |
673 | with 'Foo::Role'; |
674 | |
675 | has '+message' => (default => 'Hello I am My::Foo'); |
676 | |
677 | In this case, we are basically taking the attribute which the role supplied |
4032c9bb |
678 | and altering it within the bounds of this feature. |
8d62bf6d |
679 | |
4032c9bb |
680 | Aside from where the attributes come from (one from superclass, the other |
681 | from a role), this feature works exactly the same. This feature is restricted |
682 | somewhat, so as to try and force at least I<some> sanity into it. You are only |
683 | allowed to change the following attributes: |
cd7eeaf5 |
684 | |
685 | =over 4 |
686 | |
26fbace8 |
687 | =item I<default> |
cd7eeaf5 |
688 | |
689 | Change the default value of an attribute. |
690 | |
26fbace8 |
691 | =item I<coerce> |
cd7eeaf5 |
692 | |
693 | Change whether the attribute attempts to coerce a value passed to it. |
694 | |
26fbace8 |
695 | =item I<required> |
cd7eeaf5 |
696 | |
697 | Change if the attribute is required to have a value. |
698 | |
699 | =item I<documentation> |
700 | |
701 | Change the documentation string associated with the attribute. |
702 | |
83cc9094 |
703 | =item I<lazy> |
704 | |
705 | Change if the attribute lazily initializes the slot. |
706 | |
cd7eeaf5 |
707 | =item I<isa> |
708 | |
aed87761 |
709 | You I<are> allowed to change the type without restriction. |
710 | |
711 | It is recommended that you use this freedom with caution. We used to |
712 | only allow for extension only if the type was a subtype of the parent's |
713 | type, but we felt that was too restrictive and is better left as a |
714 | policy descision. |
cd7eeaf5 |
715 | |
83cc9094 |
716 | =item I<handles> |
717 | |
26fbace8 |
718 | You are allowed to B<add> a new C<handles> definition, but you are B<not> |
719 | allowed to I<change> one. |
83cc9094 |
720 | |
8d62bf6d |
721 | =item I<builder> |
722 | |
723 | You are allowed to B<add> a new C<builder> definition, but you are B<not> |
724 | allowed to I<change> one. |
725 | |
13284479 |
726 | =item I<metaclass> |
727 | |
728 | You are allowed to B<add> a new C<metaclass> definition, but you are |
729 | B<not> allowed to I<change> one. |
730 | |
731 | =item I<traits> |
732 | |
733 | You are allowed to B<add> additional traits to the C<traits> definition. |
734 | These traits will be composed into the attribute, but pre-existing traits |
735 | B<are not> overridden, or removed. |
736 | |
cd7eeaf5 |
737 | =back |
738 | |
076c81ed |
739 | =item B<before $name|@names =E<gt> sub { ... }> |
6ba6d68c |
740 | |
076c81ed |
741 | =item B<after $name|@names =E<gt> sub { ... }> |
6ba6d68c |
742 | |
076c81ed |
743 | =item B<around $name|@names =E<gt> sub { ... }> |
6ba6d68c |
744 | |
d8af92ae |
745 | This three items are syntactic sugar for the before, after, and around method |
746 | modifier features that L<Class::MOP> provides. More information on these may be |
747 | found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method |
748 | Modifiers"> for now. |
6ba6d68c |
749 | |
159da176 |
750 | =item B<super> |
751 | |
26fbace8 |
752 | The keyword C<super> is a no-op when called outside of an C<override> method. In |
753 | the context of an C<override> method, it will call the next most appropriate |
159da176 |
754 | superclass method with the same arguments as the original method. |
755 | |
756 | =item B<override ($name, &sub)> |
757 | |
26fbace8 |
758 | An C<override> method is a way of explicitly saying "I am overriding this |
759 | method from my superclass". You can call C<super> within this method, and |
760 | it will work as expected. The same thing I<can> be accomplished with a normal |
761 | method call and the C<SUPER::> pseudo-package; it is really your choice. |
159da176 |
762 | |
763 | =item B<inner> |
764 | |
26fbace8 |
765 | The keyword C<inner>, much like C<super>, is a no-op outside of the context of |
766 | an C<augment> method. You can think of C<inner> as being the inverse of |
68efb014 |
767 | C<super>; the details of how C<inner> and C<augment> work is best described in |
004222dc |
768 | the L<Moose::Cookbook::Recipe7>. |
159da176 |
769 | |
770 | =item B<augment ($name, &sub)> |
771 | |
26fbace8 |
772 | An C<augment> method, is a way of explicitly saying "I am augmenting this |
773 | method from my superclass". Once again, the details of how C<inner> and |
004222dc |
774 | C<augment> work is best described in the L<Moose::Cookbook::Recipe7>. |
159da176 |
775 | |
6ba6d68c |
776 | =item B<confess> |
777 | |
68efb014 |
778 | This is the C<Carp::confess> function, and exported here because I use it |
004222dc |
779 | all the time. |
6ba6d68c |
780 | |
781 | =item B<blessed> |
782 | |
1cd45431 |
783 | This is the C<Scalar::Util::blessed> function, it is exported here because I |
26fbace8 |
784 | use it all the time. It is highly recommended that this is used instead of |
6ba6d68c |
785 | C<ref> anywhere you need to test for an object's class name. |
786 | |
787 | =back |
788 | |
1cd45431 |
789 | =head1 UNIMPORTING FUNCTIONS |
31f8ec72 |
790 | |
791 | =head2 B<unimport> |
792 | |
1cd45431 |
793 | Moose offers a way to remove the keywords it exports, through the C<unimport> |
31f8ec72 |
794 | method. You simply have to say C<no Moose> at the bottom of your code for this |
795 | to work. Here is an example: |
796 | |
797 | package Person; |
798 | use Moose; |
799 | |
800 | has 'first_name' => (is => 'rw', isa => 'Str'); |
801 | has 'last_name' => (is => 'rw', isa => 'Str'); |
26fbace8 |
802 | |
803 | sub full_name { |
31f8ec72 |
804 | my $self = shift; |
26fbace8 |
805 | $self->first_name . ' ' . $self->last_name |
31f8ec72 |
806 | } |
26fbace8 |
807 | |
808 | no Moose; # keywords are removed from the Person package |
31f8ec72 |
809 | |
9bcfbab1 |
810 | =head1 EXTENDING AND EMBEDDING MOOSE |
811 | |
26fbace8 |
812 | Moose also offers some options for extending or embedding it into your own |
9bcfbab1 |
813 | framework. The basic premise is to have something that sets up your class' |
26fbace8 |
814 | metaclass and export the moose declarators (C<has>, C<with>, C<extends>,...). |
9bcfbab1 |
815 | Here is an example: |
816 | |
817 | package MyFramework; |
818 | use Moose; |
26fbace8 |
819 | |
9bcfbab1 |
820 | sub import { |
821 | my $CALLER = caller(); |
822 | |
823 | strict->import; |
824 | warnings->import; |
825 | |
826 | # we should never export to main |
827 | return if $CALLER eq 'main'; |
828 | Moose::init_meta( $CALLER, 'MyFramework::Base' ); |
829 | Moose->import({into => $CALLER}); |
830 | |
831 | # Do my custom framework stuff |
26fbace8 |
832 | |
9bcfbab1 |
833 | return 1; |
834 | } |
26fbace8 |
835 | |
9bcfbab1 |
836 | =head2 B<import> |
837 | |
77a18c28 |
838 | Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}> |
9bcfbab1 |
839 | and C<{into_level =E<gt> 1}> |
840 | |
841 | =head2 B<init_meta ($class, $baseclass, $metaclass)> |
842 | |
26fbace8 |
843 | Moose does some boot strapping: it creates a metaclass object for your class, |
844 | and then injects a C<meta> accessor into your class to retrieve it. Then it |
845 | sets your baseclass to Moose::Object or the value you pass in unless you already |
846 | have one. This is all done via C<init_meta> which takes the name of your class |
2bbba362 |
847 | and optionally a baseclass and a metaclass as arguments. |
26fbace8 |
848 | |
05d9eaf6 |
849 | =head1 CAVEATS |
850 | |
851 | =over 4 |
852 | |
853 | =item * |
854 | |
1cd45431 |
855 | It should be noted that C<super> and C<inner> B<cannot> be used in the same |
856 | method. However, they may be combined within the same class hierarchy; see |
857 | F<t/014_override_augment_inner_super.t> for an example. |
05d9eaf6 |
858 | |
26fbace8 |
859 | The reason for this is that C<super> is only valid within a method |
860 | with the C<override> modifier, and C<inner> will never be valid within an |
861 | C<override> method. In fact, C<augment> will skip over any C<override> methods |
68efb014 |
862 | when searching for its appropriate C<inner>. |
05d9eaf6 |
863 | |
1cd45431 |
864 | This might seem like a restriction, but I am of the opinion that keeping these |
865 | two features separate (yet interoperable) actually makes them easy to use, since |
866 | their behavior is then easier to predict. Time will tell whether I am right or |
c84f324f |
867 | not (UPDATE: so far so good). |
05d9eaf6 |
868 | |
004222dc |
869 | =item * |
870 | |
871 | It is important to note that we currently have no simple way of combining |
872 | multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above), |
873 | and that in many cases they will conflict with one another. We are working on |
874 | developing a way around this issue, but in the meantime, you have been warned. |
875 | |
05d9eaf6 |
876 | =back |
877 | |
5569c072 |
878 | =head1 ACKNOWLEDGEMENTS |
879 | |
880 | =over 4 |
881 | |
54c189df |
882 | =item I blame Sam Vilain for introducing me to the insanity that is meta-models. |
5569c072 |
883 | |
54c189df |
884 | =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6. |
5569c072 |
885 | |
26fbace8 |
886 | =item Without Yuval "nothingmuch" Kogman this module would not be possible, |
54c189df |
887 | and it certainly wouldn't have this name ;P |
5569c072 |
888 | |
26fbace8 |
889 | =item The basis of the TypeContraints module was Rob Kinyon's idea |
5569c072 |
890 | originally, I just ran with it. |
891 | |
638585e1 |
892 | =item Thanks to mst & chansen and the whole #moose posse for all the |
c84f324f |
893 | early ideas/feature-requests/encouragement/bug-finding. |
d46a48f3 |
894 | |
68efb014 |
895 | =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes. |
896 | |
5569c072 |
897 | =back |
898 | |
e90c03d0 |
899 | =head1 SEE ALSO |
900 | |
901 | =over 4 |
902 | |
c84f324f |
903 | =item L<http://www.iinteractive.com/moose> |
904 | |
905 | This is the official web home of Moose, it contains links to our public SVN repo |
26fbace8 |
906 | as well as links to a number of talks and articles on Moose and Moose related |
907 | technologies. |
c84f324f |
908 | |
6ba6d68c |
909 | =item L<Class::MOP> documentation |
910 | |
911 | =item The #moose channel on irc.perl.org |
912 | |
e67a0fca |
913 | =item The Moose mailing list - moose@perl.org |
914 | |
c84f324f |
915 | =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/5788> |
916 | |
28669f89 |
917 | =item Several Moose extension modules in the L<MooseX::> namespace. |
918 | |
c84f324f |
919 | =back |
920 | |
004222dc |
921 | =head2 Books |
922 | |
923 | =over 4 |
924 | |
925 | =item The Art of the MetaObject Protocol |
926 | |
927 | I mention this in the L<Class::MOP> docs too, this book was critical in |
928 | the development of both modules and is highly recommended. |
929 | |
930 | =back |
931 | |
26fbace8 |
932 | =head2 Papers |
c84f324f |
933 | |
934 | =over 4 |
e90c03d0 |
935 | |
159da176 |
936 | =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf> |
937 | |
26fbace8 |
938 | This paper (suggested by lbr on #moose) was what lead to the implementation |
939 | of the C<super>/C<override> and C<inner>/C<augment> features. If you really |
1cd45431 |
940 | want to understand them, I suggest you read this. |
159da176 |
941 | |
e90c03d0 |
942 | =back |
943 | |
fcd84ca9 |
944 | =head1 BUGS |
945 | |
26fbace8 |
946 | All complex software has bugs lurking in it, and this module is no |
fcd84ca9 |
947 | exception. If you find a bug please either email me, or add the bug |
948 | to cpan-RT. |
949 | |
fcd84ca9 |
950 | =head1 AUTHOR |
951 | |
952 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
953 | |
9af1d28b |
954 | B<with contributions from:> |
db1ab48d |
955 | |
9af1d28b |
956 | Aankhen |
957 | |
958 | Adam (Alias) Kennedy |
959 | |
960 | Anders (Debolaz) Nor Berle |
961 | |
5868294f |
962 | Nathan (kolibre) Gray |
963 | |
9af1d28b |
964 | Christian (chansen) Hansen |
965 | |
e7f8d0c2 |
966 | Hans Dieter (confound) Pearcey |
967 | |
9af1d28b |
968 | Eric (ewilhelm) Wilhelm |
969 | |
970 | Guillermo (groditi) Roditi |
971 | |
972 | Jess (castaway) Robinson |
973 | |
974 | Matt (mst) Trout |
975 | |
976 | Robert (phaylon) Sedlacek |
977 | |
978 | Robert (rlb3) Boone |
979 | |
980 | Scott (konobi) McWhirter |
981 | |
f44ae52f |
982 | Shlomi (rindolf) Fish |
983 | |
9af1d28b |
984 | Yuval (nothingmuch) Kogman |
985 | |
cbe25729 |
986 | Chris (perigrin) Prather |
987 | |
e46f5cc2 |
988 | Jonathan (jrockway) Rockway |
989 | |
3ccdc84a |
990 | Piotr (dexter) Roszatycki |
991 | |
26fbace8 |
992 | Sam (mugwump) Vilain |
f1917f58 |
993 | |
ac211120 |
994 | Shawn (sartak) Moore |
995 | |
9af1d28b |
996 | ... and many other #moose folks |
98aae381 |
997 | |
fcd84ca9 |
998 | =head1 COPYRIGHT AND LICENSE |
999 | |
778db3ac |
1000 | Copyright 2006-2008 by Infinity Interactive, Inc. |
fcd84ca9 |
1001 | |
1002 | L<http://www.iinteractive.com> |
1003 | |
1004 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
1005 | it under the same terms as Perl itself. |
fcd84ca9 |
1006 | |
ddd0ec20 |
1007 | =cut |