Commit | Line | Data |
fcd84ca9 |
1 | |
2 | package Moose; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
c2922d69 |
7 | our $VERSION = '0.41'; |
d44714be |
8 | our $AUTHORITY = 'cpan:STEVAN'; |
fcd84ca9 |
9 | |
cc65ead0 |
10 | use Scalar::Util 'blessed', 'reftype'; |
547dda77 |
11 | use Carp 'confess', 'croak'; |
3796382a |
12 | use Sub::Name 'subname'; |
fcd84ca9 |
13 | |
2d562421 |
14 | use Sub::Exporter; |
7f18097c |
15 | |
c2922d69 |
16 | use Class::MOP; |
ef1d5f4b |
17 | |
c0e30cf5 |
18 | use Moose::Meta::Class; |
7415b2cb |
19 | use Moose::Meta::TypeConstraint; |
3fef8ce8 |
20 | use Moose::Meta::TypeConstraint::Class; |
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 { |
52c7c330 |
139 | { |
9bcfbab1 |
140 | our %SUPER_SLOT; |
141 | no strict 'refs'; |
142 | $SUPER_SLOT{$CALLER} = \*{"${CALLER}::super"}; |
52c7c330 |
143 | } |
9bcfbab1 |
144 | return subname 'Moose::super' => sub { }; |
a3c7e2fe |
145 | }, |
146 | override => sub { |
be33e4f3 |
147 | my $class = $CALLER; |
2c0cbef7 |
148 | return subname 'Moose::override' => sub ($&) { |
9bcfbab1 |
149 | my ( $name, $method ) = @_; |
150 | $class->meta->add_override_method_modifier( $name => $method ); |
a3c7e2fe |
151 | }; |
152 | }, |
153 | inner => sub { |
52c7c330 |
154 | { |
9bcfbab1 |
155 | our %INNER_SLOT; |
156 | no strict 'refs'; |
157 | $INNER_SLOT{$CALLER} = \*{"${CALLER}::inner"}; |
52c7c330 |
158 | } |
9bcfbab1 |
159 | return subname 'Moose::inner' => sub { }; |
a3c7e2fe |
160 | }, |
161 | augment => sub { |
be33e4f3 |
162 | my $class = $CALLER; |
2c0cbef7 |
163 | return subname 'Moose::augment' => sub (@&) { |
9bcfbab1 |
164 | my ( $name, $method ) = @_; |
165 | $class->meta->add_augment_method_modifier( $name => $method ); |
a3c7e2fe |
166 | }; |
167 | }, |
2a5e59d0 |
168 | make_immutable => sub { |
169 | my $class = $CALLER; |
170 | return subname 'Moose::make_immutable' => sub { |
c2922d69 |
171 | warn "The make_immutable keyword has been deprecated, " . |
172 | "please go back to __PACKAGE__->meta->make_immutable\n"; |
e902b1a5 |
173 | $class->meta->make_immutable(@_); |
2a5e59d0 |
174 | }; |
175 | }, |
a3c7e2fe |
176 | confess => sub { |
177 | return \&Carp::confess; |
178 | }, |
179 | blessed => sub { |
180 | return \&Scalar::Util::blessed; |
66bcefc1 |
181 | }, |
a3c7e2fe |
182 | ); |
3d544ed5 |
183 | |
9bcfbab1 |
184 | my $exporter = Sub::Exporter::build_exporter( |
185 | { |
186 | exports => \%exports, |
187 | groups => { default => [':all'] } |
a3c7e2fe |
188 | } |
9bcfbab1 |
189 | ); |
190 | |
c92c1205 |
191 | # 1 extra level because it's called by import so there's a layer of indirection |
192 | sub _get_caller{ |
193 | my $offset = 1; |
26fbace8 |
194 | return |
c92c1205 |
195 | ref $_[1] && defined $_[1]->{into} |
196 | ? $_[1]->{into} |
197 | : ref $_[1] && defined $_[1]->{into_level} |
198 | ? caller($offset + $_[1]->{into_level}) |
199 | : caller($offset); |
200 | } |
5bee491d |
201 | |
202 | sub import { |
c92c1205 |
203 | $CALLER = _get_caller(@_); |
26fbace8 |
204 | |
86dd5d11 |
205 | # this works because both pragmas set $^H (see perldoc perlvar) |
206 | # which affects the current compilation - i.e. the file who use'd |
207 | # us - which is why we don't need to do anything special to make |
208 | # it affect that file rather than this one (which is already compiled) |
209 | |
c235cd98 |
210 | strict->import; |
9bcfbab1 |
211 | warnings->import; |
a3c7e2fe |
212 | |
213 | # we should never export to main |
214 | return if $CALLER eq 'main'; |
9bcfbab1 |
215 | |
216 | init_meta( $CALLER, 'Moose::Object' ); |
217 | |
a3c7e2fe |
218 | goto $exporter; |
fcb7afc2 |
219 | } |
9bcfbab1 |
220 | |
31f8ec72 |
221 | sub unimport { |
9bcfbab1 |
222 | no strict 'refs'; |
c92c1205 |
223 | my $class = _get_caller(@_); |
9bcfbab1 |
224 | |
31f8ec72 |
225 | # loop through the exports ... |
9bcfbab1 |
226 | foreach my $name ( keys %exports ) { |
227 | |
31f8ec72 |
228 | # if we find one ... |
9bcfbab1 |
229 | if ( defined &{ $class . '::' . $name } ) { |
230 | my $keyword = \&{ $class . '::' . $name }; |
231 | |
31f8ec72 |
232 | # make sure it is from Moose |
53dd42d8 |
233 | my ($pkg_name) = Class::MOP::get_code_info($keyword); |
31f8ec72 |
234 | next if $@; |
235 | next if $pkg_name ne 'Moose'; |
9bcfbab1 |
236 | |
31f8ec72 |
237 | # and if it is from Moose then undef the slot |
9bcfbab1 |
238 | delete ${ $class . '::' }{$name}; |
31f8ec72 |
239 | } |
240 | } |
241 | } |
9bcfbab1 |
242 | |
fcd84ca9 |
243 | } |
244 | |
8ecb1fa0 |
245 | ## make 'em all immutable |
246 | |
247 | $_->meta->make_immutable( |
248 | inline_constructor => 0, |
77a18c28 |
249 | inline_accessors => 1, # these are Class::MOP accessors, so they need inlining |
9bcfbab1 |
250 | ) |
251 | for ( |
8ecb1fa0 |
252 | 'Moose::Meta::Attribute', |
253 | 'Moose::Meta::Class', |
254 | 'Moose::Meta::Instance', |
255 | |
256 | 'Moose::Meta::TypeConstraint', |
257 | 'Moose::Meta::TypeConstraint::Union', |
0fbd4b0a |
258 | 'Moose::Meta::TypeConstraint::Parameterized', |
8ecb1fa0 |
259 | 'Moose::Meta::TypeCoercion', |
260 | |
261 | 'Moose::Meta::Method', |
262 | 'Moose::Meta::Method::Accessor', |
263 | 'Moose::Meta::Method::Constructor', |
9bcfbab1 |
264 | 'Moose::Meta::Method::Destructor', |
8ecb1fa0 |
265 | 'Moose::Meta::Method::Overriden', |
d67145ed |
266 | |
267 | 'Moose::Meta::Role', |
9bcfbab1 |
268 | 'Moose::Meta::Role::Method', |
269 | 'Moose::Meta::Role::Method::Required', |
270 | ); |
8ecb1fa0 |
271 | |
fcd84ca9 |
272 | 1; |
273 | |
274 | __END__ |
275 | |
276 | =pod |
277 | |
278 | =head1 NAME |
279 | |
8bdc7f13 |
280 | Moose - A postmodern object system for Perl 5 |
fcd84ca9 |
281 | |
282 | =head1 SYNOPSIS |
e522431d |
283 | |
284 | package Point; |
1cd45431 |
285 | use Moose; # automatically turns on strict and warnings |
26fbace8 |
286 | |
43d599e5 |
287 | has 'x' => (is => 'rw', isa => 'Int'); |
288 | has 'y' => (is => 'rw', isa => 'Int'); |
26fbace8 |
289 | |
e522431d |
290 | sub clear { |
291 | my $self = shift; |
292 | $self->x(0); |
26fbace8 |
293 | $self->y(0); |
e522431d |
294 | } |
26fbace8 |
295 | |
e522431d |
296 | package Point3D; |
297 | use Moose; |
26fbace8 |
298 | |
e522431d |
299 | extends 'Point'; |
26fbace8 |
300 | |
43d599e5 |
301 | has 'z' => (is => 'rw', isa => 'Int'); |
26fbace8 |
302 | |
e522431d |
303 | after 'clear' => sub { |
304 | my $self = shift; |
43d599e5 |
305 | $self->z(0); |
26fbace8 |
306 | }; |
2c0cbef7 |
307 | |
fcd84ca9 |
308 | =head1 DESCRIPTION |
309 | |
26fbace8 |
310 | Moose is an extension of the Perl 5 object system. |
e522431d |
311 | |
312 | =head2 Another object system!?!? |
fcd84ca9 |
313 | |
26fbace8 |
314 | Yes, I know there has been an explosion recently of new ways to |
68efb014 |
315 | build object's in Perl 5, most of them based on inside-out objects |
26fbace8 |
316 | and other such things. Moose is different because it is not a new |
317 | object system for Perl 5, but instead an extension of the existing |
e522431d |
318 | object system. |
3c7278fb |
319 | |
26fbace8 |
320 | Moose is built on top of L<Class::MOP>, which is a metaclass system |
321 | for Perl 5. This means that Moose not only makes building normal |
322 | Perl 5 objects better, but it also provides the power of metaclass |
505c6fac |
323 | programming. |
e522431d |
324 | |
734d1752 |
325 | =head2 Is this for real? Or is this just an experiment? |
e522431d |
326 | |
2c0cbef7 |
327 | Moose is I<based> on the prototypes and experiments I did for the Perl 6 |
26fbace8 |
328 | meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>. |
734d1752 |
329 | |
26fbace8 |
330 | =head2 Is this ready for use in production? |
d44714be |
331 | |
26fbace8 |
332 | Yes, I believe that it is. |
734d1752 |
333 | |
26fbace8 |
334 | Moose has been used successfully in production environemnts by several people |
335 | and companies (including the one I work for). There are Moose applications |
8bdc7f13 |
336 | which have been in production with little or no issue now for well over a year. |
26fbace8 |
337 | I consider it highly stable and we are commited to keeping it stable. |
e522431d |
338 | |
26fbace8 |
339 | Of course, in the end, you need to make this call yourself. If you have |
340 | any questions or concerns, please feel free to email me, or even the list |
d44714be |
341 | or just stop by #moose and ask away. |
342 | |
43d599e5 |
343 | =head2 Is Moose just Perl 6 in Perl 5? |
e522431d |
344 | |
68efb014 |
345 | No. While Moose is very much inspired by Perl 6, it is not itself Perl 6. |
1cd45431 |
346 | Instead, it is an OO system for Perl 5. I built Moose because I was tired of |
68efb014 |
347 | writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So |
348 | instead of switching to Ruby, I wrote Moose :) |
3c7278fb |
349 | |
8bdc7f13 |
350 | =head2 Wait, I<post> modern, I thought it was just I<modern>? |
351 | |
352 | So I was reading Larry Wall's talk from the 1999 Linux World entitled |
353 | "Perl, the first postmodern computer language" in which he talks about how |
354 | he picked the features for Perl because he thought they were cool and he |
355 | threw out the ones that he thought sucked. This got me thinking about how |
356 | we have done the same thing in Moose. For Moose, we have "borrowed" features |
357 | from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and |
358 | the bits we didn't like (cause they sucked) we tossed aside. So for this |
359 | reason (and a few others) I have re-dubbed Moose a I<postmodern> object system. |
360 | |
361 | Nuff Said. |
362 | |
28669f89 |
363 | =head2 Moose Extensions |
364 | |
365 | The L<MooseX::> namespace is the official place to find Moose extensions. |
0b26305c |
366 | There are a number of these modules out on CPAN right now the best way to |
367 | find them is to search for MooseX:: on search.cpan.org. |
28669f89 |
368 | |
6ba6d68c |
369 | =head1 BUILDING CLASSES WITH MOOSE |
370 | |
68efb014 |
371 | Moose makes every attempt to provide as much convenience as possible during |
372 | class construction/definition, but still stay out of your way if you want it |
373 | to. Here are a few items to note when building classes with Moose. |
6ba6d68c |
374 | |
26fbace8 |
375 | Unless specified with C<extends>, any class which uses Moose will |
6ba6d68c |
376 | inherit from L<Moose::Object>. |
377 | |
1cd45431 |
378 | Moose will also manage all attributes (including inherited ones) that are |
379 | defined with C<has>. And (assuming you call C<new>, which is inherited from |
380 | L<Moose::Object>) this includes properly initializing all instance slots, |
381 | setting defaults where appropriate, and performing any type constraint checking |
382 | or coercion. |
6ba6d68c |
383 | |
004222dc |
384 | =head1 PROVIDED METHODS |
6ba6d68c |
385 | |
004222dc |
386 | Moose provides a number of methods to all your classes, mostly through the |
387 | inheritance of L<Moose::Object>. There is however, one exception. |
6ba6d68c |
388 | |
389 | =over 4 |
390 | |
391 | =item B<meta> |
392 | |
393 | This is a method which provides access to the current class's metaclass. |
394 | |
004222dc |
395 | =back |
396 | |
397 | =head1 EXPORTED FUNCTIONS |
398 | |
399 | Moose will export a number of functions into the class's namespace which |
400 | may then be used to set up the class. These functions all work directly |
401 | on the current class. |
402 | |
403 | =over 4 |
404 | |
6ba6d68c |
405 | =item B<extends (@superclasses)> |
406 | |
407 | This function will set the superclass(es) for the current class. |
408 | |
26fbace8 |
409 | This approach is recommended instead of C<use base>, because C<use base> |
410 | actually C<push>es onto the class's C<@ISA>, whereas C<extends> will |
411 | replace it. This is important to ensure that classes which do not have |
68efb014 |
412 | superclasses still properly inherit from L<Moose::Object>. |
6ba6d68c |
413 | |
43d599e5 |
414 | =item B<with (@roles)> |
e9ec68d6 |
415 | |
004222dc |
416 | This will apply a given set of C<@roles> to the local class. |
e9ec68d6 |
417 | |
cd7eeaf5 |
418 | =item B<has $name =E<gt> %options> |
6ba6d68c |
419 | |
26fbace8 |
420 | This will install an attribute of a given C<$name> into the current class. |
421 | The C<%options> are the same as those provided by |
422 | L<Class::MOP::Attribute>, in addition to the list below which are provided |
43d599e5 |
423 | by Moose (L<Moose::Meta::Attribute> to be more specific): |
6ba6d68c |
424 | |
425 | =over 4 |
426 | |
076c81ed |
427 | =item I<is =E<gt> 'rw'|'ro'> |
6ba6d68c |
428 | |
26fbace8 |
429 | The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read |
430 | only). These will create either a read/write accessor or a read-only |
6ba6d68c |
431 | accessor respectively, using the same name as the C<$name> of the attribute. |
432 | |
1cd45431 |
433 | If you need more control over how your accessors are named, you can use the |
434 | I<reader>, I<writer> and I<accessor> options inherited from |
004222dc |
435 | L<Class::MOP::Attribute>, however if you use those, you won't need the I<is> |
436 | option. |
6ba6d68c |
437 | |
076c81ed |
438 | =item I<isa =E<gt> $type_name> |
6ba6d68c |
439 | |
26fbace8 |
440 | The I<isa> option uses Moose's type constraint facilities to set up runtime |
441 | type checking for this attribute. Moose will perform the checks during class |
442 | construction, and within any accessors. The C<$type_name> argument must be a |
443 | string. The string may be either a class name or a type defined using |
9cca2e9e |
444 | Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints> |
c2a69ef1 |
445 | for information on how to define a new type, and how to retrieve type meta-data). |
6ba6d68c |
446 | |
daea75c9 |
447 | =item I<coerce =E<gt> (1|0)> |
448 | |
26fbace8 |
449 | This will attempt to use coercion with the supplied type constraint to change |
450 | the value passed into any accessors or constructors. You B<must> have supplied |
daea75c9 |
451 | a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5> |
1cd45431 |
452 | for an example. |
daea75c9 |
453 | |
454 | =item I<does =E<gt> $role_name> |
455 | |
26fbace8 |
456 | This will accept the name of a role which the value stored in this attribute |
daea75c9 |
457 | is expected to have consumed. |
458 | |
459 | =item I<required =E<gt> (1|0)> |
460 | |
26fbace8 |
461 | This marks the attribute as being required. This means a I<defined> value must be |
462 | supplied during class construction, and the attribute may never be set to |
463 | C<undef> with an accessor. |
daea75c9 |
464 | |
465 | =item I<weak_ref =E<gt> (1|0)> |
466 | |
68efb014 |
467 | This will tell the class to store the value of this attribute as a weakened |
468 | reference. If an attribute is a weakened reference, it B<cannot> also be |
469 | coerced. |
daea75c9 |
470 | |
471 | =item I<lazy =E<gt> (1|0)> |
472 | |
26fbace8 |
473 | This will tell the class to not create this slot until absolutely necessary. |
daea75c9 |
474 | If an attribute is marked as lazy it B<must> have a default supplied. |
475 | |
9e93dd19 |
476 | =item I<auto_deref =E<gt> (1|0)> |
477 | |
26fbace8 |
478 | This tells the accessor whether to automatically dereference the value returned. |
1cd45431 |
479 | This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>. |
9e93dd19 |
480 | |
daea75c9 |
481 | =item I<trigger =E<gt> $code> |
482 | |
1cd45431 |
483 | The I<trigger> option is a CODE reference which will be called after the value of |
484 | the attribute is set. The CODE ref will be passed the instance itself, the |
daea75c9 |
485 | updated value and the attribute meta-object (this is for more advanced fiddling |
1cd45431 |
486 | and can typically be ignored). You B<cannot> have a trigger on a read-only |
487 | attribute. |
daea75c9 |
488 | |
c84f324f |
489 | =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE> |
2c0cbef7 |
490 | |
26fbace8 |
491 | The I<handles> option provides Moose classes with automated delegation features. |
492 | This is a pretty complex and powerful option. It accepts many different option |
493 | formats, each with its own benefits and drawbacks. |
38e3283b |
494 | |
1cd45431 |
495 | B<NOTE:> The class being delegated to does not need to be a Moose based class, |
496 | which is why this feature is especially useful when wrapping non-Moose classes. |
38e3283b |
497 | |
1cd45431 |
498 | All I<handles> option formats share the following traits: |
38e3283b |
499 | |
1cd45431 |
500 | You cannot override a locally defined method with a delegated method; an |
501 | exception will be thrown if you try. That is to say, if you define C<foo> in |
502 | your class, you cannot override it with a delegated C<foo>. This is almost never |
503 | something you would want to do, and if it is, you should do it by hand and not |
504 | use Moose. |
38e3283b |
505 | |
1cd45431 |
506 | You cannot override any of the methods found in Moose::Object, or the C<BUILD> |
507 | and C<DEMOLISH> methods. These will not throw an exception, but will silently |
508 | move on to the next method in the list. My reasoning for this is that you would |
509 | almost never want to do this, since it usually breaks your class. As with |
510 | overriding locally defined methods, if you do want to do this, you should do it |
511 | manually, not with Moose. |
38e3283b |
512 | |
f3c4e20e |
513 | You do not I<need> to have a reader (or accessor) for the attribute in order |
514 | to delegate to it. Moose will create a means of accessing the value for you, |
515 | however this will be several times B<less> efficient then if you had given |
516 | the attribute a reader (or accessor) to use. |
517 | |
38e3283b |
518 | Below is the documentation for each option format: |
519 | |
520 | =over 4 |
521 | |
522 | =item C<ARRAY> |
523 | |
26fbace8 |
524 | This is the most common usage for I<handles>. You basically pass a list of |
525 | method names to be delegated, and Moose will install a delegation method |
1cd45431 |
526 | for each one. |
38e3283b |
527 | |
528 | =item C<HASH> |
529 | |
26fbace8 |
530 | This is the second most common usage for I<handles>. Instead of a list of |
531 | method names, you pass a HASH ref where each key is the method name you |
532 | want installed locally, and its value is the name of the original method |
533 | in the class being delegated to. |
fd595040 |
534 | |
26fbace8 |
535 | This can be very useful for recursive classes like trees. Here is a |
fd595040 |
536 | quick example (soon to be expanded into a Moose::Cookbook::Recipe): |
38e3283b |
537 | |
1cd45431 |
538 | package Tree; |
38e3283b |
539 | use Moose; |
26fbace8 |
540 | |
38e3283b |
541 | has 'node' => (is => 'rw', isa => 'Any'); |
26fbace8 |
542 | |
38e3283b |
543 | has 'children' => ( |
544 | is => 'ro', |
545 | isa => 'ArrayRef', |
546 | default => sub { [] } |
547 | ); |
26fbace8 |
548 | |
38e3283b |
549 | has 'parent' => ( |
550 | is => 'rw', |
551 | isa => 'Tree', |
a4e516f6 |
552 | weak_ref => 1, |
38e3283b |
553 | handles => { |
554 | parent_node => 'node', |
26fbace8 |
555 | siblings => 'children', |
38e3283b |
556 | } |
557 | ); |
558 | |
1cd45431 |
559 | In this example, the Tree package gets C<parent_node> and C<siblings> methods, |
560 | which delegate to the C<node> and C<children> methods (respectively) of the Tree |
26fbace8 |
561 | instance stored in the C<parent> slot. |
38e3283b |
562 | |
563 | =item C<REGEXP> |
564 | |
26fbace8 |
565 | The regexp option works very similar to the ARRAY option, except that it builds |
566 | the list of methods for you. It starts by collecting all possible methods of the |
567 | class being delegated to, then filters that list using the regexp supplied here. |
38e3283b |
568 | |
26fbace8 |
569 | B<NOTE:> An I<isa> option is required when using the regexp option format. This |
570 | is so that we can determine (at compile time) the method list from the class. |
38e3283b |
571 | Without an I<isa> this is just not possible. |
572 | |
c84f324f |
573 | =item C<ROLE> |
574 | |
26fbace8 |
575 | With the role option, you specify the name of a role whose "interface" then |
576 | becomes the list of methods to handle. The "interface" can be defined as; the |
577 | methods of the role and any required methods of the role. It should be noted |
578 | that this does B<not> include any method modifiers or generated attribute |
c84f324f |
579 | methods (which is consistent with role composition). |
580 | |
38e3283b |
581 | =item C<CODE> |
582 | |
1cd45431 |
583 | This is the option to use when you really want to do something funky. You should |
584 | only use it if you really know what you are doing, as it involves manual |
585 | metaclass twiddling. |
38e3283b |
586 | |
1cd45431 |
587 | This takes a code reference, which should expect two arguments. The first is the |
588 | attribute meta-object this I<handles> is attached to. The second is the |
589 | metaclass of the class being delegated to. It expects you to return a hash (not |
26fbace8 |
590 | a HASH ref) of the methods you want mapped. |
38e3283b |
591 | |
592 | =back |
2c0cbef7 |
593 | |
004222dc |
594 | =item I<metaclass =E<gt> $metaclass_name> |
595 | |
596 | This tells the class to use a custom attribute metaclass for this particular |
597 | attribute. Custom attribute metaclasses are useful for extending the |
598 | capabilities of the I<has> keyword: they are the simplest way to extend the MOP, |
599 | but they are still a fairly advanced topic and too much to cover here, see |
600 | L<Moose::Cookbook::Recipe11> for more information. |
601 | |
602 | The default behavior here is to just load C<$metaclass_name>; however, we also |
603 | have a way to alias to a shorter name. This will first look to see if |
604 | B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose |
605 | will then check to see if that has the method C<register_implementation>, which |
606 | should return the actual name of the custom attribute metaclass. If there is no |
607 | C<register_implementation> method, it will fall back to using |
608 | B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name. |
609 | |
610 | =item I<traits =E<gt> [ @role_names ]> |
611 | |
612 | This tells Moose to take the list of C<@role_names> and apply them to the |
613 | attribute meta-object. This is very similar to the I<metaclass> option, but |
614 | allows you to use more than one extension at a time. This too is an advanced |
615 | topic, we don't yet have a cookbook for it though. |
616 | |
617 | As with I<metaclass>, the default behavior is to just load C<$role_name>; however, |
618 | we also have a way to alias to a shorter name. This will first look to see if |
619 | B<Moose::Meta::Attribute::Custom::Trait::$role_name> exists. If it does, Moose |
620 | will then check to see if that has the method C<register_implementation>, which |
621 | should return the actual name of the custom attribute trait. If there is no |
622 | C<register_implementation> method, it will fall back to using |
623 | B<Moose::Meta::Attribute::Custom::Trait::$metaclass_name> as the trait name. |
624 | |
6ba6d68c |
625 | =back |
626 | |
cd7eeaf5 |
627 | =item B<has +$name =E<gt> %options> |
628 | |
26fbace8 |
629 | This is variation on the normal attibute creator C<has> which allows you to |
8d62bf6d |
630 | clone and extend an attribute from a superclass or from a role. Here is an |
631 | example of the superclass usage: |
cd7eeaf5 |
632 | |
633 | package Foo; |
634 | use Moose; |
26fbace8 |
635 | |
cd7eeaf5 |
636 | has 'message' => ( |
26fbace8 |
637 | is => 'rw', |
cd7eeaf5 |
638 | isa => 'Str', |
639 | default => 'Hello, I am a Foo' |
640 | ); |
26fbace8 |
641 | |
cd7eeaf5 |
642 | package My::Foo; |
643 | use Moose; |
26fbace8 |
644 | |
cd7eeaf5 |
645 | extends 'Foo'; |
26fbace8 |
646 | |
cd7eeaf5 |
647 | has '+message' => (default => 'Hello I am My::Foo'); |
648 | |
1cd45431 |
649 | What is happening here is that B<My::Foo> is cloning the C<message> attribute |
650 | from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt> |
651 | 'Str'> characteristics, but changing the value in C<default>. |
cd7eeaf5 |
652 | |
8d62bf6d |
653 | Here is another example, but within the context of a role: |
654 | |
655 | package Foo::Role; |
656 | use Moose::Role; |
657 | |
658 | has 'message' => ( |
659 | is => 'rw', |
660 | isa => 'Str', |
661 | default => 'Hello, I am a Foo' |
662 | ); |
663 | |
664 | package My::Foo; |
665 | use Moose; |
666 | |
667 | with 'Foo::Role'; |
668 | |
669 | has '+message' => (default => 'Hello I am My::Foo'); |
670 | |
671 | In this case, we are basically taking the attribute which the role supplied |
4032c9bb |
672 | and altering it within the bounds of this feature. |
8d62bf6d |
673 | |
4032c9bb |
674 | Aside from where the attributes come from (one from superclass, the other |
675 | from a role), this feature works exactly the same. This feature is restricted |
676 | somewhat, so as to try and force at least I<some> sanity into it. You are only |
677 | allowed to change the following attributes: |
cd7eeaf5 |
678 | |
679 | =over 4 |
680 | |
26fbace8 |
681 | =item I<default> |
cd7eeaf5 |
682 | |
683 | Change the default value of an attribute. |
684 | |
26fbace8 |
685 | =item I<coerce> |
cd7eeaf5 |
686 | |
687 | Change whether the attribute attempts to coerce a value passed to it. |
688 | |
26fbace8 |
689 | =item I<required> |
cd7eeaf5 |
690 | |
691 | Change if the attribute is required to have a value. |
692 | |
693 | =item I<documentation> |
694 | |
695 | Change the documentation string associated with the attribute. |
696 | |
83cc9094 |
697 | =item I<lazy> |
698 | |
699 | Change if the attribute lazily initializes the slot. |
700 | |
cd7eeaf5 |
701 | =item I<isa> |
702 | |
aed87761 |
703 | You I<are> allowed to change the type without restriction. |
704 | |
705 | It is recommended that you use this freedom with caution. We used to |
706 | only allow for extension only if the type was a subtype of the parent's |
707 | type, but we felt that was too restrictive and is better left as a |
708 | policy descision. |
cd7eeaf5 |
709 | |
83cc9094 |
710 | =item I<handles> |
711 | |
26fbace8 |
712 | You are allowed to B<add> a new C<handles> definition, but you are B<not> |
713 | allowed to I<change> one. |
83cc9094 |
714 | |
8d62bf6d |
715 | =item I<builder> |
716 | |
717 | You are allowed to B<add> a new C<builder> definition, but you are B<not> |
718 | allowed to I<change> one. |
719 | |
cd7eeaf5 |
720 | =back |
721 | |
076c81ed |
722 | =item B<before $name|@names =E<gt> sub { ... }> |
6ba6d68c |
723 | |
076c81ed |
724 | =item B<after $name|@names =E<gt> sub { ... }> |
6ba6d68c |
725 | |
076c81ed |
726 | =item B<around $name|@names =E<gt> sub { ... }> |
6ba6d68c |
727 | |
d8af92ae |
728 | This three items are syntactic sugar for the before, after, and around method |
729 | modifier features that L<Class::MOP> provides. More information on these may be |
730 | found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method |
731 | Modifiers"> for now. |
6ba6d68c |
732 | |
159da176 |
733 | =item B<super> |
734 | |
26fbace8 |
735 | The keyword C<super> is a no-op when called outside of an C<override> method. In |
736 | the context of an C<override> method, it will call the next most appropriate |
159da176 |
737 | superclass method with the same arguments as the original method. |
738 | |
739 | =item B<override ($name, &sub)> |
740 | |
26fbace8 |
741 | An C<override> method is a way of explicitly saying "I am overriding this |
742 | method from my superclass". You can call C<super> within this method, and |
743 | it will work as expected. The same thing I<can> be accomplished with a normal |
744 | method call and the C<SUPER::> pseudo-package; it is really your choice. |
159da176 |
745 | |
746 | =item B<inner> |
747 | |
26fbace8 |
748 | The keyword C<inner>, much like C<super>, is a no-op outside of the context of |
749 | an C<augment> method. You can think of C<inner> as being the inverse of |
68efb014 |
750 | C<super>; the details of how C<inner> and C<augment> work is best described in |
004222dc |
751 | the L<Moose::Cookbook::Recipe7>. |
159da176 |
752 | |
753 | =item B<augment ($name, &sub)> |
754 | |
26fbace8 |
755 | An C<augment> method, is a way of explicitly saying "I am augmenting this |
756 | method from my superclass". Once again, the details of how C<inner> and |
004222dc |
757 | C<augment> work is best described in the L<Moose::Cookbook::Recipe7>. |
159da176 |
758 | |
6ba6d68c |
759 | =item B<confess> |
760 | |
68efb014 |
761 | This is the C<Carp::confess> function, and exported here because I use it |
004222dc |
762 | all the time. |
6ba6d68c |
763 | |
764 | =item B<blessed> |
765 | |
1cd45431 |
766 | This is the C<Scalar::Util::blessed> function, it is exported here because I |
26fbace8 |
767 | use it all the time. It is highly recommended that this is used instead of |
6ba6d68c |
768 | C<ref> anywhere you need to test for an object's class name. |
769 | |
770 | =back |
771 | |
1cd45431 |
772 | =head1 UNIMPORTING FUNCTIONS |
31f8ec72 |
773 | |
774 | =head2 B<unimport> |
775 | |
1cd45431 |
776 | Moose offers a way to remove the keywords it exports, through the C<unimport> |
31f8ec72 |
777 | method. You simply have to say C<no Moose> at the bottom of your code for this |
778 | to work. Here is an example: |
779 | |
780 | package Person; |
781 | use Moose; |
782 | |
783 | has 'first_name' => (is => 'rw', isa => 'Str'); |
784 | has 'last_name' => (is => 'rw', isa => 'Str'); |
26fbace8 |
785 | |
786 | sub full_name { |
31f8ec72 |
787 | my $self = shift; |
26fbace8 |
788 | $self->first_name . ' ' . $self->last_name |
31f8ec72 |
789 | } |
26fbace8 |
790 | |
791 | no Moose; # keywords are removed from the Person package |
31f8ec72 |
792 | |
9bcfbab1 |
793 | =head1 EXTENDING AND EMBEDDING MOOSE |
794 | |
26fbace8 |
795 | Moose also offers some options for extending or embedding it into your own |
9bcfbab1 |
796 | framework. The basic premise is to have something that sets up your class' |
26fbace8 |
797 | metaclass and export the moose declarators (C<has>, C<with>, C<extends>,...). |
9bcfbab1 |
798 | Here is an example: |
799 | |
800 | package MyFramework; |
801 | use Moose; |
26fbace8 |
802 | |
9bcfbab1 |
803 | sub import { |
804 | my $CALLER = caller(); |
805 | |
806 | strict->import; |
807 | warnings->import; |
808 | |
809 | # we should never export to main |
810 | return if $CALLER eq 'main'; |
811 | Moose::init_meta( $CALLER, 'MyFramework::Base' ); |
812 | Moose->import({into => $CALLER}); |
813 | |
814 | # Do my custom framework stuff |
26fbace8 |
815 | |
9bcfbab1 |
816 | return 1; |
817 | } |
26fbace8 |
818 | |
9bcfbab1 |
819 | =head2 B<import> |
820 | |
77a18c28 |
821 | Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}> |
9bcfbab1 |
822 | and C<{into_level =E<gt> 1}> |
823 | |
824 | =head2 B<init_meta ($class, $baseclass, $metaclass)> |
825 | |
26fbace8 |
826 | Moose does some boot strapping: it creates a metaclass object for your class, |
827 | and then injects a C<meta> accessor into your class to retrieve it. Then it |
828 | sets your baseclass to Moose::Object or the value you pass in unless you already |
829 | have one. This is all done via C<init_meta> which takes the name of your class |
2bbba362 |
830 | and optionally a baseclass and a metaclass as arguments. |
26fbace8 |
831 | |
05d9eaf6 |
832 | =head1 CAVEATS |
833 | |
834 | =over 4 |
835 | |
836 | =item * |
837 | |
1cd45431 |
838 | It should be noted that C<super> and C<inner> B<cannot> be used in the same |
839 | method. However, they may be combined within the same class hierarchy; see |
840 | F<t/014_override_augment_inner_super.t> for an example. |
05d9eaf6 |
841 | |
26fbace8 |
842 | The reason for this is that C<super> is only valid within a method |
843 | with the C<override> modifier, and C<inner> will never be valid within an |
844 | C<override> method. In fact, C<augment> will skip over any C<override> methods |
68efb014 |
845 | when searching for its appropriate C<inner>. |
05d9eaf6 |
846 | |
1cd45431 |
847 | This might seem like a restriction, but I am of the opinion that keeping these |
848 | two features separate (yet interoperable) actually makes them easy to use, since |
849 | their behavior is then easier to predict. Time will tell whether I am right or |
c84f324f |
850 | not (UPDATE: so far so good). |
05d9eaf6 |
851 | |
004222dc |
852 | =item * |
853 | |
854 | It is important to note that we currently have no simple way of combining |
855 | multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above), |
856 | and that in many cases they will conflict with one another. We are working on |
857 | developing a way around this issue, but in the meantime, you have been warned. |
858 | |
05d9eaf6 |
859 | =back |
860 | |
5569c072 |
861 | =head1 ACKNOWLEDGEMENTS |
862 | |
863 | =over 4 |
864 | |
54c189df |
865 | =item I blame Sam Vilain for introducing me to the insanity that is meta-models. |
5569c072 |
866 | |
54c189df |
867 | =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6. |
5569c072 |
868 | |
26fbace8 |
869 | =item Without Yuval "nothingmuch" Kogman this module would not be possible, |
54c189df |
870 | and it certainly wouldn't have this name ;P |
5569c072 |
871 | |
26fbace8 |
872 | =item The basis of the TypeContraints module was Rob Kinyon's idea |
5569c072 |
873 | originally, I just ran with it. |
874 | |
638585e1 |
875 | =item Thanks to mst & chansen and the whole #moose posse for all the |
c84f324f |
876 | early ideas/feature-requests/encouragement/bug-finding. |
d46a48f3 |
877 | |
68efb014 |
878 | =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes. |
879 | |
5569c072 |
880 | =back |
881 | |
e90c03d0 |
882 | =head1 SEE ALSO |
883 | |
884 | =over 4 |
885 | |
c84f324f |
886 | =item L<http://www.iinteractive.com/moose> |
887 | |
888 | This is the official web home of Moose, it contains links to our public SVN repo |
26fbace8 |
889 | as well as links to a number of talks and articles on Moose and Moose related |
890 | technologies. |
c84f324f |
891 | |
6ba6d68c |
892 | =item L<Class::MOP> documentation |
893 | |
894 | =item The #moose channel on irc.perl.org |
895 | |
e67a0fca |
896 | =item The Moose mailing list - moose@perl.org |
897 | |
c84f324f |
898 | =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/5788> |
899 | |
28669f89 |
900 | =item Several Moose extension modules in the L<MooseX::> namespace. |
901 | |
c84f324f |
902 | =back |
903 | |
004222dc |
904 | =head2 Books |
905 | |
906 | =over 4 |
907 | |
908 | =item The Art of the MetaObject Protocol |
909 | |
910 | I mention this in the L<Class::MOP> docs too, this book was critical in |
911 | the development of both modules and is highly recommended. |
912 | |
913 | =back |
914 | |
26fbace8 |
915 | =head2 Papers |
c84f324f |
916 | |
917 | =over 4 |
e90c03d0 |
918 | |
159da176 |
919 | =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf> |
920 | |
26fbace8 |
921 | This paper (suggested by lbr on #moose) was what lead to the implementation |
922 | of the C<super>/C<override> and C<inner>/C<augment> features. If you really |
1cd45431 |
923 | want to understand them, I suggest you read this. |
159da176 |
924 | |
e90c03d0 |
925 | =back |
926 | |
fcd84ca9 |
927 | =head1 BUGS |
928 | |
26fbace8 |
929 | All complex software has bugs lurking in it, and this module is no |
fcd84ca9 |
930 | exception. If you find a bug please either email me, or add the bug |
931 | to cpan-RT. |
932 | |
fcd84ca9 |
933 | =head1 AUTHOR |
934 | |
935 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
936 | |
9af1d28b |
937 | B<with contributions from:> |
db1ab48d |
938 | |
9af1d28b |
939 | Aankhen |
940 | |
941 | Adam (Alias) Kennedy |
942 | |
943 | Anders (Debolaz) Nor Berle |
944 | |
5868294f |
945 | Nathan (kolibre) Gray |
946 | |
9af1d28b |
947 | Christian (chansen) Hansen |
948 | |
e7f8d0c2 |
949 | Hans Dieter (confound) Pearcey |
950 | |
9af1d28b |
951 | Eric (ewilhelm) Wilhelm |
952 | |
953 | Guillermo (groditi) Roditi |
954 | |
955 | Jess (castaway) Robinson |
956 | |
957 | Matt (mst) Trout |
958 | |
959 | Robert (phaylon) Sedlacek |
960 | |
961 | Robert (rlb3) Boone |
962 | |
963 | Scott (konobi) McWhirter |
964 | |
f44ae52f |
965 | Shlomi (rindolf) Fish |
966 | |
9af1d28b |
967 | Yuval (nothingmuch) Kogman |
968 | |
cbe25729 |
969 | Chris (perigrin) Prather |
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 |