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; |
7c13858b |
20 | use Moose::Meta::TypeCoercion; |
78cd1d3b |
21 | use Moose::Meta::Attribute; |
ddd0ec20 |
22 | use Moose::Meta::Instance; |
c0e30cf5 |
23 | |
d67145ed |
24 | use Moose::Meta::Role; |
25 | |
fcd84ca9 |
26 | use Moose::Object; |
7415b2cb |
27 | use Moose::Util::TypeConstraints; |
d7d8a8c7 |
28 | use Moose::Util (); |
a15dff8d |
29 | |
a3c7e2fe |
30 | { |
be33e4f3 |
31 | my $CALLER; |
9bcfbab1 |
32 | |
33 | sub init_meta { |
34 | my ( $class, $base_class, $metaclass ) = @_; |
688fcdda |
35 | $base_class = 'Moose::Object' unless defined $base_class; |
36 | $metaclass = 'Moose::Meta::Class' unless defined $metaclass; |
9bcfbab1 |
37 | |
38 | confess |
97e11ef5 |
39 | "The Metaclass $metaclass must be a subclass of Moose::Meta::Class." |
40 | unless $metaclass->isa('Moose::Meta::Class'); |
a3c7e2fe |
41 | |
a3c7e2fe |
42 | # make a subtype for each Moose class |
3fef8ce8 |
43 | class_type($class) |
44 | unless find_type_constraint($class); |
a3c7e2fe |
45 | |
46 | my $meta; |
9bcfbab1 |
47 | if ( $class->can('meta') ) { |
fcec2383 |
48 | # NOTE: |
9bcfbab1 |
49 | # this is the case where the metaclass pragma |
50 | # was used before the 'use Moose' statement to |
fcec2383 |
51 | # override a specific class |
a3c7e2fe |
52 | $meta = $class->meta(); |
9bcfbab1 |
53 | ( blessed($meta) && $meta->isa('Moose::Meta::Class') ) |
1edfdf1c |
54 | || confess "You already have a &meta function, but it does not return a Moose::Meta::Class"; |
a3c7e2fe |
55 | } |
56 | else { |
fcec2383 |
57 | # NOTE: |
9bcfbab1 |
58 | # this is broken currently, we actually need |
59 | # to allow the possiblity of an inherited |
60 | # meta, which will not be visible until the |
61 | # user 'extends' first. This needs to have |
62 | # more intelligence to it |
63 | $meta = $metaclass->initialize($class); |
64 | $meta->add_method( |
65 | 'meta' => sub { |
9bcfbab1 |
66 | # re-initialize so it inherits properly |
67 | $metaclass->initialize( blessed( $_[0] ) || $_[0] ); |
68 | } |
69 | ); |
a3c7e2fe |
70 | } |
71 | |
72 | # make sure they inherit from Moose::Object |
72bbc189 |
73 | $meta->superclasses($base_class) |
9bcfbab1 |
74 | unless $meta->superclasses(); |
688fcdda |
75 | |
76 | return $meta; |
a3c7e2fe |
77 | } |
78 | |
79 | my %exports = ( |
80 | extends => sub { |
be33e4f3 |
81 | my $class = $CALLER; |
68117c45 |
82 | return subname 'Moose::extends' => sub (@) { |
83 | confess "Must derive at least one class" unless @_; |
9c10b5ad |
84 | |
85 | my @supers = @_; |
86 | foreach my $super (@supers) { |
87 | Class::MOP::load_class($super); |
88 | } |
9bcfbab1 |
89 | |
90 | # this checks the metaclass to make sure |
91 | # it is correct, sometimes it can get out |
1341f10c |
92 | # of sync when the classes are being built |
9c10b5ad |
93 | my $meta = $class->meta->_fix_metaclass_incompatability(@supers); |
94 | $meta->superclasses(@supers); |
a3c7e2fe |
95 | }; |
96 | }, |
97 | with => sub { |
be33e4f3 |
98 | my $class = $CALLER; |
68117c45 |
99 | return subname 'Moose::with' => sub (@) { |
d7d8a8c7 |
100 | Moose::Util::apply_all_roles($class->meta, @_) |
a3c7e2fe |
101 | }; |
102 | }, |
103 | has => sub { |
be33e4f3 |
104 | my $class = $CALLER; |
2c0cbef7 |
105 | return subname 'Moose::has' => sub ($;%) { |
a28fe77b |
106 | my $name = shift; |
547dda77 |
107 | croak 'Usage: has \'name\' => ( key => value, ... )' if @_ == 1; |
a28fe77b |
108 | my %options = @_; |
9bcfbab1 |
109 | my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ]; |
d7d8a8c7 |
110 | $class->meta->add_attribute( $_, %options ) for @$attrs; |
a3c7e2fe |
111 | }; |
112 | }, |
113 | before => sub { |
be33e4f3 |
114 | my $class = $CALLER; |
2c0cbef7 |
115 | return subname 'Moose::before' => sub (@&) { |
a3c7e2fe |
116 | my $code = pop @_; |
be33e4f3 |
117 | my $meta = $class->meta; |
9bcfbab1 |
118 | $meta->add_before_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
119 | }; |
120 | }, |
121 | after => sub { |
be33e4f3 |
122 | my $class = $CALLER; |
2c0cbef7 |
123 | return subname 'Moose::after' => sub (@&) { |
a3c7e2fe |
124 | my $code = pop @_; |
be33e4f3 |
125 | my $meta = $class->meta; |
9bcfbab1 |
126 | $meta->add_after_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
127 | }; |
128 | }, |
129 | around => sub { |
9bcfbab1 |
130 | my $class = $CALLER; |
2c0cbef7 |
131 | return subname 'Moose::around' => sub (@&) { |
a3c7e2fe |
132 | my $code = pop @_; |
be33e4f3 |
133 | my $meta = $class->meta; |
9bcfbab1 |
134 | $meta->add_around_method_modifier( $_, $code ) for @_; |
a3c7e2fe |
135 | }; |
136 | }, |
137 | super => sub { |
52c7c330 |
138 | { |
9bcfbab1 |
139 | our %SUPER_SLOT; |
140 | no strict 'refs'; |
141 | $SUPER_SLOT{$CALLER} = \*{"${CALLER}::super"}; |
52c7c330 |
142 | } |
9bcfbab1 |
143 | return subname 'Moose::super' => sub { }; |
a3c7e2fe |
144 | }, |
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 { |
52c7c330 |
153 | { |
9bcfbab1 |
154 | our %INNER_SLOT; |
155 | no strict 'refs'; |
156 | $INNER_SLOT{$CALLER} = \*{"${CALLER}::inner"}; |
52c7c330 |
157 | } |
9bcfbab1 |
158 | return subname 'Moose::inner' => sub { }; |
a3c7e2fe |
159 | }, |
160 | augment => sub { |
be33e4f3 |
161 | my $class = $CALLER; |
2c0cbef7 |
162 | return subname 'Moose::augment' => sub (@&) { |
9bcfbab1 |
163 | my ( $name, $method ) = @_; |
164 | $class->meta->add_augment_method_modifier( $name => $method ); |
a3c7e2fe |
165 | }; |
166 | }, |
2a5e59d0 |
167 | make_immutable => sub { |
168 | my $class = $CALLER; |
169 | return subname 'Moose::make_immutable' => sub { |
c2922d69 |
170 | warn "The make_immutable keyword has been deprecated, " . |
171 | "please go back to __PACKAGE__->meta->make_immutable\n"; |
e902b1a5 |
172 | $class->meta->make_immutable(@_); |
2a5e59d0 |
173 | }; |
174 | }, |
a3c7e2fe |
175 | confess => sub { |
176 | return \&Carp::confess; |
177 | }, |
178 | blessed => sub { |
179 | return \&Scalar::Util::blessed; |
66bcefc1 |
180 | }, |
a3c7e2fe |
181 | ); |
3d544ed5 |
182 | |
9bcfbab1 |
183 | my $exporter = Sub::Exporter::build_exporter( |
184 | { |
185 | exports => \%exports, |
186 | groups => { default => [':all'] } |
a3c7e2fe |
187 | } |
9bcfbab1 |
188 | ); |
189 | |
c92c1205 |
190 | # 1 extra level because it's called by import so there's a layer of indirection |
191 | sub _get_caller{ |
192 | my $offset = 1; |
26fbace8 |
193 | return |
c92c1205 |
194 | ref $_[1] && defined $_[1]->{into} |
195 | ? $_[1]->{into} |
196 | : ref $_[1] && defined $_[1]->{into_level} |
197 | ? caller($offset + $_[1]->{into_level}) |
198 | : caller($offset); |
199 | } |
5bee491d |
200 | |
201 | sub import { |
c92c1205 |
202 | $CALLER = _get_caller(@_); |
26fbace8 |
203 | |
86dd5d11 |
204 | # this works because both pragmas set $^H (see perldoc perlvar) |
205 | # which affects the current compilation - i.e. the file who use'd |
206 | # us - which is why we don't need to do anything special to make |
207 | # it affect that file rather than this one (which is already compiled) |
208 | |
c235cd98 |
209 | strict->import; |
9bcfbab1 |
210 | warnings->import; |
a3c7e2fe |
211 | |
212 | # we should never export to main |
213 | return if $CALLER eq 'main'; |
9bcfbab1 |
214 | |
215 | init_meta( $CALLER, 'Moose::Object' ); |
216 | |
a3c7e2fe |
217 | goto $exporter; |
fcb7afc2 |
218 | } |
9bcfbab1 |
219 | |
31f8ec72 |
220 | sub unimport { |
9bcfbab1 |
221 | no strict 'refs'; |
c92c1205 |
222 | my $class = _get_caller(@_); |
9bcfbab1 |
223 | |
31f8ec72 |
224 | # loop through the exports ... |
9bcfbab1 |
225 | foreach my $name ( keys %exports ) { |
226 | |
31f8ec72 |
227 | # if we find one ... |
9bcfbab1 |
228 | if ( defined &{ $class . '::' . $name } ) { |
229 | my $keyword = \&{ $class . '::' . $name }; |
230 | |
31f8ec72 |
231 | # make sure it is from Moose |
53dd42d8 |
232 | my ($pkg_name) = Class::MOP::get_code_info($keyword); |
31f8ec72 |
233 | next if $@; |
234 | next if $pkg_name ne 'Moose'; |
9bcfbab1 |
235 | |
31f8ec72 |
236 | # and if it is from Moose then undef the slot |
9bcfbab1 |
237 | delete ${ $class . '::' }{$name}; |
31f8ec72 |
238 | } |
239 | } |
240 | } |
9bcfbab1 |
241 | |
fcd84ca9 |
242 | } |
243 | |
8ecb1fa0 |
244 | ## make 'em all immutable |
245 | |
246 | $_->meta->make_immutable( |
247 | inline_constructor => 0, |
77a18c28 |
248 | inline_accessors => 1, # these are Class::MOP accessors, so they need inlining |
9bcfbab1 |
249 | ) |
250 | for ( |
8ecb1fa0 |
251 | 'Moose::Meta::Attribute', |
252 | 'Moose::Meta::Class', |
253 | 'Moose::Meta::Instance', |
254 | |
255 | 'Moose::Meta::TypeConstraint', |
256 | 'Moose::Meta::TypeConstraint::Union', |
0fbd4b0a |
257 | 'Moose::Meta::TypeConstraint::Parameterized', |
8ecb1fa0 |
258 | 'Moose::Meta::TypeCoercion', |
259 | |
260 | 'Moose::Meta::Method', |
261 | 'Moose::Meta::Method::Accessor', |
262 | 'Moose::Meta::Method::Constructor', |
9bcfbab1 |
263 | 'Moose::Meta::Method::Destructor', |
8ecb1fa0 |
264 | 'Moose::Meta::Method::Overriden', |
d67145ed |
265 | |
266 | 'Moose::Meta::Role', |
9bcfbab1 |
267 | 'Moose::Meta::Role::Method', |
268 | 'Moose::Meta::Role::Method::Required', |
269 | ); |
8ecb1fa0 |
270 | |
fcd84ca9 |
271 | 1; |
272 | |
273 | __END__ |
274 | |
275 | =pod |
276 | |
277 | =head1 NAME |
278 | |
8bdc7f13 |
279 | Moose - A postmodern object system for Perl 5 |
fcd84ca9 |
280 | |
281 | =head1 SYNOPSIS |
e522431d |
282 | |
283 | package Point; |
1cd45431 |
284 | use Moose; # automatically turns on strict and warnings |
26fbace8 |
285 | |
43d599e5 |
286 | has 'x' => (is => 'rw', isa => 'Int'); |
287 | has 'y' => (is => 'rw', isa => 'Int'); |
26fbace8 |
288 | |
e522431d |
289 | sub clear { |
290 | my $self = shift; |
291 | $self->x(0); |
26fbace8 |
292 | $self->y(0); |
e522431d |
293 | } |
26fbace8 |
294 | |
e522431d |
295 | package Point3D; |
296 | use Moose; |
26fbace8 |
297 | |
e522431d |
298 | extends 'Point'; |
26fbace8 |
299 | |
43d599e5 |
300 | has 'z' => (is => 'rw', isa => 'Int'); |
26fbace8 |
301 | |
e522431d |
302 | after 'clear' => sub { |
303 | my $self = shift; |
43d599e5 |
304 | $self->z(0); |
26fbace8 |
305 | }; |
2c0cbef7 |
306 | |
fcd84ca9 |
307 | =head1 DESCRIPTION |
308 | |
26fbace8 |
309 | Moose is an extension of the Perl 5 object system. |
e522431d |
310 | |
311 | =head2 Another object system!?!? |
fcd84ca9 |
312 | |
26fbace8 |
313 | Yes, I know there has been an explosion recently of new ways to |
68efb014 |
314 | build object's in Perl 5, most of them based on inside-out objects |
26fbace8 |
315 | and other such things. Moose is different because it is not a new |
316 | object system for Perl 5, but instead an extension of the existing |
e522431d |
317 | object system. |
3c7278fb |
318 | |
26fbace8 |
319 | Moose is built on top of L<Class::MOP>, which is a metaclass system |
320 | for Perl 5. This means that Moose not only makes building normal |
321 | Perl 5 objects better, but it also provides the power of metaclass |
505c6fac |
322 | programming. |
e522431d |
323 | |
734d1752 |
324 | =head2 Is this for real? Or is this just an experiment? |
e522431d |
325 | |
2c0cbef7 |
326 | Moose is I<based> on the prototypes and experiments I did for the Perl 6 |
26fbace8 |
327 | meta-model. However, Moose is B<NOT> an experiment/prototype; it is for B<real>. |
734d1752 |
328 | |
26fbace8 |
329 | =head2 Is this ready for use in production? |
d44714be |
330 | |
26fbace8 |
331 | Yes, I believe that it is. |
734d1752 |
332 | |
26fbace8 |
333 | Moose has been used successfully in production environemnts by several people |
334 | and companies (including the one I work for). There are Moose applications |
8bdc7f13 |
335 | which have been in production with little or no issue now for well over a year. |
26fbace8 |
336 | I consider it highly stable and we are commited to keeping it stable. |
e522431d |
337 | |
26fbace8 |
338 | Of course, in the end, you need to make this call yourself. If you have |
339 | any questions or concerns, please feel free to email me, or even the list |
d44714be |
340 | or just stop by #moose and ask away. |
341 | |
43d599e5 |
342 | =head2 Is Moose just Perl 6 in Perl 5? |
e522431d |
343 | |
68efb014 |
344 | No. While Moose is very much inspired by Perl 6, it is not itself Perl 6. |
1cd45431 |
345 | Instead, it is an OO system for Perl 5. I built Moose because I was tired of |
68efb014 |
346 | writing the same old boring Perl 5 OO code, and drooling over Perl 6 OO. So |
347 | instead of switching to Ruby, I wrote Moose :) |
3c7278fb |
348 | |
8bdc7f13 |
349 | =head2 Wait, I<post> modern, I thought it was just I<modern>? |
350 | |
351 | So I was reading Larry Wall's talk from the 1999 Linux World entitled |
352 | "Perl, the first postmodern computer language" in which he talks about how |
353 | he picked the features for Perl because he thought they were cool and he |
354 | threw out the ones that he thought sucked. This got me thinking about how |
355 | we have done the same thing in Moose. For Moose, we have "borrowed" features |
356 | from Perl 6, CLOS (LISP), Smalltalk, Java, BETA, OCaml, Ruby and more, and |
357 | the bits we didn't like (cause they sucked) we tossed aside. So for this |
358 | reason (and a few others) I have re-dubbed Moose a I<postmodern> object system. |
359 | |
360 | Nuff Said. |
361 | |
28669f89 |
362 | =head2 Moose Extensions |
363 | |
364 | The L<MooseX::> namespace is the official place to find Moose extensions. |
0b26305c |
365 | There are a number of these modules out on CPAN right now the best way to |
366 | find them is to search for MooseX:: on search.cpan.org. |
28669f89 |
367 | |
6ba6d68c |
368 | =head1 BUILDING CLASSES WITH MOOSE |
369 | |
68efb014 |
370 | Moose makes every attempt to provide as much convenience as possible during |
371 | class construction/definition, but still stay out of your way if you want it |
372 | to. Here are a few items to note when building classes with Moose. |
6ba6d68c |
373 | |
26fbace8 |
374 | Unless specified with C<extends>, any class which uses Moose will |
6ba6d68c |
375 | inherit from L<Moose::Object>. |
376 | |
1cd45431 |
377 | Moose will also manage all attributes (including inherited ones) that are |
378 | defined with C<has>. And (assuming you call C<new>, which is inherited from |
379 | L<Moose::Object>) this includes properly initializing all instance slots, |
380 | setting defaults where appropriate, and performing any type constraint checking |
381 | or coercion. |
6ba6d68c |
382 | |
004222dc |
383 | =head1 PROVIDED METHODS |
6ba6d68c |
384 | |
004222dc |
385 | Moose provides a number of methods to all your classes, mostly through the |
386 | inheritance of L<Moose::Object>. There is however, one exception. |
6ba6d68c |
387 | |
388 | =over 4 |
389 | |
390 | =item B<meta> |
391 | |
392 | This is a method which provides access to the current class's metaclass. |
393 | |
004222dc |
394 | =back |
395 | |
396 | =head1 EXPORTED FUNCTIONS |
397 | |
398 | Moose will export a number of functions into the class's namespace which |
399 | may then be used to set up the class. These functions all work directly |
400 | on the current class. |
401 | |
402 | =over 4 |
403 | |
6ba6d68c |
404 | =item B<extends (@superclasses)> |
405 | |
406 | This function will set the superclass(es) for the current class. |
407 | |
26fbace8 |
408 | This approach is recommended instead of C<use base>, because C<use base> |
409 | actually C<push>es onto the class's C<@ISA>, whereas C<extends> will |
410 | replace it. This is important to ensure that classes which do not have |
68efb014 |
411 | superclasses still properly inherit from L<Moose::Object>. |
6ba6d68c |
412 | |
43d599e5 |
413 | =item B<with (@roles)> |
e9ec68d6 |
414 | |
004222dc |
415 | This will apply a given set of C<@roles> to the local class. |
e9ec68d6 |
416 | |
cd7eeaf5 |
417 | =item B<has $name =E<gt> %options> |
6ba6d68c |
418 | |
26fbace8 |
419 | This will install an attribute of a given C<$name> into the current class. |
420 | The C<%options> are the same as those provided by |
421 | L<Class::MOP::Attribute>, in addition to the list below which are provided |
43d599e5 |
422 | by Moose (L<Moose::Meta::Attribute> to be more specific): |
6ba6d68c |
423 | |
424 | =over 4 |
425 | |
076c81ed |
426 | =item I<is =E<gt> 'rw'|'ro'> |
6ba6d68c |
427 | |
26fbace8 |
428 | The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read |
429 | only). These will create either a read/write accessor or a read-only |
6ba6d68c |
430 | accessor respectively, using the same name as the C<$name> of the attribute. |
431 | |
1cd45431 |
432 | If you need more control over how your accessors are named, you can use the |
433 | I<reader>, I<writer> and I<accessor> options inherited from |
004222dc |
434 | L<Class::MOP::Attribute>, however if you use those, you won't need the I<is> |
435 | option. |
6ba6d68c |
436 | |
076c81ed |
437 | =item I<isa =E<gt> $type_name> |
6ba6d68c |
438 | |
26fbace8 |
439 | The I<isa> option uses Moose's type constraint facilities to set up runtime |
440 | type checking for this attribute. Moose will perform the checks during class |
441 | construction, and within any accessors. The C<$type_name> argument must be a |
442 | string. The string may be either a class name or a type defined using |
9cca2e9e |
443 | Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints> |
c2a69ef1 |
444 | for information on how to define a new type, and how to retrieve type meta-data). |
6ba6d68c |
445 | |
daea75c9 |
446 | =item I<coerce =E<gt> (1|0)> |
447 | |
26fbace8 |
448 | This will attempt to use coercion with the supplied type constraint to change |
449 | the value passed into any accessors or constructors. You B<must> have supplied |
daea75c9 |
450 | a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5> |
1cd45431 |
451 | for an example. |
daea75c9 |
452 | |
453 | =item I<does =E<gt> $role_name> |
454 | |
26fbace8 |
455 | This will accept the name of a role which the value stored in this attribute |
daea75c9 |
456 | is expected to have consumed. |
457 | |
458 | =item I<required =E<gt> (1|0)> |
459 | |
26fbace8 |
460 | This marks the attribute as being required. This means a I<defined> value must be |
461 | supplied during class construction, and the attribute may never be set to |
462 | C<undef> with an accessor. |
daea75c9 |
463 | |
464 | =item I<weak_ref =E<gt> (1|0)> |
465 | |
68efb014 |
466 | This will tell the class to store the value of this attribute as a weakened |
467 | reference. If an attribute is a weakened reference, it B<cannot> also be |
468 | coerced. |
daea75c9 |
469 | |
470 | =item I<lazy =E<gt> (1|0)> |
471 | |
26fbace8 |
472 | This will tell the class to not create this slot until absolutely necessary. |
daea75c9 |
473 | If an attribute is marked as lazy it B<must> have a default supplied. |
474 | |
9e93dd19 |
475 | =item I<auto_deref =E<gt> (1|0)> |
476 | |
26fbace8 |
477 | This tells the accessor whether to automatically dereference the value returned. |
1cd45431 |
478 | This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>. |
9e93dd19 |
479 | |
daea75c9 |
480 | =item I<trigger =E<gt> $code> |
481 | |
1cd45431 |
482 | The I<trigger> option is a CODE reference which will be called after the value of |
483 | the attribute is set. The CODE ref will be passed the instance itself, the |
daea75c9 |
484 | updated value and the attribute meta-object (this is for more advanced fiddling |
1cd45431 |
485 | and can typically be ignored). You B<cannot> have a trigger on a read-only |
486 | attribute. |
daea75c9 |
487 | |
c84f324f |
488 | =item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE> |
2c0cbef7 |
489 | |
26fbace8 |
490 | The I<handles> option provides Moose classes with automated delegation features. |
491 | This is a pretty complex and powerful option. It accepts many different option |
492 | formats, each with its own benefits and drawbacks. |
38e3283b |
493 | |
1cd45431 |
494 | B<NOTE:> The class being delegated to does not need to be a Moose based class, |
495 | which is why this feature is especially useful when wrapping non-Moose classes. |
38e3283b |
496 | |
1cd45431 |
497 | All I<handles> option formats share the following traits: |
38e3283b |
498 | |
1cd45431 |
499 | You cannot override a locally defined method with a delegated method; an |
500 | exception will be thrown if you try. That is to say, if you define C<foo> in |
501 | your class, you cannot override it with a delegated C<foo>. This is almost never |
502 | something you would want to do, and if it is, you should do it by hand and not |
503 | use Moose. |
38e3283b |
504 | |
1cd45431 |
505 | You cannot override any of the methods found in Moose::Object, or the C<BUILD> |
506 | and C<DEMOLISH> methods. These will not throw an exception, but will silently |
507 | move on to the next method in the list. My reasoning for this is that you would |
508 | almost never want to do this, since it usually breaks your class. As with |
509 | overriding locally defined methods, if you do want to do this, you should do it |
510 | manually, not with Moose. |
38e3283b |
511 | |
f3c4e20e |
512 | You do not I<need> to have a reader (or accessor) for the attribute in order |
513 | to delegate to it. Moose will create a means of accessing the value for you, |
514 | however this will be several times B<less> efficient then if you had given |
515 | the attribute a reader (or accessor) to use. |
516 | |
38e3283b |
517 | Below is the documentation for each option format: |
518 | |
519 | =over 4 |
520 | |
521 | =item C<ARRAY> |
522 | |
26fbace8 |
523 | This is the most common usage for I<handles>. You basically pass a list of |
524 | method names to be delegated, and Moose will install a delegation method |
1cd45431 |
525 | for each one. |
38e3283b |
526 | |
527 | =item C<HASH> |
528 | |
26fbace8 |
529 | This is the second most common usage for I<handles>. Instead of a list of |
530 | method names, you pass a HASH ref where each key is the method name you |
531 | want installed locally, and its value is the name of the original method |
532 | in the class being delegated to. |
fd595040 |
533 | |
26fbace8 |
534 | This can be very useful for recursive classes like trees. Here is a |
fd595040 |
535 | quick example (soon to be expanded into a Moose::Cookbook::Recipe): |
38e3283b |
536 | |
1cd45431 |
537 | package Tree; |
38e3283b |
538 | use Moose; |
26fbace8 |
539 | |
38e3283b |
540 | has 'node' => (is => 'rw', isa => 'Any'); |
26fbace8 |
541 | |
38e3283b |
542 | has 'children' => ( |
543 | is => 'ro', |
544 | isa => 'ArrayRef', |
545 | default => sub { [] } |
546 | ); |
26fbace8 |
547 | |
38e3283b |
548 | has 'parent' => ( |
549 | is => 'rw', |
550 | isa => 'Tree', |
a4e516f6 |
551 | weak_ref => 1, |
38e3283b |
552 | handles => { |
553 | parent_node => 'node', |
26fbace8 |
554 | siblings => 'children', |
38e3283b |
555 | } |
556 | ); |
557 | |
1cd45431 |
558 | In this example, the Tree package gets C<parent_node> and C<siblings> methods, |
559 | which delegate to the C<node> and C<children> methods (respectively) of the Tree |
26fbace8 |
560 | instance stored in the C<parent> slot. |
38e3283b |
561 | |
562 | =item C<REGEXP> |
563 | |
26fbace8 |
564 | The regexp option works very similar to the ARRAY option, except that it builds |
565 | the list of methods for you. It starts by collecting all possible methods of the |
566 | class being delegated to, then filters that list using the regexp supplied here. |
38e3283b |
567 | |
26fbace8 |
568 | B<NOTE:> An I<isa> option is required when using the regexp option format. This |
569 | is so that we can determine (at compile time) the method list from the class. |
38e3283b |
570 | Without an I<isa> this is just not possible. |
571 | |
c84f324f |
572 | =item C<ROLE> |
573 | |
26fbace8 |
574 | With the role option, you specify the name of a role whose "interface" then |
575 | becomes the list of methods to handle. The "interface" can be defined as; the |
576 | methods of the role and any required methods of the role. It should be noted |
577 | that this does B<not> include any method modifiers or generated attribute |
c84f324f |
578 | methods (which is consistent with role composition). |
579 | |
38e3283b |
580 | =item C<CODE> |
581 | |
1cd45431 |
582 | This is the option to use when you really want to do something funky. You should |
583 | only use it if you really know what you are doing, as it involves manual |
584 | metaclass twiddling. |
38e3283b |
585 | |
1cd45431 |
586 | This takes a code reference, which should expect two arguments. The first is the |
587 | attribute meta-object this I<handles> is attached to. The second is the |
588 | metaclass of the class being delegated to. It expects you to return a hash (not |
26fbace8 |
589 | a HASH ref) of the methods you want mapped. |
38e3283b |
590 | |
591 | =back |
2c0cbef7 |
592 | |
004222dc |
593 | =item I<metaclass =E<gt> $metaclass_name> |
594 | |
595 | This tells the class to use a custom attribute metaclass for this particular |
596 | attribute. Custom attribute metaclasses are useful for extending the |
597 | capabilities of the I<has> keyword: they are the simplest way to extend the MOP, |
598 | but they are still a fairly advanced topic and too much to cover here, see |
599 | L<Moose::Cookbook::Recipe11> for more information. |
600 | |
601 | The default behavior here is to just load C<$metaclass_name>; however, we also |
602 | have a way to alias to a shorter name. This will first look to see if |
603 | B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose |
604 | will then check to see if that has the method C<register_implementation>, which |
605 | should return the actual name of the custom attribute metaclass. If there is no |
606 | C<register_implementation> method, it will fall back to using |
607 | B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name. |
608 | |
609 | =item I<traits =E<gt> [ @role_names ]> |
610 | |
611 | This tells Moose to take the list of C<@role_names> and apply them to the |
612 | attribute meta-object. This is very similar to the I<metaclass> option, but |
613 | allows you to use more than one extension at a time. This too is an advanced |
614 | topic, we don't yet have a cookbook for it though. |
615 | |
616 | As with I<metaclass>, the default behavior is to just load C<$role_name>; however, |
617 | we also have a way to alias to a shorter name. This will first look to see if |
618 | B<Moose::Meta::Attribute::Custom::Trait::$role_name> exists. If it does, Moose |
619 | will then check to see if that has the method C<register_implementation>, which |
620 | should return the actual name of the custom attribute trait. If there is no |
621 | C<register_implementation> method, it will fall back to using |
622 | B<Moose::Meta::Attribute::Custom::Trait::$metaclass_name> as the trait name. |
623 | |
6ba6d68c |
624 | =back |
625 | |
cd7eeaf5 |
626 | =item B<has +$name =E<gt> %options> |
627 | |
26fbace8 |
628 | This is variation on the normal attibute creator C<has> which allows you to |
8d62bf6d |
629 | clone and extend an attribute from a superclass or from a role. Here is an |
630 | example of the superclass usage: |
cd7eeaf5 |
631 | |
632 | package Foo; |
633 | use Moose; |
26fbace8 |
634 | |
cd7eeaf5 |
635 | has 'message' => ( |
26fbace8 |
636 | is => 'rw', |
cd7eeaf5 |
637 | isa => 'Str', |
638 | default => 'Hello, I am a Foo' |
639 | ); |
26fbace8 |
640 | |
cd7eeaf5 |
641 | package My::Foo; |
642 | use Moose; |
26fbace8 |
643 | |
cd7eeaf5 |
644 | extends 'Foo'; |
26fbace8 |
645 | |
cd7eeaf5 |
646 | has '+message' => (default => 'Hello I am My::Foo'); |
647 | |
1cd45431 |
648 | What is happening here is that B<My::Foo> is cloning the C<message> attribute |
649 | from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt> |
650 | 'Str'> characteristics, but changing the value in C<default>. |
cd7eeaf5 |
651 | |
8d62bf6d |
652 | Here is another example, but within the context of a role: |
653 | |
654 | package Foo::Role; |
655 | use Moose::Role; |
656 | |
657 | has 'message' => ( |
658 | is => 'rw', |
659 | isa => 'Str', |
660 | default => 'Hello, I am a Foo' |
661 | ); |
662 | |
663 | package My::Foo; |
664 | use Moose; |
665 | |
666 | with 'Foo::Role'; |
667 | |
668 | has '+message' => (default => 'Hello I am My::Foo'); |
669 | |
670 | In this case, we are basically taking the attribute which the role supplied |
4032c9bb |
671 | and altering it within the bounds of this feature. |
8d62bf6d |
672 | |
4032c9bb |
673 | Aside from where the attributes come from (one from superclass, the other |
674 | from a role), this feature works exactly the same. This feature is restricted |
675 | somewhat, so as to try and force at least I<some> sanity into it. You are only |
676 | allowed to change the following attributes: |
cd7eeaf5 |
677 | |
678 | =over 4 |
679 | |
26fbace8 |
680 | =item I<default> |
cd7eeaf5 |
681 | |
682 | Change the default value of an attribute. |
683 | |
26fbace8 |
684 | =item I<coerce> |
cd7eeaf5 |
685 | |
686 | Change whether the attribute attempts to coerce a value passed to it. |
687 | |
26fbace8 |
688 | =item I<required> |
cd7eeaf5 |
689 | |
690 | Change if the attribute is required to have a value. |
691 | |
692 | =item I<documentation> |
693 | |
694 | Change the documentation string associated with the attribute. |
695 | |
83cc9094 |
696 | =item I<lazy> |
697 | |
698 | Change if the attribute lazily initializes the slot. |
699 | |
cd7eeaf5 |
700 | =item I<isa> |
701 | |
aed87761 |
702 | You I<are> allowed to change the type without restriction. |
703 | |
704 | It is recommended that you use this freedom with caution. We used to |
705 | only allow for extension only if the type was a subtype of the parent's |
706 | type, but we felt that was too restrictive and is better left as a |
707 | policy descision. |
cd7eeaf5 |
708 | |
83cc9094 |
709 | =item I<handles> |
710 | |
26fbace8 |
711 | You are allowed to B<add> a new C<handles> definition, but you are B<not> |
712 | allowed to I<change> one. |
83cc9094 |
713 | |
8d62bf6d |
714 | =item I<builder> |
715 | |
716 | You are allowed to B<add> a new C<builder> definition, but you are B<not> |
717 | allowed to I<change> one. |
718 | |
cd7eeaf5 |
719 | =back |
720 | |
076c81ed |
721 | =item B<before $name|@names =E<gt> sub { ... }> |
6ba6d68c |
722 | |
076c81ed |
723 | =item B<after $name|@names =E<gt> sub { ... }> |
6ba6d68c |
724 | |
076c81ed |
725 | =item B<around $name|@names =E<gt> sub { ... }> |
6ba6d68c |
726 | |
d8af92ae |
727 | This three items are syntactic sugar for the before, after, and around method |
728 | modifier features that L<Class::MOP> provides. More information on these may be |
729 | found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method |
730 | Modifiers"> for now. |
6ba6d68c |
731 | |
159da176 |
732 | =item B<super> |
733 | |
26fbace8 |
734 | The keyword C<super> is a no-op when called outside of an C<override> method. In |
735 | the context of an C<override> method, it will call the next most appropriate |
159da176 |
736 | superclass method with the same arguments as the original method. |
737 | |
738 | =item B<override ($name, &sub)> |
739 | |
26fbace8 |
740 | An C<override> method is a way of explicitly saying "I am overriding this |
741 | method from my superclass". You can call C<super> within this method, and |
742 | it will work as expected. The same thing I<can> be accomplished with a normal |
743 | method call and the C<SUPER::> pseudo-package; it is really your choice. |
159da176 |
744 | |
745 | =item B<inner> |
746 | |
26fbace8 |
747 | The keyword C<inner>, much like C<super>, is a no-op outside of the context of |
748 | an C<augment> method. You can think of C<inner> as being the inverse of |
68efb014 |
749 | C<super>; the details of how C<inner> and C<augment> work is best described in |
004222dc |
750 | the L<Moose::Cookbook::Recipe7>. |
159da176 |
751 | |
752 | =item B<augment ($name, &sub)> |
753 | |
26fbace8 |
754 | An C<augment> method, is a way of explicitly saying "I am augmenting this |
755 | method from my superclass". Once again, the details of how C<inner> and |
004222dc |
756 | C<augment> work is best described in the L<Moose::Cookbook::Recipe7>. |
159da176 |
757 | |
6ba6d68c |
758 | =item B<confess> |
759 | |
68efb014 |
760 | This is the C<Carp::confess> function, and exported here because I use it |
004222dc |
761 | all the time. |
6ba6d68c |
762 | |
763 | =item B<blessed> |
764 | |
1cd45431 |
765 | This is the C<Scalar::Util::blessed> function, it is exported here because I |
26fbace8 |
766 | use it all the time. It is highly recommended that this is used instead of |
6ba6d68c |
767 | C<ref> anywhere you need to test for an object's class name. |
768 | |
769 | =back |
770 | |
1cd45431 |
771 | =head1 UNIMPORTING FUNCTIONS |
31f8ec72 |
772 | |
773 | =head2 B<unimport> |
774 | |
1cd45431 |
775 | Moose offers a way to remove the keywords it exports, through the C<unimport> |
31f8ec72 |
776 | method. You simply have to say C<no Moose> at the bottom of your code for this |
777 | to work. Here is an example: |
778 | |
779 | package Person; |
780 | use Moose; |
781 | |
782 | has 'first_name' => (is => 'rw', isa => 'Str'); |
783 | has 'last_name' => (is => 'rw', isa => 'Str'); |
26fbace8 |
784 | |
785 | sub full_name { |
31f8ec72 |
786 | my $self = shift; |
26fbace8 |
787 | $self->first_name . ' ' . $self->last_name |
31f8ec72 |
788 | } |
26fbace8 |
789 | |
790 | no Moose; # keywords are removed from the Person package |
31f8ec72 |
791 | |
9bcfbab1 |
792 | =head1 EXTENDING AND EMBEDDING MOOSE |
793 | |
26fbace8 |
794 | Moose also offers some options for extending or embedding it into your own |
9bcfbab1 |
795 | framework. The basic premise is to have something that sets up your class' |
26fbace8 |
796 | metaclass and export the moose declarators (C<has>, C<with>, C<extends>,...). |
9bcfbab1 |
797 | Here is an example: |
798 | |
799 | package MyFramework; |
800 | use Moose; |
26fbace8 |
801 | |
9bcfbab1 |
802 | sub import { |
803 | my $CALLER = caller(); |
804 | |
805 | strict->import; |
806 | warnings->import; |
807 | |
808 | # we should never export to main |
809 | return if $CALLER eq 'main'; |
810 | Moose::init_meta( $CALLER, 'MyFramework::Base' ); |
811 | Moose->import({into => $CALLER}); |
812 | |
813 | # Do my custom framework stuff |
26fbace8 |
814 | |
9bcfbab1 |
815 | return 1; |
816 | } |
26fbace8 |
817 | |
9bcfbab1 |
818 | =head2 B<import> |
819 | |
77a18c28 |
820 | Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}> |
9bcfbab1 |
821 | and C<{into_level =E<gt> 1}> |
822 | |
823 | =head2 B<init_meta ($class, $baseclass, $metaclass)> |
824 | |
26fbace8 |
825 | Moose does some boot strapping: it creates a metaclass object for your class, |
826 | and then injects a C<meta> accessor into your class to retrieve it. Then it |
827 | sets your baseclass to Moose::Object or the value you pass in unless you already |
828 | have one. This is all done via C<init_meta> which takes the name of your class |
2bbba362 |
829 | and optionally a baseclass and a metaclass as arguments. |
26fbace8 |
830 | |
05d9eaf6 |
831 | =head1 CAVEATS |
832 | |
833 | =over 4 |
834 | |
835 | =item * |
836 | |
1cd45431 |
837 | It should be noted that C<super> and C<inner> B<cannot> be used in the same |
838 | method. However, they may be combined within the same class hierarchy; see |
839 | F<t/014_override_augment_inner_super.t> for an example. |
05d9eaf6 |
840 | |
26fbace8 |
841 | The reason for this is that C<super> is only valid within a method |
842 | with the C<override> modifier, and C<inner> will never be valid within an |
843 | C<override> method. In fact, C<augment> will skip over any C<override> methods |
68efb014 |
844 | when searching for its appropriate C<inner>. |
05d9eaf6 |
845 | |
1cd45431 |
846 | This might seem like a restriction, but I am of the opinion that keeping these |
847 | two features separate (yet interoperable) actually makes them easy to use, since |
848 | their behavior is then easier to predict. Time will tell whether I am right or |
c84f324f |
849 | not (UPDATE: so far so good). |
05d9eaf6 |
850 | |
004222dc |
851 | =item * |
852 | |
853 | It is important to note that we currently have no simple way of combining |
854 | multiple extended versions of Moose (see L<EXTENDING AND EMBEDDING MOOSE> above), |
855 | and that in many cases they will conflict with one another. We are working on |
856 | developing a way around this issue, but in the meantime, you have been warned. |
857 | |
05d9eaf6 |
858 | =back |
859 | |
5569c072 |
860 | =head1 ACKNOWLEDGEMENTS |
861 | |
862 | =over 4 |
863 | |
54c189df |
864 | =item I blame Sam Vilain for introducing me to the insanity that is meta-models. |
5569c072 |
865 | |
54c189df |
866 | =item I blame Audrey Tang for then encouraging my meta-model habit in #perl6. |
5569c072 |
867 | |
26fbace8 |
868 | =item Without Yuval "nothingmuch" Kogman this module would not be possible, |
54c189df |
869 | and it certainly wouldn't have this name ;P |
5569c072 |
870 | |
26fbace8 |
871 | =item The basis of the TypeContraints module was Rob Kinyon's idea |
5569c072 |
872 | originally, I just ran with it. |
873 | |
638585e1 |
874 | =item Thanks to mst & chansen and the whole #moose posse for all the |
c84f324f |
875 | early ideas/feature-requests/encouragement/bug-finding. |
d46a48f3 |
876 | |
68efb014 |
877 | =item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes. |
878 | |
5569c072 |
879 | =back |
880 | |
e90c03d0 |
881 | =head1 SEE ALSO |
882 | |
883 | =over 4 |
884 | |
c84f324f |
885 | =item L<http://www.iinteractive.com/moose> |
886 | |
887 | This is the official web home of Moose, it contains links to our public SVN repo |
26fbace8 |
888 | as well as links to a number of talks and articles on Moose and Moose related |
889 | technologies. |
c84f324f |
890 | |
6ba6d68c |
891 | =item L<Class::MOP> documentation |
892 | |
893 | =item The #moose channel on irc.perl.org |
894 | |
e67a0fca |
895 | =item The Moose mailing list - moose@perl.org |
896 | |
c84f324f |
897 | =item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/5788> |
898 | |
28669f89 |
899 | =item Several Moose extension modules in the L<MooseX::> namespace. |
900 | |
c84f324f |
901 | =back |
902 | |
004222dc |
903 | =head2 Books |
904 | |
905 | =over 4 |
906 | |
907 | =item The Art of the MetaObject Protocol |
908 | |
909 | I mention this in the L<Class::MOP> docs too, this book was critical in |
910 | the development of both modules and is highly recommended. |
911 | |
912 | =back |
913 | |
26fbace8 |
914 | =head2 Papers |
c84f324f |
915 | |
916 | =over 4 |
e90c03d0 |
917 | |
159da176 |
918 | =item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf> |
919 | |
26fbace8 |
920 | This paper (suggested by lbr on #moose) was what lead to the implementation |
921 | of the C<super>/C<override> and C<inner>/C<augment> features. If you really |
1cd45431 |
922 | want to understand them, I suggest you read this. |
159da176 |
923 | |
e90c03d0 |
924 | =back |
925 | |
fcd84ca9 |
926 | =head1 BUGS |
927 | |
26fbace8 |
928 | All complex software has bugs lurking in it, and this module is no |
fcd84ca9 |
929 | exception. If you find a bug please either email me, or add the bug |
930 | to cpan-RT. |
931 | |
fcd84ca9 |
932 | =head1 AUTHOR |
933 | |
934 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
935 | |
9af1d28b |
936 | B<with contributions from:> |
db1ab48d |
937 | |
9af1d28b |
938 | Aankhen |
939 | |
940 | Adam (Alias) Kennedy |
941 | |
942 | Anders (Debolaz) Nor Berle |
943 | |
5868294f |
944 | Nathan (kolibre) Gray |
945 | |
9af1d28b |
946 | Christian (chansen) Hansen |
947 | |
e7f8d0c2 |
948 | Hans Dieter (confound) Pearcey |
949 | |
9af1d28b |
950 | Eric (ewilhelm) Wilhelm |
951 | |
952 | Guillermo (groditi) Roditi |
953 | |
954 | Jess (castaway) Robinson |
955 | |
956 | Matt (mst) Trout |
957 | |
958 | Robert (phaylon) Sedlacek |
959 | |
960 | Robert (rlb3) Boone |
961 | |
962 | Scott (konobi) McWhirter |
963 | |
f44ae52f |
964 | Shlomi (rindolf) Fish |
965 | |
9af1d28b |
966 | Yuval (nothingmuch) Kogman |
967 | |
cbe25729 |
968 | Chris (perigrin) Prather |
969 | |
e46f5cc2 |
970 | Jonathan (jrockway) Rockway |
971 | |
3ccdc84a |
972 | Piotr (dexter) Roszatycki |
973 | |
26fbace8 |
974 | Sam (mugwump) Vilain |
f1917f58 |
975 | |
ac211120 |
976 | Shawn (sartak) Moore |
977 | |
9af1d28b |
978 | ... and many other #moose folks |
98aae381 |
979 | |
fcd84ca9 |
980 | =head1 COPYRIGHT AND LICENSE |
981 | |
778db3ac |
982 | Copyright 2006-2008 by Infinity Interactive, Inc. |
fcd84ca9 |
983 | |
984 | L<http://www.iinteractive.com> |
985 | |
986 | This library is free software; you can redistribute it and/or modify |
26fbace8 |
987 | it under the same terms as Perl itself. |
fcd84ca9 |
988 | |
ddd0ec20 |
989 | =cut |