Commit | Line | Data |
c0e30cf5 |
1 | |
2 | package Moose::Meta::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
78cd1d3b |
7 | use Scalar::Util 'blessed', 'weaken', 'reftype'; |
a15dff8d |
8 | use Carp 'confess'; |
9 | |
4fd69d6c |
10 | our $VERSION = '0.08'; |
78cd1d3b |
11 | |
a3c7e2fe |
12 | use Moose::Util::TypeConstraints (); |
bc1e29b5 |
13 | |
c0e30cf5 |
14 | use base 'Class::MOP::Attribute'; |
15 | |
452bac1b |
16 | # options which are not directly used |
17 | # but we store them for metadata purposes |
98aae381 |
18 | __PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata')); |
19 | __PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata')); |
20 | __PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata')); |
452bac1b |
21 | |
22 | # these are actual options for the attrs |
1a563243 |
23 | __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); |
24 | __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); |
25 | __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' )); |
26 | __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); |
27 | __PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref')); |
82168dbb |
28 | __PACKAGE__->meta->add_attribute('type_constraint' => ( |
29 | reader => 'type_constraint', |
30 | predicate => 'has_type_constraint', |
31 | )); |
8c9d74e7 |
32 | __PACKAGE__->meta->add_attribute('trigger' => ( |
33 | reader => 'trigger', |
34 | predicate => 'has_trigger', |
35 | )); |
452bac1b |
36 | __PACKAGE__->meta->add_attribute('handles' => ( |
37 | reader => 'handles', |
38 | predicate => 'has_handles', |
39 | )); |
82168dbb |
40 | |
78cd1d3b |
41 | sub new { |
42 | my ($class, $name, %options) = @_; |
1d768fb1 |
43 | $class->_process_options($name, \%options); |
98aae381 |
44 | return $class->SUPER::new($name, %options); |
1d768fb1 |
45 | } |
46 | |
ce0e8d63 |
47 | sub clone_and_inherit_options { |
48 | my ($self, %options) = @_; |
49 | # you can change default, required and coerce |
50 | my %actual_options; |
51 | foreach my $legal_option (qw(default coerce required)) { |
52 | if (exists $options{$legal_option}) { |
53 | $actual_options{$legal_option} = $options{$legal_option}; |
54 | delete $options{$legal_option}; |
55 | } |
56 | } |
fcb7afc2 |
57 | # isa can be changed, but only if the |
58 | # new type is a subtype |
ce0e8d63 |
59 | if ($options{isa}) { |
60 | my $type_constraint; |
61 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
62 | $type_constraint = $options{isa}; |
63 | } |
64 | else { |
65 | $type_constraint = Moose::Util::TypeConstraints::find_type_constraint($options{isa}); |
66 | (defined $type_constraint) |
67 | || confess "Could not find the type constraint '" . $options{isa} . "'"; |
68 | } |
2a0f3bd3 |
69 | # NOTE: |
70 | # check here to see if the new type |
71 | # is a subtype of the old one |
ce0e8d63 |
72 | ($type_constraint->is_subtype_of($self->type_constraint->name)) |
73 | || confess "New type constraint setting must be a subtype of inherited one" |
2a0f3bd3 |
74 | # iff we have a type constraint that is ... |
ce0e8d63 |
75 | if $self->has_type_constraint; |
2a0f3bd3 |
76 | # then we use it :) |
ce0e8d63 |
77 | $actual_options{type_constraint} = $type_constraint; |
78 | delete $options{isa}; |
79 | } |
80 | (scalar keys %options == 0) |
81 | || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")"; |
82 | $self->clone(%actual_options); |
1d768fb1 |
83 | } |
84 | |
85 | sub _process_options { |
86 | my ($class, $name, $options) = @_; |
452bac1b |
87 | |
1d768fb1 |
88 | if (exists $options->{is}) { |
89 | if ($options->{is} eq 'ro') { |
90 | $options->{reader} = $name; |
91 | (!exists $options->{trigger}) |
8c9d74e7 |
92 | || confess "Cannot have a trigger on a read-only attribute"; |
78cd1d3b |
93 | } |
1d768fb1 |
94 | elsif ($options->{is} eq 'rw') { |
452bac1b |
95 | $options->{accessor} = $name; |
98aae381 |
96 | ((reftype($options->{trigger}) || '') eq 'CODE') |
97 | || confess "Trigger must be a CODE ref" |
98 | if exists $options->{trigger}; |
452bac1b |
99 | } |
100 | else { |
101 | confess "I do not understand this option (is => " . $options->{is} . ")" |
78cd1d3b |
102 | } |
103 | } |
104 | |
1d768fb1 |
105 | if (exists $options->{isa}) { |
02a0fb52 |
106 | |
1d768fb1 |
107 | if (exists $options->{does}) { |
108 | if (eval { $options->{isa}->can('does') }) { |
109 | ($options->{isa}->does($options->{does})) |
02a0fb52 |
110 | || confess "Cannot have an isa option and a does option if the isa does not do the does"; |
111 | } |
7eaef7ad |
112 | else { |
113 | confess "Cannot have an isa option which cannot ->does()"; |
114 | } |
02a0fb52 |
115 | } |
116 | |
78cd1d3b |
117 | # allow for anon-subtypes here ... |
1d768fb1 |
118 | if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) { |
119 | $options->{type_constraint} = $options->{isa}; |
78cd1d3b |
120 | } |
121 | else { |
c07af9d2 |
122 | |
1d768fb1 |
123 | if ($options->{isa} =~ /\|/) { |
124 | my @type_constraints = split /\s*\|\s*/ => $options->{isa}; |
125 | $options->{type_constraint} = Moose::Util::TypeConstraints::create_type_constraint_union( |
c07af9d2 |
126 | @type_constraints |
78cd1d3b |
127 | ); |
c07af9d2 |
128 | } |
129 | else { |
130 | # otherwise assume it is a constraint |
1d768fb1 |
131 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{isa}); |
c07af9d2 |
132 | # if the constraing it not found .... |
133 | unless (defined $constraint) { |
134 | # assume it is a foreign class, and make |
135 | # an anon constraint for it |
136 | $constraint = Moose::Util::TypeConstraints::subtype( |
137 | 'Object', |
1d768fb1 |
138 | Moose::Util::TypeConstraints::where { $_->isa($options->{isa}) } |
c07af9d2 |
139 | ); |
140 | } |
1d768fb1 |
141 | $options->{type_constraint} = $constraint; |
c07af9d2 |
142 | } |
78cd1d3b |
143 | } |
144 | } |
1d768fb1 |
145 | elsif (exists $options->{does}) { |
02a0fb52 |
146 | # allow for anon-subtypes here ... |
1d768fb1 |
147 | if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) { |
148 | $options->{type_constraint} = $options->{isa}; |
02a0fb52 |
149 | } |
150 | else { |
151 | # otherwise assume it is a constraint |
1d768fb1 |
152 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options->{does}); |
02a0fb52 |
153 | # if the constraing it not found .... |
154 | unless (defined $constraint) { |
155 | # assume it is a foreign class, and make |
156 | # an anon constraint for it |
157 | $constraint = Moose::Util::TypeConstraints::subtype( |
158 | 'Role', |
1d768fb1 |
159 | Moose::Util::TypeConstraints::where { $_->does($options->{does}) } |
02a0fb52 |
160 | ); |
161 | } |
1d768fb1 |
162 | $options->{type_constraint} = $constraint; |
02a0fb52 |
163 | } |
164 | } |
78cd1d3b |
165 | |
1d768fb1 |
166 | if (exists $options->{coerce} && $options->{coerce}) { |
167 | (exists $options->{type_constraint}) |
3ec7b7a3 |
168 | || confess "You cannot have coercion without specifying a type constraint"; |
4b598ea3 |
169 | confess "You cannot have a weak reference to a coerced value" |
1d768fb1 |
170 | if $options->{weak_ref}; |
ca01a97b |
171 | } |
78cd1d3b |
172 | |
536f0b17 |
173 | if (exists $options->{auto_deref} && $options->{auto_deref}) { |
174 | (exists $options->{type_constraint}) |
175 | || confess "You cannot auto-dereference without specifying a type constraint"; |
94b8bbb8 |
176 | ($options->{type_constraint}->is_a_type_of('ArrayRef') || |
177 | $options->{type_constraint}->is_a_type_of('HashRef')) |
536f0b17 |
178 | || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef"; |
179 | } |
180 | |
1d768fb1 |
181 | if (exists $options->{lazy} && $options->{lazy}) { |
182 | (exists $options->{default}) |
ca01a97b |
183 | || confess "You cannot have lazy attribute without specifying a default value for it"; |
1d768fb1 |
184 | } |
78cd1d3b |
185 | } |
c0e30cf5 |
186 | |
d500266f |
187 | sub initialize_instance_slot { |
ddd0ec20 |
188 | my ($self, $meta_instance, $instance, $params) = @_; |
d500266f |
189 | my $init_arg = $self->init_arg(); |
190 | # try to fetch the init arg from the %params ... |
ddd0ec20 |
191 | |
d500266f |
192 | my $val; |
193 | if (exists $params->{$init_arg}) { |
194 | $val = $params->{$init_arg}; |
195 | } |
196 | else { |
197 | # skip it if it's lazy |
198 | return if $self->is_lazy; |
199 | # and die if it's required and doesn't have a default value |
200 | confess "Attribute (" . $self->name . ") is required" |
201 | if $self->is_required && !$self->has_default; |
202 | } |
ddd0ec20 |
203 | |
d500266f |
204 | # if nothing was in the %params, we can use the |
205 | # attribute's default value (if it has one) |
206 | if (!defined $val && $self->has_default) { |
207 | $val = $self->default($instance); |
208 | } |
209 | if (defined $val) { |
210 | if ($self->has_type_constraint) { |
c07af9d2 |
211 | my $type_constraint = $self->type_constraint; |
212 | if ($self->should_coerce && $type_constraint->has_coercion) { |
0a5bd159 |
213 | $val = $type_constraint->coerce($val); |
d500266f |
214 | } |
c07af9d2 |
215 | (defined($type_constraint->check($val))) |
216 | || confess "Attribute (" . |
217 | $self->name . |
8449e6e7 |
218 | ") does not pass the type constraint (" . |
c07af9d2 |
219 | $type_constraint->name . |
220 | ") with '$val'"; |
d500266f |
221 | } |
222 | } |
ddd0ec20 |
223 | |
ac1ef2f9 |
224 | $meta_instance->set_slot_value($instance, $self->name, $val); |
225 | $meta_instance->weaken_slot_value($instance, $self->name) |
226 | if ref $val && $self->is_weak_ref; |
d500266f |
227 | } |
228 | |
9e93dd19 |
229 | ## Accessor inline subroutines |
230 | |
67ad26d9 |
231 | sub _inline_check_constraint { |
ac1ef2f9 |
232 | my ($self, $value) = @_; |
67ad26d9 |
233 | return '' unless $self->has_type_constraint; |
234 | |
235 | # FIXME - remove 'unless defined($value) - constraint Undef |
236 | return sprintf <<'EOF', $value, $value, $value, $value |
43123819 |
237 | defined($type_constraint->(%s)) |
8449e6e7 |
238 | || confess "Attribute (" . $attr->name . ") does not pass the type constraint (" |
67ad26d9 |
239 | . $attr->type_constraint->name . ") with " . (defined(%s) ? "'%s'" : "undef") |
240 | if defined(%s); |
241 | EOF |
242 | } |
243 | |
9e93dd19 |
244 | sub _inline_check_coercion { |
245 | my $self = shift; |
246 | return '' unless $self->should_coerce; |
0a5bd159 |
247 | return 'my $val = $attr->type_constraint->coerce($_[1]);' |
9e93dd19 |
248 | } |
249 | |
250 | sub _inline_check_required { |
251 | my $self = shift; |
252 | return '' unless $self->is_required; |
253 | return 'defined($_[1]) || confess "Attribute ($attr_name) is required, so cannot be set to undef";' |
254 | } |
255 | |
256 | sub _inline_check_lazy { |
257 | my $self = shift; |
258 | return '' unless $self->is_lazy; |
4fd69d6c |
259 | if ($self->has_type_constraint) { |
260 | # NOTE: |
261 | # this could probably be cleaned |
262 | # up and streamlined a little more |
263 | return 'unless (exists $_[0]->{$attr_name}) {' . |
264 | ' if ($attr->has_default) {' . |
265 | ' my $default = $attr->default($_[0]);' . |
43123819 |
266 | ' (defined($type_constraint->($default)))' . |
4fd69d6c |
267 | ' || confess "Attribute (" . $attr->name . ") does not pass the type constraint ("' . |
268 | ' . $attr->type_constraint->name . ") with " . (defined($default) ? "\'$default\'" : "undef")' . |
269 | ' if defined($default);' . |
270 | ' $_[0]->{$attr_name} = $default; ' . |
271 | ' }' . |
272 | ' else {' . |
273 | ' $_[0]->{$attr_name} = undef;' . |
274 | ' }' . |
275 | '}'; |
276 | } |
9e93dd19 |
277 | return '$_[0]->{$attr_name} = ($attr->has_default ? $attr->default($_[0]) : undef)' |
278 | . 'unless exists $_[0]->{$attr_name};'; |
279 | } |
280 | |
281 | |
67ad26d9 |
282 | sub _inline_store { |
ac1ef2f9 |
283 | my ($self, $instance, $value) = @_; |
67ad26d9 |
284 | |
285 | my $mi = $self->associated_class->get_meta_instance; |
ac1ef2f9 |
286 | my $slot_name = sprintf "'%s'", $self->slots; |
67ad26d9 |
287 | |
ac1ef2f9 |
288 | my $code = $mi->inline_set_slot_value($instance, $slot_name, $value) . ";"; |
289 | $code .= $mi->inline_weaken_slot_value($instance, $slot_name, $value) . ";" |
290 | if $self->is_weak_ref; |
291 | return $code; |
8a7a9c53 |
292 | } |
293 | |
67ad26d9 |
294 | sub _inline_trigger { |
ac1ef2f9 |
295 | my ($self, $instance, $value) = @_; |
67ad26d9 |
296 | return '' unless $self->has_trigger; |
297 | return sprintf('$attr->trigger->(%s, %s, $attr);', $instance, $value); |
8a7a9c53 |
298 | } |
299 | |
ddd0ec20 |
300 | sub _inline_get { |
ac1ef2f9 |
301 | my ($self, $instance) = @_; |
ddd0ec20 |
302 | |
303 | my $mi = $self->associated_class->get_meta_instance; |
ac1ef2f9 |
304 | my $slot_name = sprintf "'%s'", $self->slots; |
ddd0ec20 |
305 | |
ac1ef2f9 |
306 | return $mi->inline_get_slot_value($instance, $slot_name); |
ddd0ec20 |
307 | } |
308 | |
1a563243 |
309 | sub _inline_auto_deref { |
310 | my ( $self, $ref_value ) = @_; |
311 | |
312 | return $ref_value unless $self->should_auto_deref; |
313 | |
94b8bbb8 |
314 | my $type_constraint = $self->type_constraint; |
1a563243 |
315 | |
536f0b17 |
316 | my $sigil; |
94b8bbb8 |
317 | if ($type_constraint->is_a_type_of('ArrayRef')) { |
1a563243 |
318 | $sigil = '@'; |
536f0b17 |
319 | } |
94b8bbb8 |
320 | elsif ($type_constraint->is_a_type_of('HashRef')) { |
1a563243 |
321 | $sigil = '%'; |
536f0b17 |
322 | } |
323 | else { |
94b8bbb8 |
324 | confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'"; |
1a563243 |
325 | } |
326 | |
327 | "(wantarray() ? $sigil\{ ( $ref_value ) || return } : ( $ref_value ) )"; |
328 | } |
329 | |
a15dff8d |
330 | sub generate_accessor_method { |
67ad26d9 |
331 | my ($attr, $attr_name) = @_; |
332 | my $value_name = $attr->should_coerce ? '$val' : '$_[1]'; |
333 | my $mi = $attr->associated_class->get_meta_instance; |
ac1ef2f9 |
334 | my $slot_name = sprintf "'%s'", $attr->slots; |
67ad26d9 |
335 | my $inv = '$_[0]'; |
ca01a97b |
336 | my $code = 'sub { ' |
337 | . 'if (scalar(@_) == 2) {' |
9e93dd19 |
338 | . $attr->_inline_check_required |
339 | . $attr->_inline_check_coercion |
ac1ef2f9 |
340 | . $attr->_inline_check_constraint($value_name) |
341 | . $attr->_inline_store($inv, $value_name) |
342 | . $attr->_inline_trigger($inv, $value_name) |
ca01a97b |
343 | . ' }' |
9e93dd19 |
344 | . $attr->_inline_check_lazy |
536f0b17 |
345 | . 'return ' . $attr->_inline_auto_deref($attr->_inline_get($inv)) |
ca01a97b |
346 | . ' }'; |
43123819 |
347 | |
348 | # NOTE: |
349 | # set up the environment |
350 | my $type_constraint = $attr->type_constraint |
351 | ? $attr->type_constraint->_compiled_type_constraint |
352 | : undef; |
353 | |
ca01a97b |
354 | my $sub = eval $code; |
67ad26d9 |
355 | confess "Could not create accessor for '$attr_name' because $@ \n code: $code" if $@; |
ca01a97b |
356 | return $sub; |
a15dff8d |
357 | } |
358 | |
359 | sub generate_writer_method { |
67ad26d9 |
360 | my ($attr, $attr_name) = @_; |
361 | my $value_name = $attr->should_coerce ? '$val' : '$_[1]'; |
362 | my $inv = '$_[0]'; |
ca01a97b |
363 | my $code = 'sub { ' |
9e93dd19 |
364 | . $attr->_inline_check_required |
365 | . $attr->_inline_check_coercion |
ac1ef2f9 |
366 | . $attr->_inline_check_constraint($value_name) |
367 | . $attr->_inline_store($inv, $value_name) |
368 | . $attr->_inline_trigger($inv, $value_name) |
ca01a97b |
369 | . ' }'; |
43123819 |
370 | |
371 | # NOTE: |
372 | # set up the environment |
373 | my $type_constraint = $attr->type_constraint |
374 | ? $attr->type_constraint->_compiled_type_constraint |
375 | : undef; |
376 | |
ca01a97b |
377 | my $sub = eval $code; |
378 | confess "Could not create writer for '$attr_name' because $@ \n code: $code" if $@; |
379 | return $sub; |
a15dff8d |
380 | } |
c0e30cf5 |
381 | |
d7f17ebb |
382 | sub generate_reader_method { |
9e93dd19 |
383 | my $attr = shift; |
384 | my $attr_name = $attr->slots; |
ca01a97b |
385 | my $code = 'sub {' |
386 | . 'confess "Cannot assign a value to a read-only accessor" if @_ > 1;' |
9e93dd19 |
387 | . $attr->_inline_check_lazy |
388 | . 'return ' . $attr->_inline_auto_deref( '$_[0]->{$attr_name}' ) . ';' |
ca01a97b |
389 | . '}'; |
390 | my $sub = eval $code; |
391 | confess "Could not create reader for '$attr_name' because $@ \n code: $code" if $@; |
392 | return $sub; |
d7f17ebb |
393 | } |
394 | |
452bac1b |
395 | sub install_accessors { |
396 | my $self = shift; |
397 | $self->SUPER::install_accessors(@_); |
398 | |
399 | if ($self->has_handles) { |
400 | |
401 | # NOTE: |
402 | # Here we canonicalize the 'handles' option |
403 | # this will sort out any details and always |
404 | # return an hash of methods which we want |
405 | # to delagate to, see that method for details |
406 | my %handles = $self->_canonicalize_handles(); |
407 | |
408 | # find the name of the accessor for this attribute |
409 | my $accessor_name = $self->reader || $self->accessor; |
410 | (defined $accessor_name) |
411 | || confess "You cannot install delegation without a reader or accessor for the attribute"; |
412 | |
413 | # make sure we handle HASH accessors correctly |
414 | ($accessor_name) = keys %{$accessor_name} |
415 | if ref($accessor_name) eq 'HASH'; |
416 | |
417 | # install the delegation ... |
418 | my $associated_class = $self->associated_class; |
419 | foreach my $handle (keys %handles) { |
420 | my $method_to_call = $handles{$handle}; |
421 | |
422 | (!$associated_class->has_method($handle)) |
423 | || confess "You cannot overwrite a locally defined method ($handle) with a delegation"; |
424 | |
425 | if ((reftype($method_to_call) || '') eq 'CODE') { |
426 | $associated_class->add_method($handle => $method_to_call); |
427 | } |
428 | else { |
429 | $associated_class->add_method($handle => sub { |
b805c70c |
430 | # FIXME |
431 | # we should check for lack of |
432 | # a callable return value from |
433 | # the accessor here |
452bac1b |
434 | ((shift)->$accessor_name())->$method_to_call(@_); |
435 | }); |
436 | } |
437 | } |
438 | } |
439 | |
440 | return; |
441 | } |
442 | |
98aae381 |
443 | # private methods to help delegation ... |
444 | |
452bac1b |
445 | sub _canonicalize_handles { |
446 | my $self = shift; |
447 | my $handles = $self->handles; |
448 | if (ref($handles) eq 'HASH') { |
449 | return %{$handles}; |
450 | } |
451 | elsif (ref($handles) eq 'ARRAY') { |
452 | return map { $_ => $_ } @{$handles}; |
453 | } |
454 | elsif (ref($handles) eq 'Regexp') { |
455 | ($self->has_type_constraint) |
456 | || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)"; |
457 | return map { ($_ => $_) } |
458 | grep { $handles } $self->_get_delegate_method_list; |
459 | } |
460 | elsif (ref($handles) eq 'CODE') { |
461 | return $handles->($self, $self->_find_delegate_metaclass); |
462 | } |
463 | else { |
464 | confess "Unable to canonicalize the 'handles' option with $handles"; |
465 | } |
466 | } |
467 | |
468 | sub _find_delegate_metaclass { |
469 | my $self = shift; |
98aae381 |
470 | if (my $class = $self->_isa_metadata) { |
452bac1b |
471 | # if the class does have |
472 | # a meta method, use it |
473 | return $class->meta if $class->can('meta'); |
474 | # otherwise we might be |
475 | # dealing with a non-Moose |
476 | # class, and need to make |
477 | # our own metaclass |
478 | return Moose::Meta::Class->initialize($class); |
479 | } |
98aae381 |
480 | elsif (my $role = $self->_does_metadata) { |
452bac1b |
481 | # our role will always have |
482 | # a meta method |
98aae381 |
483 | return $role->meta; |
452bac1b |
484 | } |
485 | else { |
486 | confess "Cannot find delegate metaclass for attribute " . $self->name; |
487 | } |
488 | } |
489 | |
490 | sub _get_delegate_method_list { |
491 | my $self = shift; |
492 | my $meta = $self->_find_delegate_metaclass; |
493 | if ($meta->isa('Class::MOP::Class')) { |
093b12c2 |
494 | return map { $_->{name} } # NOTE: !never! delegate &meta |
495 | grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' } |
452bac1b |
496 | $meta->compute_all_applicable_methods; |
497 | } |
498 | elsif ($meta->isa('Moose::Meta::Role')) { |
499 | return $meta->get_method_list; |
500 | } |
501 | else { |
502 | confess "Unable to recognize the delegate metaclass '$meta'"; |
503 | } |
504 | } |
505 | |
c0e30cf5 |
506 | 1; |
507 | |
508 | __END__ |
509 | |
510 | =pod |
511 | |
512 | =head1 NAME |
513 | |
6ba6d68c |
514 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
515 | |
516 | =head1 DESCRIPTION |
517 | |
e522431d |
518 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
6ba6d68c |
519 | extensions. |
520 | |
521 | For the most part, the only time you will ever encounter an |
522 | instance of this class is if you are doing some serious deep |
523 | introspection. To really understand this class, you need to refer |
524 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
525 | |
c0e30cf5 |
526 | =head1 METHODS |
527 | |
6ba6d68c |
528 | =head2 Overridden methods |
529 | |
530 | These methods override methods in L<Class::MOP::Attribute> and add |
531 | Moose specific features. You can safely assume though that they |
532 | will behave just as L<Class::MOP::Attribute> does. |
533 | |
c0e30cf5 |
534 | =over 4 |
535 | |
536 | =item B<new> |
537 | |
d500266f |
538 | =item B<initialize_instance_slot> |
539 | |
a15dff8d |
540 | =item B<generate_accessor_method> |
541 | |
542 | =item B<generate_writer_method> |
543 | |
d7f17ebb |
544 | =item B<generate_reader_method> |
545 | |
452bac1b |
546 | =item B<install_accessors> |
547 | |
a15dff8d |
548 | =back |
549 | |
6ba6d68c |
550 | =head2 Additional Moose features |
551 | |
8449e6e7 |
552 | Moose attributes support type-constraint checking, weak reference |
6ba6d68c |
553 | creation and type coercion. |
554 | |
a15dff8d |
555 | =over 4 |
556 | |
9e93dd19 |
557 | =item B<clone_and_inherit_options> |
558 | |
559 | This is to support the C<has '+foo'> feature, it clones an attribute |
560 | from a superclass and allows a very specific set of changes to be made |
561 | to the attribute. |
562 | |
a15dff8d |
563 | =item B<has_type_constraint> |
564 | |
6ba6d68c |
565 | Returns true if this meta-attribute has a type constraint. |
566 | |
a15dff8d |
567 | =item B<type_constraint> |
568 | |
6ba6d68c |
569 | A read-only accessor for this meta-attribute's type constraint. For |
570 | more information on what you can do with this, see the documentation |
571 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
572 | |
452bac1b |
573 | =item B<has_handles> |
574 | |
575 | Returns true if this meta-attribute performs delegation. |
576 | |
577 | =item B<handles> |
578 | |
579 | This returns the value which was passed into the handles option. |
580 | |
6ba6d68c |
581 | =item B<is_weak_ref> |
a15dff8d |
582 | |
02a0fb52 |
583 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
584 | |
ca01a97b |
585 | =item B<is_required> |
586 | |
02a0fb52 |
587 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
588 | |
589 | =item B<is_lazy> |
590 | |
02a0fb52 |
591 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
592 | |
593 | NOTE: lazy attributes, B<must> have a C<default> field set. |
594 | |
34a66aa3 |
595 | =item B<should_coerce> |
4b598ea3 |
596 | |
02a0fb52 |
597 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
598 | |
536f0b17 |
599 | =item B<should_auto_deref> |
600 | |
601 | Returns true if this meta-attribute should perform automatic |
602 | auto-dereferencing. |
603 | |
604 | NOTE: This can only be done for attributes whose type constraint is |
605 | either I<ArrayRef> or I<HashRef>. |
606 | |
8c9d74e7 |
607 | =item B<has_trigger> |
608 | |
02a0fb52 |
609 | Returns true if this meta-attribute has a trigger set. |
610 | |
8c9d74e7 |
611 | =item B<trigger> |
612 | |
02a0fb52 |
613 | This is a CODE reference which will be executed every time the |
614 | value of an attribute is assigned. The CODE ref will get two values, |
615 | the invocant and the new value. This can be used to handle I<basic> |
616 | bi-directional relations. |
617 | |
c0e30cf5 |
618 | =back |
619 | |
620 | =head1 BUGS |
621 | |
622 | All complex software has bugs lurking in it, and this module is no |
623 | exception. If you find a bug please either email me, or add the bug |
624 | to cpan-RT. |
625 | |
c0e30cf5 |
626 | =head1 AUTHOR |
627 | |
628 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
629 | |
98aae381 |
630 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
631 | |
c0e30cf5 |
632 | =head1 COPYRIGHT AND LICENSE |
633 | |
634 | Copyright 2006 by Infinity Interactive, Inc. |
635 | |
636 | L<http://www.iinteractive.com> |
637 | |
638 | This library is free software; you can redistribute it and/or modify |
639 | it under the same terms as Perl itself. |
640 | |
8a7a9c53 |
641 | =cut |