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 | |
4c4fbe56 |
10 | our $VERSION = '0.05'; |
78cd1d3b |
11 | |
a3c7e2fe |
12 | use Moose::Util::TypeConstraints (); |
bc1e29b5 |
13 | |
c0e30cf5 |
14 | use base 'Class::MOP::Attribute'; |
15 | |
ca01a97b |
16 | __PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' )); |
17 | __PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' )); |
6ba6d68c |
18 | __PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce')); |
19 | __PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' )); |
82168dbb |
20 | __PACKAGE__->meta->add_attribute('type_constraint' => ( |
21 | reader => 'type_constraint', |
22 | predicate => 'has_type_constraint', |
23 | )); |
8c9d74e7 |
24 | __PACKAGE__->meta->add_attribute('trigger' => ( |
25 | reader => 'trigger', |
26 | predicate => 'has_trigger', |
27 | )); |
82168dbb |
28 | |
78cd1d3b |
29 | sub new { |
30 | my ($class, $name, %options) = @_; |
31 | |
32 | if (exists $options{is}) { |
33 | if ($options{is} eq 'ro') { |
34 | $options{reader} = $name; |
8c9d74e7 |
35 | (!exists $options{trigger}) |
36 | || confess "Cannot have a trigger on a read-only attribute"; |
78cd1d3b |
37 | } |
38 | elsif ($options{is} eq 'rw') { |
39 | $options{accessor} = $name; |
7eaef7ad |
40 | ((reftype($options{trigger}) || '') eq 'CODE') |
8c9d74e7 |
41 | || confess "A trigger must be a CODE reference" |
42 | if exists $options{trigger}; |
78cd1d3b |
43 | } |
44 | } |
45 | |
46 | if (exists $options{isa}) { |
02a0fb52 |
47 | |
48 | if (exists $options{does}) { |
49 | if (eval { $options{isa}->can('does') }) { |
50 | ($options{isa}->does($options{does})) |
51 | || confess "Cannot have an isa option and a does option if the isa does not do the does"; |
52 | } |
7eaef7ad |
53 | else { |
54 | confess "Cannot have an isa option which cannot ->does()"; |
55 | } |
02a0fb52 |
56 | } |
57 | |
78cd1d3b |
58 | # allow for anon-subtypes here ... |
59 | if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) { |
60 | $options{type_constraint} = $options{isa}; |
61 | } |
62 | else { |
c07af9d2 |
63 | |
64 | if ($options{isa} =~ /\|/) { |
65 | my @type_constraints = split /\s*\|\s*/ => $options{isa}; |
66 | $options{type_constraint} = Moose::Util::TypeConstraints::create_type_constraint_union( |
67 | @type_constraints |
78cd1d3b |
68 | ); |
c07af9d2 |
69 | } |
70 | else { |
71 | # otherwise assume it is a constraint |
72 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options{isa}); |
73 | # if the constraing it not found .... |
74 | unless (defined $constraint) { |
75 | # assume it is a foreign class, and make |
76 | # an anon constraint for it |
77 | $constraint = Moose::Util::TypeConstraints::subtype( |
78 | 'Object', |
79 | Moose::Util::TypeConstraints::where { $_->isa($options{isa}) } |
80 | ); |
81 | } |
82 | $options{type_constraint} = $constraint; |
83 | } |
78cd1d3b |
84 | } |
85 | } |
02a0fb52 |
86 | elsif (exists $options{does}) { |
87 | # allow for anon-subtypes here ... |
88 | if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) { |
89 | $options{type_constraint} = $options{isa}; |
90 | } |
91 | else { |
92 | # otherwise assume it is a constraint |
93 | my $constraint = Moose::Util::TypeConstraints::find_type_constraint($options{does}); |
94 | # if the constraing it not found .... |
95 | unless (defined $constraint) { |
96 | # assume it is a foreign class, and make |
97 | # an anon constraint for it |
98 | $constraint = Moose::Util::TypeConstraints::subtype( |
99 | 'Role', |
100 | Moose::Util::TypeConstraints::where { $_->does($options{does}) } |
101 | ); |
102 | } |
103 | $options{type_constraint} = $constraint; |
104 | } |
105 | } |
78cd1d3b |
106 | |
4b598ea3 |
107 | if (exists $options{coerce} && $options{coerce}) { |
108 | (exists $options{type_constraint}) |
109 | || confess "You cannot have coercion without specifying a type constraint"; |
c07af9d2 |
110 | (!$options{type_constraint}->isa('Moose::Meta::TypeConstraint::Union')) |
111 | || confess "You cannot have coercion with a type constraint union"; |
4b598ea3 |
112 | confess "You cannot have a weak reference to a coerced value" |
113 | if $options{weak_ref}; |
ca01a97b |
114 | } |
78cd1d3b |
115 | |
ca01a97b |
116 | if (exists $options{lazy} && $options{lazy}) { |
117 | (exists $options{default}) |
118 | || confess "You cannot have lazy attribute without specifying a default value for it"; |
78cd1d3b |
119 | } |
120 | |
121 | $class->SUPER::new($name, %options); |
122 | } |
c0e30cf5 |
123 | |
d500266f |
124 | sub initialize_instance_slot { |
125 | my ($self, $class, $instance, $params) = @_; |
126 | my $init_arg = $self->init_arg(); |
127 | # try to fetch the init arg from the %params ... |
128 | my $val; |
129 | if (exists $params->{$init_arg}) { |
130 | $val = $params->{$init_arg}; |
131 | } |
132 | else { |
133 | # skip it if it's lazy |
134 | return if $self->is_lazy; |
135 | # and die if it's required and doesn't have a default value |
136 | confess "Attribute (" . $self->name . ") is required" |
137 | if $self->is_required && !$self->has_default; |
138 | } |
139 | # if nothing was in the %params, we can use the |
140 | # attribute's default value (if it has one) |
141 | if (!defined $val && $self->has_default) { |
142 | $val = $self->default($instance); |
143 | } |
144 | if (defined $val) { |
145 | if ($self->has_type_constraint) { |
c07af9d2 |
146 | my $type_constraint = $self->type_constraint; |
147 | if ($self->should_coerce && $type_constraint->has_coercion) { |
148 | $val = $type_constraint->coercion->coerce($val); |
d500266f |
149 | } |
c07af9d2 |
150 | (defined($type_constraint->check($val))) |
151 | || confess "Attribute (" . |
152 | $self->name . |
153 | ") does not pass the type contraint (" . |
154 | $type_constraint->name . |
155 | ") with '$val'"; |
d500266f |
156 | } |
157 | } |
158 | $instance->{$self->name} = $val; |
159 | if (defined $val && $self->is_weak_ref) { |
160 | weaken($instance->{$self->name}); |
161 | } |
162 | } |
163 | |
a15dff8d |
164 | sub generate_accessor_method { |
165 | my ($self, $attr_name) = @_; |
ca01a97b |
166 | my $value_name = $self->should_coerce ? '$val' : '$_[1]'; |
167 | my $code = 'sub { ' |
168 | . 'if (scalar(@_) == 2) {' |
169 | . ($self->is_required ? |
170 | 'defined($_[1]) || confess "Attribute ($attr_name) is required, so cannot be set to undef";' |
171 | : '') |
172 | . ($self->should_coerce ? |
173 | 'my $val = $self->type_constraint->coercion->coerce($_[1]);' |
174 | : '') |
175 | . ($self->has_type_constraint ? |
176 | ('(defined $self->type_constraint->check(' . $value_name . '))' |
c07af9d2 |
177 | . '|| confess "Attribute ($attr_name) does not pass the type contraint (" . $self->type_constraint->name . ") with \'' . $value_name . '\'"' |
ca01a97b |
178 | . 'if defined ' . $value_name . ';') |
179 | : '') |
180 | . '$_[0]->{$attr_name} = ' . $value_name . ';' |
181 | . ($self->is_weak_ref ? |
182 | 'weaken($_[0]->{$attr_name});' |
183 | : '') |
8c9d74e7 |
184 | . ($self->has_trigger ? |
185 | '$self->trigger->($_[0], ' . $value_name . ');' |
186 | : '') |
ca01a97b |
187 | . ' }' |
188 | . ($self->is_lazy ? |
189 | '$_[0]->{$attr_name} = ($self->has_default ? $self->default($_[0]) : undef)' |
190 | . 'unless exists $_[0]->{$attr_name};' |
191 | : '') |
192 | . ' $_[0]->{$attr_name};' |
193 | . ' }'; |
194 | my $sub = eval $code; |
195 | confess "Could not create writer for '$attr_name' because $@ \n code: $code" if $@; |
196 | return $sub; |
a15dff8d |
197 | } |
198 | |
199 | sub generate_writer_method { |
200 | my ($self, $attr_name) = @_; |
ca01a97b |
201 | my $value_name = $self->should_coerce ? '$val' : '$_[1]'; |
202 | my $code = 'sub { ' |
203 | . ($self->is_required ? |
204 | 'defined($_[1]) || confess "Attribute ($attr_name) is required, so cannot be set to undef";' |
205 | : '') |
206 | . ($self->should_coerce ? |
207 | 'my $val = $self->type_constraint->coercion->coerce($_[1]);' |
208 | : '') |
209 | . ($self->has_type_constraint ? |
210 | ('(defined $self->type_constraint->check(' . $value_name . '))' |
c07af9d2 |
211 | . '|| confess "Attribute ($attr_name) does not pass the type contraint (" . $self->type_constraint->name . ") with \'' . $value_name . '\'"' |
ca01a97b |
212 | . 'if defined ' . $value_name . ';') |
213 | : '') |
214 | . '$_[0]->{$attr_name} = ' . $value_name . ';' |
215 | . ($self->is_weak_ref ? |
216 | 'weaken($_[0]->{$attr_name});' |
217 | : '') |
8c9d74e7 |
218 | . ($self->has_trigger ? |
219 | '$self->trigger->($_[0], ' . $value_name . ');' |
220 | : '') |
ca01a97b |
221 | . ' }'; |
222 | my $sub = eval $code; |
223 | confess "Could not create writer for '$attr_name' because $@ \n code: $code" if $@; |
224 | return $sub; |
a15dff8d |
225 | } |
c0e30cf5 |
226 | |
d7f17ebb |
227 | sub generate_reader_method { |
228 | my ($self, $attr_name) = @_; |
ca01a97b |
229 | my $code = 'sub {' |
230 | . 'confess "Cannot assign a value to a read-only accessor" if @_ > 1;' |
231 | . ($self->is_lazy ? |
232 | '$_[0]->{$attr_name} = ($self->has_default ? $self->default($_[0]) : undef)' |
233 | . 'unless exists $_[0]->{$attr_name};' |
234 | : '') |
235 | . '$_[0]->{$attr_name};' |
236 | . '}'; |
237 | my $sub = eval $code; |
238 | confess "Could not create reader for '$attr_name' because $@ \n code: $code" if $@; |
239 | return $sub; |
d7f17ebb |
240 | } |
241 | |
c0e30cf5 |
242 | 1; |
243 | |
244 | __END__ |
245 | |
246 | =pod |
247 | |
248 | =head1 NAME |
249 | |
6ba6d68c |
250 | Moose::Meta::Attribute - The Moose attribute metaclass |
c0e30cf5 |
251 | |
252 | =head1 DESCRIPTION |
253 | |
e522431d |
254 | This is a subclass of L<Class::MOP::Attribute> with Moose specific |
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255 | extensions. |
256 | |
257 | For the most part, the only time you will ever encounter an |
258 | instance of this class is if you are doing some serious deep |
259 | introspection. To really understand this class, you need to refer |
260 | to the L<Class::MOP::Attribute> documentation. |
e522431d |
261 | |
c0e30cf5 |
262 | =head1 METHODS |
263 | |
6ba6d68c |
264 | =head2 Overridden methods |
265 | |
266 | These methods override methods in L<Class::MOP::Attribute> and add |
267 | Moose specific features. You can safely assume though that they |
268 | will behave just as L<Class::MOP::Attribute> does. |
269 | |
c0e30cf5 |
270 | =over 4 |
271 | |
272 | =item B<new> |
273 | |
d500266f |
274 | =item B<initialize_instance_slot> |
275 | |
a15dff8d |
276 | =item B<generate_accessor_method> |
277 | |
278 | =item B<generate_writer_method> |
279 | |
d7f17ebb |
280 | =item B<generate_reader_method> |
281 | |
a15dff8d |
282 | =back |
283 | |
6ba6d68c |
284 | =head2 Additional Moose features |
285 | |
286 | Moose attributes support type-contstraint checking, weak reference |
287 | creation and type coercion. |
288 | |
a15dff8d |
289 | =over 4 |
290 | |
291 | =item B<has_type_constraint> |
292 | |
6ba6d68c |
293 | Returns true if this meta-attribute has a type constraint. |
294 | |
a15dff8d |
295 | =item B<type_constraint> |
296 | |
6ba6d68c |
297 | A read-only accessor for this meta-attribute's type constraint. For |
298 | more information on what you can do with this, see the documentation |
299 | for L<Moose::Meta::TypeConstraint>. |
a15dff8d |
300 | |
6ba6d68c |
301 | =item B<is_weak_ref> |
a15dff8d |
302 | |
02a0fb52 |
303 | Returns true if this meta-attribute produces a weak reference. |
4b598ea3 |
304 | |
ca01a97b |
305 | =item B<is_required> |
306 | |
02a0fb52 |
307 | Returns true if this meta-attribute is required to have a value. |
ca01a97b |
308 | |
309 | =item B<is_lazy> |
310 | |
02a0fb52 |
311 | Returns true if this meta-attribute should be initialized lazily. |
ca01a97b |
312 | |
313 | NOTE: lazy attributes, B<must> have a C<default> field set. |
314 | |
34a66aa3 |
315 | =item B<should_coerce> |
4b598ea3 |
316 | |
02a0fb52 |
317 | Returns true if this meta-attribute should perform type coercion. |
6ba6d68c |
318 | |
8c9d74e7 |
319 | =item B<has_trigger> |
320 | |
02a0fb52 |
321 | Returns true if this meta-attribute has a trigger set. |
322 | |
8c9d74e7 |
323 | =item B<trigger> |
324 | |
02a0fb52 |
325 | This is a CODE reference which will be executed every time the |
326 | value of an attribute is assigned. The CODE ref will get two values, |
327 | the invocant and the new value. This can be used to handle I<basic> |
328 | bi-directional relations. |
329 | |
c0e30cf5 |
330 | =back |
331 | |
332 | =head1 BUGS |
333 | |
334 | All complex software has bugs lurking in it, and this module is no |
335 | exception. If you find a bug please either email me, or add the bug |
336 | to cpan-RT. |
337 | |
c0e30cf5 |
338 | =head1 AUTHOR |
339 | |
340 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
341 | |
342 | =head1 COPYRIGHT AND LICENSE |
343 | |
344 | Copyright 2006 by Infinity Interactive, Inc. |
345 | |
346 | L<http://www.iinteractive.com> |
347 | |
348 | This library is free software; you can redistribute it and/or modify |
349 | it under the same terms as Perl itself. |
350 | |
351 | =cut |