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c3398f5b |
1 | #!/usr/bin/env perl |
2 | package Mouse::Attribute; |
3 | use strict; |
4 | use warnings; |
5 | |
6 | use Carp 'confess'; |
7 | |
8 | sub new { |
9 | my $class = shift; |
10 | my %args = @_; |
11 | |
7ee01d77 |
12 | $args{init_arg} = $args{name} |
13 | unless exists $args{init_arg}; |
c3398f5b |
14 | $args{is} ||= ''; |
15 | |
16 | bless \%args, $class; |
17 | } |
18 | |
186657a9 |
19 | sub name { $_[0]->{name} } |
20 | sub class { $_[0]->{class} } |
2434d21b |
21 | sub _is_metadata { $_[0]->{is} } |
22 | sub is_required { $_[0]->{required} } |
186657a9 |
23 | sub default { $_[0]->{default} } |
2434d21b |
24 | sub is_lazy { $_[0]->{lazy} } |
186657a9 |
25 | sub predicate { $_[0]->{predicate} } |
26 | sub clearer { $_[0]->{clearer} } |
27 | sub handles { $_[0]->{handles} } |
28 | sub weak_ref { $_[0]->{weak_ref} } |
29 | sub init_arg { $_[0]->{init_arg} } |
30 | sub type_constraint { $_[0]->{type_constraint} } |
de9a434a |
31 | sub trigger { $_[0]->{trigger} } |
32 | sub builder { $_[0]->{builder} } |
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33 | |
ccea8101 |
34 | sub has_default { exists $_[0]->{default} } |
35 | sub has_predicate { exists $_[0]->{predicate} } |
36 | sub has_clearer { exists $_[0]->{clearer} } |
37 | sub has_handles { exists $_[0]->{handles} } |
38 | sub has_weak_ref { exists $_[0]->{weak_ref} } |
39 | sub has_init_arg { exists $_[0]->{init_arg} } |
40 | sub has_type_constraint { exists $_[0]->{type_constraint} } |
de9a434a |
41 | sub has_trigger { exists $_[0]->{trigger} } |
42 | sub has_builder { exists $_[0]->{builder} } |
ccea8101 |
43 | |
c3398f5b |
44 | sub generate_accessor { |
45 | my $attribute = shift; |
46 | |
2434d21b |
47 | my $name = $attribute->name; |
48 | my $key = $attribute->init_arg; |
49 | my $default = $attribute->default; |
50 | my $trigger = $attribute->trigger; |
51 | my $type = $attribute->type_constraint; |
5aa30ced |
52 | my $constraint = $attribute->find_type_constraint; |
c3398f5b |
53 | |
54 | my $accessor = 'sub { |
55 | my $self = shift;'; |
56 | |
2434d21b |
57 | if ($attribute->_is_metadata eq 'rw') { |
c3398f5b |
58 | $accessor .= 'if (@_) { |
a707f587 |
59 | local $_ = $_[0];'; |
60 | |
61 | if ($constraint) { |
1f2b4780 |
62 | $accessor .= 'do { |
63 | my $display = defined($_) ? $_ : "undef"; |
64 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display") unless $constraint->(); |
65 | };' |
a707f587 |
66 | } |
67 | |
68 | $accessor .= '$self->{$key} = $_;'; |
c3398f5b |
69 | |
2434d21b |
70 | if ($attribute->weak_ref) { |
c3398f5b |
71 | $accessor .= 'Scalar::Util::weaken($self->{$key});'; |
72 | } |
73 | |
74 | if ($trigger) { |
a707f587 |
75 | $accessor .= '$trigger->($self, $_, $attribute);'; |
c3398f5b |
76 | } |
77 | |
78 | $accessor .= '}'; |
79 | } |
80 | else { |
81 | } |
82 | |
2434d21b |
83 | if ($attribute->is_lazy) { |
c3398f5b |
84 | $accessor .= '$self->{$key} = '; |
2434d21b |
85 | $accessor .= ref($default) eq 'CODE' |
c3398f5b |
86 | ? '$default->($self)' |
87 | : '$default'; |
88 | $accessor .= ' if !exists($self->{$key});'; |
89 | } |
90 | |
91 | $accessor .= 'return $self->{$key} |
92 | }'; |
93 | |
94 | return eval $accessor; |
95 | } |
96 | |
97 | sub generate_predicate { |
98 | my $attribute = shift; |
2434d21b |
99 | my $key = $attribute->init_arg; |
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100 | |
101 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
102 | |
103 | return eval $predicate; |
104 | } |
105 | |
106 | sub generate_clearer { |
107 | my $attribute = shift; |
2434d21b |
108 | my $key = $attribute->init_arg; |
c3398f5b |
109 | |
110 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
111 | |
112 | return eval $predicate; |
113 | } |
114 | |
115 | sub generate_handles { |
116 | my $attribute = shift; |
2434d21b |
117 | my $reader = $attribute->name; |
c3398f5b |
118 | |
119 | my %method_map; |
120 | |
2434d21b |
121 | for my $local_method (keys %{ $attribute->handles }) { |
122 | my $remote_method = $attribute->handles->{$local_method}; |
c3398f5b |
123 | |
124 | my $method = 'sub { |
125 | my $self = shift; |
126 | $self->$reader->$remote_method(@_) |
127 | }'; |
128 | |
129 | $method_map{$local_method} = eval $method; |
130 | } |
131 | |
132 | return \%method_map; |
133 | } |
134 | |
135 | sub create { |
136 | my ($self, $class, $name, %args) = @_; |
137 | |
138 | confess "You must specify a default for lazy attribute '$name'" |
139 | if $args{lazy} && !exists($args{default}); |
140 | |
141 | confess "Trigger is not allowed on read-only attribute '$name'" |
142 | if $args{trigger} && $args{is} ne 'rw'; |
143 | |
144 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
145 | if ref($args{default}) |
146 | && ref($args{default}) ne 'CODE'; |
147 | |
148 | $args{handles} = { map { $_ => $_ } @{ $args{handles} } } |
149 | if $args{handles} |
150 | && ref($args{handles}) eq 'ARRAY'; |
151 | |
152 | confess "You must pass a HASH or ARRAY to handles" |
153 | if exists($args{handles}) |
154 | && ref($args{handles}) ne 'HASH'; |
155 | |
186657a9 |
156 | $args{type_constraint} = delete $args{isa}; |
157 | |
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158 | my $attribute = $self->new(%args, name => $name, class => $class); |
159 | my $meta = $class->meta; |
160 | |
b2500191 |
161 | $meta->add_attribute($attribute); |
162 | |
c3398f5b |
163 | # install an accessor |
2434d21b |
164 | if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') { |
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165 | my $accessor = $attribute->generate_accessor; |
166 | no strict 'refs'; |
167 | *{ $class . '::' . $name } = $accessor; |
168 | } |
169 | |
c3398f5b |
170 | for my $method (qw/predicate clearer/) { |
2434d21b |
171 | my $predicate = "has_$method"; |
172 | if ($attribute->$predicate) { |
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173 | my $generator = "generate_$method"; |
174 | my $coderef = $attribute->$generator; |
175 | no strict 'refs'; |
2434d21b |
176 | *{ $class . '::' . $attribute->$method } = $coderef; |
c3398f5b |
177 | } |
178 | } |
179 | |
2434d21b |
180 | if ($attribute->has_handles) { |
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181 | my $method_map = $attribute->generate_handles; |
182 | for my $method_name (keys %$method_map) { |
183 | no strict 'refs'; |
184 | *{ $class . '::' . $method_name } = $method_map->{$method_name}; |
185 | } |
186 | } |
187 | |
188 | return $attribute; |
189 | } |
190 | |
5aa30ced |
191 | sub find_type_constraint { |
192 | my $self = shift; |
193 | my $type = $self->type_constraint; |
194 | |
195 | return unless $type; |
196 | |
197 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
198 | return $checker if $checker; |
199 | |
200 | confess "Unable to parse type constraint '$type'"; |
201 | } |
202 | |
203 | sub verify_type_constraint { |
204 | my $self = shift; |
205 | local $_ = shift; |
206 | |
207 | my $type = $self->type_constraint |
208 | or return 1; |
209 | my $constraint = $self->find_type_constraint |
210 | or return 1; |
211 | |
212 | return 1 if $constraint->($_); |
213 | |
214 | my $name = $self->name; |
1f2b4780 |
215 | local $_ = "undef" unless defined($_); |
5aa30ced |
216 | Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $_"); |
217 | } |
218 | |
c3398f5b |
219 | 1; |
220 | |
221 | __END__ |
222 | |
223 | =head1 NAME |
224 | |
225 | Mouse::Attribute - attribute metaclass |
226 | |
227 | =head1 METHODS |
228 | |
229 | =head2 new %args -> Mouse::Attribute |
230 | |
231 | Instantiates a new Mouse::Attribute. Does nothing else. |
232 | |
233 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Attribute |
234 | |
235 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
236 | installed. Some error checking is done. |
237 | |
238 | =head2 name -> AttributeName |
239 | |
240 | =head2 class -> OwnerClass |
241 | |
242 | =head2 default -> Value |
243 | |
244 | =head2 predicate -> MethodName |
245 | |
246 | =head2 clearer -> MethodName |
247 | |
248 | =head2 handles -> { LocalName => RemoteName } |
249 | |
250 | =head2 weak_ref -> Bool |
251 | |
252 | =head2 init_arg -> Str |
253 | |
254 | Informational methods. |
255 | |
256 | =head2 generate_accessor -> CODE |
257 | |
258 | Creates a new code reference for the attribute's accessor. |
259 | |
260 | =head2 generate_predicate -> CODE |
261 | |
262 | Creates a new code reference for the attribute's predicate. |
263 | |
264 | =head2 generate_clearer -> CODE |
265 | |
266 | Creates a new code reference for the attribute's clearer. |
267 | |
268 | =head2 generate_handles -> { MethodName => CODE } |
269 | |
270 | Creates a new code reference for each of the attribute's handles methods. |
271 | |
272 | =cut |
273 | |