Commit | Line | Data |
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} } |
21 | sub default { $_[0]->{default} } |
22 | sub predicate { $_[0]->{predicate} } |
23 | sub clearer { $_[0]->{clearer} } |
24 | sub handles { $_[0]->{handles} } |
25 | sub weak_ref { $_[0]->{weak_ref} } |
26 | sub init_arg { $_[0]->{init_arg} } |
27 | sub type_constraint { $_[0]->{type_constraint} } |
c3398f5b |
28 | |
29 | sub generate_accessor { |
30 | my $attribute = shift; |
31 | |
a707f587 |
32 | my $name = $attribute->{name}; |
33 | my $key = $attribute->{init_arg}; |
34 | my $default = $attribute->{default}; |
35 | my $trigger = $attribute->{trigger}; |
36 | my $type = $attribute->{type_constraint}; |
37 | |
38 | my $constraint = sub { |
39 | return unless $type; |
40 | |
41 | my $checker = Mouse::TypeRegistry->optimized_constraints->{$type}; |
42 | return $checker if $checker; |
43 | |
44 | confess "Unable to parse type constraint '$type'"; |
45 | }->(); |
c3398f5b |
46 | |
47 | my $accessor = 'sub { |
48 | my $self = shift;'; |
49 | |
50 | if ($attribute->{is} eq 'rw') { |
51 | $accessor .= 'if (@_) { |
a707f587 |
52 | local $_ = $_[0];'; |
53 | |
54 | if ($constraint) { |
55 | $accessor .= 'Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $_") unless $constraint->();' |
56 | } |
57 | |
58 | $accessor .= '$self->{$key} = $_;'; |
c3398f5b |
59 | |
60 | if ($attribute->{weak_ref}) { |
61 | $accessor .= 'Scalar::Util::weaken($self->{$key});'; |
62 | } |
63 | |
64 | if ($trigger) { |
a707f587 |
65 | $accessor .= '$trigger->($self, $_, $attribute);'; |
c3398f5b |
66 | } |
67 | |
68 | $accessor .= '}'; |
69 | } |
70 | else { |
71 | } |
72 | |
73 | if ($attribute->{lazy}) { |
74 | $accessor .= '$self->{$key} = '; |
75 | $accessor .= ref($attribute->{default}) eq 'CODE' |
76 | ? '$default->($self)' |
77 | : '$default'; |
78 | $accessor .= ' if !exists($self->{$key});'; |
79 | } |
80 | |
81 | $accessor .= 'return $self->{$key} |
82 | }'; |
83 | |
84 | return eval $accessor; |
85 | } |
86 | |
87 | sub generate_predicate { |
88 | my $attribute = shift; |
89 | my $key = $attribute->{init_arg}; |
90 | |
91 | my $predicate = 'sub { exists($_[0]->{$key}) }'; |
92 | |
93 | return eval $predicate; |
94 | } |
95 | |
96 | sub generate_clearer { |
97 | my $attribute = shift; |
98 | my $key = $attribute->{init_arg}; |
99 | |
100 | my $predicate = 'sub { delete($_[0]->{$key}) }'; |
101 | |
102 | return eval $predicate; |
103 | } |
104 | |
105 | sub generate_handles { |
106 | my $attribute = shift; |
107 | my $reader = $attribute->{name}; |
108 | |
109 | my %method_map; |
110 | |
111 | for my $local_method (keys %{ $attribute->{handles} }) { |
112 | my $remote_method = $attribute->{handles}{$local_method}; |
113 | |
114 | my $method = 'sub { |
115 | my $self = shift; |
116 | $self->$reader->$remote_method(@_) |
117 | }'; |
118 | |
119 | $method_map{$local_method} = eval $method; |
120 | } |
121 | |
122 | return \%method_map; |
123 | } |
124 | |
125 | sub create { |
126 | my ($self, $class, $name, %args) = @_; |
127 | |
128 | confess "You must specify a default for lazy attribute '$name'" |
129 | if $args{lazy} && !exists($args{default}); |
130 | |
131 | confess "Trigger is not allowed on read-only attribute '$name'" |
132 | if $args{trigger} && $args{is} ne 'rw'; |
133 | |
134 | confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])" |
135 | if ref($args{default}) |
136 | && ref($args{default}) ne 'CODE'; |
137 | |
138 | $args{handles} = { map { $_ => $_ } @{ $args{handles} } } |
139 | if $args{handles} |
140 | && ref($args{handles}) eq 'ARRAY'; |
141 | |
142 | confess "You must pass a HASH or ARRAY to handles" |
143 | if exists($args{handles}) |
144 | && ref($args{handles}) ne 'HASH'; |
145 | |
186657a9 |
146 | $args{type_constraint} = delete $args{isa}; |
147 | |
c3398f5b |
148 | my $attribute = $self->new(%args, name => $name, class => $class); |
149 | my $meta = $class->meta; |
150 | |
b2500191 |
151 | $meta->add_attribute($attribute); |
152 | |
c3398f5b |
153 | # install an accessor |
154 | if ($attribute->{is} eq 'rw' || $attribute->{is} eq 'ro') { |
155 | my $accessor = $attribute->generate_accessor; |
156 | no strict 'refs'; |
157 | *{ $class . '::' . $name } = $accessor; |
158 | } |
159 | |
c3398f5b |
160 | for my $method (qw/predicate clearer/) { |
161 | if (exists $attribute->{$method}) { |
162 | my $generator = "generate_$method"; |
163 | my $coderef = $attribute->$generator; |
164 | no strict 'refs'; |
165 | *{ $class . '::' . $attribute->{$method} } = $coderef; |
166 | } |
167 | } |
168 | |
169 | if ($attribute->{handles}) { |
170 | my $method_map = $attribute->generate_handles; |
171 | for my $method_name (keys %$method_map) { |
172 | no strict 'refs'; |
173 | *{ $class . '::' . $method_name } = $method_map->{$method_name}; |
174 | } |
175 | } |
176 | |
177 | return $attribute; |
178 | } |
179 | |
180 | 1; |
181 | |
182 | __END__ |
183 | |
184 | =head1 NAME |
185 | |
186 | Mouse::Attribute - attribute metaclass |
187 | |
188 | =head1 METHODS |
189 | |
190 | =head2 new %args -> Mouse::Attribute |
191 | |
192 | Instantiates a new Mouse::Attribute. Does nothing else. |
193 | |
194 | =head2 create OwnerClass, AttributeName, %args -> Mouse::Attribute |
195 | |
196 | Creates a new attribute in OwnerClass. Accessors and helper methods are |
197 | installed. Some error checking is done. |
198 | |
199 | =head2 name -> AttributeName |
200 | |
201 | =head2 class -> OwnerClass |
202 | |
203 | =head2 default -> Value |
204 | |
205 | =head2 predicate -> MethodName |
206 | |
207 | =head2 clearer -> MethodName |
208 | |
209 | =head2 handles -> { LocalName => RemoteName } |
210 | |
211 | =head2 weak_ref -> Bool |
212 | |
213 | =head2 init_arg -> Str |
214 | |
215 | Informational methods. |
216 | |
217 | =head2 generate_accessor -> CODE |
218 | |
219 | Creates a new code reference for the attribute's accessor. |
220 | |
221 | =head2 generate_predicate -> CODE |
222 | |
223 | Creates a new code reference for the attribute's predicate. |
224 | |
225 | =head2 generate_clearer -> CODE |
226 | |
227 | Creates a new code reference for the attribute's clearer. |
228 | |
229 | =head2 generate_handles -> { MethodName => CODE } |
230 | |
231 | Creates a new code reference for each of the attribute's handles methods. |
232 | |
233 | =cut |
234 | |