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1 | |
2 | package Class::MOP::Attribute; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
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7 | use Carp 'confess'; |
8 | use Scalar::Util 'blessed'; |
9 | |
10 | use Class::MOP::Class; |
11 | use Class::MOP::Method; |
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12 | |
13 | our $VERSION = '0.01'; |
14 | |
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15 | sub meta { Class::MOP::Class->initialize($_[0]) } |
16 | |
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17 | sub new { |
18 | my $class = shift; |
19 | my $name = shift; |
20 | my %options = @_; |
21 | |
cbd9f942 |
22 | (defined $name && $name) |
8b978dd5 |
23 | || confess "You must provide a name for the attribute"; |
2eb717d5 |
24 | (!exists $options{reader} && !exists $options{writer}) |
25 | || confess "You cannot declare an accessor and reader and/or writer functions" |
26 | if exists $options{accessor}; |
27 | |
8b978dd5 |
28 | bless { |
29 | name => $name, |
30 | accessor => $options{accessor}, |
31 | reader => $options{reader}, |
32 | writer => $options{writer}, |
33 | init_arg => $options{init_arg}, |
34 | default => $options{default} |
35 | } => $class; |
36 | } |
37 | |
38 | sub name { (shift)->{name} } |
39 | |
40 | sub has_accessor { (shift)->{accessor} ? 1 : 0 } |
41 | sub accessor { (shift)->{accessor} } |
42 | |
43 | sub has_reader { (shift)->{reader} ? 1 : 0 } |
44 | sub reader { (shift)->{reader} } |
45 | |
46 | sub has_writer { (shift)->{writer} ? 1 : 0 } |
47 | sub writer { (shift)->{writer} } |
48 | |
49 | sub has_init_arg { (shift)->{init_arg} ? 1 : 0 } |
50 | sub init_arg { (shift)->{init_arg} } |
51 | |
52 | sub has_default { (shift)->{default} ? 1 : 0 } |
53 | sub default { (shift)->{default} } |
54 | |
2eb717d5 |
55 | sub install_accessors { |
56 | my ($self, $class) = @_; |
57 | (blessed($class) && $class->isa('Class::MOP::Class')) |
58 | || confess "You must pass a Class::MOP::Class instance (or a subclass)"; |
59 | |
60 | if ($self->has_accessor()) { |
61 | $class->add_method($self->accessor() => Class::MOP::Attribute::Accessor->wrap(sub { |
62 | $_[0]->{$self->name} = $_[1] if scalar(@_) == 2; |
63 | $_[0]->{$self->name}; |
64 | })); |
65 | } |
66 | else { |
67 | if ($self->has_reader()) { |
68 | $class->add_method($self->reader() => Class::MOP::Attribute::Accessor->wrap(sub { |
69 | $_[0]->{$self->name}; |
70 | })); |
71 | } |
72 | if ($self->has_writer()) { |
73 | $class->add_method($self->writer() => Class::MOP::Attribute::Accessor->wrap(sub { |
74 | $_[0]->{$self->name} = $_[1]; |
75 | return; |
76 | })); |
77 | } |
78 | } |
79 | } |
80 | |
81 | sub remove_accessors { |
82 | my ($self, $class) = @_; |
83 | (blessed($class) && $class->isa('Class::MOP::Class')) |
84 | || confess "You must pass a Class::MOP::Class instance (or a subclass)"; |
85 | |
86 | if ($self->has_accessor()) { |
87 | my $method = $class->get_method($self->accessor); |
88 | $class->remove_method($self->accessor) |
89 | if (blessed($method) && $method->isa('Class::MOP::Attribute::Accessor')); |
90 | } |
91 | else { |
92 | if ($self->has_reader()) { |
93 | my $method = $class->get_method($self->reader); |
94 | $class->remove_method($self->reader) |
95 | if (blessed($method) && $method->isa('Class::MOP::Attribute::Accessor')); |
96 | } |
97 | if ($self->has_writer()) { |
98 | my $method = $class->get_method($self->writer); |
99 | $class->remove_method($self->writer) |
100 | if (blessed($method) && $method->isa('Class::MOP::Attribute::Accessor')); |
101 | } |
102 | } |
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103 | } |
104 | |
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105 | package Class::MOP::Attribute::Accessor; |
106 | |
107 | use strict; |
108 | use warnings; |
109 | |
110 | our $VERSION = '0.01'; |
111 | |
112 | our @ISA = ('Class::MOP::Method'); |
113 | |
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114 | 1; |
115 | |
116 | __END__ |
117 | |
118 | =pod |
119 | |
120 | =head1 NAME |
121 | |
122 | Class::MOP::Attribute - Attribute Meta Object |
123 | |
124 | =head1 SYNOPSIS |
125 | |
126 | Class::MOP::Attribute->new('$foo' => ( |
127 | accessor => 'foo', # dual purpose get/set accessor |
128 | init_arg => '-foo', # class->new will look for a -foo key |
129 | default => 'BAR IS BAZ!' # if no -foo key is provided, use this |
130 | )); |
131 | |
132 | Class::MOP::Attribute->new('$.bar' => ( |
133 | reader => 'bar', # getter |
134 | writer => 'set_bar', # setter |
135 | init_arg => '-bar', # class->new will look for a -bar key |
136 | # no default value means it is undef |
137 | )); |
138 | |
139 | =head1 DESCRIPTION |
140 | |
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141 | The Attribute Protocol is almost entirely an invention of this module. This is |
142 | because Perl 5 does not have consistent notion of what is an attribute |
143 | of a class. There are so many ways in which this is done, and very few |
144 | (if any) are discoverable by this module. |
145 | |
146 | So, all that said, this module attempts to inject some order into this |
147 | chaos, by introducing a more consistent approach. |
148 | |
149 | =head1 METHODS |
150 | |
151 | =head2 Creation |
152 | |
153 | =over 4 |
154 | |
155 | =item B<new ($name, %accessor_description, $class_initialization_arg, $default_value)> |
156 | |
157 | =back |
158 | |
159 | =head2 Informational |
160 | |
161 | =over 4 |
162 | |
163 | =item B<name> |
164 | |
165 | =item B<accessor> |
166 | |
167 | =item B<reader> |
168 | |
169 | =item B<writer> |
170 | |
171 | =item B<init_arg> |
172 | |
173 | =item B<default> |
174 | |
175 | =back |
176 | |
177 | =head2 Informational predicates |
178 | |
179 | =over 4 |
180 | |
181 | =item B<has_accessor> |
182 | |
183 | Returns true if this attribute uses a get/set accessor, and false |
184 | otherwise |
185 | |
186 | =item B<has_reader> |
187 | |
188 | Returns true if this attribute has a reader, and false otherwise |
189 | |
190 | =item B<has_writer> |
191 | |
192 | Returns true if this attribute has a writer, and false otherwise |
193 | |
194 | =item B<has_init_arg> |
195 | |
196 | Returns true if this attribute has a class intialization argument, and |
197 | false otherwise |
198 | |
199 | =item B<has_default> |
200 | |
201 | Returns true if this attribute has a default value, and false |
202 | otherwise. |
203 | |
204 | =back |
205 | |
206 | =head2 Attribute Accessor generation |
207 | |
208 | =over 4 |
209 | |
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210 | =item B<install_accessors ($class)> |
211 | |
212 | This allows the attribute to generate and install code for it's own |
213 | accessor methods. This is called by C<Class::MOP::Class::add_attribute>. |
214 | |
215 | =item B<remove_accessors ($class)> |
216 | |
217 | This allows the attribute to remove the method for it's own |
218 | accessor. This is called by C<Class::MOP::Class::remove_attribute>. |
219 | |
220 | =back |
221 | |
222 | =head2 Introspection |
223 | |
224 | =over 4 |
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225 | |
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226 | =item B<meta> |
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227 | |
228 | =back |
229 | |
8b978dd5 |
230 | =head1 AUTHOR |
231 | |
232 | Stevan Little E<gt>stevan@iinteractive.comE<lt> |
233 | |
234 | =head1 COPYRIGHT AND LICENSE |
235 | |
236 | Copyright 2006 by Infinity Interactive, Inc. |
237 | |
238 | L<http://www.iinteractive.com> |
239 | |
240 | This library is free software; you can redistribute it and/or modify |
241 | it under the same terms as Perl itself. |
242 | |
243 | =cut |