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1 | |
2 | package Class::MOP::Method::Constructor; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Carp 'confess'; |
8 | use Scalar::Util 'blessed', 'weaken', 'looks_like_number'; |
9 | |
565f0cbb |
10 | our $VERSION = '0.02'; |
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11 | our $AUTHORITY = 'cpan:STEVAN'; |
12 | |
565f0cbb |
13 | use base 'Class::MOP::Method::Generated'; |
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14 | |
15 | sub new { |
16 | my $class = shift; |
17 | my %options = @_; |
18 | |
ad315b75 |
19 | (blessed $options{metaclass} && $options{metaclass}->isa('Class::MOP::Class')) |
20 | || confess "You must pass a metaclass instance if you want to inline" |
21 | if $options{is_inline}; |
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22 | |
23 | my $self = bless { |
24 | # from our superclass |
c23184fc |
25 | '&!body' => undef, |
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26 | # specific to this subclass |
ad315b75 |
27 | '%!options' => $options{options} || {}, |
c23184fc |
28 | '$!associated_metaclass' => $options{metaclass}, |
565f0cbb |
29 | '$!is_inline' => ($options{is_inline} || 0), |
d90b42a6 |
30 | } => $class; |
31 | |
32 | # we don't want this creating |
33 | # a cycle in the code, if not |
34 | # needed |
c23184fc |
35 | weaken($self->{'$!associated_metaclass'}); |
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36 | |
565f0cbb |
37 | $self->initialize_body; |
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38 | |
39 | return $self; |
40 | } |
41 | |
565f0cbb |
42 | ## accessors |
c23184fc |
43 | |
565f0cbb |
44 | sub options { (shift)->{'%!options'} } |
45 | sub associated_metaclass { (shift)->{'$!associated_metaclass'} } |
c23184fc |
46 | |
565f0cbb |
47 | ## cached values ... |
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48 | |
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49 | sub meta_instance { |
50 | my $self = shift; |
51 | $self->{'$!meta_instance'} ||= $self->associated_metaclass->get_meta_instance; |
52 | } |
c23184fc |
53 | |
565f0cbb |
54 | sub attributes { |
55 | my $self = shift; |
56 | $self->{'@!attributes'} ||= [ $self->associated_metaclass->compute_all_applicable_attributes ] |
57 | } |
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58 | |
59 | ## method |
60 | |
565f0cbb |
61 | sub initialize_body { |
62 | my $self = shift; |
63 | my $method_name = 'generate_constructor_method'; |
64 | |
65 | $method_name .= '_inline' if $self->is_inline; |
66 | |
67 | $self->{'&!body'} = $self->$method_name; |
68 | } |
69 | |
70 | sub generate_constructor_method { |
71 | return sub { (shift)->meta->new_object(@_) } |
72 | } |
73 | |
74 | sub generate_constructor_method_inline { |
d90b42a6 |
75 | my $self = shift; |
565f0cbb |
76 | |
d90b42a6 |
77 | my $source = 'sub {'; |
78 | $source .= "\n" . 'my ($class, %params) = @_;'; |
565f0cbb |
79 | |
80 | $source .= "\n" . 'return $class->meta->new_object(%params)'; |
81 | $source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';'; |
82 | |
d90b42a6 |
83 | $source .= "\n" . 'my $instance = ' . $self->meta_instance->inline_create_instance('$class'); |
84 | $source .= ";\n" . (join ";\n" => map { |
85 | $self->_generate_slot_initializer($_) |
86 | } 0 .. (@{$self->attributes} - 1)); |
87 | $source .= ";\n" . 'return $instance'; |
88 | $source .= ";\n" . '}'; |
89 | warn $source if $self->options->{debug}; |
90 | |
91 | my $code; |
92 | { |
93 | # NOTE: |
94 | # create the nessecary lexicals |
95 | # to be picked up in the eval |
96 | my $attrs = $self->attributes; |
97 | |
98 | $code = eval $source; |
99 | confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@; |
100 | } |
565f0cbb |
101 | return $code; |
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102 | } |
103 | |
104 | sub _generate_slot_initializer { |
105 | my $self = shift; |
106 | my $index = shift; |
107 | |
108 | my $attr = $self->attributes->[$index]; |
109 | |
110 | my $default; |
111 | if ($attr->has_default) { |
112 | # NOTE: |
113 | # default values can either be CODE refs |
114 | # in which case we need to call them. Or |
115 | # they can be scalars (strings/numbers) |
116 | # in which case we can just deal with them |
117 | # in the code we eval. |
118 | if ($attr->is_default_a_coderef) { |
119 | $default = '$attrs->[' . $index . ']->default($instance)'; |
120 | } |
121 | else { |
122 | $default = $attr->default; |
123 | # make sure to quote strings ... |
124 | unless (looks_like_number($default)) { |
125 | $default = "'$default'"; |
126 | } |
127 | } |
128 | } |
129 | $self->meta_instance->inline_set_slot_value( |
130 | '$instance', |
131 | ("'" . $attr->name . "'"), |
132 | ('$params{\'' . $attr->init_arg . '\'}' . (defined $default ? (' || ' . $default) : '')) |
133 | ); |
134 | } |
135 | |
136 | 1; |
137 | |
138 | 1; |
139 | |
140 | __END__ |
141 | |
142 | =pod |
143 | |
144 | =head1 NAME |
145 | |
146 | Class::MOP::Method::Constructor - Method Meta Object for constructors |
147 | |
148 | =head1 SYNOPSIS |
149 | |
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150 | use Class::MOP::Method::Constructor; |
151 | |
152 | my $constructor = Class::MOP::Method::Constructor->new( |
153 | metaclass => $metaclass, |
154 | options => { |
155 | debug => 1, # this is all for now |
156 | }, |
157 | ); |
158 | |
159 | # calling the constructor ... |
160 | $constructor->body->($metaclass->name, %params); |
161 | |
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162 | =head1 DESCRIPTION |
163 | |
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164 | This is a subclass of C<Class::MOP::Method> which deals with |
165 | class constructors. |
166 | |
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167 | =head1 METHODS |
168 | |
169 | =over 4 |
170 | |
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171 | =item B<new (metaclass => $meta, options => \%options)> |
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172 | |
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173 | =item B<options> |
174 | |
175 | This returns the options HASH which is passed into C<new>. |
176 | |
177 | =item B<associated_metaclass> |
178 | |
179 | This returns the metaclass which is passed into C<new>. |
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180 | |
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181 | =item B<attributes> |
182 | |
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183 | This returns the list of attributes which are associated with the |
184 | metaclass which is passed into C<new>. |
185 | |
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186 | =item B<meta_instance> |
187 | |
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188 | This returns the meta instance which is associated with the |
189 | metaclass which is passed into C<new>. |
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190 | |
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191 | =item B<is_inline> |
192 | |
193 | This returns a boolean, but since constructors are very rarely |
194 | not inlined, this always returns true for now. |
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195 | |
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196 | =item B<initialize_body> |
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197 | |
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198 | This creates the code reference for the constructor itself. |
199 | |
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200 | =back |
201 | |
565f0cbb |
202 | =head2 Method Generators |
203 | |
204 | =over 4 |
205 | |
206 | =item B<generate_constructor_method> |
207 | |
208 | =item B<generate_constructor_method_inline> |
209 | |
210 | =back |
211 | |
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212 | =head1 AUTHORS |
213 | |
214 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
215 | |
216 | =head1 COPYRIGHT AND LICENSE |
217 | |
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218 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
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219 | |
220 | L<http://www.iinteractive.com> |
221 | |
222 | This library is free software; you can redistribute it and/or modify |
223 | it under the same terms as Perl itself. |
224 | |
225 | =cut |
226 | |