2 package Class::MOP::Method::Constructor;
8 use Scalar::Util 'blessed', 'weaken', 'looks_like_number';
10 our $VERSION = '0.75';
11 $VERSION = eval $VERSION;
12 our $AUTHORITY = 'cpan:STEVAN';
14 use base 'Class::MOP::Method::Generated';
20 (blessed $options{metaclass} && $options{metaclass}->isa('Class::MOP::Class'))
21 || confess "You must pass a metaclass instance if you want to inline"
22 if $options{is_inline};
24 ($options{package_name} && $options{name})
25 || confess "You must supply the package_name and name parameters $Class::MOP::Method::UPGRADE_ERROR_TEXT";
27 my $self = $class->_new(\%options);
29 # we don't want this creating
30 # a cycle in the code, if not
32 weaken($self->{'associated_metaclass'});
34 $self->initialize_body;
41 my $options = @_ == 1 ? $_[0] : {@_};
46 'package_name' => $options->{package_name},
47 'name' => $options->{name},
48 # specific to this subclass
49 'options' => $options->{options} || {},
50 'associated_metaclass' => $options->{metaclass},
51 'is_inline' => ($options->{is_inline} || 0),
55 sub can_be_inlined { 1 }
59 sub options { (shift)->{'options'} }
60 sub associated_metaclass { (shift)->{'associated_metaclass'} }
66 $self->{'meta_instance'} ||= $self->associated_metaclass->get_meta_instance;
71 $self->{'attributes'} ||= [ $self->associated_metaclass->compute_all_applicable_attributes ]
78 my $method_name = 'generate_constructor_method';
80 $method_name .= '_inline' if $self->is_inline;
82 $self->{'body'} = $self->$method_name;
85 sub generate_constructor_method {
86 return sub { Class::MOP::Class->initialize(shift)->new_object(@_) }
89 sub generate_constructor_method_inline {
95 $source .= "\n" . 'my $class = shift;';
97 $source .= "\n" . 'return Class::MOP::Class->initialize($class)->new_object(@_)';
98 $source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';';
100 $source .= "\n" . 'my $params = @_ == 1 ? $_[0] : {@_};';
102 $source .= "\n" . 'my $instance = ' . $self->meta_instance->inline_create_instance('$class');
103 $source .= ";\n" . (join ";\n" => map {
104 $self->_generate_slot_initializer($_, $close_over)
105 } 0 .. (@{$self->attributes} - 1));
106 $source .= ";\n" . 'return $instance';
107 $source .= ";\n" . '}';
108 warn $source if $self->options->{debug};
113 # create the nessecary lexicals
114 # to be picked up in the eval
116 $code = $self->_eval_closure(
120 confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@;
125 sub _generate_slot_initializer {
130 my $attr = $self->attributes->[$index];
133 if ($attr->has_default) {
135 # default values can either be CODE refs
136 # in which case we need to call them. Or
137 # they can be scalars (strings/numbers)
138 # in which case we can just deal with them
139 # in the code we eval.
140 if ($attr->is_default_a_coderef) {
141 my $idx = @{$close->{'@defaults'}||=[]};
142 push(@{$close->{'@defaults'}}, $attr->default);
143 $default = '$defaults[' . $idx . ']->($instance)';
146 $default = $attr->default;
147 # make sure to quote strings ...
148 unless (looks_like_number($default)) {
149 $default = "'$default'";
152 } elsif( $attr->has_builder ) {
153 $default = '$instance->'.$attr->builder;
156 if ( defined $attr->init_arg ) {
158 'if(exists $params->{\'' . $attr->init_arg . '\'}){' . "\n" .
159 $self->meta_instance->inline_set_slot_value(
161 ("'" . $attr->name . "'"),
162 '$params->{\'' . $attr->init_arg . '\'}' ) . "\n" .
163 '} ' . (!defined $default ? '' : 'else {' . "\n" .
164 $self->meta_instance->inline_set_slot_value(
166 ("'" . $attr->name . "'"),
170 } elsif ( defined $default ) {
172 $self->meta_instance->inline_set_slot_value(
174 ("'" . $attr->name . "'"),
188 Class::MOP::Method::Constructor - Method Meta Object for constructors
192 use Class::MOP::Method::Constructor;
194 my $constructor = Class::MOP::Method::Constructor->new(
195 metaclass => $metaclass,
197 debug => 1, # this is all for now
201 # calling the constructor ...
202 $constructor->body->execute($metaclass->name, %params);
206 This is a subclass of C<Class::MOP::Method> which deals with
207 class constructors. This is used when making a class immutable
208 to generate an optimized constructor.
214 =item B<new (metaclass => $meta, options => \%options)>
218 This returns the options HASH which is passed into C<new>.
220 =item B<associated_metaclass>
222 This returns the metaclass which is passed into C<new>.
226 This returns the list of attributes which are associated with the
227 metaclass which is passed into C<new>.
229 =item B<meta_instance>
231 This returns the meta instance which is associated with the
232 metaclass which is passed into C<new>.
236 This returns a boolean, but since constructors are very rarely
237 not inlined, this always returns true for now.
239 =item B<can_be_inlined>
241 This method always returns true in this class. It exists so that
242 subclasses (like in Moose) can override and do some sort of checking
243 to determine whether or not inlining the constructor is safe.
245 =item B<initialize_body>
247 This creates the code reference for the constructor itself.
251 =head2 Method Generators
255 =item B<generate_constructor_method>
257 =item B<generate_constructor_method_inline>
263 Stevan Little E<lt>stevan@iinteractive.comE<gt>
265 =head1 COPYRIGHT AND LICENSE
267 Copyright 2006-2008 by Infinity Interactive, Inc.
269 L<http://www.iinteractive.com>
271 This library is free software; you can redistribute it and/or modify
272 it under the same terms as Perl itself.