2 package Moose::Meta::Method::Constructor;
8 use Scalar::Util 'blessed', 'weaken', 'looks_like_number';
10 our $VERSION = '0.01';
11 our $AUTHORITY = 'cpan:STEVAN';
13 use base 'Moose::Meta::Method';
19 (exists $options{options} && ref $options{options} eq 'HASH')
20 || confess "You must pass a hash of options";
25 # specific to this subclass
26 '%!options' => $options{options},
27 '$!meta_instance' => $options{metaclass}->get_meta_instance,
28 '@!attributes' => [ $options{metaclass}->compute_all_applicable_attributes ],
30 '$!associated_metaclass' => $options{metaclass},
33 # we don't want this creating
34 # a cycle in the code, if not
36 weaken($self->{'$!associated_metaclass'});
38 $self->intialize_body;
45 sub options { (shift)->{'%!options'} }
46 sub meta_instance { (shift)->{'$!meta_instance'} }
47 sub attributes { (shift)->{'@!attributes'} }
49 sub associated_metaclass { (shift)->{'$!associated_metaclass'} }
56 # the %options should also include a both
57 # a call 'initializer' and call 'SUPER::'
58 # options, which should cover approx 90%
59 # of the possible use cases (even if it
60 # requires some adaption on the part of
61 # the author, after all, nothing is free)
63 $source .= "\n" . 'my $class = shift;';
65 $source .= "\n" . 'return $class->Moose::Object::new(@_)';
66 $source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';';
68 $source .= "\n" . 'my %params = (scalar @_ == 1) ? %{$_[0]} : @_;';
70 $source .= "\n" . 'my $instance = ' . $self->meta_instance->inline_create_instance('$class');
72 $source .= ";\n" . (join ";\n" => map {
73 $self->_generate_slot_initializer($_)
74 } 0 .. (@{$self->attributes} - 1));
76 $source .= ";\n" . $self->_generate_BUILDALL();
78 $source .= ";\n" . 'return $instance';
79 $source .= ";\n" . '}';
80 warn $source if $self->options->{debug};
85 # create the nessecary lexicals
86 # to be picked up in the eval
87 my $attrs = $self->attributes;
90 confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@;
92 $self->{'&!body'} = $code;
95 sub _generate_BUILDALL {
98 foreach my $method (reverse $self->associated_metaclass->find_all_methods_by_name('BUILD')) {
99 push @BUILD_calls => '$instance->' . $method->{class} . '::BUILD(\%params)';
101 return join "\n" => @BUILD_calls;
104 sub _generate_slot_initializer {
108 my $attr = $self->attributes->[$index];
110 my @source = ('## ' . $attr->name);
112 if ($attr->is_required && !$attr->has_default) {
113 push @source => ('(exists $params{\'' . $attr->init_arg . '\'}) ' .
114 '|| confess "Attribute (' . $attr->name . ') is required";');
117 if ($attr->has_default && !$attr->is_lazy) {
119 push @source => 'if (exists $params{\'' . $attr->init_arg . '\'}) {';
121 push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
122 if ($attr->has_type_constraint) {
123 push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');
125 if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
126 push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');
128 push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$val');
130 push @source => $self->_generate_slot_assignment($attr, '$val');
133 push @source => "} else {";
135 my $default = $self->_generate_default_value($attr, $index);
137 push @source => ('my $val = ' . $default . ';');
138 push @source => $self->_generate_type_constraint_check(
140 ('$attrs->[' . $index . ']->type_constraint'),
142 ) if $attr->has_type_constraint;
143 push @source => $self->_generate_slot_assignment($attr, $default);
148 push @source => '(exists $params{\'' . $attr->init_arg . '\'}) && do {';
150 push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
151 if ($attr->has_type_constraint) {
152 push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');
154 if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
155 push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');
157 push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$val');
159 push @source => $self->_generate_slot_assignment($attr, '$val');
164 return join "\n" => @source;
167 sub _generate_slot_assignment {
168 my ($self, $attr, $value) = @_;
170 $self->meta_instance->inline_set_slot_value(
172 ("'" . $attr->name . "'"),
177 if ($attr->is_weak_ref) {
180 $self->meta_instance->inline_weaken_slot_value(
182 ("'" . $attr->name . "'")
184 ' if ref ' . $value . ';'
191 sub _generate_type_coercion {
192 my ($self, $attr, $type_constraint_name, $value_name, $return_value_name) = @_;
193 return ($return_value_name . ' = ' . $type_constraint_name . '->coerce(' . $value_name . ');');
196 sub _generate_type_constraint_check {
197 my ($self, $attr, $type_constraint_name, $value_name) = @_;
199 'defined(' . $type_constraint_name . '->_compiled_type_constraint->(' . $value_name . '))'
200 . "\n\t" . '|| confess "Attribute (' . $attr->name . ') does not pass the type constraint ('
201 . $attr->type_constraint->name . ') with " . (defined() ? "' . $value_name . '" : "undef");'
205 sub _generate_default_value {
206 my ($self, $attr, $index) = @_;
208 # default values can either be CODE refs
209 # in which case we need to call them. Or
210 # they can be scalars (strings/numbers)
211 # in which case we can just deal with them
212 # in the code we eval.
213 if ($attr->is_default_a_coderef) {
214 return '$attrs->[' . $index . ']->default($instance)';
217 my $default = $attr->default;
218 # make sure to quote strings ...
219 unless (looks_like_number($default)) {
220 $default = "'$default'";
237 Moose::Meta::Method::Constructor - Method Meta Object for constructors
241 This is a subclass of L<Class::MOP::Method> which handles
242 constructing an approprate Constructor methods. This is primarily
243 used in the making of immutable metaclasses, otherwise it is
244 not particularly useful.
254 =item B<meta_instance>
258 =item B<intialize_body>
260 =item B<associated_metaclass>
266 Stevan Little E<lt>stevan@iinteractive.comE<gt>
268 =head1 COPYRIGHT AND LICENSE
270 Copyright 2006, 2007 by Infinity Interactive, Inc.
272 L<http://www.iinteractive.com>
274 This library is free software; you can redistribute it and/or modify
275 it under the same terms as Perl itself.