package Moose::Meta::Method::Constructor;
use strict;
use warnings;
use Carp 'confess';
use Scalar::Util 'blessed', 'weaken', 'looks_like_number';
our $VERSION = '0.05';
our $AUTHORITY = 'cpan:STEVAN';
use base 'Moose::Meta::Method',
'Class::MOP::Method::Generated';
sub new {
my $class = shift;
my %options = @_;
(exists $options{options} && ref $options{options} eq 'HASH')
|| confess "You must pass a hash of options";
my $self = bless {
# from our superclass
'&!body' => undef,
# specific to this subclass
'%!options' => $options{options},
'$!meta_instance' => $options{metaclass}->get_meta_instance,
'@!attributes' => [ $options{metaclass}->compute_all_applicable_attributes ],
# ...
'$!associated_metaclass' => $options{metaclass},
} => $class;
# we don't want this creating
# a cycle in the code, if not
# needed
weaken($self->{'$!associated_metaclass'});
$self->intialize_body;
return $self;
}
## accessors
sub options { (shift)->{'%!options'} }
sub meta_instance { (shift)->{'$!meta_instance'} }
sub attributes { (shift)->{'@!attributes'} }
sub associated_metaclass { (shift)->{'$!associated_metaclass'} }
## method
sub intialize_body {
my $self = shift;
# TODO:
# the %options should also include a both
# a call 'initializer' and call 'SUPER::'
# options, which should cover approx 90%
# of the possible use cases (even if it
# requires some adaption on the part of
# the author, after all, nothing is free)
my $source = 'sub {';
$source .= "\n" . 'my $class = shift;';
$source .= "\n" . 'return $class->Moose::Object::new(@_)';
$source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';';
$source .= "\n" . 'my %params = (scalar @_ == 1) ? %{$_[0]} : @_;';
$source .= "\n" . 'my $instance = ' . $self->meta_instance->inline_create_instance('$class');
$source .= ";\n" . (join ";\n" => map {
$self->_generate_slot_initializer($_)
} 0 .. (@{$self->attributes} - 1));
$source .= ";\n" . $self->_generate_BUILDALL();
$source .= ";\n" . 'return $instance';
$source .= ";\n" . '}';
warn $source if $self->options->{debug};
my $code;
{
# NOTE:
# create the nessecary lexicals
# to be picked up in the eval
my $attrs = $self->attributes;
my @type_constraints = map { $_->type_constraint } @$attrs;
my @type_constraint_bodies = map {
$_ && $_->_compiled_type_constraint;
} @type_constraints;
$code = eval $source;
confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@;
}
$self->{'&!body'} = $code;
}
sub _generate_BUILDALL {
my $self = shift;
my @BUILD_calls;
foreach my $method (reverse $self->associated_metaclass->find_all_methods_by_name('BUILD')) {
push @BUILD_calls => '$instance->' . $method->{class} . '::BUILD(\%params)';
}
return join ";\n" => @BUILD_calls;
}
sub _generate_slot_initializer {
my $self = shift;
my $index = shift;
my $attr = $self->attributes->[$index];
my @source = ('## ' . $attr->name);
my $is_moose = $attr->isa('Moose::Meta::Attribute'); # XXX FIXME
if ($is_moose && $attr->is_required && !$attr->has_default && !$attr->has_builder) {
push @source => ('(exists $params{\'' . $attr->init_arg . '\'}) ' .
'|| confess "Attribute (' . $attr->name . ') is required";');
}
if (($attr->has_default || $attr->has_builder) && !($is_moose && $attr->is_lazy)) {
push @source => 'if (exists $params{\'' . $attr->init_arg . '\'}) {';
push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
if ($is_moose && $attr->has_type_constraint) {
if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
push @source => $self->_generate_type_coercion($attr, '$type_constraints[' . $index . ']', '$val', '$val');
}
push @source => $self->_generate_type_constraint_check($attr, '$type_constraint_bodies[' . $index . ']', '$val');
}
push @source => $self->_generate_slot_assignment($attr, '$val');
push @source => "} else {";
my $default;
if ( $attr->has_default ) {
$default = $self->_generate_default_value($attr, $index);
}
else {
my $builder = $attr->builder;
$default = '$instance->' . $builder;
}
push @source => ('my $val = ' . $default . ';');
push @source => $self->_generate_type_constraint_check(
$attr,
('$type_constraint_bodies[' . $index . ']'),
'$val'
) if ($is_moose && $attr->has_type_constraint);
push @source => $self->_generate_slot_assignment($attr, $default);
push @source => "}";
}
else {
push @source => '(exists $params{\'' . $attr->init_arg . '\'}) && do {';
push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
if ($is_moose && $attr->has_type_constraint) {
if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
push @source => $self->_generate_type_coercion($attr, '$type_constraints[' . $index . ']', '$val', '$val');
}
push @source => $self->_generate_type_constraint_check($attr, '$type_constraint_bodies[' . $index . ']', '$val');
}
push @source => $self->_generate_slot_assignment($attr, '$val');
push @source => "}";
}
return join "\n" => @source;
}
sub _generate_slot_assignment {
my ($self, $attr, $value) = @_;
my $source = (
$self->meta_instance->inline_set_slot_value(
'$instance',
("'" . $attr->name . "'"),
$value
) . ';'
);
my $is_moose = $attr->isa('Moose::Meta::Attribute'); # XXX FIXME
if ($is_moose && $attr->is_weak_ref) {
$source .= (
"\n" .
$self->meta_instance->inline_weaken_slot_value(
'$instance',
("'" . $attr->name . "'")
) .
' if ref ' . $value . ';'
);
}
return $source;
}
sub _generate_type_coercion {
my ($self, $attr, $type_constraint_name, $value_name, $return_value_name) = @_;
return ($return_value_name . ' = ' . $type_constraint_name . '->coerce(' . $value_name . ');');
}
sub _generate_type_constraint_check {
my ($self, $attr, $type_constraint_cv, $value_name) = @_;
return (
$type_constraint_cv . '->(' . $value_name . ')'
. "\n\t" . '|| confess "Attribute (' . $attr->name . ') does not pass the type constraint ('
. $attr->type_constraint->name
. ') with " . (defined(' . $value_name . ') ? overload::StrVal(' . $value_name . ') : "undef");'
);
}
sub _generate_default_value {
my ($self, $attr, $index) = @_;
# NOTE:
# default values can either be CODE refs
# in which case we need to call them. Or
# they can be scalars (strings/numbers)
# in which case we can just deal with them
# in the code we eval.
if ($attr->is_default_a_coderef) {
return '$attrs->[' . $index . ']->default($instance)';
}
else {
my $default = $attr->default;
# make sure to quote strings ...
unless (looks_like_number($default)) {
$default = "'$default'";
}
return $default;
}
}
1;
__END__
=pod
=head1 NAME
Moose::Meta::Method::Constructor - Method Meta Object for constructors
=head1 DESCRIPTION
This is a subclass of L<Class::MOP::Method> which handles
constructing an approprate Constructor methods. This is primarily
used in the making of immutable metaclasses, otherwise it is
not particularly useful.
=head1 METHODS
=over 4
=item B<new>
=item B<attributes>
=item B<meta_instance>
=item B<options>
=item B<intialize_body>
=item B<associated_metaclass>
=back
=head1 AUTHORS
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2006-2008 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut