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|
package Class::MOP::Method::Constructor;
use strict;
use warnings;
use Carp 'confess';
use Scalar::Util 'blessed', 'weaken', 'looks_like_number';
our $VERSION = '0.01';
our $AUTHORITY = 'cpan:STEVAN';
use base 'Class::MOP::Method';
sub new {
my $class = shift;
my %options = @_;
(exists $options{options} && ref $options{options} eq 'HASH')
|| confess "You must pass a hash of options";
(blessed $options{meta_instance} && $options{meta_instance}->isa('Class::MOP::Instance'))
|| confess "You must supply a meta-instance";
(exists $options{attributes} && ref $options{attributes} eq 'ARRAY')
|| confess "You must pass an array of options";
(blessed($_) && $_->isa('Class::MOP::Attribute'))
|| confess "You must supply a list of attributes which is a 'Class::MOP::Attribute' instance"
for @{$options{attributes}};
my $self = bless {
# from our superclass
body => undef,
# specific to this subclass
options => $options{options},
meta_instance => $options{meta_instance},
attributes => $options{attributes},
} => $class;
# we don't want this creating
# a cycle in the code, if not
# needed
weaken($self->{meta_instance});
$self->intialize_body;
return $self;
}
## accessors
sub options { (shift)->{options} }
sub meta_instance { (shift)->{meta_instance} }
sub attributes { (shift)->{attributes} }
## 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, %params) = @_;';
$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" . '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;
$code = eval $source;
confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@;
}
$self->{body} = $code;
}
sub _generate_slot_initializer {
my $self = shift;
my $index = shift;
my $attr = $self->attributes->[$index];
my $default;
if ($attr->has_default) {
# 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) {
$default = '$attrs->[' . $index . ']->default($instance)';
}
else {
$default = $attr->default;
# make sure to quote strings ...
unless (looks_like_number($default)) {
$default = "'$default'";
}
}
}
$self->meta_instance->inline_set_slot_value(
'$instance',
("'" . $attr->name . "'"),
('$params{\'' . $attr->init_arg . '\'}' . (defined $default ? (' || ' . $default) : ''))
);
}
1;
1;
__END__
=pod
=head1 NAME
Class::MOP::Method::Constructor - Method Meta Object for constructors
=head1 SYNOPSIS
=head1 DESCRIPTION
=head1 METHODS
=over 4
=item B<new>
=item B<attributes>
=item B<meta_instance>
=item B<options>
=item B<intialize_body>
=back
=head1 AUTHORS
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2006 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
|
