[gitmo/Moose.git] / lib / Moose / Meta / Method / Constructor.pm


package Moose::Meta::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 'Moose::Meta::Method';

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;
        
        $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);
    
    if ($attr->is_required && !$attr->has_default) {
        push @source => ('(exists $params{\'' . $attr->init_arg . '\'}) ' . 
                        '|| confess "Attribute (' . $attr->name . ') is required";');
    }
    
    if ($attr->has_default && !$attr->is_lazy) {
        
        push @source => 'if (exists $params{\'' . $attr->init_arg . '\'}) {';

            push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
            if ($attr->has_type_constraint) {
                push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');

                if ($attr->should_coerce && $attr->type_constraint->has_coercion) {                    
                    push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');        
                }
                push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$val');        
            }
            push @source => $self->_generate_slot_assignment($attr, '$val');        
        
        
        push @source => "} else {";            
        
            my $default = $self->_generate_default_value($attr, $index);  
        
            push @source => ('my $val = ' . $default . ';');
            push @source => $self->_generate_type_constraint_check(
                $attr,
                ('$attrs->[' . $index . ']->type_constraint'), 
                '$val'
            ) if $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{\'' . $attr->init_arg . '\'};');
            if ($attr->has_type_constraint) {
                push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');

                if ($attr->should_coerce && $attr->type_constraint->has_coercion) {                    
                    push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');        
                }
                push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$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
        ) . ';'
    ); 
    
    if ($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_name, $value_name) = @_;
    return (
        'defined(' . $type_constraint_name . '->_compiled_type_constraint->(' . $value_name . '))'
    	. "\n\t" . '|| confess "Attribute (' . $attr->name . ') does not pass the type constraint ('
        . $attr->type_constraint->name . ') with " . (defined() ? "' . $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;

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, 2007 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
Commit	Line	Data
5cf3dbcf	1
	2	package Moose::Meta::Method::Constructor;
	3
	4	use strict;
	5	use warnings;
	6
	7	use Carp 'confess';
	8	use Scalar::Util 'blessed', 'weaken', 'looks_like_number';
	9
	10	our $VERSION = '0.01';
	11	our $AUTHORITY = 'cpan:STEVAN';
	12
	13	use base 'Moose::Meta::Method';
	14
	15	sub new {
	16	my $class = shift;
	17	my %options = @_;
	18
	19	(exists $options{options} && ref $options{options} eq 'HASH')
	20	\|\| confess "You must pass a hash of options";
5cf3dbcf	21
	22	my $self = bless {
	23	# from our superclass
	24	'&!body' => undef,
	25	# specific to this subclass
	26	'%!options' => $options{options},
587ae0d2	27	'$!meta_instance' => $options{metaclass}->get_meta_instance,
587ae0d2	28	'@!attributes' => [ $options{metaclass}->compute_all_applicable_attributes ],
5cf3dbcf	29	# ...
	30	'$!associated_metaclass' => $options{metaclass},
	31	} => $class;
	32
	33	# we don't want this creating
	34	# a cycle in the code, if not
	35	# needed
5cf3dbcf	36	weaken($self->{'$!associated_metaclass'});
	37
	38	$self->intialize_body;
	39
	40	return $self;
	41	}
	42
	43	## accessors
	44
	45	sub options { (shift)->{'%!options'} }
	46	sub meta_instance { (shift)->{'$!meta_instance'} }
	47	sub attributes { (shift)->{'@!attributes'} }
	48
	49	sub associated_metaclass { (shift)->{'$!associated_metaclass'} }
	50
	51	## method
	52
	53	sub intialize_body {
	54	my $self = shift;
	55	# TODO:
	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)
	62	my $source = 'sub {';
1f779926	63	$source .= "\n" . 'my $class = shift;';
1f779926	64
587ae0d2	65	$source .= "\n" . 'return $class->Moose::Object::new(@_)';
1f779926	66	$source .= "\n" . ' if $class ne \'' . $self->associated_metaclass->name . '\';';
1f779926	67
5cf3dbcf	68	$source .= "\n" . 'my %params = (scalar @_ == 1) ? %{$_[0]} : @_;';
	69
	70	$source .= "\n" . 'my $instance = ' . $self->meta_instance->inline_create_instance('$class');
	71
	72	$source .= ";\n" . (join ";\n" => map {
	73	$self->_generate_slot_initializer($_)
	74	} 0 .. (@{$self->attributes} - 1));
	75
	76	$source .= ";\n" . $self->_generate_BUILDALL();
	77
	78	$source .= ";\n" . 'return $instance';
	79	$source .= ";\n" . '}';
	80	warn $source if $self->options->{debug};
	81
	82	my $code;
	83	{
	84	# NOTE:
	85	# create the nessecary lexicals
	86	# to be picked up in the eval
	87	my $attrs = $self->attributes;
	88
	89	$code = eval $source;
	90	confess "Could not eval the constructor :\n\n$source\n\nbecause :\n\n$@" if $@;
	91	}
	92	$self->{'&!body'} = $code;
	93	}
	94
	95	sub _generate_BUILDALL {
	96	my $self = shift;
	97	my @BUILD_calls;
1f779926	98	foreach my $method (reverse $self->associated_metaclass->find_all_methods_by_name('BUILD')) {
8ecb1fa0	99	push @BUILD_calls => '$instance->' . $method->{class} . '::BUILD(\%params)';
5cf3dbcf	100	}
	101	return join "\n" => @BUILD_calls;
	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 @source = ('## ' . $attr->name);
	111
	112	if ($attr->is_required && !$attr->has_default) {
	113	push @source => ('(exists $params{\'' . $attr->init_arg . '\'}) ' .
	114	'\|\| confess "Attribute (' . $attr->name . ') is required";');
	115	}
	116
5cf3dbcf	117	if ($attr->has_default && !$attr->is_lazy) {
5cf3dbcf	118
8ecb1fa0	119	push @source => 'if (exists $params{\'' . $attr->init_arg . '\'}) {';
	120
	121	push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
	122	if ($attr->has_type_constraint) {
	123	push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');
	124
	125	if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
	126	push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');
	127	}
	128	push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$val');
	129	}
	130	push @source => $self->_generate_slot_assignment($attr, '$val');
	131
	132
5cf3dbcf	133	push @source => "} else {";
	134
	135	my $default = $self->_generate_default_value($attr, $index);
	136
	137	push @source => ('my $val = ' . $default . ';');
	138	push @source => $self->_generate_type_constraint_check(
	139	$attr,
	140	('$attrs->[' . $index . ']->type_constraint'),
	141	'$val'
	142	) if $attr->has_type_constraint;
	143	push @source => $self->_generate_slot_assignment($attr, $default);
	144
	145	push @source => "}";
	146	}
	147	else {
8ecb1fa0	148	push @source => '(exists $params{\'' . $attr->init_arg . '\'}) && do {';
	149
	150	push @source => ('my $val = $params{\'' . $attr->init_arg . '\'};');
	151	if ($attr->has_type_constraint) {
	152	push @source => ('my $type_constraint = $attrs->[' . $index . ']->type_constraint;');
	153
	154	if ($attr->should_coerce && $attr->type_constraint->has_coercion) {
	155	push @source => $self->_generate_type_coercion($attr, '$type_constraint', '$val', '$val');
	156	}
	157	push @source => $self->_generate_type_constraint_check($attr, '$type_constraint', '$val');
	158	}
	159	push @source => $self->_generate_slot_assignment($attr, '$val');
	160
5cf3dbcf	161	push @source => "}";
	162	}
	163
	164	return join "\n" => @source;
	165	}
	166
	167	sub _generate_slot_assignment {
	168	my ($self, $attr, $value) = @_;
	169	my $source = (
	170	$self->meta_instance->inline_set_slot_value(
	171	'$instance',
	172	("'" . $attr->name . "'"),
	173	$value
	174	) . ';'
	175	);
	176
	177	if ($attr->is_weak_ref) {
	178	$source .= (
	179	"\n" .
	180	$self->meta_instance->inline_weaken_slot_value(
	181	'$instance',
	182	("'" . $attr->name . "'")
	183	) .
	184	' if ref ' . $value . ';'
	185	);
	186	}
	187
	188	return $source;
	189	}
	190
	191	sub _generate_type_coercion {
	192	my ($self, $attr, $type_constraint_name, $value_name, $return_value_name) = @_;
	193	return ($return_value_name . ' = ' . $type_constraint_name . '->coerce(' . $value_name . ');');
	194	}
	195
	196	sub _generate_type_constraint_check {
	197	my ($self, $attr, $type_constraint_name, $value_name) = @_;
	198	return (
	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() ? "' . $value_name . '" : "undef");'
	202	);
	203	}
	204
	205	sub _generate_default_value {
	206	my ($self, $attr, $index) = @_;
	207	# NOTE:
	208	# default values can either be CODE refs
	209	# in which case we need to call them. Or
	210	# they can be scalars (strings/numbers)
	211	# in which case we can just deal with them
	212	# in the code we eval.
	213	if ($attr->is_default_a_coderef) {
	214	return '$attrs->[' . $index . ']->default($instance)';
	215	}
	216	else {
	217	my $default = $attr->default;
	218	# make sure to quote strings ...
	219	unless (looks_like_number($default)) {
	220	$default = "'$default'";
	221	}
	222
	223	return $default;
	224	}
225	}
226
227	1;
228
229	1;
230
231	__END__
232
233	=pod
234
235	=head1 NAME
236
237	Moose::Meta::Method::Constructor - Method Meta Object for constructors
238
5cf3dbcf	239	=head1 DESCRIPTION
5cf3dbcf	240
d44714be	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.
	245
5cf3dbcf	246	=head1 METHODS
	247
	248	=over 4
	249
	250	=item B<new>
	251
	252	=item B<attributes>
	253
	254	=item B<meta_instance>
	255
	256	=item B<options>
	257
	258	=item B<intialize_body>
	259
	260	=item B<associated_metaclass>
	261
	262	=back
	263
	264	=head1 AUTHORS
	265
	266	Stevan Little E<lt>stevan@iinteractive.comE<gt>
	267
	268	=head1 COPYRIGHT AND LICENSE
	269
b77fdbed	270	Copyright 2006, 2007 by Infinity Interactive, Inc.
5cf3dbcf	271
	272	L<http://www.iinteractive.com>
	273
	274	This library is free software; you can redistribute it and/or modify
	275	it under the same terms as Perl itself.
	276
	277	=cut
	278