2 package Moose::Meta::Attribute;
8 use Class::Load qw(is_class_loaded load_class);
9 use Scalar::Util 'blessed', 'weaken';
10 use List::MoreUtils 'any';
14 use Moose::Deprecated;
15 use Moose::Meta::Method::Accessor;
16 use Moose::Meta::Method::Delegation;
18 use Moose::Util::TypeConstraints ();
19 use Class::MOP::MiniTrait;
21 use base 'Class::MOP::Attribute', 'Moose::Meta::Mixin::AttributeCore';
23 Class::MOP::MiniTrait::apply(__PACKAGE__, 'Moose::Meta::Object::Trait');
25 __PACKAGE__->meta->add_attribute('traits' => (
26 reader => 'applied_traits',
27 predicate => 'has_applied_traits',
28 Class::MOP::_definition_context(),
31 # we need to have a ->does method in here to
32 # more easily support traits, and the introspection
33 # of those traits. We extend the does check to look
34 # for metatrait aliases.
36 my ($self, $role_name) = @_;
38 Moose::Util::resolve_metatrait_alias(Attribute => $role_name)
40 return 0 if !defined($name); # failed to load class
41 return $self->Moose::Object::does($name);
46 require Moose::Meta::Class;
47 ( ref $self && $self->associated_class ) || "Moose::Meta::Class";
52 my $inv = $self->_error_thrower;
53 unshift @_, "message" if @_ % 2 == 1;
54 unshift @_, attr => $self if ref $self;
56 my $handler = $inv->can("throw_error"); # to avoid incrementing depth by 1
60 sub _inline_throw_error {
61 my ( $self, $msg, $args ) = @_;
63 my $inv = $self->_error_thrower;
65 $inv = 'Moose::Meta::Class' unless $inv->can('_inline_throw_error');
68 my $class = $self->associated_class;
70 my $class_name = B::perlstring($class->name);
71 my $attr_name = B::perlstring($self->name);
72 $args = 'attr => Class::MOP::class_of(' . $class_name . ')'
73 . '->find_attribute_by_name(' . $attr_name . '), '
74 . (defined $args ? $args : '');
77 return $inv->_inline_throw_error($msg, $args)
81 my ($class, $name, %options) = @_;
82 $class->_process_options($name, \%options) unless $options{__hack_no_process_options}; # used from clone()... YECHKKK FIXME ICKY YUCK GROSS
84 delete $options{__hack_no_process_options};
89 map { $_->init_arg() }
90 $class->meta()->get_all_attributes()
93 my @bad = sort grep { ! $attrs{$_} } keys %options;
97 Carp::cluck "Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad";
100 return $class->SUPER::new($name, %options);
103 sub interpolate_class_and_new {
104 my ($class, $name, %args) = @_;
106 my ( $new_class, @traits ) = $class->interpolate_class(\%args);
108 $new_class->new($name, %args, ( scalar(@traits) ? ( traits => \@traits ) : () ) );
111 sub interpolate_class {
112 my ($class, $options) = @_;
114 $class = ref($class) || $class;
116 if ( my $metaclass_name = delete $options->{metaclass} ) {
117 my $new_class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name );
119 if ( $class ne $new_class ) {
120 if ( $new_class->can("interpolate_class") ) {
121 return $new_class->interpolate_class($options);
130 if (my $traits = $options->{traits}) {
132 my $has_foreign_options = 0;
134 while ($i < @$traits) {
135 my $trait = $traits->[$i++];
136 next if ref($trait); # options to a trait we discarded
138 $trait = Moose::Util::resolve_metatrait_alias(Attribute => $trait)
141 next if $class->does($trait);
143 push @traits, $trait;
146 if ($traits->[$i] && ref($traits->[$i])) {
147 $has_foreign_options = 1
148 if any { $_ ne '-alias' && $_ ne '-excludes' } keys %{ $traits->[$i] };
150 push @traits, $traits->[$i++];
156 superclasses => [ $class ],
157 roles => [ @traits ],
160 if ($has_foreign_options) {
161 $options{weaken} = 0;
167 my $anon_class = Moose::Meta::Class->create_anon_class(%options);
168 $class = $anon_class->name;
172 return ( wantarray ? ( $class, @traits ) : $class );
177 # method-generating options shouldn't be overridden
178 sub illegal_options_for_inheritance {
179 qw(reader writer accessor clearer predicate)
183 # This method *must* be able to handle
184 # Class::MOP::Attribute instances as
185 # well. Yes, I know that is wrong, but
186 # apparently we didn't realize it was
187 # doing that and now we have some code
188 # which is dependent on it. The real
189 # solution of course is to push this
190 # feature back up into Class::MOP::Attribute
191 # but I not right now, I am too lazy.
192 # However if you are reading this and
193 # looking for something to do,.. please
196 sub clone_and_inherit_options {
197 my ($self, %options) = @_;
200 # we may want to extends a Class::MOP::Attribute
201 # in which case we need to be able to use the
202 # core set of legal options that have always
203 # been here. But we allows Moose::Meta::Attribute
204 # instances to changes them.
206 my @illegal_options = $self->can('illegal_options_for_inheritance')
207 ? $self->illegal_options_for_inheritance
210 my @found_illegal_options = grep { exists $options{$_} && exists $self->{$_} ? $_ : undef } @illegal_options;
211 (scalar @found_illegal_options == 0)
212 || $self->throw_error("Illegal inherited options => (" . (join ', ' => @found_illegal_options) . ")", data => \%options);
216 if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) {
217 $type_constraint = $options{isa};
220 $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}, { package_defined_in => $options{definition_context}->{package} });
221 (defined $type_constraint)
222 || $self->throw_error("Could not find the type constraint '" . $options{isa} . "'", data => $options{isa});
225 $options{type_constraint} = $type_constraint;
228 if ($options{does}) {
230 if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) {
231 $type_constraint = $options{does};
234 $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}, { package_defined_in => $options{definition_context}->{package} });
235 (defined $type_constraint)
236 || $self->throw_error("Could not find the type constraint '" . $options{does} . "'", data => $options{does});
239 $options{type_constraint} = $type_constraint;
243 # this doesn't apply to Class::MOP::Attributes,
244 # so we can ignore it for them.
246 if ($self->can('interpolate_class')) {
247 ( $options{metaclass}, my @traits ) = $self->interpolate_class(\%options);
250 my @all_traits = grep { $seen{$_}++ } @{ $self->applied_traits || [] }, @traits;
251 $options{traits} = \@all_traits if @all_traits;
254 # This method can be called on a CMOP::Attribute object, so we need to
255 # make sure we can call this method.
256 $self->_process_lazy_build_option( $self->name, \%options )
257 if $self->can('_process_lazy_build_option');
259 $self->clone(%options);
263 my ( $self, %params ) = @_;
265 my $class = delete $params{metaclass} || ref $self;
267 my ( @init, @non_init );
269 foreach my $attr ( grep { $_->has_value($self) } Class::MOP::class_of($self)->get_all_attributes ) {
270 push @{ $attr->has_init_arg ? \@init : \@non_init }, $attr;
273 my %new_params = ( ( map { $_->init_arg => $_->get_value($self) } @init ), %params );
275 my $name = delete $new_params{name};
277 my $clone = $class->new($name, %new_params, __hack_no_process_options => 1 );
279 foreach my $attr ( @non_init ) {
280 $attr->set_value($clone, $attr->get_value($self));
286 sub _process_options {
287 my ( $class, $name, $options ) = @_;
289 $class->_process_is_option( $name, $options );
290 $class->_process_isa_option( $name, $options );
291 $class->_process_does_option( $name, $options );
292 $class->_process_coerce_option( $name, $options );
293 $class->_process_trigger_option( $name, $options );
294 $class->_process_auto_deref_option( $name, $options );
295 $class->_process_lazy_build_option( $name, $options );
296 $class->_process_lazy_option( $name, $options );
297 $class->_process_required_option( $name, $options );
300 sub _process_is_option {
301 my ( $class, $name, $options ) = @_;
303 return unless $options->{is};
305 ### -------------------------
306 ## is => ro, writer => _foo # turns into (reader => foo, writer => _foo) as before
307 ## is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
308 ## is => rw, accessor => _foo # turns into (accessor => _foo)
309 ## is => ro, accessor => _foo # error, accesor is rw
310 ### -------------------------
312 if ( $options->{is} eq 'ro' ) {
314 "Cannot define an accessor name on a read-only attribute, accessors are read/write",
316 if exists $options->{accessor};
317 $options->{reader} ||= $name;
319 elsif ( $options->{is} eq 'rw' ) {
320 if ( $options->{writer} ) {
321 $options->{reader} ||= $name;
324 $options->{accessor} ||= $name;
327 elsif ( $options->{is} eq 'bare' ) {
329 # do nothing, but don't complain (later) about missing methods
332 $class->throw_error( "I do not understand this option (is => "
334 . ") on attribute ($name)", data => $options->{is} );
338 sub _process_isa_option {
339 my ( $class, $name, $options ) = @_;
341 return unless exists $options->{isa};
343 if ( exists $options->{does} ) {
344 if ( try { $options->{isa}->can('does') } ) {
345 ( $options->{isa}->does( $options->{does} ) )
346 || $class->throw_error(
347 "Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)",
352 "Cannot have an isa option which cannot ->does() on attribute ($name)",
357 # allow for anon-subtypes here ...
358 if ( blessed( $options->{isa} )
359 && $options->{isa}->isa('Moose::Meta::TypeConstraint') ) {
360 $options->{type_constraint} = $options->{isa};
363 $options->{type_constraint}
364 = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint(
366 { package_defined_in => $options->{definition_context}->{package} }
371 sub _process_does_option {
372 my ( $class, $name, $options ) = @_;
374 return unless exists $options->{does} && ! exists $options->{isa};
376 # allow for anon-subtypes here ...
377 if ( blessed( $options->{does} )
378 && $options->{does}->isa('Moose::Meta::TypeConstraint') ) {
379 $options->{type_constraint} = $options->{does};
382 $options->{type_constraint}
383 = Moose::Util::TypeConstraints::find_or_create_does_type_constraint(
385 { package_defined_in => $options->{definition_context}->{package} }
390 sub _process_coerce_option {
391 my ( $class, $name, $options ) = @_;
393 return unless $options->{coerce};
395 ( exists $options->{type_constraint} )
396 || $class->throw_error(
397 "You cannot have coercion without specifying a type constraint on attribute ($name)",
401 "You cannot have a weak reference to a coerced value on attribute ($name)",
403 if $options->{weak_ref};
405 unless ( $options->{type_constraint}->has_coercion ) {
406 my $type = $options->{type_constraint}->name;
408 Moose::Deprecated::deprecated(
409 feature => 'coerce without coercion',
411 "You cannot coerce an attribute ($name) unless its type ($type) has a coercion"
416 sub _process_trigger_option {
417 my ( $class, $name, $options ) = @_;
419 return unless exists $options->{trigger};
421 ( 'CODE' eq ref $options->{trigger} )
422 || $class->throw_error("Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger});
425 sub _process_auto_deref_option {
426 my ( $class, $name, $options ) = @_;
428 return unless $options->{auto_deref};
430 ( exists $options->{type_constraint} )
431 || $class->throw_error(
432 "You cannot auto-dereference without specifying a type constraint on attribute ($name)",
435 ( $options->{type_constraint}->is_a_type_of('ArrayRef')
436 || $options->{type_constraint}->is_a_type_of('HashRef') )
437 || $class->throw_error(
438 "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)",
442 sub _process_lazy_build_option {
443 my ( $class, $name, $options ) = @_;
445 return unless $options->{lazy_build};
448 "You can not use lazy_build and default for the same attribute ($name)",
450 if exists $options->{default};
452 $options->{lazy} = 1;
453 $options->{builder} ||= "_build_${name}";
455 if ( $name =~ /^_/ ) {
456 $options->{clearer} ||= "_clear${name}";
457 $options->{predicate} ||= "_has${name}";
460 $options->{clearer} ||= "clear_${name}";
461 $options->{predicate} ||= "has_${name}";
465 sub _process_lazy_option {
466 my ( $class, $name, $options ) = @_;
468 return unless $options->{lazy};
470 ( exists $options->{default} || defined $options->{builder} )
471 || $class->throw_error(
472 "You cannot have a lazy attribute ($name) without specifying a default value for it",
476 sub _process_required_option {
477 my ( $class, $name, $options ) = @_;
482 ( !exists $options->{init_arg} || defined $options->{init_arg} )
483 || exists $options->{default}
484 || defined $options->{builder}
488 "You cannot have a required attribute ($name) without a default, builder, or an init_arg",
493 sub initialize_instance_slot {
494 my ($self, $meta_instance, $instance, $params) = @_;
495 my $init_arg = $self->init_arg();
496 # try to fetch the init arg from the %params ...
500 if ( defined($init_arg) and exists $params->{$init_arg}) {
501 $val = $params->{$init_arg};
505 # skip it if it's lazy
506 return if $self->is_lazy;
507 # and die if it's required and doesn't have a default value
508 $self->throw_error("Attribute (" . $self->name . ") is required", object => $instance, data => $params)
509 if $self->is_required && !$self->has_default && !$self->has_builder;
511 # if nothing was in the %params, we can use the
512 # attribute's default value (if it has one)
513 if ($self->has_default) {
514 $val = $self->default($instance);
517 elsif ($self->has_builder) {
518 $val = $self->_call_builder($instance);
523 return unless $value_is_set;
525 $val = $self->_coerce_and_verify( $val, $instance );
527 $self->set_initial_value($instance, $val);
529 if ( ref $val && $self->is_weak_ref ) {
530 $self->_weaken_value($instance);
535 my ( $self, $instance ) = @_;
537 my $builder = $self->builder();
539 return $instance->$builder()
540 if $instance->can( $self->builder );
542 $self->throw_error( blessed($instance)
543 . " does not support builder method '"
545 . "' for attribute '"
554 sub _make_initializer_writer_callback {
556 my ($meta_instance, $instance, $slot_name) = @_;
557 my $old_callback = $self->SUPER::_make_initializer_writer_callback(@_);
559 $old_callback->($self->_coerce_and_verify($_[0], $instance));
564 my ($self, $instance, @args) = @_;
565 my $value = $args[0];
567 my $attr_name = quotemeta($self->name);
569 if ($self->is_required and not @args) {
570 $self->throw_error("Attribute ($attr_name) is required", object => $instance);
573 $value = $self->_coerce_and_verify( $value, $instance );
576 if ( $self->has_trigger && $self->has_value($instance) ) {
577 @old = $self->get_value($instance, 'for trigger');
580 $self->SUPER::set_value($instance, $value);
582 if ( ref $value && $self->is_weak_ref ) {
583 $self->_weaken_value($instance);
586 if ($self->has_trigger) {
587 $self->trigger->($instance, $value, @old);
591 sub _inline_set_value {
593 my ($instance, $value, $tc, $coercion, $message, $for_constructor) = @_;
597 $tc ||= '$type_constraint';
598 $coercion ||= '$type_coercion';
599 $message ||= '$type_message';
602 if ($self->_writer_value_needs_copy) {
603 push @code, $self->_inline_copy_value($value, $copy);
607 # constructors already handle required checks
608 push @code, $self->_inline_check_required
609 unless $for_constructor;
611 push @code, $self->_inline_tc_code($value, $tc, $coercion, $message);
613 # constructors do triggers all at once at the end
614 push @code, $self->_inline_get_old_value_for_trigger($instance, $old)
615 unless $for_constructor;
618 $self->SUPER::_inline_set_value($instance, $value),
619 $self->_inline_weaken_value($instance, $value),
622 # constructors do triggers all at once at the end
623 push @code, $self->_inline_trigger($instance, $value, $old)
624 unless $for_constructor;
629 sub _writer_value_needs_copy {
631 return $self->should_coerce;
634 sub _inline_copy_value {
636 my ($value, $copy) = @_;
638 return 'my ' . $copy . ' = ' . $value . ';'
641 sub _inline_check_required {
644 return unless $self->is_required;
646 my $attr_name = quotemeta($self->name);
650 $self->_inline_throw_error(
651 '"Attribute (' . $attr_name . ') is required"'
657 sub _inline_tc_code {
659 my ($value, $tc, $coercion, $message, $is_lazy) = @_;
661 $self->_inline_check_coercion(
662 $value, $tc, $coercion, $is_lazy,
664 $self->_inline_check_constraint(
665 $value, $tc, $message, $is_lazy,
670 sub _inline_check_coercion {
672 my ($value, $tc, $coercion) = @_;
674 return unless $self->should_coerce && $self->type_constraint->has_coercion;
676 if ( $self->type_constraint->can_be_inlined ) {
678 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
679 $value . ' = ' . $coercion . '->(' . $value . ');',
685 'if (!' . $tc . '->(' . $value . ')) {',
686 $value . ' = ' . $coercion . '->(' . $value . ');',
692 sub _inline_check_constraint {
694 my ($value, $tc, $message) = @_;
696 return unless $self->has_type_constraint;
698 my $attr_name = quotemeta($self->name);
700 if ( $self->type_constraint->can_be_inlined ) {
702 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
703 $self->_inline_throw_error(
704 '"Attribute (' . $attr_name . ') does not pass the type '
705 . 'constraint because: " . '
706 . 'do { local $_ = ' . $value . '; '
707 . $message . '->(' . $value . ')'
716 'if (!' . $tc . '->(' . $value . ')) {',
717 $self->_inline_throw_error(
718 '"Attribute (' . $attr_name . ') does not pass the type '
719 . 'constraint because: " . '
720 . 'do { local $_ = ' . $value . '; '
721 . $message . '->(' . $value . ')'
730 sub _inline_get_old_value_for_trigger {
732 my ($instance, $old) = @_;
734 return unless $self->has_trigger;
737 'my ' . $old . ' = ' . $self->_inline_instance_has($instance),
738 '? ' . $self->_inline_instance_get($instance),
743 sub _inline_weaken_value {
745 my ($instance, $value) = @_;
747 return unless $self->is_weak_ref;
749 my $mi = $self->associated_class->get_meta_instance;
751 $mi->inline_weaken_slot_value($instance, $self->name),
752 'if ref ' . $value . ';',
756 sub _inline_trigger {
758 my ($instance, $value, $old) = @_;
760 return unless $self->has_trigger;
762 return '$trigger->(' . $instance . ', ' . $value . ', ' . $old . ');';
765 sub _eval_environment {
770 $env->{'$trigger'} = \($self->trigger)
771 if $self->has_trigger;
772 $env->{'$attr_default'} = \($self->default)
773 if $self->has_default;
775 if ($self->has_type_constraint) {
776 my $tc_obj = $self->type_constraint;
778 $env->{'$type_constraint'} = \(
779 $tc_obj->_compiled_type_constraint
780 ) unless $tc_obj->can_be_inlined;
781 # these two could probably get inlined versions too
782 $env->{'$type_coercion'} = \(
783 $tc_obj->coercion->_compiled_type_coercion
784 ) if $tc_obj->has_coercion;
785 $env->{'$type_message'} = \(
786 $tc_obj->has_message ? $tc_obj->message : $tc_obj->_default_message
789 $env = { %$env, %{ $tc_obj->inline_environment } };
793 $env->{'$attr'} = \$self
794 if $self->has_initializer && $self->is_lazy;
795 # pretty sure this is only going to be closed over if you use a custom
796 # error class at this point, but we should still get rid of this
798 $env->{'$meta'} = \($self->associated_class);
804 my ( $self, $instance ) = @_;
806 my $meta_instance = Class::MOP::Class->initialize( blessed($instance) )
809 $meta_instance->weaken_slot_value( $instance, $self->name );
813 my ($self, $instance, $for_trigger) = @_;
815 if ($self->is_lazy) {
816 unless ($self->has_value($instance)) {
818 if ($self->has_default) {
819 $value = $self->default($instance);
820 } elsif ( $self->has_builder ) {
821 $value = $self->_call_builder($instance);
824 $value = $self->_coerce_and_verify( $value, $instance );
826 $self->set_initial_value($instance, $value);
828 if ( ref $value && $self->is_weak_ref ) {
829 $self->_weaken_value($instance);
834 if ( $self->should_auto_deref && ! $for_trigger ) {
836 my $type_constraint = $self->type_constraint;
838 if ($type_constraint->is_a_type_of('ArrayRef')) {
839 my $rv = $self->SUPER::get_value($instance);
840 return unless defined $rv;
841 return wantarray ? @{ $rv } : $rv;
843 elsif ($type_constraint->is_a_type_of('HashRef')) {
844 my $rv = $self->SUPER::get_value($instance);
845 return unless defined $rv;
846 return wantarray ? %{ $rv } : $rv;
849 $self->throw_error("Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint);
855 return $self->SUPER::get_value($instance);
859 sub _inline_get_value {
861 my ($instance, $tc, $coercion, $message) = @_;
863 my $slot_access = $self->_inline_instance_get($instance);
864 $tc ||= '$type_constraint';
865 $coercion ||= '$type_coercion';
866 $message ||= '$type_message';
869 $self->_inline_check_lazy($instance, $tc, $coercion, $message),
870 $self->_inline_return_auto_deref($slot_access),
874 sub _inline_check_lazy {
876 my ($instance, $tc, $coercion, $message) = @_;
878 return unless $self->is_lazy;
880 my $slot_exists = $self->_inline_instance_has($instance);
883 'if (!' . $slot_exists . ') {',
884 $self->_inline_init_from_default($instance, '$default', $tc, $coercion, $message, 'lazy'),
889 sub _inline_init_from_default {
891 my ($instance, $default, $tc, $coercion, $message, $for_lazy) = @_;
893 if (!($self->has_default || $self->has_builder)) {
895 'You cannot have a lazy attribute '
896 . '(' . $self->name . ') '
897 . 'without specifying a default value for it',
903 $self->_inline_generate_default($instance, $default),
904 # intentionally not using _inline_tc_code, since that can be overridden
905 # to do things like possibly only do member tc checks, which isn't
906 # appropriate for checking the result of a default
907 $self->has_type_constraint
908 ? ($self->_inline_check_coercion($default, $tc, $coercion, $for_lazy),
909 $self->_inline_check_constraint($default, $tc, $message, $for_lazy))
911 $self->_inline_init_slot($instance, $default),
912 $self->_inline_weaken_value($instance, $default),
916 sub _inline_generate_default {
918 my ($instance, $default) = @_;
920 if ($self->has_default) {
921 my $source = 'my ' . $default . ' = $attr_default';
922 $source .= '->(' . $instance . ')'
923 if $self->is_default_a_coderef;
924 return $source . ';';
926 elsif ($self->has_builder) {
927 my $builder = B::perlstring($self->builder);
928 my $builder_str = quotemeta($self->builder);
929 my $attr_name_str = quotemeta($self->name);
931 'my ' . $default . ';',
932 'if (my $builder = ' . $instance . '->can(' . $builder . ')) {',
933 $default . ' = ' . $instance . '->$builder;',
936 'my $class = ref(' . $instance . ') || ' . $instance . ';',
937 $self->_inline_throw_error(
938 '"$class does not support builder method '
939 . '\'' . $builder_str . '\' for attribute '
940 . '\'' . $attr_name_str . '\'"'
947 "Can't generate a default for " . $self->name
948 . " since no default or builder was specified"
953 sub _inline_init_slot {
955 my ($inv, $value) = @_;
957 if ($self->has_initializer) {
958 return '$attr->set_initial_value(' . $inv . ', ' . $value . ');';
961 return $self->_inline_instance_set($inv, $value) . ';';
965 sub _inline_return_auto_deref {
968 return 'return ' . $self->_auto_deref(@_) . ';';
973 my ($ref_value) = @_;
975 return $ref_value unless $self->should_auto_deref;
977 my $type_constraint = $self->type_constraint;
980 if ($type_constraint->is_a_type_of('ArrayRef')) {
983 elsif ($type_constraint->is_a_type_of('HashRef')) {
988 'Can not auto de-reference the type constraint \''
989 . $type_constraint->name
991 type_constraint => $type_constraint,
996 . '? ' . $sigil . '{ (' . $ref_value . ') || return } '
997 . ': (' . $ref_value . ')';
1000 ## installing accessors
1002 sub accessor_metaclass { 'Moose::Meta::Method::Accessor' }
1004 sub install_accessors {
1006 $self->SUPER::install_accessors(@_);
1007 $self->install_delegation if $self->has_handles;
1011 sub _check_associated_methods {
1014 @{ $self->associated_methods }
1015 || ($self->_is_metadata || '') eq 'bare'
1018 'Attribute (' . $self->name . ') of class '
1019 . $self->associated_class->name
1020 . ' has no associated methods'
1021 . ' (did you mean to provide an "is" argument?)'
1027 sub _process_accessors {
1029 my ($type, $accessor, $generate_as_inline_methods) = @_;
1031 $accessor = ( keys %$accessor )[0] if ( ref($accessor) || '' ) eq 'HASH';
1032 my $method = $self->associated_class->get_method($accessor);
1035 && $method->isa('Class::MOP::Method::Accessor')
1036 && $method->associated_attribute->name ne $self->name ) {
1038 my $other_attr_name = $method->associated_attribute->name;
1039 my $name = $self->name;
1042 "You are overwriting an accessor ($accessor) for the $other_attr_name attribute"
1043 . " with a new accessor method for the $name attribute" );
1048 && !$method->is_stub
1049 && !$method->isa('Class::MOP::Method::Accessor')
1050 && ( !$self->definition_context
1051 || $method->package_name eq $self->definition_context->{package} )
1055 "You are overwriting a locally defined method ($accessor) with "
1059 if ( !$self->associated_class->has_method($accessor)
1060 && $self->associated_class->has_package_symbol( '&' . $accessor ) ) {
1063 "You are overwriting a locally defined function ($accessor) with "
1067 $self->SUPER::_process_accessors(@_);
1070 sub remove_accessors {
1072 $self->SUPER::remove_accessors(@_);
1073 $self->remove_delegation if $self->has_handles;
1077 sub install_delegation {
1081 # Here we canonicalize the 'handles' option
1082 # this will sort out any details and always
1083 # return an hash of methods which we want
1084 # to delagate to, see that method for details
1085 my %handles = $self->_canonicalize_handles;
1088 # install the delegation ...
1089 my $associated_class = $self->associated_class;
1090 foreach my $handle (sort keys %handles) {
1091 my $method_to_call = $handles{$handle};
1092 my $class_name = $associated_class->name;
1093 my $name = "${class_name}::${handle}";
1095 if ( my $method = $associated_class->get_method($handle) ) {
1097 "You cannot overwrite a locally defined method ($handle) with a delegation",
1098 method_name => $handle
1099 ) unless $method->is_stub;
1103 # handles is not allowed to delegate
1104 # any of these methods, as they will
1105 # override the ones in your class, which
1106 # is almost certainly not what you want.
1108 # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something
1109 #cluck("Not delegating method '$handle' because it is a core method") and
1110 next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle);
1112 my $method = $self->_make_delegation_method($handle, $method_to_call);
1114 $self->associated_class->add_method($method->name, $method);
1115 $self->associate_method($method);
1119 sub remove_delegation {
1121 my %handles = $self->_canonicalize_handles;
1122 my $associated_class = $self->associated_class;
1123 foreach my $handle (keys %handles) {
1124 next unless any { $handle eq $_ }
1126 @{ $self->associated_methods };
1127 $self->associated_class->remove_method($handle);
1131 # private methods to help delegation ...
1133 sub _canonicalize_handles {
1135 my $handles = $self->handles;
1136 if (my $handle_type = ref($handles)) {
1137 if ($handle_type eq 'HASH') {
1140 elsif ($handle_type eq 'ARRAY') {
1141 return map { $_ => $_ } @{$handles};
1143 elsif ($handle_type eq 'Regexp') {
1144 ($self->has_type_constraint)
1145 || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)", data => $handles);
1146 return map { ($_ => $_) }
1147 grep { /$handles/ } $self->_get_delegate_method_list;
1149 elsif ($handle_type eq 'CODE') {
1150 return $handles->($self, $self->_find_delegate_metaclass);
1152 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::DuckType')) {
1153 return map { $_ => $_ } @{ $handles->methods };
1155 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::Role')) {
1156 $handles = $handles->role;
1159 $self->throw_error("Unable to canonicalize the 'handles' option with $handles", data => $handles);
1163 load_class($handles);
1164 my $role_meta = Class::MOP::class_of($handles);
1166 (blessed $role_meta && $role_meta->isa('Moose::Meta::Role'))
1167 || $self->throw_error("Unable to canonicalize the 'handles' option with $handles because its metaclass is not a Moose::Meta::Role", data => $handles);
1169 return map { $_ => $_ }
1171 grep { !$_->isa('Class::MOP::Method::Meta') } (
1172 $role_meta->_get_local_methods,
1173 $role_meta->get_required_method_list,
1177 sub _get_delegate_method_list {
1179 my $meta = $self->_find_delegate_metaclass;
1180 if ($meta->isa('Class::MOP::Class')) {
1181 return map { $_->name } # NOTE: !never! delegate &meta
1182 grep { $_->package_name ne 'Moose::Object' && !$_->isa('Class::MOP::Method::Meta') }
1183 $meta->get_all_methods;
1185 elsif ($meta->isa('Moose::Meta::Role')) {
1186 return $meta->get_method_list;
1189 $self->throw_error("Unable to recognize the delegate metaclass '$meta'", data => $meta);
1193 sub _find_delegate_metaclass {
1195 if (my $class = $self->_isa_metadata) {
1196 unless ( is_class_loaded($class) ) {
1199 'The %s attribute is trying to delegate to a class which has not been loaded - %s',
1204 # we might be dealing with a non-Moose class,
1205 # and need to make our own metaclass. if there's
1206 # already a metaclass, it will be returned
1207 return Class::MOP::Class->initialize($class);
1209 elsif (my $role = $self->_does_metadata) {
1210 unless ( is_class_loaded($class) ) {
1213 'The %s attribute is trying to delegate to a role which has not been loaded - %s',
1219 return Class::MOP::class_of($role);
1222 $self->throw_error("Cannot find delegate metaclass for attribute " . $self->name);
1226 sub delegation_metaclass { 'Moose::Meta::Method::Delegation' }
1228 sub _make_delegation_method {
1229 my ( $self, $handle_name, $method_to_call ) = @_;
1231 my @curried_arguments;
1233 ($method_to_call, @curried_arguments) = @$method_to_call
1234 if 'ARRAY' eq ref($method_to_call);
1236 return $self->delegation_metaclass->new(
1237 name => $handle_name,
1238 package_name => $self->associated_class->name,
1240 delegate_to_method => $method_to_call,
1241 curried_arguments => \@curried_arguments,
1245 sub _coerce_and_verify {
1248 my $instance = shift;
1250 return $val unless $self->has_type_constraint;
1252 $val = $self->type_constraint->coerce($val)
1253 if $self->should_coerce && $self->type_constraint->has_coercion;
1255 $self->verify_against_type_constraint($val, instance => $instance);
1260 sub verify_against_type_constraint {
1264 return 1 if !$self->has_type_constraint;
1266 my $type_constraint = $self->type_constraint;
1268 $type_constraint->check($val)
1269 || $self->throw_error("Attribute ("
1271 . ") does not pass the type constraint because: "
1272 . $type_constraint->get_message($val), data => $val, @_);
1275 package Moose::Meta::Attribute::Custom::Moose;
1276 sub register_implementation { 'Moose::Meta::Attribute' }
1280 # ABSTRACT: The Moose attribute metaclass
1288 This class is a subclass of L<Class::MOP::Attribute> that provides
1289 additional Moose-specific functionality.
1291 To really understand this class, you will need to start with the
1292 L<Class::MOP::Attribute> documentation. This class can be understood
1293 as a set of additional features on top of the basic feature provided
1294 by that parent class.
1298 C<Moose::Meta::Attribute> is a subclass of L<Class::MOP::Attribute>.
1302 Many of the documented below override methods in
1303 L<Class::MOP::Attribute> and add Moose specific features.
1309 =item B<< Moose::Meta::Attribute->new($name, %options) >>
1311 This method overrides the L<Class::MOP::Attribute> constructor.
1313 Many of the options below are described in more detail in the
1314 L<Moose::Manual::Attributes> document.
1316 It adds the following options to the constructor:
1320 =item * is => 'ro', 'rw', 'bare'
1322 This provides a shorthand for specifying the C<reader>, C<writer>, or
1323 C<accessor> names. If the attribute is read-only ('ro') then it will
1324 have a C<reader> method with the same attribute as the name.
1326 If it is read-write ('rw') then it will have an C<accessor> method
1327 with the same name. If you provide an explicit C<writer> for a
1328 read-write attribute, then you will have a C<reader> with the same
1329 name as the attribute, and a C<writer> with the name you provided.
1331 Use 'bare' when you are deliberately not installing any methods
1332 (accessor, reader, etc.) associated with this attribute; otherwise,
1333 Moose will issue a deprecation warning when this attribute is added to a
1336 =item * isa => $type
1338 This option accepts a type. The type can be a string, which should be
1339 a type name. If the type name is unknown, it is assumed to be a class
1342 This option can also accept a L<Moose::Meta::TypeConstraint> object.
1344 If you I<also> provide a C<does> option, then your C<isa> option must
1345 be a class name, and that class must do the role specified with
1348 =item * does => $role
1350 This is short-hand for saying that the attribute's type must be an
1351 object which does the named role.
1353 =item * coerce => $bool
1355 This option is only valid for objects with a type constraint
1356 (C<isa>) that defined a coercion. If this is true, then coercions will be applied whenever
1357 this attribute is set.
1359 You can make both this and the C<weak_ref> option true.
1361 =item * trigger => $sub
1363 This option accepts a subroutine reference, which will be called after
1364 the attribute is set.
1366 =item * required => $bool
1368 An attribute which is required must be provided to the constructor. An
1369 attribute which is required can also have a C<default> or C<builder>,
1370 which will satisfy its required-ness.
1372 A required attribute must have a C<default>, C<builder> or a
1373 non-C<undef> C<init_arg>
1375 =item * lazy => $bool
1377 A lazy attribute must have a C<default> or C<builder>. When an
1378 attribute is lazy, the default value will not be calculated until the
1381 =item * weak_ref => $bool
1383 If this is true, the attribute's value will be stored as a weak
1386 =item * auto_deref => $bool
1388 If this is true, then the reader will dereference the value when it is
1389 called. The attribute must have a type constraint which defines the
1390 attribute as an array or hash reference.
1392 =item * lazy_build => $bool
1394 Setting this to true makes the attribute lazy and provides a number of
1402 is equivalent to this:
1407 builder => '_build_size',
1408 clearer => 'clear_size',
1409 predicate => 'has_size',
1413 If your attribute name starts with an underscore (C<_>), then the clearer
1414 and predicate will as well:
1426 builder => '_build__size',
1427 clearer => '_clear_size',
1428 predicate => '_has_size',
1431 Note the doubled underscore in the builder name. Internally, Moose
1432 simply prepends the attribute name with "_build_" to come up with the
1435 =item * documentation
1437 An arbitrary string that can be retrieved later by calling C<<
1438 $attr->documentation >>.
1442 =item B<< $attr->clone(%options) >>
1444 This creates a new attribute based on attribute being cloned. You must
1445 supply a C<name> option to provide a new name for the attribute.
1447 The C<%options> can only specify options handled by
1448 L<Class::MOP::Attribute>.
1452 =head2 Value management
1456 =item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >>
1458 This method is used internally to initialize the attribute's slot in
1459 the object C<$instance>.
1461 This overrides the L<Class::MOP::Attribute> method to handle lazy
1462 attributes, weak references, and type constraints.
1468 eval { $point->meta->get_attribute('x')->set_value($point, 'forty-two') };
1473 I<Attribute (x) does not pass the type constraint (Int) with 'forty-two'>
1475 Before setting the value, a check is made on the type constraint of
1476 the attribute, if it has one, to see if the value passes it. If the
1477 value fails to pass, the set operation dies.
1479 Any coercion to convert values is done before checking the type constraint.
1481 To check a value against a type constraint before setting it, fetch the
1482 attribute instance using L<Class::MOP::Class/find_attribute_by_name>,
1483 fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint>
1484 and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Company_Subtypes>
1489 =head2 Attribute Accessor generation
1493 =item B<< $attr->install_accessors >>
1495 This method overrides the parent to also install delegation methods.
1497 If, after installing all methods, the attribute object has no associated
1498 methods, it throws an error unless C<< is => 'bare' >> was passed to the
1499 attribute constructor. (Trying to add an attribute that has no associated
1500 methods is almost always an error.)
1502 =item B<< $attr->remove_accessors >>
1504 This method overrides the parent to also remove delegation methods.
1506 =item B<< $attr->inline_set($instance_var, $value_var) >>
1508 This method return a code snippet suitable for inlining the relevant
1509 operation. It expect strings containing variable names to be used in the
1510 inlining, like C<'$self'> or C<'$_[1]'>.
1512 =item B<< $attr->install_delegation >>
1514 This method adds its delegation methods to the attribute's associated
1515 class, if it has any to add.
1517 =item B<< $attr->remove_delegation >>
1519 This method remove its delegation methods from the attribute's
1522 =item B<< $attr->accessor_metaclass >>
1524 Returns the accessor metaclass name, which defaults to
1525 L<Moose::Meta::Method::Accessor>.
1527 =item B<< $attr->delegation_metaclass >>
1529 Returns the delegation metaclass name, which defaults to
1530 L<Moose::Meta::Method::Delegation>.
1534 =head2 Additional Moose features
1536 These methods are not found in the superclass. They support features
1541 =item B<< $attr->does($role) >>
1543 This indicates whether the I<attribute itself> does the given
1544 role. The role can be given as a full class name, or as a resolvable
1547 Note that this checks the attribute itself, not its type constraint,
1548 so it is checking the attribute's metaclass and any traits applied to
1551 =item B<< Moose::Meta::Class->interpolate_class_and_new($name, %options) >>
1553 This is an alternate constructor that handles the C<metaclass> and
1556 Effectively, this method is a factory that finds or creates the
1557 appropriate class for the given C<metaclass> and/or C<traits>.
1559 Once it has the appropriate class, it will call C<< $class->new($name,
1560 %options) >> on that class.
1562 =item B<< $attr->clone_and_inherit_options(%options) >>
1564 This method supports the C<has '+foo'> feature. It does various bits
1565 of processing on the supplied C<%options> before ultimately calling
1566 the C<clone> method.
1568 One of its main tasks is to make sure that the C<%options> provided
1569 does not include the options returned by the
1570 C<illegal_options_for_inheritance> method.
1572 =item B<< $attr->illegal_options_for_inheritance >>
1574 This returns a blacklist of options that can not be overridden in a
1575 subclass's attribute definition.
1577 This exists to allow a custom metaclass to change or add to the list
1578 of options which can not be changed.
1580 =item B<< $attr->type_constraint >>
1582 Returns the L<Moose::Meta::TypeConstraint> object for this attribute,
1585 =item B<< $attr->has_type_constraint >>
1587 Returns true if this attribute has a type constraint.
1589 =item B<< $attr->verify_against_type_constraint($value) >>
1591 Given a value, this method returns true if the value is valid for the
1592 attribute's type constraint. If the value is not valid, it throws an
1595 =item B<< $attr->handles >>
1597 This returns the value of the C<handles> option passed to the
1600 =item B<< $attr->has_handles >>
1602 Returns true if this attribute performs delegation.
1604 =item B<< $attr->is_weak_ref >>
1606 Returns true if this attribute stores its value as a weak reference.
1608 =item B<< $attr->is_required >>
1610 Returns true if this attribute is required to have a value.
1612 =item B<< $attr->is_lazy >>
1614 Returns true if this attribute is lazy.
1616 =item B<< $attr->is_lazy_build >>
1618 Returns true if the C<lazy_build> option was true when passed to the
1621 =item B<< $attr->should_coerce >>
1623 Returns true if the C<coerce> option passed to the constructor was
1626 =item B<< $attr->should_auto_deref >>
1628 Returns true if the C<auto_deref> option passed to the constructor was
1631 =item B<< $attr->trigger >>
1633 This is the subroutine reference that was in the C<trigger> option
1634 passed to the constructor, if any.
1636 =item B<< $attr->has_trigger >>
1638 Returns true if this attribute has a trigger set.
1640 =item B<< $attr->documentation >>
1642 Returns the value that was in the C<documentation> option passed to
1643 the constructor, if any.
1645 =item B<< $attr->has_documentation >>
1647 Returns true if this attribute has any documentation.
1649 =item B<< $attr->applied_traits >>
1651 This returns an array reference of all the traits which were applied
1652 to this attribute. If none were applied, this returns C<undef>.
1654 =item B<< $attr->has_applied_traits >>
1656 Returns true if this attribute has any traits applied.
1662 See L<Moose/BUGS> for details on reporting bugs.