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 Moose::Util::throw(@_);
55 sub _inline_throw_error {
56 my ( $self, $msg, $args ) = @_;
58 my $inv = $self->_error_thrower;
60 $inv = 'Moose::Meta::Class' unless $inv->can('_inline_throw_error');
62 return $inv->_inline_throw_error($msg, $args)
66 my ($class, $name, %options) = @_;
67 $class->_process_options($name, \%options) unless $options{__hack_no_process_options}; # used from clone()... YECHKKK FIXME ICKY YUCK GROSS
69 delete $options{__hack_no_process_options};
74 map { $_->init_arg() }
75 $class->meta()->get_all_attributes()
78 my @bad = sort grep { ! $attrs{$_} } keys %options;
82 Carp::cluck "Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad";
85 return $class->SUPER::new($name, %options);
88 sub interpolate_class_and_new {
89 my ($class, $name, %args) = @_;
91 my ( $new_class, @traits ) = $class->interpolate_class(\%args);
93 $new_class->new($name, %args, ( scalar(@traits) ? ( traits => \@traits ) : () ) );
96 sub interpolate_class {
97 my ($class, $options) = @_;
99 $class = ref($class) || $class;
101 if ( my $metaclass_name = delete $options->{metaclass} ) {
102 my $new_class = Moose::Util::resolve_metaclass_alias( Attribute => $metaclass_name );
104 if ( $class ne $new_class ) {
105 if ( $new_class->can("interpolate_class") ) {
106 return $new_class->interpolate_class($options);
115 if (my $traits = $options->{traits}) {
117 my $has_foreign_options = 0;
119 while ($i < @$traits) {
120 my $trait = $traits->[$i++];
121 next if ref($trait); # options to a trait we discarded
123 $trait = Moose::Util::resolve_metatrait_alias(Attribute => $trait)
126 next if $class->does($trait);
128 push @traits, $trait;
131 if ($traits->[$i] && ref($traits->[$i])) {
132 $has_foreign_options = 1
133 if any { $_ ne '-alias' && $_ ne '-excludes' } keys %{ $traits->[$i] };
135 push @traits, $traits->[$i++];
141 superclasses => [ $class ],
142 roles => [ @traits ],
145 if ($has_foreign_options) {
146 $options{weaken} = 0;
152 my $anon_class = Moose::Meta::Class->create_anon_class(%options);
153 $class = $anon_class->name;
157 return ( wantarray ? ( $class, @traits ) : $class );
162 # method-generating options shouldn't be overridden
163 sub illegal_options_for_inheritance {
164 qw(reader writer accessor clearer predicate)
168 # This method *must* be able to handle
169 # Class::MOP::Attribute instances as
170 # well. Yes, I know that is wrong, but
171 # apparently we didn't realize it was
172 # doing that and now we have some code
173 # which is dependent on it. The real
174 # solution of course is to push this
175 # feature back up into Class::MOP::Attribute
176 # but I not right now, I am too lazy.
177 # However if you are reading this and
178 # looking for something to do,.. please
181 sub clone_and_inherit_options {
182 my ($self, %options) = @_;
185 # we may want to extends a Class::MOP::Attribute
186 # in which case we need to be able to use the
187 # core set of legal options that have always
188 # been here. But we allows Moose::Meta::Attribute
189 # instances to changes them.
191 my @illegal_options = $self->can('illegal_options_for_inheritance')
192 ? $self->illegal_options_for_inheritance
195 my @found_illegal_options = grep { exists $options{$_} && exists $self->{$_} ? $_ : undef } @illegal_options;
196 (scalar @found_illegal_options == 0)
197 || $self->throw_error("Illegal inherited options => (" . (join ', ' => @found_illegal_options) . ")", data => \%options);
201 if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) {
202 $type_constraint = $options{isa};
205 $type_constraint = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint($options{isa}, { package_defined_in => $options{definition_context}->{package} });
206 (defined $type_constraint)
207 || $self->throw_error("Could not find the type constraint '" . $options{isa} . "'", data => $options{isa});
210 $options{type_constraint} = $type_constraint;
213 if ($options{does}) {
215 if (blessed($options{does}) && $options{does}->isa('Moose::Meta::TypeConstraint')) {
216 $type_constraint = $options{does};
219 $type_constraint = Moose::Util::TypeConstraints::find_or_create_does_type_constraint($options{does}, { package_defined_in => $options{definition_context}->{package} });
220 (defined $type_constraint)
221 || $self->throw_error("Could not find the type constraint '" . $options{does} . "'", data => $options{does});
224 $options{type_constraint} = $type_constraint;
228 # this doesn't apply to Class::MOP::Attributes,
229 # so we can ignore it for them.
231 if ($self->can('interpolate_class')) {
232 ( $options{metaclass}, my @traits ) = $self->interpolate_class(\%options);
235 my @all_traits = grep { $seen{$_}++ } @{ $self->applied_traits || [] }, @traits;
236 $options{traits} = \@all_traits if @all_traits;
239 # This method can be called on a CMOP::Attribute object, so we need to
240 # make sure we can call this method.
241 $self->_process_lazy_build_option( $self->name, \%options )
242 if $self->can('_process_lazy_build_option');
244 $self->clone(%options);
248 my ( $self, %params ) = @_;
250 my $class = delete $params{metaclass} || ref $self;
252 my ( @init, @non_init );
254 foreach my $attr ( grep { $_->has_value($self) } Class::MOP::class_of($self)->get_all_attributes ) {
255 push @{ $attr->has_init_arg ? \@init : \@non_init }, $attr;
258 my %new_params = ( ( map { $_->init_arg => $_->get_value($self) } @init ), %params );
260 my $name = delete $new_params{name};
262 my $clone = $class->new($name, %new_params, __hack_no_process_options => 1 );
264 foreach my $attr ( @non_init ) {
265 $attr->set_value($clone, $attr->get_value($self));
271 sub _process_options {
272 my ( $class, $name, $options ) = @_;
274 $class->_process_is_option( $name, $options );
275 $class->_process_isa_option( $name, $options );
276 $class->_process_does_option( $name, $options );
277 $class->_process_coerce_option( $name, $options );
278 $class->_process_trigger_option( $name, $options );
279 $class->_process_auto_deref_option( $name, $options );
280 $class->_process_lazy_build_option( $name, $options );
281 $class->_process_lazy_option( $name, $options );
282 $class->_process_required_option( $name, $options );
285 sub _process_is_option {
286 my ( $class, $name, $options ) = @_;
288 return unless $options->{is};
290 ### -------------------------
291 ## is => ro, writer => _foo # turns into (reader => foo, writer => _foo) as before
292 ## is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
293 ## is => rw, accessor => _foo # turns into (accessor => _foo)
294 ## is => ro, accessor => _foo # error, accesor is rw
295 ### -------------------------
297 if ( $options->{is} eq 'ro' ) {
299 "Cannot define an accessor name on a read-only attribute, accessors are read/write",
301 if exists $options->{accessor};
302 $options->{reader} ||= $name;
304 elsif ( $options->{is} eq 'rw' ) {
305 if ( $options->{writer} ) {
306 $options->{reader} ||= $name;
309 $options->{accessor} ||= $name;
312 elsif ( $options->{is} eq 'bare' ) {
314 # do nothing, but don't complain (later) about missing methods
317 $class->throw_error( "I do not understand this option (is => "
319 . ") on attribute ($name)", data => $options->{is} );
323 sub _process_isa_option {
324 my ( $class, $name, $options ) = @_;
326 return unless exists $options->{isa};
328 if ( exists $options->{does} ) {
329 if ( try { $options->{isa}->can('does') } ) {
330 ( $options->{isa}->does( $options->{does} ) )
331 || $class->throw_error(
332 "Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)",
337 "Cannot have an isa option which cannot ->does() on attribute ($name)",
342 # allow for anon-subtypes here ...
343 if ( blessed( $options->{isa} )
344 && $options->{isa}->isa('Moose::Meta::TypeConstraint') ) {
345 $options->{type_constraint} = $options->{isa};
348 $options->{type_constraint}
349 = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint(
351 { package_defined_in => $options->{definition_context}->{package} }
356 sub _process_does_option {
357 my ( $class, $name, $options ) = @_;
359 return unless exists $options->{does} && ! exists $options->{isa};
361 # allow for anon-subtypes here ...
362 if ( blessed( $options->{does} )
363 && $options->{does}->isa('Moose::Meta::TypeConstraint') ) {
364 $options->{type_constraint} = $options->{does};
367 $options->{type_constraint}
368 = Moose::Util::TypeConstraints::find_or_create_does_type_constraint(
370 { package_defined_in => $options->{definition_context}->{package} }
375 sub _process_coerce_option {
376 my ( $class, $name, $options ) = @_;
378 return unless $options->{coerce};
380 ( exists $options->{type_constraint} )
381 || $class->throw_error(
382 "You cannot have coercion without specifying a type constraint on attribute ($name)",
386 "You cannot have a weak reference to a coerced value on attribute ($name)",
388 if $options->{weak_ref};
390 unless ( $options->{type_constraint}->has_coercion ) {
391 my $type = $options->{type_constraint}->name;
393 Moose::Deprecated::deprecated(
394 feature => 'coerce without coercion',
396 "You cannot coerce an attribute ($name) unless its type ($type) has a coercion"
401 sub _process_trigger_option {
402 my ( $class, $name, $options ) = @_;
404 return unless exists $options->{trigger};
406 ( 'CODE' eq ref $options->{trigger} )
407 || $class->throw_error("Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger});
410 sub _process_auto_deref_option {
411 my ( $class, $name, $options ) = @_;
413 return unless $options->{auto_deref};
415 ( exists $options->{type_constraint} )
416 || $class->throw_error(
417 "You cannot auto-dereference without specifying a type constraint on attribute ($name)",
420 ( $options->{type_constraint}->is_a_type_of('ArrayRef')
421 || $options->{type_constraint}->is_a_type_of('HashRef') )
422 || $class->throw_error(
423 "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)",
427 sub _process_lazy_build_option {
428 my ( $class, $name, $options ) = @_;
430 return unless $options->{lazy_build};
433 "You can not use lazy_build and default for the same attribute ($name)",
435 if exists $options->{default};
437 $options->{lazy} = 1;
438 $options->{builder} ||= "_build_${name}";
440 if ( $name =~ /^_/ ) {
441 $options->{clearer} ||= "_clear${name}";
442 $options->{predicate} ||= "_has${name}";
445 $options->{clearer} ||= "clear_${name}";
446 $options->{predicate} ||= "has_${name}";
450 sub _process_lazy_option {
451 my ( $class, $name, $options ) = @_;
453 return unless $options->{lazy};
455 ( exists $options->{default} || defined $options->{builder} )
456 || $class->throw_error(
457 "You cannot have a lazy attribute ($name) without specifying a default value for it",
461 sub _process_required_option {
462 my ( $class, $name, $options ) = @_;
467 ( !exists $options->{init_arg} || defined $options->{init_arg} )
468 || exists $options->{default}
469 || defined $options->{builder}
473 "You cannot have a required attribute ($name) without a default, builder, or an init_arg",
478 sub initialize_instance_slot {
479 my ($self, $meta_instance, $instance, $params) = @_;
480 my $init_arg = $self->init_arg();
481 # try to fetch the init arg from the %params ...
485 if ( defined($init_arg) and exists $params->{$init_arg}) {
486 $val = $params->{$init_arg};
490 # skip it if it's lazy
491 return if $self->is_lazy;
492 # and die if it's required and doesn't have a default value
493 $self->throw_error("Attribute (" . $self->name . ") is required", object => $instance, data => $params)
494 if $self->is_required && !$self->has_default && !$self->has_builder;
496 # if nothing was in the %params, we can use the
497 # attribute's default value (if it has one)
498 if ($self->has_default) {
499 $val = $self->default($instance);
502 elsif ($self->has_builder) {
503 $val = $self->_call_builder($instance);
508 return unless $value_is_set;
510 $val = $self->_coerce_and_verify( $val, $instance );
512 $self->set_initial_value($instance, $val);
514 if ( ref $val && $self->is_weak_ref ) {
515 $self->_weaken_value($instance);
520 my ( $self, $instance ) = @_;
522 my $builder = $self->builder();
524 return $instance->$builder()
525 if $instance->can( $self->builder );
527 $self->throw_error( blessed($instance)
528 . " does not support builder method '"
530 . "' for attribute '"
539 sub _make_initializer_writer_callback {
541 my ($meta_instance, $instance, $slot_name) = @_;
542 my $old_callback = $self->SUPER::_make_initializer_writer_callback(@_);
544 $old_callback->($self->_coerce_and_verify($_[0], $instance));
549 my ($self, $instance, @args) = @_;
550 my $value = $args[0];
552 my $attr_name = quotemeta($self->name);
554 if ($self->is_required and not @args) {
555 $self->throw_error("Attribute ($attr_name) is required", object => $instance);
558 $value = $self->_coerce_and_verify( $value, $instance );
561 if ( $self->has_trigger && $self->has_value($instance) ) {
562 @old = $self->get_value($instance, 'for trigger');
565 $self->SUPER::set_value($instance, $value);
567 if ( ref $value && $self->is_weak_ref ) {
568 $self->_weaken_value($instance);
571 if ($self->has_trigger) {
572 $self->trigger->($instance, $value, @old);
576 sub _inline_set_value {
578 my ($instance, $value, $tc, $coercion, $message, $for_constructor) = @_;
582 $tc ||= '$type_constraint';
583 $coercion ||= '$type_coercion';
584 $message ||= '$type_message';
587 if ($self->_writer_value_needs_copy) {
588 push @code, $self->_inline_copy_value($value, $copy);
592 # constructors already handle required checks
593 push @code, $self->_inline_check_required
594 unless $for_constructor;
596 push @code, $self->_inline_tc_code($value, $tc, $coercion, $message);
598 # constructors do triggers all at once at the end
599 push @code, $self->_inline_get_old_value_for_trigger($instance, $old)
600 unless $for_constructor;
603 $self->SUPER::_inline_set_value($instance, $value),
604 $self->_inline_weaken_value($instance, $value),
607 # constructors do triggers all at once at the end
608 push @code, $self->_inline_trigger($instance, $value, $old)
609 unless $for_constructor;
614 sub _writer_value_needs_copy {
616 return $self->should_coerce;
619 sub _inline_copy_value {
621 my ($value, $copy) = @_;
623 return 'my ' . $copy . ' = ' . $value . ';'
626 sub _inline_check_required {
629 return unless $self->is_required;
631 my $attr_name = quotemeta($self->name);
635 $self->_inline_throw_error(
636 '"Attribute (' . $attr_name . ') is required, so cannot '
637 . 'be set to undef"' # defined $_[1] is not good enough
643 sub _inline_tc_code {
645 my ($value, $tc, $coercion, $message, $is_lazy) = @_;
647 $self->_inline_check_coercion(
648 $value, $tc, $coercion, $is_lazy,
650 $self->_inline_check_constraint(
651 $value, $tc, $message, $is_lazy,
656 sub _inline_check_coercion {
658 my ($value, $tc, $coercion) = @_;
660 return unless $self->should_coerce && $self->type_constraint->has_coercion;
662 if ( $self->type_constraint->can_be_inlined ) {
664 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
665 $value . ' = ' . $coercion . '->(' . $value . ');',
671 'if (!' . $tc . '->(' . $value . ')) {',
672 $value . ' = ' . $coercion . '->(' . $value . ');',
678 sub _inline_check_constraint {
680 my ($value, $tc, $message) = @_;
682 return unless $self->has_type_constraint;
684 my $attr_name = quotemeta($self->name);
686 if ( $self->type_constraint->can_be_inlined ) {
688 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
689 $self->_inline_throw_error(
690 '"Attribute (' . $attr_name . ') does not pass the type '
691 . 'constraint because: " . '
692 . 'do { local $_ = ' . $value . '; '
693 . $message . '->(' . $value . ')'
702 'if (!' . $tc . '->(' . $value . ')) {',
703 $self->_inline_throw_error(
704 '"Attribute (' . $attr_name . ') does not pass the type '
705 . 'constraint because: " . '
706 . 'do { local $_ = ' . $value . '; '
707 . $message . '->(' . $value . ')'
716 sub _inline_get_old_value_for_trigger {
718 my ($instance, $old) = @_;
720 return unless $self->has_trigger;
723 'my ' . $old . ' = ' . $self->_inline_instance_has($instance),
724 '? ' . $self->_inline_instance_get($instance),
729 sub _inline_weaken_value {
731 my ($instance, $value) = @_;
733 return unless $self->is_weak_ref;
735 my $mi = $self->associated_class->get_meta_instance;
737 $mi->inline_weaken_slot_value($instance, $self->name),
738 'if ref ' . $value . ';',
742 sub _inline_trigger {
744 my ($instance, $value, $old) = @_;
746 return unless $self->has_trigger;
748 return '$trigger->(' . $instance . ', ' . $value . ', ' . $old . ');';
751 sub _eval_environment {
756 $env->{'$trigger'} = \($self->trigger)
757 if $self->has_trigger;
758 $env->{'$attr_default'} = \($self->default)
759 if $self->has_default;
761 if ($self->has_type_constraint) {
762 my $tc_obj = $self->type_constraint;
764 $env->{'$type_constraint'} = \(
765 $tc_obj->_compiled_type_constraint
766 ) unless $tc_obj->can_be_inlined;
767 # these two could probably get inlined versions too
768 $env->{'$type_coercion'} = \(
769 $tc_obj->coercion->_compiled_type_coercion
770 ) if $tc_obj->has_coercion;
771 $env->{'$type_message'} = \(
772 $tc_obj->has_message ? $tc_obj->message : $tc_obj->_default_message
775 $env = { %$env, %{ $tc_obj->inline_environment } };
779 $env->{'$attr'} = \$self
780 if $self->has_initializer && $self->is_lazy;
781 # pretty sure this is only going to be closed over if you use a custom
782 # error class at this point, but we should still get rid of this
784 $env->{'$meta'} = \($self->associated_class);
790 my ( $self, $instance ) = @_;
792 my $meta_instance = Class::MOP::Class->initialize( blessed($instance) )
795 $meta_instance->weaken_slot_value( $instance, $self->name );
799 my ($self, $instance, $for_trigger) = @_;
801 if ($self->is_lazy) {
802 unless ($self->has_value($instance)) {
804 if ($self->has_default) {
805 $value = $self->default($instance);
806 } elsif ( $self->has_builder ) {
807 $value = $self->_call_builder($instance);
810 $value = $self->_coerce_and_verify( $value, $instance );
812 $self->set_initial_value($instance, $value);
814 if ( ref $value && $self->is_weak_ref ) {
815 $self->_weaken_value($instance);
820 if ( $self->should_auto_deref && ! $for_trigger ) {
822 my $type_constraint = $self->type_constraint;
824 if ($type_constraint->is_a_type_of('ArrayRef')) {
825 my $rv = $self->SUPER::get_value($instance);
826 return unless defined $rv;
827 return wantarray ? @{ $rv } : $rv;
829 elsif ($type_constraint->is_a_type_of('HashRef')) {
830 my $rv = $self->SUPER::get_value($instance);
831 return unless defined $rv;
832 return wantarray ? %{ $rv } : $rv;
835 $self->throw_error("Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint);
841 return $self->SUPER::get_value($instance);
845 sub _inline_get_value {
847 my ($instance, $tc, $coercion, $message) = @_;
849 my $slot_access = $self->_inline_instance_get($instance);
850 $tc ||= '$type_constraint';
851 $coercion ||= '$type_coercion';
852 $message ||= '$type_message';
855 $self->_inline_check_lazy($instance, $tc, $coercion, $message),
856 $self->_inline_return_auto_deref($slot_access),
860 sub _inline_check_lazy {
862 my ($instance, $tc, $coercion, $message) = @_;
864 return unless $self->is_lazy;
866 my $slot_exists = $self->_inline_instance_has($instance);
869 'if (!' . $slot_exists . ') {',
870 $self->_inline_init_from_default($instance, '$default', $tc, $coercion, $message, 'lazy'),
875 sub _inline_init_from_default {
877 my ($instance, $default, $tc, $coercion, $message, $for_lazy) = @_;
879 if (!($self->has_default || $self->has_builder)) {
881 'You cannot have a lazy attribute '
882 . '(' . $self->name . ') '
883 . 'without specifying a default value for it',
889 $self->_inline_generate_default($instance, $default),
890 # intentionally not using _inline_tc_code, since that can be overridden
891 # to do things like possibly only do member tc checks, which isn't
892 # appropriate for checking the result of a default
893 $self->has_type_constraint
894 ? ($self->_inline_check_coercion($default, $tc, $coercion, $for_lazy),
895 $self->_inline_check_constraint($default, $tc, $message, $for_lazy))
897 $self->_inline_init_slot($instance, $default),
898 $self->_inline_weaken_value($instance, $default),
902 sub _inline_generate_default {
904 my ($instance, $default) = @_;
906 if ($self->has_default) {
907 my $source = 'my ' . $default . ' = $attr_default';
908 $source .= '->(' . $instance . ')'
909 if $self->is_default_a_coderef;
910 return $source . ';';
912 elsif ($self->has_builder) {
913 my $builder = B::perlstring($self->builder);
914 my $builder_str = quotemeta($self->builder);
915 my $attr_name_str = quotemeta($self->name);
917 'my ' . $default . ';',
918 'if (my $builder = ' . $instance . '->can(' . $builder . ')) {',
919 $default . ' = ' . $instance . '->$builder;',
922 'my $class = ref(' . $instance . ') || ' . $instance . ';',
923 $self->_inline_throw_error(
924 '"$class does not support builder method '
925 . '\'' . $builder_str . '\' for attribute '
926 . '\'' . $attr_name_str . '\'"'
933 "Can't generate a default for " . $self->name
934 . " since no default or builder was specified"
939 sub _inline_init_slot {
941 my ($inv, $value) = @_;
943 if ($self->has_initializer) {
944 return '$attr->set_initial_value(' . $inv . ', ' . $value . ');';
947 return $self->_inline_instance_set($inv, $value) . ';';
951 sub _inline_return_auto_deref {
954 return 'return ' . $self->_auto_deref(@_) . ';';
959 my ($ref_value) = @_;
961 return $ref_value unless $self->should_auto_deref;
963 my $type_constraint = $self->type_constraint;
966 if ($type_constraint->is_a_type_of('ArrayRef')) {
969 elsif ($type_constraint->is_a_type_of('HashRef')) {
974 'Can not auto de-reference the type constraint \''
975 . $type_constraint->name
977 type_constraint => $type_constraint,
982 . '? ' . $sigil . '{ (' . $ref_value . ') || return } '
983 . ': (' . $ref_value . ')';
986 ## installing accessors
988 sub accessor_metaclass { 'Moose::Meta::Method::Accessor' }
990 sub install_accessors {
992 $self->SUPER::install_accessors(@_);
993 $self->install_delegation if $self->has_handles;
997 sub _check_associated_methods {
1000 @{ $self->associated_methods }
1001 || ($self->_is_metadata || '') eq 'bare'
1004 'Attribute (' . $self->name . ') of class '
1005 . $self->associated_class->name
1006 . ' has no associated methods'
1007 . ' (did you mean to provide an "is" argument?)'
1013 sub _process_accessors {
1015 my ($type, $accessor, $generate_as_inline_methods) = @_;
1017 $accessor = ( keys %$accessor )[0] if ( ref($accessor) || '' ) eq 'HASH';
1018 my $method = $self->associated_class->get_method($accessor);
1021 && $method->isa('Class::MOP::Method::Accessor')
1022 && $method->associated_attribute->name ne $self->name ) {
1024 my $other_attr_name = $method->associated_attribute->name;
1025 my $name = $self->name;
1028 "You are overwriting an accessor ($accessor) for the $other_attr_name attribute"
1029 . " with a new accessor method for the $name attribute" );
1034 && !$method->is_stub
1035 && !$method->isa('Class::MOP::Method::Accessor')
1036 && ( !$self->definition_context
1037 || $method->package_name eq $self->definition_context->{package} )
1041 "You are overwriting a locally defined method ($accessor) with "
1045 if ( !$self->associated_class->has_method($accessor)
1046 && $self->associated_class->has_package_symbol( '&' . $accessor ) ) {
1049 "You are overwriting a locally defined function ($accessor) with "
1053 $self->SUPER::_process_accessors(@_);
1056 sub remove_accessors {
1058 $self->SUPER::remove_accessors(@_);
1059 $self->remove_delegation if $self->has_handles;
1063 sub install_delegation {
1067 # Here we canonicalize the 'handles' option
1068 # this will sort out any details and always
1069 # return an hash of methods which we want
1070 # to delagate to, see that method for details
1071 my %handles = $self->_canonicalize_handles;
1074 # install the delegation ...
1075 my $associated_class = $self->associated_class;
1076 foreach my $handle (sort keys %handles) {
1077 my $method_to_call = $handles{$handle};
1078 my $class_name = $associated_class->name;
1079 my $name = "${class_name}::${handle}";
1081 if ( my $method = $associated_class->get_method($handle) ) {
1083 "You cannot overwrite a locally defined method ($handle) with a delegation",
1084 method_name => $handle
1085 ) unless $method->is_stub;
1089 # handles is not allowed to delegate
1090 # any of these methods, as they will
1091 # override the ones in your class, which
1092 # is almost certainly not what you want.
1094 # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something
1095 #cluck("Not delegating method '$handle' because it is a core method") and
1096 next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle);
1098 my $method = $self->_make_delegation_method($handle, $method_to_call);
1100 $self->associated_class->add_method($method->name, $method);
1101 $self->associate_method($method);
1105 sub remove_delegation {
1107 my %handles = $self->_canonicalize_handles;
1108 my $associated_class = $self->associated_class;
1109 foreach my $handle (keys %handles) {
1110 next unless any { $handle eq $_ }
1112 @{ $self->associated_methods };
1113 $self->associated_class->remove_method($handle);
1117 # private methods to help delegation ...
1119 sub _canonicalize_handles {
1121 my $handles = $self->handles;
1122 if (my $handle_type = ref($handles)) {
1123 if ($handle_type eq 'HASH') {
1126 elsif ($handle_type eq 'ARRAY') {
1127 return map { $_ => $_ } @{$handles};
1129 elsif ($handle_type eq 'Regexp') {
1130 ($self->has_type_constraint)
1131 || $self->throw_error("Cannot delegate methods based on a Regexp without a type constraint (isa)", data => $handles);
1132 return map { ($_ => $_) }
1133 grep { /$handles/ } $self->_get_delegate_method_list;
1135 elsif ($handle_type eq 'CODE') {
1136 return $handles->($self, $self->_find_delegate_metaclass);
1138 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::DuckType')) {
1139 return map { $_ => $_ } @{ $handles->methods };
1141 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::Role')) {
1142 $handles = $handles->role;
1145 $self->throw_error("Unable to canonicalize the 'handles' option with $handles", data => $handles);
1149 load_class($handles);
1150 my $role_meta = Class::MOP::class_of($handles);
1152 (blessed $role_meta && $role_meta->isa('Moose::Meta::Role'))
1153 || $self->throw_error("Unable to canonicalize the 'handles' option with $handles because its metaclass is not a Moose::Meta::Role", data => $handles);
1155 return map { $_ => $_ }
1157 grep { !$_->isa('Class::MOP::Method::Meta') } (
1158 $role_meta->_get_local_methods,
1159 $role_meta->get_required_method_list,
1163 sub _get_delegate_method_list {
1165 my $meta = $self->_find_delegate_metaclass;
1166 if ($meta->isa('Class::MOP::Class')) {
1167 return map { $_->name } # NOTE: !never! delegate &meta
1168 grep { $_->package_name ne 'Moose::Object' && !$_->isa('Class::MOP::Method::Meta') }
1169 $meta->get_all_methods;
1171 elsif ($meta->isa('Moose::Meta::Role')) {
1172 return $meta->get_method_list;
1175 $self->throw_error("Unable to recognize the delegate metaclass '$meta'", data => $meta);
1179 sub _find_delegate_metaclass {
1181 if (my $class = $self->_isa_metadata) {
1182 unless ( is_class_loaded($class) ) {
1185 'The %s attribute is trying to delegate to a class which has not been loaded - %s',
1190 # we might be dealing with a non-Moose class,
1191 # and need to make our own metaclass. if there's
1192 # already a metaclass, it will be returned
1193 return Class::MOP::Class->initialize($class);
1195 elsif (my $role = $self->_does_metadata) {
1196 unless ( is_class_loaded($class) ) {
1199 'The %s attribute is trying to delegate to a role which has not been loaded - %s',
1205 return Class::MOP::class_of($role);
1208 $self->throw_error("Cannot find delegate metaclass for attribute " . $self->name);
1212 sub delegation_metaclass { 'Moose::Meta::Method::Delegation' }
1214 sub _make_delegation_method {
1215 my ( $self, $handle_name, $method_to_call ) = @_;
1217 my @curried_arguments;
1219 ($method_to_call, @curried_arguments) = @$method_to_call
1220 if 'ARRAY' eq ref($method_to_call);
1222 return $self->delegation_metaclass->new(
1223 name => $handle_name,
1224 package_name => $self->associated_class->name,
1226 delegate_to_method => $method_to_call,
1227 curried_arguments => \@curried_arguments,
1231 sub _coerce_and_verify {
1234 my $instance = shift;
1236 return $val unless $self->has_type_constraint;
1238 $val = $self->type_constraint->coerce($val)
1239 if $self->should_coerce && $self->type_constraint->has_coercion;
1241 $self->verify_against_type_constraint($val, instance => $instance);
1246 sub verify_against_type_constraint {
1250 return 1 if !$self->has_type_constraint;
1252 my $type_constraint = $self->type_constraint;
1254 $type_constraint->check($val)
1255 || $self->throw_error("Attribute ("
1257 . ") does not pass the type constraint because: "
1258 . $type_constraint->get_message($val), data => $val, @_);
1261 package Moose::Meta::Attribute::Custom::Moose;
1262 sub register_implementation { 'Moose::Meta::Attribute' }
1266 # ABSTRACT: The Moose attribute metaclass
1274 This class is a subclass of L<Class::MOP::Attribute> that provides
1275 additional Moose-specific functionality.
1277 To really understand this class, you will need to start with the
1278 L<Class::MOP::Attribute> documentation. This class can be understood
1279 as a set of additional features on top of the basic feature provided
1280 by that parent class.
1284 C<Moose::Meta::Attribute> is a subclass of L<Class::MOP::Attribute>.
1288 Many of the documented below override methods in
1289 L<Class::MOP::Attribute> and add Moose specific features.
1295 =item B<< Moose::Meta::Attribute->new(%options) >>
1297 This method overrides the L<Class::MOP::Attribute> constructor.
1299 Many of the options below are described in more detail in the
1300 L<Moose::Manual::Attributes> document.
1302 It adds the following options to the constructor:
1306 =item * is => 'ro', 'rw', 'bare'
1308 This provides a shorthand for specifying the C<reader>, C<writer>, or
1309 C<accessor> names. If the attribute is read-only ('ro') then it will
1310 have a C<reader> method with the same attribute as the name.
1312 If it is read-write ('rw') then it will have an C<accessor> method
1313 with the same name. If you provide an explicit C<writer> for a
1314 read-write attribute, then you will have a C<reader> with the same
1315 name as the attribute, and a C<writer> with the name you provided.
1317 Use 'bare' when you are deliberately not installing any methods
1318 (accessor, reader, etc.) associated with this attribute; otherwise,
1319 Moose will issue a deprecation warning when this attribute is added to a
1322 =item * isa => $type
1324 This option accepts a type. The type can be a string, which should be
1325 a type name. If the type name is unknown, it is assumed to be a class
1328 This option can also accept a L<Moose::Meta::TypeConstraint> object.
1330 If you I<also> provide a C<does> option, then your C<isa> option must
1331 be a class name, and that class must do the role specified with
1334 =item * does => $role
1336 This is short-hand for saying that the attribute's type must be an
1337 object which does the named role.
1339 =item * coerce => $bool
1341 This option is only valid for objects with a type constraint
1342 (C<isa>) that defined a coercion. If this is true, then coercions will be applied whenever
1343 this attribute is set.
1345 You can make both this and the C<weak_ref> option true.
1347 =item * trigger => $sub
1349 This option accepts a subroutine reference, which will be called after
1350 the attribute is set.
1352 =item * required => $bool
1354 An attribute which is required must be provided to the constructor. An
1355 attribute which is required can also have a C<default> or C<builder>,
1356 which will satisfy its required-ness.
1358 A required attribute must have a C<default>, C<builder> or a
1359 non-C<undef> C<init_arg>
1361 =item * lazy => $bool
1363 A lazy attribute must have a C<default> or C<builder>. When an
1364 attribute is lazy, the default value will not be calculated until the
1367 =item * weak_ref => $bool
1369 If this is true, the attribute's value will be stored as a weak
1372 =item * auto_deref => $bool
1374 If this is true, then the reader will dereference the value when it is
1375 called. The attribute must have a type constraint which defines the
1376 attribute as an array or hash reference.
1378 =item * lazy_build => $bool
1380 Setting this to true makes the attribute lazy and provides a number of
1388 is equivalent to this:
1393 builder => '_build_size',
1394 clearer => 'clear_size',
1395 predicate => 'has_size',
1399 If your attribute name starts with an underscore (C<_>), then the clearer
1400 and predicate will as well:
1412 builder => '_build__size',
1413 clearer => '_clear_size',
1414 predicate => '_has_size',
1417 Note the doubled underscore in the builder name. Internally, Moose
1418 simply prepends the attribute name with "_build_" to come up with the
1421 =item * documentation
1423 An arbitrary string that can be retrieved later by calling C<<
1424 $attr->documentation >>.
1428 =item B<< $attr->clone(%options) >>
1430 This creates a new attribute based on attribute being cloned. You must
1431 supply a C<name> option to provide a new name for the attribute.
1433 The C<%options> can only specify options handled by
1434 L<Class::MOP::Attribute>.
1438 =head2 Value management
1442 =item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >>
1444 This method is used internally to initialize the attribute's slot in
1445 the object C<$instance>.
1447 This overrides the L<Class::MOP::Attribute> method to handle lazy
1448 attributes, weak references, and type constraints.
1454 eval { $point->meta->get_attribute('x')->set_value($point, 'forty-two') };
1459 I<Attribute (x) does not pass the type constraint (Int) with 'forty-two'>
1461 Before setting the value, a check is made on the type constraint of
1462 the attribute, if it has one, to see if the value passes it. If the
1463 value fails to pass, the set operation dies.
1465 Any coercion to convert values is done before checking the type constraint.
1467 To check a value against a type constraint before setting it, fetch the
1468 attribute instance using L<Class::MOP::Class/find_attribute_by_name>,
1469 fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint>
1470 and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Company_Subtypes>
1475 =head2 Attribute Accessor generation
1479 =item B<< $attr->install_accessors >>
1481 This method overrides the parent to also install delegation methods.
1483 If, after installing all methods, the attribute object has no associated
1484 methods, it throws an error unless C<< is => 'bare' >> was passed to the
1485 attribute constructor. (Trying to add an attribute that has no associated
1486 methods is almost always an error.)
1488 =item B<< $attr->remove_accessors >>
1490 This method overrides the parent to also remove delegation methods.
1492 =item B<< $attr->inline_set($instance_var, $value_var) >>
1494 This method return a code snippet suitable for inlining the relevant
1495 operation. It expect strings containing variable names to be used in the
1496 inlining, like C<'$self'> or C<'$_[1]'>.
1498 =item B<< $attr->install_delegation >>
1500 This method adds its delegation methods to the attribute's associated
1501 class, if it has any to add.
1503 =item B<< $attr->remove_delegation >>
1505 This method remove its delegation methods from the attribute's
1508 =item B<< $attr->accessor_metaclass >>
1510 Returns the accessor metaclass name, which defaults to
1511 L<Moose::Meta::Method::Accessor>.
1513 =item B<< $attr->delegation_metaclass >>
1515 Returns the delegation metaclass name, which defaults to
1516 L<Moose::Meta::Method::Delegation>.
1520 =head2 Additional Moose features
1522 These methods are not found in the superclass. They support features
1527 =item B<< $attr->does($role) >>
1529 This indicates whether the I<attribute itself> does the given
1530 role. The role can be given as a full class name, or as a resolvable
1533 Note that this checks the attribute itself, not its type constraint,
1534 so it is checking the attribute's metaclass and any traits applied to
1537 =item B<< Moose::Meta::Class->interpolate_class_and_new($name, %options) >>
1539 This is an alternate constructor that handles the C<metaclass> and
1542 Effectively, this method is a factory that finds or creates the
1543 appropriate class for the given C<metaclass> and/or C<traits>.
1545 Once it has the appropriate class, it will call C<< $class->new($name,
1546 %options) >> on that class.
1548 =item B<< $attr->clone_and_inherit_options(%options) >>
1550 This method supports the C<has '+foo'> feature. It does various bits
1551 of processing on the supplied C<%options> before ultimately calling
1552 the C<clone> method.
1554 One of its main tasks is to make sure that the C<%options> provided
1555 does not include the options returned by the
1556 C<illegal_options_for_inheritance> method.
1558 =item B<< $attr->illegal_options_for_inheritance >>
1560 This returns a blacklist of options that can not be overridden in a
1561 subclass's attribute definition.
1563 This exists to allow a custom metaclass to change or add to the list
1564 of options which can not be changed.
1566 =item B<< $attr->type_constraint >>
1568 Returns the L<Moose::Meta::TypeConstraint> object for this attribute,
1571 =item B<< $attr->has_type_constraint >>
1573 Returns true if this attribute has a type constraint.
1575 =item B<< $attr->verify_against_type_constraint($value) >>
1577 Given a value, this method returns true if the value is valid for the
1578 attribute's type constraint. If the value is not valid, it throws an
1581 =item B<< $attr->handles >>
1583 This returns the value of the C<handles> option passed to the
1586 =item B<< $attr->has_handles >>
1588 Returns true if this attribute performs delegation.
1590 =item B<< $attr->is_weak_ref >>
1592 Returns true if this attribute stores its value as a weak reference.
1594 =item B<< $attr->is_required >>
1596 Returns true if this attribute is required to have a value.
1598 =item B<< $attr->is_lazy >>
1600 Returns true if this attribute is lazy.
1602 =item B<< $attr->is_lazy_build >>
1604 Returns true if the C<lazy_build> option was true when passed to the
1607 =item B<< $attr->should_coerce >>
1609 Returns true if the C<coerce> option passed to the constructor was
1612 =item B<< $attr->should_auto_deref >>
1614 Returns true if the C<auto_deref> option passed to the constructor was
1617 =item B<< $attr->trigger >>
1619 This is the subroutine reference that was in the C<trigger> option
1620 passed to the constructor, if any.
1622 =item B<< $attr->has_trigger >>
1624 Returns true if this attribute has a trigger set.
1626 =item B<< $attr->documentation >>
1628 Returns the value that was in the C<documentation> option passed to
1629 the constructor, if any.
1631 =item B<< $attr->has_documentation >>
1633 Returns true if this attribute has any documentation.
1635 =item B<< $attr->applied_traits >>
1637 This returns an array reference of all the traits which were applied
1638 to this attribute. If none were applied, this returns C<undef>.
1640 =item B<< $attr->has_applied_traits >>
1642 Returns true if this attribute has any traits applied.
1648 See L<Moose/BUGS> for details on reporting bugs.