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 || $self->throw_error(message => "Illegal inherited options => (" . (join ', ' => @found_illegal_options) . ")", data => \%options);
201 if (blessed($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(message => "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(message => "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 message => "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 ( $options->{is} eq 'bare' ) {
314 # do nothing, but don't complain (later) about missing methods
318 message => "I do not understand this option (is => "
320 . ") on attribute ($name)", data => $options->{is}
325 sub _process_isa_option {
326 my ( $class, $name, $options ) = @_;
328 return unless exists $options->{isa};
330 if ( exists $options->{does} ) {
331 if ( try { $options->{isa}->can('does') } ) {
332 ( $options->{isa}->does( $options->{does} ) )
333 || $class->throw_error(
334 message => "Cannot have an isa option and a does option if the isa does not do the does on attribute ($name)",
339 message => "Cannot have an isa option which cannot ->does() on attribute ($name)",
344 # allow for anon-subtypes here ...
345 if ( blessed( $options->{isa} )
346 && $options->{isa}->isa('Moose::Meta::TypeConstraint') ) {
347 $options->{type_constraint} = $options->{isa};
350 $options->{type_constraint}
351 = Moose::Util::TypeConstraints::find_or_create_isa_type_constraint(
353 { package_defined_in => $options->{definition_context}->{package} }
358 sub _process_does_option {
359 my ( $class, $name, $options ) = @_;
361 return unless exists $options->{does} && ! exists $options->{isa};
363 # allow for anon-subtypes here ...
364 if ( blessed( $options->{does} )
365 && $options->{does}->isa('Moose::Meta::TypeConstraint') ) {
366 $options->{type_constraint} = $options->{does};
369 $options->{type_constraint}
370 = Moose::Util::TypeConstraints::find_or_create_does_type_constraint(
372 { package_defined_in => $options->{definition_context}->{package} }
377 sub _process_coerce_option {
378 my ( $class, $name, $options ) = @_;
380 return unless $options->{coerce};
382 ( exists $options->{type_constraint} )
383 || $class->throw_error(
384 message => "You cannot have coercion without specifying a type constraint on attribute ($name)",
388 message => "You cannot have a weak reference to a coerced value on attribute ($name)",
390 if $options->{weak_ref};
392 unless ( $options->{type_constraint}->has_coercion ) {
393 my $type = $options->{type_constraint}->name;
395 Moose::Deprecated::deprecated(
396 feature => 'coerce without coercion',
398 "You cannot coerce an attribute ($name) unless its type ($type) has a coercion"
403 sub _process_trigger_option {
404 my ( $class, $name, $options ) = @_;
406 return unless exists $options->{trigger};
408 ( 'CODE' eq ref $options->{trigger} )
409 || $class->throw_error(message => "Trigger must be a CODE ref on attribute ($name)", data => $options->{trigger});
412 sub _process_auto_deref_option {
413 my ( $class, $name, $options ) = @_;
415 return unless $options->{auto_deref};
417 ( exists $options->{type_constraint} )
418 || $class->throw_error(
419 message => "You cannot auto-dereference without specifying a type constraint on attribute ($name)",
422 ( $options->{type_constraint}->is_a_type_of('ArrayRef')
423 || $options->{type_constraint}->is_a_type_of('HashRef') )
424 || $class->throw_error(
425 message => "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)",
429 sub _process_lazy_build_option {
430 my ( $class, $name, $options ) = @_;
432 return unless $options->{lazy_build};
435 message => "You can not use lazy_build and default for the same attribute ($name)",
437 if exists $options->{default};
439 $options->{lazy} = 1;
440 $options->{builder} ||= "_build_${name}";
442 if ( $name =~ /^_/ ) {
443 $options->{clearer} ||= "_clear${name}";
444 $options->{predicate} ||= "_has${name}";
447 $options->{clearer} ||= "clear_${name}";
448 $options->{predicate} ||= "has_${name}";
452 sub _process_lazy_option {
453 my ( $class, $name, $options ) = @_;
455 return unless $options->{lazy};
457 ( exists $options->{default} || defined $options->{builder} )
458 || $class->throw_error(
459 message => "You cannot have a lazy attribute ($name) without specifying a default value for it",
463 sub _process_required_option {
464 my ( $class, $name, $options ) = @_;
469 ( !exists $options->{init_arg} || defined $options->{init_arg} )
470 || exists $options->{default}
471 || defined $options->{builder}
475 message => "You cannot have a required attribute ($name) without a default, builder, or an init_arg",
480 sub initialize_instance_slot {
481 my ($self, $meta_instance, $instance, $params) = @_;
482 my $init_arg = $self->init_arg();
483 # try to fetch the init arg from the %params ...
487 if ( defined($init_arg) and exists $params->{$init_arg}) {
488 $val = $params->{$init_arg};
492 # skip it if it's lazy
493 return if $self->is_lazy;
494 # and die if it's required and doesn't have a default value
495 $self->throw_error(message => "Attribute (" . $self->name . ") is required", object => $instance, data => $params)
496 if $self->is_required && !$self->has_default && !$self->has_builder;
498 # if nothing was in the %params, we can use the
499 # attribute's default value (if it has one)
500 if ($self->has_default) {
501 $val = $self->default($instance);
504 elsif ($self->has_builder) {
505 $val = $self->_call_builder($instance);
510 return unless $value_is_set;
512 $val = $self->_coerce_and_verify( $val, $instance );
514 $self->set_initial_value($instance, $val);
516 if ( ref $val && $self->is_weak_ref ) {
517 $self->_weaken_value($instance);
522 my ( $self, $instance ) = @_;
524 my $builder = $self->builder();
526 return $instance->$builder()
527 if $instance->can( $self->builder );
530 message => blessed($instance)
531 . " does not support builder method '"
533 . "' for attribute '"
542 sub _make_initializer_writer_callback {
544 my ($meta_instance, $instance, $slot_name) = @_;
545 my $old_callback = $self->SUPER::_make_initializer_writer_callback(@_);
547 $old_callback->($self->_coerce_and_verify($_[0], $instance));
552 my ($self, $instance, @args) = @_;
553 my $value = $args[0];
555 my $attr_name = quotemeta($self->name);
557 if ($self->is_required and not @args) {
558 $self->throw_error(message => "Attribute ($attr_name) is required", object => $instance);
561 $value = $self->_coerce_and_verify( $value, $instance );
564 if ( $self->has_trigger && $self->has_value($instance) ) {
565 @old = $self->get_value($instance, 'for trigger');
568 $self->SUPER::set_value($instance, $value);
570 if ( ref $value && $self->is_weak_ref ) {
571 $self->_weaken_value($instance);
574 if ($self->has_trigger) {
575 $self->trigger->($instance, $value, @old);
579 sub _inline_set_value {
581 my ($instance, $value, $tc, $coercion, $message, $for_constructor) = @_;
585 $tc ||= '$type_constraint';
586 $coercion ||= '$type_coercion';
587 $message ||= '$type_message';
590 if ($self->_writer_value_needs_copy) {
591 push @code, $self->_inline_copy_value($value, $copy);
595 # constructors already handle required checks
596 push @code, $self->_inline_check_required
597 unless $for_constructor;
599 push @code, $self->_inline_tc_code($value, $tc, $coercion, $message);
601 # constructors do triggers all at once at the end
602 push @code, $self->_inline_get_old_value_for_trigger($instance, $old)
603 unless $for_constructor;
606 $self->SUPER::_inline_set_value($instance, $value),
607 $self->_inline_weaken_value($instance, $value),
610 # constructors do triggers all at once at the end
611 push @code, $self->_inline_trigger($instance, $value, $old)
612 unless $for_constructor;
617 sub _writer_value_needs_copy {
619 return $self->should_coerce;
622 sub _inline_copy_value {
624 my ($value, $copy) = @_;
626 return 'my ' . $copy . ' = ' . $value . ';'
629 sub _inline_check_required {
632 return unless $self->is_required;
634 my $attr_name = quotemeta($self->name);
638 $self->_inline_throw_error(
639 '"Attribute (' . $attr_name . ') is required, so cannot '
640 . 'be set to undef"' # defined $_[1] is not good enough
646 sub _inline_tc_code {
648 my ($value, $tc, $coercion, $message, $is_lazy) = @_;
650 $self->_inline_check_coercion(
651 $value, $tc, $coercion, $is_lazy,
653 $self->_inline_check_constraint(
654 $value, $tc, $message, $is_lazy,
659 sub _inline_check_coercion {
661 my ($value, $tc, $coercion) = @_;
663 return unless $self->should_coerce && $self->type_constraint->has_coercion;
665 if ( $self->type_constraint->can_be_inlined ) {
667 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
668 $value . ' = ' . $coercion . '->(' . $value . ');',
674 'if (!' . $tc . '->(' . $value . ')) {',
675 $value . ' = ' . $coercion . '->(' . $value . ');',
681 sub _inline_check_constraint {
683 my ($value, $tc, $message) = @_;
685 return unless $self->has_type_constraint;
687 my $attr_name = quotemeta($self->name);
689 if ( $self->type_constraint->can_be_inlined ) {
691 'if (! (' . $self->type_constraint->_inline_check($value) . ')) {',
692 $self->_inline_throw_error(
693 '"Attribute (' . $attr_name . ') does not pass the type '
694 . 'constraint because: " . '
695 . 'do { local $_ = ' . $value . '; '
696 . $message . '->(' . $value . ')'
705 'if (!' . $tc . '->(' . $value . ')) {',
706 $self->_inline_throw_error(
707 '"Attribute (' . $attr_name . ') does not pass the type '
708 . 'constraint because: " . '
709 . 'do { local $_ = ' . $value . '; '
710 . $message . '->(' . $value . ')'
719 sub _inline_get_old_value_for_trigger {
721 my ($instance, $old) = @_;
723 return unless $self->has_trigger;
726 'my ' . $old . ' = ' . $self->_inline_instance_has($instance),
727 '? ' . $self->_inline_instance_get($instance),
732 sub _inline_weaken_value {
734 my ($instance, $value) = @_;
736 return unless $self->is_weak_ref;
738 my $mi = $self->associated_class->get_meta_instance;
740 $mi->inline_weaken_slot_value($instance, $self->name),
741 'if ref ' . $value . ';',
745 sub _inline_trigger {
747 my ($instance, $value, $old) = @_;
749 return unless $self->has_trigger;
751 return '$trigger->(' . $instance . ', ' . $value . ', ' . $old . ');';
754 sub _eval_environment {
759 $env->{'$trigger'} = \($self->trigger)
760 if $self->has_trigger;
761 $env->{'$attr_default'} = \($self->default)
762 if $self->has_default;
764 if ($self->has_type_constraint) {
765 my $tc_obj = $self->type_constraint;
767 $env->{'$type_constraint'} = \(
768 $tc_obj->_compiled_type_constraint
769 ) unless $tc_obj->can_be_inlined;
770 # these two could probably get inlined versions too
771 $env->{'$type_coercion'} = \(
772 $tc_obj->coercion->_compiled_type_coercion
773 ) if $tc_obj->has_coercion;
774 $env->{'$type_message'} = \(
775 $tc_obj->has_message ? $tc_obj->message : $tc_obj->_default_message
778 $env = { %$env, %{ $tc_obj->inline_environment } };
782 $env->{'$attr'} = \$self
783 if $self->has_initializer && $self->is_lazy;
784 # pretty sure this is only going to be closed over if you use a custom
785 # error class at this point, but we should still get rid of this
787 $env->{'$meta'} = \($self->associated_class);
793 my ( $self, $instance ) = @_;
795 my $meta_instance = Class::MOP::Class->initialize( blessed($instance) )
798 $meta_instance->weaken_slot_value( $instance, $self->name );
802 my ($self, $instance, $for_trigger) = @_;
804 if ($self->is_lazy) {
805 unless ($self->has_value($instance)) {
807 if ($self->has_default) {
808 $value = $self->default($instance);
809 } elsif ( $self->has_builder ) {
810 $value = $self->_call_builder($instance);
813 $value = $self->_coerce_and_verify( $value, $instance );
815 $self->set_initial_value($instance, $value);
817 if ( ref $value && $self->is_weak_ref ) {
818 $self->_weaken_value($instance);
823 if ( $self->should_auto_deref && ! $for_trigger ) {
825 my $type_constraint = $self->type_constraint;
827 if ($type_constraint->is_a_type_of('ArrayRef')) {
828 my $rv = $self->SUPER::get_value($instance);
829 return unless defined $rv;
830 return wantarray ? @{ $rv } : $rv;
832 elsif ($type_constraint->is_a_type_of('HashRef')) {
833 my $rv = $self->SUPER::get_value($instance);
834 return unless defined $rv;
835 return wantarray ? %{ $rv } : $rv;
838 $self->throw_error(message => "Can not auto de-reference the type constraint '" . $type_constraint->name . "'", object => $instance, type_constraint => $type_constraint);
844 return $self->SUPER::get_value($instance);
848 sub _inline_get_value {
850 my ($instance, $tc, $coercion, $message) = @_;
852 my $slot_access = $self->_inline_instance_get($instance);
853 $tc ||= '$type_constraint';
854 $coercion ||= '$type_coercion';
855 $message ||= '$type_message';
858 $self->_inline_check_lazy($instance, $tc, $coercion, $message),
859 $self->_inline_return_auto_deref($slot_access),
863 sub _inline_check_lazy {
865 my ($instance, $tc, $coercion, $message) = @_;
867 return unless $self->is_lazy;
869 my $slot_exists = $self->_inline_instance_has($instance);
872 'if (!' . $slot_exists . ') {',
873 $self->_inline_init_from_default($instance, '$default', $tc, $coercion, $message, 'lazy'),
878 sub _inline_init_from_default {
880 my ($instance, $default, $tc, $coercion, $message, $for_lazy) = @_;
882 if (!($self->has_default || $self->has_builder)) {
884 message => 'You cannot have a lazy attribute '
885 . '(' . $self->name . ') '
886 . 'without specifying a default value for it',
892 $self->_inline_generate_default($instance, $default),
893 # intentionally not using _inline_tc_code, since that can be overridden
894 # to do things like possibly only do member tc checks, which isn't
895 # appropriate for checking the result of a default
896 $self->has_type_constraint
897 ? ($self->_inline_check_coercion($default, $tc, $coercion, $for_lazy),
898 $self->_inline_check_constraint($default, $tc, $message, $for_lazy))
900 $self->_inline_init_slot($instance, $default),
901 $self->_inline_weaken_value($instance, $default),
905 sub _inline_generate_default {
907 my ($instance, $default) = @_;
909 if ($self->has_default) {
910 my $source = 'my ' . $default . ' = $attr_default';
911 $source .= '->(' . $instance . ')'
912 if $self->is_default_a_coderef;
913 return $source . ';';
915 elsif ($self->has_builder) {
916 my $builder = B::perlstring($self->builder);
917 my $builder_str = quotemeta($self->builder);
918 my $attr_name_str = quotemeta($self->name);
920 'my ' . $default . ';',
921 'if (my $builder = ' . $instance . '->can(' . $builder . ')) {',
922 $default . ' = ' . $instance . '->$builder;',
925 'my $class = ref(' . $instance . ') || ' . $instance . ';',
926 $self->_inline_throw_error(
927 '"$class does not support builder method '
928 . '\'' . $builder_str . '\' for attribute '
929 . '\'' . $attr_name_str . '\'"'
936 message => "Can't generate a default for " . $self->name
937 . " since no default or builder was specified"
942 sub _inline_init_slot {
944 my ($inv, $value) = @_;
946 if ($self->has_initializer) {
947 return '$attr->set_initial_value(' . $inv . ', ' . $value . ');';
950 return $self->_inline_instance_set($inv, $value) . ';';
954 sub _inline_return_auto_deref {
957 return 'return ' . $self->_auto_deref(@_) . ';';
962 my ($ref_value) = @_;
964 return $ref_value unless $self->should_auto_deref;
966 my $type_constraint = $self->type_constraint;
969 if ($type_constraint->is_a_type_of('ArrayRef')) {
972 elsif ($type_constraint->is_a_type_of('HashRef')) {
977 message => 'Can not auto de-reference the type constraint \''
978 . $type_constraint->name
980 type_constraint => $type_constraint,
985 . '? ' . $sigil . '{ (' . $ref_value . ') || return } '
986 . ': (' . $ref_value . ')';
989 ## installing accessors
991 sub accessor_metaclass { 'Moose::Meta::Method::Accessor' }
993 sub install_accessors {
995 $self->SUPER::install_accessors(@_);
996 $self->install_delegation if $self->has_handles;
1000 sub _check_associated_methods {
1003 @{ $self->associated_methods }
1004 || ($self->_is_metadata || '') eq 'bare'
1007 'Attribute (' . $self->name . ') of class '
1008 . $self->associated_class->name
1009 . ' has no associated methods'
1010 . ' (did you mean to provide an "is" argument?)'
1016 sub _process_accessors {
1018 my ($type, $accessor, $generate_as_inline_methods) = @_;
1020 $accessor = ( keys %$accessor )[0] if ( ref($accessor) || '' ) eq 'HASH';
1021 my $method = $self->associated_class->get_method($accessor);
1024 && $method->isa('Class::MOP::Method::Accessor')
1025 && $method->associated_attribute->name ne $self->name ) {
1027 my $other_attr_name = $method->associated_attribute->name;
1028 my $name = $self->name;
1031 "You are overwriting an accessor ($accessor) for the $other_attr_name attribute"
1032 . " with a new accessor method for the $name attribute" );
1037 && !$method->is_stub
1038 && !$method->isa('Class::MOP::Method::Accessor')
1039 && ( !$self->definition_context
1040 || $method->package_name eq $self->definition_context->{package} )
1044 "You are overwriting a locally defined method ($accessor) with "
1048 if ( !$self->associated_class->has_method($accessor)
1049 && $self->associated_class->has_package_symbol( '&' . $accessor ) ) {
1052 "You are overwriting a locally defined function ($accessor) with "
1056 $self->SUPER::_process_accessors(@_);
1059 sub remove_accessors {
1061 $self->SUPER::remove_accessors(@_);
1062 $self->remove_delegation if $self->has_handles;
1066 sub install_delegation {
1070 # Here we canonicalize the 'handles' option
1071 # this will sort out any details and always
1072 # return an hash of methods which we want
1073 # to delagate to, see that method for details
1074 my %handles = $self->_canonicalize_handles;
1077 # install the delegation ...
1078 my $associated_class = $self->associated_class;
1079 foreach my $handle (sort keys %handles) {
1080 my $method_to_call = $handles{$handle};
1081 my $class_name = $associated_class->name;
1082 my $name = "${class_name}::${handle}";
1084 if ( my $method = $associated_class->get_method($handle) ) {
1086 message => "You cannot overwrite a locally defined method ($handle) with a delegation",
1087 method_name => $handle
1088 ) unless $method->is_stub;
1092 # handles is not allowed to delegate
1093 # any of these methods, as they will
1094 # override the ones in your class, which
1095 # is almost certainly not what you want.
1097 # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something
1098 #cluck("Not delegating method '$handle' because it is a core method") and
1099 next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle);
1101 my $method = $self->_make_delegation_method($handle, $method_to_call);
1103 $self->associated_class->add_method($method->name, $method);
1104 $self->associate_method($method);
1108 sub remove_delegation {
1110 my %handles = $self->_canonicalize_handles;
1111 my $associated_class = $self->associated_class;
1112 foreach my $handle (keys %handles) {
1113 next unless any { $handle eq $_ }
1115 @{ $self->associated_methods };
1116 $self->associated_class->remove_method($handle);
1120 # private methods to help delegation ...
1122 sub _canonicalize_handles {
1124 my $handles = $self->handles;
1125 if (my $handle_type = ref($handles)) {
1126 if ($handle_type eq 'HASH') {
1129 elsif ($handle_type eq 'ARRAY') {
1130 return map { $_ => $_ } @{$handles};
1132 elsif ($handle_type eq 'Regexp') {
1133 ($self->has_type_constraint)
1134 || $self->throw_error(message => "Cannot delegate methods based on a Regexp without a type constraint (isa)", data => $handles);
1135 return map { ($_ => $_) }
1136 grep { /$handles/ } $self->_get_delegate_method_list;
1138 elsif ($handle_type eq 'CODE') {
1139 return $handles->($self, $self->_find_delegate_metaclass);
1141 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::DuckType')) {
1142 return map { $_ => $_ } @{ $handles->methods };
1144 elsif (blessed($handles) && $handles->isa('Moose::Meta::TypeConstraint::Role')) {
1145 $handles = $handles->role;
1148 $self->throw_error(message => "Unable to canonicalize the 'handles' option with $handles", data => $handles);
1152 load_class($handles);
1153 my $role_meta = Class::MOP::class_of($handles);
1155 (blessed $role_meta && $role_meta->isa('Moose::Meta::Role'))
1156 || $self->throw_error(message => "Unable to canonicalize the 'handles' option with $handles because its metaclass is not a Moose::Meta::Role", data => $handles);
1158 return map { $_ => $_ }
1160 grep { !$_->isa('Class::MOP::Method::Meta') } (
1161 $role_meta->_get_local_methods,
1162 $role_meta->get_required_method_list,
1166 sub _get_delegate_method_list {
1168 my $meta = $self->_find_delegate_metaclass;
1169 if ($meta->isa('Class::MOP::Class')) {
1170 return map { $_->name } # NOTE: !never! delegate &meta
1171 grep { $_->package_name ne 'Moose::Object' && !$_->isa('Class::MOP::Method::Meta') }
1172 $meta->get_all_methods;
1174 elsif ($meta->isa('Moose::Meta::Role')) {
1175 return $meta->get_method_list;
1178 $self->throw_error(message => "Unable to recognize the delegate metaclass '$meta'", data => $meta);
1182 sub _find_delegate_metaclass {
1184 if (my $class = $self->_isa_metadata) {
1185 unless ( is_class_loaded($class) ) {
1188 'The %s attribute is trying to delegate to a class which has not been loaded - %s',
1193 # we might be dealing with a non-Moose class,
1194 # and need to make our own metaclass. if there's
1195 # already a metaclass, it will be returned
1196 return Class::MOP::Class->initialize($class);
1198 elsif (my $role = $self->_does_metadata) {
1199 unless ( is_class_loaded($class) ) {
1202 'The %s attribute is trying to delegate to a role which has not been loaded - %s',
1208 return Class::MOP::class_of($role);
1211 $self->throw_error(message => "Cannot find delegate metaclass for attribute " . $self->name);
1215 sub delegation_metaclass { 'Moose::Meta::Method::Delegation' }
1217 sub _make_delegation_method {
1218 my ( $self, $handle_name, $method_to_call ) = @_;
1220 my @curried_arguments;
1222 ($method_to_call, @curried_arguments) = @$method_to_call
1223 if 'ARRAY' eq ref($method_to_call);
1225 return $self->delegation_metaclass->new(
1226 name => $handle_name,
1227 package_name => $self->associated_class->name,
1229 delegate_to_method => $method_to_call,
1230 curried_arguments => \@curried_arguments,
1234 sub _coerce_and_verify {
1237 my $instance = shift;
1239 return $val unless $self->has_type_constraint;
1241 $val = $self->type_constraint->coerce($val)
1242 if $self->should_coerce && $self->type_constraint->has_coercion;
1244 $self->verify_against_type_constraint($val, instance => $instance);
1249 sub verify_against_type_constraint {
1253 return 1 if !$self->has_type_constraint;
1255 my $type_constraint = $self->type_constraint;
1257 $type_constraint->check($val)
1258 || $self->throw_error("Attribute ("
1260 . ") does not pass the type constraint because: "
1261 . $type_constraint->get_message($val), data => $val, @_);
1264 package Moose::Meta::Attribute::Custom::Moose;
1265 sub register_implementation { 'Moose::Meta::Attribute' }
1269 # ABSTRACT: The Moose attribute metaclass
1277 This class is a subclass of L<Class::MOP::Attribute> that provides
1278 additional Moose-specific functionality.
1280 To really understand this class, you will need to start with the
1281 L<Class::MOP::Attribute> documentation. This class can be understood
1282 as a set of additional features on top of the basic feature provided
1283 by that parent class.
1287 C<Moose::Meta::Attribute> is a subclass of L<Class::MOP::Attribute>.
1291 Many of the documented below override methods in
1292 L<Class::MOP::Attribute> and add Moose specific features.
1298 =item B<< Moose::Meta::Attribute->new(%options) >>
1300 This method overrides the L<Class::MOP::Attribute> constructor.
1302 Many of the options below are described in more detail in the
1303 L<Moose::Manual::Attributes> document.
1305 It adds the following options to the constructor:
1309 =item * is => 'ro', 'rw', 'bare'
1311 This provides a shorthand for specifying the C<reader>, C<writer>, or
1312 C<accessor> names. If the attribute is read-only ('ro') then it will
1313 have a C<reader> method with the same attribute as the name.
1315 If it is read-write ('rw') then it will have an C<accessor> method
1316 with the same name. If you provide an explicit C<writer> for a
1317 read-write attribute, then you will have a C<reader> with the same
1318 name as the attribute, and a C<writer> with the name you provided.
1320 Use 'bare' when you are deliberately not installing any methods
1321 (accessor, reader, etc.) associated with this attribute; otherwise,
1322 Moose will issue a deprecation warning when this attribute is added to a
1325 =item * isa => $type
1327 This option accepts a type. The type can be a string, which should be
1328 a type name. If the type name is unknown, it is assumed to be a class
1331 This option can also accept a L<Moose::Meta::TypeConstraint> object.
1333 If you I<also> provide a C<does> option, then your C<isa> option must
1334 be a class name, and that class must do the role specified with
1337 =item * does => $role
1339 This is short-hand for saying that the attribute's type must be an
1340 object which does the named role.
1342 =item * coerce => $bool
1344 This option is only valid for objects with a type constraint
1345 (C<isa>) that defined a coercion. If this is true, then coercions will be applied whenever
1346 this attribute is set.
1348 You can make both this and the C<weak_ref> option true.
1350 =item * trigger => $sub
1352 This option accepts a subroutine reference, which will be called after
1353 the attribute is set.
1355 =item * required => $bool
1357 An attribute which is required must be provided to the constructor. An
1358 attribute which is required can also have a C<default> or C<builder>,
1359 which will satisfy its required-ness.
1361 A required attribute must have a C<default>, C<builder> or a
1362 non-C<undef> C<init_arg>
1364 =item * lazy => $bool
1366 A lazy attribute must have a C<default> or C<builder>. When an
1367 attribute is lazy, the default value will not be calculated until the
1370 =item * weak_ref => $bool
1372 If this is true, the attribute's value will be stored as a weak
1375 =item * auto_deref => $bool
1377 If this is true, then the reader will dereference the value when it is
1378 called. The attribute must have a type constraint which defines the
1379 attribute as an array or hash reference.
1381 =item * lazy_build => $bool
1383 Setting this to true makes the attribute lazy and provides a number of
1391 is equivalent to this:
1396 builder => '_build_size',
1397 clearer => 'clear_size',
1398 predicate => 'has_size',
1402 If your attribute name starts with an underscore (C<_>), then the clearer
1403 and predicate will as well:
1415 builder => '_build__size',
1416 clearer => '_clear_size',
1417 predicate => '_has_size',
1420 Note the doubled underscore in the builder name. Internally, Moose
1421 simply prepends the attribute name with "_build_" to come up with the
1424 =item * documentation
1426 An arbitrary string that can be retrieved later by calling C<<
1427 $attr->documentation >>.
1431 =item B<< $attr->clone(%options) >>
1433 This creates a new attribute based on attribute being cloned. You must
1434 supply a C<name> option to provide a new name for the attribute.
1436 The C<%options> can only specify options handled by
1437 L<Class::MOP::Attribute>.
1441 =head2 Value management
1445 =item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >>
1447 This method is used internally to initialize the attribute's slot in
1448 the object C<$instance>.
1450 This overrides the L<Class::MOP::Attribute> method to handle lazy
1451 attributes, weak references, and type constraints.
1457 eval { $point->meta->get_attribute('x')->set_value($point, 'forty-two') };
1462 I<Attribute (x) does not pass the type constraint (Int) with 'forty-two'>
1464 Before setting the value, a check is made on the type constraint of
1465 the attribute, if it has one, to see if the value passes it. If the
1466 value fails to pass, the set operation dies.
1468 Any coercion to convert values is done before checking the type constraint.
1470 To check a value against a type constraint before setting it, fetch the
1471 attribute instance using L<Class::MOP::Class/find_attribute_by_name>,
1472 fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint>
1473 and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::Basics::Company_Subtypes>
1478 =head2 Attribute Accessor generation
1482 =item B<< $attr->install_accessors >>
1484 This method overrides the parent to also install delegation methods.
1486 If, after installing all methods, the attribute object has no associated
1487 methods, it throws an error unless C<< is => 'bare' >> was passed to the
1488 attribute constructor. (Trying to add an attribute that has no associated
1489 methods is almost always an error.)
1491 =item B<< $attr->remove_accessors >>
1493 This method overrides the parent to also remove delegation methods.
1495 =item B<< $attr->inline_set($instance_var, $value_var) >>
1497 This method return a code snippet suitable for inlining the relevant
1498 operation. It expect strings containing variable names to be used in the
1499 inlining, like C<'$self'> or C<'$_[1]'>.
1501 =item B<< $attr->install_delegation >>
1503 This method adds its delegation methods to the attribute's associated
1504 class, if it has any to add.
1506 =item B<< $attr->remove_delegation >>
1508 This method remove its delegation methods from the attribute's
1511 =item B<< $attr->accessor_metaclass >>
1513 Returns the accessor metaclass name, which defaults to
1514 L<Moose::Meta::Method::Accessor>.
1516 =item B<< $attr->delegation_metaclass >>
1518 Returns the delegation metaclass name, which defaults to
1519 L<Moose::Meta::Method::Delegation>.
1523 =head2 Additional Moose features
1525 These methods are not found in the superclass. They support features
1530 =item B<< $attr->does($role) >>
1532 This indicates whether the I<attribute itself> does the given
1533 role. The role can be given as a full class name, or as a resolvable
1536 Note that this checks the attribute itself, not its type constraint,
1537 so it is checking the attribute's metaclass and any traits applied to
1540 =item B<< Moose::Meta::Class->interpolate_class_and_new($name, %options) >>
1542 This is an alternate constructor that handles the C<metaclass> and
1545 Effectively, this method is a factory that finds or creates the
1546 appropriate class for the given C<metaclass> and/or C<traits>.
1548 Once it has the appropriate class, it will call C<< $class->new($name,
1549 %options) >> on that class.
1551 =item B<< $attr->clone_and_inherit_options(%options) >>
1553 This method supports the C<has '+foo'> feature. It does various bits
1554 of processing on the supplied C<%options> before ultimately calling
1555 the C<clone> method.
1557 One of its main tasks is to make sure that the C<%options> provided
1558 does not include the options returned by the
1559 C<illegal_options_for_inheritance> method.
1561 =item B<< $attr->illegal_options_for_inheritance >>
1563 This returns a blacklist of options that can not be overridden in a
1564 subclass's attribute definition.
1566 This exists to allow a custom metaclass to change or add to the list
1567 of options which can not be changed.
1569 =item B<< $attr->type_constraint >>
1571 Returns the L<Moose::Meta::TypeConstraint> object for this attribute,
1574 =item B<< $attr->has_type_constraint >>
1576 Returns true if this attribute has a type constraint.
1578 =item B<< $attr->verify_against_type_constraint($value) >>
1580 Given a value, this method returns true if the value is valid for the
1581 attribute's type constraint. If the value is not valid, it throws an
1584 =item B<< $attr->handles >>
1586 This returns the value of the C<handles> option passed to the
1589 =item B<< $attr->has_handles >>
1591 Returns true if this attribute performs delegation.
1593 =item B<< $attr->is_weak_ref >>
1595 Returns true if this attribute stores its value as a weak reference.
1597 =item B<< $attr->is_required >>
1599 Returns true if this attribute is required to have a value.
1601 =item B<< $attr->is_lazy >>
1603 Returns true if this attribute is lazy.
1605 =item B<< $attr->is_lazy_build >>
1607 Returns true if the C<lazy_build> option was true when passed to the
1610 =item B<< $attr->should_coerce >>
1612 Returns true if the C<coerce> option passed to the constructor was
1615 =item B<< $attr->should_auto_deref >>
1617 Returns true if the C<auto_deref> option passed to the constructor was
1620 =item B<< $attr->trigger >>
1622 This is the subroutine reference that was in the C<trigger> option
1623 passed to the constructor, if any.
1625 =item B<< $attr->has_trigger >>
1627 Returns true if this attribute has a trigger set.
1629 =item B<< $attr->documentation >>
1631 Returns the value that was in the C<documentation> option passed to
1632 the constructor, if any.
1634 =item B<< $attr->has_documentation >>
1636 Returns true if this attribute has any documentation.
1638 =item B<< $attr->applied_traits >>
1640 This returns an array reference of all the traits which were applied
1641 to this attribute. If none were applied, this returns C<undef>.
1643 =item B<< $attr->has_applied_traits >>
1645 Returns true if this attribute has any traits applied.
1651 See L<Moose/BUGS> for details on reporting bugs.