1 package Mouse::Meta::Attribute;
6 use Scalar::Util qw(weaken);
10 use Mouse::Meta::TypeConstraint;
11 use Mouse::Meta::Method::Accessor;
16 my %args = (@_ == 1) ? %{$_[0]} : @_;
20 # XXX: for backward compatibility (with method modifiers)
21 if($class->can('canonicalize_args') != \&canonicalize_args){
22 %args = $class->canonicalize_args($name, %args);
30 my $args = $class->BUILDARGS(@_);
32 my $name = $args->{name};
34 # taken from Class::MOP::Attribute::new
37 or $class->throw_error('You must provide a name for the attribute');
39 if(!exists $args->{init_arg}){
40 $args->{init_arg} = $name;
43 # 'required' requires eigher 'init_arg', 'builder', or 'default'
44 my $can_be_required = defined( $args->{init_arg} );
46 if(exists $args->{builder}){
47 $class->throw_error('builder must be a defined scalar value which is a method name')
48 if ref $args->{builder} || !(defined $args->{builder});
52 elsif(exists $args->{default}){
53 if(ref $args->{default} && ref($args->{default}) ne 'CODE'){
54 $class->throw_error("References are not allowed as default values, you must "
55 . "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])");
60 if( $args->{required} && !$can_be_required ) {
61 $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg");
64 # taken from Mouse::Meta::Attribute->new and _process_args->
66 if(exists $args->{is}){
70 $args->{reader} ||= $name;
73 if(exists $args->{writer}){
74 $args->{reader} ||= $name;
77 $args->{accessor} ||= $name;
81 # do nothing, but don't complain (later) about missing methods
84 $is = 'undef' if !defined $is;
85 $class->throw_error("I do not understand this option (is => $is) on attribute ($name)");
90 if(exists $args->{isa}){
91 $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($args->{isa});
93 elsif(exists $args->{does}){
94 $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($args->{does});
96 $tc = $args->{type_constraint};
100 || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)");
103 && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)");
106 if ($args->{lazy_build}) {
107 exists($args->{default})
108 && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)");
111 $args->{builder} ||= "_build_${name}";
113 $args->{clearer} ||= "_clear${name}";
114 $args->{predicate} ||= "_has${name}";
117 $args->{clearer} ||= "clear_${name}";
118 $args->{predicate} ||= "has_${name}";
122 if ($args->{auto_deref}) {
124 || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)");
126 ( $tc->is_a_type_of('ArrayRef') || $tc->is_a_type_of('HashRef') )
127 || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)");
130 if (exists $args->{trigger}) {
131 ('CODE' eq ref $args->{trigger})
132 || $class->throw_error("Trigger must be a CODE ref on attribute ($name)");
136 (exists $args->{default} || defined $args->{builder})
137 || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it");
140 my $instance = bless $args, $class;
143 if($class ne __PACKAGE__){
144 $class->meta->_initialize_instance($instance, $args);
147 # XXX: there is no fast way to check attribute validity
151 # Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad");
158 my ($self, $role_name) = @_;
159 my $meta = Mouse::Meta::Class->initialize(ref($self) || $self);
162 || $meta->throw_error("You must supply a role name to does()");
164 return $meta->does_role($role_name);
169 sub name { $_[0]->{name} }
170 sub associated_class { $_[0]->{associated_class} }
172 sub accessor { $_[0]->{accessor} }
173 sub reader { $_[0]->{reader} }
174 sub writer { $_[0]->{writer} }
175 sub predicate { $_[0]->{predicate} }
176 sub clearer { $_[0]->{clearer} }
177 sub handles { $_[0]->{handles} }
179 sub _is_metadata { $_[0]->{is} }
180 sub is_required { $_[0]->{required} }
181 sub default { $_[0]->{default} }
182 sub is_lazy { $_[0]->{lazy} }
183 sub is_lazy_build { $_[0]->{lazy_build} }
184 sub is_weak_ref { $_[0]->{weak_ref} }
185 sub init_arg { $_[0]->{init_arg} }
186 sub type_constraint { $_[0]->{type_constraint} }
188 sub trigger { $_[0]->{trigger} }
189 sub builder { $_[0]->{builder} }
190 sub should_auto_deref { $_[0]->{auto_deref} }
191 sub should_coerce { $_[0]->{coerce} }
193 sub get_read_method { $_[0]->{reader} || $_[0]->{accessor} }
194 sub get_write_method { $_[0]->{writer} || $_[0]->{accessor} }
198 sub has_accessor { exists $_[0]->{accessor} }
199 sub has_reader { exists $_[0]->{reader} }
200 sub has_writer { exists $_[0]->{writer} }
201 sub has_predicate { exists $_[0]->{predicate} }
202 sub has_clearer { exists $_[0]->{clearer} }
203 sub has_handles { exists $_[0]->{handles} }
205 sub has_default { exists $_[0]->{default} }
206 sub has_type_constraint { exists $_[0]->{type_constraint} }
207 sub has_trigger { exists $_[0]->{trigger} }
208 sub has_builder { exists $_[0]->{builder} }
210 sub has_read_method { exists $_[0]->{reader} || exists $_[0]->{accessor} }
211 sub has_write_method { exists $_[0]->{writer} || exists $_[0]->{accessor} }
214 $_[0]->{_create_args} = $_[1] if @_ > 1;
215 $_[0]->{_create_args}
218 sub accessor_metaclass { 'Mouse::Meta::Method::Accessor' }
220 sub interpolate_class_and_new{
221 my($class, $name, $args) = @_;
223 if(my $metaclass = delete $args->{metaclass}){
224 $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass );
228 if(my $traits_ref = delete $args->{traits}){
230 for (my $i = 0; $i < @{$traits_ref}; $i++) {
231 my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1);
233 next if $class->does($trait);
235 push @traits, $trait;
238 push @traits, $traits_ref->[++$i]
239 if ref($traits_ref->[$i+1]);
243 $class = Mouse::Meta::Class->create_anon_class(
244 superclasses => [ $class ],
249 $args->{traits} = \@traits;
253 return $class->new($name, $args);
256 sub canonicalize_args{
257 my ($self, $name, %args) = @_;
259 Carp::cluck("$self->canonicalize_args has been deprecated."
260 . "Use \$self->BUILDARGS instead.");
266 my ($self, $class, $name, %args) = @_;
268 Carp::cluck("$self->create has been deprecated."
269 . "Use \$meta->add_attribute and \$attr->install_accessors instead.");
275 sub verify_against_type_constraint {
276 my ($self, $value) = @_;
277 my $tc = $self->type_constraint;
281 return 1 if $tc->check($value);
283 $self->verify_type_constraint_error($self->name, $value, $tc);
286 sub verify_type_constraint_error {
287 my($self, $name, $value, $type) = @_;
288 $self->throw_error("Attribute ($name) does not pass the type constraint because: " . $type->get_message($value));
291 sub coerce_constraint { ## my($self, $value) = @_;
292 my $type = $_[0]->{type_constraint}
294 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->type_constraint, $_[1]);
297 sub _canonicalize_handles {
301 if (ref($handles) eq 'HASH') {
304 elsif (ref($handles) eq 'ARRAY') {
305 return map { $_ => $_ } @$handles;
308 $self->throw_error("Unable to canonicalize the 'handles' option with $handles");
312 sub clone_and_inherit_options{
316 return ref($self)->new($name, %{$self}, @_ == 1 ? %{$_[0]} : @_);
323 my %args = ($self->get_parent_args($class, $name), @_);
325 Carp::cluck("$self->clone_parent has been deprecated."
326 . "Use \$meta->add_attribute and \$attr->install_accessors instead.");
329 $self->create($class, $name, %args);
332 sub get_parent_args {
337 for my $super ($class->linearized_isa) {
338 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
340 return %{ $super_attr->_create_args };
343 $self->throw_error("Could not find an attribute by the name of '$name' to inherit from");
346 sub install_accessors{
349 my $metaclass = $attribute->{associated_class};
350 my $generator_class = $attribute->accessor_metaclass;
352 foreach my $type(qw(accessor reader writer predicate clearer handles)){
353 if(exists $attribute->{$type}){
354 my $installer = '_install_' . $type;
355 $generator_class->$installer($attribute, $attribute->{$type}, $metaclass);
356 $attribute->{associated_methods}++;
360 if($attribute->can('create') != \&create){
361 $attribute->create($metaclass, $attribute->name, %{$attribute});
370 my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class';
371 $metaclass->throw_error(@_, depth => 1);
380 Mouse::Meta::Attribute - attribute metaclass
384 =head2 new %args -> Mouse::Meta::Attribute
386 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
388 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
390 Creates a new attribute in OwnerClass. Accessors and helper methods are
391 installed. Some error checking is done.
393 =head2 name -> AttributeName
395 =head2 associated_class -> OwnerClass
397 =head2 is_required -> Bool
399 =head2 default -> Item
401 =head2 has_default -> Bool
403 =head2 is_lazy -> Bool
405 =head2 predicate -> MethodName | Undef
407 =head2 has_predicate -> Bool
409 =head2 clearer -> MethodName | Undef
411 =head2 has_clearer -> Bool
413 =head2 handles -> { LocalName => RemoteName }
415 =head2 has_handles -> Bool
417 =head2 is_weak_ref -> Bool
419 =head2 init_arg -> Str
421 =head2 type_constraint -> Str
423 =head2 has_type_constraint -> Bool
425 =head2 trigger => CODE | Undef
427 =head2 has_trigger -> Bool
429 =head2 builder => MethodName | Undef
431 =head2 has_builder -> Bool
433 =head2 is_lazy_build => Bool
435 =head2 should_auto_deref -> Bool
437 Informational methods.
439 =head2 verify_against_type_constraint Item -> 1 | ERROR
441 Checks that the given value passes this attribute's type constraint. Returns 1
442 on success, otherwise C<confess>es.
444 =head2 canonicalize_args Name, %args -> %args
446 Canonicalizes some arguments to create. In particular, C<lazy_build> is
447 canonicalized into C<lazy>, C<builder>, etc.
449 =head2 validate_args Name, \%args -> 1 | ERROR
451 Checks that the arguments to create the attribute (ie those specified by
454 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
456 Creates a new attribute in OwnerClass, inheriting options from parent classes.
457 Accessors and helper methods are installed. Some error checking is done.
459 =head2 get_parent_args OwnerClass, AttributeName -> Hash
461 Returns the options that the parent class of C<OwnerClass> used for attribute