1 package Mouse::Meta::Attribute;
8 use Mouse::Meta::TypeConstraint;
9 use Mouse::Meta::Method::Accessor;
12 my ($class, $name, %options) = @_;
14 $options{name} = $name;
16 $options{init_arg} = $name
17 unless exists $options{init_arg};
21 bless \%options, $class;
24 sub name { $_[0]->{name} }
25 sub associated_class { $_[0]->{associated_class} }
26 sub _is_metadata { $_[0]->{is} }
27 sub is_required { $_[0]->{required} }
28 sub default { $_[0]->{default} }
29 sub is_lazy { $_[0]->{lazy} }
30 sub is_lazy_build { $_[0]->{lazy_build} }
31 sub predicate { $_[0]->{predicate} }
32 sub clearer { $_[0]->{clearer} }
33 sub handles { $_[0]->{handles} }
34 sub is_weak_ref { $_[0]->{weak_ref} }
35 sub init_arg { $_[0]->{init_arg} }
36 sub type_constraint { $_[0]->{type_constraint} }
37 sub find_type_constraint {
38 Carp::carp("This method was deprecated");
39 $_[0]->type_constraint();
41 sub trigger { $_[0]->{trigger} }
42 sub builder { $_[0]->{builder} }
43 sub should_auto_deref { $_[0]->{auto_deref} }
44 sub should_coerce { $_[0]->{should_coerce} }
46 sub has_default { exists $_[0]->{default} }
47 sub has_predicate { exists $_[0]->{predicate} }
48 sub has_clearer { exists $_[0]->{clearer} }
49 sub has_handles { exists $_[0]->{handles} }
50 sub has_type_constraint { exists $_[0]->{type_constraint} }
51 sub has_trigger { exists $_[0]->{trigger} }
52 sub has_builder { exists $_[0]->{builder} }
55 $_[0]->{_create_args} = $_[1] if @_ > 1;
61 my $name = $self->name;
62 my $key = "'" . $name . "'";
66 sub generate_predicate {
67 my $attribute = shift;
68 my $key = $attribute->inlined_name;
70 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
72 my $sub = eval $predicate;
77 sub generate_clearer {
78 my $attribute = shift;
79 my $key = $attribute->inlined_name;
81 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
83 my $sub = eval $clearer;
88 sub generate_handles {
89 my $attribute = shift;
90 my $reader = $attribute->name;
91 my %handles = $attribute->_canonicalize_handles($attribute->handles);
95 for my $local_method (keys %handles) {
96 my $remote_method = $handles{$local_method};
100 $self->'.$reader.'->'.$remote_method.'(@_)
103 $method_map{$local_method} = eval $method;
111 my ($self, $class, $name, %args) = @_;
114 $args{associated_class} = $class;
116 %args = $self->canonicalize_args($name, %args);
117 $self->validate_args($name, \%args);
119 $args{should_coerce} = delete $args{coerce}
120 if exists $args{coerce};
122 if (exists $args{isa}) {
123 confess "Got isa => $args{isa}, but Mouse does not yet support parameterized types for containers other than ArrayRef and HashRef (rt.cpan.org #39795)"
124 if $args{isa} =~ /^([^\[]+)\[.+\]$/ &&
130 my $type_constraint = delete $args{isa};
131 $args{type_constraint}= Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($type_constraint);
134 my $attribute = $self->new($name, %args);
136 $attribute->_create_args(\%args);
138 $class->add_attribute($attribute);
140 # install an accessor
141 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
142 my $code = Mouse::Meta::Method::Accessor->generate_accessor_method_inline(
145 $class->add_method($name => $code);
148 for my $method (qw/predicate clearer/) {
149 my $predicate = "has_$method";
150 if ($attribute->$predicate) {
151 my $generator = "generate_$method";
152 my $coderef = $attribute->$generator;
153 $class->add_method($attribute->$method => $coderef);
157 if ($attribute->has_handles) {
158 my $method_map = $attribute->generate_handles;
159 for my $method_name (keys %$method_map) {
160 $class->add_method($method_name => $method_map->{$method_name});
167 sub canonicalize_args {
172 if ($args{lazy_build}) {
175 $args{builder} = "_build_${name}"
176 if !exists($args{builder});
178 $args{clearer} = "_clear${name}" if !exists($args{clearer});
179 $args{predicate} = "_has${name}" if !exists($args{predicate});
182 $args{clearer} = "clear_${name}" if !exists($args{clearer});
183 $args{predicate} = "has_${name}" if !exists($args{predicate});
195 confess "You can not use lazy_build and default for the same attribute ($name)"
196 if $args->{lazy_build} && exists $args->{default};
198 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
200 && !exists($args->{default})
201 && !exists($args->{builder});
203 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
204 if ref($args->{default})
205 && ref($args->{default}) ne 'CODE';
207 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
208 if $args->{auto_deref} && !exists($args->{isa});
210 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
211 if $args->{auto_deref}
212 && $args->{isa} ne 'ArrayRef'
213 && $args->{isa} ne 'HashRef';
215 if ($args->{trigger}) {
216 if (ref($args->{trigger}) eq 'HASH') {
217 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
220 confess "Trigger must be a CODE ref on attribute ($name)"
221 if ref($args->{trigger}) ne 'CODE';
227 sub verify_against_type_constraint {
228 return 1 unless $_[0]->{type_constraint};
231 return 1 if $_[0]->{type_constraint}->check($_);
234 $self->verify_type_constraint_error($self->name, $_, $self->{type_constraint});
237 sub verify_type_constraint_error {
238 my($self, $name, $value, $type) = @_;
239 Carp::confess("Attribute ($name) does not pass the type constraint because: " . $type->get_message($value));
242 sub coerce_constraint { ## my($self, $value) = @_;
243 my $type = $_[0]->{type_constraint}
245 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->type_constraint, $_[1]);
248 sub _canonicalize_handles {
252 if (ref($handles) eq 'HASH') {
255 elsif (ref($handles) eq 'ARRAY') {
256 return map { $_ => $_ } @$handles;
259 confess "Unable to canonicalize the 'handles' option with $handles";
267 my %args = ($self->get_parent_args($class, $name), @_);
269 $self->create($class, $name, %args);
272 sub get_parent_args {
277 for my $super ($class->linearized_isa) {
278 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
280 return %{ $super_attr->_create_args };
283 confess "Could not find an attribute by the name of '$name' to inherit from";
292 Mouse::Meta::Attribute - attribute metaclass
296 =head2 new %args -> Mouse::Meta::Attribute
298 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
300 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
302 Creates a new attribute in OwnerClass. Accessors and helper methods are
303 installed. Some error checking is done.
305 =head2 name -> AttributeName
307 =head2 associated_class -> OwnerClass
309 =head2 is_required -> Bool
311 =head2 default -> Item
313 =head2 has_default -> Bool
315 =head2 is_lazy -> Bool
317 =head2 predicate -> MethodName | Undef
319 =head2 has_predicate -> Bool
321 =head2 clearer -> MethodName | Undef
323 =head2 has_clearer -> Bool
325 =head2 handles -> { LocalName => RemoteName }
327 =head2 has_handles -> Bool
329 =head2 is_weak_ref -> Bool
331 =head2 init_arg -> Str
333 =head2 type_constraint -> Str
335 =head2 has_type_constraint -> Bool
337 =head2 trigger => CODE | Undef
339 =head2 has_trigger -> Bool
341 =head2 builder => MethodName | Undef
343 =head2 has_builder -> Bool
345 =head2 is_lazy_build => Bool
347 =head2 should_auto_deref -> Bool
349 Informational methods.
351 =head2 generate_accessor -> CODE
353 Creates a new code reference for the attribute's accessor.
355 =head2 generate_predicate -> CODE
357 Creates a new code reference for the attribute's predicate.
359 =head2 generate_clearer -> CODE
361 Creates a new code reference for the attribute's clearer.
363 =head2 generate_handles -> { MethodName => CODE }
365 Creates a new code reference for each of the attribute's handles methods.
367 =head2 verify_against_type_constraint Item -> 1 | ERROR
369 Checks that the given value passes this attribute's type constraint. Returns 1
370 on success, otherwise C<confess>es.
372 =head2 canonicalize_args Name, %args -> %args
374 Canonicalizes some arguments to create. In particular, C<lazy_build> is
375 canonicalized into C<lazy>, C<builder>, etc.
377 =head2 validate_args Name, \%args -> 1 | ERROR
379 Checks that the arguments to create the attribute (ie those specified by
382 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
384 Creates a new attribute in OwnerClass, inheriting options from parent classes.
385 Accessors and helper methods are installed. Some error checking is done.
387 =head2 get_parent_args OwnerClass, AttributeName -> Hash
389 Returns the options that the parent class of C<OwnerClass> used for attribute