1 package Mouse::Meta::Attribute;
8 use Mouse::Meta::TypeConstraint;
11 my ($class, $name, %options) = @_;
13 $options{name} = $name;
15 $options{init_arg} = $name
16 unless exists $options{init_arg};
20 bless \%options, $class;
23 sub name { $_[0]->{name} }
24 sub associated_class { $_[0]->{associated_class} }
25 sub _is_metadata { $_[0]->{is} }
26 sub is_required { $_[0]->{required} }
27 sub default { $_[0]->{default} }
28 sub is_lazy { $_[0]->{lazy} }
29 sub is_lazy_build { $_[0]->{lazy_build} }
30 sub predicate { $_[0]->{predicate} }
31 sub clearer { $_[0]->{clearer} }
32 sub handles { $_[0]->{handles} }
33 sub is_weak_ref { $_[0]->{weak_ref} }
34 sub init_arg { $_[0]->{init_arg} }
35 sub type_constraint { $_[0]->{type_constraint} }
36 sub find_type_constraint {
37 Carp::carp("This method was deprecated");
38 $_[0]->type_constraint();
40 sub trigger { $_[0]->{trigger} }
41 sub builder { $_[0]->{builder} }
42 sub should_auto_deref { $_[0]->{auto_deref} }
43 sub should_coerce { $_[0]->{should_coerce} }
45 sub has_default { exists $_[0]->{default} }
46 sub has_predicate { exists $_[0]->{predicate} }
47 sub has_clearer { exists $_[0]->{clearer} }
48 sub has_handles { exists $_[0]->{handles} }
49 sub has_type_constraint { exists $_[0]->{type_constraint} }
50 sub has_trigger { exists $_[0]->{trigger} }
51 sub has_builder { exists $_[0]->{builder} }
54 $_[0]->{_create_args} = $_[1] if @_ > 1;
60 return sprintf '"%s"', quotemeta $self->name;
63 sub _generate_accessor{
66 my $name = $attribute->name;
67 my $default = $attribute->default;
68 my $constraint = $attribute->type_constraint;
69 my $builder = $attribute->builder;
70 my $trigger = $attribute->trigger;
71 my $is_weak = $attribute->is_weak_ref;
72 my $should_deref = $attribute->should_auto_deref;
73 my $should_coerce = $attribute->should_coerce;
75 my $compiled_type_constraint = $constraint ? $constraint->{_compiled_type_constraint} : undef;
78 my $key = $attribute->_inlined_name;
81 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
83 if ($attribute->_is_metadata eq 'rw') {
85 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
86 'if (scalar(@_) >= 2) {' . "\n";
94 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
95 'my $val = Mouse::Util::TypeConstraints->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{type_constraint}, '.$value.');';
98 if ($compiled_type_constraint) {
101 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
102 'unless ($compiled_type_constraint->('.$value.')) {
103 $attribute->verify_type_constraint_error($name, '.$value.', $attribute->{type_constraint});
108 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
109 'unless ($constraint->check('.$value.')) {
110 $attribute->verify_type_constraint_error($name, '.$value.', $attribute->{type_constraint});
115 # if there's nothing left to do for the attribute we can return during
117 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
119 $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
122 $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
126 $accessor .= '$trigger->('.$self.', '.$value.');' . "\n";
132 $accessor .= 'Carp::confess("Cannot assign a value to a read-only accessor") if scalar(@_) >= 2;' . "\n";
135 if ($attribute->is_lazy) {
136 $accessor .= $self.'->{'.$key.'} = ';
138 $accessor .= $attribute->has_builder
140 : ref($default) eq 'CODE'
141 ? '$default->('.$self.')'
143 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
147 if (ref($constraint) && $constraint->name =~ '^ArrayRef\b') {
148 $accessor .= 'if (wantarray) {
149 return @{ '.$self.'->{'.$key.'} || [] };
153 $accessor .= 'if (wantarray) {
154 return %{ '.$self.'->{'.$key.'} || {} };
159 $accessor .= 'return '.$self.'->{'.$key.'};
162 my $sub = eval $accessor;
163 Carp::confess($@) if $@;
168 sub _generate_predicate {
169 my $attribute = shift;
170 my $key = $attribute->_inlined_name;
172 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
174 my $sub = eval $predicate;
179 sub _generate_clearer {
180 my $attribute = shift;
181 my $key = $attribute->_inlined_name;
183 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
185 my $sub = eval $clearer;
190 sub _generate_handles {
191 my $attribute = shift;
192 my $reader = $attribute->name;
193 my %handles = $attribute->_canonicalize_handles($attribute->handles);
197 for my $local_method (keys %handles) {
198 my $remote_method = $handles{$local_method};
202 $self->'.$reader.'->'.$remote_method.'(@_)
205 $method_map{$local_method} = eval $method;
213 my ($self, $class, $name, %args) = @_;
216 $args{associated_class} = $class;
218 %args = $self->canonicalize_args($name, %args);
219 $self->validate_args($name, \%args);
221 $args{should_coerce} = delete $args{coerce}
222 if exists $args{coerce};
224 if (exists $args{isa}) {
225 confess "Got isa => $args{isa}, but Mouse does not yet support parameterized types for containers other than ArrayRef and HashRef (rt.cpan.org #39795)"
226 if $args{isa} =~ /^([^\[]+)\[.+\]$/ &&
232 my $type_constraint = delete $args{isa};
233 $args{type_constraint}= Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($type_constraint);
236 my $attribute = $self->new($name, %args);
238 $attribute->_create_args(\%args);
240 $class->add_attribute($attribute);
242 # install an accessor
243 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
244 my $code = $attribute->_generate_accessor();
245 $class->add_method($name => $code);
248 for my $method (qw/predicate clearer/) {
249 my $predicate = "has_$method";
250 if ($attribute->$predicate) {
251 my $generator = "_generate_$method";
252 my $coderef = $attribute->$generator;
253 $class->add_method($attribute->$method => $coderef);
257 if ($attribute->has_handles) {
258 my $method_map = $attribute->_generate_handles;
259 for my $method_name (keys %$method_map) {
260 $class->add_method($method_name => $method_map->{$method_name});
267 sub canonicalize_args {
272 if ($args{lazy_build}) {
275 $args{builder} = "_build_${name}"
276 if !exists($args{builder});
278 $args{clearer} = "_clear${name}" if !exists($args{clearer});
279 $args{predicate} = "_has${name}" if !exists($args{predicate});
282 $args{clearer} = "clear_${name}" if !exists($args{clearer});
283 $args{predicate} = "has_${name}" if !exists($args{predicate});
295 confess "You can not use lazy_build and default for the same attribute ($name)"
296 if $args->{lazy_build} && exists $args->{default};
298 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
300 && !exists($args->{default})
301 && !exists($args->{builder});
303 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
304 if ref($args->{default})
305 && ref($args->{default}) ne 'CODE';
307 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
308 if $args->{auto_deref} && !exists($args->{isa});
310 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
311 if $args->{auto_deref}
312 && $args->{isa} !~ /^(?:ArrayRef|HashRef)(?:\[.*\])?$/;
314 if ($args->{trigger}) {
315 if (ref($args->{trigger}) eq 'HASH') {
316 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
319 confess "Trigger must be a CODE ref on attribute ($name)"
320 if ref($args->{trigger}) ne 'CODE';
326 sub verify_against_type_constraint {
327 my ($self, $value) = @_;
328 my $tc = $self->type_constraint;
332 return 1 if $tc->check($value);
334 $self->verify_type_constraint_error($self->name, $value, $tc);
337 sub verify_type_constraint_error {
338 my($self, $name, $value, $type) = @_;
339 Carp::confess("Attribute ($name) does not pass the type constraint because: " . $type->get_message($value));
342 sub coerce_constraint { ## my($self, $value) = @_;
343 my $type = $_[0]->{type_constraint}
345 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->type_constraint, $_[1]);
348 sub _canonicalize_handles {
352 if (ref($handles) eq 'HASH') {
355 elsif (ref($handles) eq 'ARRAY') {
356 return map { $_ => $_ } @$handles;
359 confess "Unable to canonicalize the 'handles' option with $handles";
367 my %args = ($self->get_parent_args($class, $name), @_);
369 $self->create($class, $name, %args);
372 sub get_parent_args {
377 for my $super ($class->linearized_isa) {
378 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
380 return %{ $super_attr->_create_args };
383 confess "Could not find an attribute by the name of '$name' to inherit from";
392 Mouse::Meta::Attribute - attribute metaclass
396 =head2 new %args -> Mouse::Meta::Attribute
398 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
400 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
402 Creates a new attribute in OwnerClass. Accessors and helper methods are
403 installed. Some error checking is done.
405 =head2 name -> AttributeName
407 =head2 associated_class -> OwnerClass
409 =head2 is_required -> Bool
411 =head2 default -> Item
413 =head2 has_default -> Bool
415 =head2 is_lazy -> Bool
417 =head2 predicate -> MethodName | Undef
419 =head2 has_predicate -> Bool
421 =head2 clearer -> MethodName | Undef
423 =head2 has_clearer -> Bool
425 =head2 handles -> { LocalName => RemoteName }
427 =head2 has_handles -> Bool
429 =head2 is_weak_ref -> Bool
431 =head2 init_arg -> Str
433 =head2 type_constraint -> Str
435 =head2 has_type_constraint -> Bool
437 =head2 trigger => CODE | Undef
439 =head2 has_trigger -> Bool
441 =head2 builder => MethodName | Undef
443 =head2 has_builder -> Bool
445 =head2 is_lazy_build => Bool
447 =head2 should_auto_deref -> Bool
449 Informational methods.
451 =head2 verify_against_type_constraint Item -> 1 | ERROR
453 Checks that the given value passes this attribute's type constraint. Returns 1
454 on success, otherwise C<confess>es.
456 =head2 canonicalize_args Name, %args -> %args
458 Canonicalizes some arguments to create. In particular, C<lazy_build> is
459 canonicalized into C<lazy>, C<builder>, etc.
461 =head2 validate_args Name, \%args -> 1 | ERROR
463 Checks that the arguments to create the attribute (ie those specified by
466 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
468 Creates a new attribute in OwnerClass, inheriting options from parent classes.
469 Accessors and helper methods are installed. Some error checking is done.
471 =head2 get_parent_args OwnerClass, AttributeName -> Hash
473 Returns the options that the parent class of C<OwnerClass> used for attribute