2 package Mouse::Meta::Attribute;
14 my $name = $args{name};
16 $args{init_arg} = $name
17 unless exists $args{init_arg};
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 trigger { $_[0]->{trigger} }
38 sub builder { $_[0]->{builder} }
39 sub should_auto_deref { $_[0]->{auto_deref} }
40 sub should_coerce { $_[0]->{should_coerce} }
42 sub has_default { exists $_[0]->{default} }
43 sub has_predicate { exists $_[0]->{predicate} }
44 sub has_clearer { exists $_[0]->{clearer} }
45 sub has_handles { exists $_[0]->{handles} }
46 sub has_type_constraint { exists $_[0]->{type_constraint} }
47 sub has_trigger { exists $_[0]->{trigger} }
48 sub has_builder { exists $_[0]->{builder} }
50 sub find_type_constraint { $_[0]->{find_type_constraint} }
51 sub type_constraint_as_string {
52 ref($_[0]->{type_constraint}) eq 'ARRAY' ? join '|', @{ $_[0]->{type_constraint} } : $_[0]->{type_constraint}
56 $_[0]->{_create_args} = $_[1] if @_ > 1;
62 my $name = $self->name;
63 my $key = "'" . $name . "'";
67 sub generate_accessor {
68 my $attribute = shift;
70 my $name = $attribute->name;
71 my $default = $attribute->default;
72 my $type = $attribute->type_constraint_as_string;
73 my $constraint = $attribute->find_type_constraint;
74 my $builder = $attribute->builder;
75 my $trigger = $attribute->trigger;
76 my $is_weak = $attribute->is_weak_ref;
77 my $should_deref = $attribute->should_auto_deref;
78 my $should_coerce = $attribute->should_coerce;
81 my $key = $attribute->inlined_name;
83 my $accessor = "sub {\n";
84 if ($attribute->_is_metadata eq 'rw') {
85 $accessor .= 'if (scalar(@_) >= 2) {' . "\n";
90 $accessor .= 'local $_ = '.$self.'->{'.$key.'} = ';
92 $accessor .= '$attribute->coerce_constraint('.$value.');';
94 $accessor .= $value.';';
97 unless ($constraint->()) {
98 my $display = defined($_) ? overload::StrVal($_) : "undef";
99 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
103 # if there's nothing left to do for the attribute we can return during
105 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
108 $accessor .= 'Mouse::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
112 $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
118 $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
121 if ($attribute->is_lazy) {
122 $accessor .= $self.'->{'.$key.'} = ';
124 $accessor .= $attribute->has_builder
126 : ref($default) eq 'CODE'
127 ? '$default->('.$self.')'
129 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
133 my $type_constraint = $attribute->type_constraint;
134 if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
135 $accessor .= 'if (wantarray) {
136 return @{ '.$self.'->{'.$key.'} || [] };
140 $accessor .= 'if (wantarray) {
141 return %{ '.$self.'->{'.$key.'} || {} };
146 $accessor .= 'return '.$self.'->{'.$key.'};
149 my $sub = eval $accessor;
154 sub generate_predicate {
155 my $attribute = shift;
156 my $key = $attribute->inlined_name;
158 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
160 my $sub = eval $predicate;
165 sub generate_clearer {
166 my $attribute = shift;
167 my $key = $attribute->inlined_name;
169 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
171 my $sub = eval $clearer;
176 sub generate_handles {
177 my $attribute = shift;
178 my $reader = $attribute->name;
179 my %handles = $attribute->_canonicalize_handles($attribute->handles);
183 for my $local_method (keys %handles) {
184 my $remote_method = $handles{$local_method};
188 $self->$reader->$remote_method(@_)
191 $method_map{$local_method} = eval $method;
199 my ($self, $class, $name, %args) = @_;
202 $args{associated_class} = $class;
204 %args = $self->canonicalize_args($name, %args);
205 $self->validate_args($name, \%args);
207 $args{should_coerce} = delete $args{coerce}
208 if exists $args{coerce};
210 if (exists $args{isa}) {
211 my $type_constraint = delete $args{isa};
212 $type_constraint =~ s/\s//g;
213 my @type_constraints = split /\|/, $type_constraint;
216 my $optimized_constraints = Mouse::TypeRegistry->optimized_constraints;
217 if (@type_constraints == 1) {
218 $code = $optimized_constraints->{$type_constraints[0]} ||
219 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type_constraints[0] };
220 $args{type_constraint} = $type_constraints[0];
222 my @code_list = map {
224 $optimized_constraints->{$type} ||
225 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type }
228 for my $code (@code_list) {
229 return 1 if $code->();
233 $args{type_constraint} = \@type_constraints;
235 $args{find_type_constraint} = $code;
238 my $attribute = $self->new(%args);
240 $attribute->_create_args(\%args);
242 $class->add_attribute($attribute);
244 # install an accessor
245 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
246 my $accessor = $attribute->generate_accessor;
247 $class->add_method($name => $accessor);
250 for my $method (qw/predicate clearer/) {
251 my $predicate = "has_$method";
252 if ($attribute->$predicate) {
253 my $generator = "generate_$method";
254 my $coderef = $attribute->$generator;
255 $class->add_method($attribute->$method => $coderef);
259 if ($attribute->has_handles) {
260 my $method_map = $attribute->generate_handles;
261 for my $method_name (keys %$method_map) {
262 $class->add_method($method_name => $method_map->{$method_name});
269 sub canonicalize_args {
274 if ($args{lazy_build}) {
277 $args{builder} = "_build_${name}"
278 if !exists($args{builder});
280 $args{clearer} = "_clear${name}" if !exists($args{clearer});
281 $args{predicate} = "_has${name}" if !exists($args{predicate});
284 $args{clearer} = "clear_${name}" if !exists($args{clearer});
285 $args{predicate} = "has_${name}" if !exists($args{predicate});
297 confess "You can not use lazy_build and default for the same attribute ($name)"
298 if $args->{lazy_build} && exists $args->{default};
300 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
302 && !exists($args->{default})
303 && !exists($args->{builder});
305 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
306 if ref($args->{default})
307 && ref($args->{default}) ne 'CODE';
309 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
310 if $args->{auto_deref} && !exists($args->{isa});
312 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
313 if $args->{auto_deref}
314 && $args->{isa} ne 'ArrayRef'
315 && $args->{isa} ne 'HashRef';
317 if ($args->{trigger}) {
318 if (ref($args->{trigger}) eq 'HASH') {
319 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
322 confess "Trigger must be a CODE ref on attribute ($name)"
323 if ref($args->{trigger}) ne 'CODE';
329 sub verify_type_constraint {
333 my $type = $self->type_constraint_as_string
335 my $constraint = $self->find_type_constraint;
337 return 1 if $constraint->($_);
339 my $name = $self->name;
340 my $display = defined($_) ? overload::StrVal($_) : 'undef';
341 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
344 sub coerce_constraint {
345 my($self, $value) = @_;
346 my $type = $self->type_constraint
348 return Mouse::TypeRegistry->typecast_constraints($self->associated_class->name, $self->find_type_constraint, $type, $value);
351 sub _canonicalize_handles {
355 if (ref($handles) eq 'HASH') {
358 elsif (ref($handles) eq 'ARRAY') {
359 return map { $_ => $_ } @$handles;
362 confess "Unable to canonicalize the 'handles' option with $handles";
370 my %args = ($self->get_parent_args($class, $name), @_);
372 $self->create($class, $name, %args);
375 sub get_parent_args {
380 for my $super ($class->linearized_isa) {
381 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
383 return %{ $super_attr->_create_args };
386 confess "Could not find an attribute by the name of '$name' to inherit from";
395 Mouse::Meta::Attribute - attribute metaclass
399 =head2 new %args -> Mouse::Meta::Attribute
401 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
403 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
405 Creates a new attribute in OwnerClass. Accessors and helper methods are
406 installed. Some error checking is done.
408 =head2 name -> AttributeName
410 =head2 associated_class -> OwnerClass
412 =head2 is_required -> Bool
414 =head2 default -> Item
416 =head2 has_default -> Bool
418 =head2 is_lazy -> Bool
420 =head2 predicate -> MethodName | Undef
422 =head2 has_predicate -> Bool
424 =head2 clearer -> MethodName | Undef
426 =head2 has_clearer -> Bool
428 =head2 handles -> { LocalName => RemoteName }
430 =head2 has_handles -> Bool
432 =head2 is_weak_ref -> Bool
434 =head2 init_arg -> Str
436 =head2 type_constraint -> Str
438 =head2 has_type_constraint -> Bool
440 =head2 trigger => CODE | Undef
442 =head2 has_trigger -> Bool
444 =head2 builder => MethodName | Undef
446 =head2 has_builder -> Bool
448 =head2 is_lazy_build => Bool
450 =head2 should_auto_deref -> Bool
452 Informational methods.
454 =head2 generate_accessor -> CODE
456 Creates a new code reference for the attribute's accessor.
458 =head2 generate_predicate -> CODE
460 Creates a new code reference for the attribute's predicate.
462 =head2 generate_clearer -> CODE
464 Creates a new code reference for the attribute's clearer.
466 =head2 generate_handles -> { MethodName => CODE }
468 Creates a new code reference for each of the attribute's handles methods.
470 =head2 find_type_constraint -> CODE
472 Returns a code reference which can be used to check that a given value passes
473 this attribute's type constraint;
475 =head2 verify_type_constraint Item -> 1 | ERROR
477 Checks that the given value passes this attribute's type constraint. Returns 1
478 on success, otherwise C<confess>es.
480 =head2 canonicalize_args Name, %args -> %args
482 Canonicalizes some arguments to create. In particular, C<lazy_build> is
483 canonicalized into C<lazy>, C<builder>, etc.
485 =head2 validate_args Name, \%args -> 1 | ERROR
487 Checks that the arguments to create the attribute (ie those specified by
490 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
492 Creates a new attribute in OwnerClass, inheriting options from parent classes.
493 Accessors and helper methods are installed. Some error checking is done.
495 =head2 get_parent_args OwnerClass, AttributeName -> Hash
497 Returns the options that the parent class of C<OwnerClass> used for attribute