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} }
53 $_[0]->{_create_args} = $_[1] if @_ > 1;
59 my $name = $self->name;
60 my $key = "'" . $name . "'";
64 sub generate_accessor {
65 my $attribute = shift;
67 my $name = $attribute->name;
68 my $default = $attribute->default;
69 my $constraint = $attribute->find_type_constraint;
70 my $builder = $attribute->builder;
71 my $trigger = $attribute->trigger;
72 my $is_weak = $attribute->is_weak_ref;
73 my $should_deref = $attribute->should_auto_deref;
74 my $should_coerce = $attribute->should_coerce;
77 my $key = $attribute->inlined_name;
79 my $accessor = "sub {\n";
80 if ($attribute->_is_metadata eq 'rw') {
81 $accessor .= 'if (scalar(@_) >= 2) {' . "\n";
86 $accessor .= 'my $val = ';
88 $accessor .= 'Mouse::TypeRegistry->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');';
90 $accessor .= $value.';';
92 $accessor .= 'local $_ = $val;';
94 unless ($constraint->()) {
95 $attribute->verify_type_constraint_error($name, $_, $attribute->type_constraint);
100 # if there's nothing left to do for the attribute we can return during
102 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
104 $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
107 $accessor .= 'Mouse::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
111 $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
117 $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
120 if ($attribute->is_lazy) {
121 $accessor .= $self.'->{'.$key.'} = ';
123 $accessor .= $attribute->has_builder
125 : ref($default) eq 'CODE'
126 ? '$default->('.$self.')'
128 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
132 my $type_constraint = $attribute->type_constraint;
133 if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
134 $accessor .= 'if (wantarray) {
135 return @{ '.$self.'->{'.$key.'} || [] };
139 $accessor .= 'if (wantarray) {
140 return %{ '.$self.'->{'.$key.'} || {} };
145 $accessor .= 'return '.$self.'->{'.$key.'};
148 my $sub = eval $accessor;
153 sub generate_predicate {
154 my $attribute = shift;
155 my $key = $attribute->inlined_name;
157 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
159 my $sub = eval $predicate;
164 sub generate_clearer {
165 my $attribute = shift;
166 my $key = $attribute->inlined_name;
168 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
170 my $sub = eval $clearer;
175 sub generate_handles {
176 my $attribute = shift;
177 my $reader = $attribute->name;
178 my %handles = $attribute->_canonicalize_handles($attribute->handles);
182 for my $local_method (keys %handles) {
183 my $remote_method = $handles{$local_method};
187 $self->'.$reader.'->'.$remote_method.'(@_)
190 $method_map{$local_method} = eval $method;
198 my ($self, $class, $name, %args) = @_;
201 $args{associated_class} = $class;
203 %args = $self->canonicalize_args($name, %args);
204 $self->validate_args($name, \%args);
206 $args{should_coerce} = delete $args{coerce}
207 if exists $args{coerce};
209 if (exists $args{isa}) {
210 my $type_constraint = delete $args{isa};
211 $type_constraint =~ s/\s//g;
212 my @type_constraints = split /\|/, $type_constraint;
215 my $optimized_constraints = Mouse::TypeRegistry->optimized_constraints;
216 if (@type_constraints == 1) {
217 $code = $optimized_constraints->{$type_constraints[0]} ||
218 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type_constraints[0] };
219 $args{type_constraint} = $type_constraints[0];
221 my @code_list = map {
223 $optimized_constraints->{$type} ||
224 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type }
227 for my $code (@code_list) {
228 return 1 if $code->();
232 $args{type_constraint} = \@type_constraints;
234 $args{find_type_constraint} = $code;
237 my $attribute = $self->new(%args);
239 $attribute->_create_args(\%args);
241 $class->add_attribute($attribute);
243 # install an accessor
244 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
245 my $accessor = $attribute->generate_accessor;
246 $class->add_method($name => $accessor);
249 for my $method (qw/predicate clearer/) {
250 my $predicate = "has_$method";
251 if ($attribute->$predicate) {
252 my $generator = "generate_$method";
253 my $coderef = $attribute->$generator;
254 $class->add_method($attribute->$method => $coderef);
258 if ($attribute->has_handles) {
259 my $method_map = $attribute->generate_handles;
260 for my $method_name (keys %$method_map) {
261 $class->add_method($method_name => $method_map->{$method_name});
268 sub canonicalize_args {
273 if ($args{lazy_build}) {
276 $args{builder} = "_build_${name}"
277 if !exists($args{builder});
279 $args{clearer} = "_clear${name}" if !exists($args{clearer});
280 $args{predicate} = "_has${name}" if !exists($args{predicate});
283 $args{clearer} = "clear_${name}" if !exists($args{clearer});
284 $args{predicate} = "has_${name}" if !exists($args{predicate});
296 confess "You can not use lazy_build and default for the same attribute ($name)"
297 if $args->{lazy_build} && exists $args->{default};
299 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
301 && !exists($args->{default})
302 && !exists($args->{builder});
304 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
305 if ref($args->{default})
306 && ref($args->{default}) ne 'CODE';
308 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
309 if $args->{auto_deref} && !exists($args->{isa});
311 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
312 if $args->{auto_deref}
313 && $args->{isa} ne 'ArrayRef'
314 && $args->{isa} ne 'HashRef';
316 if ($args->{trigger}) {
317 if (ref($args->{trigger}) eq 'HASH') {
318 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
321 confess "Trigger must be a CODE ref on attribute ($name)"
322 if ref($args->{trigger}) ne 'CODE';
328 sub verify_type_constraint {
329 return 1 unless $_[0]->{type_constraint};
332 return 1 if $_[0]->{find_type_constraint}->($_);
335 $self->verify_type_constraint_error($self->name, $_, $self->type_constraint);
338 sub verify_type_constraint_error {
339 my($self, $name, $value, $type) = @_;
340 $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type;
341 my $display = defined($_) ? overload::StrVal($_) : 'undef';
342 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
345 sub coerce_constraint { ## my($self, $value) = @_;
346 my $type = $_[0]->{type_constraint}
348 return Mouse::TypeRegistry->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
351 sub _canonicalize_handles {
355 if (ref($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