1 package Mouse::Meta::Attribute;
13 my $name = $args{name};
15 $args{init_arg} = $name
16 unless exists $args{init_arg};
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 trigger { $_[0]->{trigger} }
37 sub builder { $_[0]->{builder} }
38 sub should_auto_deref { $_[0]->{auto_deref} }
39 sub should_coerce { $_[0]->{should_coerce} }
40 sub find_type_constraint { $_[0]->{find_type_constraint} }
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} }
51 $_[0]->{_create_args} = $_[1] if @_ > 1;
57 my $name = $self->name;
58 my $key = "'" . $name . "'";
62 sub generate_accessor {
63 my $attribute = shift;
65 my $name = $attribute->name;
66 my $default = $attribute->default;
67 my $constraint = $attribute->find_type_constraint;
68 my $builder = $attribute->builder;
69 my $trigger = $attribute->trigger;
70 my $is_weak = $attribute->is_weak_ref;
71 my $should_deref = $attribute->should_auto_deref;
72 my $should_coerce = $attribute->should_coerce;
75 my $key = $attribute->inlined_name;
77 my $accessor = "sub {\n";
78 if ($attribute->_is_metadata eq 'rw') {
79 $accessor .= 'if (scalar(@_) >= 2) {' . "\n";
84 $accessor .= 'my $val = ';
86 $accessor .= 'Mouse::TypeRegistry->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');';
88 $accessor .= $value.';';
90 $accessor .= 'local $_ = $val;';
92 unless ($constraint->()) {
93 $attribute->verify_type_constraint_error($name, $_, $attribute->type_constraint);
98 # if there's nothing left to do for the attribute we can return during
100 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
102 $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
105 $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
109 $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
115 $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
118 if ($attribute->is_lazy) {
119 $accessor .= $self.'->{'.$key.'} = ';
121 $accessor .= $attribute->has_builder
123 : ref($default) eq 'CODE'
124 ? '$default->('.$self.')'
126 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
130 my $type_constraint = $attribute->type_constraint;
131 if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
132 $accessor .= 'if (wantarray) {
133 return @{ '.$self.'->{'.$key.'} || [] };
137 $accessor .= 'if (wantarray) {
138 return %{ '.$self.'->{'.$key.'} || {} };
143 $accessor .= 'return '.$self.'->{'.$key.'};
146 my $sub = eval $accessor;
151 sub generate_predicate {
152 my $attribute = shift;
153 my $key = $attribute->inlined_name;
155 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
157 my $sub = eval $predicate;
162 sub generate_clearer {
163 my $attribute = shift;
164 my $key = $attribute->inlined_name;
166 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
168 my $sub = eval $clearer;
173 sub generate_handles {
174 my $attribute = shift;
175 my $reader = $attribute->name;
176 my %handles = $attribute->_canonicalize_handles($attribute->handles);
180 for my $local_method (keys %handles) {
181 my $remote_method = $handles{$local_method};
185 $self->'.$reader.'->'.$remote_method.'(@_)
188 $method_map{$local_method} = eval $method;
196 my ($self, $class, $name, %args) = @_;
199 $args{associated_class} = $class;
201 %args = $self->canonicalize_args($name, %args);
202 $self->validate_args($name, \%args);
204 $args{should_coerce} = delete $args{coerce}
205 if exists $args{coerce};
207 if (exists $args{isa}) {
208 my $type_constraint = delete $args{isa};
209 $type_constraint =~ s/\s//g;
210 my @type_constraints = split /\|/, $type_constraint;
213 my $optimized_constraints = Mouse::TypeRegistry->optimized_constraints;
214 if (@type_constraints == 1) {
215 $code = $optimized_constraints->{$type_constraints[0]} ||
216 sub { Scalar::Util::blessed($_) && $_->isa($type_constraints[0]) };
217 $args{type_constraint} = $type_constraints[0];
219 my @code_list = map {
221 $optimized_constraints->{$type} ||
222 sub { Scalar::Util::blessed($_) && $_->isa($type) }
225 for my $code (@code_list) {
226 return 1 if $code->();
230 $args{type_constraint} = \@type_constraints;
232 $args{find_type_constraint} = $code;
235 my $attribute = $self->new(%args);
237 $attribute->_create_args(\%args);
239 $class->add_attribute($attribute);
241 # install an accessor
242 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
243 my $accessor = $attribute->generate_accessor;
244 $class->add_method($name => $accessor);
247 for my $method (qw/predicate clearer/) {
248 my $predicate = "has_$method";
249 if ($attribute->$predicate) {
250 my $generator = "generate_$method";
251 my $coderef = $attribute->$generator;
252 $class->add_method($attribute->$method => $coderef);
256 if ($attribute->has_handles) {
257 my $method_map = $attribute->generate_handles;
258 for my $method_name (keys %$method_map) {
259 $class->add_method($method_name => $method_map->{$method_name});
266 sub canonicalize_args {
271 if ($args{lazy_build}) {
274 $args{builder} = "_build_${name}"
275 if !exists($args{builder});
277 $args{clearer} = "_clear${name}" if !exists($args{clearer});
278 $args{predicate} = "_has${name}" if !exists($args{predicate});
281 $args{clearer} = "clear_${name}" if !exists($args{clearer});
282 $args{predicate} = "has_${name}" if !exists($args{predicate});
294 confess "You can not use lazy_build and default for the same attribute ($name)"
295 if $args->{lazy_build} && exists $args->{default};
297 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
299 && !exists($args->{default})
300 && !exists($args->{builder});
302 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
303 if ref($args->{default})
304 && ref($args->{default}) ne 'CODE';
306 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
307 if $args->{auto_deref} && !exists($args->{isa});
309 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
310 if $args->{auto_deref}
311 && $args->{isa} ne 'ArrayRef'
312 && $args->{isa} ne 'HashRef';
314 if ($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_type_constraint {
327 return 1 unless $_[0]->{type_constraint};
330 return 1 if $_[0]->{find_type_constraint}->($_);
333 $self->verify_type_constraint_error($self->name, $_, $self->type_constraint);
336 sub verify_type_constraint_error {
337 my($self, $name, $value, $type) = @_;
338 $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type;
339 my $display = defined($_) ? overload::StrVal($_) : 'undef';
340 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
343 sub coerce_constraint { ## my($self, $value) = @_;
344 my $type = $_[0]->{type_constraint}
346 return Mouse::TypeRegistry->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
349 sub _canonicalize_handles {
353 if (ref($handles) eq 'HASH') {
356 elsif (ref($handles) eq 'ARRAY') {
357 return map { $_ => $_ } @$handles;
360 confess "Unable to canonicalize the 'handles' option with $handles";
368 my %args = ($self->get_parent_args($class, $name), @_);
370 $self->create($class, $name, %args);
373 sub get_parent_args {
378 for my $super ($class->linearized_isa) {
379 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
381 return %{ $super_attr->_create_args };
384 confess "Could not find an attribute by the name of '$name' to inherit from";
393 Mouse::Meta::Attribute - attribute metaclass
397 =head2 new %args -> Mouse::Meta::Attribute
399 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
401 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
403 Creates a new attribute in OwnerClass. Accessors and helper methods are
404 installed. Some error checking is done.
406 =head2 name -> AttributeName
408 =head2 associated_class -> OwnerClass
410 =head2 is_required -> Bool
412 =head2 default -> Item
414 =head2 has_default -> Bool
416 =head2 is_lazy -> Bool
418 =head2 predicate -> MethodName | Undef
420 =head2 has_predicate -> Bool
422 =head2 clearer -> MethodName | Undef
424 =head2 has_clearer -> Bool
426 =head2 handles -> { LocalName => RemoteName }
428 =head2 has_handles -> Bool
430 =head2 is_weak_ref -> Bool
432 =head2 init_arg -> Str
434 =head2 type_constraint -> Str
436 =head2 has_type_constraint -> Bool
438 =head2 trigger => CODE | Undef
440 =head2 has_trigger -> Bool
442 =head2 builder => MethodName | Undef
444 =head2 has_builder -> Bool
446 =head2 is_lazy_build => Bool
448 =head2 should_auto_deref -> Bool
450 Informational methods.
452 =head2 generate_accessor -> CODE
454 Creates a new code reference for the attribute's accessor.
456 =head2 generate_predicate -> CODE
458 Creates a new code reference for the attribute's predicate.
460 =head2 generate_clearer -> CODE
462 Creates a new code reference for the attribute's clearer.
464 =head2 generate_handles -> { MethodName => CODE }
466 Creates a new code reference for each of the attribute's handles methods.
468 =head2 find_type_constraint -> CODE
470 Returns a code reference which can be used to check that a given value passes
471 this attribute's type constraint;
473 =head2 verify_type_constraint Item -> 1 | ERROR
475 Checks that the given value passes this attribute's type constraint. Returns 1
476 on success, otherwise C<confess>es.
478 =head2 canonicalize_args Name, %args -> %args
480 Canonicalizes some arguments to create. In particular, C<lazy_build> is
481 canonicalized into C<lazy>, C<builder>, etc.
483 =head2 validate_args Name, \%args -> 1 | ERROR
485 Checks that the arguments to create the attribute (ie those specified by
488 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
490 Creates a new attribute in OwnerClass, inheriting options from parent classes.
491 Accessors and helper methods are installed. Some error checking is done.
493 =head2 get_parent_args OwnerClass, AttributeName -> Hash
495 Returns the options that the parent class of C<OwnerClass> used for attribute