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 .= 'my $val = ';
92 $accessor .= '$attribute->coerce_constraint('.$value.');';
94 $accessor .= $value.';';
96 $accessor .= 'local $_ = $val;';
98 unless ($constraint->()) {
99 my $display = defined($_) ? overload::StrVal($_) : "undef";
100 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
105 # if there's nothing left to do for the attribute we can return during
107 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
109 $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
112 $accessor .= 'Mouse::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
116 $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
122 $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
125 if ($attribute->is_lazy) {
126 $accessor .= $self.'->{'.$key.'} = ';
128 $accessor .= $attribute->has_builder
130 : ref($default) eq 'CODE'
131 ? '$default->('.$self.')'
133 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
137 my $type_constraint = $attribute->type_constraint;
138 if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
139 $accessor .= 'if (wantarray) {
140 return @{ '.$self.'->{'.$key.'} || [] };
144 $accessor .= 'if (wantarray) {
145 return %{ '.$self.'->{'.$key.'} || {} };
150 $accessor .= 'return '.$self.'->{'.$key.'};
153 my $sub = eval $accessor;
158 sub generate_predicate {
159 my $attribute = shift;
160 my $key = $attribute->inlined_name;
162 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
164 my $sub = eval $predicate;
169 sub generate_clearer {
170 my $attribute = shift;
171 my $key = $attribute->inlined_name;
173 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
175 my $sub = eval $clearer;
180 sub generate_handles {
181 my $attribute = shift;
182 my $reader = $attribute->name;
183 my %handles = $attribute->_canonicalize_handles($attribute->handles);
187 for my $local_method (keys %handles) {
188 my $remote_method = $handles{$local_method};
192 $self->$reader->$remote_method(@_)
195 $method_map{$local_method} = eval $method;
203 my ($self, $class, $name, %args) = @_;
206 $args{associated_class} = $class;
208 %args = $self->canonicalize_args($name, %args);
209 $self->validate_args($name, \%args);
211 $args{should_coerce} = delete $args{coerce}
212 if exists $args{coerce};
214 if (exists $args{isa}) {
215 my $type_constraint = delete $args{isa};
216 $type_constraint =~ s/\s//g;
217 my @type_constraints = split /\|/, $type_constraint;
220 my $optimized_constraints = Mouse::TypeRegistry->optimized_constraints;
221 if (@type_constraints == 1) {
222 $code = $optimized_constraints->{$type_constraints[0]} ||
223 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type_constraints[0] };
224 $args{type_constraint} = $type_constraints[0];
226 my @code_list = map {
228 $optimized_constraints->{$type} ||
229 sub { Mouse::Util::blessed($_) && Mouse::Util::blessed($_) eq $type }
232 for my $code (@code_list) {
233 return 1 if $code->();
237 $args{type_constraint} = \@type_constraints;
239 $args{find_type_constraint} = $code;
242 my $attribute = $self->new(%args);
244 $attribute->_create_args(\%args);
246 $class->add_attribute($attribute);
248 # install an accessor
249 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
250 my $accessor = $attribute->generate_accessor;
251 $class->add_method($name => $accessor);
254 for my $method (qw/predicate clearer/) {
255 my $predicate = "has_$method";
256 if ($attribute->$predicate) {
257 my $generator = "generate_$method";
258 my $coderef = $attribute->$generator;
259 $class->add_method($attribute->$method => $coderef);
263 if ($attribute->has_handles) {
264 my $method_map = $attribute->generate_handles;
265 for my $method_name (keys %$method_map) {
266 $class->add_method($method_name => $method_map->{$method_name});
273 sub canonicalize_args {
278 if ($args{lazy_build}) {
281 $args{builder} = "_build_${name}"
282 if !exists($args{builder});
284 $args{clearer} = "_clear${name}" if !exists($args{clearer});
285 $args{predicate} = "_has${name}" if !exists($args{predicate});
288 $args{clearer} = "clear_${name}" if !exists($args{clearer});
289 $args{predicate} = "has_${name}" if !exists($args{predicate});
301 confess "You can not use lazy_build and default for the same attribute ($name)"
302 if $args->{lazy_build} && exists $args->{default};
304 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
306 && !exists($args->{default})
307 && !exists($args->{builder});
309 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
310 if ref($args->{default})
311 && ref($args->{default}) ne 'CODE';
313 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
314 if $args->{auto_deref} && !exists($args->{isa});
316 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
317 if $args->{auto_deref}
318 && $args->{isa} ne 'ArrayRef'
319 && $args->{isa} ne 'HashRef';
321 if ($args->{trigger}) {
322 if (ref($args->{trigger}) eq 'HASH') {
323 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
326 confess "Trigger must be a CODE ref on attribute ($name)"
327 if ref($args->{trigger}) ne 'CODE';
333 sub verify_type_constraint {
334 return 1 unless $_[0]->{type_constraint};
337 return 1 if $_[0]->{find_type_constraint}->($_);
340 my $type = $self->type_constraint_as_string;
342 my $name = $self->name;
343 my $display = defined($_) ? overload::StrVal($_) : 'undef';
344 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
347 sub coerce_constraint { ## my($self, $value) = @_;
348 my $type = $_[0]->{type_constraint}
350 return Mouse::TypeRegistry->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
353 sub _canonicalize_handles {
357 if (ref($handles) eq 'HASH') {
360 elsif (ref($handles) eq 'ARRAY') {
361 return map { $_ => $_ } @$handles;
364 confess "Unable to canonicalize the 'handles' option with $handles";
372 my %args = ($self->get_parent_args($class, $name), @_);
374 $self->create($class, $name, %args);
377 sub get_parent_args {
382 for my $super ($class->linearized_isa) {
383 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
385 return %{ $super_attr->_create_args };
388 confess "Could not find an attribute by the name of '$name' to inherit from";
397 Mouse::Meta::Attribute - attribute metaclass
401 =head2 new %args -> Mouse::Meta::Attribute
403 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
405 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
407 Creates a new attribute in OwnerClass. Accessors and helper methods are
408 installed. Some error checking is done.
410 =head2 name -> AttributeName
412 =head2 associated_class -> OwnerClass
414 =head2 is_required -> Bool
416 =head2 default -> Item
418 =head2 has_default -> Bool
420 =head2 is_lazy -> Bool
422 =head2 predicate -> MethodName | Undef
424 =head2 has_predicate -> Bool
426 =head2 clearer -> MethodName | Undef
428 =head2 has_clearer -> Bool
430 =head2 handles -> { LocalName => RemoteName }
432 =head2 has_handles -> Bool
434 =head2 is_weak_ref -> Bool
436 =head2 init_arg -> Str
438 =head2 type_constraint -> Str
440 =head2 has_type_constraint -> Bool
442 =head2 trigger => CODE | Undef
444 =head2 has_trigger -> Bool
446 =head2 builder => MethodName | Undef
448 =head2 has_builder -> Bool
450 =head2 is_lazy_build => Bool
452 =head2 should_auto_deref -> Bool
454 Informational methods.
456 =head2 generate_accessor -> CODE
458 Creates a new code reference for the attribute's accessor.
460 =head2 generate_predicate -> CODE
462 Creates a new code reference for the attribute's predicate.
464 =head2 generate_clearer -> CODE
466 Creates a new code reference for the attribute's clearer.
468 =head2 generate_handles -> { MethodName => CODE }
470 Creates a new code reference for each of the attribute's handles methods.
472 =head2 find_type_constraint -> CODE
474 Returns a code reference which can be used to check that a given value passes
475 this attribute's type constraint;
477 =head2 verify_type_constraint Item -> 1 | ERROR
479 Checks that the given value passes this attribute's type constraint. Returns 1
480 on success, otherwise C<confess>es.
482 =head2 canonicalize_args Name, %args -> %args
484 Canonicalizes some arguments to create. In particular, C<lazy_build> is
485 canonicalized into C<lazy>, C<builder>, etc.
487 =head2 validate_args Name, \%args -> 1 | ERROR
489 Checks that the arguments to create the attribute (ie those specified by
492 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
494 Creates a new attribute in OwnerClass, inheriting options from parent classes.
495 Accessors and helper methods are installed. Some error checking is done.
497 =head2 get_parent_args OwnerClass, AttributeName -> Hash
499 Returns the options that the parent class of C<OwnerClass> used for attribute