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 trigger { $_[0]->{trigger} }
37 sub builder { $_[0]->{builder} }
38 sub should_auto_deref { $_[0]->{auto_deref} }
39 sub should_coerce { $_[0]->{should_coerce} }
41 sub has_default { exists $_[0]->{default} }
42 sub has_predicate { exists $_[0]->{predicate} }
43 sub has_clearer { exists $_[0]->{clearer} }
44 sub has_handles { exists $_[0]->{handles} }
45 sub has_type_constraint { exists $_[0]->{type_constraint} }
46 sub has_trigger { exists $_[0]->{trigger} }
47 sub has_builder { exists $_[0]->{builder} }
50 $_[0]->{_create_args} = $_[1] if @_ > 1;
56 my $name = $self->name;
57 my $key = "'" . $name . "'";
61 sub generate_accessor {
62 my $attribute = shift;
64 my $name = $attribute->name;
65 my $default = $attribute->default;
66 my $constraint = $attribute->type_constraint;
67 my $builder = $attribute->builder;
68 my $trigger = $attribute->trigger;
69 my $is_weak = $attribute->is_weak_ref;
70 my $should_deref = $attribute->should_auto_deref;
71 my $should_coerce = $attribute->should_coerce;
74 my $key = $attribute->inlined_name;
77 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
79 if ($attribute->_is_metadata eq 'rw') {
81 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
82 'if (@_ >= 2) {' . "\n";
87 $accessor .= 'my $val = ';
91 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
92 'Mouse::Util::TypeConstraints->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{type_constraint}, '.$value.');';
94 $accessor .= $value.';';
98 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
99 'unless ($constraint->check($val)) {
100 $attribute->verify_type_constraint_error($name, $val, $attribute->{type_constraint});
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 $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
116 $accessor .= '$trigger->('.$self.', '.$value.');' . "\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->name 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 confess "Got isa => $args{isa}, but Mouse does not yet support parameterized types for containers other than ArrayRef and HashRef (rt.cpan.org #39795)"
216 if $args{isa} =~ /^([^\[]+)\[.+\]$/ &&
222 my $type_constraint = delete $args{isa};
223 $args{type_constraint}= Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($type_constraint);
226 my $attribute = $self->new($name, %args);
228 $attribute->_create_args(\%args);
230 $class->add_attribute($attribute);
232 # install an accessor
233 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
234 my $accessor = $attribute->generate_accessor;
235 $class->add_method($name => $accessor);
238 for my $method (qw/predicate clearer/) {
239 my $predicate = "has_$method";
240 if ($attribute->$predicate) {
241 my $generator = "generate_$method";
242 my $coderef = $attribute->$generator;
243 $class->add_method($attribute->$method => $coderef);
247 if ($attribute->has_handles) {
248 my $method_map = $attribute->generate_handles;
249 for my $method_name (keys %$method_map) {
250 $class->add_method($method_name => $method_map->{$method_name});
257 sub canonicalize_args {
262 if ($args{lazy_build}) {
265 $args{builder} = "_build_${name}"
266 if !exists($args{builder});
268 $args{clearer} = "_clear${name}" if !exists($args{clearer});
269 $args{predicate} = "_has${name}" if !exists($args{predicate});
272 $args{clearer} = "clear_${name}" if !exists($args{clearer});
273 $args{predicate} = "has_${name}" if !exists($args{predicate});
285 confess "You can not use lazy_build and default for the same attribute ($name)"
286 if $args->{lazy_build} && exists $args->{default};
288 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
290 && !exists($args->{default})
291 && !exists($args->{builder});
293 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
294 if ref($args->{default})
295 && ref($args->{default}) ne 'CODE';
297 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
298 if $args->{auto_deref} && !exists($args->{isa});
300 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
301 if $args->{auto_deref}
302 && $args->{isa} ne 'ArrayRef'
303 && $args->{isa} ne 'HashRef';
305 if ($args->{trigger}) {
306 if (ref($args->{trigger}) eq 'HASH') {
307 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
310 confess "Trigger must be a CODE ref on attribute ($name)"
311 if ref($args->{trigger}) ne 'CODE';
317 sub verify_against_type_constraint {
318 return 1 unless $_[0]->{type_constraint};
321 return 1 if $_[0]->{type_constraint}->check($_);
324 $self->verify_type_constraint_error($self->name, $_, $self->{type_constraint});
327 sub verify_type_constraint_error {
328 my($self, $name, $value, $type) = @_;
329 $type = ref($type) eq 'ARRAY' ? join '|', map { $_->name } @{ $type } : $type->name;
330 my $display = defined($value) ? overload::StrVal($value) : 'undef';
331 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
334 sub coerce_constraint { ## my($self, $value) = @_;
335 my $type = $_[0]->{type_constraint}
337 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->type_constraint, $_[1]);
340 sub _canonicalize_handles {
344 if (ref($handles) eq 'HASH') {
347 elsif (ref($handles) eq 'ARRAY') {
348 return map { $_ => $_ } @$handles;
351 confess "Unable to canonicalize the 'handles' option with $handles";
359 my %args = ($self->get_parent_args($class, $name), @_);
361 $self->create($class, $name, %args);
364 sub get_parent_args {
369 for my $super ($class->linearized_isa) {
370 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
372 return %{ $super_attr->_create_args };
375 confess "Could not find an attribute by the name of '$name' to inherit from";
384 Mouse::Meta::Attribute - attribute metaclass
388 =head2 new %args -> Mouse::Meta::Attribute
390 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
392 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
394 Creates a new attribute in OwnerClass. Accessors and helper methods are
395 installed. Some error checking is done.
397 =head2 name -> AttributeName
399 =head2 associated_class -> OwnerClass
401 =head2 is_required -> Bool
403 =head2 default -> Item
405 =head2 has_default -> Bool
407 =head2 is_lazy -> Bool
409 =head2 predicate -> MethodName | Undef
411 =head2 has_predicate -> Bool
413 =head2 clearer -> MethodName | Undef
415 =head2 has_clearer -> Bool
417 =head2 handles -> { LocalName => RemoteName }
419 =head2 has_handles -> Bool
421 =head2 is_weak_ref -> Bool
423 =head2 init_arg -> Str
425 =head2 type_constraint -> Str
427 =head2 has_type_constraint -> Bool
429 =head2 trigger => CODE | Undef
431 =head2 has_trigger -> Bool
433 =head2 builder => MethodName | Undef
435 =head2 has_builder -> Bool
437 =head2 is_lazy_build => Bool
439 =head2 should_auto_deref -> Bool
441 Informational methods.
443 =head2 generate_accessor -> CODE
445 Creates a new code reference for the attribute's accessor.
447 =head2 generate_predicate -> CODE
449 Creates a new code reference for the attribute's predicate.
451 =head2 generate_clearer -> CODE
453 Creates a new code reference for the attribute's clearer.
455 =head2 generate_handles -> { MethodName => CODE }
457 Creates a new code reference for each of the attribute's handles methods.
459 =head2 verify_against_type_constraint Item -> 1 | ERROR
461 Checks that the given value passes this attribute's type constraint. Returns 1
462 on success, otherwise C<confess>es.
464 =head2 canonicalize_args Name, %args -> %args
466 Canonicalizes some arguments to create. In particular, C<lazy_build> is
467 canonicalized into C<lazy>, C<builder>, etc.
469 =head2 validate_args Name, \%args -> 1 | ERROR
471 Checks that the arguments to create the attribute (ie those specified by
474 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
476 Creates a new attribute in OwnerClass, inheriting options from parent classes.
477 Accessors and helper methods are installed. Some error checking is done.
479 =head2 get_parent_args OwnerClass, AttributeName -> Hash
481 Returns the options that the parent class of C<OwnerClass> used for attribute