1 package Mouse::Meta::Attribute;
10 my ($class, $name, %options) = @_;
12 $options{name} = $name;
14 $options{init_arg} = $name
15 unless exists $options{init_arg};
19 bless \%options, $class;
22 sub name { $_[0]->{name} }
23 sub associated_class { $_[0]->{associated_class} }
24 sub _is_metadata { $_[0]->{is} }
25 sub is_required { $_[0]->{required} }
26 sub default { $_[0]->{default} }
27 sub is_lazy { $_[0]->{lazy} }
28 sub is_lazy_build { $_[0]->{lazy_build} }
29 sub predicate { $_[0]->{predicate} }
30 sub clearer { $_[0]->{clearer} }
31 sub handles { $_[0]->{handles} }
32 sub is_weak_ref { $_[0]->{weak_ref} }
33 sub init_arg { $_[0]->{init_arg} }
34 sub type_constraint { $_[0]->{type_constraint} }
35 sub trigger { $_[0]->{trigger} }
36 sub builder { $_[0]->{builder} }
37 sub should_auto_deref { $_[0]->{auto_deref} }
38 sub should_coerce { $_[0]->{should_coerce} }
39 sub find_type_constraint { $_[0]->{find_type_constraint} }
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->find_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->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');';
94 $accessor .= $value.';';
98 '#line ' . __LINE__ . ' "' . __FILE__ . "\"\n" .
99 'unless ($constraint->($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 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 $type_constraint =~ s/\s+//g;
224 my $code = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($type_constraint);
225 $args{type_constraint} = $type_constraint =~ /\|/ ?
226 [ split (/\|/, $type_constraint ) ] :
229 $args{find_type_constraint} = $code;
232 my $attribute = $self->new($name, %args);
234 $attribute->_create_args(\%args);
236 $class->add_attribute($attribute);
238 # install an accessor
239 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
240 my $accessor = $attribute->generate_accessor;
241 $class->add_method($name => $accessor);
244 for my $method (qw/predicate clearer/) {
245 my $predicate = "has_$method";
246 if ($attribute->$predicate) {
247 my $generator = "generate_$method";
248 my $coderef = $attribute->$generator;
249 $class->add_method($attribute->$method => $coderef);
253 if ($attribute->has_handles) {
254 my $method_map = $attribute->generate_handles;
255 for my $method_name (keys %$method_map) {
256 $class->add_method($method_name => $method_map->{$method_name});
263 sub canonicalize_args {
268 if ($args{lazy_build}) {
271 $args{builder} = "_build_${name}"
272 if !exists($args{builder});
274 $args{clearer} = "_clear${name}" if !exists($args{clearer});
275 $args{predicate} = "_has${name}" if !exists($args{predicate});
278 $args{clearer} = "clear_${name}" if !exists($args{clearer});
279 $args{predicate} = "has_${name}" if !exists($args{predicate});
291 confess "You can not use lazy_build and default for the same attribute ($name)"
292 if $args->{lazy_build} && exists $args->{default};
294 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
296 && !exists($args->{default})
297 && !exists($args->{builder});
299 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
300 if ref($args->{default})
301 && ref($args->{default}) ne 'CODE';
303 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
304 if $args->{auto_deref} && !exists($args->{isa});
306 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
307 if $args->{auto_deref}
308 && $args->{isa} ne 'ArrayRef'
309 && $args->{isa} ne 'HashRef';
311 if ($args->{trigger}) {
312 if (ref($args->{trigger}) eq 'HASH') {
313 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
316 confess "Trigger must be a CODE ref on attribute ($name)"
317 if ref($args->{trigger}) ne 'CODE';
323 sub verify_against_type_constraint {
324 return 1 unless $_[0]->{type_constraint};
327 return 1 if $_[0]->{find_type_constraint}->($_);
330 $self->verify_type_constraint_error($self->name, $_, $self->type_constraint);
333 sub verify_type_constraint_error {
334 my($self, $name, $value, $type) = @_;
335 $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type;
336 my $display = defined($value) ? overload::StrVal($value) : 'undef';
337 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
340 sub coerce_constraint { ## my($self, $value) = @_;
341 my $type = $_[0]->{type_constraint}
343 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
346 sub _canonicalize_handles {
350 if (ref($handles) eq 'HASH') {
353 elsif (ref($handles) eq 'ARRAY') {
354 return map { $_ => $_ } @$handles;
357 confess "Unable to canonicalize the 'handles' option with $handles";
365 my %args = ($self->get_parent_args($class, $name), @_);
367 $self->create($class, $name, %args);
370 sub get_parent_args {
375 for my $super ($class->linearized_isa) {
376 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
378 return %{ $super_attr->_create_args };
381 confess "Could not find an attribute by the name of '$name' to inherit from";
390 Mouse::Meta::Attribute - attribute metaclass
394 =head2 new %args -> Mouse::Meta::Attribute
396 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
398 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
400 Creates a new attribute in OwnerClass. Accessors and helper methods are
401 installed. Some error checking is done.
403 =head2 name -> AttributeName
405 =head2 associated_class -> OwnerClass
407 =head2 is_required -> Bool
409 =head2 default -> Item
411 =head2 has_default -> Bool
413 =head2 is_lazy -> Bool
415 =head2 predicate -> MethodName | Undef
417 =head2 has_predicate -> Bool
419 =head2 clearer -> MethodName | Undef
421 =head2 has_clearer -> Bool
423 =head2 handles -> { LocalName => RemoteName }
425 =head2 has_handles -> Bool
427 =head2 is_weak_ref -> Bool
429 =head2 init_arg -> Str
431 =head2 type_constraint -> Str
433 =head2 has_type_constraint -> Bool
435 =head2 trigger => CODE | Undef
437 =head2 has_trigger -> Bool
439 =head2 builder => MethodName | Undef
441 =head2 has_builder -> Bool
443 =head2 is_lazy_build => Bool
445 =head2 should_auto_deref -> Bool
447 Informational methods.
449 =head2 generate_accessor -> CODE
451 Creates a new code reference for the attribute's accessor.
453 =head2 generate_predicate -> CODE
455 Creates a new code reference for the attribute's predicate.
457 =head2 generate_clearer -> CODE
459 Creates a new code reference for the attribute's clearer.
461 =head2 generate_handles -> { MethodName => CODE }
463 Creates a new code reference for each of the attribute's handles methods.
465 =head2 find_type_constraint -> CODE
467 Returns a code reference which can be used to check that a given value passes
468 this attribute's type constraint;
470 =head2 verify_against_type_constraint Item -> 1 | ERROR
472 Checks that the given value passes this attribute's type constraint. Returns 1
473 on success, otherwise C<confess>es.
475 =head2 canonicalize_args Name, %args -> %args
477 Canonicalizes some arguments to create. In particular, C<lazy_build> is
478 canonicalized into C<lazy>, C<builder>, etc.
480 =head2 validate_args Name, \%args -> 1 | ERROR
482 Checks that the arguments to create the attribute (ie those specified by
485 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
487 Creates a new attribute in OwnerClass, inheriting options from parent classes.
488 Accessors and helper methods are installed. Some error checking is done.
490 =head2 get_parent_args OwnerClass, AttributeName -> Hash
492 Returns the options that the parent class of C<OwnerClass> used for attribute