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;
76 my $accessor = "sub {\n";
77 if ($attribute->_is_metadata eq 'rw') {
78 $accessor .= 'if (@_ >= 2) {' . "\n";
83 $accessor .= 'my $val = ';
85 $accessor .= 'Mouse::Util::TypeConstraints->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');';
87 $accessor .= $value.';';
89 $accessor .= 'local $_ = $val;';
91 unless ($constraint->()) {
92 $attribute->verify_type_constraint_error($name, $_, $attribute->type_constraint);
97 # if there's nothing left to do for the attribute we can return during
99 $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
101 $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
104 $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
108 $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
114 $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
117 if ($attribute->is_lazy) {
118 $accessor .= $self.'->{'.$key.'} = ';
120 $accessor .= $attribute->has_builder
122 : ref($default) eq 'CODE'
123 ? '$default->('.$self.')'
125 $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
129 my $type_constraint = $attribute->type_constraint;
130 if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
131 $accessor .= 'if (wantarray) {
132 return @{ '.$self.'->{'.$key.'} || [] };
136 $accessor .= 'if (wantarray) {
137 return %{ '.$self.'->{'.$key.'} || {} };
142 $accessor .= 'return '.$self.'->{'.$key.'};
145 my $sub = eval $accessor;
150 sub generate_predicate {
151 my $attribute = shift;
152 my $key = $attribute->inlined_name;
154 my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
156 my $sub = eval $predicate;
161 sub generate_clearer {
162 my $attribute = shift;
163 my $key = $attribute->inlined_name;
165 my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
167 my $sub = eval $clearer;
172 sub generate_handles {
173 my $attribute = shift;
174 my $reader = $attribute->name;
175 my %handles = $attribute->_canonicalize_handles($attribute->handles);
179 for my $local_method (keys %handles) {
180 my $remote_method = $handles{$local_method};
184 $self->'.$reader.'->'.$remote_method.'(@_)
187 $method_map{$local_method} = eval $method;
194 my $optimized_constraints;
195 sub _build_type_constraint {
197 $optimized_constraints ||= Mouse::Util::TypeConstraints->optimized_constraints;
199 if ($spec =~ /^([^\[]+)\[(.+)\]$/) {
203 my $parent = _build_type_constraint($constraint);
204 my $child = _build_type_constraint($param);
205 if ($constraint eq 'ArrayRef') {
208 " if (\$parent->(\$_)) {\n" .
209 " foreach my \$e (@\$_) {\n" .
210 " local \$_ = \$e;\n" .
211 " return () unless \$child->(\$_);\n" .
218 $code = eval $code_str or Carp::confess($@);
219 } elsif ($constraint eq 'HashRef') {
222 " if (\$parent->(\$_)) {\n" .
223 " foreach my \$e (values %\$_) {\n" .
224 " local \$_ = \$e;\n" .
225 " return () unless \$child->(\$_);\n" .
232 $code = eval $code_str or Carp::confess($@);
234 Carp::confess("Support for parameterized types other than ArrayRef or HashRef is not implemented yet");
236 $optimized_constraints->{$spec} = $code;
238 $code = $optimized_constraints->{ $spec };
240 $code = sub { Scalar::Util::blessed($_) && $_->isa($spec) };
241 $optimized_constraints->{$spec} = $code;
248 my ($self, $class, $name, %args) = @_;
251 $args{associated_class} = $class;
253 %args = $self->canonicalize_args($name, %args);
254 $self->validate_args($name, \%args);
256 $args{should_coerce} = delete $args{coerce}
257 if exists $args{coerce};
259 if (exists $args{isa}) {
260 warn "Got isa => $args{isa}, but Mouse does not yet support parameterized types for containers other than ArrayRef and HashRef (rt.cpan.org #39795)"
261 if $args{isa} =~ /^([^\[]+)\[.+\]$/ &&
265 my $type_constraint = delete $args{isa};
266 $type_constraint =~ s/\s//g;
267 my @type_constraints = split /\|/, $type_constraint;
270 if (@type_constraints == 1) {
271 $code = _build_type_constraint($type_constraints[0]);
272 $args{type_constraint} = $type_constraints[0];
274 my @code_list = map {
275 _build_type_constraint($_)
278 for my $code (@code_list) {
279 return 1 if $code->();
283 $args{type_constraint} = \@type_constraints;
285 $args{find_type_constraint} = $code;
288 my $attribute = $self->new($name, %args);
290 $attribute->_create_args(\%args);
292 $class->add_attribute($attribute);
294 # install an accessor
295 if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
296 my $accessor = $attribute->generate_accessor;
297 $class->add_method($name => $accessor);
300 for my $method (qw/predicate clearer/) {
301 my $predicate = "has_$method";
302 if ($attribute->$predicate) {
303 my $generator = "generate_$method";
304 my $coderef = $attribute->$generator;
305 $class->add_method($attribute->$method => $coderef);
309 if ($attribute->has_handles) {
310 my $method_map = $attribute->generate_handles;
311 for my $method_name (keys %$method_map) {
312 $class->add_method($method_name => $method_map->{$method_name});
319 sub canonicalize_args {
324 if ($args{lazy_build}) {
327 $args{builder} = "_build_${name}"
328 if !exists($args{builder});
330 $args{clearer} = "_clear${name}" if !exists($args{clearer});
331 $args{predicate} = "_has${name}" if !exists($args{predicate});
334 $args{clearer} = "clear_${name}" if !exists($args{clearer});
335 $args{predicate} = "has_${name}" if !exists($args{predicate});
347 confess "You can not use lazy_build and default for the same attribute ($name)"
348 if $args->{lazy_build} && exists $args->{default};
350 confess "You cannot have lazy attribute ($name) without specifying a default value for it"
352 && !exists($args->{default})
353 && !exists($args->{builder});
355 confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
356 if ref($args->{default})
357 && ref($args->{default}) ne 'CODE';
359 confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
360 if $args->{auto_deref} && !exists($args->{isa});
362 confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
363 if $args->{auto_deref}
364 && $args->{isa} ne 'ArrayRef'
365 && $args->{isa} ne 'HashRef';
367 if ($args->{trigger}) {
368 if (ref($args->{trigger}) eq 'HASH') {
369 Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
372 confess "Trigger must be a CODE ref on attribute ($name)"
373 if ref($args->{trigger}) ne 'CODE';
379 sub verify_against_type_constraint {
380 return 1 unless $_[0]->{type_constraint};
383 return 1 if $_[0]->{find_type_constraint}->($_);
386 $self->verify_type_constraint_error($self->name, $_, $self->type_constraint);
389 sub verify_type_constraint_error {
390 my($self, $name, $value, $type) = @_;
391 $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type;
392 my $display = defined($_) ? overload::StrVal($_) : 'undef';
393 Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
396 sub coerce_constraint { ## my($self, $value) = @_;
397 my $type = $_[0]->{type_constraint}
399 return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
402 sub _canonicalize_handles {
406 if (ref($handles) eq 'HASH') {
409 elsif (ref($handles) eq 'ARRAY') {
410 return map { $_ => $_ } @$handles;
413 confess "Unable to canonicalize the 'handles' option with $handles";
421 my %args = ($self->get_parent_args($class, $name), @_);
423 $self->create($class, $name, %args);
426 sub get_parent_args {
431 for my $super ($class->linearized_isa) {
432 my $super_attr = $super->can("meta") && $super->meta->get_attribute($name)
434 return %{ $super_attr->_create_args };
437 confess "Could not find an attribute by the name of '$name' to inherit from";
446 Mouse::Meta::Attribute - attribute metaclass
450 =head2 new %args -> Mouse::Meta::Attribute
452 Instantiates a new Mouse::Meta::Attribute. Does nothing else.
454 =head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
456 Creates a new attribute in OwnerClass. Accessors and helper methods are
457 installed. Some error checking is done.
459 =head2 name -> AttributeName
461 =head2 associated_class -> OwnerClass
463 =head2 is_required -> Bool
465 =head2 default -> Item
467 =head2 has_default -> Bool
469 =head2 is_lazy -> Bool
471 =head2 predicate -> MethodName | Undef
473 =head2 has_predicate -> Bool
475 =head2 clearer -> MethodName | Undef
477 =head2 has_clearer -> Bool
479 =head2 handles -> { LocalName => RemoteName }
481 =head2 has_handles -> Bool
483 =head2 is_weak_ref -> Bool
485 =head2 init_arg -> Str
487 =head2 type_constraint -> Str
489 =head2 has_type_constraint -> Bool
491 =head2 trigger => CODE | Undef
493 =head2 has_trigger -> Bool
495 =head2 builder => MethodName | Undef
497 =head2 has_builder -> Bool
499 =head2 is_lazy_build => Bool
501 =head2 should_auto_deref -> Bool
503 Informational methods.
505 =head2 generate_accessor -> CODE
507 Creates a new code reference for the attribute's accessor.
509 =head2 generate_predicate -> CODE
511 Creates a new code reference for the attribute's predicate.
513 =head2 generate_clearer -> CODE
515 Creates a new code reference for the attribute's clearer.
517 =head2 generate_handles -> { MethodName => CODE }
519 Creates a new code reference for each of the attribute's handles methods.
521 =head2 find_type_constraint -> CODE
523 Returns a code reference which can be used to check that a given value passes
524 this attribute's type constraint;
526 =head2 verify_against_type_constraint Item -> 1 | ERROR
528 Checks that the given value passes this attribute's type constraint. Returns 1
529 on success, otherwise C<confess>es.
531 =head2 canonicalize_args Name, %args -> %args
533 Canonicalizes some arguments to create. In particular, C<lazy_build> is
534 canonicalized into C<lazy>, C<builder>, etc.
536 =head2 validate_args Name, \%args -> 1 | ERROR
538 Checks that the arguments to create the attribute (ie those specified by
541 =head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
543 Creates a new attribute in OwnerClass, inheriting options from parent classes.
544 Accessors and helper methods are installed. Some error checking is done.
546 =head2 get_parent_args OwnerClass, AttributeName -> Hash
548 Returns the options that the parent class of C<OwnerClass> used for attribute