package Mouse::Meta::Attribute;
use strict;
use warnings;
-require overload;
-use Carp 'confess';
-use Scalar::Util ();
+use Carp ();
-sub new {
- my ($class, $name, %options) = @_;
+use Mouse::Util qw(:meta);
- $options{name} = $name;
+use Mouse::Meta::TypeConstraint;
+use Mouse::Meta::Method::Accessor;
- $options{init_arg} = $name
- unless exists $options{init_arg};
+sub _process_options{
+ my($class, $name, $args) = @_;
- $options{is} ||= '';
- bless \%options, $class;
-}
+ # XXX: for backward compatibility (with method modifiers)
+ if($class->can('canonicalize_args') != \&canonicalize_args){
+ %{$args} = $class->canonicalize_args($name, %{$args});
+ }
-sub name { $_[0]->{name} }
-sub associated_class { $_[0]->{associated_class} }
-sub _is_metadata { $_[0]->{is} }
-sub is_required { $_[0]->{required} }
-sub default { $_[0]->{default} }
-sub is_lazy { $_[0]->{lazy} }
-sub is_lazy_build { $_[0]->{lazy_build} }
-sub predicate { $_[0]->{predicate} }
-sub clearer { $_[0]->{clearer} }
-sub handles { $_[0]->{handles} }
-sub is_weak_ref { $_[0]->{weak_ref} }
-sub init_arg { $_[0]->{init_arg} }
-sub type_constraint { $_[0]->{type_constraint} }
-sub trigger { $_[0]->{trigger} }
-sub builder { $_[0]->{builder} }
-sub should_auto_deref { $_[0]->{auto_deref} }
-sub should_coerce { $_[0]->{should_coerce} }
-sub find_type_constraint { $_[0]->{find_type_constraint} }
+ # taken from Class::MOP::Attribute::new
-sub has_default { exists $_[0]->{default} }
-sub has_predicate { exists $_[0]->{predicate} }
-sub has_clearer { exists $_[0]->{clearer} }
-sub has_handles { exists $_[0]->{handles} }
-sub has_type_constraint { exists $_[0]->{type_constraint} }
-sub has_trigger { exists $_[0]->{trigger} }
-sub has_builder { exists $_[0]->{builder} }
+ defined($name)
+ or $class->throw_error('You must provide a name for the attribute');
-sub _create_args {
- $_[0]->{_create_args} = $_[1] if @_ > 1;
- $_[0]->{_create_args}
-}
+ if(!exists $args->{init_arg}){
+ $args->{init_arg} = $name;
+ }
-sub inlined_name {
- my $self = shift;
- my $name = $self->name;
- my $key = "'" . $name . "'";
- return $key;
-}
+ # 'required' requires eigher 'init_arg', 'builder', or 'default'
+ my $can_be_required = defined( $args->{init_arg} );
-sub generate_accessor {
- my $attribute = shift;
-
- my $name = $attribute->name;
- my $default = $attribute->default;
- my $constraint = $attribute->find_type_constraint;
- my $builder = $attribute->builder;
- my $trigger = $attribute->trigger;
- my $is_weak = $attribute->is_weak_ref;
- my $should_deref = $attribute->should_auto_deref;
- my $should_coerce = $attribute->should_coerce;
-
- my $self = '$_[0]';
- my $key = $attribute->inlined_name;
-
- my $accessor = "sub {\n";
- if ($attribute->_is_metadata eq 'rw') {
- $accessor .= 'if (@_ >= 2) {' . "\n";
-
- my $value = '$_[1]';
-
- if ($constraint) {
- $accessor .= 'my $val = ';
- if ($should_coerce) {
- $accessor .= 'Mouse::Util::TypeConstraints->typecast_constraints("'.$attribute->associated_class->name.'", $attribute->{find_type_constraint}, $attribute->{type_constraint}, '.$value.');';
- } else {
- $accessor .= $value.';';
- }
- $accessor .= 'local $_ = $val;';
- $accessor .= '
- unless ($constraint->()) {
- $attribute->verify_type_constraint_error($name, $_, $attribute->type_constraint);
- }' . "\n";
- $value = '$val';
+ if(exists $args->{builder}){
+ # XXX:
+ # Moose refuses a CODE ref builder, but Mouse doesn't for backward compatibility
+ # This feature will be changed in a future. (gfx)
+ $class->throw_error('builder must be a defined scalar value which is a method name')
+ #if ref $args->{builder} || !defined $args->{builder};
+ if !defined $args->{builder};
+
+ $can_be_required++;
+ }
+ elsif(exists $args->{default}){
+ if(ref $args->{default} && ref($args->{default}) ne 'CODE'){
+ $class->throw_error("References are not allowed as default values, you must "
+ . "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])");
}
+ $can_be_required++;
+ }
- # if there's nothing left to do for the attribute we can return during
- # this setter
- $accessor .= 'return ' if !$is_weak && !$trigger && !$should_deref;
+ if( $args->{required} && !$can_be_required ) {
+ $class->throw_error("You cannot have a required attribute ($name) without a default, builder, or an init_arg");
+ }
- $accessor .= $self.'->{'.$key.'} = '.$value.';' . "\n";
+ # taken from Mouse::Meta::Attribute->new and _process_args->
- if ($is_weak) {
- $accessor .= 'Scalar::Util::weaken('.$self.'->{'.$key.'}) if ref('.$self.'->{'.$key.'});' . "\n";
- }
+ if(exists $args->{is}){
+ my $is = $args->{is};
- if ($trigger) {
- $accessor .= '$trigger->('.$self.', '.$value.', $attribute);' . "\n";
+ if($is eq 'ro'){
+ $args->{reader} ||= $name;
+ }
+ elsif($is eq 'rw'){
+ if(exists $args->{writer}){
+ $args->{reader} ||= $name;
+ }
+ else{
+ $args->{accessor} ||= $name;
+ }
+ }
+ elsif($is eq 'bare'){
+ # do nothing, but don't complain (later) about missing methods
}
+ else{
+ $is = 'undef' if !defined $is;
+ $class->throw_error("I do not understand this option (is => $is) on attribute ($name)");
+ }
+ }
- $accessor .= "}\n";
+ my $tc;
+ if(exists $args->{isa}){
+ $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_isa_type_constraint($args->{isa});
}
- else {
- $accessor .= 'confess "Cannot assign a value to a read-only accessor" if scalar(@_) >= 2;' . "\n";
+ elsif(exists $args->{does}){
+ # TODO
+ # $args->{type_constraint} = Mouse::Util::TypeConstraints::find_or_create_does_type_constraint($args->{does});
}
+ $tc = $args->{type_constraint};
+
+ if($args->{coerce}){
+ defined($tc)
+ || $class->throw_error("You cannot have coercion without specifying a type constraint on attribute ($name)");
- # XXX - edit by lestrrat 20090304:
- # I couldn't quite tell why this happened, but I encountered a case
- # where the default value was not set. In introspecting the resulting
- # $accessor string, I realized that there was no default handling code.
- # which led me to adding "|| $attribute->has_default" below.
- # Tests passed, so I hope everything will be ok
- if ($attribute->is_lazy || $attribute->has_default) {
- $accessor .= $self.'->{'.$key.'} = ';
-
- $accessor .= $attribute->has_builder
- ? $self.'->$builder'
- : ref($default) eq 'CODE'
- ? '$default->('.$self.')'
- : '$default';
- $accessor .= ' if !exists '.$self.'->{'.$key.'};' . "\n";
+ $args->{weak_ref}
+ && $class->throw_error("You cannot have a weak reference to a coerced value on attribute ($name)");
}
- if ($should_deref) {
- my $type_constraint = $attribute->type_constraint;
- if (!ref($type_constraint) && $type_constraint eq 'ArrayRef') {
- $accessor .= 'if (wantarray) {
- return @{ '.$self.'->{'.$key.'} || [] };
- }';
+ if ($args->{lazy_build}) {
+ exists($args->{default})
+ && $class->throw_error("You can not use lazy_build and default for the same attribute ($name)");
+
+ $args->{lazy} = 1;
+ $args->{builder} ||= "_build_${name}";
+ if ($name =~ /^_/) {
+ $args->{clearer} ||= "_clear${name}";
+ $args->{predicate} ||= "_has${name}";
}
else {
- $accessor .= 'if (wantarray) {
- return %{ '.$self.'->{'.$key.'} || {} };
- }';
+ $args->{clearer} ||= "clear_${name}";
+ $args->{predicate} ||= "has_${name}";
}
}
- $accessor .= 'return '.$self.'->{'.$key.'};
- }';
+ if ($args->{auto_deref}) {
+ defined($tc)
+ || $class->throw_error("You cannot auto-dereference without specifying a type constraint on attribute ($name)");
- my $sub = eval $accessor;
- confess $@ if $@;
- return $sub;
-}
+ ( $tc->is_a_type_of('ArrayRef') || $tc->is_a_type_of('HashRef') )
+ || $class->throw_error("You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)");
+ }
-sub generate_predicate {
- my $attribute = shift;
- my $key = $attribute->inlined_name;
+ if (exists $args->{trigger}) {
+ ('CODE' eq ref $args->{trigger})
+ || $class->throw_error("Trigger must be a CODE ref on attribute ($name)");
+ }
- my $predicate = 'sub { exists($_[0]->{'.$key.'}) }';
+ if ($args->{lazy}) {
+ (exists $args->{default} || defined $args->{builder})
+ || $class->throw_error("You cannot have lazy attribute ($name) without specifying a default value for it");
+ }
- my $sub = eval $predicate;
- confess $@ if $@;
- return $sub;
+ return;
}
-sub generate_clearer {
- my $attribute = shift;
- my $key = $attribute->inlined_name;
+sub new {
+ my $class = shift;
+ my $name = shift;
+
+ my %args = (@_ == 1) ? %{ $_[0] } : @_;
+
+ $class->_process_options($name, \%args);
- my $clearer = 'sub { delete($_[0]->{'.$key.'}) }';
+ $args{name} = $name;
+
+ my $self = bless \%args, $class;
+
+ # extra attributes
+ if($class ne __PACKAGE__){
+ $class->meta->_initialize_object($self, \%args);
+ }
+
+# XXX: there is no fast way to check attribute validity
+# my @bad = ...;
+# if(@bad){
+# @bad = sort @bad;
+# Carp::cluck("Found unknown argument(s) passed to '$name' attribute constructor in '$class': @bad");
+# }
- my $sub = eval $clearer;
- confess $@ if $@;
- return $sub;
+ return $self;
}
-sub generate_handles {
- my $attribute = shift;
- my $reader = $attribute->name;
- my %handles = $attribute->_canonicalize_handles($attribute->handles);
+# readers
+
+sub name { $_[0]->{name} }
+sub associated_class { $_[0]->{associated_class} }
+
+sub accessor { $_[0]->{accessor} }
+sub reader { $_[0]->{reader} }
+sub writer { $_[0]->{writer} }
+sub predicate { $_[0]->{predicate} }
+sub clearer { $_[0]->{clearer} }
+sub handles { $_[0]->{handles} }
+
+sub _is_metadata { $_[0]->{is} }
+sub is_required { $_[0]->{required} }
+sub default { $_[0]->{default} }
+sub is_lazy { $_[0]->{lazy} }
+sub is_lazy_build { $_[0]->{lazy_build} }
+sub is_weak_ref { $_[0]->{weak_ref} }
+sub init_arg { $_[0]->{init_arg} }
+sub type_constraint { $_[0]->{type_constraint} }
+
+sub trigger { $_[0]->{trigger} }
+sub builder { $_[0]->{builder} }
+sub should_auto_deref { $_[0]->{auto_deref} }
+sub should_coerce { $_[0]->{coerce} }
- my %method_map;
+sub get_read_method { $_[0]->{reader} || $_[0]->{accessor} }
+sub get_write_method { $_[0]->{writer} || $_[0]->{accessor} }
- for my $local_method (keys %handles) {
- my $remote_method = $handles{$local_method};
+# predicates
- my $method = 'sub {
- my $self = shift;
- $self->'.$reader.'->'.$remote_method.'(@_)
- }';
+sub has_accessor { exists $_[0]->{accessor} }
+sub has_reader { exists $_[0]->{reader} }
+sub has_writer { exists $_[0]->{writer} }
+sub has_predicate { exists $_[0]->{predicate} }
+sub has_clearer { exists $_[0]->{clearer} }
+sub has_handles { exists $_[0]->{handles} }
- $method_map{$local_method} = eval $method;
- confess $@ if $@;
- }
+sub has_default { exists $_[0]->{default} }
+sub has_type_constraint { exists $_[0]->{type_constraint} }
+sub has_trigger { exists $_[0]->{trigger} }
+sub has_builder { exists $_[0]->{builder} }
- return \%method_map;
+sub has_read_method { exists $_[0]->{reader} || exists $_[0]->{accessor} }
+sub has_write_method { exists $_[0]->{writer} || exists $_[0]->{accessor} }
+
+sub _create_args {
+ $_[0]->{_create_args} = $_[1] if @_ > 1;
+ $_[0]->{_create_args}
}
-sub create {
- my ($self, $class, $name, %args) = @_;
+sub interpolate_class{
+ my($class, $name, $args) = @_;
- $args{name} = $name;
- $args{associated_class} = $class;
-
- %args = $self->canonicalize_args($name, %args);
- $self->validate_args($name, \%args);
-
- $args{should_coerce} = delete $args{coerce}
- if exists $args{coerce};
-
- if (exists $args{isa}) {
- confess "Mouse does not yet support parameterized types (rt.cpan.org #39795)"
- if $args{isa} =~ /\[.*\]/;
-
- my $type_constraint = delete $args{isa};
- $type_constraint =~ s/\s//g;
- my @type_constraints = split /\|/, $type_constraint;
-
- my $code;
- my $optimized_constraints = Mouse::Util::TypeConstraints->optimized_constraints;
- if (@type_constraints == 1) {
- $code = $optimized_constraints->{$type_constraints[0]} ||
- sub { Scalar::Util::blessed($_) && $_->isa($type_constraints[0]) };
- $args{type_constraint} = $type_constraints[0];
- } else {
- my @code_list = map {
- my $type = $_;
- $optimized_constraints->{$type} ||
- sub { Scalar::Util::blessed($_) && $_->isa($type) }
- } @type_constraints;
- $code = sub {
- for my $code (@code_list) {
- return 1 if $code->();
- }
- return 0;
- };
- $args{type_constraint} = \@type_constraints;
- }
- $args{find_type_constraint} = $code;
+ if(my $metaclass = delete $args->{metaclass}){
+ $class = Mouse::Util::resolve_metaclass_alias( Attribute => $metaclass );
}
- my $attribute = $self->new($name, %args);
+ my @traits;
+ if(my $traits_ref = delete $args->{traits}){
- $attribute->_create_args(\%args);
+ for (my $i = 0; $i < @{$traits_ref}; $i++) {
+ my $trait = Mouse::Util::resolve_metaclass_alias(Attribute => $traits_ref->[$i], trait => 1);
- $class->add_attribute($attribute);
+ next if $class->does($trait);
- # install an accessor
- if ($attribute->_is_metadata eq 'rw' || $attribute->_is_metadata eq 'ro') {
- my $accessor = $attribute->generate_accessor;
- $class->add_method($name => $accessor);
- }
+ push @traits, $trait;
- for my $method (qw/predicate clearer/) {
- my $predicate = "has_$method";
- if ($attribute->$predicate) {
- my $generator = "generate_$method";
- my $coderef = $attribute->$generator;
- $class->add_method($attribute->$method => $coderef);
+ # are there options?
+ push @traits, $traits_ref->[++$i]
+ if ref($traits_ref->[$i+1]);
}
- }
- if ($attribute->has_handles) {
- my $method_map = $attribute->generate_handles;
- for my $method_name (keys %$method_map) {
- $class->add_method($method_name => $method_map->{$method_name});
+ if (@traits) {
+ $class = Mouse::Meta::Class->create_anon_class(
+ superclasses => [ $class ],
+ roles => \@traits,
+ cache => 1,
+ )->name;
}
}
- return $attribute;
+ return( $class, @traits );
}
-sub canonicalize_args {
- my $self = shift;
- my $name = shift;
- my %args = @_;
+sub canonicalize_args{
+ my ($self, $name, %args) = @_;
- if ($args{lazy_build}) {
- $args{lazy} = 1;
- $args{required} = 1;
- $args{builder} = "_build_${name}"
- if !exists($args{builder});
- if ($name =~ /^_/) {
- $args{clearer} = "_clear${name}" if !exists($args{clearer});
- $args{predicate} = "_has${name}" if !exists($args{predicate});
- }
- else {
- $args{clearer} = "clear_${name}" if !exists($args{clearer});
- $args{predicate} = "has_${name}" if !exists($args{predicate});
- }
- }
+ Carp::cluck("$self->canonicalize_args has been deprecated."
+ . "Use \$self->_process_options instead.")
+ if _MOUSE_VERBOSE;
return %args;
}
-sub validate_args {
- my $self = shift;
- my $name = shift;
- my $args = shift;
-
- confess "You can not use lazy_build and default for the same attribute ($name)"
- if $args->{lazy_build} && exists $args->{default};
+sub create {
+ my ($self, $class, $name, %args) = @_;
- confess "You cannot have lazy attribute ($name) without specifying a default value for it"
- if $args->{lazy}
- && !exists($args->{default})
- && !exists($args->{builder});
+ Carp::cluck("$self->create has been deprecated."
+ . "Use \$meta->add_attribute and \$attr->install_accessors instead.")
+ if _MOUSE_VERBOSE;
- confess "References are not allowed as default values, you must wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])"
- if ref($args->{default})
- && ref($args->{default}) ne 'CODE';
+ # noop
+ return $self;
+}
- confess "You cannot auto-dereference without specifying a type constraint on attribute ($name)"
- if $args->{auto_deref} && !exists($args->{isa});
+sub _coerce_and_verify {
+ my($self, $value, $instance) = @_;
- confess "You cannot auto-dereference anything other than a ArrayRef or HashRef on attribute ($name)"
- if $args->{auto_deref}
- && $args->{isa} ne 'ArrayRef'
- && $args->{isa} ne 'HashRef';
+ my $type_constraint = $self->{type_constraint};
- if ($args->{trigger}) {
- if (ref($args->{trigger}) eq 'HASH') {
- Carp::carp "HASH-based form of trigger has been removed. Only the coderef form of triggers are now supported.";
- }
+ return $value if !$type_constraint;
- confess "Trigger must be a CODE ref on attribute ($name)"
- if ref($args->{trigger}) ne 'CODE';
+ if ($self->should_coerce && $type_constraint->has_coercion) {
+ $value = $type_constraint->coerce($value);
}
- return 1;
+ return $value if $type_constraint->check($value);
+
+ $self->verify_against_type_constraint($value);
+
+ return $value;
}
sub verify_against_type_constraint {
- return 1 unless $_[0]->{type_constraint};
+ my ($self, $value) = @_;
- local $_ = $_[1];
- return 1 if $_[0]->{find_type_constraint}->($_);
+ my $type_constraint = $self->{type_constraint};
+ return 1 if !$type_constraint;;
+ return 1 if $type_constraint->check($value);
- my $self = shift;
- $self->verify_type_constraint_error($self->name, $_, $self->type_constraint);
+ $self->verify_type_constraint_error($self->name, $value, $type_constraint);
}
sub verify_type_constraint_error {
my($self, $name, $value, $type) = @_;
- $type = ref($type) eq 'ARRAY' ? join '|', @{ $type } : $type;
- my $display = defined($_) ? overload::StrVal($_) : 'undef';
- Carp::confess("Attribute ($name) does not pass the type constraint because: Validation failed for \'$type\' failed with value $display");
+ $self->throw_error("Attribute ($name) does not pass the type constraint because: " . $type->get_message($value));
}
sub coerce_constraint { ## my($self, $value) = @_;
my $type = $_[0]->{type_constraint}
or return $_[1];
- return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $_[0]->find_type_constraint, $type, $_[1]);
+
+ Carp::cluck("coerce_constraint() has been deprecated, which was an internal utility anyway");
+
+ return Mouse::Util::TypeConstraints->typecast_constraints($_[0]->associated_class->name, $type, $_[1]);
}
sub _canonicalize_handles {
return map { $_ => $_ } @$handles;
}
else {
- confess "Unable to canonicalize the 'handles' option with $handles";
+ $self->throw_error("Unable to canonicalize the 'handles' option with $handles");
}
}
+sub clone_and_inherit_options{
+ my $self = shift;
+ my $name = shift;
+
+ return ref($self)->new($name, %{$self}, (@_ == 1) ? %{$_[0]} : @_);
+}
+
sub clone_parent {
my $self = shift;
my $class = shift;
my $name = shift;
my %args = ($self->get_parent_args($class, $name), @_);
- $self->create($class, $name, %args);
+ Carp::cluck("$self->clone_parent has been deprecated."
+ . "Use \$meta->add_attribute and \$attr->install_accessors instead.")
+ if _MOUSE_VERBOSE;
+
+ $self->clone_and_inherited_args($class, $name, %args);
}
sub get_parent_args {
return %{ $super_attr->_create_args };
}
- confess "Could not find an attribute by the name of '$name' to inherit from";
+ $self->throw_error("Could not find an attribute by the name of '$name' to inherit from");
+}
+
+sub associate_method{
+ my ($attribute, $method) = @_;
+ $attribute->{associated_methods}++;
+ return;
+}
+
+sub install_accessors{
+ my($attribute) = @_;
+
+ my $metaclass = $attribute->{associated_class};
+
+ foreach my $type(qw(accessor reader writer predicate clearer handles)){
+ if(exists $attribute->{$type}){
+ my $installer = '_install_' . $type;
+
+ Mouse::Meta::Method::Accessor->$installer($attribute, $attribute->{$type}, $metaclass);
+
+ $attribute->{associated_methods}++;
+ }
+ }
+
+ if($attribute->can('create') != \&create){
+ # backword compatibility
+ $attribute->create($metaclass, $attribute->name, %{$attribute});
+ }
+
+ return;
+}
+
+sub throw_error{
+ my $self = shift;
+
+ my $metaclass = (ref $self && $self->associated_class) || 'Mouse::Meta::Class';
+ $metaclass->throw_error(@_, depth => 1);
}
1;
=head1 NAME
-Mouse::Meta::Attribute - attribute metaclass
+Mouse::Meta::Attribute - The Mouse attribute metaclass
=head1 METHODS
-=head2 new %args -> Mouse::Meta::Attribute
+=head2 C<< new(%options) -> Mouse::Meta::Attribute >>
Instantiates a new Mouse::Meta::Attribute. Does nothing else.
-=head2 create OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
+It adds the following options to the constructor:
-Creates a new attribute in OwnerClass. Accessors and helper methods are
-installed. Some error checking is done.
+=over 4
-=head2 name -> AttributeName
+=item C<< is => 'ro', 'rw', 'bare' >>
-=head2 associated_class -> OwnerClass
+This provides a shorthand for specifying the C<reader>, C<writer>, or
+C<accessor> names. If the attribute is read-only ('ro') then it will
+have a C<reader> method with the same attribute as the name.
-=head2 is_required -> Bool
+If it is read-write ('rw') then it will have an C<accessor> method
+with the same name. If you provide an explicit C<writer> for a
+read-write attribute, then you will have a C<reader> with the same
+name as the attribute, and a C<writer> with the name you provided.
-=head2 default -> Item
+Use 'bare' when you are deliberately not installing any methods
+(accessor, reader, etc.) associated with this attribute; otherwise,
+Moose will issue a deprecation warning when this attribute is added to a
+metaclass.
-=head2 has_default -> Bool
+=item C<< isa => Type >>
-=head2 is_lazy -> Bool
+This option accepts a type. The type can be a string, which should be
+a type name. If the type name is unknown, it is assumed to be a class
+name.
-=head2 predicate -> MethodName | Undef
+This option can also accept a L<Moose::Meta::TypeConstraint> object.
-=head2 has_predicate -> Bool
+If you I<also> provide a C<does> option, then your C<isa> option must
+be a class name, and that class must do the role specified with
+C<does>.
-=head2 clearer -> MethodName | Undef
+=item C<< does => Role >>
-=head2 has_clearer -> Bool
+This is short-hand for saying that the attribute's type must be an
+object which does the named role.
-=head2 handles -> { LocalName => RemoteName }
+B<This option is not yet supported.>
-=head2 has_handles -> Bool
+=item C<< coerce => Bool >>
-=head2 is_weak_ref -> Bool
+This option is only valid for objects with a type constraint
+(C<isa>). If this is true, then coercions will be applied whenever
+this attribute is set.
-=head2 init_arg -> Str
+You can make both this and the C<weak_ref> option true.
-=head2 type_constraint -> Str
+=item C<< trigger => CodeRef >>
-=head2 has_type_constraint -> Bool
+This option accepts a subroutine reference, which will be called after
+the attribute is set.
-=head2 trigger => CODE | Undef
+=item C<< required => Bool >>
-=head2 has_trigger -> Bool
+An attribute which is required must be provided to the constructor. An
+attribute which is required can also have a C<default> or C<builder>,
+which will satisfy its required-ness.
-=head2 builder => MethodName | Undef
+A required attribute must have a C<default>, C<builder> or a
+non-C<undef> C<init_arg>
-=head2 has_builder -> Bool
+=item C<< lazy => Bool >>
-=head2 is_lazy_build => Bool
+A lazy attribute must have a C<default> or C<builder>. When an
+attribute is lazy, the default value will not be calculated until the
+attribute is read.
-=head2 should_auto_deref -> Bool
+=item C<< weak_ref => Bool >>
-Informational methods.
+If this is true, the attribute's value will be stored as a weak
+reference.
-=head2 generate_accessor -> CODE
+=item C<< auto_deref => Bool >>
-Creates a new code reference for the attribute's accessor.
+If this is true, then the reader will dereference the value when it is
+called. The attribute must have a type constraint which defines the
+attribute as an array or hash reference.
-=head2 generate_predicate -> CODE
+=item C<< lazy_build => Bool >>
-Creates a new code reference for the attribute's predicate.
+Setting this to true makes the attribute lazy and provides a number of
+default methods.
-=head2 generate_clearer -> CODE
+ has 'size' => (
+ is => 'ro',
+ lazy_build => 1,
+ );
-Creates a new code reference for the attribute's clearer.
+is equivalent to this:
-=head2 generate_handles -> { MethodName => CODE }
+ has 'size' => (
+ is => 'ro',
+ lazy => 1,
+ builder => '_build_size',
+ clearer => 'clear_size',
+ predicate => 'has_size',
+ );
-Creates a new code reference for each of the attribute's handles methods.
+=back
-=head2 find_type_constraint -> CODE
+=head2 C<< associate_method(Method) >>
-Returns a code reference which can be used to check that a given value passes
-this attribute's type constraint;
+Associates a method with the attribute. Typically, this is called internally
+when an attribute generates its accessors.
-=head2 verify_against_type_constraint Item -> 1 | ERROR
-
-Checks that the given value passes this attribute's type constraint. Returns 1
-on success, otherwise C<confess>es.
+Currently the argument I<Method> is ignored in Mouse.
-=head2 canonicalize_args Name, %args -> %args
+=head2 C<< verify_against_type_constraint(Item) -> TRUE | ERROR >>
-Canonicalizes some arguments to create. In particular, C<lazy_build> is
-canonicalized into C<lazy>, C<builder>, etc.
-
-=head2 validate_args Name, \%args -> 1 | ERROR
-
-Checks that the arguments to create the attribute (ie those specified by
-C<has>) are valid.
+Checks that the given value passes this attribute's type constraint. Returns C<true>
+on success, otherwise C<confess>es.
-=head2 clone_parent OwnerClass, AttributeName, %args -> Mouse::Meta::Attribute
+=head2 C<< clone_and_inherit_options(options) -> Mouse::Meta::Attribute >>
-Creates a new attribute in OwnerClass, inheriting options from parent classes.
+Creates a new attribute in the owner class, inheriting options from parent classes.
Accessors and helper methods are installed. Some error checking is done.
-=head2 get_parent_args OwnerClass, AttributeName -> Hash
+=head1 SEE ALSO
+
+L<Moose::Meta::Attribute>
-Returns the options that the parent class of C<OwnerClass> used for attribute
-C<AttributeName>.
+L<Class::MOP::Attribute>
=cut