use strict;
use warnings;
-use Scalar::Util 'weaken', 'reftype';
+use Scalar::Util 'blessed', 'weaken', 'reftype';
use Carp 'confess';
+use Sub::Name 'subname';
+use overload ();
-our $VERSION = '0.02';
+our $VERSION = '0.22';
+our $AUTHORITY = 'cpan:STEVAN';
+
+use Moose::Meta::Method::Accessor;
+use Moose::Util::TypeConstraints ();
use base 'Class::MOP::Attribute';
-__PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce'));
-__PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' ));
+# options which are not directly used
+# but we store them for metadata purposes
+__PACKAGE__->meta->add_attribute('isa' => (reader => '_isa_metadata'));
+__PACKAGE__->meta->add_attribute('does' => (reader => '_does_metadata'));
+__PACKAGE__->meta->add_attribute('is' => (reader => '_is_metadata'));
+
+# these are actual options for the attrs
+__PACKAGE__->meta->add_attribute('required' => (reader => 'is_required' ));
+__PACKAGE__->meta->add_attribute('lazy' => (reader => 'is_lazy' ));
+__PACKAGE__->meta->add_attribute('lazy_build' => (reader => 'is_lazy_build' ));
+__PACKAGE__->meta->add_attribute('coerce' => (reader => 'should_coerce' ));
+__PACKAGE__->meta->add_attribute('weak_ref' => (reader => 'is_weak_ref' ));
+__PACKAGE__->meta->add_attribute('auto_deref' => (reader => 'should_auto_deref'));
__PACKAGE__->meta->add_attribute('type_constraint' => (
reader => 'type_constraint',
predicate => 'has_type_constraint',
));
+__PACKAGE__->meta->add_attribute('trigger' => (
+ reader => 'trigger',
+ predicate => 'has_trigger',
+));
+__PACKAGE__->meta->add_attribute('handles' => (
+ reader => 'handles',
+ predicate => 'has_handles',
+));
+__PACKAGE__->meta->add_attribute('documentation' => (
+ reader => 'documentation',
+ predicate => 'has_documentation',
+));
-__PACKAGE__->meta->add_before_method_modifier('new' => sub {
- my (undef, undef, %options) = @_;
- if (exists $options{coerce} && $options{coerce}) {
- (exists $options{type_constraint})
- || confess "You cannot have coercion without specifying a type constraint";
+sub new {
+ my ($class, $name, %options) = @_;
+ $class->_process_options($name, \%options);
+ return $class->SUPER::new($name, %options);
+}
+
+sub clone_and_inherit_options {
+ my ($self, %options) = @_;
+ # you can change default, required, coerce, documentation and lazy
+ my %actual_options;
+ foreach my $legal_option (qw(default coerce required documentation lazy)) {
+ if (exists $options{$legal_option}) {
+ $actual_options{$legal_option} = $options{$legal_option};
+ delete $options{$legal_option};
+ }
+ }
+
+ # handles can only be added, not changed
+ if ($options{handles}) {
+ confess "You can only add the 'handles' option, you cannot change it"
+ if $self->has_handles;
+ $actual_options{handles} = $options{handles};
+ delete $options{handles};
+ }
+
+ # handles can only be added, not changed
+ if ($options{builder}) {
+ confess "You can only add the 'builder' option, you cannot change it"
+ if $self->has_builder;
+ $actual_options{builder} = $options{builder};
+ delete $options{builder};
+ }
+
+ # isa can be changed, but only if the
+ # new type is a subtype
+ if ($options{isa}) {
+ my $type_constraint;
+ if (blessed($options{isa}) && $options{isa}->isa('Moose::Meta::TypeConstraint')) {
+ $type_constraint = $options{isa};
+ }
+ else {
+ $type_constraint = Moose::Util::TypeConstraints::find_or_create_type_constraint(
+ $options{isa}
+ );
+ (defined $type_constraint)
+ || confess "Could not find the type constraint '" . $options{isa} . "'";
+ }
+ # NOTE:
+ # check here to see if the new type
+ # is a subtype of the old one
+ ($type_constraint->is_subtype_of($self->type_constraint->name))
+ || confess "New type constraint setting must be a subtype of inherited one"
+ # iff we have a type constraint that is ...
+ if $self->has_type_constraint;
+ # then we use it :)
+ $actual_options{type_constraint} = $type_constraint;
+ delete $options{isa};
+ }
+ (scalar keys %options == 0)
+ || confess "Illegal inherited options => (" . (join ', ' => keys %options) . ")";
+ $self->clone(%actual_options);
+}
+
+sub _process_options {
+ my ($class, $name, $options) = @_;
+
+ if (exists $options->{is}) {
+ if ($options->{is} eq 'ro') {
+ $options->{reader} ||= $name;
+ (!exists $options->{trigger})
+ || confess "Cannot have a trigger on a read-only attribute";
+ }
+ elsif ($options->{is} eq 'rw') {
+ $options->{accessor} = $name;
+ ((reftype($options->{trigger}) || '') eq 'CODE')
+ || confess "Trigger must be a CODE ref"
+ if exists $options->{trigger};
+ }
+ else {
+ confess "I do not understand this option (is => " . $options->{is} . ")"
+ }
+ }
+
+ if (exists $options->{isa}) {
+ if (exists $options->{does}) {
+ if (eval { $options->{isa}->can('does') }) {
+ ($options->{isa}->does($options->{does}))
+ || confess "Cannot have an isa option and a does option if the isa does not do the does";
+ }
+ else {
+ confess "Cannot have an isa option which cannot ->does()";
+ }
+ }
+
+ # allow for anon-subtypes here ...
+ if (blessed($options->{isa}) && $options->{isa}->isa('Moose::Meta::TypeConstraint')) {
+ $options->{type_constraint} = $options->{isa};
+ }
+ else {
+ $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint(
+ $options->{isa} => {
+ parent => Moose::Util::TypeConstraints::find_type_constraint('Object'),
+ constraint => sub { $_[0]->isa($options->{isa}) }
+ }
+ );
+ }
+ }
+ elsif (exists $options->{does}) {
+ # allow for anon-subtypes here ...
+ if (blessed($options->{does}) && $options->{does}->isa('Moose::Meta::TypeConstraint')) {
+ $options->{type_constraint} = $options->{does};
+ }
+ else {
+ $options->{type_constraint} = Moose::Util::TypeConstraints::find_or_create_type_constraint(
+ $options->{does} => {
+ parent => Moose::Util::TypeConstraints::find_type_constraint('Role'),
+ constraint => sub {
+ Moose::Util::does_role($_[0], $options->{does})
+ }
+ }
+ );
+ }
+ }
+
+ if (exists $options->{coerce} && $options->{coerce}) {
+ (exists $options->{type_constraint})
+ || confess "You cannot have coercion without specifying a type constraint";
confess "You cannot have a weak reference to a coerced value"
- if $options{weak_ref};
- }
-});
-
-sub generate_accessor_method {
- my ($self, $attr_name) = @_;
- if ($self->has_type_constraint) {
- if ($self->is_weak_ref) {
- return sub {
- if (scalar(@_) == 2) {
- (defined $self->type_constraint->check($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$_[1]'"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- }
- $_[0]->{$attr_name};
- };
- }
- else {
- if ($self->should_coerce) {
- return sub {
- if (scalar(@_) == 2) {
- my $val = $self->type_constraint->coercion->coerce($_[1]);
- (defined $self->type_constraint->check($val))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$val'"
- if defined $val;
- $_[0]->{$attr_name} = $val;
- }
- $_[0]->{$attr_name};
- };
- }
- else {
- return sub {
- if (scalar(@_) == 2) {
- (defined $self->type_constraint->check($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$_[1]'"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- }
- $_[0]->{$attr_name};
- };
- }
- }
- }
- else {
- if ($self->is_weak_ref) {
- return sub {
- if (scalar(@_) == 2) {
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- }
- $_[0]->{$attr_name};
- };
- }
- else {
- sub {
- $_[0]->{$attr_name} = $_[1] if scalar(@_) == 2;
- $_[0]->{$attr_name};
- };
- }
- }
+ if $options->{weak_ref};
+ }
+
+ if (exists $options->{auto_deref} && $options->{auto_deref}) {
+ (exists $options->{type_constraint})
+ || confess "You cannot auto-dereference without specifying a type constraint";
+ ($options->{type_constraint}->is_a_type_of('ArrayRef') ||
+ $options->{type_constraint}->is_a_type_of('HashRef'))
+ || confess "You cannot auto-dereference anything other than a ArrayRef or HashRef";
+ }
+
+ if (exists $options->{lazy_build} && $options->{lazy_build} == 1) {
+ confess("You can not use lazy_build and default for the same attribute")
+ if exists $options->{default};
+ $options->{lazy} = 1;
+ $options->{required} = 1;
+ $options->{builder} ||= "_build_${name}";
+ if ($name =~ /^_/) {
+ $options->{clearer} ||= "_clear${name}";
+ $options->{predicate} ||= "_has${name}";
+ }
+ else {
+ $options->{clearer} ||= "clear_${name}";
+ $options->{predicate} ||= "has_${name}";
+ }
+ }
+
+ if (exists $options->{lazy} && $options->{lazy}) {
+ (exists $options->{default} || defined $options->{builder} )
+ || confess "You cannot have lazy attribute without specifying a default value for it";
+ }
+
+ if ( $options->{required} && !( ( !exists $options->{init_arg} || defined $options->{init_arg} ) || exists $options->{default} || defined $options->{builder} ) ) {
+ confess "You cannot have a required attribute without a default, builder, or an init_arg";
+ }
+
}
-sub generate_writer_method {
- my ($self, $attr_name) = @_;
- if ($self->has_type_constraint) {
- if ($self->is_weak_ref) {
- return sub {
- (defined $self->type_constraint->check($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$_[1]'"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- };
- }
- else {
- if ($self->should_coerce) {
- return sub {
- my $val = $self->type_constraint->coercion->coerce($_[1]);
- (defined $self->type_constraint->check($val))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$val'"
- if defined $val;
- $_[0]->{$attr_name} = $val;
- };
- }
- else {
- return sub {
- (defined $self->type_constraint->check($_[1]))
- || confess "Attribute ($attr_name) does not pass the type contraint with '$_[1]'"
- if defined $_[1];
- $_[0]->{$attr_name} = $_[1];
- };
- }
- }
- }
- else {
- if ($self->is_weak_ref) {
- return sub {
- $_[0]->{$attr_name} = $_[1];
- weaken($_[0]->{$attr_name});
- };
- }
- else {
- return sub { $_[0]->{$attr_name} = $_[1] };
- }
- }
+sub initialize_instance_slot {
+ my ($self, $meta_instance, $instance, $params) = @_;
+ my $init_arg = $self->init_arg();
+ # try to fetch the init arg from the %params ...
+
+ my $val;
+ my $value_is_set;
+ if ( defined($init_arg) and exists $params->{$init_arg}) {
+ $val = $params->{$init_arg};
+ $value_is_set = 1;
+ }
+ else {
+ # skip it if it's lazy
+ return if $self->is_lazy;
+ # and die if it's required and doesn't have a default value
+ confess "Attribute (" . $self->name . ") is required"
+ if $self->is_required && !$self->has_default && !$self->has_builder;
+
+ # if nothing was in the %params, we can use the
+ # attribute's default value (if it has one)
+ if ($self->has_default) {
+ $val = $self->default($instance);
+ $value_is_set = 1;
+ }
+ elsif ($self->has_builder) {
+ if (my $builder = $instance->can($self->builder)){
+ $val = $instance->$builder;
+ $value_is_set = 1;
+ }
+ else {
+ confess(blessed($instance)." does not support builder method '".$self->builder."' for attribute '" . $self->name . "'");
+ }
+ }
+ }
+
+ return unless $value_is_set;
+
+ if ($self->has_type_constraint) {
+ my $type_constraint = $self->type_constraint;
+ if ($self->should_coerce && $type_constraint->has_coercion) {
+ $val = $type_constraint->coerce($val);
+ }
+ $type_constraint->check($val)
+ || confess "Attribute ("
+ . $self->name
+ . ") does not pass the type constraint because: "
+ . $type_constraint->get_message($val);
+ }
+
+ $self->set_initial_value($instance, $val);
+ $meta_instance->weaken_slot_value($instance, $self->name)
+ if ref $val && $self->is_weak_ref;
}
-sub generate_reader_method {
- my ($self, $attr_name) = @_;
- sub {
- confess "Cannot assign a value to a read-only accessor" if @_ > 1;
- $_[0]->{$attr_name}
- };
+## Slot management
+
+# FIXME:
+# this duplicates too much code from
+# Class::MOP::Attribute, we need to
+# refactor these bits eventually.
+# - SL
+sub _set_initial_slot_value {
+ my ($self, $meta_instance, $instance, $value) = @_;
+
+ my $slot_name = $self->name;
+
+ return $meta_instance->set_slot_value($instance, $slot_name, $value)
+ unless $self->has_initializer;
+
+ my ($type_constraint, $can_coerce);
+ if ($self->has_type_constraint) {
+ $type_constraint = $self->type_constraint;
+ $can_coerce = ($self->should_coerce && $type_constraint->has_coercion);
+ }
+
+ my $callback = sub {
+ my $val = shift;
+ if ($type_constraint) {
+ $val = $type_constraint->coerce($val)
+ if $can_coerce;
+ $type_constraint->check($val)
+ || confess "Attribute ("
+ . $slot_name
+ . ") does not pass the type constraint because: "
+ . $type_constraint->get_message($val);
+ }
+ $meta_instance->set_slot_value($instance, $slot_name, $val);
+ };
+
+ my $initializer = $self->initializer;
+
+ # most things will just want to set a value, so make it first arg
+ $instance->$initializer($value, $callback, $self);
+}
+
+sub set_value {
+ my ($self, $instance, $value) = @_;
+
+ my $attr_name = $self->name;
+
+ if ($self->is_required) {
+ defined($value)
+ || confess "Attribute ($attr_name) is required, so cannot be set to undef";
+ }
+
+ if ($self->has_type_constraint) {
+
+ my $type_constraint = $self->type_constraint;
+
+ if ($self->should_coerce) {
+ $value = $type_constraint->coerce($value);
+ }
+ $type_constraint->_compiled_type_constraint->($value)
+ || confess "Attribute ("
+ . $self->name
+ . ") does not pass the type constraint because "
+ . $type_constraint->get_message($value);
+ }
+
+ my $meta_instance = Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance;
+
+ $meta_instance->set_slot_value($instance, $attr_name, $value);
+
+ if (ref $value && $self->is_weak_ref) {
+ $meta_instance->weaken_slot_value($instance, $attr_name);
+ }
+
+ if ($self->has_trigger) {
+ $self->trigger->($instance, $value, $self);
+ }
+}
+
+sub get_value {
+ my ($self, $instance) = @_;
+
+ if ($self->is_lazy) {
+ unless ($self->has_value($instance)) {
+ if ($self->has_default) {
+ my $default = $self->default($instance);
+ $self->set_initial_value($instance, $default);
+ }
+ if ( $self->has_builder ){
+ if (my $builder = $instance->can($self->builder)){
+ $self->set_initial_value($instance, $instance->$builder);
+ }
+ else {
+ confess(blessed($instance)
+ . " does not support builder method '"
+ . $self->builder
+ . "' for attribute '"
+ . $self->name
+ . "'");
+ }
+ }
+ else {
+ $self->set_initial_value($instance, undef);
+ }
+ }
+ }
+
+ if ($self->should_auto_deref) {
+
+ my $type_constraint = $self->type_constraint;
+
+ if ($type_constraint->is_a_type_of('ArrayRef')) {
+ my $rv = $self->SUPER::get_value($instance);
+ return unless defined $rv;
+ return wantarray ? @{ $rv } : $rv;
+ }
+ elsif ($type_constraint->is_a_type_of('HashRef')) {
+ my $rv = $self->SUPER::get_value($instance);
+ return unless defined $rv;
+ return wantarray ? %{ $rv } : $rv;
+ }
+ else {
+ confess "Can not auto de-reference the type constraint '" . $type_constraint->name . "'";
+ }
+
+ }
+ else {
+
+ return $self->SUPER::get_value($instance);
+ }
+}
+
+## installing accessors
+
+sub accessor_metaclass { 'Moose::Meta::Method::Accessor' }
+
+sub install_accessors {
+ my $self = shift;
+ $self->SUPER::install_accessors(@_);
+
+ if ($self->has_handles) {
+
+ # NOTE:
+ # Here we canonicalize the 'handles' option
+ # this will sort out any details and always
+ # return an hash of methods which we want
+ # to delagate to, see that method for details
+ my %handles = $self->_canonicalize_handles();
+
+ # find the accessor method for this attribute
+ my $accessor = $self->get_read_method_ref;
+ # then unpack it if we need too ...
+ $accessor = $accessor->body if blessed $accessor;
+
+ # install the delegation ...
+ my $associated_class = $self->associated_class;
+ foreach my $handle (keys %handles) {
+ my $method_to_call = $handles{$handle};
+ my $class_name = $associated_class->name;
+ my $name = "${class_name}::${handle}";
+
+ (!$associated_class->has_method($handle))
+ || confess "You cannot overwrite a locally defined method ($handle) with a delegation";
+
+ # NOTE:
+ # handles is not allowed to delegate
+ # any of these methods, as they will
+ # override the ones in your class, which
+ # is almost certainly not what you want.
+
+ # FIXME warn when $handle was explicitly specified, but not if the source is a regex or something
+ #cluck("Not delegating method '$handle' because it is a core method") and
+ next if $class_name->isa("Moose::Object") and $handle =~ /^BUILD|DEMOLISH$/ || Moose::Object->can($handle);
+
+ if ((reftype($method_to_call) || '') eq 'CODE') {
+ $associated_class->add_method($handle => subname $name, $method_to_call);
+ }
+ else {
+ # NOTE:
+ # we used to do a goto here, but the
+ # goto didn't handle failure correctly
+ # (it just returned nothing), so I took
+ # that out. However, the more I thought
+ # about it, the less I liked it doing
+ # the goto, and I prefered the act of
+ # delegation being actually represented
+ # in the stack trace.
+ # - SL
+ $associated_class->add_method($handle => subname $name, sub {
+ my $proxy = (shift)->$accessor();
+ (defined $proxy)
+ || confess "Cannot delegate $handle to $method_to_call because " .
+ "the value of " . $self->name . " is not defined";
+ $proxy->$method_to_call(@_);
+ });
+ }
+ }
+ }
+
+ return;
+}
+
+# private methods to help delegation ...
+
+sub _canonicalize_handles {
+ my $self = shift;
+ my $handles = $self->handles;
+ if (my $handle_type = ref($handles)) {
+ if ($handle_type eq 'HASH') {
+ return %{$handles};
+ }
+ elsif ($handle_type eq 'ARRAY') {
+ return map { $_ => $_ } @{$handles};
+ }
+ elsif ($handle_type eq 'Regexp') {
+ ($self->has_type_constraint)
+ || confess "Cannot delegate methods based on a RegExpr without a type constraint (isa)";
+ return map { ($_ => $_) }
+ grep { /$handles/ } $self->_get_delegate_method_list;
+ }
+ elsif ($handle_type eq 'CODE') {
+ return $handles->($self, $self->_find_delegate_metaclass);
+ }
+ else {
+ confess "Unable to canonicalize the 'handles' option with $handles";
+ }
+ }
+ else {
+ my $role_meta = eval { $handles->meta };
+ if ($@) {
+ confess "Unable to canonicalize the 'handles' option with $handles because : $@";
+ }
+
+ (blessed $role_meta && $role_meta->isa('Moose::Meta::Role'))
+ || confess "Unable to canonicalize the 'handles' option with $handles because ->meta is not a Moose::Meta::Role";
+
+ return map { $_ => $_ } (
+ $role_meta->get_method_list,
+ $role_meta->get_required_method_list
+ );
+ }
+}
+
+sub _find_delegate_metaclass {
+ my $self = shift;
+ if (my $class = $self->_isa_metadata) {
+ # if the class does have
+ # a meta method, use it
+ return $class->meta if $class->can('meta');
+ # otherwise we might be
+ # dealing with a non-Moose
+ # class, and need to make
+ # our own metaclass
+ return Moose::Meta::Class->initialize($class);
+ }
+ elsif (my $role = $self->_does_metadata) {
+ # our role will always have
+ # a meta method
+ return $role->meta;
+ }
+ else {
+ confess "Cannot find delegate metaclass for attribute " . $self->name;
+ }
+}
+
+sub _get_delegate_method_list {
+ my $self = shift;
+ my $meta = $self->_find_delegate_metaclass;
+ if ($meta->isa('Class::MOP::Class')) {
+ return map { $_->{name} } # NOTE: !never! delegate &meta
+ grep { $_->{class} ne 'Moose::Object' && $_->{name} ne 'meta' }
+ $meta->compute_all_applicable_methods;
+ }
+ elsif ($meta->isa('Moose::Meta::Role')) {
+ return $meta->get_method_list;
+ }
+ else {
+ confess "Unable to recognize the delegate metaclass '$meta'";
+ }
}
1;
=head1 DESCRIPTION
-This is a subclass of L<Class::MOP::Attribute> with Moose specific
-extensions.
+This is a subclass of L<Class::MOP::Attribute> with Moose specific
+extensions.
-For the most part, the only time you will ever encounter an
-instance of this class is if you are doing some serious deep
-introspection. To really understand this class, you need to refer
+For the most part, the only time you will ever encounter an
+instance of this class is if you are doing some serious deep
+introspection. To really understand this class, you need to refer
to the L<Class::MOP::Attribute> documentation.
=head1 METHODS
=head2 Overridden methods
-These methods override methods in L<Class::MOP::Attribute> and add
-Moose specific features. You can safely assume though that they
+These methods override methods in L<Class::MOP::Attribute> and add
+Moose specific features. You can safely assume though that they
will behave just as L<Class::MOP::Attribute> does.
=over 4
=item B<new>
-=item B<generate_accessor_method>
+=item B<initialize_instance_slot>
+
+=item B<install_accessors>
+
+=item B<accessor_metaclass>
+
+=item B<get_value>
-=item B<generate_writer_method>
+=item B<set_value>
-=item B<generate_reader_method>
+ eval { $point->meta->get_attribute('x')->set_value($point, 'fourty-two') };
+ if($@) {
+ print "Oops: $@\n";
+ }
+
+I<Attribute (x) does not pass the type constraint (Int) with 'fourty-two'>
+
+Before setting the value, a check is made on the type constraint of
+the attribute, if it has one, to see if the value passes it. If the
+value fails to pass, the set operation dies with a L<Carp/confess>.
+
+Any coercion to convert values is done before checking the type constraint.
+
+To check a value against a type constraint before setting it, fetch the
+attribute instance using L<Class::MOP::Class/find_attribute_by_name>,
+fetch the type_constraint from the attribute using L<Moose::Meta::Attribute/type_constraint>
+and call L<Moose::Meta::TypeConstraint/check>. See L<Moose::Cookbook::RecipeX>
+for an example.
=back
=head2 Additional Moose features
-Moose attributes support type-contstraint checking, weak reference
-creation and type coercion.
+Moose attributes support type-constraint checking, weak reference
+creation and type coercion.
=over 4
+=item B<clone_and_inherit_options>
+
+This is to support the C<has '+foo'> feature, it clones an attribute
+from a superclass and allows a very specific set of changes to be made
+to the attribute.
+
=item B<has_type_constraint>
Returns true if this meta-attribute has a type constraint.
=item B<type_constraint>
-A read-only accessor for this meta-attribute's type constraint. For
-more information on what you can do with this, see the documentation
+A read-only accessor for this meta-attribute's type constraint. For
+more information on what you can do with this, see the documentation
for L<Moose::Meta::TypeConstraint>.
+=item B<has_handles>
+
+Returns true if this meta-attribute performs delegation.
+
+=item B<handles>
+
+This returns the value which was passed into the handles option.
+
=item B<is_weak_ref>
-Returns true of this meta-attribute produces a weak reference.
+Returns true if this meta-attribute produces a weak reference.
+
+=item B<is_required>
+
+Returns true if this meta-attribute is required to have a value.
+
+=item B<is_lazy>
+
+Returns true if this meta-attribute should be initialized lazily.
+
+NOTE: lazy attributes, B<must> have a C<default> or C<builder> field set.
+
+=item B<is_lazy_build>
+
+Returns true if this meta-attribute should be initialized lazily through
+the builder generated by lazy_build. Using C<lazy_build =E<gt> 1> will
+make your attribute required and lazy. In addition it will set the builder, clearer
+and predicate options for you using the following convention.
+
+ #If your attribute name starts with an underscore:
+ has '_foo' => (lazy_build => 1);
+ #is the same as
+ has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', builder => '_build__foo);
+ # or
+ has '_foo' => (lazy => 1, required => 1, predicate => '_has_foo', clearer => '_clear_foo', default => sub{shift->_build__foo});
+
+ #If your attribute name does not start with an underscore:
+ has 'foo' => (lazy_build => 1);
+ #is the same as
+ has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', builder => '_build_foo);
+ # or
+ has 'foo' => (lazy => 1, required => 1, predicate => 'has_foo', clearer => 'clear_foo', default => sub{shift->_build_foo});
+
+The reason for the different naming of the C<builder> is that the C<builder>
+method is a private method while the C<clearer> and C<predicate> methods
+are public methods.
+
+NOTE: This means your class should provide a method whose name matches the value
+of the builder part, in this case _build__foo or _build_foo.
=item B<should_coerce>
-Returns true of this meta-attribute should perform type coercion.
+Returns true if this meta-attribute should perform type coercion.
+
+=item B<should_auto_deref>
+
+Returns true if this meta-attribute should perform automatic
+auto-dereferencing.
+
+NOTE: This can only be done for attributes whose type constraint is
+either I<ArrayRef> or I<HashRef>.
+
+=item B<has_trigger>
+
+Returns true if this meta-attribute has a trigger set.
+
+=item B<trigger>
+
+This is a CODE reference which will be executed every time the
+value of an attribute is assigned. The CODE ref will get two values,
+the invocant and the new value. This can be used to handle I<basic>
+bi-directional relations.
+
+=item B<documentation>
+
+This is a string which contains the documentation for this attribute.
+It serves no direct purpose right now, but it might in the future
+in some kind of automated documentation system perhaps.
+
+=item B<has_documentation>
+
+Returns true if this meta-attribute has any documentation.
=back
=head1 BUGS
-All complex software has bugs lurking in it, and this module is no
+All complex software has bugs lurking in it, and this module is no
exception. If you find a bug please either email me, or add the bug
to cpan-RT.
Stevan Little E<lt>stevan@iinteractive.comE<gt>
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
+
=head1 COPYRIGHT AND LICENSE
-Copyright 2006 by Infinity Interactive, Inc.
+Copyright 2006-2008 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
-it under the same terms as Perl itself.
+it under the same terms as Perl itself.
-=cut
\ No newline at end of file
+=cut
projects / gitmo/Moose.git / blobdiff