-
package # hide the package from PAUSE
InsideOutClass::Attribute;
use strict;
use warnings;
-our $VERSION = '0.06';
+our $VERSION = '0.02';
use Carp 'confess';
use Scalar::Util 'refaddr';
use base 'Class::MOP::Attribute';
sub initialize_instance_slot {
- my ($self, $class, $meta_instance, $params) = @_;
- # if the attr has an init_arg, use that, otherwise,
- # use the attributes name itself as the init_arg
- my $init_arg = $self->init_arg();
+ my ($self, $meta_instance, $instance, $params) = @_;
+ my $init_arg = $self->{init_arg};
# try to fetch the init arg from the %params ...
my $val;
$val = $params->{$init_arg} if exists $params->{$init_arg};
# if nothing was in the %params, we can use the
# attribute's default value (if it has one)
- if (!defined $val && $self->has_default) {
- $val = $self->default($meta_instance->get_instance);
+ if (!defined $val && defined $self->{default}) {
+ $val = $self->default($instance);
}
- # now add this to the instance structure
- $class->get_package_variable('%' . $self->name)->{ refaddr($meta_instance->get_instance) } = $val;
+ my $_meta_instance = $self->associated_class->get_meta_instance;
+ $_meta_instance->initialize_slot($instance, $self->name);
+ $_meta_instance->set_slot_value($instance, $self->name, $val);
}
+sub accessor_metaclass { 'InsideOutClass::Method::Accessor' }
+
+package # hide the package from PAUSE
+ InsideOutClass::Method::Accessor;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.01';
+
+use Carp 'confess';
+use Scalar::Util 'refaddr';
+
+use base 'Class::MOP::Method::Accessor';
+
+## Method generation helpers
+
sub generate_accessor_method {
- my ($self, $attr_name) = @_;
- $attr_name = ($self->associated_class->name . '::' . $attr_name);
- eval 'sub {
- $' . $attr_name . '{ refaddr($_[0]) } = $_[1] if scalar(@_) == 2;
- $' . $attr_name . '{ refaddr($_[0]) };
- }';
+ my $attr = (shift)->associated_attribute;
+ my $meta_class = $attr->associated_class;
+ my $attr_name = $attr->name;
+ return sub {
+ my $meta_instance = $meta_class->get_meta_instance;
+ $meta_instance->set_slot_value($_[0], $attr_name, $_[1]) if scalar(@_) == 2;
+ $meta_instance->get_slot_value($_[0], $attr_name);
+ };
}
sub generate_reader_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
+ my $attr = (shift)->associated_attribute;
+ my $meta_class = $attr->associated_class;
+ my $attr_name = $attr->name;
+ return sub {
confess "Cannot assign a value to a read-only accessor" if @_ > 1;
- $' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) };
- }';
+ $meta_class->get_meta_instance
+ ->get_slot_value($_[0], $attr_name);
+ };
}
sub generate_writer_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
- $' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) } = $_[1];
- }';
+ my $attr = (shift)->associated_attribute;
+ my $meta_class = $attr->associated_class;
+ my $attr_name = $attr->name;
+ return sub {
+ $meta_class->get_meta_instance
+ ->set_slot_value($_[0], $attr_name, $_[1]);
+ };
}
sub generate_predicate_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
- defined($' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) }) ? 1 : 0;
- }';
+ my $attr = (shift)->associated_attribute;
+ my $meta_class = $attr->associated_class;
+ my $attr_name = $attr->name;
+ return sub {
+ defined $meta_class->get_meta_instance
+ ->get_slot_value($_[0], $attr_name) ? 1 : 0;
+ };
+}
+
+package # hide the package from PAUSE
+ InsideOutClass::Instance;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.01';
+
+use Carp 'confess';
+use Scalar::Util 'refaddr';
+
+use base 'Class::MOP::Instance';
+
+sub create_instance {
+ my ($self, $class) = @_;
+ $self->bless_instance_structure(\(my $instance));
}
-## &remove_attribute is left as an exercise for the reader :)
+sub get_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->{meta}->get_package_symbol('%' . $slot_name)->{refaddr $instance};
+}
+
+sub set_slot_value {
+ my ($self, $instance, $slot_name, $value) = @_;
+ $self->{meta}->get_package_symbol('%' . $slot_name)->{refaddr $instance} = $value;
+}
+
+sub initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ $self->{meta}->add_package_symbol(('%' . $slot_name) => {})
+ unless $self->{meta}->has_package_symbol('%' . $slot_name);
+ $self->{meta}->get_package_symbol('%' . $slot_name)->{refaddr $instance} = undef;
+}
+
+sub is_slot_initialized {
+ my ($self, $instance, $slot_name) = @_;
+ return 0 unless $self->{meta}->has_package_symbol('%' . $slot_name);
+ return exists $self->{meta}->get_package_symbol('%' . $slot_name)->{refaddr $instance} ? 1 : 0;
+}
1;
package Foo;
- use metaclass 'Class::MOP::Class' => (
- # tell our metaclass to use the
- # InsideOut attribute metclass
- # to construct all it's attributes
- ':attribute_metaclass' => 'InsideOutClass::Attribute'
+ use metaclass (
+ ':attribute_metaclass' => 'InsideOutClass::Attribute',
+ ':instance_metaclass' => 'InsideOutClass::Instance'
);
__PACKAGE__->meta->add_attribute('foo' => (
class technique. What follows is a brief explaination of the code
found in this module.
-We must create a subclass of B<Class::MOP::Attribute> and override
-the instance initialization and method generation code. This requires
-overloading C<initialize_instance_slot>, C<generate_accessor_method>,
-C<generate_reader_method>, C<generate_writer_method> and
-C<generate_predicate_method>. All other aspects are taken care of with
-the existing B<Class::MOP::Attribute> infastructure.
+We must create a subclass of B<Class::MOP::Instance> and override
+the slot operations. This requires
+overloading C<get_slot_value>, C<set_slot_value>, C<slot_initialized>, and
+C<initialize_slot>, as well as their inline counterparts. Additionally we
+overload C<add_slot> in order to initialize the global hash containing the
+actual slot values.
And that is pretty much all. Of course I am ignoring need for
inside-out objects to be C<DESTROY>-ed, and some other details as
-well, but this is an example. A real implementation is left as an
-exercise to the reader.
+well (threading, etc), but this is an example. A real implementation is left as
+an exercise to the reader.
-=head1 AUTHOR
+=head1 AUTHORS
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.