-package # hide the package from PAUSE
- InsideOutClass;
-
-use strict;
-use warnings;
-
-our $VERSION = '0.03';
-
-use Scalar::Util 'refaddr';
-
-use base 'Class::MOP::Class';
-
-sub construct_instance {
- my ($class, %params) = @_;
- # create a scalar ref to use as
- # the inside-out instance
- my $instance = \(my $var);
- foreach my $attr ($class->compute_all_applicable_attributes()) {
- # if the attr has an init_arg, use that, otherwise,
- # use the attributes name itself as the init_arg
- my $init_arg = $attr->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)
- $val ||= $attr->default($instance) if $attr->has_default();
- # now add this to the instance structure
- $class->get_package_variable('%' . $attr->name)->{ refaddr($instance) } = $val;
- }
- return $instance;
-}
package # hide the package from PAUSE
- InsideOutClass::Attribute;
+ InsideOutClass::Instance;
use strict;
use warnings;
-our $VERSION = '0.04';
+our $VERSION = '0.06';
+use Carp 'confess';
use Scalar::Util 'refaddr';
-use base 'Class::MOP::Attribute';
+use base 'Class::MOP::Instance';
+
+sub create_instance {
+ my ( $self, $class ) = @_;
+ my $x;
+ bless \$x, $class || $self->{meta}->name;
+}
-sub generate_accessor_method {
- my ($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]) };
- }';
+sub add_slot {
+ my ( $self, $slot_name ) = @_;
+ $self->{containers}{$slot_name} = do {
+ my $fqn = $self->{meta}->name . "::" . $slot_name;
+ no strict 'refs';
+ \%$fqn;
+ };
+ $self->SUPER::add_slot( $slot_name );
}
-sub generate_reader_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
- $' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) };
- }';
+sub get_slot_value {
+ my ( $self, $instance, $slot_name ) = @_;
+ confess "$self is no instance" unless ref $self;
+ $self->{containers}{$slot_name}{refaddr $instance};
}
-sub generate_writer_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
- $' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) } = $_[1];
- }';
+sub set_slot_value {
+ my ( $self, $instance, $slot_name, $value ) = @_;
+ $self->{containers}{$slot_name}{refaddr $instance} = $value;
}
-sub generate_predicate_method {
- my ($self, $attr_name) = @_;
- eval 'sub {
- defined($' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) }) ? 1 : 0;
- }';
+sub initialize_slot { }
+
+sub slot_initialized {
+ my ( $self, $instance, $slot_name ) = @_;
+ exists $self->{containers}{$slot_name}{refaddr $instance};
}
-## &remove_attribute is left as an exercise for the reader :)
+## &remove_slot is left as an exercise for the reader :)
1;
package Foo;
- use metaclass 'InsideOutClass' => (
+ use metaclass 'Class::MOP::Class' => (
# tell our metaclass to use the
# InsideOut attribute metclass
# to construct all it's attributes
- ':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.
-First step is to subclass B<Class::MOP::Class> and override the
-C<construct_instance> method. The default C<construct_instance>
-will create a HASH reference using the parameters and attribute
-default values. Since inside-out objects don't use HASH refs, and
-use package variables instead, we need to write code to handle
-this difference.
-
-The next step is to create the subclass of B<Class::MOP::Attribute>
-and override the method generation code. This requires overloading
-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
Stevan Little E<lt>stevan@iinteractive.comE<gt>
+=head1 SEE ALSO
+
+L<Tie::RefHash::Weak>
+
=head1 COPYRIGHT AND LICENSE
Copyright 2006 by Infinity Interactive, Inc.
projects / gitmo/Class-MOP.git / blobdiff