package # hide the package from PAUSE
- InsideOutClass;
+ InsideOutClass::Attribute;
use strict;
use warnings;
-our $VERSION = '0.03';
+our $VERSION = '0.02';
+use Carp 'confess';
use Scalar::Util 'refaddr';
-use base 'Class::MOP::Class';
-
-sub construct_instance {
- my ($class, %params) = @_;
- # create a scalar ref to use as
- # the inside-out instance
- my $instance = \(my $var);
- foreach my $attr (map { $_->{attribute} } $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->has_init_arg() ? $attr->init_arg() : $attr->name;
- # 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 $instance;
+use base 'Class::MOP::Attribute';
+
+sub initialize_instance_slot {
+ my ($self, $meta_instance, $instance, $params) = @_;
+ my $init_arg = $self->init_arg;
+ # try to fetch the init arg from the %params ...
+ my $val;
+ $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 && defined $self->default) {
+ $val = $self->default($instance);
+ }
+ 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);
}
-package # hide the package from PAUSE
- InsideOutClass::Attribute;
+sub accessor_metaclass { 'InsideOutClass::Method::Accessor' }
+package # hide the package from PAUSE
+ InsideOutClass::Method::Accessor;
+
use strict;
use warnings;
-our $VERSION = '0.04';
+our $VERSION = '0.01';
+use Carp 'confess';
use Scalar::Util 'refaddr';
-use base 'Class::MOP::Attribute';
+use base 'Class::MOP::Method::Accessor';
+
+## Method generation helpers
sub generate_accessor_method {
- my ($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 {
- $' . ($self->associated_class->name . '::' . $attr_name) . '{ refaddr($_[0]) };
- }';
+ 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;
+ $meta_class->get_meta_instance
+ ->get_slot_value($_[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 $instance));
+}
+
+sub get_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance};
}
-## &remove_attribute is left as an exercise for the reader :)
+sub set_slot_value {
+ my ($self, $instance, $slot_name, $value) = @_;
+ $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} = $value;
+}
+
+sub initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ $self->associated_metaclass->add_package_symbol(('%' . $slot_name) => {})
+ unless $self->associated_metaclass->has_package_symbol('%' . $slot_name);
+ $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} = undef;
+}
+
+sub is_slot_initialized {
+ my ($self, $instance, $slot_name) = @_;
+ return 0 unless $self->associated_metaclass->has_package_symbol('%' . $slot_name);
+ return exists $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} ? 1 : 0;
+}
1;
package Foo;
- sub meta {
- InsideOutClass->initialize($_[0] => (
- # 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' => (
reader => 'get_foo',
sub new {
my $class = shift;
- bless $class->meta->construct_instance(@_) => $class;
- }
+ $class->meta->new_object(@_);
+ }
# now you can just use the class as normal
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
+=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.
projects / gitmo/Class-MOP.git / blobdiff