use strict;
use warnings;
-use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'weaken', 'blessed';
-our $VERSION = '0.01';
+our $VERSION = '0.03';
+our $AUTHORITY = 'cpan:STEVAN';
sub meta {
require Class::MOP::Class;
}
sub new {
- my $class = shift;
- my $meta = shift;
- bless {
- instance => bless {} => $meta->name
+ my ($class, $meta, @attrs) = @_;
+ my @slots = map { $_->slots } @attrs;
+ my $instance = bless {
+ # NOTE:
+ # I am not sure that it makes
+ # sense to pass in the meta
+ # The ideal would be to just
+ # pass in the class name, but
+ # that is placing too much of
+ # an assumption on bless(),
+ # which is *probably* a safe
+ # assumption,.. but you can
+ # never tell <:)
+ '$!meta' => $meta,
+ '@!slots' => { map { $_ => undef } @slots },
} => $class;
+
+ weaken($instance->{'$!meta'});
+
+ return $instance;
}
-sub add_slot {
- my ($self, $slot_name, $value) = @_;
- return $self->{instance}->{$slot_name} = $value;
+sub associated_metaclass { (shift)->{'$!meta'} }
+
+sub create_instance {
+ my $self = shift;
+ $self->bless_instance_structure({});
+}
+
+sub bless_instance_structure {
+ my ($self, $instance_structure) = @_;
+ bless $instance_structure, $self->associated_metaclass->name;
+}
+
+sub clone_instance {
+ my ($self, $instance) = @_;
+ $self->bless_instance_structure({ %$instance });
+}
+
+# operations on meta instance
+
+sub get_all_slots {
+ my $self = shift;
+ return keys %{$self->{'@!slots'}};
+}
+
+sub is_valid_slot {
+ my ($self, $slot_name) = @_;
+ exists $self->{'@!slots'}->{$slot_name} ? 1 : 0;
}
-sub get_instance { (shift)->{instance} }
+# operations on created instances
+
+sub get_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ return $instance->{$slot_name};
+}
+
+sub set_slot_value {
+ my ($self, $instance, $slot_name, $value) = @_;
+ $instance->{$slot_name} = $value;
+}
+
+sub initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ $self->set_slot_value($instance, $slot_name, undef);
+}
+
+sub deinitialize_slot {
+ my ( $self, $instance, $slot_name ) = @_;
+ delete $instance->{$slot_name};
+}
+
+sub initialize_all_slots {
+ my ($self, $instance) = @_;
+ foreach my $slot_name ($self->get_all_slots) {
+ $self->initialize_slot($instance, $slot_name);
+ }
+}
+
+sub deinitialize_all_slots {
+ my ($self, $instance) = @_;
+ foreach my $slot_name ($self->get_all_slots) {
+ $self->deinitialize_slot($instance, $slot_name);
+ }
+}
+
+sub is_slot_initialized {
+ my ($self, $instance, $slot_name, $value) = @_;
+ exists $instance->{$slot_name} ? 1 : 0;
+}
+
+sub weaken_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ weaken $instance->{$slot_name};
+}
+
+sub strengthen_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name));
+}
+
+# inlinable operation snippets
+
+sub is_inlinable { 1 }
+
+sub inline_create_instance {
+ my ($self, $class_variable) = @_;
+ 'bless {} => ' . $class_variable;
+}
+
+sub inline_slot_access {
+ my ($self, $instance, $slot_name) = @_;
+ sprintf "%s->{%s}", $instance, $slot_name;
+}
+
+sub inline_get_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->inline_slot_access($instance, $slot_name);
+}
+
+sub inline_set_slot_value {
+ my ($self, $instance, $slot_name, $value) = @_;
+ $self->inline_slot_access($instance, $slot_name) . " = $value",
+}
+
+sub inline_initialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ $self->inline_set_slot_value($instance, $slot_name, 'undef'),
+}
+
+sub inline_deinitialize_slot {
+ my ($self, $instance, $slot_name) = @_;
+ "delete " . $self->inline_slot_access($instance, $slot_name);
+}
+sub inline_is_slot_initialized {
+ my ($self, $instance, $slot_name) = @_;
+ "exists " . $self->inline_slot_access($instance, $slot_name) . " ? 1 : 0";
+}
+
+sub inline_weaken_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ sprintf "Scalar::Util::weaken( %s )", $self->inline_slot_access($instance, $slot_name);
+}
+
+sub inline_strengthen_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->inline_set_slot_value($instance, $slot_name, $self->inline_slot_access($instance, $slot_name));
+}
1;
=head1 SYNOPSIS
+ # for the most part, this protocol is internal
+ # and not for public usage, but this how one
+ # might use it
+
+ package Foo;
+
+ use strict;
+ use warnings;
+ use metaclass (
+ ':instance_metaclass' => 'ArrayBasedStorage::Instance',
+ );
+
+ # now Foo->new produces blessed ARRAY ref based objects
+
=head1 DESCRIPTION
+This is a sub-protocol which governs instance creation
+and access to the slots of the instance structure.
+
+This may seem like over-abstraction, but by abstracting
+this process into a sub-protocol we make it possible to
+easily switch the details of how an object's instance is
+stored with minimal impact. In most cases just subclassing
+this class will be all you need to do (see the examples;
+F<examples/ArrayBasedStorage.pod> and
+F<examples/InsideOutClass.pod> for details).
+
=head1 METHODS
=over 4
-=item B<new>
+=item B<new ($meta, @attrs)>
-=item B<add_slot>
+Creates a new instance meta-object and gathers all the slots from
+the list of C<@attrs> given.
-=item B<get_instance>
+=item B<meta>
+
+This will return a B<Class::MOP::Class> instance which is related
+to this class.
=back
-=head2 Introspection
+=head2 Creation of Instances
=over 4
-=item B<meta>
+=item B<create_instance>
-This will return a B<Class::MOP::Class> instance which is related
-to this class.
+This creates the appropriate structure needed for the instance and
+then calls C<bless_instance_structure> to bless it into the class.
+
+=item B<bless_instance_structure ($instance_structure)>
+
+This does just exactly what it says it does.
+
+=item B<clone_instance ($instance_structure)>
+
+=back
+
+=head2 Instrospection
+
+NOTE: There might be more methods added to this part of the API,
+we will add then when we need them basically.
+
+=over 4
+
+=item B<associated_metaclass>
+
+=item B<get_all_slots>
+
+This will return the current list of slots based on what was
+given to this object in C<new>.
+
+=item B<is_valid_slot ($slot_name)>
+
+=back
+
+=head2 Operations on Instance Structures
+
+An important distinction of this sub-protocol is that the
+instance meta-object is a different entity from the actual
+instance it creates. For this reason, any actions on slots
+require that the C<$instance_structure> is passed into them.
+
+=over 4
+
+=item B<get_slot_value ($instance_structure, $slot_name)>
+
+=item B<set_slot_value ($instance_structure, $slot_name, $value)>
+
+=item B<initialize_slot ($instance_structure, $slot_name)>
+
+=item B<deinitialize_slot ($instance_structure, $slot_name)>
+
+=item B<initialize_all_slots ($instance_structure)>
+
+=item B<deinitialize_all_slots ($instance_structure)>
+
+=item B<is_slot_initialized ($instance_structure, $slot_name)>
+
+=item B<weaken_slot_value ($instance_structure, $slot_name)>
+
+=item B<strengthen_slot_value ($instance_structure, $slot_name)>
+
+=back
+
+=head2 Inlineable Instance Operations
+
+This part of the API is currently un-used. It is there for use
+in future experiments in class finailization mostly. Best to
+ignore this for now.
+
+=over 4
+
+=item B<is_inlinable>
+
+Each meta-instance should override this method to tell Class::MOP if it's
+possible to inline the slot access.
+
+This is currently only used by Class::MOP::Class::Immutable when performing
+optimizations.
+
+=item B<inline_create_instance>
+
+=item B<inline_slot_access ($instance_structure, $slot_name)>
+
+=item B<inline_get_slot_value ($instance_structure, $slot_name)>
+
+=item B<inline_set_slot_value ($instance_structure, $slot_name, $value)>
+
+=item B<inline_initialize_slot ($instance_structure, $slot_name)>
+
+=item B<inline_deinitialize_slot ($instance_structure, $slot_name)>
+
+=item B<inline_is_slot_initialized ($instance_structure, $slot_name)>
+
+=item B<inline_weaken_slot_value ($instance_structure, $slot_name)>
+
+=item B<inline_strengthen_slot_value ($instance_structure, $slot_name)>
=back
-=head1 AUTHOR
+=head1 AUTHORS
+
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
Stevan Little E<lt>stevan@iinteractive.comE<gt>
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
-=cut
\ No newline at end of file
+=cut
+
projects / gitmo/Class-MOP.git / blobdiff