use strict;
use warnings;
-use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'weaken';
our $VERSION = '0.01';
}
sub new {
- my ( $class, $meta ) = @_;
+ my ($class, $meta, @attrs) = @_;
+ my @slots = map { $_->slots } @attrs;
bless {
- meta => $meta,
- instance_layout => {}
+ # 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 => \@slots,
} => $class;
}
sub create_instance {
- my ( $self, $class ) = @_;
-
- # rely on autovivification
- $self->bless_instance_structure( {}, $class );
+ my $self = shift;
+ $self->bless_instance_structure({});
}
sub bless_instance_structure {
- my ( $self, $instance_structure, $class ) = @_;
- $class ||= $self->{meta}->name;
- bless $instance_structure, $class;
-}
-
-sub get_all_parents {
- my $self = shift;
- my @parents = $self->{meta}->class_precedence_list;
- shift @parents; # shift off ourselves
- return map { $_->get_meta_instance } map { $_->meta || () } @parents;
+ my ($self, $instance_structure) = @_;
+ bless $instance_structure, $self->{meta}->name;
}
# operations on meta instance
-sub add_slot {
- my ($self, $slot_name ) = @_;
- confess "The slot '$slot_name' already exists"
- if 0 && $self->has_slot_recursively( $slot_name ); # FIXME
- $self->{instance_layout}->{$slot_name} = undef;
-}
-
sub get_all_slots {
my $self = shift;
- keys %{ $self->{instance_layout} };
-}
-
-sub get_all_slots_recursively {
- my $self = shift;
- return (
- $self->get_all_slots,
- map { $_->get_all_slots } $self->get_all_parents,
- ),
-}
-
-sub has_slot {
- my ($self, $slot_name) = @_;
- exists $self->{instance_layout}->{$slot_name} ? 1 : 0;
-}
-
-sub has_slot_recursively {
- my ( $self, $slot_name ) = @_;
- return 1 if $self->has_slot($slot_name);
- $_->has_slot_recursively($slot_name) && return 1 for $self->get_all_parents;
- return 0;
-}
-
-sub remove_slot {
- my ( $self, $slot_name ) = @_;
- # NOTE:
- # this does not search recursively cause
- # that is not the domain of this meta-instance
- # it is specific to this class ...
- confess "The slot '$slot_name' does not exist (maybe it's inherited?)"
- if 0 && $self->has_slot( $slot_name ); # FIXME
- delete $self->{instance_layout}->{$slot_name};
+ return @{$self->{slots}};
}
-
# operations on created instances
sub get_slot_value {
return $instance->{$slot_name};
}
-# can be called only after initialize_slot_value
sub set_slot_value {
my ($self, $instance, $slot_name, $value) = @_;
$instance->{$slot_name} = $value;
}
-# convenience method
-# non autovivifying stores will have this as { initialize_slot unless slot_initlized; set_slot_value }
-sub set_slot_value_with_init {
- my ( $self, $instance, $slot_name, $value ) = @_;
- $self->set_slot_value( $instance, $slot_name, $value );
-}
-
sub initialize_slot {
- my ( $self, $instance, $slot_name ) = @_;
-}
-
-sub slot_initialized {
my ($self, $instance, $slot_name) = @_;
- exists $instance->{$slot_name} ? 1 : 0;
+ $instance->{$slot_name} = undef;
}
-
-# inlinable operation snippets
-
-sub inline_get_slot_value {
- my ($self, $instance, $slot_name) = @_;
- sprintf "%s->{%s}", $instance, $slot_name;
+sub initialize_all_slots {
+ my ($self, $instance) = @_;
+ foreach my $slot_name ($self->get_all_slots) {
+ $self->initialize_slot($instance, $slot_name);
+ }
}
-sub inline_set_slot_value {
+sub is_slot_initialized {
my ($self, $instance, $slot_name, $value) = @_;
- $self->_inline_slot_lvalue . " = $value",
+ exists $instance->{$slot_name} ? 1 : 0;
}
-sub inline_set_slot_value_with_init {
- my ( $self, $instance, $slot_name, $value) = @_;
- $self->inline_set_slot_value( $instance, $slot_name, $value ) . ";";
+sub set_slot_value_weak {
+ my ($self, $instance, $slot_name, $value) = @_;
+ $self->set_slot_value($instance, $slot_name, $value);
+ $self->weaken_slot_value($instance, $slot_name);
}
-sub inline_initialize_slot {
- return "";
+sub weaken_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ weaken $instance->{$slot_name};
}
-sub inline_slot_initialized {
- my ($self, $instance, $slot_name) = @_;
- "exists " . $self->inline_get_slot_value;
-}
-
-sub _inline_slot_lvalue {
- my ($self, $instance, $slot_name) = @_;
- $self->inline_slot_value;
+sub strengthen_slot_value {
+ my ($self, $instance, $slot_name) = @_;
+ $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name));
}
1;
=head1 SYNOPSIS
+ # for the most part, this protocol is internal
+ # and not for public usage, but this how one
+ # might use it
+
+ package Foo;
+
+ use strict;
+ use warnings;
+ use metaclass 'Class::MOP::Class' => (
+ ':instance_metaclass' => 'ArrayBasedStorage::Instance',
+ );
+
+ # now Foo->new produces blessed ARRAY ref based objects
+
=head1 DESCRIPTION
+This is a sub-protocol which governs instance creation
+and access to the slots of the instance structure.
+
+This may seem like over-abstraction, but by abstracting
+this process into a sub-protocol we make it possible to
+easily switch the details of how an object's instance is
+stored with minimal impact. In most cases just subclassing
+this class will be all you need to do (occasionally it
+requires that you also subclass Class::MOP::Attribute if
+you require some kind of specific attribute initializations).
+
=head1 METHODS
=over 4
-=item B<new>
-
-=item B<add_slot>
+=item B<new ($meta, @attrs)>
-=item B<bless_instance_structure>
+Creates a new instance meta-object and gathers all the slots from
+the list of C<@attrs> given.
-=item B<create_instance>
+=item B<meta>
-=item B<get_all_parents>
+This will return a B<Class::MOP::Class> instance which is related
+to this class.
-=item B<get_slot_value>
+=back
-=item B<has_slot>
+=head2 Creation of Instances
-=item B<has_slot_recursively>
+=over 4
-=item B<initialize_slot>
+=item B<create_instance>
-=item B<inline_get_slot_value>
+This creates the appropriate structure needed for the instance and
+then calls C<bless_instance_structure> to bless it into the class.
-=item B<inline_initialize_slot>
+=item B<bless_instance_structure ($instance_structure)>
-=item B<inline_set_slot_value>
+This does just exactly what it says it does.
-=item B<inline_set_slot_value_with_init>
+=back
-=item B<inline_slot_initialized>
+=head2 Instrospection
-=item B<remove_slot>
+NOTE: There might be more methods added to this part of the API,
+we will add then when we need them basically.
-=item B<set_slot_value>
+=over 4
-=item B<set_slot_value_with_init>
+=item B<get_all_slots>
-=item B<slot_initialized>
+This will return the current list of slots based on what was
+given to this object in C<new>.
=back
-=head2 Introspection
+=head2 Operations on Instance Structures
+
+An important distinction of this sub-protocol is that the
+instance meta-object is a different entity from the actual
+instance it creates. For this reason, any actions on slots
+require that the C<$instance_structure> is passed into them.
=over 4
-=item B<meta>
+=item B<get_slot_value ($instance_structure, $slot_name)>
-This will return a B<Class::MOP::Class> instance which is related
-to this class.
+=item B<set_slot_value ($instance_structure, $slot_name, $value)>
+
+=item B<initialize_slot ($instance_structure, $slot_name)>
+
+=item B<initialize_all_slots ($instance_structure)>
+
+=item B<is_slot_initialized ($instance_structure, $slot_name)>
+
+=item B<set_slot_value_weak ($instance_structure, $slot_name, $ref_value)>
+
+=item B<weaken_slot_value>
+
+=item B<strengthen_slot_value>
=back
=head1 AUTHOR
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
+
Stevan Little E<lt>stevan@iinteractive.comE<gt>
=head1 COPYRIGHT AND LICENSE
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