use strict;
use warnings;
+use Class::MOP::Method::Accessor;
+
use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype';
+use Scalar::Util 'blessed', 'reftype', 'weaken';
+
+our $VERSION = '0.14';
+our $AUTHORITY = 'cpan:STEVAN';
-our $VERSION = '0.01';
+use base 'Class::MOP::Object';
sub meta {
require Class::MOP::Class;
- Class::MOP::Class->initialize($_[0])
+ Class::MOP::Class->initialize(blessed($_[0]) || $_[0]);
}
# NOTE: (meta-circularity)
-# This method will be replaces in the
+# This method will be replaced in the
# boostrap section of Class::MOP, by
# a new version which uses the
# &Class::MOP::Class::construct_instance
(defined $name && $name)
|| confess "You must provide a name for the attribute";
- (!exists $options{reader} && !exists $options{writer})
- || confess "You cannot declare an accessor and reader and/or writer functions"
- if exists $options{accessor};
+
+ $options{init_arg} = $name
+ if not exists $options{init_arg};
+
+ (is_default_a_coderef(\%options))
+ || confess("References are not allowed as default values, you must ".
+ "wrap then in a CODE reference (ex: sub { [] } and not [])")
+ if exists $options{default} && ref $options{default};
bless {
- name => $name,
- accessor => $options{accessor},
- reader => $options{reader},
- writer => $options{writer},
- predicate => $options{predicate},
- init_arg => $options{init_arg},
- default => $options{default}
+ '$!name' => $name,
+ '$!accessor' => $options{accessor},
+ '$!reader' => $options{reader},
+ '$!writer' => $options{writer},
+ '$!predicate' => $options{predicate},
+ '$!clearer' => $options{clearer},
+ '$!init_arg' => $options{init_arg},
+ '$!default' => $options{default},
+ # keep a weakened link to the
+ # class we are associated with
+ '$!associated_class' => undef,
+ # and a list of the methods
+ # associated with this attr
+ '@!associated_methods' => [],
} => $class;
}
-sub name { $_[0]->{name} }
+# NOTE:
+# this is a primative (and kludgy) clone operation
+# for now, it will be replaced in the Class::MOP
+# bootstrap with a proper one, however we know
+# that this one will work fine for now.
+sub clone {
+ my $self = shift;
+ my %options = @_;
+ (blessed($self))
+ || confess "Can only clone an instance";
+ return bless { %{$self}, %options } => blessed($self);
+}
+
+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);
+ }
+ $meta_instance->set_slot_value($instance, $self->name, $val);
+}
+
+# NOTE:
+# the next bunch of methods will get bootstrapped
+# away in the Class::MOP bootstrapping section
+
+sub name { $_[0]->{'$!name'} }
+
+sub associated_class { $_[0]->{'$!associated_class'} }
+sub associated_methods { $_[0]->{'@!associated_methods'} }
-sub has_accessor { defined($_[0]->{accessor}) ? 1 : 0 }
-sub has_reader { defined($_[0]->{reader}) ? 1 : 0 }
-sub has_writer { defined($_[0]->{writer}) ? 1 : 0 }
-sub has_predicate { defined($_[0]->{predicate}) ? 1 : 0 }
-sub has_init_arg { defined($_[0]->{init_arg}) ? 1 : 0 }
-sub has_default { defined($_[0]->{default}) ? 1 : 0 }
+sub has_accessor { defined($_[0]->{'$!accessor'}) ? 1 : 0 }
+sub has_reader { defined($_[0]->{'$!reader'}) ? 1 : 0 }
+sub has_writer { defined($_[0]->{'$!writer'}) ? 1 : 0 }
+sub has_predicate { defined($_[0]->{'$!predicate'}) ? 1 : 0 }
+sub has_clearer { defined($_[0]->{'$!clearer'}) ? 1 : 0 }
+sub has_init_arg { defined($_[0]->{'$!init_arg'}) ? 1 : 0 }
+sub has_default { defined($_[0]->{'$!default'}) ? 1 : 0 }
-sub accessor { $_[0]->{accessor} }
-sub reader { $_[0]->{reader} }
-sub writer { $_[0]->{writer} }
-sub predicate { $_[0]->{predicate} }
-sub init_arg { $_[0]->{init_arg} }
+sub accessor { $_[0]->{'$!accessor'} }
+sub reader { $_[0]->{'$!reader'} }
+sub writer { $_[0]->{'$!writer'} }
+sub predicate { $_[0]->{'$!predicate'} }
+sub clearer { $_[0]->{'$!clearer'} }
+sub init_arg { $_[0]->{'$!init_arg'} }
+
+# end bootstrapped away method section.
+# (all methods below here are kept intact)
+
+sub is_default_a_coderef {
+ ('CODE' eq (reftype($_[0]->{'$!default'} || $_[0]->{default}) || ''))
+}
sub default {
- my $self = shift;
- if (reftype($self->{default}) && reftype($self->{default}) eq 'CODE') {
+ my ($self, $instance) = @_;
+ if (defined $instance && $self->is_default_a_coderef) {
# if the default is a CODE ref, then
# we pass in the instance and default
# can return a value based on that
# instance. Somewhat crude, but works.
- return $self->{default}->(shift);
+ return $self->{'$!default'}->($instance);
}
- $self->{default};
+ $self->{'$!default'};
}
-{
- # this is just a utility routine to
- # handle the details of accessors
- my $_inspect_accessor = sub {
- my ($attr_name, $type, $accessor) = @_;
-
- my %ACCESSOR_TEMPLATES = (
- 'accessor' => qq{sub {
- \$_[0]->{'$attr_name'} = \$_[1] if scalar(\@_) == 2;
- \$_[0]->{'$attr_name'};
- }},
- 'reader' => qq{sub {
- \$_[0]->{'$attr_name'};
- }},
- 'writer' => qq{sub {
- \$_[0]->{'$attr_name'} = \$_[1];
- }},
- 'predicate' => qq{sub {
- defined \$_[0]->{'$attr_name'} ? 1 : 0;
- }}
- );
+# slots
+
+sub slots { (shift)->name }
+
+# class association
+
+sub attach_to_class {
+ my ($self, $class) = @_;
+ (blessed($class) && $class->isa('Class::MOP::Class'))
+ || confess "You must pass a Class::MOP::Class instance (or a subclass)";
+ weaken($self->{'$!associated_class'} = $class);
+}
+
+sub detach_from_class {
+ my $self = shift;
+ $self->{'$!associated_class'} = undef;
+}
+
+# method association
+
+sub associate_method {
+ my ($self, $method) = @_;
+ push @{$self->{'@!associated_methods'}} => $method;
+}
+
+## Slot management
+
+sub set_value {
+ my ($self, $instance, $value) = @_;
+
+ Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance
+ ->set_slot_value($instance, $self->name, $value);
+}
+
+sub get_value {
+ my ($self, $instance) = @_;
+
+ Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance
+ ->get_slot_value($instance, $self->name);
+}
+
+sub has_value {
+ my ($self, $instance) = @_;
- if (reftype($accessor) && reftype($accessor) eq 'HASH') {
- my ($name, $method) = each %{$accessor};
- return ($name, Class::MOP::Attribute::Accessor->wrap($method));
- }
- else {
- my $method = eval $ACCESSOR_TEMPLATES{$type};
- confess "Could not create the $type for $attr_name CODE(\n" . $ACCESSOR_TEMPLATES{$type} . "\n) : $@" if $@;
- return ($accessor => Class::MOP::Attribute::Accessor->wrap($method));
- }
- };
+ defined Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance
+ ->get_slot_value($instance, $self->name) ? 1 : 0;
+}
+
+sub clear_value {
+ my ($self, $instance) = @_;
+
+ Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance
+ ->deinitialize_slot($instance, $self->name);
+}
- sub install_accessors {
- my ($self, $class) = @_;
- (blessed($class) && $class->isa('Class::MOP::Class'))
- || confess "You must pass a Class::MOP::Class instance (or a subclass)";
- $class->add_method(
- $_inspect_accessor->($self->name, 'accessor' => $self->accessor())
- ) if $self->has_accessor();
-
- $class->add_method(
- $_inspect_accessor->($self->name, 'reader' => $self->reader())
- ) if $self->has_reader();
+## load em up ...
+
+sub accessor_metaclass { 'Class::MOP::Method::Accessor' }
+
+sub process_accessors {
+ my ($self, $type, $accessor, $generate_as_inline_methods) = @_;
+ if (reftype($accessor)) {
+ (reftype($accessor) eq 'HASH')
+ || confess "bad accessor/reader/writer/predicate/clearer format, must be a HASH ref";
+ my ($name, $method) = %{$accessor};
+ $method = $self->accessor_metaclass->wrap($method);
+ $self->associate_method($method);
+ return ($name, $method);
+ }
+ else {
+ my $inline_me = ($generate_as_inline_methods && $self->associated_class->instance_metaclass->is_inlinable);
+ my $method;
+ eval {
+ $method = $self->accessor_metaclass->new(
+ attribute => $self,
+ is_inline => $inline_me,
+ accessor_type => $type,
+ );
+ };
+ confess "Could not create the '$type' method for " . $self->name . " because : $@" if $@;
+ $self->associate_method($method);
+ return ($accessor, $method);
+ }
+}
+
+sub install_accessors {
+ my $self = shift;
+ my $inline = shift;
+ my $class = $self->associated_class;
- $class->add_method(
- $_inspect_accessor->($self->name, 'writer' => $self->writer())
- ) if $self->has_writer();
+ $class->add_method(
+ $self->process_accessors('accessor' => $self->accessor(), $inline)
+ ) if $self->has_accessor();
+
+ $class->add_method(
+ $self->process_accessors('reader' => $self->reader(), $inline)
+ ) if $self->has_reader();
+
+ $class->add_method(
+ $self->process_accessors('writer' => $self->writer(), $inline)
+ ) if $self->has_writer();
+
+ $class->add_method(
+ $self->process_accessors('predicate' => $self->predicate(), $inline)
+ ) if $self->has_predicate();
- $class->add_method(
- $_inspect_accessor->($self->name, 'predicate' => $self->predicate())
- ) if $self->has_predicate();
- return;
- }
+ $class->add_method(
+ $self->process_accessors('clearer' => $self->clearer(), $inline)
+ ) if $self->has_clearer();
+ return;
}
{
}
my $method = $class->get_method($accessor);
$class->remove_method($accessor)
- if (blessed($method) && $method->isa('Class::MOP::Attribute::Accessor'));
+ if (blessed($method) && $method->isa('Class::MOP::Method::Accessor'));
};
sub remove_accessors {
- my ($self, $class) = @_;
- (blessed($class) && $class->isa('Class::MOP::Class'))
- || confess "You must pass a Class::MOP::Class instance (or a subclass)";
- $_remove_accessor->($self->accessor(), $class) if $self->has_accessor();
- $_remove_accessor->($self->reader(), $class) if $self->has_reader();
- $_remove_accessor->($self->writer(), $class) if $self->has_writer();
- $_remove_accessor->($self->predicate(), $class) if $self->has_predicate();
+ my $self = shift;
+ # TODO:
+ # we really need to make sure to remove from the
+ # associates methods here as well. But this is
+ # such a slimly used method, I am not worried
+ # about it right now.
+ $_remove_accessor->($self->accessor(), $self->associated_class()) if $self->has_accessor();
+ $_remove_accessor->($self->reader(), $self->associated_class()) if $self->has_reader();
+ $_remove_accessor->($self->writer(), $self->associated_class()) if $self->has_writer();
+ $_remove_accessor->($self->predicate(), $self->associated_class()) if $self->has_predicate();
+ $_remove_accessor->($self->clearer(), $self->associated_class()) if $self->has_clearer();
return;
}
}
-package Class::MOP::Attribute::Accessor;
-
-use strict;
-use warnings;
-
-use Class::MOP::Method;
-
-our $VERSION = '0.01';
-
-our @ISA = ('Class::MOP::Method');
-
1;
__END__
MyClass->meta->construct_instance(-foo => "Hello There");
+In an init_arg is not assigned, it will automatically use the
+value of C<$name>.
+
=item I<default>
The value of this key is the default value which
=back
-The I<accessor>, I<reader>, I<writer> and I<predicate> keys can
-contain either; the name of the method and an appropriate default
-one will be generated for you, B<or> a HASH ref containing exactly one
-key (which will be used as the name of the method) and one value,
-which should contain a CODE reference which will be installed as
-the method itself.
+The I<accessor>, I<reader>, I<writer>, I<predicate> and I<clearer> keys can
+contain either; the name of the method and an appropriate default one will be
+generated for you, B<or> a HASH ref containing exactly one key (which will be
+used as the name of the method) and one value, which should contain a CODE
+reference which will be installed as the method itself.
=over 4
C<undef>. It will return true (C<1>) if the attribute's value is
defined, and false (C<0>) otherwise.
+=item I<clearer>
+
+This is the a method that will uninitialize the attr, reverting lazy values
+back to their "unfulfilled" state.
+
=back
+=item B<clone (%options)>
+
+=item B<initialize_instance_slot ($instance, $params)>
+
=back
+=head2 Value management
+
+These methods are basically "backdoors" to the instance, which can be used
+to bypass the regular accessors, but still stay within the context of the MOP.
+
+These methods are not for general use, and should only be used if you really
+know what you are doing.
+
+=over 4
+
+=item B<set_value ($instance, $value)>
+
+Set the value without going through the accessor. Note that this may be done to
+even attributes with just read only accessors.
+
+=item B<get_value ($instance)>
+
+Return the value without going through the accessor. Note that this may be done
+even to attributes with just write only accessors.
+
+=item B<has_value ($instance)>
+
+Returns a boolean indicating if the item in the C<$instance> has a value in it.
+This is basically what the default C<predicate> method calls.
+
+=item B<clear_value ($instance)>
+
+This will clear the value in the C<$instance>. This is basically what the default
+C<clearer> would call. Note that this may be done even if the attirbute does not
+have any associated read, write or clear methods.
+
+=back
+
=head2 Informational
These are all basic read-only value accessors for the values
=item B<predicate>
+=item B<clearer>
+
=item B<init_arg>
+=item B<is_default_a_coderef>
+
=item B<default (?$instance)>
As noted in the documentation for C<new> above, if the I<default>
value is a CODE reference, this accessor will pass a single additional
argument C<$instance> into it and return the value.
+=item B<slots>
+
+Returns a list of slots required by the attribute. This is usually
+just one, which is the name of the attribute.
+
=back
=head2 Informational predicates
=item B<has_predicate>
+=item B<has_clearer>
+
=item B<has_init_arg>
=item B<has_default>
=back
+=head2 Class association
+
+These methods allow you to manage the attributes association with
+the class that contains it. These methods should not be used
+lightly, nor are they very magical, they are mostly used internally
+and by metaclass instances.
+
+=over 4
+
+=item B<associated_class>
+
+This returns the metaclass this attribute is associated with.
+
+=item B<attach_to_class ($class)>
+
+This will store a weaken reference to C<$class> internally. You should
+note that just changing the class assocation will not remove the attribute
+from it's old class, and initialize it (and it's accessors) in the new
+C<$class>. It is up to you to do this manually.
+
+=item B<detach_from_class>
+
+This will remove the weakened reference to the class. It does B<not>
+remove the attribute itself from the class (or remove it's accessors),
+you must do that yourself if you want too. Actually if that is what
+you want to do, you should probably be looking at
+L<Class::MOP::Class::remove_attribute> instead.
+
+=back
+
=head2 Attribute Accessor generation
=over 4
-=item B<install_accessors ($class)>
+=item B<accessor_metaclass>
+
+Accessors are generated by an accessor metaclass, which is usually
+a subclass of C<Class::MOP::Method::Accessor>. This method returns
+the name of the accessor metaclass that this attribute uses.
+
+=item B<associate_method ($method)>
+
+This will associate a C<$method> with the given attribute which is
+used internally by the accessor generator.
+
+=item B<associated_methods>
+
+This will return the list of methods which have been associated with
+the C<associate_method> methods.
+
+=item B<install_accessors>
This allows the attribute to generate and install code for it's own
I<accessor/reader/writer/predicate> methods. This is called by
C<Class::MOP::Class::add_attribute>.
-=item B<remove_accessors ($class)>
+This method will call C<process_accessors> for each of the possible
+method types (accessor, reader, writer & predicate).
+
+=item B<process_accessors ($type, $value)>
+
+This takes a C<$type> (accessor, reader, writer or predicate), and
+a C<$value> (the value passed into the constructor for each of the
+different types). It will then either generate the method itself
+(using the C<generate_*_method> methods listed below) or it will
+use the custom method passed through the constructor.
+
+=item B<remove_accessors>
This allows the attribute to remove the method for it's own
-I<accessor/reader/writer/predicate>. This is called by
+I<accessor/reader/writer/predicate/clearer>. This is called by
C<Class::MOP::Class::remove_attribute>.
+NOTE: This does not currently remove methods from the list returned
+by C<associated_methods>, that is on the TODO list.
+
=back
=head2 Introspection
=back
-=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.
+Copyright 2006, 2007 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
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
+
+