use Carp 'confess';
use Scalar::Util 'blessed', 'reftype';
+use Hash::Util 'lock_keys';
use Sub::Name 'subname';
use B 'svref_2object';
-our $VERSION = '0.01';
+our $VERSION = '0.03';
# Self-introspection
-sub meta { $_[0]->initialize($_[0]) }
+sub meta { Class::MOP::Class->initialize($_[0]) }
# Creation
# there is no need to worry about destruction though
# because they should die only when the program dies.
# After all, do package definitions even get reaped?
- my %METAS;
+ my %METAS;
+
sub initialize {
- my ($class, $package_name) = @_;
+ my $class = shift;
+ my $package_name = shift;
(defined $package_name && $package_name)
- || confess "You must pass a package name";
- return $METAS{$package_name} if exists $METAS{$package_name};
- $METAS{$package_name} = $class->construct_class_instance($package_name);
+ || confess "You must pass a package name";
+ # make sure the package name is not blessed
+ $package_name = blessed($package_name) || $package_name;
+ $class->construct_class_instance(':package' => $package_name, @_);
}
# NOTE: (meta-circularity)
# class. All other classes will use the more
# normal &construct_instance.
sub construct_class_instance {
- my ($class, $package_name) = @_;
+ my $class = shift;
+ my %options = @_;
+ my $package_name = $options{':package'};
(defined $package_name && $package_name)
- || confess "You must pass a package name";
+ || confess "You must pass a package name";
+ return $METAS{$package_name} if exists $METAS{$package_name};
$class = blessed($class) || $class;
if ($class =~ /^Class::MOP::/) {
- bless {
- '$:pkg' => $package_name,
- '%:attrs' => {}
+ $METAS{$package_name} = bless {
+ '$:package' => $package_name,
+ '%:attributes' => {},
+ '$:attribute_metaclass' => 'Class::MOP::Attribute',
+ '$:method_metaclass' => 'Class::MOP::Method',
} => $class;
}
else {
- bless $class->meta->construct_instance(':pkg' => $package_name) => $class
+ # NOTE:
+ # it is safe to use meta here because
+ # class will always be a subclass of
+ # Class::MOP::Class, which defines meta
+ $METAS{$package_name} = bless $class->meta->construct_instance(%options) => $class
}
}
}
return $meta;
}
-# Instance Construction
+## Attribute readers
+
+# NOTE:
+# all these attribute readers will be bootstrapped
+# away in the Class::MOP bootstrap section
+
+sub name { $_[0]->{'$:package'} }
+sub get_attribute_map { $_[0]->{'%:attributes'} }
+sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} }
+sub method_metaclass { $_[0]->{'$:method_metaclass'} }
+
+# Instance Construction & Cloning
+
+sub new_object {
+ my $class = shift;
+ # NOTE:
+ # we need to protect the integrity of the
+ # Class::MOP::Class singletons here, so we
+ # delegate this to &construct_class_instance
+ # which will deal with the singletons
+ return $class->construct_class_instance(@_)
+ if $class->name->isa('Class::MOP::Class');
+ bless $class->construct_instance(@_) => $class->name;
+}
sub construct_instance {
my ($class, %params) = @_;
my $instance = {};
- 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;
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
+ 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
+ $val ||= $attr->default($instance) if $attr->has_default();
$instance->{$attr->name} = $val;
}
return $instance;
}
+sub clone_object {
+ my $class = shift;
+ my $instance = shift;
+ (blessed($instance) && $instance->isa($class->name))
+ || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")";
+ # NOTE:
+ # we need to protect the integrity of the
+ # Class::MOP::Class singletons here, they
+ # should not be cloned
+ return $instance if $instance->isa('Class::MOP::Class');
+ bless $class->clone_instance($instance, @_) => blessed($instance);
+}
+
+#{
+# sub _deep_clone {
+# my ($object, $cache) = @_;
+# return $object unless ref($object);
+# # check for an active cache
+# return _deep_clone_ref($object, ($cache = {}), 'HASH') if not defined $cache;
+# # if we have it in the cache them return the cached clone
+# return $cache->{$object} if exists $cache->{$object};
+# # now try it as an object, which will in
+# # turn try it as ref if its not an object
+# # and store it in case we run into a circular ref
+# $cache->{$object} = _deep_clone_object($object, $cache);
+# }
+#
+# sub _deep_clone_object {
+# my ($object, $cache) = @_;
+# # check to see if its an object, with a clone method
+# # or if we have an object, with no clone method, then
+# # we will respect its encapsulation, and not muck with
+# # its internals. Basically, we assume it does not want
+# # to be cloned
+# return $cache->{$object} = ($object->can('clone') ? $object->clone() : $object)
+# if blessed($object);
+# return $cache->{$object} = _deep_clone_ref($object, $cache);
+# }
+#
+# sub _deep_clone_ref {
+# my ($object, $cache, $ref_type) = @_;
+# $ref_type ||= ref($object);
+# my ($clone, $tied);
+# if ($ref_type eq 'HASH') {
+# $clone = {};
+# tie %{$clone}, ref $tied if $tied = tied(%{$object});
+# %{$clone} = map { ref($_) ? _deep_clone($_, $cache) : $_ } %{$object};
+# }
+# elsif ($ref_type eq 'ARRAY') {
+# $clone = [];
+# tie @{$clone}, ref $tied if $tied = tied(@{$object});
+# @{$clone} = map { ref($_) ? _deep_clone($_, $cache) : $_ } @{$object};
+# }
+# elsif ($ref_type eq 'REF' or $ref_type eq 'SCALAR') {
+# my $var = "";
+# $clone = \$var;
+# tie ${$clone}, ref $tied if $tied = tied(${$object});
+# ${$clone} = _deep_clone(${$object}, $cache);
+# }
+# else {
+# # shallow copy reference to code, glob, regex
+# $clone = $object;
+# }
+# # store it in our cache
+# $cache->{$object} = $clone;
+# # and return the clone
+# return $clone;
+# }
+#}
+
+sub clone_instance {
+ my ($class, $instance, %params) = @_;
+ (blessed($instance))
+ || confess "You can only clone instances, \$self is not a blessed instance";
+ # NOTE:
+ # this should actually do a deep clone
+ # instead of this cheap hack. I will
+ # add that in later.
+ # (use the Class::Cloneable::Util code)
+ my $clone = { %{$instance} }; #_deep_clone($instance);
+ foreach my $attr ($class->compute_all_applicable_attributes()) {
+ my $init_arg = $attr->init_arg();
+ # try to fetch the init arg from the %params ...
+ $clone->{$attr->name} = $params{$init_arg}
+ if exists $params{$init_arg};
+ }
+ return $clone;
+}
+
# Informational
-sub name { $_[0]->{'$:pkg'} }
+# &name should be here too, but it is above
+# because it gets bootstrapped away
sub version {
my $self = shift;
## Attributes
sub add_attribute {
- my ($self,$attribute) = @_;
- (blessed($attribute) && $attribute->isa('Class::MOP::Attribute'))
- || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
+ my $self = shift;
+ # either we have an attribute object already
+ # or we need to create one from the args provided
+ my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
+ # make sure it is derived from the correct type though
+ ($attribute->isa('Class::MOP::Attribute'))
+ || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
$attribute->attach_to_class($self);
$attribute->install_accessors();
- $self->{'%:attrs'}->{$attribute->name} = $attribute;
+ $self->get_attribute_map->{$attribute->name} = $attribute;
}
sub has_attribute {
my ($self, $attribute_name) = @_;
(defined $attribute_name && $attribute_name)
|| confess "You must define an attribute name";
- exists $self->{'%:attrs'}->{$attribute_name} ? 1 : 0;
+ exists $self->get_attribute_map->{$attribute_name} ? 1 : 0;
}
sub get_attribute {
my ($self, $attribute_name) = @_;
(defined $attribute_name && $attribute_name)
|| confess "You must define an attribute name";
- return $self->{'%:attrs'}->{$attribute_name}
+ return $self->get_attribute_map->{$attribute_name}
if $self->has_attribute($attribute_name);
}
my ($self, $attribute_name) = @_;
(defined $attribute_name && $attribute_name)
|| confess "You must define an attribute name";
- my $removed_attribute = $self->{'%:attrs'}->{$attribute_name};
- delete $self->{'%:attrs'}->{$attribute_name}
+ my $removed_attribute = $self->get_attribute_map->{$attribute_name};
+ delete $self->get_attribute_map->{$attribute_name}
if defined $removed_attribute;
$removed_attribute->remove_accessors();
$removed_attribute->detach_from_class();
sub get_attribute_list {
my $self = shift;
- keys %{$self->{'%:attrs'}};
+ keys %{$self->get_attribute_map};
}
sub compute_all_applicable_attributes {
foreach my $attr_name ($meta->get_attribute_list()) {
next if exists $seen_attr{$attr_name};
$seen_attr{$attr_name}++;
- push @attrs => {
- name => $attr_name,
- class => $class,
- attribute => $meta->get_attribute($attr_name)
- };
+ push @attrs => $meta->get_attribute($attr_name);
}
}
return @attrs;
This initializes and returns returns a B<Class::MOP::Class> object
for a given a C<$package_name>.
-=item B<construct_class_instance ($package_name)>
+=item B<construct_class_instance (%options)>
This will construct an instance of B<Class::MOP::Class>, it is
here so that we can actually "tie the knot" for B<Class::MOP::Class>
=back
-=head2 Object instance construction
-
-This method is used to construct an instace structure suitable for
-C<bless>-ing into your package of choice. It works in conjunction
-with the Attribute protocol to collect all applicable attributes.
+=head2 Object instance construction and cloning
-This method is B<entirely optional>, it is up to you whether you want
-to use it or not.
+These methods are B<entirely optional>, it is up to you whether you want
+to use them or not.
=over 4
+=item B<new_object (%params)>
+
+This is a convience method for creating a new object of the class, and
+blessing it into the appropriate package as well. Ideally your class
+would call a C<new> this method like so:
+
+ sub MyClass::new {
+ my ($class, %param) = @_;
+ $class->meta->new_object(%params);
+ }
+
+Of course the ideal place for this would actually be in C<UNIVERSAL::>
+but that is considered bad style, so we do not do that.
+
=item B<construct_instance (%params)>
+This method is used to construct an instace structure suitable for
+C<bless>-ing into your package of choice. It works in conjunction
+with the Attribute protocol to collect all applicable attributes.
+
This will construct and instance using a HASH ref as storage
(currently only HASH references are supported). This will collect all
the applicable attributes and layout out the fields in the HASH ref,
in C<%params> or any default value or initializer found in the
attribute meta-object.
+=item B<clone_object ($instance, %params)>
+
+This is a convience method for cloning an object instance, then
+blessing it into the appropriate package. Ideally your class
+would call a C<clone> this method like so:
+
+ sub MyClass::clone {
+ my ($self, %param) = @_;
+ $self->meta->clone_object($self, %params);
+ }
+
+Of course the ideal place for this would actually be in C<UNIVERSAL::>
+but that is considered bad style, so we do not do that.
+
+=item B<clone_instance($instance, %params)>
+
+This method is a compliment of C<construct_instance> (which means if
+you override C<construct_instance>, you need to override this one too).
+
+This method will clone the C<$instance> structure created by the
+C<construct_instance> method, and apply any C<%params> passed to it
+to change the attribute values. The structure returned is (like with
+C<construct_instance>) an unC<bless>ed HASH reference, it is your
+responsibility to then bless this cloned structure into the right
+class.
+
=back
=head2 Informational
relationships of the class the B<Class::MOP::Class> instance is
associated with. Basically, it can get and set the C<@ISA> for you.
+B<NOTE:>
+Perl will occasionally perform some C<@ISA> and method caching, if
+you decide to change your superclass relationship at runtime (which
+is quite insane and very much not recommened), then you should be
+aware of this and the fact that this module does not make any
+attempt to address this issue.
+
=item B<class_precedence_list>
This computes the a list of all the class's ancestors in the same order
=over 4
+=item B<method_metaclass>
+
=item B<add_method ($method_name, $method)>
This will take a C<$method_name> and CODE reference to that
=over 4
+=item B<attribute_metaclass>
+
+=item B<get_attribute_map>
+
=item B<add_attribute ($attribute_name, $attribute_meta_object)>
This stores a C<$attribute_meta_object> in the B<Class::MOP::Class>
=item B<compute_all_applicable_attributes>
-This will traverse the inheritance heirachy and return a list of HASH
-references for all the applicable attributes for this class. The HASH
-references will contain the following information; the attribute name,
-the class which the attribute is associated with and the actual
-attribute meta-object.
+This will traverse the inheritance heirachy and return a list of all
+the applicable attributes for this class. It does not construct a
+HASH reference like C<compute_all_applicable_methods> because all
+that same information is discoverable through the attribute
+meta-object itself.
=back
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