2 package Class::MOP::Class;
7 use Class::MOP::Immutable;
8 use Class::MOP::Instance;
9 use Class::MOP::Method::Wrapped;
12 use Scalar::Util 'blessed', 'weaken';
14 our $VERSION = '0.77_01';
15 $VERSION = eval $VERSION;
16 our $AUTHORITY = 'cpan:STEVAN';
18 use base 'Class::MOP::Module';
28 $package_name = shift;
31 $package_name = $options{package};
34 (defined $package_name && $package_name && !ref($package_name))
35 || confess "You must pass a package name and it cannot be blessed";
37 return Class::MOP::get_metaclass_by_name($package_name)
38 || $class->construct_class_instance(package => $package_name, @_);
41 # NOTE: (meta-circularity)
42 # this is a special form of &construct_instance
43 # (see below), which is used to construct class
44 # meta-object instances for any Class::MOP::*
45 # class. All other classes will use the more
46 # normal &construct_instance.
47 sub construct_class_instance {
49 my $options = @_ == 1 ? $_[0] : {@_};
50 my $package_name = $options->{package};
51 (defined $package_name && $package_name)
52 || confess "You must pass a package name";
54 # return the metaclass if we have it cached,
55 # and it is still defined (it has not been
56 # reaped by DESTROY yet, which can happen
57 # annoyingly enough during global destruction)
59 if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) {
64 # we need to deal with the possibility
65 # of class immutability here, and then
66 # get the name of the class appropriately
68 ? ($class->is_immutable
69 ? $class->get_mutable_metaclass_name()
73 # now create the metaclass
75 if ($class eq 'Class::MOP::Class') {
77 $meta = $class->_new($options)
81 # it is safe to use meta here because
82 # class will always be a subclass of
83 # Class::MOP::Class, which defines meta
84 $meta = $class->meta->construct_instance($options)
87 # and check the metaclass compatibility
88 $meta->check_metaclass_compatibility();
90 Class::MOP::store_metaclass_by_name($package_name, $meta);
93 # we need to weaken any anon classes
94 # so that they can call DESTROY properly
95 Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class;
102 my $options = @_ == 1 ? $_[0] : {@_};
105 # inherited from Class::MOP::Package
106 'package' => $options->{package},
109 # since the following attributes will
110 # actually be loaded from the symbol
111 # table, and actually bypass the instance
112 # entirely, we can just leave these things
113 # listed here for reference, because they
114 # should not actually have a value associated
116 'namespace' => \undef,
118 # inherited from Class::MOP::Module
120 'authority' => \undef,
122 # defined in Class::MOP::Class
123 'superclasses' => \undef,
127 'attribute_metaclass' => $options->{'attribute_metaclass'}
128 || 'Class::MOP::Attribute',
129 'method_metaclass' => $options->{'method_metaclass'}
130 || 'Class::MOP::Method',
131 'wrapped_method_metaclass' => $options->{'wrapped_method_metaclass'}
132 || 'Class::MOP::Method::Wrapped',
133 'instance_metaclass' => $options->{'instance_metaclass'}
134 || 'Class::MOP::Instance',
138 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
139 sub update_package_cache_flag {
142 # we can manually update the cache number
143 # since we are actually adding the method
144 # to our cache as well. This avoids us
145 # having to regenerate the method_map.
147 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
150 sub check_metaclass_compatibility {
153 # this is always okay ...
154 return if ref($self) eq 'Class::MOP::Class' &&
155 $self->instance_metaclass eq 'Class::MOP::Instance';
157 my @class_list = $self->linearized_isa;
158 shift @class_list; # shift off $self->name
160 foreach my $superclass_name (@class_list) {
161 my $super_meta = Class::MOP::get_metaclass_by_name($superclass_name) || next;
164 # we need to deal with the possibility
165 # of class immutability here, and then
166 # get the name of the class appropriately
168 = $super_meta->is_immutable
169 ? $super_meta->get_mutable_metaclass_name()
172 ($self->isa($super_meta_type))
173 || confess $self->name . "->meta => (" . (ref($self)) . ")" .
174 " is not compatible with the " .
175 $superclass_name . "->meta => (" . ($super_meta_type) . ")";
177 # we also need to check that instance metaclasses
178 # are compatibile in the same the class.
179 ($self->instance_metaclass->isa($super_meta->instance_metaclass))
180 || confess $self->name . "->meta->instance_metaclass => (" . ($self->instance_metaclass) . ")" .
181 " is not compatible with the " .
182 $superclass_name . "->meta->instance_metaclass => (" . ($super_meta->instance_metaclass) . ")";
186 # backwards compat for stevan's inability to spell ;)
187 sub check_metaclass_compatability {
189 $self->check_metaclass_compatibility(@_);
196 # this should be sufficient, if you have a
197 # use case where it is not, write a test and
199 my $ANON_CLASS_SERIAL = 0;
202 # we need a sufficiently annoying prefix
203 # this should suffice for now, this is
204 # used in a couple of places below, so
205 # need to put it up here for now.
206 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
210 no warnings 'uninitialized';
211 $self->name =~ /^$ANON_CLASS_PREFIX/;
214 sub create_anon_class {
215 my ($class, %options) = @_;
216 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
217 return $class->create($package_name, %options);
221 # this will only get called for
222 # anon-classes, all other calls
223 # are assumed to occur during
224 # global destruction and so don't
225 # really need to be handled explicitly
229 return if Class::MOP::in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
231 no warnings 'uninitialized';
232 return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
233 # Moose does a weird thing where it replaces the metaclass for
234 # class when fixing metaclass incompatibility. In that case,
235 # we don't want to clean out the namespace now. We can detect
236 # that because Moose will explicitly update the singleton
237 # cache in Class::MOP.
238 my $current_meta = Class::MOP::get_metaclass_by_name($self->name);
239 return if $current_meta ne $self;
241 my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
243 foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
244 delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
246 delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
251 # creating classes with MOP ...
254 my ( $class, @args ) = @_;
256 unshift @args, 'package' if @args % 2 == 1;
258 my (%options) = @args;
259 my $package_name = $options{package};
261 (ref $options{superclasses} eq 'ARRAY')
262 || confess "You must pass an ARRAY ref of superclasses"
263 if exists $options{superclasses};
265 (ref $options{attributes} eq 'ARRAY')
266 || confess "You must pass an ARRAY ref of attributes"
267 if exists $options{attributes};
269 (ref $options{methods} eq 'HASH')
270 || confess "You must pass a HASH ref of methods"
271 if exists $options{methods};
273 $class->SUPER::create(%options);
275 my (%initialize_options) = @args;
276 delete @initialize_options{qw(
284 my $meta = $class->initialize( $package_name => %initialize_options );
287 $meta->add_method('meta' => sub {
288 $class->initialize(ref($_[0]) || $_[0]);
291 $meta->superclasses(@{$options{superclasses}})
292 if exists $options{superclasses};
294 # process attributes first, so that they can
295 # install accessors, but locally defined methods
296 # can then overwrite them. It is maybe a little odd, but
297 # I think this should be the order of things.
298 if (exists $options{attributes}) {
299 foreach my $attr (@{$options{attributes}}) {
300 $meta->add_attribute($attr);
303 if (exists $options{methods}) {
304 foreach my $method_name (keys %{$options{methods}}) {
305 $meta->add_method($method_name, $options{methods}->{$method_name});
314 # all these attribute readers will be bootstrapped
315 # away in the Class::MOP bootstrap section
317 sub get_attribute_map { $_[0]->{'attributes'} }
318 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
319 sub method_metaclass { $_[0]->{'method_metaclass'} }
320 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
321 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
323 # Instance Construction & Cloning
329 # we need to protect the integrity of the
330 # Class::MOP::Class singletons here, so we
331 # delegate this to &construct_class_instance
332 # which will deal with the singletons
333 return $class->construct_class_instance(@_)
334 if $class->name->isa('Class::MOP::Class');
335 return $class->construct_instance(@_);
338 sub construct_instance {
340 my $params = @_ == 1 ? $_[0] : {@_};
341 my $meta_instance = $class->get_meta_instance();
342 my $instance = $meta_instance->create_instance();
343 foreach my $attr ($class->compute_all_applicable_attributes()) {
344 $attr->initialize_instance_slot($meta_instance, $instance, $params);
347 # this will only work for a HASH instance type
348 if ($class->is_anon_class) {
349 (Scalar::Util::reftype($instance) eq 'HASH')
350 || confess "Currently only HASH based instances are supported with instance of anon-classes";
352 # At some point we should make this official
353 # as a reserved slot name, but right now I am
354 # going to keep it here.
355 # my $RESERVED_MOP_SLOT = '__MOP__';
356 $instance->{'__MOP__'} = $class;
362 sub get_meta_instance {
364 $self->{'_meta_instance'} ||= $self->create_meta_instance();
367 sub create_meta_instance {
370 my $instance = $self->instance_metaclass->new(
371 associated_metaclass => $self,
372 attributes => [ $self->compute_all_applicable_attributes() ],
375 $self->add_meta_instance_dependencies()
376 if $instance->is_dependent_on_superclasses();
383 my $instance = shift;
384 (blessed($instance) && $instance->isa($class->name))
385 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
388 # we need to protect the integrity of the
389 # Class::MOP::Class singletons here, they
390 # should not be cloned.
391 return $instance if $instance->isa('Class::MOP::Class');
392 $class->clone_instance($instance, @_);
396 my ($class, $instance, %params) = @_;
398 || confess "You can only clone instances, ($instance) is not a blessed instance";
399 my $meta_instance = $class->get_meta_instance();
400 my $clone = $meta_instance->clone_instance($instance);
401 foreach my $attr ($class->compute_all_applicable_attributes()) {
402 if ( defined( my $init_arg = $attr->init_arg ) ) {
403 if (exists $params{$init_arg}) {
404 $attr->set_value($clone, $params{$init_arg});
411 sub rebless_instance {
412 my ($self, $instance, %params) = @_;
415 if ($instance->can('meta')) {
416 ($instance->meta->isa('Class::MOP::Class'))
417 || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
418 $old_metaclass = $instance->meta;
421 $old_metaclass = $self->initialize(ref($instance));
424 my $meta_instance = $self->get_meta_instance();
426 $self->name->isa($old_metaclass->name)
427 || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
430 $meta_instance->rebless_instance_structure($instance, $self);
432 foreach my $attr ( $self->compute_all_applicable_attributes ) {
433 if ( $attr->has_value($instance) ) {
434 if ( defined( my $init_arg = $attr->init_arg ) ) {
435 $params{$init_arg} = $attr->get_value($instance)
436 unless exists $params{$init_arg};
439 $attr->set_value($instance, $attr->get_value($instance));
444 foreach my $attr ($self->compute_all_applicable_attributes) {
445 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
455 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
458 @{$self->get_package_symbol($var_spec)} = @supers;
461 # on 5.8 and below, we need to call
462 # a method to get Perl to detect
463 # a cycle in the class hierarchy
464 my $class = $self->name;
468 # we need to check the metaclass
469 # compatibility here so that we can
470 # be sure that the superclass is
471 # not potentially creating an issues
472 # we don't know about
474 $self->check_metaclass_compatibility();
475 $self->update_meta_instance_dependencies();
477 @{$self->get_package_symbol($var_spec)};
483 my $super_class = $self->name;
485 if ( Class::MOP::HAVE_ISAREV() ) {
486 return @{ $super_class->mro::get_isarev() };
490 my $find_derived_classes;
491 $find_derived_classes = sub {
492 my ($outer_class) = @_;
494 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
497 for my $symbol ( keys %$symbol_table_hashref ) {
498 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
499 my $inner_class = $1;
501 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
505 ? "${outer_class}::$inner_class"
508 if ( $class->isa($super_class) and $class ne $super_class ) {
509 push @derived_classes, $class;
512 next SYMBOL if $class eq 'main'; # skip 'main::*'
514 $find_derived_classes->($class);
518 my $root_class = q{};
519 $find_derived_classes->($root_class);
521 undef $find_derived_classes;
523 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
525 return @derived_classes;
531 return @{ mro::get_linear_isa( (shift)->name ) };
534 sub class_precedence_list {
536 my $name = $self->name;
538 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
540 # We need to check for circular inheritance here
541 # if we are are not on 5.10, cause 5.8 detects it
542 # late. This will do nothing if all is well, and
543 # blow up otherwise. Yes, it's an ugly hack, better
544 # suggestions are welcome.
546 ($name || return)->isa('This is a test for circular inheritance')
549 # if our mro is c3, we can
550 # just grab the linear_isa
551 if (mro::get_mro($name) eq 'c3') {
552 return @{ mro::get_linear_isa($name) }
556 # we can't grab the linear_isa for dfs
557 # since it has all the duplicates
562 $self->initialize($_)->class_precedence_list()
563 } $self->superclasses()
570 sub wrap_method_body {
571 my ( $self, %args ) = @_;
573 ('CODE' eq ref $args{body})
574 || confess "Your code block must be a CODE reference";
576 $self->method_metaclass->wrap(
577 package_name => $self->name,
583 my ($self, $method_name, $method) = @_;
584 (defined $method_name && $method_name)
585 || confess "You must define a method name";
588 if (blessed($method)) {
589 $body = $method->body;
590 if ($method->package_name ne $self->name) {
591 $method = $method->clone(
592 package_name => $self->name,
594 ) if $method->can('clone');
599 $method = $self->wrap_method_body( body => $body, name => $method_name );
602 $method->attach_to_class($self);
604 # This used to call get_method_map, which meant we would build all
605 # the method objects for the class just because we added one
606 # method. This is hackier, but quicker too.
607 $self->{methods}{$method_name} = $method;
609 my $full_method_name = ($self->name . '::' . $method_name);
610 $self->add_package_symbol(
611 { sigil => '&', type => 'CODE', name => $method_name },
612 Class::MOP::subname($full_method_name => $body)
617 my $fetch_and_prepare_method = sub {
618 my ($self, $method_name) = @_;
619 my $wrapped_metaclass = $self->wrapped_method_metaclass;
621 my $method = $self->get_method($method_name);
622 # if we dont have local ...
624 # try to find the next method
625 $method = $self->find_next_method_by_name($method_name);
626 # die if it does not exist
628 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
629 # and now make sure to wrap it
630 # even if it is already wrapped
631 # because we need a new sub ref
632 $method = $wrapped_metaclass->wrap($method);
635 # now make sure we wrap it properly
636 $method = $wrapped_metaclass->wrap($method)
637 unless $method->isa($wrapped_metaclass);
639 $self->add_method($method_name => $method);
643 sub add_before_method_modifier {
644 my ($self, $method_name, $method_modifier) = @_;
645 (defined $method_name && $method_name)
646 || confess "You must pass in a method name";
647 my $method = $fetch_and_prepare_method->($self, $method_name);
648 $method->add_before_modifier(
649 Class::MOP::subname(':before' => $method_modifier)
653 sub add_after_method_modifier {
654 my ($self, $method_name, $method_modifier) = @_;
655 (defined $method_name && $method_name)
656 || confess "You must pass in a method name";
657 my $method = $fetch_and_prepare_method->($self, $method_name);
658 $method->add_after_modifier(
659 Class::MOP::subname(':after' => $method_modifier)
663 sub add_around_method_modifier {
664 my ($self, $method_name, $method_modifier) = @_;
665 (defined $method_name && $method_name)
666 || confess "You must pass in a method name";
667 my $method = $fetch_and_prepare_method->($self, $method_name);
668 $method->add_around_modifier(
669 Class::MOP::subname(':around' => $method_modifier)
674 # the methods above used to be named like this:
675 # ${pkg}::${method}:(before|after|around)
676 # but this proved problematic when using one modifier
677 # to wrap multiple methods (something which is likely
678 # to happen pretty regularly IMO). So instead of naming
679 # it like this, I have chosen to just name them purely
680 # with their modifier names, like so:
681 # :(before|after|around)
682 # The fact is that in a stack trace, it will be fairly
683 # evident from the context what method they are attached
684 # to, and so don't need the fully qualified name.
690 $self->add_method(@_);
694 my ($self, $method_name) = @_;
695 (defined $method_name && $method_name)
696 || confess "You must define a method name";
698 exists $self->{methods}{$method_name} || exists $self->get_method_map->{$method_name};
702 my ($self, $method_name) = @_;
703 (defined $method_name && $method_name)
704 || confess "You must define a method name";
706 return $self->{methods}{$method_name} || $self->get_method_map->{$method_name};
710 my ($self, $method_name) = @_;
711 (defined $method_name && $method_name)
712 || confess "You must define a method name";
714 my $removed_method = delete $self->get_method_map->{$method_name};
716 $self->remove_package_symbol(
717 { sigil => '&', type => 'CODE', name => $method_name }
720 $removed_method->detach_from_class if $removed_method;
722 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
724 return $removed_method;
727 sub get_method_list {
729 keys %{$self->get_method_map};
732 sub find_method_by_name {
733 my ($self, $method_name) = @_;
734 (defined $method_name && $method_name)
735 || confess "You must define a method name to find";
736 foreach my $class ($self->linearized_isa) {
737 # fetch the meta-class ...
738 my $meta = $self->initialize($class);
739 return $meta->get_method($method_name)
740 if $meta->has_method($method_name);
745 sub get_all_methods {
747 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
748 return values %methods;
752 sub compute_all_applicable_methods {
756 class => $_->package_name,
757 code => $_, # sigh, overloading
759 } shift->get_all_methods(@_);
762 sub get_all_method_names {
765 grep { $uniq{$_}++ == 0 } map { $_->name } $self->get_all_methods;
768 sub find_all_methods_by_name {
769 my ($self, $method_name) = @_;
770 (defined $method_name && $method_name)
771 || confess "You must define a method name to find";
773 foreach my $class ($self->linearized_isa) {
774 # fetch the meta-class ...
775 my $meta = $self->initialize($class);
777 name => $method_name,
779 code => $meta->get_method($method_name)
780 } if $meta->has_method($method_name);
785 sub find_next_method_by_name {
786 my ($self, $method_name) = @_;
787 (defined $method_name && $method_name)
788 || confess "You must define a method name to find";
789 my @cpl = $self->linearized_isa;
790 shift @cpl; # discard ourselves
791 foreach my $class (@cpl) {
792 # fetch the meta-class ...
793 my $meta = $self->initialize($class);
794 return $meta->get_method($method_name)
795 if $meta->has_method($method_name);
804 # either we have an attribute object already
805 # or we need to create one from the args provided
806 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
807 # make sure it is derived from the correct type though
808 ($attribute->isa('Class::MOP::Attribute'))
809 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
811 # first we attach our new attribute
812 # because it might need certain information
813 # about the class which it is attached to
814 $attribute->attach_to_class($self);
816 # then we remove attributes of a conflicting
817 # name here so that we can properly detach
818 # the old attr object, and remove any
819 # accessors it would have generated
820 if ( $self->has_attribute($attribute->name) ) {
821 $self->remove_attribute($attribute->name);
823 $self->invalidate_meta_instances();
826 # then onto installing the new accessors
827 $self->get_attribute_map->{$attribute->name} = $attribute;
829 # invalidate package flag here
830 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
832 $self->remove_attribute($attribute->name);
839 sub update_meta_instance_dependencies {
842 if ( $self->{meta_instance_dependencies} ) {
843 return $self->add_meta_instance_dependencies;
847 sub add_meta_instance_dependencies {
850 $self->remove_meta_instance_depdendencies;
852 my @attrs = $self->compute_all_applicable_attributes();
855 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
857 foreach my $class ( @classes ) {
858 $class->add_dependent_meta_instance($self);
861 $self->{meta_instance_dependencies} = \@classes;
864 sub remove_meta_instance_depdendencies {
867 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
868 foreach my $class ( @$classes ) {
869 $class->remove_dependent_meta_instance($self);
879 sub add_dependent_meta_instance {
880 my ( $self, $metaclass ) = @_;
881 push @{ $self->{dependent_meta_instances} }, $metaclass;
884 sub remove_dependent_meta_instance {
885 my ( $self, $metaclass ) = @_;
886 my $name = $metaclass->name;
887 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
890 sub invalidate_meta_instances {
892 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
895 sub invalidate_meta_instance {
897 undef $self->{_meta_instance};
901 my ($self, $attribute_name) = @_;
902 (defined $attribute_name && $attribute_name)
903 || confess "You must define an attribute name";
904 exists $self->get_attribute_map->{$attribute_name};
908 my ($self, $attribute_name) = @_;
909 (defined $attribute_name && $attribute_name)
910 || confess "You must define an attribute name";
911 return $self->get_attribute_map->{$attribute_name}
913 # this will return undef anyway, so no need ...
914 # if $self->has_attribute($attribute_name);
918 sub remove_attribute {
919 my ($self, $attribute_name) = @_;
920 (defined $attribute_name && $attribute_name)
921 || confess "You must define an attribute name";
922 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
923 return unless defined $removed_attribute;
924 delete $self->get_attribute_map->{$attribute_name};
925 $self->invalidate_meta_instances();
926 $removed_attribute->remove_accessors();
927 $removed_attribute->detach_from_class();
928 return $removed_attribute;
931 sub get_attribute_list {
933 keys %{$self->get_attribute_map};
936 sub get_all_attributes {
937 shift->compute_all_applicable_attributes(@_);
940 sub compute_all_applicable_attributes {
942 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
943 return values %attrs;
946 sub find_attribute_by_name {
947 my ($self, $attr_name) = @_;
948 foreach my $class ($self->linearized_isa) {
949 # fetch the meta-class ...
950 my $meta = $self->initialize($class);
951 return $meta->get_attribute($attr_name)
952 if $meta->has_attribute($attr_name);
957 # check if we can reinitialize
961 # if any local attr is defined
962 return if $self->get_attribute_list;
964 # or any non-declared methods
965 if ( my @methods = values %{ $self->get_method_map } ) {
966 my $metaclass = $self->method_metaclass;
967 foreach my $method ( @methods ) {
968 return if $method->isa("Class::MOP::Method::Generated");
969 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
979 sub is_immutable { 0 }
982 # Why I changed this (groditi)
983 # - One Metaclass may have many Classes through many Metaclass instances
984 # - One Metaclass should only have one Immutable Transformer instance
985 # - Each Class may have different Immutabilizing options
986 # - Therefore each Metaclass instance may have different Immutabilizing options
987 # - We need to store one Immutable Transformer instance per Metaclass
988 # - We need to store one set of Immutable Transformer options per Class
989 # - Upon make_mutable we may delete the Immutabilizing options
990 # - We could clean the immutable Transformer instance when there is no more
991 # immutable Classes of that type, but we can also keep it in case
992 # another class with this same Metaclass becomes immutable. It is a case
993 # of trading of storing an instance to avoid unnecessary instantiations of
994 # Immutable Transformers. You may view this as a memory leak, however
995 # Because we have few Metaclasses, in practice it seems acceptable
996 # - To allow Immutable Transformers instances to be cleaned up we could weaken
997 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
1001 my %IMMUTABLE_TRANSFORMERS;
1002 my %IMMUTABLE_OPTIONS;
1004 sub get_immutable_options {
1006 return if $self->is_mutable;
1007 confess "unable to find immutabilizing options"
1008 unless exists $IMMUTABLE_OPTIONS{$self->name};
1009 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1010 delete $options{IMMUTABLE_TRANSFORMER};
1014 sub get_immutable_transformer {
1016 if( $self->is_mutable ){
1017 return $IMMUTABLE_TRANSFORMERS{$self->name} ||= $self->create_immutable_transformer;
1019 confess "unable to find transformer for immutable class"
1020 unless exists $IMMUTABLE_OPTIONS{$self->name};
1021 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1024 sub make_immutable {
1028 my $transformer = $self->get_immutable_transformer;
1029 $transformer->make_metaclass_immutable($self, \%options);
1030 $IMMUTABLE_OPTIONS{$self->name} =
1031 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1033 if( exists $options{debug} && $options{debug} ){
1034 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1035 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1043 return if $self->is_mutable;
1044 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1045 confess "unable to find immutabilizing options" unless ref $options;
1046 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1047 $transformer->make_metaclass_mutable($self, $options);
1052 sub create_immutable_transformer {
1054 my $class = Class::MOP::Immutable->new($self, {
1055 read_only => [qw/superclasses/],
1062 remove_package_symbol
1065 class_precedence_list => 'ARRAY',
1066 linearized_isa => 'ARRAY', # FIXME perl 5.10 memoizes this on its own, no need?
1067 get_all_methods => 'ARRAY',
1068 get_all_method_names => 'ARRAY',
1069 #get_all_attributes => 'ARRAY', # it's an alias, no need, but maybe in the future
1070 compute_all_applicable_attributes => 'ARRAY',
1071 get_meta_instance => 'SCALAR',
1072 get_method_map => 'SCALAR',
1075 # this is ugly, but so are typeglobs,
1076 # so whattayahgonnadoboutit
1079 add_package_symbol => sub {
1080 my $original = shift;
1081 confess "Cannot add package symbols to an immutable metaclass"
1082 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1084 # This is a workaround for a bug in 5.8.1 which thinks that
1085 # goto $original->body
1086 # is trying to go to a label
1087 my $body = $original->body;
1103 Class::MOP::Class - Class Meta Object
1107 # assuming that class Foo
1108 # has been defined, you can
1110 # use this for introspection ...
1112 # add a method to Foo ...
1113 Foo->meta->add_method('bar' => sub { ... })
1115 # get a list of all the classes searched
1116 # the method dispatcher in the correct order
1117 Foo->meta->class_precedence_list()
1119 # remove a method from Foo
1120 Foo->meta->remove_method('bar');
1122 # or use this to actually create classes ...
1124 Class::MOP::Class->create('Bar' => (
1126 superclasses => [ 'Foo' ],
1128 Class::MOP:::Attribute->new('$bar'),
1129 Class::MOP:::Attribute->new('$baz'),
1132 calculate_bar => sub { ... },
1133 construct_baz => sub { ... }
1139 This is the largest and currently most complex part of the Perl 5
1140 meta-object protocol. It controls the introspection and
1141 manipulation of Perl 5 classes (and it can create them too). The
1142 best way to understand what this module can do, is to read the
1143 documentation for each of it's methods.
1147 B<Class::MOP::Class> is a subclass of L<Class::MOP::Module>
1151 =head2 Self Introspection
1157 This will return a B<Class::MOP::Class> instance which is related
1158 to this class. Thereby allowing B<Class::MOP::Class> to actually
1161 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1162 bootstrap this module by installing a number of attribute meta-objects
1163 into it's metaclass. This will allow this class to reap all the benifits
1164 of the MOP when subclassing it.
1168 =head2 Class construction
1170 These methods will handle creating B<Class::MOP::Class> objects,
1171 which can be used to both create new classes, and analyze
1172 pre-existing classes.
1174 This module will internally store references to all the instances
1175 you create with these methods, so that they do not need to be
1176 created any more than nessecary. Basically, they are singletons.
1180 =item B<create ($package_name,
1181 version =E<gt> ?$version,
1182 authority =E<gt> ?$authority,
1183 superclasses =E<gt> ?@superclasses,
1184 methods =E<gt> ?%methods,
1185 attributes =E<gt> ?%attributes)>
1187 This returns a B<Class::MOP::Class> object, bringing the specified
1188 C<$package_name> into existence and adding any of the C<$version>,
1189 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1192 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1193 methods =E<gt> ?%methods,
1194 attributes =E<gt> ?%attributes)>
1196 This will create an anonymous class, it works much like C<create> but
1197 it does not need a C<$package_name>. Instead it will create a suitably
1198 unique package name for you to stash things into.
1200 On very important distinction is that anon classes are destroyed once
1201 the metaclass they are attached to goes out of scope. In the DESTROY
1202 method, the created package will be removed from the symbol table.
1204 It is also worth noting that any instances created with an anon-class
1205 will keep a special reference to the anon-meta which will prevent the
1206 anon-class from going out of scope until all instances of it have also
1207 been destroyed. This however only works for HASH based instance types,
1208 as we use a special reserved slot (C<__MOP__>) to store this.
1210 =item B<initialize ($package_name, %options)>
1212 This initializes and returns returns a B<Class::MOP::Class> object for
1213 a given a C<$package_name>. If a metaclass already exists for the
1214 package, it simply returns it instead of creating a new one.
1216 =item B<construct_class_instance (%options)>
1218 This will construct an instance of B<Class::MOP::Class>, it is
1219 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1220 to use C<construct_instance> once all the bootstrapping is done. This
1221 method is used internally by C<initialize> and should never be called
1222 from outside of that method really.
1224 =item B<check_metaclass_compatibility>
1226 This method is called as the very last thing in the
1227 C<construct_class_instance> method. This will check that the
1228 metaclass you are creating is compatible with the metaclasses of all
1229 your ancestors. For more inforamtion about metaclass compatibility
1230 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1232 =item B<update_package_cache_flag>
1234 This will reset the package cache flag for this particular metaclass
1235 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1236 function. This is very rarely needed from outside of C<Class::MOP::Class>
1237 but in some cases you might want to use it, so it is here.
1239 =item B<reset_package_cache_flag>
1241 Clears the package cache flag to announce to the internals that we need
1242 to rebuild the method map.
1244 =item B<add_meta_instance_dependencies>
1246 Registers this class as dependent on its superclasses.
1248 Only superclasses from which this class inherits attributes will be added.
1250 =item B<remove_meta_instance_depdendencies>
1252 Unregisters this class from its superclasses.
1254 =item B<update_meta_instance_dependencies>
1256 Reregisters if necessary.
1258 =item B<add_dependent_meta_instance> $metaclass
1260 Registers the class as having a meta instance dependent on this class.
1262 =item B<remove_dependent_meta_instance> $metaclass
1264 Remove the class from the list of dependent classes.
1266 =item B<invalidate_meta_instances>
1268 Clears the cached meta instance for this metaclass and all of the registered
1269 classes with dependent meta instances.
1271 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1274 =item B<invalidate_meta_instance>
1276 Used by C<invalidate_meta_instances>.
1280 =head2 Object instance construction and cloning
1282 These methods are B<entirely optional>, it is up to you whether you want
1287 =item B<instance_metaclass>
1289 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1290 for more information on the instance metaclasses.
1292 =item B<get_meta_instance>
1294 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1295 of a new instance of the class.
1297 =item B<create_meta_instance>
1299 Called by C<get_meta_instance> if necessary.
1301 =item B<new_object (%params)>
1303 This is a convience method for creating a new object of the class, and
1304 blessing it into the appropriate package as well. Ideally your class
1305 would call a C<new> this method like so:
1308 my ($class, %param) = @_;
1309 $class->meta->new_object(%params);
1312 =item B<construct_instance (%params)>
1314 This method is used to construct an instance structure suitable for
1315 C<bless>-ing into your package of choice. It works in conjunction
1316 with the Attribute protocol to collect all applicable attributes.
1318 This will construct an instance using a HASH ref as storage
1319 (currently only HASH references are supported). This will collect all
1320 the applicable attributes and layout out the fields in the HASH ref,
1321 it will then initialize them using either use the corresponding key
1322 in C<%params> or any default value or initializer found in the
1323 attribute meta-object.
1325 =item B<clone_object ($instance, %params)>
1327 This is a convience method for cloning an object instance, then
1328 blessing it into the appropriate package. This method will call
1329 C<clone_instance>, which performs a shallow copy of the object,
1330 see that methods documentation for more details. Ideally your
1331 class would call a C<clone> this method like so:
1333 sub MyClass::clone {
1334 my ($self, %param) = @_;
1335 $self->meta->clone_object($self, %params);
1338 =item B<clone_instance($instance, %params)>
1340 This method is a compliment of C<construct_instance> (which means if
1341 you override C<construct_instance>, you need to override this one too),
1342 and clones the instance shallowly.
1344 The cloned structure returned is (like with C<construct_instance>) an
1345 unC<bless>ed HASH reference, it is your responsibility to then bless
1346 this cloned structure into the right class (which C<clone_object> will
1349 As of 0.11, this method will clone the C<$instance> structure shallowly,
1350 as opposed to the deep cloning implemented in prior versions. After much
1351 thought, research and discussion, I have decided that anything but basic
1352 shallow cloning is outside the scope of the meta-object protocol. I
1353 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1354 is too I<context-specific> to be part of the MOP.
1356 =item B<rebless_instance($instance, ?%params)>
1358 This will change the class of C<$instance> to the class of the invoking
1359 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1360 itself. You may pass in optional C<%params> which are like constructor
1361 params and will override anything already defined in the instance.
1365 =head2 Informational
1367 These are a few predicate methods for asking information about the class.
1371 =item B<is_anon_class>
1373 This returns true if the class is a C<Class::MOP::Class> created anon class.
1377 This returns true if the class is still mutable.
1379 =item B<is_immutable>
1381 This returns true if the class has been made immutable.
1383 =item B<is_pristine>
1385 Checks whether the class has any data that will be lost if C<reinitialize> is
1390 =head2 Inheritance Relationships
1394 =item B<superclasses (?@superclasses)>
1396 This is a read-write attribute which represents the superclass
1397 relationships of the class the B<Class::MOP::Class> instance is
1398 associated with. Basically, it can get and set the C<@ISA> for you.
1400 =item B<class_precedence_list>
1402 This computes the a list of all the class's ancestors in the same order
1403 in which method dispatch will be done. This is similair to what
1404 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1406 =item B<linearized_isa>
1408 This returns a list based on C<class_precedence_list> but with all
1413 This returns a list of subclasses for this class.
1421 =item B<get_method_map>
1423 Returns a HASH ref of name to L<Class::MOP::Method> instance mapping
1426 =item B<method_metaclass>
1428 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1429 for more information on the method metaclasses.
1431 =item B<wrap_method_body(%attrs)>
1433 Wrap a code ref (C<$attrs{body>) with C<method_metaclass>.
1435 =item B<add_method ($method_name, $method)>
1437 This will take a C<$method_name> and CODE reference or meta method
1438 objectand install it into the class's package.
1440 You are strongly encouraged to pass a meta method object instead of a
1441 code reference. If you do so, that object gets stored as part of the
1442 class's method map, providing more useful information about the method
1445 When you provide a method object, this method will clone that object
1446 if the object's package name does not match the class name. This lets
1447 us track the original source of any methods added from other classes
1448 (notably Moose roles).
1451 This does absolutely nothing special to C<$method>
1452 other than use B<Sub::Name> to make sure it is tagged with the
1453 correct name, and therefore show up correctly in stack traces and
1456 =item B<has_method ($method_name)>
1458 This just provides a simple way to check if the class implements
1459 a specific C<$method_name>. It will I<not> however, attempt to check
1460 if the class inherits the method (use C<UNIVERSAL::can> for that).
1462 This will correctly handle functions defined outside of the package
1463 that use a fully qualified name (C<sub Package::name { ... }>).
1465 This will correctly handle functions renamed with B<Sub::Name> and
1466 installed using the symbol tables. However, if you are naming the
1467 subroutine outside of the package scope, you must use the fully
1468 qualified name, including the package name, for C<has_method> to
1469 correctly identify it.
1471 This will attempt to correctly ignore functions imported from other
1472 packages using B<Exporter>. It breaks down if the function imported
1473 is an C<__ANON__> sub (such as with C<use constant>), which very well
1474 may be a valid method being applied to the class.
1476 In short, this method cannot always be trusted to determine if the
1477 C<$method_name> is actually a method. However, it will DWIM about
1478 90% of the time, so it's a small trade off I think.
1480 =item B<get_method ($method_name)>
1482 This will return a Class::MOP::Method instance related to the specified
1483 C<$method_name>, or return undef if that method does not exist.
1485 The Class::MOP::Method is codifiable, so you can use it like a normal
1486 CODE reference, see L<Class::MOP::Method> for more information.
1488 =item B<find_method_by_name ($method_name)>
1490 This will return a L<Class::MOP::Method> instance for the specified
1491 C<$method_name>, or return undef if that method does not exist.
1493 Unlike C<get_method> this will also look in the superclasses.
1495 =item B<remove_method ($method_name)>
1497 This will attempt to remove a given C<$method_name> from the class.
1498 It will return the L<Class::MOP::Method> instance that it has removed,
1499 and will attempt to use B<Sub::Name> to clear the methods associated
1502 =item B<get_method_list>
1504 This will return a list of method names for all I<locally> defined
1505 methods. It does B<not> provide a list of all applicable methods,
1506 including any inherited ones. If you want a list of all applicable
1507 methods, use the C<compute_all_applicable_methods> method.
1509 =item B<get_all_methods>
1511 This will traverse the inheritance hierarchy and return a list of all
1512 the applicable L<Class::MOP::Method> objects for this class.
1514 =item B<compute_all_applicable_methods>
1518 This method returns a list of hashes describing the all the methods of the
1521 Use L<get_all_methods>, which is easier/better/faster. This method predates
1522 L<Class::MOP::Method>.
1524 =item B<get_all_method_names>
1526 This will traverse the inheritance hierarchy and return a list of all the
1527 applicable method names for this class. Duplicate names are removed, but the
1528 order the methods come out is not defined.
1530 =item B<find_all_methods_by_name ($method_name)>
1532 This will traverse the inheritence hierarchy and locate all methods
1533 with a given C<$method_name>. Similar to
1534 C<compute_all_applicable_methods> it returns a list of HASH references
1535 with the following information; method name (which will always be the
1536 same as C<$method_name>), the name of the class in which the method
1537 lives and a CODE reference for the actual method.
1539 The list of methods produced is a distinct list, meaning there are no
1540 duplicates in it. This is especially useful for things like object
1541 initialization and destruction where you only want the method called
1542 once, and in the correct order.
1544 =item B<find_next_method_by_name ($method_name)>
1546 This will return the first method to match a given C<$method_name> in
1547 the superclasses, this is basically equivalent to calling
1548 C<SUPER::$method_name>, but it can be dispatched at runtime.
1550 =item B<alias_method ($method_name, $method)>
1552 B<NOTE>: This method is now deprecated. Just use C<add_method>
1557 =head2 Method Modifiers
1559 Method modifiers are a concept borrowed from CLOS, in which a method
1560 can be wrapped with I<before>, I<after> and I<around> method modifiers
1561 that will be called everytime the method is called.
1563 =head3 How method modifiers work?
1565 Method modifiers work by wrapping the original method and then replacing
1566 it in the classes symbol table. The wrappers will handle calling all the
1567 modifiers in the appropariate orders and preserving the calling context
1568 for the original method.
1570 Each method modifier serves a particular purpose, which may not be
1571 obvious to users of other method wrapping modules. To start with, the
1572 return values of I<before> and I<after> modifiers are ignored. This is
1573 because thier purpose is B<not> to filter the input and output of the
1574 primary method (this is done with an I<around> modifier). This may seem
1575 like an odd restriction to some, but doing this allows for simple code
1576 to be added at the begining or end of a method call without jeapordizing
1577 the normal functioning of the primary method or placing any extra
1578 responsibility on the code of the modifier. Of course if you have more
1579 complex needs, then use the I<around> modifier, which uses a variation
1580 of continutation passing style to allow for a high degree of flexibility.
1582 Before and around modifiers are called in last-defined-first-called order,
1583 while after modifiers are called in first-defined-first-called order. So
1584 the call tree might looks something like this:
1596 To see examples of using method modifiers, see the following examples
1597 included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
1598 F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
1599 classic CLOS usage example in the test F<017_add_method_modifier.t>.
1601 =head3 What is the performance impact?
1603 Of course there is a performance cost associated with method modifiers,
1604 but we have made every effort to make that cost be directly proportional
1605 to the amount of modifier features you utilize.
1607 The wrapping method does it's best to B<only> do as much work as it
1608 absolutely needs to. In order to do this we have moved some of the
1609 performance costs to set-up time, where they are easier to amortize.
1611 All this said, my benchmarks have indicated the following:
1613 simple wrapper with no modifiers 100% slower
1614 simple wrapper with simple before modifier 400% slower
1615 simple wrapper with simple after modifier 450% slower
1616 simple wrapper with simple around modifier 500-550% slower
1617 simple wrapper with all 3 modifiers 1100% slower
1619 These numbers may seem daunting, but you must remember, every feature
1620 comes with some cost. To put things in perspective, just doing a simple
1621 C<AUTOLOAD> which does nothing but extract the name of the method called
1622 and return it costs about 400% over a normal method call.
1626 =item B<add_before_method_modifier ($method_name, $code)>
1628 This will wrap the method at C<$method_name> and the supplied C<$code>
1629 will be passed the C<@_> arguments, and called before the original
1630 method is called. As specified above, the return value of the I<before>
1631 method modifiers is ignored, and it's ability to modify C<@_> is
1632 fairly limited. If you need to do either of these things, use an
1633 C<around> method modifier.
1635 =item B<add_after_method_modifier ($method_name, $code)>
1637 This will wrap the method at C<$method_name> so that the original
1638 method will be called, it's return values stashed, and then the
1639 supplied C<$code> will be passed the C<@_> arguments, and called.
1640 As specified above, the return value of the I<after> method
1641 modifiers is ignored, and it cannot modify the return values of
1642 the original method. If you need to do either of these things, use an
1643 C<around> method modifier.
1645 =item B<add_around_method_modifier ($method_name, $code)>
1647 This will wrap the method at C<$method_name> so that C<$code>
1648 will be called and passed the original method as an extra argument
1649 at the begining of the C<@_> argument list. This is a variation of
1650 continuation passing style, where the function prepended to C<@_>
1651 can be considered a continuation. It is up to C<$code> if it calls
1652 the original method or not, there is no restriction on what the
1653 C<$code> can or cannot do.
1659 It should be noted that since there is no one consistent way to define
1660 the attributes of a class in Perl 5. These methods can only work with
1661 the information given, and can not easily discover information on
1662 their own. See L<Class::MOP::Attribute> for more details.
1666 =item B<attribute_metaclass>
1668 Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute>
1669 for more information on the attribute metaclasses.
1671 =item B<get_attribute_map>
1673 This returns a HASH ref of name to attribute meta-object mapping.
1675 =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))>
1677 This stores the C<$attribute_meta_object> (or creates one from the
1678 C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class>
1679 instance associated with the given class. Unlike methods, attributes
1680 within the MOP are stored as meta-information only. They will be used
1681 later to construct instances from (see C<construct_instance> above).
1682 More details about the attribute meta-objects can be found in the
1683 L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol>
1686 It should be noted that any accessor, reader/writer or predicate
1687 methods which the C<$attribute_meta_object> has will be installed
1688 into the class at this time.
1691 If an attribute already exists for C<$attribute_name>, the old one
1692 will be removed (as well as removing all it's accessors), and then
1695 =item B<has_attribute ($attribute_name)>
1697 Checks to see if this class has an attribute by the name of
1698 C<$attribute_name> and returns a boolean.
1700 =item B<get_attribute ($attribute_name)>
1702 Returns the attribute meta-object associated with C<$attribute_name>,
1703 if none is found, it will return undef.
1705 =item B<remove_attribute ($attribute_name)>
1707 This will remove the attribute meta-object stored at
1708 C<$attribute_name>, then return the removed attribute meta-object.
1711 Removing an attribute will only affect future instances of
1712 the class, it will not make any attempt to remove the attribute from
1713 any existing instances of the class.
1715 It should be noted that any accessor, reader/writer or predicate
1716 methods which the attribute meta-object stored at C<$attribute_name>
1717 has will be removed from the class at this time. This B<will> make
1718 these attributes somewhat inaccessable in previously created
1719 instances. But if you are crazy enough to do this at runtime, then
1720 you are crazy enough to deal with something like this :).
1722 =item B<get_attribute_list>
1724 This returns a list of attribute names which are defined in the local
1725 class. If you want a list of all applicable attributes for a class,
1726 use the C<compute_all_applicable_attributes> method.
1728 =item B<compute_all_applicable_attributes>
1730 =item B<get_all_attributes>
1732 This will traverse the inheritance hierarchy and return a list of all
1733 the applicable L<Class::MOP::Attribute> objects for this class.
1735 C<get_all_attributes> is an alias for consistency with C<get_all_methods>.
1737 =item B<find_attribute_by_name ($attr_name)>
1739 This method will traverse the inheritance hierarchy and find the
1740 first attribute whose name matches C<$attr_name>, then return it.
1741 It will return undef if nothing is found.
1745 =head2 Class Immutability
1749 =item B<make_immutable (%options)>
1751 This method will invoke a tranforamtion upon the class which will
1752 make it immutable. Details of this transformation can be found in
1753 the L<Class::MOP::Immutable> documentation.
1755 =item B<make_mutable>
1757 This method will reverse tranforamtion upon the class which
1760 =item B<get_immutable_transformer>
1762 Return a transformer suitable for making this class immutable or, if this
1763 class is immutable, the transformer used to make it immutable.
1765 =item B<get_immutable_options>
1767 If the class is immutable, return the options used to make it immutable.
1769 =item B<create_immutable_transformer>
1771 Create a transformer suitable for making this class immutable
1777 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1779 =head1 COPYRIGHT AND LICENSE
1781 Copyright 2006-2008 by Infinity Interactive, Inc.
1783 L<http://www.iinteractive.com>
1785 This library is free software; you can redistribute it and/or modify
1786 it under the same terms as Perl itself.