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 = '0.78';
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 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
431 $meta_instance->rebless_instance_structure($_[1], $self);
433 foreach my $attr ( $self->compute_all_applicable_attributes ) {
434 if ( $attr->has_value($instance) ) {
435 if ( defined( my $init_arg = $attr->init_arg ) ) {
436 $params{$init_arg} = $attr->get_value($instance)
437 unless exists $params{$init_arg};
440 $attr->set_value($instance, $attr->get_value($instance));
445 foreach my $attr ($self->compute_all_applicable_attributes) {
446 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
456 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
459 @{$self->get_package_symbol($var_spec)} = @supers;
462 # on 5.8 and below, we need to call
463 # a method to get Perl to detect
464 # a cycle in the class hierarchy
465 my $class = $self->name;
469 # we need to check the metaclass
470 # compatibility here so that we can
471 # be sure that the superclass is
472 # not potentially creating an issues
473 # we don't know about
475 $self->check_metaclass_compatibility();
476 $self->update_meta_instance_dependencies();
478 @{$self->get_package_symbol($var_spec)};
484 my $super_class = $self->name;
486 if ( Class::MOP::HAVE_ISAREV() ) {
487 return @{ $super_class->mro::get_isarev() };
491 my $find_derived_classes;
492 $find_derived_classes = sub {
493 my ($outer_class) = @_;
495 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
498 for my $symbol ( keys %$symbol_table_hashref ) {
499 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
500 my $inner_class = $1;
502 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
506 ? "${outer_class}::$inner_class"
509 if ( $class->isa($super_class) and $class ne $super_class ) {
510 push @derived_classes, $class;
513 next SYMBOL if $class eq 'main'; # skip 'main::*'
515 $find_derived_classes->($class);
519 my $root_class = q{};
520 $find_derived_classes->($root_class);
522 undef $find_derived_classes;
524 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
526 return @derived_classes;
532 return @{ mro::get_linear_isa( (shift)->name ) };
535 sub class_precedence_list {
537 my $name = $self->name;
539 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
541 # We need to check for circular inheritance here
542 # if we are are not on 5.10, cause 5.8 detects it
543 # late. This will do nothing if all is well, and
544 # blow up otherwise. Yes, it's an ugly hack, better
545 # suggestions are welcome.
547 ($name || return)->isa('This is a test for circular inheritance')
550 # if our mro is c3, we can
551 # just grab the linear_isa
552 if (mro::get_mro($name) eq 'c3') {
553 return @{ mro::get_linear_isa($name) }
557 # we can't grab the linear_isa for dfs
558 # since it has all the duplicates
563 $self->initialize($_)->class_precedence_list()
564 } $self->superclasses()
571 sub wrap_method_body {
572 my ( $self, %args ) = @_;
574 ('CODE' eq ref $args{body})
575 || confess "Your code block must be a CODE reference";
577 $self->method_metaclass->wrap(
578 package_name => $self->name,
584 my ($self, $method_name, $method) = @_;
585 (defined $method_name && $method_name)
586 || confess "You must define a method name";
589 if (blessed($method)) {
590 $body = $method->body;
591 if ($method->package_name ne $self->name) {
592 $method = $method->clone(
593 package_name => $self->name,
595 ) if $method->can('clone');
600 $method = $self->wrap_method_body( body => $body, name => $method_name );
603 $method->attach_to_class($self);
605 # This used to call get_method_map, which meant we would build all
606 # the method objects for the class just because we added one
607 # method. This is hackier, but quicker too.
608 $self->{methods}{$method_name} = $method;
610 my $full_method_name = ($self->name . '::' . $method_name);
611 $self->add_package_symbol(
612 { sigil => '&', type => 'CODE', name => $method_name },
613 Class::MOP::subname($full_method_name => $body)
618 my $fetch_and_prepare_method = sub {
619 my ($self, $method_name) = @_;
620 my $wrapped_metaclass = $self->wrapped_method_metaclass;
622 my $method = $self->get_method($method_name);
623 # if we dont have local ...
625 # try to find the next method
626 $method = $self->find_next_method_by_name($method_name);
627 # die if it does not exist
629 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
630 # and now make sure to wrap it
631 # even if it is already wrapped
632 # because we need a new sub ref
633 $method = $wrapped_metaclass->wrap($method);
636 # now make sure we wrap it properly
637 $method = $wrapped_metaclass->wrap($method)
638 unless $method->isa($wrapped_metaclass);
640 $self->add_method($method_name => $method);
644 sub add_before_method_modifier {
645 my ($self, $method_name, $method_modifier) = @_;
646 (defined $method_name && $method_name)
647 || confess "You must pass in a method name";
648 my $method = $fetch_and_prepare_method->($self, $method_name);
649 $method->add_before_modifier(
650 Class::MOP::subname(':before' => $method_modifier)
654 sub add_after_method_modifier {
655 my ($self, $method_name, $method_modifier) = @_;
656 (defined $method_name && $method_name)
657 || confess "You must pass in a method name";
658 my $method = $fetch_and_prepare_method->($self, $method_name);
659 $method->add_after_modifier(
660 Class::MOP::subname(':after' => $method_modifier)
664 sub add_around_method_modifier {
665 my ($self, $method_name, $method_modifier) = @_;
666 (defined $method_name && $method_name)
667 || confess "You must pass in a method name";
668 my $method = $fetch_and_prepare_method->($self, $method_name);
669 $method->add_around_modifier(
670 Class::MOP::subname(':around' => $method_modifier)
675 # the methods above used to be named like this:
676 # ${pkg}::${method}:(before|after|around)
677 # but this proved problematic when using one modifier
678 # to wrap multiple methods (something which is likely
679 # to happen pretty regularly IMO). So instead of naming
680 # it like this, I have chosen to just name them purely
681 # with their modifier names, like so:
682 # :(before|after|around)
683 # The fact is that in a stack trace, it will be fairly
684 # evident from the context what method they are attached
685 # to, and so don't need the fully qualified name.
691 $self->add_method(@_);
695 my ($self, $method_name) = @_;
696 (defined $method_name && $method_name)
697 || confess "You must define a method name";
699 exists $self->{methods}{$method_name} || exists $self->get_method_map->{$method_name};
703 my ($self, $method_name) = @_;
704 (defined $method_name && $method_name)
705 || confess "You must define a method name";
707 return $self->{methods}{$method_name} || $self->get_method_map->{$method_name};
711 my ($self, $method_name) = @_;
712 (defined $method_name && $method_name)
713 || confess "You must define a method name";
715 my $removed_method = delete $self->get_method_map->{$method_name};
717 $self->remove_package_symbol(
718 { sigil => '&', type => 'CODE', name => $method_name }
721 $removed_method->detach_from_class if $removed_method;
723 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
725 return $removed_method;
728 sub get_method_list {
730 keys %{$self->get_method_map};
733 sub find_method_by_name {
734 my ($self, $method_name) = @_;
735 (defined $method_name && $method_name)
736 || confess "You must define a method name to find";
737 foreach my $class ($self->linearized_isa) {
738 # fetch the meta-class ...
739 my $meta = $self->initialize($class);
740 return $meta->get_method($method_name)
741 if $meta->has_method($method_name);
746 sub get_all_methods {
748 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
749 return values %methods;
753 sub compute_all_applicable_methods {
757 class => $_->package_name,
758 code => $_, # sigh, overloading
760 } shift->get_all_methods(@_);
763 sub get_all_method_names {
766 grep { $uniq{$_}++ == 0 } map { $_->name } $self->get_all_methods;
769 sub find_all_methods_by_name {
770 my ($self, $method_name) = @_;
771 (defined $method_name && $method_name)
772 || confess "You must define a method name to find";
774 foreach my $class ($self->linearized_isa) {
775 # fetch the meta-class ...
776 my $meta = $self->initialize($class);
778 name => $method_name,
780 code => $meta->get_method($method_name)
781 } if $meta->has_method($method_name);
786 sub find_next_method_by_name {
787 my ($self, $method_name) = @_;
788 (defined $method_name && $method_name)
789 || confess "You must define a method name to find";
790 my @cpl = $self->linearized_isa;
791 shift @cpl; # discard ourselves
792 foreach my $class (@cpl) {
793 # fetch the meta-class ...
794 my $meta = $self->initialize($class);
795 return $meta->get_method($method_name)
796 if $meta->has_method($method_name);
805 # either we have an attribute object already
806 # or we need to create one from the args provided
807 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
808 # make sure it is derived from the correct type though
809 ($attribute->isa('Class::MOP::Attribute'))
810 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
812 # first we attach our new attribute
813 # because it might need certain information
814 # about the class which it is attached to
815 $attribute->attach_to_class($self);
817 # then we remove attributes of a conflicting
818 # name here so that we can properly detach
819 # the old attr object, and remove any
820 # accessors it would have generated
821 if ( $self->has_attribute($attribute->name) ) {
822 $self->remove_attribute($attribute->name);
824 $self->invalidate_meta_instances();
827 # then onto installing the new accessors
828 $self->get_attribute_map->{$attribute->name} = $attribute;
830 # invalidate package flag here
831 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
833 $self->remove_attribute($attribute->name);
840 sub update_meta_instance_dependencies {
843 if ( $self->{meta_instance_dependencies} ) {
844 return $self->add_meta_instance_dependencies;
848 sub add_meta_instance_dependencies {
851 $self->remove_meta_instance_depdendencies;
853 my @attrs = $self->compute_all_applicable_attributes();
856 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
858 foreach my $class ( @classes ) {
859 $class->add_dependent_meta_instance($self);
862 $self->{meta_instance_dependencies} = \@classes;
865 sub remove_meta_instance_depdendencies {
868 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
869 foreach my $class ( @$classes ) {
870 $class->remove_dependent_meta_instance($self);
880 sub add_dependent_meta_instance {
881 my ( $self, $metaclass ) = @_;
882 push @{ $self->{dependent_meta_instances} }, $metaclass;
885 sub remove_dependent_meta_instance {
886 my ( $self, $metaclass ) = @_;
887 my $name = $metaclass->name;
888 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
891 sub invalidate_meta_instances {
893 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
896 sub invalidate_meta_instance {
898 undef $self->{_meta_instance};
902 my ($self, $attribute_name) = @_;
903 (defined $attribute_name && $attribute_name)
904 || confess "You must define an attribute name";
905 exists $self->get_attribute_map->{$attribute_name};
909 my ($self, $attribute_name) = @_;
910 (defined $attribute_name && $attribute_name)
911 || confess "You must define an attribute name";
912 return $self->get_attribute_map->{$attribute_name}
914 # this will return undef anyway, so no need ...
915 # if $self->has_attribute($attribute_name);
919 sub remove_attribute {
920 my ($self, $attribute_name) = @_;
921 (defined $attribute_name && $attribute_name)
922 || confess "You must define an attribute name";
923 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
924 return unless defined $removed_attribute;
925 delete $self->get_attribute_map->{$attribute_name};
926 $self->invalidate_meta_instances();
927 $removed_attribute->remove_accessors();
928 $removed_attribute->detach_from_class();
929 return $removed_attribute;
932 sub get_attribute_list {
934 keys %{$self->get_attribute_map};
937 sub get_all_attributes {
938 shift->compute_all_applicable_attributes(@_);
941 sub compute_all_applicable_attributes {
943 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
944 return values %attrs;
947 sub find_attribute_by_name {
948 my ($self, $attr_name) = @_;
949 foreach my $class ($self->linearized_isa) {
950 # fetch the meta-class ...
951 my $meta = $self->initialize($class);
952 return $meta->get_attribute($attr_name)
953 if $meta->has_attribute($attr_name);
958 # check if we can reinitialize
962 # if any local attr is defined
963 return if $self->get_attribute_list;
965 # or any non-declared methods
966 if ( my @methods = values %{ $self->get_method_map } ) {
967 my $metaclass = $self->method_metaclass;
968 foreach my $method ( @methods ) {
969 return if $method->isa("Class::MOP::Method::Generated");
970 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
980 sub is_immutable { 0 }
983 # Why I changed this (groditi)
984 # - One Metaclass may have many Classes through many Metaclass instances
985 # - One Metaclass should only have one Immutable Transformer instance
986 # - Each Class may have different Immutabilizing options
987 # - Therefore each Metaclass instance may have different Immutabilizing options
988 # - We need to store one Immutable Transformer instance per Metaclass
989 # - We need to store one set of Immutable Transformer options per Class
990 # - Upon make_mutable we may delete the Immutabilizing options
991 # - We could clean the immutable Transformer instance when there is no more
992 # immutable Classes of that type, but we can also keep it in case
993 # another class with this same Metaclass becomes immutable. It is a case
994 # of trading of storing an instance to avoid unnecessary instantiations of
995 # Immutable Transformers. You may view this as a memory leak, however
996 # Because we have few Metaclasses, in practice it seems acceptable
997 # - To allow Immutable Transformers instances to be cleaned up we could weaken
998 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
1002 my %IMMUTABLE_TRANSFORMERS;
1003 my %IMMUTABLE_OPTIONS;
1005 sub get_immutable_options {
1007 return if $self->is_mutable;
1008 confess "unable to find immutabilizing options"
1009 unless exists $IMMUTABLE_OPTIONS{$self->name};
1010 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1011 delete $options{IMMUTABLE_TRANSFORMER};
1015 sub get_immutable_transformer {
1017 if( $self->is_mutable ){
1018 return $IMMUTABLE_TRANSFORMERS{$self->name} ||= $self->create_immutable_transformer;
1020 confess "unable to find transformer for immutable class"
1021 unless exists $IMMUTABLE_OPTIONS{$self->name};
1022 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1025 sub make_immutable {
1029 my $transformer = $self->get_immutable_transformer;
1030 $transformer->make_metaclass_immutable($self, \%options);
1031 $IMMUTABLE_OPTIONS{$self->name} =
1032 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1034 if( exists $options{debug} && $options{debug} ){
1035 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1036 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1044 return if $self->is_mutable;
1045 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1046 confess "unable to find immutabilizing options" unless ref $options;
1047 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1048 $transformer->make_metaclass_mutable($self, $options);
1053 sub create_immutable_transformer {
1055 my $class = Class::MOP::Immutable->new($self, {
1056 read_only => [qw/superclasses/],
1063 remove_package_symbol
1066 class_precedence_list => 'ARRAY',
1067 linearized_isa => 'ARRAY', # FIXME perl 5.10 memoizes this on its own, no need?
1068 get_all_methods => 'ARRAY',
1069 get_all_method_names => 'ARRAY',
1070 #get_all_attributes => 'ARRAY', # it's an alias, no need, but maybe in the future
1071 compute_all_applicable_attributes => 'ARRAY',
1072 get_meta_instance => 'SCALAR',
1073 get_method_map => 'SCALAR',
1076 # this is ugly, but so are typeglobs,
1077 # so whattayahgonnadoboutit
1080 add_package_symbol => sub {
1081 my $original = shift;
1082 confess "Cannot add package symbols to an immutable metaclass"
1083 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1085 # This is a workaround for a bug in 5.8.1 which thinks that
1086 # goto $original->body
1087 # is trying to go to a label
1088 my $body = $original->body;
1104 Class::MOP::Class - Class Meta Object
1108 # assuming that class Foo
1109 # has been defined, you can
1111 # use this for introspection ...
1113 # add a method to Foo ...
1114 Foo->meta->add_method('bar' => sub { ... })
1116 # get a list of all the classes searched
1117 # the method dispatcher in the correct order
1118 Foo->meta->class_precedence_list()
1120 # remove a method from Foo
1121 Foo->meta->remove_method('bar');
1123 # or use this to actually create classes ...
1125 Class::MOP::Class->create('Bar' => (
1127 superclasses => [ 'Foo' ],
1129 Class::MOP:::Attribute->new('$bar'),
1130 Class::MOP:::Attribute->new('$baz'),
1133 calculate_bar => sub { ... },
1134 construct_baz => sub { ... }
1140 This is the largest and currently most complex part of the Perl 5
1141 meta-object protocol. It controls the introspection and
1142 manipulation of Perl 5 classes (and it can create them too). The
1143 best way to understand what this module can do, is to read the
1144 documentation for each of it's methods.
1148 B<Class::MOP::Class> is a subclass of L<Class::MOP::Module>
1152 =head2 Self Introspection
1158 This will return a B<Class::MOP::Class> instance which is related
1159 to this class. Thereby allowing B<Class::MOP::Class> to actually
1162 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1163 bootstrap this module by installing a number of attribute meta-objects
1164 into it's metaclass. This will allow this class to reap all the benifits
1165 of the MOP when subclassing it.
1169 =head2 Class construction
1171 These methods will handle creating B<Class::MOP::Class> objects,
1172 which can be used to both create new classes, and analyze
1173 pre-existing classes.
1175 This module will internally store references to all the instances
1176 you create with these methods, so that they do not need to be
1177 created any more than nessecary. Basically, they are singletons.
1181 =item B<create ($package_name,
1182 version =E<gt> ?$version,
1183 authority =E<gt> ?$authority,
1184 superclasses =E<gt> ?@superclasses,
1185 methods =E<gt> ?%methods,
1186 attributes =E<gt> ?%attributes)>
1188 This returns a B<Class::MOP::Class> object, bringing the specified
1189 C<$package_name> into existence and adding any of the C<$version>,
1190 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1193 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1194 methods =E<gt> ?%methods,
1195 attributes =E<gt> ?%attributes)>
1197 This will create an anonymous class, it works much like C<create> but
1198 it does not need a C<$package_name>. Instead it will create a suitably
1199 unique package name for you to stash things into.
1201 On very important distinction is that anon classes are destroyed once
1202 the metaclass they are attached to goes out of scope. In the DESTROY
1203 method, the created package will be removed from the symbol table.
1205 It is also worth noting that any instances created with an anon-class
1206 will keep a special reference to the anon-meta which will prevent the
1207 anon-class from going out of scope until all instances of it have also
1208 been destroyed. This however only works for HASH based instance types,
1209 as we use a special reserved slot (C<__MOP__>) to store this.
1211 =item B<initialize ($package_name, %options)>
1213 This initializes and returns returns a B<Class::MOP::Class> object for
1214 a given a C<$package_name>. If a metaclass already exists for the
1215 package, it simply returns it instead of creating a new one.
1217 =item B<construct_class_instance (%options)>
1219 This will construct an instance of B<Class::MOP::Class>, it is
1220 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1221 to use C<construct_instance> once all the bootstrapping is done. This
1222 method is used internally by C<initialize> and should never be called
1223 from outside of that method really.
1225 =item B<check_metaclass_compatibility>
1227 This method is called as the very last thing in the
1228 C<construct_class_instance> method. This will check that the
1229 metaclass you are creating is compatible with the metaclasses of all
1230 your ancestors. For more inforamtion about metaclass compatibility
1231 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1233 =item B<update_package_cache_flag>
1235 This will reset the package cache flag for this particular metaclass
1236 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1237 function. This is very rarely needed from outside of C<Class::MOP::Class>
1238 but in some cases you might want to use it, so it is here.
1240 =item B<reset_package_cache_flag>
1242 Clears the package cache flag to announce to the internals that we need
1243 to rebuild the method map.
1245 =item B<add_meta_instance_dependencies>
1247 Registers this class as dependent on its superclasses.
1249 Only superclasses from which this class inherits attributes will be added.
1251 =item B<remove_meta_instance_depdendencies>
1253 Unregisters this class from its superclasses.
1255 =item B<update_meta_instance_dependencies>
1257 Reregisters if necessary.
1259 =item B<add_dependent_meta_instance> $metaclass
1261 Registers the class as having a meta instance dependent on this class.
1263 =item B<remove_dependent_meta_instance> $metaclass
1265 Remove the class from the list of dependent classes.
1267 =item B<invalidate_meta_instances>
1269 Clears the cached meta instance for this metaclass and all of the registered
1270 classes with dependent meta instances.
1272 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1275 =item B<invalidate_meta_instance>
1277 Used by C<invalidate_meta_instances>.
1281 =head2 Object instance construction and cloning
1283 These methods are B<entirely optional>, it is up to you whether you want
1288 =item B<instance_metaclass>
1290 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1291 for more information on the instance metaclasses.
1293 =item B<get_meta_instance>
1295 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1296 of a new instance of the class.
1298 =item B<create_meta_instance>
1300 Called by C<get_meta_instance> if necessary.
1302 =item B<new_object (%params)>
1304 This is a convience method for creating a new object of the class, and
1305 blessing it into the appropriate package as well. Ideally your class
1306 would call a C<new> this method like so:
1309 my ($class, %param) = @_;
1310 $class->meta->new_object(%params);
1313 =item B<construct_instance (%params)>
1315 This method is used to construct an instance structure suitable for
1316 C<bless>-ing into your package of choice. It works in conjunction
1317 with the Attribute protocol to collect all applicable attributes.
1319 This will construct an instance using a HASH ref as storage
1320 (currently only HASH references are supported). This will collect all
1321 the applicable attributes and layout out the fields in the HASH ref,
1322 it will then initialize them using either use the corresponding key
1323 in C<%params> or any default value or initializer found in the
1324 attribute meta-object.
1326 =item B<clone_object ($instance, %params)>
1328 This is a convience method for cloning an object instance, then
1329 blessing it into the appropriate package. This method will call
1330 C<clone_instance>, which performs a shallow copy of the object,
1331 see that methods documentation for more details. Ideally your
1332 class would call a C<clone> this method like so:
1334 sub MyClass::clone {
1335 my ($self, %param) = @_;
1336 $self->meta->clone_object($self, %params);
1339 =item B<clone_instance($instance, %params)>
1341 This method is a compliment of C<construct_instance> (which means if
1342 you override C<construct_instance>, you need to override this one too),
1343 and clones the instance shallowly.
1345 The cloned structure returned is (like with C<construct_instance>) an
1346 unC<bless>ed HASH reference, it is your responsibility to then bless
1347 this cloned structure into the right class (which C<clone_object> will
1350 As of 0.11, this method will clone the C<$instance> structure shallowly,
1351 as opposed to the deep cloning implemented in prior versions. After much
1352 thought, research and discussion, I have decided that anything but basic
1353 shallow cloning is outside the scope of the meta-object protocol. I
1354 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1355 is too I<context-specific> to be part of the MOP.
1357 =item B<rebless_instance($instance, ?%params)>
1359 This will change the class of C<$instance> to the class of the invoking
1360 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1361 itself. You may pass in optional C<%params> which are like constructor
1362 params and will override anything already defined in the instance.
1366 =head2 Informational
1368 These are a few predicate methods for asking information about the class.
1372 =item B<is_anon_class>
1374 This returns true if the class is a C<Class::MOP::Class> created anon class.
1378 This returns true if the class is still mutable.
1380 =item B<is_immutable>
1382 This returns true if the class has been made immutable.
1384 =item B<is_pristine>
1386 Checks whether the class has any data that will be lost if C<reinitialize> is
1391 =head2 Inheritance Relationships
1395 =item B<superclasses (?@superclasses)>
1397 This is a read-write attribute which represents the superclass
1398 relationships of the class the B<Class::MOP::Class> instance is
1399 associated with. Basically, it can get and set the C<@ISA> for you.
1401 =item B<class_precedence_list>
1403 This computes the a list of all the class's ancestors in the same order
1404 in which method dispatch will be done. This is similair to what
1405 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1407 =item B<linearized_isa>
1409 This returns a list based on C<class_precedence_list> but with all
1414 This returns a list of subclasses for this class.
1422 =item B<get_method_map>
1424 Returns a HASH ref of name to L<Class::MOP::Method> instance mapping
1427 =item B<method_metaclass>
1429 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1430 for more information on the method metaclasses.
1432 =item B<wrap_method_body(%attrs)>
1434 Wrap a code ref (C<$attrs{body>) with C<method_metaclass>.
1436 =item B<add_method ($method_name, $method)>
1438 This will take a C<$method_name> and CODE reference or meta method
1439 objectand install it into the class's package.
1441 You are strongly encouraged to pass a meta method object instead of a
1442 code reference. If you do so, that object gets stored as part of the
1443 class's method map, providing more useful information about the method
1446 When you provide a method object, this method will clone that object
1447 if the object's package name does not match the class name. This lets
1448 us track the original source of any methods added from other classes
1449 (notably Moose roles).
1452 This does absolutely nothing special to C<$method>
1453 other than use B<Sub::Name> to make sure it is tagged with the
1454 correct name, and therefore show up correctly in stack traces and
1457 =item B<has_method ($method_name)>
1459 This just provides a simple way to check if the class implements
1460 a specific C<$method_name>. It will I<not> however, attempt to check
1461 if the class inherits the method (use C<UNIVERSAL::can> for that).
1463 This will correctly handle functions defined outside of the package
1464 that use a fully qualified name (C<sub Package::name { ... }>).
1466 This will correctly handle functions renamed with B<Sub::Name> and
1467 installed using the symbol tables. However, if you are naming the
1468 subroutine outside of the package scope, you must use the fully
1469 qualified name, including the package name, for C<has_method> to
1470 correctly identify it.
1472 This will attempt to correctly ignore functions imported from other
1473 packages using B<Exporter>. It breaks down if the function imported
1474 is an C<__ANON__> sub (such as with C<use constant>), which very well
1475 may be a valid method being applied to the class.
1477 In short, this method cannot always be trusted to determine if the
1478 C<$method_name> is actually a method. However, it will DWIM about
1479 90% of the time, so it's a small trade off I think.
1481 =item B<get_method ($method_name)>
1483 This will return a Class::MOP::Method instance related to the specified
1484 C<$method_name>, or return undef if that method does not exist.
1486 The Class::MOP::Method is codifiable, so you can use it like a normal
1487 CODE reference, see L<Class::MOP::Method> for more information.
1489 =item B<find_method_by_name ($method_name)>
1491 This will return a L<Class::MOP::Method> instance for the specified
1492 C<$method_name>, or return undef if that method does not exist.
1494 Unlike C<get_method> this will also look in the superclasses.
1496 =item B<remove_method ($method_name)>
1498 This will attempt to remove a given C<$method_name> from the class.
1499 It will return the L<Class::MOP::Method> instance that it has removed,
1500 and will attempt to use B<Sub::Name> to clear the methods associated
1503 =item B<get_method_list>
1505 This will return a list of method names for all I<locally> defined
1506 methods. It does B<not> provide a list of all applicable methods,
1507 including any inherited ones. If you want a list of all applicable
1508 methods, use the C<compute_all_applicable_methods> method.
1510 =item B<get_all_methods>
1512 This will traverse the inheritance hierarchy and return a list of all
1513 the applicable L<Class::MOP::Method> objects for this class.
1515 =item B<compute_all_applicable_methods>
1519 This method returns a list of hashes describing the all the methods of the
1522 Use L<get_all_methods>, which is easier/better/faster. This method predates
1523 L<Class::MOP::Method>.
1525 =item B<get_all_method_names>
1527 This will traverse the inheritance hierarchy and return a list of all the
1528 applicable method names for this class. Duplicate names are removed, but the
1529 order the methods come out is not defined.
1531 =item B<find_all_methods_by_name ($method_name)>
1533 This will traverse the inheritence hierarchy and locate all methods
1534 with a given C<$method_name>. Similar to
1535 C<compute_all_applicable_methods> it returns a list of HASH references
1536 with the following information; method name (which will always be the
1537 same as C<$method_name>), the name of the class in which the method
1538 lives and a CODE reference for the actual method.
1540 The list of methods produced is a distinct list, meaning there are no
1541 duplicates in it. This is especially useful for things like object
1542 initialization and destruction where you only want the method called
1543 once, and in the correct order.
1545 =item B<find_next_method_by_name ($method_name)>
1547 This will return the first method to match a given C<$method_name> in
1548 the superclasses, this is basically equivalent to calling
1549 C<SUPER::$method_name>, but it can be dispatched at runtime.
1551 =item B<alias_method ($method_name, $method)>
1553 B<NOTE>: This method is now deprecated. Just use C<add_method>
1558 =head2 Method Modifiers
1560 Method modifiers are a concept borrowed from CLOS, in which a method
1561 can be wrapped with I<before>, I<after> and I<around> method modifiers
1562 that will be called everytime the method is called.
1564 =head3 How method modifiers work?
1566 Method modifiers work by wrapping the original method and then replacing
1567 it in the classes symbol table. The wrappers will handle calling all the
1568 modifiers in the appropariate orders and preserving the calling context
1569 for the original method.
1571 Each method modifier serves a particular purpose, which may not be
1572 obvious to users of other method wrapping modules. To start with, the
1573 return values of I<before> and I<after> modifiers are ignored. This is
1574 because thier purpose is B<not> to filter the input and output of the
1575 primary method (this is done with an I<around> modifier). This may seem
1576 like an odd restriction to some, but doing this allows for simple code
1577 to be added at the begining or end of a method call without jeapordizing
1578 the normal functioning of the primary method or placing any extra
1579 responsibility on the code of the modifier. Of course if you have more
1580 complex needs, then use the I<around> modifier, which uses a variation
1581 of continutation passing style to allow for a high degree of flexibility.
1583 Before and around modifiers are called in last-defined-first-called order,
1584 while after modifiers are called in first-defined-first-called order. So
1585 the call tree might looks something like this:
1597 To see examples of using method modifiers, see the following examples
1598 included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
1599 F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
1600 classic CLOS usage example in the test F<017_add_method_modifier.t>.
1602 =head3 What is the performance impact?
1604 Of course there is a performance cost associated with method modifiers,
1605 but we have made every effort to make that cost be directly proportional
1606 to the amount of modifier features you utilize.
1608 The wrapping method does it's best to B<only> do as much work as it
1609 absolutely needs to. In order to do this we have moved some of the
1610 performance costs to set-up time, where they are easier to amortize.
1612 All this said, my benchmarks have indicated the following:
1614 simple wrapper with no modifiers 100% slower
1615 simple wrapper with simple before modifier 400% slower
1616 simple wrapper with simple after modifier 450% slower
1617 simple wrapper with simple around modifier 500-550% slower
1618 simple wrapper with all 3 modifiers 1100% slower
1620 These numbers may seem daunting, but you must remember, every feature
1621 comes with some cost. To put things in perspective, just doing a simple
1622 C<AUTOLOAD> which does nothing but extract the name of the method called
1623 and return it costs about 400% over a normal method call.
1627 =item B<add_before_method_modifier ($method_name, $code)>
1629 This will wrap the method at C<$method_name> and the supplied C<$code>
1630 will be passed the C<@_> arguments, and called before the original
1631 method is called. As specified above, the return value of the I<before>
1632 method modifiers is ignored, and it's ability to modify C<@_> is
1633 fairly limited. If you need to do either of these things, use an
1634 C<around> method modifier.
1636 =item B<add_after_method_modifier ($method_name, $code)>
1638 This will wrap the method at C<$method_name> so that the original
1639 method will be called, it's return values stashed, and then the
1640 supplied C<$code> will be passed the C<@_> arguments, and called.
1641 As specified above, the return value of the I<after> method
1642 modifiers is ignored, and it cannot modify the return values of
1643 the original method. If you need to do either of these things, use an
1644 C<around> method modifier.
1646 =item B<add_around_method_modifier ($method_name, $code)>
1648 This will wrap the method at C<$method_name> so that C<$code>
1649 will be called and passed the original method as an extra argument
1650 at the begining of the C<@_> argument list. This is a variation of
1651 continuation passing style, where the function prepended to C<@_>
1652 can be considered a continuation. It is up to C<$code> if it calls
1653 the original method or not, there is no restriction on what the
1654 C<$code> can or cannot do.
1660 It should be noted that since there is no one consistent way to define
1661 the attributes of a class in Perl 5. These methods can only work with
1662 the information given, and can not easily discover information on
1663 their own. See L<Class::MOP::Attribute> for more details.
1667 =item B<attribute_metaclass>
1669 Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute>
1670 for more information on the attribute metaclasses.
1672 =item B<get_attribute_map>
1674 This returns a HASH ref of name to attribute meta-object mapping.
1676 =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))>
1678 This stores the C<$attribute_meta_object> (or creates one from the
1679 C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class>
1680 instance associated with the given class. Unlike methods, attributes
1681 within the MOP are stored as meta-information only. They will be used
1682 later to construct instances from (see C<construct_instance> above).
1683 More details about the attribute meta-objects can be found in the
1684 L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol>
1687 It should be noted that any accessor, reader/writer or predicate
1688 methods which the C<$attribute_meta_object> has will be installed
1689 into the class at this time.
1692 If an attribute already exists for C<$attribute_name>, the old one
1693 will be removed (as well as removing all it's accessors), and then
1696 =item B<has_attribute ($attribute_name)>
1698 Checks to see if this class has an attribute by the name of
1699 C<$attribute_name> and returns a boolean.
1701 =item B<get_attribute ($attribute_name)>
1703 Returns the attribute meta-object associated with C<$attribute_name>,
1704 if none is found, it will return undef.
1706 =item B<remove_attribute ($attribute_name)>
1708 This will remove the attribute meta-object stored at
1709 C<$attribute_name>, then return the removed attribute meta-object.
1712 Removing an attribute will only affect future instances of
1713 the class, it will not make any attempt to remove the attribute from
1714 any existing instances of the class.
1716 It should be noted that any accessor, reader/writer or predicate
1717 methods which the attribute meta-object stored at C<$attribute_name>
1718 has will be removed from the class at this time. This B<will> make
1719 these attributes somewhat inaccessable in previously created
1720 instances. But if you are crazy enough to do this at runtime, then
1721 you are crazy enough to deal with something like this :).
1723 =item B<get_attribute_list>
1725 This returns a list of attribute names which are defined in the local
1726 class. If you want a list of all applicable attributes for a class,
1727 use the C<compute_all_applicable_attributes> method.
1729 =item B<compute_all_applicable_attributes>
1731 =item B<get_all_attributes>
1733 This will traverse the inheritance hierarchy and return a list of all
1734 the applicable L<Class::MOP::Attribute> objects for this class.
1736 C<get_all_attributes> is an alias for consistency with C<get_all_methods>.
1738 =item B<find_attribute_by_name ($attr_name)>
1740 This method will traverse the inheritance hierarchy and find the
1741 first attribute whose name matches C<$attr_name>, then return it.
1742 It will return undef if nothing is found.
1746 =head2 Class Immutability
1750 =item B<make_immutable (%options)>
1752 This method will invoke a tranforamtion upon the class which will
1753 make it immutable. Details of this transformation can be found in
1754 the L<Class::MOP::Immutable> documentation.
1756 =item B<make_mutable>
1758 This method will reverse tranforamtion upon the class which
1761 =item B<get_immutable_transformer>
1763 Return a transformer suitable for making this class immutable or, if this
1764 class is immutable, the transformer used to make it immutable.
1766 =item B<get_immutable_options>
1768 If the class is immutable, return the options used to make it immutable.
1770 =item B<create_immutable_transformer>
1772 Create a transformer suitable for making this class immutable
1778 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1780 =head1 COPYRIGHT AND LICENSE
1782 Copyright 2006-2009 by Infinity Interactive, Inc.
1784 L<http://www.iinteractive.com>
1786 This library is free software; you can redistribute it and/or modify
1787 it under the same terms as Perl itself.