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) . ")";
190 # this should be sufficient, if you have a
191 # use case where it is not, write a test and
193 my $ANON_CLASS_SERIAL = 0;
196 # we need a sufficiently annoying prefix
197 # this should suffice for now, this is
198 # used in a couple of places below, so
199 # need to put it up here for now.
200 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
204 no warnings 'uninitialized';
205 $self->name =~ /^$ANON_CLASS_PREFIX/;
208 sub create_anon_class {
209 my ($class, %options) = @_;
210 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
211 return $class->create($package_name, %options);
215 # this will only get called for
216 # anon-classes, all other calls
217 # are assumed to occur during
218 # global destruction and so don't
219 # really need to be handled explicitly
223 return if Class::MOP::in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
225 no warnings 'uninitialized';
226 return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
227 # Moose does a weird thing where it replaces the metaclass for
228 # class when fixing metaclass incompatibility. In that case,
229 # we don't want to clean out the namespace now. We can detect
230 # that because Moose will explicitly update the singleton
231 # cache in Class::MOP.
232 my $current_meta = Class::MOP::get_metaclass_by_name($self->name);
233 return if $current_meta ne $self;
235 my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
237 foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
238 delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
240 delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
245 # creating classes with MOP ...
248 my ( $class, @args ) = @_;
250 unshift @args, 'package' if @args % 2 == 1;
252 my (%options) = @args;
253 my $package_name = $options{package};
255 (ref $options{superclasses} eq 'ARRAY')
256 || confess "You must pass an ARRAY ref of superclasses"
257 if exists $options{superclasses};
259 (ref $options{attributes} eq 'ARRAY')
260 || confess "You must pass an ARRAY ref of attributes"
261 if exists $options{attributes};
263 (ref $options{methods} eq 'HASH')
264 || confess "You must pass a HASH ref of methods"
265 if exists $options{methods};
267 $class->SUPER::create(%options);
269 my (%initialize_options) = @args;
270 delete @initialize_options{qw(
278 my $meta = $class->initialize( $package_name => %initialize_options );
281 $meta->add_method('meta' => sub {
282 $class->initialize(ref($_[0]) || $_[0]);
285 $meta->superclasses(@{$options{superclasses}})
286 if exists $options{superclasses};
288 # process attributes first, so that they can
289 # install accessors, but locally defined methods
290 # can then overwrite them. It is maybe a little odd, but
291 # I think this should be the order of things.
292 if (exists $options{attributes}) {
293 foreach my $attr (@{$options{attributes}}) {
294 $meta->add_attribute($attr);
297 if (exists $options{methods}) {
298 foreach my $method_name (keys %{$options{methods}}) {
299 $meta->add_method($method_name, $options{methods}->{$method_name});
308 # all these attribute readers will be bootstrapped
309 # away in the Class::MOP bootstrap section
311 sub get_attribute_map { $_[0]->{'attributes'} }
312 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
313 sub method_metaclass { $_[0]->{'method_metaclass'} }
314 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
315 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
317 # Instance Construction & Cloning
323 # we need to protect the integrity of the
324 # Class::MOP::Class singletons here, so we
325 # delegate this to &construct_class_instance
326 # which will deal with the singletons
327 return $class->construct_class_instance(@_)
328 if $class->name->isa('Class::MOP::Class');
329 return $class->construct_instance(@_);
332 sub construct_instance {
334 my $params = @_ == 1 ? $_[0] : {@_};
335 my $meta_instance = $class->get_meta_instance();
336 my $instance = $meta_instance->create_instance();
337 foreach my $attr ($class->compute_all_applicable_attributes()) {
338 $attr->initialize_instance_slot($meta_instance, $instance, $params);
341 # this will only work for a HASH instance type
342 if ($class->is_anon_class) {
343 (Scalar::Util::reftype($instance) eq 'HASH')
344 || confess "Currently only HASH based instances are supported with instance of anon-classes";
346 # At some point we should make this official
347 # as a reserved slot name, but right now I am
348 # going to keep it here.
349 # my $RESERVED_MOP_SLOT = '__MOP__';
350 $instance->{'__MOP__'} = $class;
356 sub get_meta_instance {
358 $self->{'_meta_instance'} ||= $self->create_meta_instance();
361 sub create_meta_instance {
364 my $instance = $self->instance_metaclass->new(
365 associated_metaclass => $self,
366 attributes => [ $self->compute_all_applicable_attributes() ],
369 $self->add_meta_instance_dependencies()
370 if $instance->is_dependent_on_superclasses();
377 my $instance = shift;
378 (blessed($instance) && $instance->isa($class->name))
379 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
382 # we need to protect the integrity of the
383 # Class::MOP::Class singletons here, they
384 # should not be cloned.
385 return $instance if $instance->isa('Class::MOP::Class');
386 $class->clone_instance($instance, @_);
390 my ($class, $instance, %params) = @_;
392 || confess "You can only clone instances, ($instance) is not a blessed instance";
393 my $meta_instance = $class->get_meta_instance();
394 my $clone = $meta_instance->clone_instance($instance);
395 foreach my $attr ($class->compute_all_applicable_attributes()) {
396 if ( defined( my $init_arg = $attr->init_arg ) ) {
397 if (exists $params{$init_arg}) {
398 $attr->set_value($clone, $params{$init_arg});
405 sub rebless_instance {
406 my ($self, $instance, %params) = @_;
409 if ($instance->can('meta')) {
410 ($instance->meta->isa('Class::MOP::Class'))
411 || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
412 $old_metaclass = $instance->meta;
415 $old_metaclass = $self->initialize(ref($instance));
418 my $meta_instance = $self->get_meta_instance();
420 $self->name->isa($old_metaclass->name)
421 || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
424 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
425 $meta_instance->rebless_instance_structure($_[1], $self);
427 foreach my $attr ( $self->compute_all_applicable_attributes ) {
428 if ( $attr->has_value($instance) ) {
429 if ( defined( my $init_arg = $attr->init_arg ) ) {
430 $params{$init_arg} = $attr->get_value($instance)
431 unless exists $params{$init_arg};
434 $attr->set_value($instance, $attr->get_value($instance));
439 foreach my $attr ($self->compute_all_applicable_attributes) {
440 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
450 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
453 @{$self->get_package_symbol($var_spec)} = @supers;
456 # on 5.8 and below, we need to call
457 # a method to get Perl to detect
458 # a cycle in the class hierarchy
459 my $class = $self->name;
463 # we need to check the metaclass
464 # compatibility here so that we can
465 # be sure that the superclass is
466 # not potentially creating an issues
467 # we don't know about
469 $self->check_metaclass_compatibility();
470 $self->update_meta_instance_dependencies();
472 @{$self->get_package_symbol($var_spec)};
478 my $super_class = $self->name;
480 if ( Class::MOP::HAVE_ISAREV() ) {
481 return @{ $super_class->mro::get_isarev() };
485 my $find_derived_classes;
486 $find_derived_classes = sub {
487 my ($outer_class) = @_;
489 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
492 for my $symbol ( keys %$symbol_table_hashref ) {
493 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
494 my $inner_class = $1;
496 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
500 ? "${outer_class}::$inner_class"
503 if ( $class->isa($super_class) and $class ne $super_class ) {
504 push @derived_classes, $class;
507 next SYMBOL if $class eq 'main'; # skip 'main::*'
509 $find_derived_classes->($class);
513 my $root_class = q{};
514 $find_derived_classes->($root_class);
516 undef $find_derived_classes;
518 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
520 return @derived_classes;
526 return @{ mro::get_linear_isa( (shift)->name ) };
529 sub class_precedence_list {
531 my $name = $self->name;
533 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
535 # We need to check for circular inheritance here
536 # if we are are not on 5.10, cause 5.8 detects it
537 # late. This will do nothing if all is well, and
538 # blow up otherwise. Yes, it's an ugly hack, better
539 # suggestions are welcome.
541 ($name || return)->isa('This is a test for circular inheritance')
544 # if our mro is c3, we can
545 # just grab the linear_isa
546 if (mro::get_mro($name) eq 'c3') {
547 return @{ mro::get_linear_isa($name) }
551 # we can't grab the linear_isa for dfs
552 # since it has all the duplicates
557 $self->initialize($_)->class_precedence_list()
558 } $self->superclasses()
565 sub wrap_method_body {
566 my ( $self, %args ) = @_;
568 ('CODE' eq ref $args{body})
569 || confess "Your code block must be a CODE reference";
571 $self->method_metaclass->wrap(
572 package_name => $self->name,
578 my ($self, $method_name, $method) = @_;
579 (defined $method_name && $method_name)
580 || confess "You must define a method name";
583 if (blessed($method)) {
584 $body = $method->body;
585 if ($method->package_name ne $self->name) {
586 $method = $method->clone(
587 package_name => $self->name,
589 ) if $method->can('clone');
594 $method = $self->wrap_method_body( body => $body, name => $method_name );
597 $method->attach_to_class($self);
599 # This used to call get_method_map, which meant we would build all
600 # the method objects for the class just because we added one
601 # method. This is hackier, but quicker too.
602 $self->{methods}{$method_name} = $method;
604 my $full_method_name = ($self->name . '::' . $method_name);
605 $self->add_package_symbol(
606 { sigil => '&', type => 'CODE', name => $method_name },
607 Class::MOP::subname($full_method_name => $body)
612 my $fetch_and_prepare_method = sub {
613 my ($self, $method_name) = @_;
614 my $wrapped_metaclass = $self->wrapped_method_metaclass;
616 my $method = $self->get_method($method_name);
617 # if we dont have local ...
619 # try to find the next method
620 $method = $self->find_next_method_by_name($method_name);
621 # die if it does not exist
623 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
624 # and now make sure to wrap it
625 # even if it is already wrapped
626 # because we need a new sub ref
627 $method = $wrapped_metaclass->wrap($method);
630 # now make sure we wrap it properly
631 $method = $wrapped_metaclass->wrap($method)
632 unless $method->isa($wrapped_metaclass);
634 $self->add_method($method_name => $method);
638 sub add_before_method_modifier {
639 my ($self, $method_name, $method_modifier) = @_;
640 (defined $method_name && $method_name)
641 || confess "You must pass in a method name";
642 my $method = $fetch_and_prepare_method->($self, $method_name);
643 $method->add_before_modifier(
644 Class::MOP::subname(':before' => $method_modifier)
648 sub add_after_method_modifier {
649 my ($self, $method_name, $method_modifier) = @_;
650 (defined $method_name && $method_name)
651 || confess "You must pass in a method name";
652 my $method = $fetch_and_prepare_method->($self, $method_name);
653 $method->add_after_modifier(
654 Class::MOP::subname(':after' => $method_modifier)
658 sub add_around_method_modifier {
659 my ($self, $method_name, $method_modifier) = @_;
660 (defined $method_name && $method_name)
661 || confess "You must pass in a method name";
662 my $method = $fetch_and_prepare_method->($self, $method_name);
663 $method->add_around_modifier(
664 Class::MOP::subname(':around' => $method_modifier)
669 # the methods above used to be named like this:
670 # ${pkg}::${method}:(before|after|around)
671 # but this proved problematic when using one modifier
672 # to wrap multiple methods (something which is likely
673 # to happen pretty regularly IMO). So instead of naming
674 # it like this, I have chosen to just name them purely
675 # with their modifier names, like so:
676 # :(before|after|around)
677 # The fact is that in a stack trace, it will be fairly
678 # evident from the context what method they are attached
679 # to, and so don't need the fully qualified name.
685 $self->add_method(@_);
689 my ($self, $method_name) = @_;
690 (defined $method_name && $method_name)
691 || confess "You must define a method name";
693 exists $self->{methods}{$method_name} || exists $self->get_method_map->{$method_name};
697 my ($self, $method_name) = @_;
698 (defined $method_name && $method_name)
699 || confess "You must define a method name";
701 return $self->{methods}{$method_name} || $self->get_method_map->{$method_name};
705 my ($self, $method_name) = @_;
706 (defined $method_name && $method_name)
707 || confess "You must define a method name";
709 my $removed_method = delete $self->get_method_map->{$method_name};
711 $self->remove_package_symbol(
712 { sigil => '&', type => 'CODE', name => $method_name }
715 $removed_method->detach_from_class if $removed_method;
717 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
719 return $removed_method;
722 sub get_method_list {
724 keys %{$self->get_method_map};
727 sub find_method_by_name {
728 my ($self, $method_name) = @_;
729 (defined $method_name && $method_name)
730 || confess "You must define a method name to find";
731 foreach my $class ($self->linearized_isa) {
732 # fetch the meta-class ...
733 my $meta = $self->initialize($class);
734 return $meta->get_method($method_name)
735 if $meta->has_method($method_name);
740 sub get_all_methods {
742 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
743 return values %methods;
747 sub compute_all_applicable_methods {
751 class => $_->package_name,
752 code => $_, # sigh, overloading
754 } shift->get_all_methods(@_);
757 sub get_all_method_names {
760 grep { $uniq{$_}++ == 0 } map { $_->name } $self->get_all_methods;
763 sub find_all_methods_by_name {
764 my ($self, $method_name) = @_;
765 (defined $method_name && $method_name)
766 || confess "You must define a method name to find";
768 foreach my $class ($self->linearized_isa) {
769 # fetch the meta-class ...
770 my $meta = $self->initialize($class);
772 name => $method_name,
774 code => $meta->get_method($method_name)
775 } if $meta->has_method($method_name);
780 sub find_next_method_by_name {
781 my ($self, $method_name) = @_;
782 (defined $method_name && $method_name)
783 || confess "You must define a method name to find";
784 my @cpl = $self->linearized_isa;
785 shift @cpl; # discard ourselves
786 foreach my $class (@cpl) {
787 # fetch the meta-class ...
788 my $meta = $self->initialize($class);
789 return $meta->get_method($method_name)
790 if $meta->has_method($method_name);
799 # either we have an attribute object already
800 # or we need to create one from the args provided
801 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
802 # make sure it is derived from the correct type though
803 ($attribute->isa('Class::MOP::Attribute'))
804 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
806 # first we attach our new attribute
807 # because it might need certain information
808 # about the class which it is attached to
809 $attribute->attach_to_class($self);
811 # then we remove attributes of a conflicting
812 # name here so that we can properly detach
813 # the old attr object, and remove any
814 # accessors it would have generated
815 if ( $self->has_attribute($attribute->name) ) {
816 $self->remove_attribute($attribute->name);
818 $self->invalidate_meta_instances();
821 # then onto installing the new accessors
822 $self->get_attribute_map->{$attribute->name} = $attribute;
824 # invalidate package flag here
825 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
827 $self->remove_attribute($attribute->name);
834 sub update_meta_instance_dependencies {
837 if ( $self->{meta_instance_dependencies} ) {
838 return $self->add_meta_instance_dependencies;
842 sub add_meta_instance_dependencies {
845 $self->remove_meta_instance_dependencies;
847 my @attrs = $self->compute_all_applicable_attributes();
850 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
852 foreach my $class ( @classes ) {
853 $class->add_dependent_meta_instance($self);
856 $self->{meta_instance_dependencies} = \@classes;
859 sub remove_meta_instance_dependencies {
862 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
863 foreach my $class ( @$classes ) {
864 $class->remove_dependent_meta_instance($self);
874 sub add_dependent_meta_instance {
875 my ( $self, $metaclass ) = @_;
876 push @{ $self->{dependent_meta_instances} }, $metaclass;
879 sub remove_dependent_meta_instance {
880 my ( $self, $metaclass ) = @_;
881 my $name = $metaclass->name;
882 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
885 sub invalidate_meta_instances {
887 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
890 sub invalidate_meta_instance {
892 undef $self->{_meta_instance};
896 my ($self, $attribute_name) = @_;
897 (defined $attribute_name && $attribute_name)
898 || confess "You must define an attribute name";
899 exists $self->get_attribute_map->{$attribute_name};
903 my ($self, $attribute_name) = @_;
904 (defined $attribute_name && $attribute_name)
905 || confess "You must define an attribute name";
906 return $self->get_attribute_map->{$attribute_name}
908 # this will return undef anyway, so no need ...
909 # if $self->has_attribute($attribute_name);
913 sub remove_attribute {
914 my ($self, $attribute_name) = @_;
915 (defined $attribute_name && $attribute_name)
916 || confess "You must define an attribute name";
917 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
918 return unless defined $removed_attribute;
919 delete $self->get_attribute_map->{$attribute_name};
920 $self->invalidate_meta_instances();
921 $removed_attribute->remove_accessors();
922 $removed_attribute->detach_from_class();
923 return $removed_attribute;
926 sub get_attribute_list {
928 keys %{$self->get_attribute_map};
931 sub get_all_attributes {
932 shift->compute_all_applicable_attributes(@_);
935 sub compute_all_applicable_attributes {
937 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
938 return values %attrs;
941 sub find_attribute_by_name {
942 my ($self, $attr_name) = @_;
943 foreach my $class ($self->linearized_isa) {
944 # fetch the meta-class ...
945 my $meta = $self->initialize($class);
946 return $meta->get_attribute($attr_name)
947 if $meta->has_attribute($attr_name);
952 # check if we can reinitialize
956 # if any local attr is defined
957 return if $self->get_attribute_list;
959 # or any non-declared methods
960 if ( my @methods = values %{ $self->get_method_map } ) {
961 my $metaclass = $self->method_metaclass;
962 foreach my $method ( @methods ) {
963 return if $method->isa("Class::MOP::Method::Generated");
964 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
974 sub is_immutable { 0 }
977 # Why I changed this (groditi)
978 # - One Metaclass may have many Classes through many Metaclass instances
979 # - One Metaclass should only have one Immutable Transformer instance
980 # - Each Class may have different Immutabilizing options
981 # - Therefore each Metaclass instance may have different Immutabilizing options
982 # - We need to store one Immutable Transformer instance per Metaclass
983 # - We need to store one set of Immutable Transformer options per Class
984 # - Upon make_mutable we may delete the Immutabilizing options
985 # - We could clean the immutable Transformer instance when there is no more
986 # immutable Classes of that type, but we can also keep it in case
987 # another class with this same Metaclass becomes immutable. It is a case
988 # of trading of storing an instance to avoid unnecessary instantiations of
989 # Immutable Transformers. You may view this as a memory leak, however
990 # Because we have few Metaclasses, in practice it seems acceptable
991 # - To allow Immutable Transformers instances to be cleaned up we could weaken
992 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
996 my %IMMUTABLE_TRANSFORMERS;
997 my %IMMUTABLE_OPTIONS;
999 sub get_immutable_options {
1001 return if $self->is_mutable;
1002 confess "unable to find immutabilizing options"
1003 unless exists $IMMUTABLE_OPTIONS{$self->name};
1004 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1005 delete $options{IMMUTABLE_TRANSFORMER};
1009 sub get_immutable_transformer {
1011 if( $self->is_mutable ){
1012 return $IMMUTABLE_TRANSFORMERS{$self->name} ||= $self->create_immutable_transformer;
1014 confess "unable to find transformer for immutable class"
1015 unless exists $IMMUTABLE_OPTIONS{$self->name};
1016 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1019 sub make_immutable {
1023 my $transformer = $self->get_immutable_transformer;
1024 $transformer->make_metaclass_immutable($self, \%options);
1025 $IMMUTABLE_OPTIONS{$self->name} =
1026 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1028 if( exists $options{debug} && $options{debug} ){
1029 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1030 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1038 return if $self->is_mutable;
1039 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1040 confess "unable to find immutabilizing options" unless ref $options;
1041 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1042 $transformer->make_metaclass_mutable($self, $options);
1047 sub create_immutable_transformer {
1049 my $class = Class::MOP::Immutable->new($self, {
1050 read_only => [qw/superclasses/],
1057 remove_package_symbol
1060 class_precedence_list => 'ARRAY',
1061 linearized_isa => 'ARRAY', # FIXME perl 5.10 memoizes this on its own, no need?
1062 get_all_methods => 'ARRAY',
1063 get_all_method_names => 'ARRAY',
1064 #get_all_attributes => 'ARRAY', # it's an alias, no need, but maybe in the future
1065 compute_all_applicable_attributes => 'ARRAY',
1066 get_meta_instance => 'SCALAR',
1067 get_method_map => 'SCALAR',
1070 # this is ugly, but so are typeglobs,
1071 # so whattayahgonnadoboutit
1074 add_package_symbol => sub {
1075 my $original = shift;
1076 confess "Cannot add package symbols to an immutable metaclass"
1077 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1079 # This is a workaround for a bug in 5.8.1 which thinks that
1080 # goto $original->body
1081 # is trying to go to a label
1082 my $body = $original->body;
1098 Class::MOP::Class - Class Meta Object
1102 # assuming that class Foo
1103 # has been defined, you can
1105 # use this for introspection ...
1107 # add a method to Foo ...
1108 Foo->meta->add_method( 'bar' => sub {...} )
1110 # get a list of all the classes searched
1111 # the method dispatcher in the correct order
1112 Foo->meta->class_precedence_list()
1114 # remove a method from Foo
1115 Foo->meta->remove_method('bar');
1117 # or use this to actually create classes ...
1119 Class::MOP::Class->create(
1122 superclasses => ['Foo'],
1124 Class::MOP:: : Attribute->new('$bar'),
1125 Class::MOP:: : Attribute->new('$baz'),
1128 calculate_bar => sub {...},
1129 construct_baz => sub {...}
1136 This is the largest and currently most complex part of the Perl 5
1137 meta-object protocol. It controls the introspection and
1138 manipulation of Perl 5 classes (and it can create them too). The
1139 best way to understand what this module can do, is to read the
1140 documentation for each of it's methods.
1144 B<Class::MOP::Class> is a subclass of L<Class::MOP::Module>
1148 =head2 Self Introspection
1154 This will return a B<Class::MOP::Class> instance which is related
1155 to this class. Thereby allowing B<Class::MOP::Class> to actually
1158 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1159 bootstrap this module by installing a number of attribute meta-objects
1160 into it's metaclass. This will allow this class to reap all the benifits
1161 of the MOP when subclassing it.
1165 =head2 Class construction
1167 These methods will handle creating B<Class::MOP::Class> objects,
1168 which can be used to both create new classes, and analyze
1169 pre-existing classes.
1171 This module will internally store references to all the instances
1172 you create with these methods, so that they do not need to be
1173 created any more than nessecary. Basically, they are singletons.
1177 =item B<create ($package_name,
1178 version =E<gt> ?$version,
1179 authority =E<gt> ?$authority,
1180 superclasses =E<gt> ?@superclasses,
1181 methods =E<gt> ?%methods,
1182 attributes =E<gt> ?%attributes)>
1184 This returns a B<Class::MOP::Class> object, bringing the specified
1185 C<$package_name> into existence and adding any of the C<$version>,
1186 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1189 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1190 methods =E<gt> ?%methods,
1191 attributes =E<gt> ?%attributes)>
1193 This will create an anonymous class, it works much like C<create> but
1194 it does not need a C<$package_name>. Instead it will create a suitably
1195 unique package name for you to stash things into.
1197 On very important distinction is that anon classes are destroyed once
1198 the metaclass they are attached to goes out of scope. In the DESTROY
1199 method, the created package will be removed from the symbol table.
1201 It is also worth noting that any instances created with an anon-class
1202 will keep a special reference to the anon-meta which will prevent the
1203 anon-class from going out of scope until all instances of it have also
1204 been destroyed. This however only works for HASH based instance types,
1205 as we use a special reserved slot (C<__MOP__>) to store this.
1207 =item B<initialize ($package_name, %options)>
1209 This initializes and returns returns a B<Class::MOP::Class> object for
1210 a given a C<$package_name>. If a metaclass already exists for the
1211 package, it simply returns it instead of creating a new one.
1213 =item B<construct_class_instance (%options)>
1215 This will construct an instance of B<Class::MOP::Class>, it is
1216 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1217 to use C<construct_instance> once all the bootstrapping is done. This
1218 method is used internally by C<initialize> and should never be called
1219 from outside of that method really.
1221 =item B<check_metaclass_compatibility>
1223 This method is called as the very last thing in the
1224 C<construct_class_instance> method. This will check that the
1225 metaclass you are creating is compatible with the metaclasses of all
1226 your ancestors. For more inforamtion about metaclass compatibility
1227 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1229 =item B<update_package_cache_flag>
1231 This will reset the package cache flag for this particular metaclass
1232 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1233 function. This is very rarely needed from outside of C<Class::MOP::Class>
1234 but in some cases you might want to use it, so it is here.
1236 =item B<reset_package_cache_flag>
1238 Clears the package cache flag to announce to the internals that we need
1239 to rebuild the method map.
1241 =item B<add_meta_instance_dependencies>
1243 Registers this class as dependent on its superclasses.
1245 Only superclasses from which this class inherits attributes will be added.
1247 =item B<remove_meta_instance_dependencies>
1249 Unregisters this class from its superclasses.
1251 =item B<update_meta_instance_dependencies>
1253 Reregisters if necessary.
1255 =item B<add_dependent_meta_instance> $metaclass
1257 Registers the class as having a meta instance dependent on this class.
1259 =item B<remove_dependent_meta_instance> $metaclass
1261 Remove the class from the list of dependent classes.
1263 =item B<invalidate_meta_instances>
1265 Clears the cached meta instance for this metaclass and all of the registered
1266 classes with dependent meta instances.
1268 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1271 =item B<invalidate_meta_instance>
1273 Used by C<invalidate_meta_instances>.
1277 =head2 Object instance construction and cloning
1279 These methods are B<entirely optional>, it is up to you whether you want
1284 =item B<instance_metaclass>
1286 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1287 for more information on the instance metaclasses.
1289 =item B<get_meta_instance>
1291 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1292 of a new instance of the class.
1294 =item B<create_meta_instance>
1296 Called by C<get_meta_instance> if necessary.
1298 =item B<new_object (%params)>
1300 This is a convience method for creating a new object of the class, and
1301 blessing it into the appropriate package as well. Ideally your class
1302 would call a C<new> this method like so:
1305 my ($class, %param) = @_;
1306 $class->meta->new_object(%params);
1309 =item B<construct_instance (%params)>
1311 This method is used to construct an instance structure suitable for
1312 C<bless>-ing into your package of choice. It works in conjunction
1313 with the Attribute protocol to collect all applicable attributes.
1315 This will construct an instance using a HASH ref as storage
1316 (currently only HASH references are supported). This will collect all
1317 the applicable attributes and layout out the fields in the HASH ref,
1318 it will then initialize them using either use the corresponding key
1319 in C<%params> or any default value or initializer found in the
1320 attribute meta-object.
1322 =item B<clone_object ($instance, %params)>
1324 This is a convience method for cloning an object instance, then
1325 blessing it into the appropriate package. This method will call
1326 C<clone_instance>, which performs a shallow copy of the object,
1327 see that methods documentation for more details. Ideally your
1328 class would call a C<clone> this method like so:
1330 sub MyClass::clone {
1331 my ($self, %param) = @_;
1332 $self->meta->clone_object($self, %params);
1335 =item B<clone_instance($instance, %params)>
1337 This method is a compliment of C<construct_instance> (which means if
1338 you override C<construct_instance>, you need to override this one too),
1339 and clones the instance shallowly.
1341 The cloned structure returned is (like with C<construct_instance>) an
1342 unC<bless>ed HASH reference, it is your responsibility to then bless
1343 this cloned structure into the right class (which C<clone_object> will
1346 As of 0.11, this method will clone the C<$instance> structure shallowly,
1347 as opposed to the deep cloning implemented in prior versions. After much
1348 thought, research and discussion, I have decided that anything but basic
1349 shallow cloning is outside the scope of the meta-object protocol. I
1350 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1351 is too I<context-specific> to be part of the MOP.
1353 =item B<rebless_instance($instance, ?%params)>
1355 This will change the class of C<$instance> to the class of the invoking
1356 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1357 itself. You may pass in optional C<%params> which are like constructor
1358 params and will override anything already defined in the instance.
1362 =head2 Informational
1364 These are a few predicate methods for asking information about the class.
1368 =item B<is_anon_class>
1370 This returns true if the class is a C<Class::MOP::Class> created anon class.
1374 This returns true if the class is still mutable.
1376 =item B<is_immutable>
1378 This returns true if the class has been made immutable.
1380 =item B<is_pristine>
1382 Checks whether the class has any data that will be lost if C<reinitialize> is
1387 =head2 Inheritance Relationships
1391 =item B<superclasses (?@superclasses)>
1393 This is a read-write attribute which represents the superclass
1394 relationships of the class the B<Class::MOP::Class> instance is
1395 associated with. Basically, it can get and set the C<@ISA> for you.
1397 =item B<class_precedence_list>
1399 This computes the a list of all the class's ancestors in the same order
1400 in which method dispatch will be done. This is similair to what
1401 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1403 =item B<linearized_isa>
1405 This returns a list based on C<class_precedence_list> but with all
1410 This returns a list of subclasses for this class.
1418 =item B<get_method_map>
1420 Returns a HASH ref of name to L<Class::MOP::Method> instance mapping
1423 =item B<method_metaclass>
1425 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1426 for more information on the method metaclasses.
1428 =item B<wrap_method_body(%attrs)>
1430 Wrap a code ref (C<$attrs{body>) with C<method_metaclass>.
1432 =item B<add_method ($method_name, $method)>
1434 This will take a C<$method_name> and CODE reference or meta method
1435 objectand install it into the class's package.
1437 You are strongly encouraged to pass a meta method object instead of a
1438 code reference. If you do so, that object gets stored as part of the
1439 class's method map, providing more useful information about the method
1442 When you provide a method object, this method will clone that object
1443 if the object's package name does not match the class name. This lets
1444 us track the original source of any methods added from other classes
1445 (notably Moose roles).
1448 This does absolutely nothing special to C<$method>
1449 other than use B<Sub::Name> to make sure it is tagged with the
1450 correct name, and therefore show up correctly in stack traces and
1453 =item B<has_method ($method_name)>
1455 This just provides a simple way to check if the class implements
1456 a specific C<$method_name>. It will I<not> however, attempt to check
1457 if the class inherits the method (use C<UNIVERSAL::can> for that).
1459 This will correctly handle functions defined outside of the package
1460 that use a fully qualified name (C<sub Package::name { ... }>).
1462 This will correctly handle functions renamed with B<Sub::Name> and
1463 installed using the symbol tables. However, if you are naming the
1464 subroutine outside of the package scope, you must use the fully
1465 qualified name, including the package name, for C<has_method> to
1466 correctly identify it.
1468 This will attempt to correctly ignore functions imported from other
1469 packages using B<Exporter>. It breaks down if the function imported
1470 is an C<__ANON__> sub (such as with C<use constant>), which very well
1471 may be a valid method being applied to the class.
1473 In short, this method cannot always be trusted to determine if the
1474 C<$method_name> is actually a method. However, it will DWIM about
1475 90% of the time, so it's a small trade off I think.
1477 =item B<get_method ($method_name)>
1479 This will return a Class::MOP::Method instance related to the specified
1480 C<$method_name>, or return undef if that method does not exist.
1482 The Class::MOP::Method is codifiable, so you can use it like a normal
1483 CODE reference, see L<Class::MOP::Method> for more information.
1485 =item B<find_method_by_name ($method_name)>
1487 This will return a L<Class::MOP::Method> instance for the specified
1488 C<$method_name>, or return undef if that method does not exist.
1490 Unlike C<get_method> this will also look in the superclasses.
1492 =item B<remove_method ($method_name)>
1494 This will attempt to remove a given C<$method_name> from the class.
1495 It will return the L<Class::MOP::Method> instance that it has removed,
1496 and will attempt to use B<Sub::Name> to clear the methods associated
1499 =item B<get_method_list>
1501 This will return a list of method names for all I<locally> defined
1502 methods. It does B<not> provide a list of all applicable methods,
1503 including any inherited ones. If you want a list of all applicable
1504 methods, use the C<compute_all_applicable_methods> method.
1506 =item B<get_all_methods>
1508 This will traverse the inheritance hierarchy and return a list of all
1509 the applicable L<Class::MOP::Method> objects for this class.
1511 =item B<compute_all_applicable_methods>
1515 This method returns a list of hashes describing the all the methods of the
1518 Use L<get_all_methods>, which is easier/better/faster. This method predates
1519 L<Class::MOP::Method>.
1521 =item B<get_all_method_names>
1523 This will traverse the inheritance hierarchy and return a list of all the
1524 applicable method names for this class. Duplicate names are removed, but the
1525 order the methods come out is not defined.
1527 =item B<find_all_methods_by_name ($method_name)>
1529 This will traverse the inheritence hierarchy and locate all methods
1530 with a given C<$method_name>. Similar to
1531 C<compute_all_applicable_methods> it returns a list of HASH references
1532 with the following information; method name (which will always be the
1533 same as C<$method_name>), the name of the class in which the method
1534 lives and a CODE reference for the actual method.
1536 The list of methods produced is a distinct list, meaning there are no
1537 duplicates in it. This is especially useful for things like object
1538 initialization and destruction where you only want the method called
1539 once, and in the correct order.
1541 =item B<find_next_method_by_name ($method_name)>
1543 This will return the first method to match a given C<$method_name> in
1544 the superclasses, this is basically equivalent to calling
1545 C<SUPER::$method_name>, but it can be dispatched at runtime.
1547 =item B<alias_method ($method_name, $method)>
1549 B<NOTE>: This method is now deprecated. Just use C<add_method>
1554 =head2 Method Modifiers
1556 Method modifiers are a concept borrowed from CLOS, in which a method
1557 can be wrapped with I<before>, I<after> and I<around> method modifiers
1558 that will be called everytime the method is called.
1560 =head3 How method modifiers work?
1562 Method modifiers work by wrapping the original method and then replacing
1563 it in the classes symbol table. The wrappers will handle calling all the
1564 modifiers in the appropariate orders and preserving the calling context
1565 for the original method.
1567 Each method modifier serves a particular purpose, which may not be
1568 obvious to users of other method wrapping modules. To start with, the
1569 return values of I<before> and I<after> modifiers are ignored. This is
1570 because thier purpose is B<not> to filter the input and output of the
1571 primary method (this is done with an I<around> modifier). This may seem
1572 like an odd restriction to some, but doing this allows for simple code
1573 to be added at the begining or end of a method call without jeapordizing
1574 the normal functioning of the primary method or placing any extra
1575 responsibility on the code of the modifier. Of course if you have more
1576 complex needs, then use the I<around> modifier, which uses a variation
1577 of continutation passing style to allow for a high degree of flexibility.
1579 Before and around modifiers are called in last-defined-first-called order,
1580 while after modifiers are called in first-defined-first-called order. So
1581 the call tree might looks something like this:
1593 To see examples of using method modifiers, see the following examples
1594 included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
1595 F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
1596 classic CLOS usage example in the test F<017_add_method_modifier.t>.
1598 =head3 What is the performance impact?
1600 Of course there is a performance cost associated with method modifiers,
1601 but we have made every effort to make that cost be directly proportional
1602 to the amount of modifier features you utilize.
1604 The wrapping method does it's best to B<only> do as much work as it
1605 absolutely needs to. In order to do this we have moved some of the
1606 performance costs to set-up time, where they are easier to amortize.
1608 All this said, my benchmarks have indicated the following:
1610 simple wrapper with no modifiers 100% slower
1611 simple wrapper with simple before modifier 400% slower
1612 simple wrapper with simple after modifier 450% slower
1613 simple wrapper with simple around modifier 500-550% slower
1614 simple wrapper with all 3 modifiers 1100% slower
1616 These numbers may seem daunting, but you must remember, every feature
1617 comes with some cost. To put things in perspective, just doing a simple
1618 C<AUTOLOAD> which does nothing but extract the name of the method called
1619 and return it costs about 400% over a normal method call.
1623 =item B<add_before_method_modifier ($method_name, $code)>
1625 This will wrap the method at C<$method_name> and the supplied C<$code>
1626 will be passed the C<@_> arguments, and called before the original
1627 method is called. As specified above, the return value of the I<before>
1628 method modifiers is ignored, and it's ability to modify C<@_> is
1629 fairly limited. If you need to do either of these things, use an
1630 C<around> method modifier.
1632 =item B<add_after_method_modifier ($method_name, $code)>
1634 This will wrap the method at C<$method_name> so that the original
1635 method will be called, it's return values stashed, and then the
1636 supplied C<$code> will be passed the C<@_> arguments, and called.
1637 As specified above, the return value of the I<after> method
1638 modifiers is ignored, and it cannot modify the return values of
1639 the original method. If you need to do either of these things, use an
1640 C<around> method modifier.
1642 =item B<add_around_method_modifier ($method_name, $code)>
1644 This will wrap the method at C<$method_name> so that C<$code>
1645 will be called and passed the original method as an extra argument
1646 at the begining of the C<@_> argument list. This is a variation of
1647 continuation passing style, where the function prepended to C<@_>
1648 can be considered a continuation. It is up to C<$code> if it calls
1649 the original method or not, there is no restriction on what the
1650 C<$code> can or cannot do.
1656 It should be noted that since there is no one consistent way to define
1657 the attributes of a class in Perl 5. These methods can only work with
1658 the information given, and can not easily discover information on
1659 their own. See L<Class::MOP::Attribute> for more details.
1663 =item B<attribute_metaclass>
1665 Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute>
1666 for more information on the attribute metaclasses.
1668 =item B<get_attribute_map>
1670 This returns a HASH ref of name to attribute meta-object mapping.
1672 =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))>
1674 This stores the C<$attribute_meta_object> (or creates one from the
1675 C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class>
1676 instance associated with the given class. Unlike methods, attributes
1677 within the MOP are stored as meta-information only. They will be used
1678 later to construct instances from (see C<construct_instance> above).
1679 More details about the attribute meta-objects can be found in the
1680 L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol>
1683 It should be noted that any accessor, reader/writer or predicate
1684 methods which the C<$attribute_meta_object> has will be installed
1685 into the class at this time.
1688 If an attribute already exists for C<$attribute_name>, the old one
1689 will be removed (as well as removing all it's accessors), and then
1692 =item B<has_attribute ($attribute_name)>
1694 Checks to see if this class has an attribute by the name of
1695 C<$attribute_name> and returns a boolean.
1697 =item B<get_attribute ($attribute_name)>
1699 Returns the attribute meta-object associated with C<$attribute_name>,
1700 if none is found, it will return undef.
1702 =item B<remove_attribute ($attribute_name)>
1704 This will remove the attribute meta-object stored at
1705 C<$attribute_name>, then return the removed attribute meta-object.
1708 Removing an attribute will only affect future instances of
1709 the class, it will not make any attempt to remove the attribute from
1710 any existing instances of the class.
1712 It should be noted that any accessor, reader/writer or predicate
1713 methods which the attribute meta-object stored at C<$attribute_name>
1714 has will be removed from the class at this time. This B<will> make
1715 these attributes somewhat inaccessable in previously created
1716 instances. But if you are crazy enough to do this at runtime, then
1717 you are crazy enough to deal with something like this :).
1719 =item B<get_attribute_list>
1721 This returns a list of attribute names which are defined in the local
1722 class. If you want a list of all applicable attributes for a class,
1723 use the C<compute_all_applicable_attributes> method.
1725 =item B<compute_all_applicable_attributes>
1727 =item B<get_all_attributes>
1729 This will traverse the inheritance hierarchy and return a list of all
1730 the applicable L<Class::MOP::Attribute> objects for this class.
1732 C<get_all_attributes> is an alias for consistency with C<get_all_methods>.
1734 =item B<find_attribute_by_name ($attr_name)>
1736 This method will traverse the inheritance hierarchy and find the
1737 first attribute whose name matches C<$attr_name>, then return it.
1738 It will return undef if nothing is found.
1742 =head2 Class Immutability
1746 =item B<make_immutable (%options)>
1748 This method will invoke a tranforamtion upon the class which will
1749 make it immutable. Details of this transformation can be found in
1750 the L<Class::MOP::Immutable> documentation.
1752 =item B<make_mutable>
1754 This method will reverse tranforamtion upon the class which
1757 =item B<get_immutable_transformer>
1759 Return a transformer suitable for making this class immutable or, if this
1760 class is immutable, the transformer used to make it immutable.
1762 =item B<get_immutable_options>
1764 If the class is immutable, return the options used to make it immutable.
1766 =item B<create_immutable_transformer>
1768 Create a transformer suitable for making this class immutable
1774 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1776 =head1 COPYRIGHT AND LICENSE
1778 Copyright 2006-2009 by Infinity Interactive, Inc.
1780 L<http://www.iinteractive.com>
1782 This library is free software; you can redistribute it and/or modify
1783 it under the same terms as Perl itself.