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 = '0.65';
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 $meta->check_metaclass_compatability();
90 Class::MOP::store_metaclass_by_name($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,
117 # inherited from Class::MOP::Module
119 'authority' => \undef,
120 # defined in Class::MOP::Class
121 'superclasses' => \undef,
125 'attribute_metaclass' => $options->{'attribute_metaclass'} || 'Class::MOP::Attribute',
126 'method_metaclass' => $options->{'method_metaclass'} || 'Class::MOP::Method',
127 'instance_metaclass' => $options->{'instance_metaclass'} || 'Class::MOP::Instance',
131 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
132 sub update_package_cache_flag {
135 # we can manually update the cache number
136 # since we are actually adding the method
137 # to our cache as well. This avoids us
138 # having to regenerate the method_map.
140 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
143 sub check_metaclass_compatability {
146 # this is always okay ...
147 return if ref($self) eq 'Class::MOP::Class' &&
148 $self->instance_metaclass eq 'Class::MOP::Instance';
150 my @class_list = $self->linearized_isa;
151 shift @class_list; # shift off $self->name
153 foreach my $class_name (@class_list) {
154 my $meta = Class::MOP::get_metaclass_by_name($class_name) || next;
157 # we need to deal with the possibility
158 # of class immutability here, and then
159 # get the name of the class appropriately
160 my $meta_type = ($meta->is_immutable
161 ? $meta->get_mutable_metaclass_name()
164 ($self->isa($meta_type))
165 || confess $self->name . "->meta => (" . (ref($self)) . ")" .
166 " is not compatible with the " .
167 $class_name . "->meta => (" . ($meta_type) . ")";
169 # we also need to check that instance metaclasses
170 # are compatabile in the same the class.
171 ($self->instance_metaclass->isa($meta->instance_metaclass))
172 || confess $self->name . "->meta->instance_metaclass => (" . ($self->instance_metaclass) . ")" .
173 " is not compatible with the " .
174 $class_name . "->meta->instance_metaclass => (" . ($meta->instance_metaclass) . ")";
182 # this should be sufficient, if you have a
183 # use case where it is not, write a test and
185 my $ANON_CLASS_SERIAL = 0;
188 # we need a sufficiently annoying prefix
189 # this should suffice for now, this is
190 # used in a couple of places below, so
191 # need to put it up here for now.
192 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
196 no warnings 'uninitialized';
197 $self->name =~ /^$ANON_CLASS_PREFIX/;
200 sub create_anon_class {
201 my ($class, %options) = @_;
202 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
203 return $class->create($package_name, %options);
207 # this will only get called for
208 # anon-classes, all other calls
209 # are assumed to occur during
210 # global destruction and so don't
211 # really need to be handled explicitly
215 return if Class::MOP::in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
217 no warnings 'uninitialized';
218 return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
219 my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
221 foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
222 delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
224 delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
229 # creating classes with MOP ...
232 my ( $class, @args ) = @_;
234 unshift @args, 'package' if @args % 2 == 1;
236 my (%options) = @args;
237 my $package_name = $options{package};
239 (defined $package_name && $package_name)
240 || confess "You must pass a package name";
242 (ref $options{superclasses} eq 'ARRAY')
243 || confess "You must pass an ARRAY ref of superclasses"
244 if exists $options{superclasses};
246 (ref $options{attributes} eq 'ARRAY')
247 || confess "You must pass an ARRAY ref of attributes"
248 if exists $options{attributes};
250 (ref $options{methods} eq 'HASH')
251 || confess "You must pass an HASH ref of methods"
252 if exists $options{methods};
254 my $code = "package $package_name;";
255 $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';"
256 if exists $options{version};
257 $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';"
258 if exists $options{authority};
261 confess "creation of $package_name failed : $@" if $@;
263 my $meta = $class->initialize($package_name);
266 $meta->add_method('meta' => sub {
267 $class->initialize(ref($_[0]) || $_[0]);
270 $meta->superclasses(@{$options{superclasses}})
271 if exists $options{superclasses};
273 # process attributes first, so that they can
274 # install accessors, but locally defined methods
275 # can then overwrite them. It is maybe a little odd, but
276 # I think this should be the order of things.
277 if (exists $options{attributes}) {
278 foreach my $attr (@{$options{attributes}}) {
279 $meta->add_attribute($attr);
282 if (exists $options{methods}) {
283 foreach my $method_name (keys %{$options{methods}}) {
284 $meta->add_method($method_name, $options{methods}->{$method_name});
293 # all these attribute readers will be bootstrapped
294 # away in the Class::MOP bootstrap section
296 sub get_attribute_map { $_[0]->{'attributes'} }
297 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
298 sub method_metaclass { $_[0]->{'method_metaclass'} }
299 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
302 # this is a prime canidate for conversion to XS
306 my $current = Class::MOP::check_package_cache_flag($self->name);
308 if (defined $self->{'_package_cache_flag'} && $self->{'_package_cache_flag'} == $current) {
309 return $self->{'methods'} ||= {};
312 $self->{_package_cache_flag} = $current;
314 my $map = $self->{'methods'} ||= {};
316 my $class_name = $self->name;
317 my $method_metaclass = $self->method_metaclass;
319 my %all_code = $self->get_all_package_symbols('CODE');
321 foreach my $symbol (keys %all_code) {
322 my $code = $all_code{$symbol};
324 next if exists $map->{$symbol} &&
325 defined $map->{$symbol} &&
326 $map->{$symbol}->body == $code;
328 my ($pkg, $name) = Class::MOP::get_code_info($code);
331 # in 5.10 constant.pm the constants show up
332 # as being in the right package, but in pre-5.10
333 # they show up as constant::__ANON__ so we
334 # make an exception here to be sure that things
335 # work as expected in both.
337 unless ($pkg eq 'constant' && $name eq '__ANON__') {
338 next if ($pkg || '') ne $class_name ||
339 (($name || '') ne '__ANON__' && ($pkg || '') ne $class_name);
342 $map->{$symbol} = $method_metaclass->wrap(
344 associated_metaclass => $self,
345 package_name => $class_name,
353 # Instance Construction & Cloning
359 # we need to protect the integrity of the
360 # Class::MOP::Class singletons here, so we
361 # delegate this to &construct_class_instance
362 # which will deal with the singletons
363 return $class->construct_class_instance(@_)
364 if $class->name->isa('Class::MOP::Class');
365 return $class->construct_instance(@_);
368 sub construct_instance {
370 my $params = @_ == 1 ? $_[0] : {@_};
371 my $meta_instance = $class->get_meta_instance();
372 my $instance = $meta_instance->create_instance();
373 foreach my $attr ($class->compute_all_applicable_attributes()) {
374 $attr->initialize_instance_slot($meta_instance, $instance, $params);
377 # this will only work for a HASH instance type
378 if ($class->is_anon_class) {
379 (Scalar::Util::reftype($instance) eq 'HASH')
380 || confess "Currently only HASH based instances are supported with instance of anon-classes";
382 # At some point we should make this official
383 # as a reserved slot name, but right now I am
384 # going to keep it here.
385 # my $RESERVED_MOP_SLOT = '__MOP__';
386 $instance->{'__MOP__'} = $class;
392 sub get_meta_instance {
394 $self->{'_meta_instance'} ||= $self->create_meta_instance();
397 sub create_meta_instance {
400 my $instance = $self->instance_metaclass->new(
401 associated_metaclass => $self,
402 attributes => [ $self->compute_all_applicable_attributes() ],
405 $self->add_meta_instance_dependencies()
406 if $instance->is_dependent_on_superclasses();
413 my $instance = shift;
414 (blessed($instance) && $instance->isa($class->name))
415 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
418 # we need to protect the integrity of the
419 # Class::MOP::Class singletons here, they
420 # should not be cloned.
421 return $instance if $instance->isa('Class::MOP::Class');
422 $class->clone_instance($instance, @_);
426 my ($class, $instance, %params) = @_;
428 || confess "You can only clone instances, ($instance) is not a blessed instance";
429 my $meta_instance = $class->get_meta_instance();
430 my $clone = $meta_instance->clone_instance($instance);
431 foreach my $attr ($class->compute_all_applicable_attributes()) {
432 if ( defined( my $init_arg = $attr->init_arg ) ) {
433 if (exists $params{$init_arg}) {
434 $attr->set_value($clone, $params{$init_arg});
441 sub rebless_instance {
442 my ($self, $instance, %params) = @_;
445 if ($instance->can('meta')) {
446 ($instance->meta->isa('Class::MOP::Class'))
447 || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
448 $old_metaclass = $instance->meta;
451 $old_metaclass = $self->initialize(ref($instance));
454 my $meta_instance = $self->get_meta_instance();
456 $self->name->isa($old_metaclass->name)
457 || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
460 $meta_instance->rebless_instance_structure($instance, $self);
462 foreach my $attr ( $self->compute_all_applicable_attributes ) {
463 if ( $attr->has_value($instance) ) {
464 if ( defined( my $init_arg = $attr->init_arg ) ) {
465 $params{$init_arg} = $attr->get_value($instance)
466 unless exists $params{$init_arg};
469 $attr->set_value($instance, $attr->get_value($instance));
474 foreach my $attr ($self->compute_all_applicable_attributes) {
475 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
485 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
488 @{$self->get_package_symbol($var_spec)} = @supers;
490 # we need to check the metaclass
491 # compatibility here so that we can
492 # be sure that the superclass is
493 # not potentially creating an issues
494 # we don't know about
495 $self->check_metaclass_compatability();
496 $self->update_meta_instance_dependencies();
498 @{$self->get_package_symbol($var_spec)};
504 my $super_class = $self->name;
506 if ( Class::MOP::HAVE_ISAREV() ) {
507 return @{ $super_class->mro::get_isarev() };
511 my $find_derived_classes;
512 $find_derived_classes = sub {
513 my ($outer_class) = @_;
515 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
518 for my $symbol ( keys %$symbol_table_hashref ) {
519 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
520 my $inner_class = $1;
522 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
526 ? "${outer_class}::$inner_class"
529 if ( $class->isa($super_class) and $class ne $super_class ) {
530 push @derived_classes, $class;
533 next SYMBOL if $class eq 'main'; # skip 'main::*'
535 $find_derived_classes->($class);
539 my $root_class = q{};
540 $find_derived_classes->($root_class);
542 undef $find_derived_classes;
544 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
546 return @derived_classes;
552 return @{ mro::get_linear_isa( (shift)->name ) };
555 sub class_precedence_list {
557 my $name = $self->name;
559 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
561 # We need to check for circular inheritance here
562 # if we are are not on 5.10, cause 5.8 detects it
563 # late. This will do nothing if all is well, and
564 # blow up otherwise. Yes, it's an ugly hack, better
565 # suggestions are welcome.
567 ($name || return)->isa('This is a test for circular inheritance')
570 # if our mro is c3, we can
571 # just grab the linear_isa
572 if (mro::get_mro($name) eq 'c3') {
573 return @{ mro::get_linear_isa($name) }
577 # we can't grab the linear_isa for dfs
578 # since it has all the duplicates
583 $self->initialize($_)->class_precedence_list()
584 } $self->superclasses()
591 sub wrap_method_body {
592 my ( $self, %args ) = @_;
594 my $body = delete $args{body}; # delete is for compat
596 ('CODE' eq ref($body))
597 || confess "Your code block must be a CODE reference";
599 $self->method_metaclass->wrap( $body => (
600 package_name => $self->name,
606 my ($self, $method_name, $method) = @_;
607 (defined $method_name && $method_name)
608 || confess "You must define a method name";
611 if (blessed($method)) {
612 $body = $method->body;
613 if ($method->package_name ne $self->name) {
614 $method = $method->clone(
615 package_name => $self->name,
617 ) if $method->can('clone');
622 $method = $self->wrap_method_body( body => $body, name => $method_name );
625 $method->attach_to_class($self);
627 $self->get_method_map->{$method_name} = $method;
629 my $full_method_name = ($self->name . '::' . $method_name);
630 $self->add_package_symbol(
631 { sigil => '&', type => 'CODE', name => $method_name },
632 Class::MOP::subname($full_method_name => $body)
635 $self->update_package_cache_flag; # still valid, since we just added the method to the map, and if it was invalid before that then get_method_map updated it
639 my $fetch_and_prepare_method = sub {
640 my ($self, $method_name) = @_;
642 my $method = $self->get_method($method_name);
643 # if we dont have local ...
645 # try to find the next method
646 $method = $self->find_next_method_by_name($method_name);
647 # die if it does not exist
649 || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name;
650 # and now make sure to wrap it
651 # even if it is already wrapped
652 # because we need a new sub ref
653 $method = Class::MOP::Method::Wrapped->wrap($method);
656 # now make sure we wrap it properly
657 $method = Class::MOP::Method::Wrapped->wrap($method)
658 unless $method->isa('Class::MOP::Method::Wrapped');
660 $self->add_method($method_name => $method);
664 sub add_before_method_modifier {
665 my ($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_before_modifier(
670 Class::MOP::subname(':before' => $method_modifier)
674 sub add_after_method_modifier {
675 my ($self, $method_name, $method_modifier) = @_;
676 (defined $method_name && $method_name)
677 || confess "You must pass in a method name";
678 my $method = $fetch_and_prepare_method->($self, $method_name);
679 $method->add_after_modifier(
680 Class::MOP::subname(':after' => $method_modifier)
684 sub add_around_method_modifier {
685 my ($self, $method_name, $method_modifier) = @_;
686 (defined $method_name && $method_name)
687 || confess "You must pass in a method name";
688 my $method = $fetch_and_prepare_method->($self, $method_name);
689 $method->add_around_modifier(
690 Class::MOP::subname(':around' => $method_modifier)
695 # the methods above used to be named like this:
696 # ${pkg}::${method}:(before|after|around)
697 # but this proved problematic when using one modifier
698 # to wrap multiple methods (something which is likely
699 # to happen pretty regularly IMO). So instead of naming
700 # it like this, I have chosen to just name them purely
701 # with their modifier names, like so:
702 # :(before|after|around)
703 # The fact is that in a stack trace, it will be fairly
704 # evident from the context what method they are attached
705 # to, and so don't need the fully qualified name.
711 $self->add_method(@_);
715 my ($self, $method_name) = @_;
716 (defined $method_name && $method_name)
717 || confess "You must define a method name";
719 exists $self->get_method_map->{$method_name};
723 my ($self, $method_name) = @_;
724 (defined $method_name && $method_name)
725 || confess "You must define a method name";
728 # I don't really need this here, because
729 # if the method_map is missing a key it
730 # will just return undef for me now
731 # return unless $self->has_method($method_name);
733 return $self->get_method_map->{$method_name};
737 my ($self, $method_name) = @_;
738 (defined $method_name && $method_name)
739 || confess "You must define a method name";
741 my $removed_method = delete $self->get_method_map->{$method_name};
743 $self->remove_package_symbol(
744 { sigil => '&', type => 'CODE', name => $method_name }
747 $removed_method->detach_from_class if $removed_method;
749 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
751 return $removed_method;
754 sub get_method_list {
756 keys %{$self->get_method_map};
759 sub find_method_by_name {
760 my ($self, $method_name) = @_;
761 (defined $method_name && $method_name)
762 || confess "You must define a method name to find";
763 foreach my $class ($self->linearized_isa) {
764 # fetch the meta-class ...
765 my $meta = $self->initialize($class);
766 return $meta->get_method($method_name)
767 if $meta->has_method($method_name);
772 sub get_all_methods {
774 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
775 return values %methods;
779 sub compute_all_applicable_methods {
783 class => $_->package_name,
784 code => $_, # sigh, overloading
786 } shift->get_all_methods(@_);
789 sub find_all_methods_by_name {
790 my ($self, $method_name) = @_;
791 (defined $method_name && $method_name)
792 || confess "You must define a method name to find";
794 foreach my $class ($self->linearized_isa) {
795 # fetch the meta-class ...
796 my $meta = $self->initialize($class);
798 name => $method_name,
800 code => $meta->get_method($method_name)
801 } if $meta->has_method($method_name);
806 sub find_next_method_by_name {
807 my ($self, $method_name) = @_;
808 (defined $method_name && $method_name)
809 || confess "You must define a method name to find";
810 my @cpl = $self->linearized_isa;
811 shift @cpl; # discard ourselves
812 foreach my $class (@cpl) {
813 # fetch the meta-class ...
814 my $meta = $self->initialize($class);
815 return $meta->get_method($method_name)
816 if $meta->has_method($method_name);
825 # either we have an attribute object already
826 # or we need to create one from the args provided
827 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
828 # make sure it is derived from the correct type though
829 ($attribute->isa('Class::MOP::Attribute'))
830 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
832 # first we attach our new attribute
833 # because it might need certain information
834 # about the class which it is attached to
835 $attribute->attach_to_class($self);
837 # then we remove attributes of a conflicting
838 # name here so that we can properly detach
839 # the old attr object, and remove any
840 # accessors it would have generated
841 if ( $self->has_attribute($attribute->name) ) {
842 $self->remove_attribute($attribute->name);
844 $self->invalidate_meta_instances();
847 # then onto installing the new accessors
848 $self->get_attribute_map->{$attribute->name} = $attribute;
850 # invalidate package flag here
851 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
853 $self->remove_attribute($attribute->name);
860 sub update_meta_instance_dependencies {
863 if ( $self->{meta_instance_dependencies} ) {
864 return $self->add_meta_instance_dependencies;
868 sub add_meta_instance_dependencies {
871 $self->remove_meta_instance_depdendencies;
873 my @attrs = $self->compute_all_applicable_attributes();
876 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
878 foreach my $class ( @classes ) {
879 $class->add_dependent_meta_instance($self);
882 $self->{meta_instance_dependencies} = \@classes;
885 sub remove_meta_instance_depdendencies {
888 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
889 foreach my $class ( @$classes ) {
890 $class->remove_dependent_meta_instance($self);
900 sub add_dependent_meta_instance {
901 my ( $self, $metaclass ) = @_;
902 push @{ $self->{dependent_meta_instances} }, $metaclass;
905 sub remove_dependent_meta_instance {
906 my ( $self, $metaclass ) = @_;
907 my $name = $metaclass->name;
908 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
911 sub invalidate_meta_instances {
913 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
916 sub invalidate_meta_instance {
918 undef $self->{_meta_instance};
922 my ($self, $attribute_name) = @_;
923 (defined $attribute_name && $attribute_name)
924 || confess "You must define an attribute name";
925 exists $self->get_attribute_map->{$attribute_name};
929 my ($self, $attribute_name) = @_;
930 (defined $attribute_name && $attribute_name)
931 || confess "You must define an attribute name";
932 return $self->get_attribute_map->{$attribute_name}
934 # this will return undef anyway, so no need ...
935 # if $self->has_attribute($attribute_name);
939 sub remove_attribute {
940 my ($self, $attribute_name) = @_;
941 (defined $attribute_name && $attribute_name)
942 || confess "You must define an attribute name";
943 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
944 return unless defined $removed_attribute;
945 delete $self->get_attribute_map->{$attribute_name};
946 $self->invalidate_meta_instances();
947 $removed_attribute->remove_accessors();
948 $removed_attribute->detach_from_class();
949 return $removed_attribute;
952 sub get_attribute_list {
954 keys %{$self->get_attribute_map};
957 sub get_all_attributes {
958 shift->compute_all_applicable_attributes(@_);
961 sub compute_all_applicable_attributes {
963 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
964 return values %attrs;
967 sub find_attribute_by_name {
968 my ($self, $attr_name) = @_;
969 foreach my $class ($self->linearized_isa) {
970 # fetch the meta-class ...
971 my $meta = $self->initialize($class);
972 return $meta->get_attribute($attr_name)
973 if $meta->has_attribute($attr_name);
978 # check if we can reinitialize
982 # if any local attr is defined
983 return if $self->get_attribute_list;
985 # or any non-declared methods
986 if ( my @methods = values %{ $self->get_method_map } ) {
987 my $metaclass = $self->method_metaclass;
988 foreach my $method ( @methods ) {
989 return if $method->isa("Class::MOP::Method::Generated");
990 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1000 sub is_immutable { 0 }
1003 # Why I changed this (groditi)
1004 # - One Metaclass may have many Classes through many Metaclass instances
1005 # - One Metaclass should only have one Immutable Transformer instance
1006 # - Each Class may have different Immutabilizing options
1007 # - Therefore each Metaclass instance may have different Immutabilizing options
1008 # - We need to store one Immutable Transformer instance per Metaclass
1009 # - We need to store one set of Immutable Transformer options per Class
1010 # - Upon make_mutable we may delete the Immutabilizing options
1011 # - We could clean the immutable Transformer instance when there is no more
1012 # immutable Classes of that type, but we can also keep it in case
1013 # another class with this same Metaclass becomes immutable. It is a case
1014 # of trading of storing an instance to avoid unnecessary instantiations of
1015 # Immutable Transformers. You may view this as a memory leak, however
1016 # Because we have few Metaclasses, in practice it seems acceptable
1017 # - To allow Immutable Transformers instances to be cleaned up we could weaken
1018 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
1022 my %IMMUTABLE_TRANSFORMERS;
1023 my %IMMUTABLE_OPTIONS;
1025 sub get_immutable_options {
1027 return if $self->is_mutable;
1028 confess "unable to find immutabilizing options"
1029 unless exists $IMMUTABLE_OPTIONS{$self->name};
1030 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1031 delete $options{IMMUTABLE_TRANSFORMER};
1035 sub get_immutable_transformer {
1037 if( $self->is_mutable ){
1038 my $class = ref $self || $self;
1039 return $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer;
1041 confess "unable to find transformer for immutable class"
1042 unless exists $IMMUTABLE_OPTIONS{$self->name};
1043 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1046 sub make_immutable {
1050 my $transformer = $self->get_immutable_transformer;
1051 $transformer->make_metaclass_immutable($self, \%options);
1052 $IMMUTABLE_OPTIONS{$self->name} =
1053 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1055 if( exists $options{debug} && $options{debug} ){
1056 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1057 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1065 return if $self->is_mutable;
1066 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1067 confess "unable to find immutabilizing options" unless ref $options;
1068 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1069 $transformer->make_metaclass_mutable($self, $options);
1074 sub create_immutable_transformer {
1076 my $class = Class::MOP::Immutable->new($self, {
1077 read_only => [qw/superclasses/],
1084 remove_package_symbol
1087 class_precedence_list => 'ARRAY',
1088 linearized_isa => 'ARRAY', # FIXME perl 5.10 memoizes this on its own, no need?
1089 get_all_methods => 'ARRAY',
1090 #get_all_attributes => 'ARRAY', # it's an alias, no need, but maybe in the future
1091 compute_all_applicable_attributes => 'ARRAY',
1092 get_meta_instance => 'SCALAR',
1093 get_method_map => 'SCALAR',
1096 # this is ugly, but so are typeglobs,
1097 # so whattayahgonnadoboutit
1100 add_package_symbol => sub {
1101 my $original = shift;
1102 confess "Cannot add package symbols to an immutable metaclass"
1103 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1105 # This is a workaround for a bug in 5.8.1 which thinks that
1106 # goto $original->body
1107 # is trying to go to a label
1108 my $body = $original->body;
1124 Class::MOP::Class - Class Meta Object
1128 # assuming that class Foo
1129 # has been defined, you can
1131 # use this for introspection ...
1133 # add a method to Foo ...
1134 Foo->meta->add_method('bar' => sub { ... })
1136 # get a list of all the classes searched
1137 # the method dispatcher in the correct order
1138 Foo->meta->class_precedence_list()
1140 # remove a method from Foo
1141 Foo->meta->remove_method('bar');
1143 # or use this to actually create classes ...
1145 Class::MOP::Class->create('Bar' => (
1147 superclasses => [ 'Foo' ],
1149 Class::MOP:::Attribute->new('$bar'),
1150 Class::MOP:::Attribute->new('$baz'),
1153 calculate_bar => sub { ... },
1154 construct_baz => sub { ... }
1160 This is the largest and currently most complex part of the Perl 5
1161 meta-object protocol. It controls the introspection and
1162 manipulation of Perl 5 classes (and it can create them too). The
1163 best way to understand what this module can do, is to read the
1164 documentation for each of it's methods.
1168 =head2 Self Introspection
1174 This will return a B<Class::MOP::Class> instance which is related
1175 to this class. Thereby allowing B<Class::MOP::Class> to actually
1178 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1179 bootstrap this module by installing a number of attribute meta-objects
1180 into it's metaclass. This will allow this class to reap all the benifits
1181 of the MOP when subclassing it.
1185 =head2 Class construction
1187 These methods will handle creating B<Class::MOP::Class> objects,
1188 which can be used to both create new classes, and analyze
1189 pre-existing classes.
1191 This module will internally store references to all the instances
1192 you create with these methods, so that they do not need to be
1193 created any more than nessecary. Basically, they are singletons.
1197 =item B<create ($package_name,
1198 version =E<gt> ?$version,
1199 authority =E<gt> ?$authority,
1200 superclasses =E<gt> ?@superclasses,
1201 methods =E<gt> ?%methods,
1202 attributes =E<gt> ?%attributes)>
1204 This returns a B<Class::MOP::Class> object, bringing the specified
1205 C<$package_name> into existence and adding any of the C<$version>,
1206 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1209 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1210 methods =E<gt> ?%methods,
1211 attributes =E<gt> ?%attributes)>
1213 This will create an anonymous class, it works much like C<create> but
1214 it does not need a C<$package_name>. Instead it will create a suitably
1215 unique package name for you to stash things into.
1217 On very important distinction is that anon classes are destroyed once
1218 the metaclass they are attached to goes out of scope. In the DESTROY
1219 method, the created package will be removed from the symbol table.
1221 It is also worth noting that any instances created with an anon-class
1222 will keep a special reference to the anon-meta which will prevent the
1223 anon-class from going out of scope until all instances of it have also
1224 been destroyed. This however only works for HASH based instance types,
1225 as we use a special reserved slot (C<__MOP__>) to store this.
1227 =item B<initialize ($package_name, %options)>
1229 This initializes and returns returns a B<Class::MOP::Class> object
1230 for a given a C<$package_name>.
1232 =item B<construct_class_instance (%options)>
1234 This will construct an instance of B<Class::MOP::Class>, it is
1235 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1236 to use C<construct_instance> once all the bootstrapping is done. This
1237 method is used internally by C<initialize> and should never be called
1238 from outside of that method really.
1240 =item B<check_metaclass_compatability>
1242 This method is called as the very last thing in the
1243 C<construct_class_instance> method. This will check that the
1244 metaclass you are creating is compatible with the metaclasses of all
1245 your ancestors. For more inforamtion about metaclass compatibility
1246 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1248 =item B<update_package_cache_flag>
1250 This will reset the package cache flag for this particular metaclass
1251 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1252 function. This is very rarely needed from outside of C<Class::MOP::Class>
1253 but in some cases you might want to use it, so it is here.
1255 =item B<reset_package_cache_flag>
1257 Clears the package cache flag to announce to the internals that we need
1258 to rebuild the method map.
1260 =item B<add_meta_instance_dependencies>
1262 Registers this class as dependent on its superclasses.
1264 Only superclasses from which this class inherits attributes will be added.
1266 =item B<remove_meta_instance_depdendencies>
1268 Unregisters this class from its superclasses.
1270 =item B<update_meta_instance_dependencies>
1272 Reregisters if necessary.
1274 =item B<add_dependent_meta_instance> $metaclass
1276 Registers the class as having a meta instance dependent on this class.
1278 =item B<remove_dependent_meta_instance> $metaclass
1280 Remove the class from the list of dependent classes.
1282 =item B<invalidate_meta_instances>
1284 Clears the cached meta instance for this metaclass and all of the registered
1285 classes with dependent meta instances.
1287 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1290 =item B<invalidate_meta_instance>
1292 Used by C<invalidate_meta_instances>.
1296 =head2 Object instance construction and cloning
1298 These methods are B<entirely optional>, it is up to you whether you want
1303 =item B<instance_metaclass>
1305 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1306 for more information on the instance metaclasses.
1308 =item B<get_meta_instance>
1310 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1311 of a new instance of the class.
1313 =item B<create_meta_instance>
1315 Called by C<get_meta_instance> if necessary.
1317 =item B<new_object (%params)>
1319 This is a convience method for creating a new object of the class, and
1320 blessing it into the appropriate package as well. Ideally your class
1321 would call a C<new> this method like so:
1324 my ($class, %param) = @_;
1325 $class->meta->new_object(%params);
1328 =item B<construct_instance (%params)>
1330 This method is used to construct an instance structure suitable for
1331 C<bless>-ing into your package of choice. It works in conjunction
1332 with the Attribute protocol to collect all applicable attributes.
1334 This will construct and instance using a HASH ref as storage
1335 (currently only HASH references are supported). This will collect all
1336 the applicable attributes and layout out the fields in the HASH ref,
1337 it will then initialize them using either use the corresponding key
1338 in C<%params> or any default value or initializer found in the
1339 attribute meta-object.
1341 =item B<clone_object ($instance, %params)>
1343 This is a convience method for cloning an object instance, then
1344 blessing it into the appropriate package. This method will call
1345 C<clone_instance>, which performs a shallow copy of the object,
1346 see that methods documentation for more details. Ideally your
1347 class would call a C<clone> this method like so:
1349 sub MyClass::clone {
1350 my ($self, %param) = @_;
1351 $self->meta->clone_object($self, %params);
1354 =item B<clone_instance($instance, %params)>
1356 This method is a compliment of C<construct_instance> (which means if
1357 you override C<construct_instance>, you need to override this one too),
1358 and clones the instance shallowly.
1360 The cloned structure returned is (like with C<construct_instance>) an
1361 unC<bless>ed HASH reference, it is your responsibility to then bless
1362 this cloned structure into the right class (which C<clone_object> will
1365 As of 0.11, this method will clone the C<$instance> structure shallowly,
1366 as opposed to the deep cloning implemented in prior versions. After much
1367 thought, research and discussion, I have decided that anything but basic
1368 shallow cloning is outside the scope of the meta-object protocol. I
1369 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1370 is too I<context-specific> to be part of the MOP.
1372 =item B<rebless_instance($instance, ?%params)>
1374 This will change the class of C<$instance> to the class of the invoking
1375 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1376 itself. You may pass in optional C<%params> which are like constructor
1377 params and will override anything already defined in the instance.
1381 =head2 Informational
1383 These are a few predicate methods for asking information about the class.
1387 =item B<is_anon_class>
1389 This returns true if the class is a C<Class::MOP::Class> created anon class.
1393 This returns true if the class is still mutable.
1395 =item B<is_immutable>
1397 This returns true if the class has been made immutable.
1399 =item B<is_pristine>
1401 Checks whether the class has any data that will be lost if C<reinitialize> is
1406 =head2 Inheritance Relationships
1410 =item B<superclasses (?@superclasses)>
1412 This is a read-write attribute which represents the superclass
1413 relationships of the class the B<Class::MOP::Class> instance is
1414 associated with. Basically, it can get and set the C<@ISA> for you.
1416 =item B<class_precedence_list>
1418 This computes the a list of all the class's ancestors in the same order
1419 in which method dispatch will be done. This is similair to what
1420 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1422 =item B<linearized_isa>
1424 This returns a list based on C<class_precedence_list> but with all
1429 This returns a list of subclasses for this class.
1437 =item B<get_method_map>
1439 Returns a HASH ref of name to CODE reference mapping for this class.
1441 =item B<method_metaclass>
1443 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1444 for more information on the method metaclasses.
1446 =item B<wrap_method_body(%attrs)>
1448 Wrap a code ref (C<$attrs{body>) with C<method_metaclass>.
1450 =item B<add_method ($method_name, $method, %attrs)>
1452 This will take a C<$method_name> and CODE reference or meta method
1453 objectand install it into the class's package.
1455 You are strongly encouraged to pass a meta method object instead of a
1456 code reference. If you do so, that object gets stored as part of the
1457 class's method map, providing more useful information about the method
1461 This does absolutely nothing special to C<$method>
1462 other than use B<Sub::Name> to make sure it is tagged with the
1463 correct name, and therefore show up correctly in stack traces and
1466 =item B<has_method ($method_name)>
1468 This just provides a simple way to check if the class implements
1469 a specific C<$method_name>. It will I<not> however, attempt to check
1470 if the class inherits the method (use C<UNIVERSAL::can> for that).
1472 This will correctly handle functions defined outside of the package
1473 that use a fully qualified name (C<sub Package::name { ... }>).
1475 This will correctly handle functions renamed with B<Sub::Name> and
1476 installed using the symbol tables. However, if you are naming the
1477 subroutine outside of the package scope, you must use the fully
1478 qualified name, including the package name, for C<has_method> to
1479 correctly identify it.
1481 This will attempt to correctly ignore functions imported from other
1482 packages using B<Exporter>. It breaks down if the function imported
1483 is an C<__ANON__> sub (such as with C<use constant>), which very well
1484 may be a valid method being applied to the class.
1486 In short, this method cannot always be trusted to determine if the
1487 C<$method_name> is actually a method. However, it will DWIM about
1488 90% of the time, so it's a small trade off I think.
1490 =item B<get_method ($method_name)>
1492 This will return a Class::MOP::Method instance related to the specified
1493 C<$method_name>, or return undef if that method does not exist.
1495 The Class::MOP::Method is codifiable, so you can use it like a normal
1496 CODE reference, see L<Class::MOP::Method> for more information.
1498 =item B<find_method_by_name ($method_name)>
1500 This will return a CODE reference of the specified C<$method_name>,
1501 or return undef if that method does not exist.
1503 Unlike C<get_method> this will also look in the superclasses.
1505 =item B<remove_method ($method_name)>
1507 This will attempt to remove a given C<$method_name> from the class.
1508 It will return the CODE reference that it has removed, and will
1509 attempt to use B<Sub::Name> to clear the methods associated name.
1511 =item B<get_method_list>
1513 This will return a list of method names for all I<locally> defined
1514 methods. It does B<not> provide a list of all applicable methods,
1515 including any inherited ones. If you want a list of all applicable
1516 methods, use the C<compute_all_applicable_methods> method.
1518 =item B<get_all_methods>
1520 This will traverse the inheritance heirachy and return a list of all
1521 the applicable L<Class::MOP::Method> objects for this class.
1523 =item B<compute_all_applicable_methods>
1527 This method returns a list of hashes describing the all the methods of the
1530 Use L<get_all_methods>, which is easier/better/faster. This method predates
1531 L<Class::MOP::Method>.
1533 =item B<find_all_methods_by_name ($method_name)>
1535 This will traverse the inheritence hierarchy and locate all methods
1536 with a given C<$method_name>. Similar to
1537 C<compute_all_applicable_methods> it returns a list of HASH references
1538 with the following information; method name (which will always be the
1539 same as C<$method_name>), the name of the class in which the method
1540 lives and a CODE reference for the actual method.
1542 The list of methods produced is a distinct list, meaning there are no
1543 duplicates in it. This is especially useful for things like object
1544 initialization and destruction where you only want the method called
1545 once, and in the correct order.
1547 =item B<find_next_method_by_name ($method_name)>
1549 This will return the first method to match a given C<$method_name> in
1550 the superclasses, this is basically equivalent to calling
1551 C<SUPER::$method_name>, but it can be dispatched at runtime.
1553 =item B<alias_method ($method_name, $method)>
1555 B<NOTE>: This method is now deprecated. Just use C<add_method>
1560 =head2 Method Modifiers
1562 Method modifiers are a concept borrowed from CLOS, in which a method
1563 can be wrapped with I<before>, I<after> and I<around> method modifiers
1564 that will be called everytime the method is called.
1566 =head3 How method modifiers work?
1568 Method modifiers work by wrapping the original method and then replacing
1569 it in the classes symbol table. The wrappers will handle calling all the
1570 modifiers in the appropariate orders and preserving the calling context
1571 for the original method.
1573 Each method modifier serves a particular purpose, which may not be
1574 obvious to users of other method wrapping modules. To start with, the
1575 return values of I<before> and I<after> modifiers are ignored. This is
1576 because thier purpose is B<not> to filter the input and output of the
1577 primary method (this is done with an I<around> modifier). This may seem
1578 like an odd restriction to some, but doing this allows for simple code
1579 to be added at the begining or end of a method call without jeapordizing
1580 the normal functioning of the primary method or placing any extra
1581 responsibility on the code of the modifier. Of course if you have more
1582 complex needs, then use the I<around> modifier, which uses a variation
1583 of continutation passing style to allow for a high degree of flexibility.
1585 Before and around modifiers are called in last-defined-first-called order,
1586 while after modifiers are called in first-defined-first-called order. So
1587 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 heirachy 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 ($attr_name)>
1740 This method will traverse the inheritance heirachy and find the
1741 first attribute whose name matches C<$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 2006-2008 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.