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 our $AUTHORITY = 'cpan:STEVAN';
17 use base 'Class::MOP::Module';
27 $package_name = shift;
30 $package_name = $options{package};
33 (defined $package_name && $package_name && !ref($package_name))
34 || confess "You must pass a package name and it cannot be blessed";
36 return Class::MOP::get_metaclass_by_name($package_name)
37 || $class->construct_class_instance(package => $package_name, @_);
40 # NOTE: (meta-circularity)
41 # this is a special form of &construct_instance
42 # (see below), which is used to construct class
43 # meta-object instances for any Class::MOP::*
44 # class. All other classes will use the more
45 # normal &construct_instance.
46 sub construct_class_instance {
48 my $options = @_ == 1 ? $_[0] : {@_};
49 my $package_name = $options->{package};
50 (defined $package_name && $package_name)
51 || confess "You must pass a package name";
53 # return the metaclass if we have it cached,
54 # and it is still defined (it has not been
55 # reaped by DESTROY yet, which can happen
56 # annoyingly enough during global destruction)
58 if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) {
63 # we need to deal with the possibility
64 # of class immutability here, and then
65 # get the name of the class appropriately
67 ? ($class->is_immutable
68 ? $class->get_mutable_metaclass_name()
72 # now create the metaclass
74 if ($class eq 'Class::MOP::Class') {
76 $meta = $class->_new($options)
80 # it is safe to use meta here because
81 # class will always be a subclass of
82 # Class::MOP::Class, which defines meta
83 $meta = $class->meta->construct_instance($options)
86 # and check the metaclass compatibility
87 $meta->check_metaclass_compatability();
89 Class::MOP::store_metaclass_by_name($package_name, $meta);
92 # we need to weaken any anon classes
93 # so that they can call DESTROY properly
94 Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class;
101 my $options = @_ == 1 ? $_[0] : {@_};
104 # inherited from Class::MOP::Package
105 'package' => $options->{package},
108 # since the following attributes will
109 # actually be loaded from the symbol
110 # table, and actually bypass the instance
111 # entirely, we can just leave these things
112 # listed here for reference, because they
113 # should not actually have a value associated
115 'namespace' => \undef,
116 # inherited from Class::MOP::Module
118 'authority' => \undef,
119 # defined in Class::MOP::Class
120 'superclasses' => \undef,
124 'attribute_metaclass' => $options->{'attribute_metaclass'} || 'Class::MOP::Attribute',
125 'method_metaclass' => $options->{'method_metaclass'} || 'Class::MOP::Method',
126 'instance_metaclass' => $options->{'instance_metaclass'} || 'Class::MOP::Instance',
130 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
131 sub update_package_cache_flag {
134 # we can manually update the cache number
135 # since we are actually adding the method
136 # to our cache as well. This avoids us
137 # having to regenerate the method_map.
139 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
142 sub check_metaclass_compatability {
145 # this is always okay ...
146 return if ref($self) eq 'Class::MOP::Class' &&
147 $self->instance_metaclass eq 'Class::MOP::Instance';
149 my @class_list = $self->linearized_isa;
150 shift @class_list; # shift off $self->name
152 foreach my $class_name (@class_list) {
153 my $meta = Class::MOP::get_metaclass_by_name($class_name) || next;
156 # we need to deal with the possibility
157 # of class immutability here, and then
158 # get the name of the class appropriately
159 my $meta_type = ($meta->is_immutable
160 ? $meta->get_mutable_metaclass_name()
163 ($self->isa($meta_type))
164 || confess $self->name . "->meta => (" . (ref($self)) . ")" .
165 " is not compatible with the " .
166 $class_name . "->meta => (" . ($meta_type) . ")";
168 # we also need to check that instance metaclasses
169 # are compatabile in the same the class.
170 ($self->instance_metaclass->isa($meta->instance_metaclass))
171 || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" .
172 " is not compatible with the " .
173 $class_name . "->meta => (" . ($meta->instance_metaclass) . ")";
181 # this should be sufficient, if you have a
182 # use case where it is not, write a test and
184 my $ANON_CLASS_SERIAL = 0;
187 # we need a sufficiently annoying prefix
188 # this should suffice for now, this is
189 # used in a couple of places below, so
190 # need to put it up here for now.
191 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
195 no warnings 'uninitialized';
196 $self->name =~ /^$ANON_CLASS_PREFIX/;
199 sub create_anon_class {
200 my ($class, %options) = @_;
201 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
202 return $class->create($package_name, %options);
206 # this will only get called for
207 # anon-classes, all other calls
208 # are assumed to occur during
209 # global destruction and so don't
210 # really need to be handled explicitly
214 return if Class::MOP::in_global_destruction; # it'll happen soon anyway and this just makes things more complicated
216 no warnings 'uninitialized';
217 return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
218 my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
220 foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
221 delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
223 delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
228 # creating classes with MOP ...
231 my ( $class, @args ) = @_;
233 unshift @args, 'package' if @args % 2 == 1;
235 my (%options) = @args;
236 my $package_name = $options{package};
238 (defined $package_name && $package_name)
239 || confess "You must pass a package name";
241 (ref $options{superclasses} eq 'ARRAY')
242 || confess "You must pass an ARRAY ref of superclasses"
243 if exists $options{superclasses};
245 (ref $options{attributes} eq 'ARRAY')
246 || confess "You must pass an ARRAY ref of attributes"
247 if exists $options{attributes};
249 (ref $options{methods} eq 'HASH')
250 || confess "You must pass an HASH ref of methods"
251 if exists $options{methods};
253 my $code = "package $package_name;";
254 $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';"
255 if exists $options{version};
256 $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';"
257 if exists $options{authority};
260 confess "creation of $package_name failed : $@" if $@;
262 my $meta = $class->initialize($package_name);
265 $meta->add_method('meta' => sub {
266 $class->initialize(ref($_[0]) || $_[0]);
269 $meta->superclasses(@{$options{superclasses}})
270 if exists $options{superclasses};
272 # process attributes first, so that they can
273 # install accessors, but locally defined methods
274 # can then overwrite them. It is maybe a little odd, but
275 # I think this should be the order of things.
276 if (exists $options{attributes}) {
277 foreach my $attr (@{$options{attributes}}) {
278 $meta->add_attribute($attr);
281 if (exists $options{methods}) {
282 foreach my $method_name (keys %{$options{methods}}) {
283 $meta->add_method($method_name, $options{methods}->{$method_name});
292 # all these attribute readers will be bootstrapped
293 # away in the Class::MOP bootstrap section
295 sub get_attribute_map { $_[0]->{'attributes'} }
296 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
297 sub method_metaclass { $_[0]->{'method_metaclass'} }
298 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
301 # this is a prime canidate for conversion to XS
305 my $current = Class::MOP::check_package_cache_flag($self->name);
307 if (defined $self->{'_package_cache_flag'} && $self->{'_package_cache_flag'} == $current) {
308 return $self->{'methods'} ||= {};
311 $self->{_package_cache_flag} = $current;
313 my $map = $self->{'methods'} ||= {};
315 my $class_name = $self->name;
316 my $method_metaclass = $self->method_metaclass;
318 my %all_code = $self->get_all_package_symbols('CODE');
320 foreach my $symbol (keys %all_code) {
321 my $code = $all_code{$symbol};
323 next if exists $map->{$symbol} &&
324 defined $map->{$symbol} &&
325 $map->{$symbol}->body == $code;
327 my ($pkg, $name) = Class::MOP::get_code_info($code);
330 # in 5.10 constant.pm the constants show up
331 # as being in the right package, but in pre-5.10
332 # they show up as constant::__ANON__ so we
333 # make an exception here to be sure that things
334 # work as expected in both.
336 unless ($pkg eq 'constant' && $name eq '__ANON__') {
337 next if ($pkg || '') ne $class_name ||
338 (($name || '') ne '__ANON__' && ($pkg || '') ne $class_name);
341 $map->{$symbol} = $method_metaclass->wrap(
343 associated_metaclass => $self,
344 package_name => $class_name,
352 # Instance Construction & Cloning
358 # we need to protect the integrity of the
359 # Class::MOP::Class singletons here, so we
360 # delegate this to &construct_class_instance
361 # which will deal with the singletons
362 return $class->construct_class_instance(@_)
363 if $class->name->isa('Class::MOP::Class');
364 return $class->construct_instance(@_);
367 sub construct_instance {
369 my $params = @_ == 1 ? $_[0] : {@_};
370 my $meta_instance = $class->get_meta_instance();
371 my $instance = $meta_instance->create_instance();
372 foreach my $attr ($class->compute_all_applicable_attributes()) {
373 $attr->initialize_instance_slot($meta_instance, $instance, $params);
376 # this will only work for a HASH instance type
377 if ($class->is_anon_class) {
378 (Scalar::Util::reftype($instance) eq 'HASH')
379 || confess "Currently only HASH based instances are supported with instance of anon-classes";
381 # At some point we should make this official
382 # as a reserved slot name, but right now I am
383 # going to keep it here.
384 # my $RESERVED_MOP_SLOT = '__MOP__';
385 $instance->{'__MOP__'} = $class;
391 sub get_meta_instance {
393 $self->{'_meta_instance'} ||= $self->create_meta_instance();
396 sub create_meta_instance {
399 my $instance = $self->instance_metaclass->new(
400 associated_metaclass => $self,
401 attributes => [ $self->compute_all_applicable_attributes() ],
404 $self->add_meta_instance_dependencies()
405 if $instance->is_dependent_on_superclasses();
412 my $instance = shift;
413 (blessed($instance) && $instance->isa($class->name))
414 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
417 # we need to protect the integrity of the
418 # Class::MOP::Class singletons here, they
419 # should not be cloned.
420 return $instance if $instance->isa('Class::MOP::Class');
421 $class->clone_instance($instance, @_);
425 my ($class, $instance, %params) = @_;
427 || confess "You can only clone instances, ($instance) is not a blessed instance";
428 my $meta_instance = $class->get_meta_instance();
429 my $clone = $meta_instance->clone_instance($instance);
430 foreach my $attr ($class->compute_all_applicable_attributes()) {
431 if ( defined( my $init_arg = $attr->init_arg ) ) {
432 if (exists $params{$init_arg}) {
433 $attr->set_value($clone, $params{$init_arg});
440 sub rebless_instance {
441 my ($self, $instance, %params) = @_;
444 if ($instance->can('meta')) {
445 ($instance->meta->isa('Class::MOP::Class'))
446 || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
447 $old_metaclass = $instance->meta;
450 $old_metaclass = $self->initialize(ref($instance));
453 my $meta_instance = $self->get_meta_instance();
455 $self->name->isa($old_metaclass->name)
456 || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
459 $meta_instance->rebless_instance_structure($instance, $self);
461 foreach my $attr ( $self->compute_all_applicable_attributes ) {
462 if ( $attr->has_value($instance) ) {
463 if ( defined( my $init_arg = $attr->init_arg ) ) {
464 $params{$init_arg} = $attr->get_value($instance)
465 unless exists $params{$init_arg};
468 $attr->set_value($instance, $attr->get_value($instance));
473 foreach my $attr ($self->compute_all_applicable_attributes) {
474 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
484 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
487 @{$self->get_package_symbol($var_spec)} = @supers;
489 # we need to check the metaclass
490 # compatibility here so that we can
491 # be sure that the superclass is
492 # not potentially creating an issues
493 # we don't know about
494 $self->check_metaclass_compatability();
495 $self->update_meta_instance_dependencies();
497 @{$self->get_package_symbol($var_spec)};
503 my $super_class = $self->name;
505 if ( Class::MOP::HAVE_ISAREV() ) {
506 return @{ $super_class->mro::get_isarev() };
510 my $find_derived_classes;
511 $find_derived_classes = sub {
512 my ($outer_class) = @_;
514 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
517 for my $symbol ( keys %$symbol_table_hashref ) {
518 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
519 my $inner_class = $1;
521 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
525 ? "${outer_class}::$inner_class"
528 if ( $class->isa($super_class) and $class ne $super_class ) {
529 push @derived_classes, $class;
532 next SYMBOL if $class eq 'main'; # skip 'main::*'
534 $find_derived_classes->($class);
538 my $root_class = q{};
539 $find_derived_classes->($root_class);
541 undef $find_derived_classes;
543 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
545 return @derived_classes;
551 return @{ mro::get_linear_isa( (shift)->name ) };
554 sub class_precedence_list {
556 my $name = $self->name;
558 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
560 # We need to check for circular inheritance here
561 # if we are are not on 5.10, cause 5.8 detects it
562 # late. This will do nothing if all is well, and
563 # blow up otherwise. Yes, it's an ugly hack, better
564 # suggestions are welcome.
566 ($name || return)->isa('This is a test for circular inheritance')
569 # if our mro is c3, we can
570 # just grab the linear_isa
571 if (mro::get_mro($name) eq 'c3') {
572 return @{ mro::get_linear_isa($name) }
576 # we can't grab the linear_isa for dfs
577 # since it has all the duplicates
582 $self->initialize($_)->class_precedence_list()
583 } $self->superclasses()
591 my ($self, $method_name, $method) = @_;
592 (defined $method_name && $method_name)
593 || confess "You must define a method name";
596 if (blessed($method)) {
597 $body = $method->body;
598 if ($method->package_name ne $self->name &&
599 $method->name ne $method_name) {
600 warn "Hello there, got something for you."
601 . " Method says " . $method->package_name . " " . $method->name
602 . " Class says " . $self->name . " " . $method_name;
603 $method = $method->clone(
604 package_name => $self->name,
606 ) if $method->can('clone');
611 ('CODE' eq ref($body))
612 || confess "Your code block must be a CODE reference";
613 $method = $self->method_metaclass->wrap(
615 package_name => $self->name,
621 $method->attach_to_class($self);
623 $self->get_method_map->{$method_name} = $method;
625 my $full_method_name = ($self->name . '::' . $method_name);
626 $self->add_package_symbol(
627 { sigil => '&', type => 'CODE', name => $method_name },
628 Class::MOP::subname($full_method_name => $body)
631 $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
635 my $fetch_and_prepare_method = sub {
636 my ($self, $method_name) = @_;
638 my $method = $self->get_method($method_name);
639 # if we dont have local ...
641 # try to find the next method
642 $method = $self->find_next_method_by_name($method_name);
643 # die if it does not exist
645 || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name;
646 # and now make sure to wrap it
647 # even if it is already wrapped
648 # because we need a new sub ref
649 $method = Class::MOP::Method::Wrapped->wrap($method);
652 # now make sure we wrap it properly
653 $method = Class::MOP::Method::Wrapped->wrap($method)
654 unless $method->isa('Class::MOP::Method::Wrapped');
656 $self->add_method($method_name => $method);
660 sub add_before_method_modifier {
661 my ($self, $method_name, $method_modifier) = @_;
662 (defined $method_name && $method_name)
663 || confess "You must pass in a method name";
664 my $method = $fetch_and_prepare_method->($self, $method_name);
665 $method->add_before_modifier(
666 Class::MOP::subname(':before' => $method_modifier)
670 sub add_after_method_modifier {
671 my ($self, $method_name, $method_modifier) = @_;
672 (defined $method_name && $method_name)
673 || confess "You must pass in a method name";
674 my $method = $fetch_and_prepare_method->($self, $method_name);
675 $method->add_after_modifier(
676 Class::MOP::subname(':after' => $method_modifier)
680 sub add_around_method_modifier {
681 my ($self, $method_name, $method_modifier) = @_;
682 (defined $method_name && $method_name)
683 || confess "You must pass in a method name";
684 my $method = $fetch_and_prepare_method->($self, $method_name);
685 $method->add_around_modifier(
686 Class::MOP::subname(':around' => $method_modifier)
691 # the methods above used to be named like this:
692 # ${pkg}::${method}:(before|after|around)
693 # but this proved problematic when using one modifier
694 # to wrap multiple methods (something which is likely
695 # to happen pretty regularly IMO). So instead of naming
696 # it like this, I have chosen to just name them purely
697 # with their modifier names, like so:
698 # :(before|after|around)
699 # The fact is that in a stack trace, it will be fairly
700 # evident from the context what method they are attached
701 # to, and so don't need the fully qualified name.
705 my ($self, $method_name, $method) = @_;
706 (defined $method_name && $method_name)
707 || confess "You must define a method name";
709 my $body = (blessed($method) ? $method->body : $method);
710 ('CODE' eq ref($body))
711 || confess "Your code block must be a CODE reference";
713 $self->add_package_symbol(
714 { sigil => '&', type => 'CODE', name => $method_name } => $body
719 my ($self, $method_name) = @_;
720 (defined $method_name && $method_name)
721 || confess "You must define a method name";
723 exists $self->get_method_map->{$method_name};
727 my ($self, $method_name) = @_;
728 (defined $method_name && $method_name)
729 || confess "You must define a method name";
732 # I don't really need this here, because
733 # if the method_map is missing a key it
734 # will just return undef for me now
735 # return unless $self->has_method($method_name);
737 return $self->get_method_map->{$method_name};
741 my ($self, $method_name) = @_;
742 (defined $method_name && $method_name)
743 || confess "You must define a method name";
745 my $removed_method = delete $self->get_method_map->{$method_name};
747 $self->remove_package_symbol(
748 { sigil => '&', type => 'CODE', name => $method_name }
751 $removed_method->detach_from_class if $removed_method;
753 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
755 return $removed_method;
758 sub get_method_list {
760 keys %{$self->get_method_map};
763 sub find_method_by_name {
764 my ($self, $method_name) = @_;
765 (defined $method_name && $method_name)
766 || confess "You must define a method name to find";
767 foreach my $class ($self->linearized_isa) {
768 # fetch the meta-class ...
769 my $meta = $self->initialize($class);
770 return $meta->get_method($method_name)
771 if $meta->has_method($method_name);
776 sub get_all_methods {
778 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
779 return values %methods;
783 sub compute_all_applicable_methods {
787 class => $_->package_name,
788 code => $_, # sigh, overloading
790 } shift->get_all_methods(@_);
793 sub find_all_methods_by_name {
794 my ($self, $method_name) = @_;
795 (defined $method_name && $method_name)
796 || confess "You must define a method name to find";
798 foreach my $class ($self->linearized_isa) {
799 # fetch the meta-class ...
800 my $meta = $self->initialize($class);
802 name => $method_name,
804 code => $meta->get_method($method_name)
805 } if $meta->has_method($method_name);
810 sub find_next_method_by_name {
811 my ($self, $method_name) = @_;
812 (defined $method_name && $method_name)
813 || confess "You must define a method name to find";
814 my @cpl = $self->linearized_isa;
815 shift @cpl; # discard ourselves
816 foreach my $class (@cpl) {
817 # fetch the meta-class ...
818 my $meta = $self->initialize($class);
819 return $meta->get_method($method_name)
820 if $meta->has_method($method_name);
829 # either we have an attribute object already
830 # or we need to create one from the args provided
831 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
832 # make sure it is derived from the correct type though
833 ($attribute->isa('Class::MOP::Attribute'))
834 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
836 # first we attach our new attribute
837 # because it might need certain information
838 # about the class which it is attached to
839 $attribute->attach_to_class($self);
841 # then we remove attributes of a conflicting
842 # name here so that we can properly detach
843 # the old attr object, and remove any
844 # accessors it would have generated
845 if ( $self->has_attribute($attribute->name) ) {
846 $self->remove_attribute($attribute->name);
848 $self->invalidate_meta_instances();
851 # then onto installing the new accessors
852 $self->get_attribute_map->{$attribute->name} = $attribute;
854 # invalidate package flag here
855 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
857 $self->remove_attribute($attribute->name);
864 sub update_meta_instance_dependencies {
867 if ( $self->{meta_instance_dependencies} ) {
868 return $self->add_meta_instance_dependencies;
872 sub add_meta_instance_dependencies {
875 $self->remove_meta_instance_depdendencies;
877 my @attrs = $self->compute_all_applicable_attributes();
880 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
882 foreach my $class ( @classes ) {
883 $class->add_dependent_meta_instance($self);
886 $self->{meta_instance_dependencies} = \@classes;
889 sub remove_meta_instance_depdendencies {
892 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
893 foreach my $class ( @$classes ) {
894 $class->remove_dependent_meta_instance($self);
904 sub add_dependent_meta_instance {
905 my ( $self, $metaclass ) = @_;
906 push @{ $self->{dependent_meta_instances} }, $metaclass;
909 sub remove_dependent_meta_instance {
910 my ( $self, $metaclass ) = @_;
911 my $name = $metaclass->name;
912 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
915 sub invalidate_meta_instances {
917 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
920 sub invalidate_meta_instance {
922 undef $self->{_meta_instance};
926 my ($self, $attribute_name) = @_;
927 (defined $attribute_name && $attribute_name)
928 || confess "You must define an attribute name";
929 exists $self->get_attribute_map->{$attribute_name};
933 my ($self, $attribute_name) = @_;
934 (defined $attribute_name && $attribute_name)
935 || confess "You must define an attribute name";
936 return $self->get_attribute_map->{$attribute_name}
938 # this will return undef anyway, so no need ...
939 # if $self->has_attribute($attribute_name);
943 sub remove_attribute {
944 my ($self, $attribute_name) = @_;
945 (defined $attribute_name && $attribute_name)
946 || confess "You must define an attribute name";
947 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
948 return unless defined $removed_attribute;
949 delete $self->get_attribute_map->{$attribute_name};
950 $self->invalidate_meta_instances();
951 $removed_attribute->remove_accessors();
952 $removed_attribute->detach_from_class();
953 return $removed_attribute;
956 sub get_attribute_list {
958 keys %{$self->get_attribute_map};
961 sub get_all_attributes {
962 shift->compute_all_applicable_attributes(@_);
965 sub compute_all_applicable_attributes {
967 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
968 return values %attrs;
971 sub find_attribute_by_name {
972 my ($self, $attr_name) = @_;
973 foreach my $class ($self->linearized_isa) {
974 # fetch the meta-class ...
975 my $meta = $self->initialize($class);
976 return $meta->get_attribute($attr_name)
977 if $meta->has_attribute($attr_name);
982 # check if we can reinitialize
986 # if any local attr is defined
987 return if $self->get_attribute_list;
989 # or any non-declared methods
990 if ( my @methods = values %{ $self->get_method_map } ) {
991 my $metaclass = $self->method_metaclass;
992 foreach my $method ( @methods ) {
993 return if $method->isa("Class::MOP::Method::Generated");
994 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1003 sub is_mutable { 1 }
1004 sub is_immutable { 0 }
1007 # Why I changed this (groditi)
1008 # - One Metaclass may have many Classes through many Metaclass instances
1009 # - One Metaclass should only have one Immutable Transformer instance
1010 # - Each Class may have different Immutabilizing options
1011 # - Therefore each Metaclass instance may have different Immutabilizing options
1012 # - We need to store one Immutable Transformer instance per Metaclass
1013 # - We need to store one set of Immutable Transformer options per Class
1014 # - Upon make_mutable we may delete the Immutabilizing options
1015 # - We could clean the immutable Transformer instance when there is no more
1016 # immutable Classes of that type, but we can also keep it in case
1017 # another class with this same Metaclass becomes immutable. It is a case
1018 # of trading of storing an instance to avoid unnecessary instantiations of
1019 # Immutable Transformers. You may view this as a memory leak, however
1020 # Because we have few Metaclasses, in practice it seems acceptable
1021 # - To allow Immutable Transformers instances to be cleaned up we could weaken
1022 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
1026 my %IMMUTABLE_TRANSFORMERS;
1027 my %IMMUTABLE_OPTIONS;
1029 sub get_immutable_options {
1031 return if $self->is_mutable;
1032 confess "unable to find immutabilizing options"
1033 unless exists $IMMUTABLE_OPTIONS{$self->name};
1034 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1035 delete $options{IMMUTABLE_TRANSFORMER};
1039 sub get_immutable_transformer {
1041 if( $self->is_mutable ){
1042 my $class = ref $self || $self;
1043 return $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer;
1045 confess "unable to find transformer for immutable class"
1046 unless exists $IMMUTABLE_OPTIONS{$self->name};
1047 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1050 sub make_immutable {
1054 my $transformer = $self->get_immutable_transformer;
1055 $transformer->make_metaclass_immutable($self, \%options);
1056 $IMMUTABLE_OPTIONS{$self->name} =
1057 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1059 if( exists $options{debug} && $options{debug} ){
1060 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1061 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1069 return if $self->is_mutable;
1070 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1071 confess "unable to find immutabilizing options" unless ref $options;
1072 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1073 $transformer->make_metaclass_mutable($self, $options);
1078 sub create_immutable_transformer {
1080 my $class = Class::MOP::Immutable->new($self, {
1081 read_only => [qw/superclasses/],
1088 remove_package_symbol
1091 class_precedence_list => 'ARRAY',
1092 linearized_isa => 'ARRAY', # FIXME perl 5.10 memoizes this on its own, no need?
1093 get_all_methods => 'ARRAY',
1094 #get_all_attributes => 'ARRAY', # it's an alias, no need, but maybe in the future
1095 compute_all_applicable_attributes => 'ARRAY',
1096 get_meta_instance => 'SCALAR',
1097 get_method_map => 'SCALAR',
1100 # this is ugly, but so are typeglobs,
1101 # so whattayahgonnadoboutit
1104 add_package_symbol => sub {
1105 my $original = shift;
1106 confess "Cannot add package symbols to an immutable metaclass"
1107 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1108 goto $original->body;
1123 Class::MOP::Class - Class Meta Object
1127 # assuming that class Foo
1128 # has been defined, you can
1130 # use this for introspection ...
1132 # add a method to Foo ...
1133 Foo->meta->add_method('bar' => sub { ... })
1135 # get a list of all the classes searched
1136 # the method dispatcher in the correct order
1137 Foo->meta->class_precedence_list()
1139 # remove a method from Foo
1140 Foo->meta->remove_method('bar');
1142 # or use this to actually create classes ...
1144 Class::MOP::Class->create('Bar' => (
1146 superclasses => [ 'Foo' ],
1148 Class::MOP:::Attribute->new('$bar'),
1149 Class::MOP:::Attribute->new('$baz'),
1152 calculate_bar => sub { ... },
1153 construct_baz => sub { ... }
1159 This is the largest and currently most complex part of the Perl 5
1160 meta-object protocol. It controls the introspection and
1161 manipulation of Perl 5 classes (and it can create them too). The
1162 best way to understand what this module can do, is to read the
1163 documentation for each of it's methods.
1167 =head2 Self Introspection
1173 This will return a B<Class::MOP::Class> instance which is related
1174 to this class. Thereby allowing B<Class::MOP::Class> to actually
1177 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1178 bootstrap this module by installing a number of attribute meta-objects
1179 into it's metaclass. This will allow this class to reap all the benifits
1180 of the MOP when subclassing it.
1184 =head2 Class construction
1186 These methods will handle creating B<Class::MOP::Class> objects,
1187 which can be used to both create new classes, and analyze
1188 pre-existing classes.
1190 This module will internally store references to all the instances
1191 you create with these methods, so that they do not need to be
1192 created any more than nessecary. Basically, they are singletons.
1196 =item B<create ($package_name,
1197 version =E<gt> ?$version,
1198 authority =E<gt> ?$authority,
1199 superclasses =E<gt> ?@superclasses,
1200 methods =E<gt> ?%methods,
1201 attributes =E<gt> ?%attributes)>
1203 This returns a B<Class::MOP::Class> object, bringing the specified
1204 C<$package_name> into existence and adding any of the C<$version>,
1205 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1208 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1209 methods =E<gt> ?%methods,
1210 attributes =E<gt> ?%attributes)>
1212 This will create an anonymous class, it works much like C<create> but
1213 it does not need a C<$package_name>. Instead it will create a suitably
1214 unique package name for you to stash things into.
1216 On very important distinction is that anon classes are destroyed once
1217 the metaclass they are attached to goes out of scope. In the DESTROY
1218 method, the created package will be removed from the symbol table.
1220 It is also worth noting that any instances created with an anon-class
1221 will keep a special reference to the anon-meta which will prevent the
1222 anon-class from going out of scope until all instances of it have also
1223 been destroyed. This however only works for HASH based instance types,
1224 as we use a special reserved slot (C<__MOP__>) to store this.
1226 =item B<initialize ($package_name, %options)>
1228 This initializes and returns returns a B<Class::MOP::Class> object
1229 for a given a C<$package_name>.
1231 =item B<construct_class_instance (%options)>
1233 This will construct an instance of B<Class::MOP::Class>, it is
1234 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1235 to use C<construct_instance> once all the bootstrapping is done. This
1236 method is used internally by C<initialize> and should never be called
1237 from outside of that method really.
1239 =item B<check_metaclass_compatability>
1241 This method is called as the very last thing in the
1242 C<construct_class_instance> method. This will check that the
1243 metaclass you are creating is compatible with the metaclasses of all
1244 your ancestors. For more inforamtion about metaclass compatibility
1245 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1247 =item B<update_package_cache_flag>
1249 This will reset the package cache flag for this particular metaclass
1250 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1251 function. This is very rarely needed from outside of C<Class::MOP::Class>
1252 but in some cases you might want to use it, so it is here.
1254 =item B<reset_package_cache_flag>
1256 Clears the package cache flag to announce to the internals that we need
1257 to rebuild the method map.
1259 =item B<add_meta_instance_dependencies>
1261 Registers this class as dependent on its superclasses.
1263 Only superclasses from which this class inherits attributes will be added.
1265 =item B<remove_meta_instance_depdendencies>
1267 Unregisters this class from its superclasses.
1269 =item B<update_meta_instance_dependencies>
1271 Reregisters if necessary.
1273 =item B<add_dependent_meta_instance> $metaclass
1275 Registers the class as having a meta instance dependent on this class.
1277 =item B<remove_dependent_meta_instance> $metaclass
1279 Remove the class from the list of dependent classes.
1281 =item B<invalidate_meta_instances>
1283 Clears the cached meta instance for this metaclass and all of the registered
1284 classes with dependent meta instances.
1286 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1289 =item B<invalidate_meta_instance>
1291 Used by C<invalidate_meta_instances>.
1295 =head2 Object instance construction and cloning
1297 These methods are B<entirely optional>, it is up to you whether you want
1302 =item B<instance_metaclass>
1304 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1305 for more information on the instance metaclasses.
1307 =item B<get_meta_instance>
1309 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1310 of a new instance of the class.
1312 =item B<create_meta_instance>
1314 Called by C<get_meta_instance> if necessary.
1316 =item B<new_object (%params)>
1318 This is a convience method for creating a new object of the class, and
1319 blessing it into the appropriate package as well. Ideally your class
1320 would call a C<new> this method like so:
1323 my ($class, %param) = @_;
1324 $class->meta->new_object(%params);
1327 =item B<construct_instance (%params)>
1329 This method is used to construct an instance structure suitable for
1330 C<bless>-ing into your package of choice. It works in conjunction
1331 with the Attribute protocol to collect all applicable attributes.
1333 This will construct and instance using a HASH ref as storage
1334 (currently only HASH references are supported). This will collect all
1335 the applicable attributes and layout out the fields in the HASH ref,
1336 it will then initialize them using either use the corresponding key
1337 in C<%params> or any default value or initializer found in the
1338 attribute meta-object.
1340 =item B<clone_object ($instance, %params)>
1342 This is a convience method for cloning an object instance, then
1343 blessing it into the appropriate package. This method will call
1344 C<clone_instance>, which performs a shallow copy of the object,
1345 see that methods documentation for more details. Ideally your
1346 class would call a C<clone> this method like so:
1348 sub MyClass::clone {
1349 my ($self, %param) = @_;
1350 $self->meta->clone_object($self, %params);
1353 =item B<clone_instance($instance, %params)>
1355 This method is a compliment of C<construct_instance> (which means if
1356 you override C<construct_instance>, you need to override this one too),
1357 and clones the instance shallowly.
1359 The cloned structure returned is (like with C<construct_instance>) an
1360 unC<bless>ed HASH reference, it is your responsibility to then bless
1361 this cloned structure into the right class (which C<clone_object> will
1364 As of 0.11, this method will clone the C<$instance> structure shallowly,
1365 as opposed to the deep cloning implemented in prior versions. After much
1366 thought, research and discussion, I have decided that anything but basic
1367 shallow cloning is outside the scope of the meta-object protocol. I
1368 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1369 is too I<context-specific> to be part of the MOP.
1371 =item B<rebless_instance($instance, ?%params)>
1373 This will change the class of C<$instance> to the class of the invoking
1374 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1375 itself. You may pass in optional C<%params> which are like constructor
1376 params and will override anything already defined in the instance.
1380 =head2 Informational
1382 These are a few predicate methods for asking information about the class.
1386 =item B<is_anon_class>
1388 This returns true if the class is a C<Class::MOP::Class> created anon class.
1392 This returns true if the class is still mutable.
1394 =item B<is_immutable>
1396 This returns true if the class has been made immutable.
1398 =item B<is_pristine>
1400 Checks whether the class has any data that will be lost if C<reinitialize> is
1405 =head2 Inheritance Relationships
1409 =item B<superclasses (?@superclasses)>
1411 This is a read-write attribute which represents the superclass
1412 relationships of the class the B<Class::MOP::Class> instance is
1413 associated with. Basically, it can get and set the C<@ISA> for you.
1415 =item B<class_precedence_list>
1417 This computes the a list of all the class's ancestors in the same order
1418 in which method dispatch will be done. This is similair to what
1419 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1421 =item B<linearized_isa>
1423 This returns a list based on C<class_precedence_list> but with all
1428 This returns a list of subclasses for this class.
1436 =item B<get_method_map>
1438 Returns a HASH ref of name to CODE reference mapping for this class.
1440 =item B<method_metaclass>
1442 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1443 for more information on the method metaclasses.
1445 =item B<add_method ($method_name, $method)>
1447 This will take a C<$method_name> and CODE reference to that
1448 C<$method> and install it into the class's package.
1451 This does absolutely nothing special to C<$method>
1452 other than use B<Sub::Name> to make sure it is tagged with the
1453 correct name, and therefore show up correctly in stack traces and
1456 =item B<alias_method ($method_name, $method)>
1458 This will take a C<$method_name> and CODE reference to that
1459 C<$method> and alias the method into the class's package.
1462 Unlike C<add_method>, this will B<not> try to name the
1463 C<$method> using B<Sub::Name>, it only aliases the method in
1464 the class's package.
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.
1555 =head2 Method Modifiers
1557 Method modifiers are a concept borrowed from CLOS, in which a method
1558 can be wrapped with I<before>, I<after> and I<around> method modifiers
1559 that will be called everytime the method is called.
1561 =head3 How method modifiers work?
1563 Method modifiers work by wrapping the original method and then replacing
1564 it in the classes symbol table. The wrappers will handle calling all the
1565 modifiers in the appropariate orders and preserving the calling context
1566 for the original method.
1568 Each method modifier serves a particular purpose, which may not be
1569 obvious to users of other method wrapping modules. To start with, the
1570 return values of I<before> and I<after> modifiers are ignored. This is
1571 because thier purpose is B<not> to filter the input and output of the
1572 primary method (this is done with an I<around> modifier). This may seem
1573 like an odd restriction to some, but doing this allows for simple code
1574 to be added at the begining or end of a method call without jeapordizing
1575 the normal functioning of the primary method or placing any extra
1576 responsibility on the code of the modifier. Of course if you have more
1577 complex needs, then use the I<around> modifier, which uses a variation
1578 of continutation passing style to allow for a high degree of flexibility.
1580 Before and around modifiers are called in last-defined-first-called order,
1581 while after modifiers are called in first-defined-first-called order. So
1582 the call tree might looks something like this:
1592 To see examples of using method modifiers, see the following examples
1593 included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
1594 F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
1595 classic CLOS usage example in the test F<017_add_method_modifier.t>.
1597 =head3 What is the performance impact?
1599 Of course there is a performance cost associated with method modifiers,
1600 but we have made every effort to make that cost be directly proportional
1601 to the amount of modifier features you utilize.
1603 The wrapping method does it's best to B<only> do as much work as it
1604 absolutely needs to. In order to do this we have moved some of the
1605 performance costs to set-up time, where they are easier to amortize.
1607 All this said, my benchmarks have indicated the following:
1609 simple wrapper with no modifiers 100% slower
1610 simple wrapper with simple before modifier 400% slower
1611 simple wrapper with simple after modifier 450% slower
1612 simple wrapper with simple around modifier 500-550% slower
1613 simple wrapper with all 3 modifiers 1100% slower
1615 These numbers may seem daunting, but you must remember, every feature
1616 comes with some cost. To put things in perspective, just doing a simple
1617 C<AUTOLOAD> which does nothing but extract the name of the method called
1618 and return it costs about 400% over a normal method call.
1622 =item B<add_before_method_modifier ($method_name, $code)>
1624 This will wrap the method at C<$method_name> and the supplied C<$code>
1625 will be passed the C<@_> arguments, and called before the original
1626 method is called. As specified above, the return value of the I<before>
1627 method modifiers is ignored, and it's ability to modify C<@_> is
1628 fairly limited. If you need to do either of these things, use an
1629 C<around> method modifier.
1631 =item B<add_after_method_modifier ($method_name, $code)>
1633 This will wrap the method at C<$method_name> so that the original
1634 method will be called, it's return values stashed, and then the
1635 supplied C<$code> will be passed the C<@_> arguments, and called.
1636 As specified above, the return value of the I<after> method
1637 modifiers is ignored, and it cannot modify the return values of
1638 the original method. If you need to do either of these things, use an
1639 C<around> method modifier.
1641 =item B<add_around_method_modifier ($method_name, $code)>
1643 This will wrap the method at C<$method_name> so that C<$code>
1644 will be called and passed the original method as an extra argument
1645 at the begining of the C<@_> argument list. This is a variation of
1646 continuation passing style, where the function prepended to C<@_>
1647 can be considered a continuation. It is up to C<$code> if it calls
1648 the original method or not, there is no restriction on what the
1649 C<$code> can or cannot do.
1655 It should be noted that since there is no one consistent way to define
1656 the attributes of a class in Perl 5. These methods can only work with
1657 the information given, and can not easily discover information on
1658 their own. See L<Class::MOP::Attribute> for more details.
1662 =item B<attribute_metaclass>
1664 Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute>
1665 for more information on the attribute metaclasses.
1667 =item B<get_attribute_map>
1669 This returns a HASH ref of name to attribute meta-object mapping.
1671 =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))>
1673 This stores the C<$attribute_meta_object> (or creates one from the
1674 C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class>
1675 instance associated with the given class. Unlike methods, attributes
1676 within the MOP are stored as meta-information only. They will be used
1677 later to construct instances from (see C<construct_instance> above).
1678 More details about the attribute meta-objects can be found in the
1679 L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol>
1682 It should be noted that any accessor, reader/writer or predicate
1683 methods which the C<$attribute_meta_object> has will be installed
1684 into the class at this time.
1687 If an attribute already exists for C<$attribute_name>, the old one
1688 will be removed (as well as removing all it's accessors), and then
1691 =item B<has_attribute ($attribute_name)>
1693 Checks to see if this class has an attribute by the name of
1694 C<$attribute_name> and returns a boolean.
1696 =item B<get_attribute ($attribute_name)>
1698 Returns the attribute meta-object associated with C<$attribute_name>,
1699 if none is found, it will return undef.
1701 =item B<remove_attribute ($attribute_name)>
1703 This will remove the attribute meta-object stored at
1704 C<$attribute_name>, then return the removed attribute meta-object.
1707 Removing an attribute will only affect future instances of
1708 the class, it will not make any attempt to remove the attribute from
1709 any existing instances of the class.
1711 It should be noted that any accessor, reader/writer or predicate
1712 methods which the attribute meta-object stored at C<$attribute_name>
1713 has will be removed from the class at this time. This B<will> make
1714 these attributes somewhat inaccessable in previously created
1715 instances. But if you are crazy enough to do this at runtime, then
1716 you are crazy enough to deal with something like this :).
1718 =item B<get_attribute_list>
1720 This returns a list of attribute names which are defined in the local
1721 class. If you want a list of all applicable attributes for a class,
1722 use the C<compute_all_applicable_attributes> method.
1724 =item B<compute_all_applicable_attributes>
1726 =item B<get_all_attributes>
1728 This will traverse the inheritance heirachy and return a list of all
1729 the applicable L<Class::MOP::Attribute> objects for this class.
1731 C<get_all_attributes> is an alias for consistency with C<get_all_methods>.
1733 =item B<find_attribute_by_name ($attr_name)>
1735 This method will traverse the inheritance heirachy and find the
1736 first attribute whose name matches C<$attr_name>, then return it.
1737 It will return undef if nothing is found.
1741 =head2 Class Immutability
1745 =item B<make_immutable (%options)>
1747 This method will invoke a tranforamtion upon the class which will
1748 make it immutable. Details of this transformation can be found in
1749 the L<Class::MOP::Immutable> documentation.
1751 =item B<make_mutable>
1753 This method will reverse tranforamtion upon the class which
1756 =item B<get_immutable_transformer>
1758 Return a transformer suitable for making this class immutable or, if this
1759 class is immutable, the transformer used to make it immutable.
1761 =item B<get_immutable_options>
1763 If the class is immutable, return the options used to make it immutable.
1765 =item B<create_immutable_transformer>
1767 Create a transformer suitable for making this class immutable
1773 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1775 =head1 COPYRIGHT AND LICENSE
1777 Copyright 2006-2008 by Infinity Interactive, Inc.
1779 L<http://www.iinteractive.com>
1781 This library is free software; you can redistribute it and/or modify
1782 it under the same terms as Perl itself.