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';
22 my ( $class, @args ) = @_;
24 unshift @args, 'package' if @args % 2 == 1;
26 my (%options) = @args;
27 my $package_name = $options{package};
29 (defined $package_name && $package_name && !blessed($package_name))
30 || confess "You must pass a package name and it cannot be blessed";
32 return Class::MOP::get_metaclass_by_name($package_name)
33 || $class->construct_class_instance(%options);
38 my $package_name = shift;
39 (defined $package_name && $package_name && !blessed($package_name))
40 || confess "You must pass a package name and it cannot be blessed";
41 Class::MOP::remove_metaclass_by_name($package_name);
42 $class->construct_class_instance('package' => $package_name, @_);
45 # NOTE: (meta-circularity)
46 # this is a special form of &construct_instance
47 # (see below), which is used to construct class
48 # meta-object instances for any Class::MOP::*
49 # class. All other classes will use the more
50 # normal &construct_instance.
51 sub construct_class_instance {
54 my $package_name = $options{'package'};
55 (defined $package_name && $package_name)
56 || confess "You must pass a package name";
58 # return the metaclass if we have it cached,
59 # and it is still defined (it has not been
60 # reaped by DESTROY yet, which can happen
61 # annoyingly enough during global destruction)
63 if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) {
68 # we need to deal with the possibility
69 # of class immutability here, and then
70 # get the name of the class appropriately
71 $class = (blessed($class)
72 ? ($class->is_immutable
73 ? $class->get_mutable_metaclass_name()
77 # now create the metaclass
79 if ($class eq 'Class::MOP::Class') {
82 # inherited from Class::MOP::Package
83 'package' => $package_name,
86 # since the following attributes will
87 # actually be loaded from the symbol
88 # table, and actually bypass the instance
89 # entirely, we can just leave these things
90 # listed here for reference, because they
91 # should not actually have a value associated
93 'namespace' => \undef,
94 # inherited from Class::MOP::Module
96 'authority' => \undef,
97 # defined in Class::MOP::Class
98 'superclasses' => \undef,
102 'attribute_metaclass' => $options{'attribute_metaclass'} || 'Class::MOP::Attribute',
103 'method_metaclass' => $options{'method_metaclass'} || 'Class::MOP::Method',
104 'instance_metaclass' => $options{'instance_metaclass'} || 'Class::MOP::Instance',
106 ## uber-private variables
108 # this starts out as undef so that
109 # we can tell the first time the
110 # methods are fetched
112 '_package_cache_flag' => undef,
113 '_meta_instance' => undef,
118 # it is safe to use meta here because
119 # class will always be a subclass of
120 # Class::MOP::Class, which defines meta
121 $meta = $class->meta->construct_instance(%options)
124 # and check the metaclass compatibility
125 $meta->check_metaclass_compatability();
127 Class::MOP::store_metaclass_by_name($package_name, $meta);
130 # we need to weaken any anon classes
131 # so that they can call DESTROY properly
132 Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class;
137 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
138 sub update_package_cache_flag {
141 # we can manually update the cache number
142 # since we are actually adding the method
143 # to our cache as well. This avoids us
144 # having to regenerate the method_map.
146 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
149 sub check_metaclass_compatability {
152 # this is always okay ...
153 return if blessed($self) eq 'Class::MOP::Class' &&
154 $self->instance_metaclass eq 'Class::MOP::Instance';
156 my @class_list = $self->linearized_isa;
157 shift @class_list; # shift off $self->name
159 foreach my $class_name (@class_list) {
160 my $meta = Class::MOP::get_metaclass_by_name($class_name) || next;
163 # we need to deal with the possibility
164 # of class immutability here, and then
165 # get the name of the class appropriately
166 my $meta_type = ($meta->is_immutable
167 ? $meta->get_mutable_metaclass_name()
170 ($self->isa($meta_type))
171 || confess $self->name . "->meta => (" . (blessed($self)) . ")" .
172 " is not compatible with the " .
173 $class_name . "->meta => (" . ($meta_type) . ")";
175 # we also need to check that instance metaclasses
176 # are compatabile in the same the class.
177 ($self->instance_metaclass->isa($meta->instance_metaclass))
178 || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" .
179 " is not compatible with the " .
180 $class_name . "->meta => (" . ($meta->instance_metaclass) . ")";
188 # this should be sufficient, if you have a
189 # use case where it is not, write a test and
191 my $ANON_CLASS_SERIAL = 0;
194 # we need a sufficiently annoying prefix
195 # this should suffice for now, this is
196 # used in a couple of places below, so
197 # need to put it up here for now.
198 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
202 no warnings 'uninitialized';
203 $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0;
206 sub create_anon_class {
207 my ($class, %options) = @_;
208 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
209 return $class->create($package_name, %options);
215 require Devel::GlobalDestruction;
216 Devel::GlobalDestruction->import("in_global_destruction");
218 } or *in_global_destruction = sub () { '' };
222 # this will only get called for
223 # anon-classes, all other calls
224 # are assumed to occur during
225 # global destruction and so don't
226 # really need to be handled explicitly
230 return if in_global_destruction; # it'll happen soon anyway and this just makes things more complicated
232 no warnings 'uninitialized';
233 return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
234 my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
236 foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
237 delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
239 delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
244 # creating classes with MOP ...
247 my ( $class, @args ) = @_;
249 unshift @args, 'package' if @args % 2 == 1;
251 my (%options) = @args;
252 my $package_name = $options{package};
254 (defined $package_name && $package_name)
255 || confess "You must pass a package name";
257 (ref $options{superclasses} eq 'ARRAY')
258 || confess "You must pass an ARRAY ref of superclasses"
259 if exists $options{superclasses};
261 (ref $options{attributes} eq 'ARRAY')
262 || confess "You must pass an ARRAY ref of attributes"
263 if exists $options{attributes};
265 (ref $options{methods} eq 'HASH')
266 || confess "You must pass an HASH ref of methods"
267 if exists $options{methods};
269 my $code = "package $package_name;";
270 $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';"
271 if exists $options{version};
272 $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';"
273 if exists $options{authority};
276 confess "creation of $package_name failed : $@" if $@;
278 my $meta = $class->initialize($package_name);
281 $meta->add_method('meta' => sub {
282 $class->initialize(blessed($_[0]) || $_[0]);
285 $meta->superclasses(@{$options{superclasses}})
286 if exists $options{superclasses};
288 # process attributes first, so that they can
289 # install accessors, but locally defined methods
290 # can then overwrite them. It is maybe a little odd, but
291 # I think this should be the order of things.
292 if (exists $options{attributes}) {
293 foreach my $attr (@{$options{attributes}}) {
294 $meta->add_attribute($attr);
297 if (exists $options{methods}) {
298 foreach my $method_name (keys %{$options{methods}}) {
299 $meta->add_method($method_name, $options{methods}->{$method_name});
308 # all these attribute readers will be bootstrapped
309 # away in the Class::MOP bootstrap section
311 sub get_attribute_map { $_[0]->{'attributes'} }
312 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
313 sub method_metaclass { $_[0]->{'method_metaclass'} }
314 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
317 # this is a prime canidate for conversion to XS
321 if (defined $self->{'_package_cache_flag'} &&
322 $self->{'_package_cache_flag'} == Class::MOP::check_package_cache_flag($self->name)) {
323 return $self->{'methods'};
326 my $map = $self->{'methods'};
328 my $class_name = $self->name;
329 my $method_metaclass = $self->method_metaclass;
331 my %all_code = $self->get_all_package_symbols('CODE');
333 foreach my $symbol (keys %all_code) {
334 my $code = $all_code{$symbol};
336 next if exists $map->{$symbol} &&
337 defined $map->{$symbol} &&
338 $map->{$symbol}->body == $code;
340 my ($pkg, $name) = Class::MOP::get_code_info($code);
343 # in 5.10 constant.pm the constants show up
344 # as being in the right package, but in pre-5.10
345 # they show up as constant::__ANON__ so we
346 # make an exception here to be sure that things
347 # work as expected in both.
349 unless ($pkg eq 'constant' && $name eq '__ANON__') {
350 next if ($pkg || '') ne $class_name ||
351 (($name || '') ne '__ANON__' && ($pkg || '') ne $class_name);
354 $map->{$symbol} = $method_metaclass->wrap(
356 package_name => $class_name,
364 # Instance Construction & Cloning
370 # we need to protect the integrity of the
371 # Class::MOP::Class singletons here, so we
372 # delegate this to &construct_class_instance
373 # which will deal with the singletons
374 return $class->construct_class_instance(@_)
375 if $class->name->isa('Class::MOP::Class');
376 return $class->construct_instance(@_);
379 sub construct_instance {
380 my ($class, %params) = @_;
381 my $meta_instance = $class->get_meta_instance();
382 my $instance = $meta_instance->create_instance();
383 foreach my $attr ($class->compute_all_applicable_attributes()) {
384 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
387 # this will only work for a HASH instance type
388 if ($class->is_anon_class) {
389 (Scalar::Util::reftype($instance) eq 'HASH')
390 || confess "Currently only HASH based instances are supported with instance of anon-classes";
392 # At some point we should make this official
393 # as a reserved slot name, but right now I am
394 # going to keep it here.
395 # my $RESERVED_MOP_SLOT = '__MOP__';
396 $instance->{'__MOP__'} = $class;
402 sub get_meta_instance {
404 $self->{'_meta_instance'} ||= $self->create_meta_instance();
407 sub create_meta_instance {
410 my $instance = $self->instance_metaclass->new(
411 associated_metaclass => $self,
412 attributes => [ $self->compute_all_applicable_attributes() ],
415 $self->add_meta_instance_dependencies()
416 if $instance->is_dependent_on_superclasses();
423 my $instance = shift;
424 (blessed($instance) && $instance->isa($class->name))
425 || confess "You must pass an instance of the metaclass (" . $class->name . "), not ($instance)";
428 # we need to protect the integrity of the
429 # Class::MOP::Class singletons here, they
430 # should not be cloned.
431 return $instance if $instance->isa('Class::MOP::Class');
432 $class->clone_instance($instance, @_);
436 my ($class, $instance, %params) = @_;
438 || confess "You can only clone instances, ($instance) is not a blessed instance";
439 my $meta_instance = $class->get_meta_instance();
440 my $clone = $meta_instance->clone_instance($instance);
441 foreach my $attr ($class->compute_all_applicable_attributes()) {
442 if ( defined( my $init_arg = $attr->init_arg ) ) {
443 if (exists $params{$init_arg}) {
444 $attr->set_value($clone, $params{$init_arg});
451 sub rebless_instance {
452 my ($self, $instance, %params) = @_;
455 if ($instance->can('meta')) {
456 ($instance->meta->isa('Class::MOP::Class'))
457 || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class';
458 $old_metaclass = $instance->meta;
461 $old_metaclass = $self->initialize(blessed($instance));
464 my $meta_instance = $self->get_meta_instance();
466 $self->name->isa($old_metaclass->name)
467 || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't.";
470 $meta_instance->rebless_instance_structure($instance, $self);
472 foreach my $attr ( $self->compute_all_applicable_attributes ) {
473 if ( $attr->has_value($instance) ) {
474 if ( defined( my $init_arg = $attr->init_arg ) ) {
475 $params{$init_arg} = $attr->get_value($instance)
476 unless exists $params{$init_arg};
479 $attr->set_value($instance, $attr->get_value($instance));
484 foreach my $attr ($self->compute_all_applicable_attributes) {
485 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
495 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
498 @{$self->get_package_symbol($var_spec)} = @supers;
500 # we need to check the metaclass
501 # compatibility here so that we can
502 # be sure that the superclass is
503 # not potentially creating an issues
504 # we don't know about
505 $self->check_metaclass_compatability();
506 $self->update_meta_instance_dependencies();
508 @{$self->get_package_symbol($var_spec)};
514 my $super_class = $self->name;
516 if ( Class::MOP::HAVE_ISAREV() ) {
517 return @{ $super_class->mro::get_isarev() };
521 my $find_derived_classes;
522 $find_derived_classes = sub {
523 my ($outer_class) = @_;
525 my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} };
528 for my $symbol ( keys %$symbol_table_hashref ) {
529 next SYMBOL if $symbol !~ /\A (\w+):: \z/x;
530 my $inner_class = $1;
532 next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER'
536 ? "${outer_class}::$inner_class"
539 if ( $class->isa($super_class) and $class ne $super_class ) {
540 push @derived_classes, $class;
543 next SYMBOL if $class eq 'main'; # skip 'main::*'
545 $find_derived_classes->($class);
549 my $root_class = q{};
550 $find_derived_classes->($root_class);
552 undef $find_derived_classes;
554 @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes;
556 return @derived_classes;
562 return @{ mro::get_linear_isa( (shift)->name ) };
565 sub class_precedence_list {
567 my $name = $self->name;
569 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
571 # We need to check for circular inheritance here
572 # if we are are not on 5.10, cause 5.8 detects it
573 # late. This will do nothing if all is well, and
574 # blow up otherwise. Yes, it's an ugly hack, better
575 # suggestions are welcome.
577 ($name || return)->isa('This is a test for circular inheritance')
580 # if our mro is c3, we can
581 # just grab the linear_isa
582 if (mro::get_mro($name) eq 'c3') {
583 return @{ mro::get_linear_isa($name) }
587 # we can't grab the linear_isa for dfs
588 # since it has all the duplicates
593 $self->initialize($_)->class_precedence_list()
594 } $self->superclasses()
602 my ($self, $method_name, $method) = @_;
603 (defined $method_name && $method_name)
604 || confess "You must define a method name";
607 if (blessed($method)) {
608 $body = $method->body;
609 if ($method->package_name ne $self->name &&
610 $method->name ne $method_name) {
611 warn "Hello there, got something for you."
612 . " Method says " . $method->package_name . " " . $method->name
613 . " Class says " . $self->name . " " . $method_name;
614 $method = $method->clone(
615 package_name => $self->name,
617 ) if $method->can('clone');
622 ('CODE' eq ref($body))
623 || confess "Your code block must be a CODE reference";
624 $method = $self->method_metaclass->wrap(
626 package_name => $self->name,
631 $self->get_method_map->{$method_name} = $method;
633 my $full_method_name = ($self->name . '::' . $method_name);
634 $self->add_package_symbol(
635 { sigil => '&', type => 'CODE', name => $method_name },
636 Class::MOP::subname($full_method_name => $body)
638 $self->update_package_cache_flag;
642 my $fetch_and_prepare_method = sub {
643 my ($self, $method_name) = @_;
645 my $method = $self->get_method($method_name);
646 # if we dont have local ...
648 # try to find the next method
649 $method = $self->find_next_method_by_name($method_name);
650 # die if it does not exist
652 || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name;
653 # and now make sure to wrap it
654 # even if it is already wrapped
655 # because we need a new sub ref
656 $method = Class::MOP::Method::Wrapped->wrap($method);
659 # now make sure we wrap it properly
660 $method = Class::MOP::Method::Wrapped->wrap($method)
661 unless $method->isa('Class::MOP::Method::Wrapped');
663 $self->add_method($method_name => $method);
667 sub add_before_method_modifier {
668 my ($self, $method_name, $method_modifier) = @_;
669 (defined $method_name && $method_name)
670 || confess "You must pass in a method name";
671 my $method = $fetch_and_prepare_method->($self, $method_name);
672 $method->add_before_modifier(
673 Class::MOP::subname(':before' => $method_modifier)
677 sub add_after_method_modifier {
678 my ($self, $method_name, $method_modifier) = @_;
679 (defined $method_name && $method_name)
680 || confess "You must pass in a method name";
681 my $method = $fetch_and_prepare_method->($self, $method_name);
682 $method->add_after_modifier(
683 Class::MOP::subname(':after' => $method_modifier)
687 sub add_around_method_modifier {
688 my ($self, $method_name, $method_modifier) = @_;
689 (defined $method_name && $method_name)
690 || confess "You must pass in a method name";
691 my $method = $fetch_and_prepare_method->($self, $method_name);
692 $method->add_around_modifier(
693 Class::MOP::subname(':around' => $method_modifier)
698 # the methods above used to be named like this:
699 # ${pkg}::${method}:(before|after|around)
700 # but this proved problematic when using one modifier
701 # to wrap multiple methods (something which is likely
702 # to happen pretty regularly IMO). So instead of naming
703 # it like this, I have chosen to just name them purely
704 # with their modifier names, like so:
705 # :(before|after|around)
706 # The fact is that in a stack trace, it will be fairly
707 # evident from the context what method they are attached
708 # to, and so don't need the fully qualified name.
712 my ($self, $method_name, $method) = @_;
713 (defined $method_name && $method_name)
714 || confess "You must define a method name";
716 my $body = (blessed($method) ? $method->body : $method);
717 ('CODE' eq ref($body))
718 || confess "Your code block must be a CODE reference";
720 $self->add_package_symbol(
721 { sigil => '&', type => 'CODE', name => $method_name } => $body
723 $self->update_package_cache_flag;
727 my ($self, $method_name) = @_;
728 (defined $method_name && $method_name)
729 || confess "You must define a method name";
731 return 0 unless exists $self->get_method_map->{$method_name};
736 my ($self, $method_name) = @_;
737 (defined $method_name && $method_name)
738 || confess "You must define a method name";
741 # I don't really need this here, because
742 # if the method_map is missing a key it
743 # will just return undef for me now
744 # return unless $self->has_method($method_name);
746 return $self->get_method_map->{$method_name};
750 my ($self, $method_name) = @_;
751 (defined $method_name && $method_name)
752 || confess "You must define a method name";
754 my $removed_method = delete $self->get_method_map->{$method_name};
756 $self->remove_package_symbol(
757 { sigil => '&', type => 'CODE', name => $method_name }
760 $self->update_package_cache_flag;
762 return $removed_method;
765 sub get_method_list {
767 keys %{$self->get_method_map};
770 sub find_method_by_name {
771 my ($self, $method_name) = @_;
772 (defined $method_name && $method_name)
773 || confess "You must define a method name to find";
774 foreach my $class ($self->linearized_isa) {
775 # fetch the meta-class ...
776 my $meta = $self->initialize($class);
777 return $meta->get_method($method_name)
778 if $meta->has_method($method_name);
783 sub compute_all_applicable_methods {
785 my (@methods, %seen_method);
786 foreach my $class ($self->linearized_isa) {
787 # fetch the meta-class ...
788 my $meta = $self->initialize($class);
789 foreach my $method_name ($meta->get_method_list()) {
790 next if exists $seen_method{$method_name};
791 $seen_method{$method_name}++;
793 name => $method_name,
795 code => $meta->get_method($method_name)
802 sub find_all_methods_by_name {
803 my ($self, $method_name) = @_;
804 (defined $method_name && $method_name)
805 || confess "You must define a method name to find";
807 foreach my $class ($self->linearized_isa) {
808 # fetch the meta-class ...
809 my $meta = $self->initialize($class);
811 name => $method_name,
813 code => $meta->get_method($method_name)
814 } if $meta->has_method($method_name);
819 sub find_next_method_by_name {
820 my ($self, $method_name) = @_;
821 (defined $method_name && $method_name)
822 || confess "You must define a method name to find";
823 my @cpl = $self->linearized_isa;
824 shift @cpl; # discard ourselves
825 foreach my $class (@cpl) {
826 # fetch the meta-class ...
827 my $meta = $self->initialize($class);
828 return $meta->get_method($method_name)
829 if $meta->has_method($method_name);
838 # either we have an attribute object already
839 # or we need to create one from the args provided
840 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
841 # make sure it is derived from the correct type though
842 ($attribute->isa('Class::MOP::Attribute'))
843 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
845 # first we attach our new attribute
846 # because it might need certain information
847 # about the class which it is attached to
848 $attribute->attach_to_class($self);
850 # then we remove attributes of a conflicting
851 # name here so that we can properly detach
852 # the old attr object, and remove any
853 # accessors it would have generated
854 if ( $self->has_attribute($attribute->name) ) {
855 $self->remove_attribute($attribute->name);
857 $self->invalidate_meta_instances();
860 # then onto installing the new accessors
861 $self->get_attribute_map->{$attribute->name} = $attribute;
863 # invalidate package flag here
864 my $e = do { local $@; eval { $attribute->install_accessors() }; $@ };
866 $self->remove_attribute($attribute->name);
873 sub update_meta_instance_dependencies {
876 if ( $self->{meta_instance_dependencies} ) {
877 return $self->add_meta_instance_dependencies;
881 sub add_meta_instance_dependencies {
884 $self->remove_meta_instance_depdendencies;
886 my @attrs = $self->compute_all_applicable_attributes();
889 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
891 foreach my $class ( @classes ) {
892 $class->add_dependent_meta_instance($self);
895 $self->{meta_instance_dependencies} = \@classes;
898 sub remove_meta_instance_depdendencies {
901 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
902 foreach my $class ( @$classes ) {
903 $class->remove_dependent_meta_instance($self);
913 sub add_dependent_meta_instance {
914 my ( $self, $metaclass ) = @_;
915 push @{ $self->{dependent_meta_instances} }, $metaclass;
918 sub remove_dependent_meta_instance {
919 my ( $self, $metaclass ) = @_;
920 my $name = $metaclass->name;
921 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
924 sub invalidate_meta_instances {
926 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
929 sub invalidate_meta_instance {
931 undef $self->{_meta_instance};
935 my ($self, $attribute_name) = @_;
936 (defined $attribute_name && $attribute_name)
937 || confess "You must define an attribute name";
938 exists $self->get_attribute_map->{$attribute_name} ? 1 : 0;
942 my ($self, $attribute_name) = @_;
943 (defined $attribute_name && $attribute_name)
944 || confess "You must define an attribute name";
945 return $self->get_attribute_map->{$attribute_name}
947 # this will return undef anyway, so no need ...
948 # if $self->has_attribute($attribute_name);
952 sub remove_attribute {
953 my ($self, $attribute_name) = @_;
954 (defined $attribute_name && $attribute_name)
955 || confess "You must define an attribute name";
956 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
957 return unless defined $removed_attribute;
958 delete $self->get_attribute_map->{$attribute_name};
959 $self->invalidate_meta_instances();
960 $removed_attribute->remove_accessors();
961 $removed_attribute->detach_from_class();
962 return $removed_attribute;
965 sub get_attribute_list {
967 keys %{$self->get_attribute_map};
970 sub compute_all_applicable_attributes {
972 my (@attrs, %seen_attr);
973 foreach my $class ($self->linearized_isa) {
974 # fetch the meta-class ...
975 my $meta = $self->initialize($class);
976 foreach my $attr_name ($meta->get_attribute_list()) {
977 next if exists $seen_attr{$attr_name};
978 $seen_attr{$attr_name}++;
979 push @attrs => $meta->get_attribute($attr_name);
985 sub find_attribute_by_name {
986 my ($self, $attr_name) = @_;
987 foreach my $class ($self->linearized_isa) {
988 # fetch the meta-class ...
989 my $meta = $self->initialize($class);
990 return $meta->get_attribute($attr_name)
991 if $meta->has_attribute($attr_name);
999 sub is_immutable { 0 }
1002 # Why I changed this (groditi)
1003 # - One Metaclass may have many Classes through many Metaclass instances
1004 # - One Metaclass should only have one Immutable Transformer instance
1005 # - Each Class may have different Immutabilizing options
1006 # - Therefore each Metaclass instance may have different Immutabilizing options
1007 # - We need to store one Immutable Transformer instance per Metaclass
1008 # - We need to store one set of Immutable Transformer options per Class
1009 # - Upon make_mutable we may delete the Immutabilizing options
1010 # - We could clean the immutable Transformer instance when there is no more
1011 # immutable Classes of that type, but we can also keep it in case
1012 # another class with this same Metaclass becomes immutable. It is a case
1013 # of trading of storing an instance to avoid unnecessary instantiations of
1014 # Immutable Transformers. You may view this as a memory leak, however
1015 # Because we have few Metaclasses, in practice it seems acceptable
1016 # - To allow Immutable Transformers instances to be cleaned up we could weaken
1017 # the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM
1021 my %IMMUTABLE_TRANSFORMERS;
1022 my %IMMUTABLE_OPTIONS;
1024 sub get_immutable_options {
1026 return if $self->is_mutable;
1027 confess "unable to find immutabilizing options"
1028 unless exists $IMMUTABLE_OPTIONS{$self->name};
1029 my %options = %{$IMMUTABLE_OPTIONS{$self->name}};
1030 delete $options{IMMUTABLE_TRANSFORMER};
1034 sub get_immutable_transformer {
1036 if( $self->is_mutable ){
1037 my $class = blessed $self || $self;
1038 return $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer;
1040 confess "unable to find transformer for immutable class"
1041 unless exists $IMMUTABLE_OPTIONS{$self->name};
1042 return $IMMUTABLE_OPTIONS{$self->name}->{IMMUTABLE_TRANSFORMER};
1045 sub make_immutable {
1049 my $transformer = $self->get_immutable_transformer;
1050 $transformer->make_metaclass_immutable($self, \%options);
1051 $IMMUTABLE_OPTIONS{$self->name} =
1052 { %options, IMMUTABLE_TRANSFORMER => $transformer };
1054 if( exists $options{debug} && $options{debug} ){
1055 print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS;
1056 print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS;
1064 return if $self->is_mutable;
1065 my $options = delete $IMMUTABLE_OPTIONS{$self->name};
1066 confess "unable to find immutabilizing options" unless ref $options;
1067 my $transformer = delete $options->{IMMUTABLE_TRANSFORMER};
1068 $transformer->make_metaclass_mutable($self, $options);
1073 sub create_immutable_transformer {
1075 my $class = Class::MOP::Immutable->new($self, {
1076 read_only => [qw/superclasses/],
1083 remove_package_symbol
1086 class_precedence_list => 'ARRAY',
1087 linearized_isa => 'ARRAY',
1088 compute_all_applicable_attributes => 'ARRAY',
1089 get_meta_instance => 'SCALAR',
1090 get_method_map => 'SCALAR',
1093 # this is ugly, but so are typeglobs,
1094 # so whattayahgonnadoboutit
1097 add_package_symbol => sub {
1098 my $original = shift;
1099 confess "Cannot add package symbols to an immutable metaclass"
1100 unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol';
1101 goto $original->body;
1116 Class::MOP::Class - Class Meta Object
1120 # assuming that class Foo
1121 # has been defined, you can
1123 # use this for introspection ...
1125 # add a method to Foo ...
1126 Foo->meta->add_method('bar' => sub { ... })
1128 # get a list of all the classes searched
1129 # the method dispatcher in the correct order
1130 Foo->meta->class_precedence_list()
1132 # remove a method from Foo
1133 Foo->meta->remove_method('bar');
1135 # or use this to actually create classes ...
1137 Class::MOP::Class->create('Bar' => (
1139 superclasses => [ 'Foo' ],
1141 Class::MOP:::Attribute->new('$bar'),
1142 Class::MOP:::Attribute->new('$baz'),
1145 calculate_bar => sub { ... },
1146 construct_baz => sub { ... }
1152 This is the largest and currently most complex part of the Perl 5
1153 meta-object protocol. It controls the introspection and
1154 manipulation of Perl 5 classes (and it can create them too). The
1155 best way to understand what this module can do, is to read the
1156 documentation for each of it's methods.
1160 =head2 Self Introspection
1166 This will return a B<Class::MOP::Class> instance which is related
1167 to this class. Thereby allowing B<Class::MOP::Class> to actually
1170 As with B<Class::MOP::Attribute>, B<Class::MOP> will actually
1171 bootstrap this module by installing a number of attribute meta-objects
1172 into it's metaclass. This will allow this class to reap all the benifits
1173 of the MOP when subclassing it.
1177 =head2 Class construction
1179 These methods will handle creating B<Class::MOP::Class> objects,
1180 which can be used to both create new classes, and analyze
1181 pre-existing classes.
1183 This module will internally store references to all the instances
1184 you create with these methods, so that they do not need to be
1185 created any more than nessecary. Basically, they are singletons.
1189 =item B<create ($package_name,
1190 version =E<gt> ?$version,
1191 authority =E<gt> ?$authority,
1192 superclasses =E<gt> ?@superclasses,
1193 methods =E<gt> ?%methods,
1194 attributes =E<gt> ?%attributes)>
1196 This returns a B<Class::MOP::Class> object, bringing the specified
1197 C<$package_name> into existence and adding any of the C<$version>,
1198 C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
1201 =item B<create_anon_class (superclasses =E<gt> ?@superclasses,
1202 methods =E<gt> ?%methods,
1203 attributes =E<gt> ?%attributes)>
1205 This will create an anonymous class, it works much like C<create> but
1206 it does not need a C<$package_name>. Instead it will create a suitably
1207 unique package name for you to stash things into.
1209 On very important distinction is that anon classes are destroyed once
1210 the metaclass they are attached to goes out of scope. In the DESTROY
1211 method, the created package will be removed from the symbol table.
1213 It is also worth noting that any instances created with an anon-class
1214 will keep a special reference to the anon-meta which will prevent the
1215 anon-class from going out of scope until all instances of it have also
1216 been destroyed. This however only works for HASH based instance types,
1217 as we use a special reserved slot (C<__MOP__>) to store this.
1219 =item B<initialize ($package_name, %options)>
1221 This initializes and returns returns a B<Class::MOP::Class> object
1222 for a given a C<$package_name>.
1224 =item B<reinitialize ($package_name, %options)>
1226 This removes the old metaclass, and creates a new one in it's place.
1227 Do B<not> use this unless you really know what you are doing, it could
1228 very easily make a very large mess of your program.
1230 =item B<construct_class_instance (%options)>
1232 This will construct an instance of B<Class::MOP::Class>, it is
1233 here so that we can actually "tie the knot" for B<Class::MOP::Class>
1234 to use C<construct_instance> once all the bootstrapping is done. This
1235 method is used internally by C<initialize> and should never be called
1236 from outside of that method really.
1238 =item B<check_metaclass_compatability>
1240 This method is called as the very last thing in the
1241 C<construct_class_instance> method. This will check that the
1242 metaclass you are creating is compatible with the metaclasses of all
1243 your ancestors. For more inforamtion about metaclass compatibility
1244 see the C<About Metaclass compatibility> section in L<Class::MOP>.
1246 =item B<update_package_cache_flag>
1248 This will reset the package cache flag for this particular metaclass
1249 it is basically the value of the C<Class::MOP::get_package_cache_flag>
1250 function. This is very rarely needed from outside of C<Class::MOP::Class>
1251 but in some cases you might want to use it, so it is here.
1253 =item B<reset_package_cache_flag>
1255 Clears the package cache flag to announce to the internals that we need
1256 to rebuild the method map.
1258 =item B<add_meta_instance_dependencies>
1260 Registers this class as dependent on its superclasses.
1262 Only superclasses from which this class inherits attributes will be added.
1264 =item B<remove_meta_instance_depdendencies>
1266 Unregisters this class from its superclasses.
1268 =item B<update_meta_instance_dependencies>
1270 Reregisters if necessary.
1272 =item B<add_dependent_meta_instance> $metaclass
1274 Registers the class as having a meta instance dependent on this class.
1276 =item B<remove_dependent_meta_instance> $metaclass
1278 Remove the class from the list of dependent classes.
1280 =item B<invalidate_meta_instances>
1282 Clears the cached meta instance for this metaclass and all of the registered
1283 classes with dependent meta instances.
1285 Called by C<add_attribute> and C<remove_attribute> to recalculate the attribute
1288 =item B<invalidate_meta_instance>
1290 Used by C<invalidate_meta_instances>.
1294 =head2 Object instance construction and cloning
1296 These methods are B<entirely optional>, it is up to you whether you want
1301 =item B<instance_metaclass>
1303 Returns the class name of the instance metaclass, see L<Class::MOP::Instance>
1304 for more information on the instance metaclasses.
1306 =item B<get_meta_instance>
1308 Returns an instance of L<Class::MOP::Instance> to be used in the construction
1309 of a new instance of the class.
1311 =item B<create_meta_instance>
1313 Called by C<get_meta_instance> if necessary.
1315 =item B<new_object (%params)>
1317 This is a convience method for creating a new object of the class, and
1318 blessing it into the appropriate package as well. Ideally your class
1319 would call a C<new> this method like so:
1322 my ($class, %param) = @_;
1323 $class->meta->new_object(%params);
1326 =item B<construct_instance (%params)>
1328 This method is used to construct an instance structure suitable for
1329 C<bless>-ing into your package of choice. It works in conjunction
1330 with the Attribute protocol to collect all applicable attributes.
1332 This will construct and instance using a HASH ref as storage
1333 (currently only HASH references are supported). This will collect all
1334 the applicable attributes and layout out the fields in the HASH ref,
1335 it will then initialize them using either use the corresponding key
1336 in C<%params> or any default value or initializer found in the
1337 attribute meta-object.
1339 =item B<clone_object ($instance, %params)>
1341 This is a convience method for cloning an object instance, then
1342 blessing it into the appropriate package. This method will call
1343 C<clone_instance>, which performs a shallow copy of the object,
1344 see that methods documentation for more details. Ideally your
1345 class would call a C<clone> this method like so:
1347 sub MyClass::clone {
1348 my ($self, %param) = @_;
1349 $self->meta->clone_object($self, %params);
1352 =item B<clone_instance($instance, %params)>
1354 This method is a compliment of C<construct_instance> (which means if
1355 you override C<construct_instance>, you need to override this one too),
1356 and clones the instance shallowly.
1358 The cloned structure returned is (like with C<construct_instance>) an
1359 unC<bless>ed HASH reference, it is your responsibility to then bless
1360 this cloned structure into the right class (which C<clone_object> will
1363 As of 0.11, this method will clone the C<$instance> structure shallowly,
1364 as opposed to the deep cloning implemented in prior versions. After much
1365 thought, research and discussion, I have decided that anything but basic
1366 shallow cloning is outside the scope of the meta-object protocol. I
1367 think Yuval "nothingmuch" Kogman put it best when he said that cloning
1368 is too I<context-specific> to be part of the MOP.
1370 =item B<rebless_instance($instance, ?%params)>
1372 This will change the class of C<$instance> to the class of the invoking
1373 C<Class::MOP::Class>. You may only rebless the instance to a subclass of
1374 itself. You may pass in optional C<%params> which are like constructor
1375 params and will override anything already defined in the instance.
1379 =head2 Informational
1381 These are a few predicate methods for asking information about the class.
1385 =item B<is_anon_class>
1387 This returns true if the class is a C<Class::MOP::Class> created anon class.
1391 This returns true if the class is still mutable.
1393 =item B<is_immutable>
1395 This returns true if the class has been made immutable.
1399 =head2 Inheritance Relationships
1403 =item B<superclasses (?@superclasses)>
1405 This is a read-write attribute which represents the superclass
1406 relationships of the class the B<Class::MOP::Class> instance is
1407 associated with. Basically, it can get and set the C<@ISA> for you.
1409 =item B<class_precedence_list>
1411 This computes the a list of all the class's ancestors in the same order
1412 in which method dispatch will be done. This is similair to what
1413 B<Class::ISA::super_path> does, but we don't remove duplicate names.
1415 =item B<linearized_isa>
1417 This returns a list based on C<class_precedence_list> but with all
1422 This returns a list of subclasses for this class.
1430 =item B<get_method_map>
1432 Returns a HASH ref of name to CODE reference mapping for this class.
1434 =item B<method_metaclass>
1436 Returns the class name of the method metaclass, see L<Class::MOP::Method>
1437 for more information on the method metaclasses.
1439 =item B<add_method ($method_name, $method)>
1441 This will take a C<$method_name> and CODE reference to that
1442 C<$method> and install it into the class's package.
1445 This does absolutely nothing special to C<$method>
1446 other than use B<Sub::Name> to make sure it is tagged with the
1447 correct name, and therefore show up correctly in stack traces and
1450 =item B<alias_method ($method_name, $method)>
1452 This will take a C<$method_name> and CODE reference to that
1453 C<$method> and alias the method into the class's package.
1456 Unlike C<add_method>, this will B<not> try to name the
1457 C<$method> using B<Sub::Name>, it only aliases the method in
1458 the class's package.
1460 =item B<has_method ($method_name)>
1462 This just provides a simple way to check if the class implements
1463 a specific C<$method_name>. It will I<not> however, attempt to check
1464 if the class inherits the method (use C<UNIVERSAL::can> for that).
1466 This will correctly handle functions defined outside of the package
1467 that use a fully qualified name (C<sub Package::name { ... }>).
1469 This will correctly handle functions renamed with B<Sub::Name> and
1470 installed using the symbol tables. However, if you are naming the
1471 subroutine outside of the package scope, you must use the fully
1472 qualified name, including the package name, for C<has_method> to
1473 correctly identify it.
1475 This will attempt to correctly ignore functions imported from other
1476 packages using B<Exporter>. It breaks down if the function imported
1477 is an C<__ANON__> sub (such as with C<use constant>), which very well
1478 may be a valid method being applied to the class.
1480 In short, this method cannot always be trusted to determine if the
1481 C<$method_name> is actually a method. However, it will DWIM about
1482 90% of the time, so it's a small trade off I think.
1484 =item B<get_method ($method_name)>
1486 This will return a Class::MOP::Method instance related to the specified
1487 C<$method_name>, or return undef if that method does not exist.
1489 The Class::MOP::Method is codifiable, so you can use it like a normal
1490 CODE reference, see L<Class::MOP::Method> for more information.
1492 =item B<find_method_by_name ($method_name)>
1494 This will return a CODE reference of the specified C<$method_name>,
1495 or return undef if that method does not exist.
1497 Unlike C<get_method> this will also look in the superclasses.
1499 =item B<remove_method ($method_name)>
1501 This will attempt to remove a given C<$method_name> from the class.
1502 It will return the CODE reference that it has removed, and will
1503 attempt to use B<Sub::Name> to clear the methods associated name.
1505 =item B<get_method_list>
1507 This will return a list of method names for all I<locally> defined
1508 methods. It does B<not> provide a list of all applicable methods,
1509 including any inherited ones. If you want a list of all applicable
1510 methods, use the C<compute_all_applicable_methods> method.
1512 =item B<compute_all_applicable_methods>
1514 This will return a list of all the methods names this class will
1515 respond to, taking into account inheritance. The list will be a list of
1516 HASH references, each one containing the following information; method
1517 name, the name of the class in which the method lives and a CODE
1518 reference for the actual method.
1520 =item B<find_all_methods_by_name ($method_name)>
1522 This will traverse the inheritence hierarchy and locate all methods
1523 with a given C<$method_name>. Similar to
1524 C<compute_all_applicable_methods> it returns a list of HASH references
1525 with the following information; method name (which will always be the
1526 same as C<$method_name>), the name of the class in which the method
1527 lives and a CODE reference for the actual method.
1529 The list of methods produced is a distinct list, meaning there are no
1530 duplicates in it. This is especially useful for things like object
1531 initialization and destruction where you only want the method called
1532 once, and in the correct order.
1534 =item B<find_next_method_by_name ($method_name)>
1536 This will return the first method to match a given C<$method_name> in
1537 the superclasses, this is basically equivalent to calling
1538 C<SUPER::$method_name>, but it can be dispatched at runtime.
1542 =head2 Method Modifiers
1544 Method modifiers are a concept borrowed from CLOS, in which a method
1545 can be wrapped with I<before>, I<after> and I<around> method modifiers
1546 that will be called everytime the method is called.
1548 =head3 How method modifiers work?
1550 Method modifiers work by wrapping the original method and then replacing
1551 it in the classes symbol table. The wrappers will handle calling all the
1552 modifiers in the appropariate orders and preserving the calling context
1553 for the original method.
1555 Each method modifier serves a particular purpose, which may not be
1556 obvious to users of other method wrapping modules. To start with, the
1557 return values of I<before> and I<after> modifiers are ignored. This is
1558 because thier purpose is B<not> to filter the input and output of the
1559 primary method (this is done with an I<around> modifier). This may seem
1560 like an odd restriction to some, but doing this allows for simple code
1561 to be added at the begining or end of a method call without jeapordizing
1562 the normal functioning of the primary method or placing any extra
1563 responsibility on the code of the modifier. Of course if you have more
1564 complex needs, then use the I<around> modifier, which uses a variation
1565 of continutation passing style to allow for a high degree of flexibility.
1567 Before and around modifiers are called in last-defined-first-called order,
1568 while after modifiers are called in first-defined-first-called order. So
1569 the call tree might looks something like this:
1579 To see examples of using method modifiers, see the following examples
1580 included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
1581 F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
1582 classic CLOS usage example in the test F<017_add_method_modifier.t>.
1584 =head3 What is the performance impact?
1586 Of course there is a performance cost associated with method modifiers,
1587 but we have made every effort to make that cost be directly proportional
1588 to the amount of modifier features you utilize.
1590 The wrapping method does it's best to B<only> do as much work as it
1591 absolutely needs to. In order to do this we have moved some of the
1592 performance costs to set-up time, where they are easier to amortize.
1594 All this said, my benchmarks have indicated the following:
1596 simple wrapper with no modifiers 100% slower
1597 simple wrapper with simple before modifier 400% slower
1598 simple wrapper with simple after modifier 450% slower
1599 simple wrapper with simple around modifier 500-550% slower
1600 simple wrapper with all 3 modifiers 1100% slower
1602 These numbers may seem daunting, but you must remember, every feature
1603 comes with some cost. To put things in perspective, just doing a simple
1604 C<AUTOLOAD> which does nothing but extract the name of the method called
1605 and return it costs about 400% over a normal method call.
1609 =item B<add_before_method_modifier ($method_name, $code)>
1611 This will wrap the method at C<$method_name> and the supplied C<$code>
1612 will be passed the C<@_> arguments, and called before the original
1613 method is called. As specified above, the return value of the I<before>
1614 method modifiers is ignored, and it's ability to modify C<@_> is
1615 fairly limited. If you need to do either of these things, use an
1616 C<around> method modifier.
1618 =item B<add_after_method_modifier ($method_name, $code)>
1620 This will wrap the method at C<$method_name> so that the original
1621 method will be called, it's return values stashed, and then the
1622 supplied C<$code> will be passed the C<@_> arguments, and called.
1623 As specified above, the return value of the I<after> method
1624 modifiers is ignored, and it cannot modify the return values of
1625 the original method. If you need to do either of these things, use an
1626 C<around> method modifier.
1628 =item B<add_around_method_modifier ($method_name, $code)>
1630 This will wrap the method at C<$method_name> so that C<$code>
1631 will be called and passed the original method as an extra argument
1632 at the begining of the C<@_> argument list. This is a variation of
1633 continuation passing style, where the function prepended to C<@_>
1634 can be considered a continuation. It is up to C<$code> if it calls
1635 the original method or not, there is no restriction on what the
1636 C<$code> can or cannot do.
1642 It should be noted that since there is no one consistent way to define
1643 the attributes of a class in Perl 5. These methods can only work with
1644 the information given, and can not easily discover information on
1645 their own. See L<Class::MOP::Attribute> for more details.
1649 =item B<attribute_metaclass>
1651 Returns the class name of the attribute metaclass, see L<Class::MOP::Attribute>
1652 for more information on the attribute metaclasses.
1654 =item B<get_attribute_map>
1656 This returns a HASH ref of name to attribute meta-object mapping.
1658 =item B<add_attribute ($attribute_meta_object | ($attribute_name, %attribute_spec))>
1660 This stores the C<$attribute_meta_object> (or creates one from the
1661 C<$attribute_name> and C<%attribute_spec>) in the B<Class::MOP::Class>
1662 instance associated with the given class. Unlike methods, attributes
1663 within the MOP are stored as meta-information only. They will be used
1664 later to construct instances from (see C<construct_instance> above).
1665 More details about the attribute meta-objects can be found in the
1666 L<Class::MOP::Attribute> or the L<Class::MOP/The Attribute protocol>
1669 It should be noted that any accessor, reader/writer or predicate
1670 methods which the C<$attribute_meta_object> has will be installed
1671 into the class at this time.
1674 If an attribute already exists for C<$attribute_name>, the old one
1675 will be removed (as well as removing all it's accessors), and then
1678 =item B<has_attribute ($attribute_name)>
1680 Checks to see if this class has an attribute by the name of
1681 C<$attribute_name> and returns a boolean.
1683 =item B<get_attribute ($attribute_name)>
1685 Returns the attribute meta-object associated with C<$attribute_name>,
1686 if none is found, it will return undef.
1688 =item B<remove_attribute ($attribute_name)>
1690 This will remove the attribute meta-object stored at
1691 C<$attribute_name>, then return the removed attribute meta-object.
1694 Removing an attribute will only affect future instances of
1695 the class, it will not make any attempt to remove the attribute from
1696 any existing instances of the class.
1698 It should be noted that any accessor, reader/writer or predicate
1699 methods which the attribute meta-object stored at C<$attribute_name>
1700 has will be removed from the class at this time. This B<will> make
1701 these attributes somewhat inaccessable in previously created
1702 instances. But if you are crazy enough to do this at runtime, then
1703 you are crazy enough to deal with something like this :).
1705 =item B<get_attribute_list>
1707 This returns a list of attribute names which are defined in the local
1708 class. If you want a list of all applicable attributes for a class,
1709 use the C<compute_all_applicable_attributes> method.
1711 =item B<compute_all_applicable_attributes>
1713 This will traverse the inheritance heirachy and return a list of all
1714 the applicable attributes for this class. It does not construct a
1715 HASH reference like C<compute_all_applicable_methods> because all
1716 that same information is discoverable through the attribute
1719 =item B<find_attribute_by_name ($attr_name)>
1721 This method will traverse the inheritance heirachy and find the
1722 first attribute whose name matches C<$attr_name>, then return it.
1723 It will return undef if nothing is found.
1727 =head2 Class Immutability
1731 =item B<make_immutable (%options)>
1733 This method will invoke a tranforamtion upon the class which will
1734 make it immutable. Details of this transformation can be found in
1735 the L<Class::MOP::Immutable> documentation.
1737 =item B<make_mutable>
1739 This method will reverse tranforamtion upon the class which
1742 =item B<get_immutable_transformer>
1744 Return a transformer suitable for making this class immutable or, if this
1745 class is immutable, the transformer used to make it immutable.
1747 =item B<get_immutable_options>
1749 If the class is immutable, return the options used to make it immutable.
1751 =item B<create_immutable_transformer>
1753 Create a transformer suitable for making this class immutable
1759 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1761 =head1 COPYRIGHT AND LICENSE
1763 Copyright 2006-2008 by Infinity Interactive, Inc.
1765 L<http://www.iinteractive.com>
1767 This library is free software; you can redistribute it and/or modify
1768 it under the same terms as Perl itself.