2 package Class::MOP::Class;
7 use Class::MOP::Instance;
8 use Class::MOP::Method::Wrapped;
9 use Class::MOP::Method::Accessor;
10 use Class::MOP::Method::Constructor;
13 use Scalar::Util 'blessed', 'weaken';
14 use Sub::Name 'subname';
15 use Devel::GlobalDestruction 'in_global_destruction';
17 our $VERSION = '0.89';
18 $VERSION = eval $VERSION;
19 our $AUTHORITY = 'cpan:STEVAN';
21 use base 'Class::MOP::Module';
31 $package_name = shift;
34 $package_name = $options{package};
37 (defined $package_name && $package_name && !ref($package_name))
38 || confess "You must pass a package name and it cannot be blessed";
40 return Class::MOP::get_metaclass_by_name($package_name)
41 || $class->_construct_class_instance(package => $package_name, @_);
44 sub construct_class_instance {
45 Carp::cluck('The construct_class_instance method has been made private.'
46 . " The public version is deprecated and will be removed in a future release.\n");
47 shift->_construct_class_instance(@_);
50 # NOTE: (meta-circularity)
51 # this is a special form of _construct_instance
52 # (see below), which is used to construct class
53 # meta-object instances for any Class::MOP::*
54 # class. All other classes will use the more
55 # normal &construct_instance.
56 sub _construct_class_instance {
58 my $options = @_ == 1 ? $_[0] : {@_};
59 my $package_name = $options->{package};
60 (defined $package_name && $package_name)
61 || confess "You must pass a package name";
63 # return the metaclass if we have it cached,
64 # and it is still defined (it has not been
65 # reaped by DESTROY yet, which can happen
66 # annoyingly enough during global destruction)
68 if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) {
73 # we need to deal with the possibility
74 # of class immutability here, and then
75 # get the name of the class appropriately
77 ? ($class->is_immutable
78 ? $class->get_mutable_metaclass_name()
82 # now create the metaclass
84 if ($class eq 'Class::MOP::Class') {
85 $meta = $class->_new($options);
89 # it is safe to use meta here because
90 # class will always be a subclass of
91 # Class::MOP::Class, which defines meta
92 $meta = $class->meta->_construct_instance($options)
95 # and check the metaclass compatibility
96 $meta->_check_metaclass_compatibility();
98 Class::MOP::store_metaclass_by_name($package_name, $meta);
101 # we need to weaken any anon classes
102 # so that they can call DESTROY properly
103 Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class;
110 return Class::MOP::Class->initialize($class)->new_object(@_)
111 if $class ne __PACKAGE__;
113 my $options = @_ == 1 ? $_[0] : {@_};
116 # inherited from Class::MOP::Package
117 'package' => $options->{package},
120 # since the following attributes will
121 # actually be loaded from the symbol
122 # table, and actually bypass the instance
123 # entirely, we can just leave these things
124 # listed here for reference, because they
125 # should not actually have a value associated
127 'namespace' => \undef,
129 # inherited from Class::MOP::Module
131 'authority' => \undef,
133 # defined in Class::MOP::Class
134 'superclasses' => \undef,
138 'attribute_metaclass' =>
139 ( $options->{'attribute_metaclass'} || 'Class::MOP::Attribute' ),
140 'method_metaclass' =>
141 ( $options->{'method_metaclass'} || 'Class::MOP::Method' ),
142 'wrapped_method_metaclass' => (
143 $options->{'wrapped_method_metaclass'}
144 || 'Class::MOP::Method::Wrapped'
146 'instance_metaclass' =>
147 ( $options->{'instance_metaclass'} || 'Class::MOP::Instance' ),
148 'immutable_trait' => (
149 $options->{'immutable_trait'}
150 || 'Class::MOP::Class::Immutable::Trait'
152 'constructor_name' => ( $options->{constructor_name} || 'new' ),
153 'constructor_class' => (
154 $options->{constructor_class} || 'Class::MOP::Method::Constructor'
156 'destructor_class' => $options->{destructor_class},
160 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
161 sub update_package_cache_flag {
164 # we can manually update the cache number
165 # since we are actually adding the method
166 # to our cache as well. This avoids us
167 # having to regenerate the method_map.
169 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
173 sub check_metaclass_compatibility {
174 Carp::cluck('The check_metaclass_compatibility method has been made private.'
175 . " The public version is deprecated and will be removed in a future release.\n");
176 shift->_check_metaclass_compatibility(@_);
179 sub _check_metaclass_compatibility {
182 # this is always okay ...
183 return if ref($self) eq 'Class::MOP::Class' &&
184 $self->instance_metaclass eq 'Class::MOP::Instance';
186 my @class_list = $self->linearized_isa;
187 shift @class_list; # shift off $self->name
189 foreach my $superclass_name (@class_list) {
190 my $super_meta = Class::MOP::get_metaclass_by_name($superclass_name) || next;
193 # we need to deal with the possibility
194 # of class immutability here, and then
195 # get the name of the class appropriately
197 = $super_meta->is_immutable
198 ? $super_meta->get_mutable_metaclass_name()
201 ($self->isa($super_meta_type))
202 || confess "The metaclass of " . $self->name . " ("
203 . (ref($self)) . ")" . " is not compatible with the " .
204 "metaclass of its superclass, ".$superclass_name . " ("
205 . ($super_meta_type) . ")";
207 # we also need to check that instance metaclasses
208 # are compatibile in the same the class.
209 ($self->instance_metaclass->isa($super_meta->instance_metaclass))
210 || confess "The instance metaclass for " . $self->name . " (" . ($self->instance_metaclass) . ")" .
211 " is not compatible with the " .
212 "instance metaclass of its superclass, " . $superclass_name . " (" . ($super_meta->instance_metaclass) . ")";
220 # this should be sufficient, if you have a
221 # use case where it is not, write a test and
223 my $ANON_CLASS_SERIAL = 0;
226 # we need a sufficiently annoying prefix
227 # this should suffice for now, this is
228 # used in a couple of places below, so
229 # need to put it up here for now.
230 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
234 no warnings 'uninitialized';
235 $self->name =~ /^$ANON_CLASS_PREFIX/;
238 sub create_anon_class {
239 my ($class, %options) = @_;
240 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
241 return $class->create($package_name, %options);
245 # this will only get called for
246 # anon-classes, all other calls
247 # are assumed to occur during
248 # global destruction and so don't
249 # really need to be handled explicitly
253 return if in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
255 no warnings 'uninitialized';
256 my $name = $self->name;
257 return unless $name =~ /^$ANON_CLASS_PREFIX/;
258 # Moose does a weird thing where it replaces the metaclass for
259 # class when fixing metaclass incompatibility. In that case,
260 # we don't want to clean out the namespace now. We can detect
261 # that because Moose will explicitly update the singleton
262 # cache in Class::MOP.
263 my $current_meta = Class::MOP::get_metaclass_by_name($name);
264 return if $current_meta ne $self;
266 my ($serial_id) = ($name =~ /^$ANON_CLASS_PREFIX(\d+)/);
268 @{$name . '::ISA'} = ();
269 %{$name . '::'} = ();
270 delete ${$ANON_CLASS_PREFIX}{$serial_id . '::'};
272 Class::MOP::remove_metaclass_by_name($name);
277 # creating classes with MOP ...
280 my ( $class, @args ) = @_;
282 unshift @args, 'package' if @args % 2 == 1;
284 my (%options) = @args;
285 my $package_name = $options{package};
287 (ref $options{superclasses} eq 'ARRAY')
288 || confess "You must pass an ARRAY ref of superclasses"
289 if exists $options{superclasses};
291 (ref $options{attributes} eq 'ARRAY')
292 || confess "You must pass an ARRAY ref of attributes"
293 if exists $options{attributes};
295 (ref $options{methods} eq 'HASH')
296 || confess "You must pass a HASH ref of methods"
297 if exists $options{methods};
299 my (%initialize_options) = @args;
300 delete @initialize_options{qw(
308 my $meta = $class->initialize( $package_name => %initialize_options );
310 $meta->_instantiate_module( $options{version}, $options{authority} );
313 $meta->add_method('meta' => sub {
314 $class->initialize(ref($_[0]) || $_[0]);
317 $meta->superclasses(@{$options{superclasses}})
318 if exists $options{superclasses};
320 # process attributes first, so that they can
321 # install accessors, but locally defined methods
322 # can then overwrite them. It is maybe a little odd, but
323 # I think this should be the order of things.
324 if (exists $options{attributes}) {
325 foreach my $attr (@{$options{attributes}}) {
326 $meta->add_attribute($attr);
329 if (exists $options{methods}) {
330 foreach my $method_name (keys %{$options{methods}}) {
331 $meta->add_method($method_name, $options{methods}->{$method_name});
340 # all these attribute readers will be bootstrapped
341 # away in the Class::MOP bootstrap section
343 sub get_attribute_map { $_[0]->{'attributes'} }
344 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
345 sub method_metaclass { $_[0]->{'method_metaclass'} }
346 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
347 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
348 sub immutable_trait { $_[0]->{'immutable_trait'} }
349 sub constructor_class { $_[0]->{'constructor_class'} }
350 sub constructor_name { $_[0]->{'constructor_name'} }
351 sub destructor_class { $_[0]->{'destructor_class'} }
353 # Instance Construction & Cloning
359 # we need to protect the integrity of the
360 # Class::MOP::Class singletons here, so we
361 # delegate this to &construct_class_instance
362 # which will deal with the singletons
363 return $class->_construct_class_instance(@_)
364 if $class->name->isa('Class::MOP::Class');
365 return $class->_construct_instance(@_);
368 sub construct_instance {
369 Carp::cluck('The construct_instance method has been made private.'
370 . " The public version is deprecated and will be removed in a future release.\n");
371 shift->_construct_instance(@_);
374 sub _construct_instance {
376 my $params = @_ == 1 ? $_[0] : {@_};
377 my $meta_instance = $class->get_meta_instance();
379 # the code below is almost certainly incorrect
380 # but this is foreign inheritance, so we might
381 # have to kludge it in the end.
382 my $instance = $params->{__INSTANCE__} || $meta_instance->create_instance();
383 foreach my $attr ($class->get_all_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 {
408 Carp::cluck('The create_meta_instance method has been made private.'
409 . " The public version is deprecated and will be removed in a future release.\n");
410 shift->_create_meta_instance(@_);
413 sub _create_meta_instance {
416 my $instance = $self->instance_metaclass->new(
417 associated_metaclass => $self,
418 attributes => [ $self->get_all_attributes() ],
421 $self->add_meta_instance_dependencies()
422 if $instance->is_dependent_on_superclasses();
429 my $instance = shift;
430 (blessed($instance) && $instance->isa($class->name))
431 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
434 # we need to protect the integrity of the
435 # Class::MOP::Class singletons here, they
436 # should not be cloned.
437 return $instance if $instance->isa('Class::MOP::Class');
438 $class->_clone_instance($instance, @_);
442 Carp::cluck('The clone_instance method has been made private.'
443 . " The public version is deprecated and will be removed in a future release.\n");
444 shift->_clone_instance(@_);
447 sub _clone_instance {
448 my ($class, $instance, %params) = @_;
450 || confess "You can only clone instances, ($instance) is not a blessed instance";
451 my $meta_instance = $class->get_meta_instance();
452 my $clone = $meta_instance->clone_instance($instance);
453 foreach my $attr ($class->get_all_attributes()) {
454 if ( defined( my $init_arg = $attr->init_arg ) ) {
455 if (exists $params{$init_arg}) {
456 $attr->set_value($clone, $params{$init_arg});
463 sub rebless_instance {
464 my ($self, $instance, %params) = @_;
466 my $old_metaclass = Class::MOP::class_of($instance);
468 my $old_class = $old_metaclass ? $old_metaclass->name : blessed($instance);
469 $self->name->isa($old_class)
470 || confess "You may rebless only into a subclass of ($old_class), of which (". $self->name .") isn't.";
472 $old_metaclass->rebless_instance_away($instance, $self, %params)
475 my $meta_instance = $self->get_meta_instance();
478 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
479 $meta_instance->rebless_instance_structure($_[1], $self);
481 foreach my $attr ( $self->get_all_attributes ) {
482 if ( $attr->has_value($instance) ) {
483 if ( defined( my $init_arg = $attr->init_arg ) ) {
484 $params{$init_arg} = $attr->get_value($instance)
485 unless exists $params{$init_arg};
488 $attr->set_value($instance, $attr->get_value($instance));
493 foreach my $attr ($self->get_all_attributes) {
494 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
500 sub rebless_instance_away {
501 # this intentionally does nothing, it is just a hook
508 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
511 @{$self->get_package_symbol($var_spec)} = @supers;
514 # on 5.8 and below, we need to call
515 # a method to get Perl to detect
516 # a cycle in the class hierarchy
517 my $class = $self->name;
521 # we need to check the metaclass
522 # compatibility here so that we can
523 # be sure that the superclass is
524 # not potentially creating an issues
525 # we don't know about
527 $self->_check_metaclass_compatibility();
528 $self->_superclasses_updated();
530 @{$self->get_package_symbol($var_spec)};
533 sub _superclasses_updated {
535 $self->update_meta_instance_dependencies();
540 my $super_class = $self->name;
542 return @{ $super_class->mro::get_isarev() };
545 sub direct_subclasses {
547 my $super_class = $self->name;
552 } Class::MOP::Class->initialize($_)->superclasses
557 return @{ mro::get_linear_isa( (shift)->name ) };
560 sub class_precedence_list {
562 my $name = $self->name;
564 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
566 # We need to check for circular inheritance here
567 # if we are are not on 5.10, cause 5.8 detects it
568 # late. This will do nothing if all is well, and
569 # blow up otherwise. Yes, it's an ugly hack, better
570 # suggestions are welcome.
572 ($name || return)->isa('This is a test for circular inheritance')
575 # if our mro is c3, we can
576 # just grab the linear_isa
577 if (mro::get_mro($name) eq 'c3') {
578 return @{ mro::get_linear_isa($name) }
582 # we can't grab the linear_isa for dfs
583 # since it has all the duplicates
588 $self->initialize($_)->class_precedence_list()
589 } $self->superclasses()
596 sub wrap_method_body {
597 my ( $self, %args ) = @_;
599 ('CODE' eq ref $args{body})
600 || confess "Your code block must be a CODE reference";
602 $self->method_metaclass->wrap(
603 package_name => $self->name,
609 my ($self, $method_name, $method) = @_;
610 (defined $method_name && $method_name)
611 || confess "You must define a method name";
614 if (blessed($method)) {
615 $body = $method->body;
616 if ($method->package_name ne $self->name) {
617 $method = $method->clone(
618 package_name => $self->name,
620 ) if $method->can('clone');
625 $method = $self->wrap_method_body( body => $body, name => $method_name );
628 $method->attach_to_class($self);
630 $self->get_method_map->{$method_name} = $method;
632 my ( $current_package, $current_name ) = Class::MOP::get_code_info($body);
634 if ( !defined $current_name || $current_name eq '__ANON__' ) {
635 my $full_method_name = ($self->name . '::' . $method_name);
636 subname($full_method_name => $body);
639 $self->add_package_symbol(
640 { sigil => '&', type => 'CODE', name => $method_name },
646 my $fetch_and_prepare_method = sub {
647 my ($self, $method_name) = @_;
648 my $wrapped_metaclass = $self->wrapped_method_metaclass;
650 my $method = $self->get_method($method_name);
651 # if we dont have local ...
653 # try to find the next method
654 $method = $self->find_next_method_by_name($method_name);
655 # die if it does not exist
657 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
658 # and now make sure to wrap it
659 # even if it is already wrapped
660 # because we need a new sub ref
661 $method = $wrapped_metaclass->wrap($method);
664 # now make sure we wrap it properly
665 $method = $wrapped_metaclass->wrap($method)
666 unless $method->isa($wrapped_metaclass);
668 $self->add_method($method_name => $method);
672 sub add_before_method_modifier {
673 my ($self, $method_name, $method_modifier) = @_;
674 (defined $method_name && $method_name)
675 || confess "You must pass in a method name";
676 my $method = $fetch_and_prepare_method->($self, $method_name);
677 $method->add_before_modifier(
678 subname(':before' => $method_modifier)
682 sub add_after_method_modifier {
683 my ($self, $method_name, $method_modifier) = @_;
684 (defined $method_name && $method_name)
685 || confess "You must pass in a method name";
686 my $method = $fetch_and_prepare_method->($self, $method_name);
687 $method->add_after_modifier(
688 subname(':after' => $method_modifier)
692 sub add_around_method_modifier {
693 my ($self, $method_name, $method_modifier) = @_;
694 (defined $method_name && $method_name)
695 || confess "You must pass in a method name";
696 my $method = $fetch_and_prepare_method->($self, $method_name);
697 $method->add_around_modifier(
698 subname(':around' => $method_modifier)
703 # the methods above used to be named like this:
704 # ${pkg}::${method}:(before|after|around)
705 # but this proved problematic when using one modifier
706 # to wrap multiple methods (something which is likely
707 # to happen pretty regularly IMO). So instead of naming
708 # it like this, I have chosen to just name them purely
709 # with their modifier names, like so:
710 # :(before|after|around)
711 # The fact is that in a stack trace, it will be fairly
712 # evident from the context what method they are attached
713 # to, and so don't need the fully qualified name.
717 Carp::cluck("The alias_method method is deprecated. Use add_method instead.\n");
719 shift->add_method(@_);
723 my ($self, $method_name) = @_;
724 (defined $method_name && $method_name)
725 || confess "You must define a method name";
727 exists $self->get_method_map->{$method_name};
731 my ($self, $method_name) = @_;
732 (defined $method_name && $method_name)
733 || confess "You must define a method name";
735 return $self->get_method_map->{$method_name};
739 my ($self, $method_name) = @_;
740 (defined $method_name && $method_name)
741 || confess "You must define a method name";
743 my $removed_method = delete $self->get_method_map->{$method_name};
745 $self->remove_package_symbol(
746 { sigil => '&', type => 'CODE', name => $method_name }
749 $removed_method->detach_from_class if $removed_method;
751 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
753 return $removed_method;
756 sub get_method_list {
758 keys %{$self->get_method_map};
761 sub find_method_by_name {
762 my ($self, $method_name) = @_;
763 (defined $method_name && $method_name)
764 || confess "You must define a method name to find";
765 foreach my $class ($self->linearized_isa) {
766 # fetch the meta-class ...
767 my $meta = $self->initialize($class);
768 return $meta->get_method($method_name)
769 if $meta->has_method($method_name);
774 sub get_all_methods {
776 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
777 return values %methods;
780 sub compute_all_applicable_methods {
781 Carp::cluck('The compute_all_applicable_methods method is deprecated.'
782 . " Use get_all_methods instead.\n");
787 class => $_->package_name,
788 code => $_, # sigh, overloading
790 } shift->get_all_methods(@_);
793 sub get_all_method_names {
796 grep { $uniq{$_}++ == 0 } map { $_->name } $self->get_all_methods;
799 sub find_all_methods_by_name {
800 my ($self, $method_name) = @_;
801 (defined $method_name && $method_name)
802 || confess "You must define a method name to find";
804 foreach my $class ($self->linearized_isa) {
805 # fetch the meta-class ...
806 my $meta = $self->initialize($class);
808 name => $method_name,
810 code => $meta->get_method($method_name)
811 } if $meta->has_method($method_name);
816 sub find_next_method_by_name {
817 my ($self, $method_name) = @_;
818 (defined $method_name && $method_name)
819 || confess "You must define a method name to find";
820 my @cpl = $self->linearized_isa;
821 shift @cpl; # discard ourselves
822 foreach my $class (@cpl) {
823 # fetch the meta-class ...
824 my $meta = $self->initialize($class);
825 return $meta->get_method($method_name)
826 if $meta->has_method($method_name);
835 # either we have an attribute object already
836 # or we need to create one from the args provided
837 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
838 # make sure it is derived from the correct type though
839 ($attribute->isa('Class::MOP::Attribute'))
840 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
842 # first we attach our new attribute
843 # because it might need certain information
844 # about the class which it is attached to
845 $attribute->attach_to_class($self);
847 my $attr_name = $attribute->name;
849 # then we remove attributes of a conflicting
850 # name here so that we can properly detach
851 # the old attr object, and remove any
852 # accessors it would have generated
853 if ( $self->has_attribute($attr_name) ) {
854 $self->remove_attribute($attr_name);
856 $self->invalidate_meta_instances();
859 # get our count of previously inserted attributes and
860 # increment by one so this attribute knows its order
861 my $order = (scalar keys %{$self->get_attribute_map});
862 $attribute->_set_insertion_order($order);
864 # then onto installing the new accessors
865 $self->get_attribute_map->{$attr_name} = $attribute;
867 # invalidate package flag here
871 eval { $attribute->install_accessors() };
875 $self->remove_attribute($attr_name);
882 sub update_meta_instance_dependencies {
885 if ( $self->{meta_instance_dependencies} ) {
886 return $self->add_meta_instance_dependencies;
890 sub add_meta_instance_dependencies {
893 $self->remove_meta_instance_dependencies;
895 my @attrs = $self->get_all_attributes();
898 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
900 foreach my $class ( @classes ) {
901 $class->add_dependent_meta_instance($self);
904 $self->{meta_instance_dependencies} = \@classes;
907 sub remove_meta_instance_dependencies {
910 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
911 foreach my $class ( @$classes ) {
912 $class->remove_dependent_meta_instance($self);
922 sub add_dependent_meta_instance {
923 my ( $self, $metaclass ) = @_;
924 push @{ $self->{dependent_meta_instances} }, $metaclass;
927 sub remove_dependent_meta_instance {
928 my ( $self, $metaclass ) = @_;
929 my $name = $metaclass->name;
930 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
933 sub invalidate_meta_instances {
935 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
938 sub invalidate_meta_instance {
940 undef $self->{_meta_instance};
944 my ($self, $attribute_name) = @_;
945 (defined $attribute_name && $attribute_name)
946 || confess "You must define an attribute name";
947 exists $self->get_attribute_map->{$attribute_name};
951 my ($self, $attribute_name) = @_;
952 (defined $attribute_name && $attribute_name)
953 || confess "You must define an attribute name";
954 return $self->get_attribute_map->{$attribute_name}
956 # this will return undef anyway, so no need ...
957 # if $self->has_attribute($attribute_name);
961 sub remove_attribute {
962 my ($self, $attribute_name) = @_;
963 (defined $attribute_name && $attribute_name)
964 || confess "You must define an attribute name";
965 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
966 return unless defined $removed_attribute;
967 delete $self->get_attribute_map->{$attribute_name};
968 $self->invalidate_meta_instances();
969 $removed_attribute->remove_accessors();
970 $removed_attribute->detach_from_class();
971 return $removed_attribute;
974 sub get_attribute_list {
976 keys %{$self->get_attribute_map};
979 sub get_all_attributes {
981 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
982 return values %attrs;
985 sub compute_all_applicable_attributes {
986 Carp::cluck('The compute_all_applicable_attributes method has been deprecated.'
987 . " Use get_all_attributes instead.\n");
989 shift->get_all_attributes(@_);
992 sub find_attribute_by_name {
993 my ($self, $attr_name) = @_;
994 foreach my $class ($self->linearized_isa) {
995 # fetch the meta-class ...
996 my $meta = $self->initialize($class);
997 return $meta->get_attribute($attr_name)
998 if $meta->has_attribute($attr_name);
1003 # check if we can reinitialize
1007 # if any local attr is defined
1008 return if $self->get_attribute_list;
1010 # or any non-declared methods
1011 if ( my @methods = values %{ $self->get_method_map } ) {
1012 my $metaclass = $self->method_metaclass;
1013 foreach my $method ( @methods ) {
1014 return if $method->isa("Class::MOP::Method::Generated");
1015 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1024 sub is_mutable { 1 }
1025 sub is_immutable { 0 }
1027 sub _immutable_options {
1028 my ( $self, @args ) = @_;
1031 inline_accessors => 1,
1032 inline_constructor => 1,
1033 inline_destructor => 0,
1035 immutable_trait => $self->immutable_trait,
1036 constructor_name => $self->constructor_name,
1037 constructor_class => $self->constructor_class,
1038 destructor_class => $self->destructor_class,
1043 sub make_immutable {
1044 my ( $self, @args ) = @_;
1046 if ( $self->is_mutable ) {
1047 $self->_initialize_immutable( $self->_immutable_options(@args) );
1048 $self->_rebless_as_immutable(@args);
1059 if ( $self->is_immutable ) {
1060 my @args = $self->immutable_options;
1061 $self->_rebless_as_mutable();
1062 $self->_remove_inlined_code(@args);
1063 delete $self->{__immutable};
1071 sub _rebless_as_immutable {
1072 my ( $self, @args ) = @_;
1074 $self->{__immutable}{original_class} = ref $self;
1076 bless $self => $self->_immutable_metaclass(@args);
1079 sub _immutable_metaclass {
1080 my ( $self, %args ) = @_;
1082 if ( my $class = $args{immutable_metaclass} ) {
1086 my $trait = $args{immutable_trait} = $self->immutable_trait
1087 || confess "no immutable trait specified for $self";
1089 my $meta_attr = $self->meta->find_attribute_by_name("immutable_trait");
1093 if ( $meta_attr and $trait eq $meta_attr->default ) {
1094 # if the trait is the same as the default we try and pick a
1095 # predictable name for the immutable metaclass
1096 $class_name = 'Class::MOP::Class::Immutable::' . ref($self);
1099 $class_name = join '::', 'Class::MOP::Class::Immutable::CustomTrait',
1100 $trait, 'ForMetaClass', ref($self);
1104 if Class::MOP::is_class_loaded($class_name);
1106 # If the metaclass is a subclass of CMOP::Class which has had
1107 # metaclass roles applied (via Moose), then we want to make sure
1108 # that we preserve that anonymous class (see Fey::ORM for an
1109 # example of where this matters).
1111 = $self->meta->is_immutable
1112 ? $self->meta->get_mutable_metaclass_name
1115 my $meta = $meta_name->create(
1117 superclasses => [ ref $self ],
1120 Class::MOP::load_class($trait);
1121 for my $meth ( Class::MOP::Class->initialize($trait)->get_all_methods ) {
1122 next if $meta->has_method( $meth->name );
1124 if ( $meta->find_method_by_name( $meth->name ) ) {
1125 $meta->add_around_method_modifier( $meth->name, $meth->body );
1128 $meta->add_method( $meth->name, $meth->clone );
1132 $meta->make_immutable( inline_constructor => 0 );
1137 sub _remove_inlined_code {
1140 $self->remove_method( $_->name ) for $self->_inlined_methods;
1142 delete $self->{__immutable}{inlined_methods};
1145 sub _inlined_methods { @{ $_[0]{__immutable}{inlined_methods} || [] } }
1147 sub _add_inlined_method {
1148 my ( $self, $method ) = @_;
1150 push @{ $self->{__immutable}{inlined_methods} ||= [] }, $method;
1153 sub _initialize_immutable {
1154 my ( $self, %args ) = @_;
1156 $self->{__immutable}{options} = \%args;
1157 $self->_install_inlined_code(%args);
1160 sub _install_inlined_code {
1161 my ( $self, %args ) = @_;
1164 $self->_inline_accessors(%args) if $args{inline_accessors};
1165 $self->_inline_constructor(%args) if $args{inline_constructor};
1166 $self->_inline_destructor(%args) if $args{inline_destructor};
1169 sub _rebless_as_mutable {
1172 bless $self, $self->get_mutable_metaclass_name;
1177 sub _inline_accessors {
1180 foreach my $attr_name ( $self->get_attribute_list ) {
1181 $self->get_attribute($attr_name)->install_accessors(1);
1185 sub _inline_constructor {
1186 my ( $self, %args ) = @_;
1188 my $name = $args{constructor_name};
1190 if ( $self->has_method($name) && !$args{replace_constructor} ) {
1191 my $class = $self->name;
1192 warn "Not inlining a constructor for $class since it defines"
1193 . " its own constructor.\n"
1194 . "If you are certain you don't need to inline your"
1195 . " constructor, specify inline_constructor => 0 in your"
1196 . " call to $class->meta->make_immutable\n";
1200 my $constructor_class = $args{constructor_class};
1202 Class::MOP::load_class($constructor_class);
1204 my $constructor = $constructor_class->new(
1208 package_name => $self->name,
1212 if ( $args{replace_constructor} or $constructor->can_be_inlined ) {
1213 $self->add_method( $name => $constructor );
1214 $self->_add_inlined_method($constructor);
1218 sub _inline_destructor {
1219 my ( $self, %args ) = @_;
1221 ( exists $args{destructor_class} && defined $args{destructor_class} )
1222 || confess "The 'inline_destructor' option is present, but "
1223 . "no destructor class was specified";
1225 if ( $self->has_method('DESTROY') && ! $args{replace_destructor} ) {
1226 my $class = $self->name;
1227 warn "Not inlining a destructor for $class since it defines"
1228 . " its own destructor.\n";
1232 my $destructor_class = $args{destructor_class};
1234 Class::MOP::load_class($destructor_class);
1236 return unless $destructor_class->is_needed($self);
1238 my $destructor = $destructor_class->new(
1241 package_name => $self->name,
1245 if ( $args{replace_destructor} or $destructor->can_be_inlined ) {
1246 $self->add_method( 'DESTROY' => $destructor );
1247 $self->_add_inlined_method($destructor);
1259 Class::MOP::Class - Class Meta Object
1263 # assuming that class Foo
1264 # has been defined, you can
1266 # use this for introspection ...
1268 # add a method to Foo ...
1269 Foo->meta->add_method( 'bar' => sub {...} )
1271 # get a list of all the classes searched
1272 # the method dispatcher in the correct order
1273 Foo->meta->class_precedence_list()
1275 # remove a method from Foo
1276 Foo->meta->remove_method('bar');
1278 # or use this to actually create classes ...
1280 Class::MOP::Class->create(
1283 superclasses => ['Foo'],
1285 Class::MOP::Attribute->new('$bar'),
1286 Class::MOP::Attribute->new('$baz'),
1289 calculate_bar => sub {...},
1290 construct_baz => sub {...}
1297 The Class Protocol is the largest and most complex part of the
1298 Class::MOP meta-object protocol. It controls the introspection and
1299 manipulation of Perl 5 classes, and it can create them as well. The
1300 best way to understand what this module can do, is to read the
1301 documentation for each of its methods.
1305 C<Class::MOP::Class> is a subclass of L<Class::MOP::Module>.
1309 =head2 Class construction
1311 These methods all create new C<Class::MOP::Class> objects. These
1312 objects can represent existing classes, or they can be used to create
1313 new classes from scratch.
1315 The metaclass object for a given class is a singleton. If you attempt
1316 to create a metaclass for the same class twice, you will just get the
1321 =item B<< Class::MOP::Class->create($package_name, %options) >>
1323 This method creates a new C<Class::MOP::Class> object with the given
1324 package name. It accepts a number of options.
1330 An optional version number for the newly created package.
1334 An optional authority for the newly created package.
1336 =item * superclasses
1338 An optional array reference of superclass names.
1342 An optional hash reference of methods for the class. The keys of the
1343 hash reference are method names, and values are subroutine references.
1347 An optional array reference of L<Class::MOP::Attribute> objects.
1351 =item B<< Class::MOP::Class->create_anon_class(%options) >>
1353 This method works just like C<< Class::MOP::Class->create >> but it
1354 creates an "anonymous" class. In fact, the class does have a name, but
1355 that name is a unique name generated internally by this module.
1357 It accepts the same C<superclasses>, C<methods>, and C<attributes>
1358 parameters that C<create> accepts.
1360 Anonymous classes are destroyed once the metaclass they are attached
1361 to goes out of scope, and will be removed from Perl's internal symbol
1364 All instances of an anonymous class keep a special reference to the
1365 metaclass object, which prevents the metaclass from going out of scope
1366 while any instances exist.
1368 This only works if the instance if based on a hash reference, however.
1370 =item B<< Class::MOP::Class->initialize($package_name, %options) >>
1372 This method will initialize a C<Class::MOP::Class> object for the
1373 named package. Unlike C<create>, this method I<will not> create a new
1376 The purpose of this method is to retrieve a C<Class::MOP::Class>
1377 object for introspecting an existing class.
1379 If an existing C<Class::MOP::Class> object exists for the named
1380 package, it will be returned, and any options provided will be
1383 If the object does not yet exist, it will be created.
1385 The valid options that can be passed to this method are
1386 C<attribute_metaclass>, C<method_metaclass>,
1387 C<wrapped_method_metaclass>, and C<instance_metaclass>. These are all
1388 optional, and default to the appropriate class in the C<Class::MOP>
1393 =head2 Object instance construction and cloning
1395 These methods are all related to creating and/or cloning object
1400 =item B<< $metaclass->clone_object($instance, %params) >>
1402 This method clones an existing object instance. Any parameters you
1403 provide are will override existing attribute values in the object.
1405 This is a convenience method for cloning an object instance, then
1406 blessing it into the appropriate package.
1408 You could implement a clone method in your class, using this method:
1411 my ($self, %params) = @_;
1412 $self->meta->clone_object($self, %params);
1415 =item B<< $metaclass->rebless_instance($instance, %params) >>
1417 This method changes the class of C<$instance> to the metaclass's class.
1419 You can only rebless an instance into a subclass of its current
1420 class. If you pass any additional parameters, these will be treated
1421 like constructor parameters and used to initialize the object's
1422 attributes. Any existing attributes that are already set will be
1425 Before reblessing the instance, this method will call
1426 C<rebless_instance_away> on the instance's current metaclass. This method
1427 will be passed the instance, the new metaclass, and any parameters
1428 specified to C<rebless_instance>. By default, C<rebless_instance_away>
1429 does nothing; it is merely a hook.
1431 =item B<< $metaclass->new_object(%params) >>
1433 This method is used to create a new object of the metaclass's
1434 class. Any parameters you provide are used to initialize the
1435 instance's attributes. A special C<__INSTANCE__> key can be passed to
1436 provide an already generated instance, rather than having Class::MOP
1437 generate it for you. This is mostly useful for using Class::MOP with
1438 foreign classes, which generally generate instances using their own
1441 =item B<< $metaclass->instance_metaclass >>
1443 Returns the class name of the instance metaclass, see
1444 L<Class::MOP::Instance> for more information on the instance
1447 =item B<< $metaclass->get_meta_instance >>
1449 Returns an instance of the C<instance_metaclass> to be used in the
1450 construction of a new instance of the class.
1454 =head2 Informational predicates
1456 These are a few predicate methods for asking information about the
1461 =item B<< $metaclass->is_anon_class >>
1463 This returns true if the class was created by calling C<<
1464 Class::MOP::Class->create_anon_class >>.
1466 =item B<< $metaclass->is_mutable >>
1468 This returns true if the class is still mutable.
1470 =item B<< $metaclass->is_immutable >>
1472 This returns true if the class has been made immutable.
1474 =item B<< $metaclass->is_pristine >>
1476 A class is I<not> pristine if it has non-inherited attributes or if it
1477 has any generated methods.
1481 =head2 Inheritance Relationships
1485 =item B<< $metaclass->superclasses(@superclasses) >>
1487 This is a read-write accessor which represents the superclass
1488 relationships of the metaclass's class.
1490 This is basically sugar around getting and setting C<@ISA>.
1492 =item B<< $metaclass->class_precedence_list >>
1494 This returns a list of all of the class's ancestor classes. The
1495 classes are returned in method dispatch order.
1497 =item B<< $metaclass->linearized_isa >>
1499 This returns a list based on C<class_precedence_list> but with all
1502 =item B<< $metaclass->subclasses >>
1504 This returns a list of all subclasses for this class, even indirect
1507 =item B<< $metaclass->direct_subclasses >>
1509 This returns a list of immediate subclasses for this class, which does not
1510 include indirect subclasses.
1514 =head2 Method introspection and creation
1516 These methods allow you to introspect a class's methods, as well as
1517 add, remove, or change methods.
1519 Determining what is truly a method in a Perl 5 class requires some
1520 heuristics (aka guessing).
1522 Methods defined outside the package with a fully qualified name (C<sub
1523 Package::name { ... }>) will be included. Similarly, methods named
1524 with a fully qualified name using L<Sub::Name> are also included.
1526 However, we attempt to ignore imported functions.
1528 Ultimately, we are using heuristics to determine what truly is a
1529 method in a class, and these heuristics may get the wrong answer in
1530 some edge cases. However, for most "normal" cases the heuristics work
1535 =item B<< $metaclass->get_method($method_name) >>
1537 This will return a L<Class::MOP::Method> for the specified
1538 C<$method_name>. If the class does not have the specified method, it
1541 =item B<< $metaclass->has_method($method_name) >>
1543 Returns a boolean indicating whether or not the class defines the
1544 named method. It does not include methods inherited from parent
1547 =item B<< $metaclass->get_method_map >>
1549 Returns a hash reference representing the methods defined in this
1550 class. The keys are method names and the values are
1551 L<Class::MOP::Method> objects.
1553 =item B<< $metaclass->get_method_list >>
1555 This will return a list of method I<names> for all methods defined in
1558 =item B<< $metaclass->get_all_methods >>
1560 This will traverse the inheritance hierarchy and return a list of all
1561 the L<Class::MOP::Method> objects for this class and its parents.
1563 =item B<< $metaclass->find_method_by_name($method_name) >>
1565 This will return a L<Class::MOP::Method> for the specified
1566 C<$method_name>. If the class does not have the specified method, it
1569 Unlike C<get_method>, this method I<will> look for the named method in
1572 =item B<< $metaclass->get_all_method_names >>
1574 This will return a list of method I<names> for all of this class's
1575 methods, including inherited methods.
1577 =item B<< $metaclass->find_all_methods_by_name($method_name) >>
1579 This method looks for the named method in the class and all of its
1580 parents. It returns every matching method it finds in the inheritance
1581 tree, so it returns a list of methods.
1583 Each method is returned as a hash reference with three keys. The keys
1584 are C<name>, C<class>, and C<code>. The C<code> key has a
1585 L<Class::MOP::Method> object as its value.
1587 The list of methods is distinct.
1589 =item B<< $metaclass->find_next_method_by_name($method_name) >>
1591 This method returns the first method in any superclass matching the
1592 given name. It is effectively the method that C<SUPER::$method_name>
1595 =item B<< $metaclass->add_method($method_name, $method) >>
1597 This method takes a method name and a subroutine reference, and adds
1598 the method to the class.
1600 The subroutine reference can be a L<Class::MOP::Method>, and you are
1601 strongly encouraged to pass a meta method object instead of a code
1602 reference. If you do so, that object gets stored as part of the
1603 class's method map directly. If not, the meta information will have to
1604 be recreated later, and may be incorrect.
1606 If you provide a method object, this method will clone that object if
1607 the object's package name does not match the class name. This lets us
1608 track the original source of any methods added from other classes
1609 (notably Moose roles).
1611 =item B<< $metaclass->remove_method($method_name) >>
1613 Remove the named method from the class. This method returns the
1614 L<Class::MOP::Method> object for the method.
1616 =item B<< $metaclass->method_metaclass >>
1618 Returns the class name of the method metaclass, see
1619 L<Class::MOP::Method> for more information on the method metaclass.
1621 =item B<< $metaclass->wrapped_method_metaclass >>
1623 Returns the class name of the wrapped method metaclass, see
1624 L<Class::MOP::Method::Wrapped> for more information on the wrapped
1629 =head2 Attribute introspection and creation
1631 Because Perl 5 does not have a core concept of attributes in classes,
1632 we can only return information about attributes which have been added
1633 via this class's methods. We cannot discover information about
1634 attributes which are defined in terms of "regular" Perl 5 methods.
1638 =item B<< $metaclass->get_attribute($attribute_name) >>
1640 This will return a L<Class::MOP::Attribute> for the specified
1641 C<$attribute_name>. If the class does not have the specified
1642 attribute, it returns C<undef>.
1644 NOTE that get_attribute does not search superclasses, for that you
1645 need to use C<find_attribute_by_name>.
1647 =item B<< $metaclass->has_attribute($attribute_name) >>
1649 Returns a boolean indicating whether or not the class defines the
1650 named attribute. It does not include attributes inherited from parent
1653 =item B<< $metaclass->get_attribute_map >>
1655 Returns a hash reference representing the attributes defined in this
1656 class. The keys are attribute names and the values are
1657 L<Class::MOP::Attribute> objects.
1659 =item B<< $metaclass->get_attribute_list >>
1661 This will return a list of attributes I<names> for all attributes
1662 defined in this class.
1664 =item B<< $metaclass->get_all_attributes >>
1666 This will traverse the inheritance hierarchy and return a list of all
1667 the L<Class::MOP::Attribute> objects for this class and its parents.
1669 =item B<< $metaclass->find_attribute_by_name($attribute_name) >>
1671 This will return a L<Class::MOP::Attribute> for the specified
1672 C<$attribute_name>. If the class does not have the specified
1673 attribute, it returns C<undef>
1675 Unlike C<get_attribute>, this attribute I<will> look for the named
1676 attribute in superclasses.
1678 =item B<< $metaclass->add_attribute(...) >>
1680 This method accepts either an existing L<Class::MOP::Attribute>
1681 object, or parameters suitable for passing to that class's C<new>
1684 The attribute provided will be added to the class.
1686 Any accessor methods defined by the attribute will be added to the
1687 class when the attribute is added.
1689 If an attribute of the same name already exists, the old attribute
1690 will be removed first.
1692 =item B<< $metaclass->remove_attribute($attribute_name) >>
1694 This will remove the named attribute from the class, and
1695 L<Class::MOP::Attribute> object.
1697 Removing an attribute also removes any accessor methods defined by the
1700 However, note that removing an attribute will only affect I<future>
1701 object instances created for this class, not existing instances.
1703 =item B<< $metaclass->attribute_metaclass >>
1705 Returns the class name of the attribute metaclass for this class. By
1706 default, this is L<Class::MOP::Attribute>. for more information on
1710 =head2 Class Immutability
1712 Making a class immutable "freezes" the class definition. You can no
1713 longer call methods which alter the class, such as adding or removing
1714 methods or attributes.
1716 Making a class immutable lets us optimize the class by inlining some
1717 methods, and also allows us to optimize some methods on the metaclass
1720 After immutabilization, the metaclass object will cache most
1721 informational methods such as C<get_method_map> and
1722 C<get_all_attributes>. Methods which would alter the class, such as
1723 C<add_attribute>, C<add_method>, and so on will throw an error on an
1724 immutable metaclass object.
1726 The immutabilization system in L<Moose> takes much greater advantage
1727 of the inlining features than Class::MOP itself does.
1731 =item B<< $metaclass->make_immutable(%options) >>
1733 This method will create an immutable transformer and uses it to make
1734 the class and its metaclass object immutable.
1736 This method accepts the following options:
1740 =item * inline_accessors
1742 =item * inline_constructor
1744 =item * inline_destructor
1746 These are all booleans indicating whether the specified method(s)
1749 By default, accessors and the constructor are inlined, but not the
1752 =item * immutable_trait
1754 The name of a class which will be used as a parent class for the
1755 metaclass object being made immutable. This "trait" implements the
1756 post-immutability functionality of the metaclass (but not the
1757 transformation itself).
1759 This defaults to L<Class::MOP::Class::Immutable::Trait>.
1761 =item * constructor_name
1763 This is the constructor method name. This defaults to "new".
1765 =item * constructor_class
1767 The name of the method metaclass for constructors. It will be used to
1768 generate the inlined constructor. This defaults to
1769 "Class::MOP::Method::Constructor".
1771 =item * replace_constructor
1773 This is a boolean indicating whether an existing constructor should be
1774 replaced when inlining a constructor. This defaults to false.
1776 =item * destructor_class
1778 The name of the method metaclass for destructors. It will be used to
1779 generate the inlined destructor. This defaults to
1780 "Class::MOP::Method::Denstructor".
1782 =item * replace_destructor
1784 This is a boolean indicating whether an existing destructor should be
1785 replaced when inlining a destructor. This defaults to false.
1789 =item B<< $metaclass->make_mutable >>
1791 Calling this method reverse the immutabilization transformation.
1795 =head2 Method Modifiers
1797 Method modifiers are hooks which allow a method to be wrapped with
1798 I<before>, I<after> and I<around> method modifiers. Every time a
1799 method is called, it's modifiers are also called.
1801 A class can modify its own methods, as well as methods defined in
1804 =head3 How method modifiers work?
1806 Method modifiers work by wrapping the original method and then
1807 replacing it in the class's symbol table. The wrappers will handle
1808 calling all the modifiers in the appropriate order and preserving the
1809 calling context for the original method.
1811 The return values of C<before> and C<after> modifiers are
1812 ignored. This is because their purpose is B<not> to filter the input
1813 and output of the primary method (this is done with an I<around>
1816 This may seem like an odd restriction to some, but doing this allows
1817 for simple code to be added at the beginning or end of a method call
1818 without altering the function of the wrapped method or placing any
1819 extra responsibility on the code of the modifier.
1821 Of course if you have more complex needs, you can use the C<around>
1822 modifier which allows you to change both the parameters passed to the
1823 wrapped method, as well as its return value.
1825 Before and around modifiers are called in last-defined-first-called
1826 order, while after modifiers are called in first-defined-first-called
1827 order. So the call tree might looks something like this:
1839 =head3 What is the performance impact?
1841 Of course there is a performance cost associated with method
1842 modifiers, but we have made every effort to make that cost directly
1843 proportional to the number of modifier features you utilize.
1845 The wrapping method does it's best to B<only> do as much work as it
1846 absolutely needs to. In order to do this we have moved some of the
1847 performance costs to set-up time, where they are easier to amortize.
1849 All this said, our benchmarks have indicated the following:
1851 simple wrapper with no modifiers 100% slower
1852 simple wrapper with simple before modifier 400% slower
1853 simple wrapper with simple after modifier 450% slower
1854 simple wrapper with simple around modifier 500-550% slower
1855 simple wrapper with all 3 modifiers 1100% slower
1857 These numbers may seem daunting, but you must remember, every feature
1858 comes with some cost. To put things in perspective, just doing a
1859 simple C<AUTOLOAD> which does nothing but extract the name of the
1860 method called and return it costs about 400% over a normal method
1865 =item B<< $metaclass->add_before_method_modifier($method_name, $code) >>
1867 This wraps the specified method with the supplied subroutine
1868 reference. The modifier will be called as a method itself, and will
1869 receive the same arguments as are passed to the method.
1871 When the modifier exits, the wrapped method will be called.
1873 The return value of the modifier will be ignored.
1875 =item B<< $metaclass->add_after_method_modifier($method_name, $code) >>
1877 This wraps the specified method with the supplied subroutine
1878 reference. The modifier will be called as a method itself, and will
1879 receive the same arguments as are passed to the method.
1881 When the wrapped methods exits, the modifier will be called.
1883 The return value of the modifier will be ignored.
1885 =item B<< $metaclass->add_around_method_modifier($method_name, $code) >>
1887 This wraps the specified method with the supplied subroutine
1890 The first argument passed to the modifier will be a subroutine
1891 reference to the wrapped method. The second argument is the object,
1892 and after that come any arguments passed when the method is called.
1894 The around modifier can choose to call the original method, as well as
1895 what arguments to pass if it does so.
1897 The return value of the modifier is what will be seen by the caller.
1901 =head2 Introspection
1905 =item B<< Class::MOP::Class->meta >>
1907 This will return a L<Class::MOP::Class> instance for this class.
1909 It should also be noted that L<Class::MOP> will actually bootstrap
1910 this module by installing a number of attribute meta-objects into its
1917 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1919 =head1 COPYRIGHT AND LICENSE
1921 Copyright 2006-2009 by Infinity Interactive, Inc.
1923 L<http://www.iinteractive.com>
1925 This library is free software; you can redistribute it and/or modify
1926 it under the same terms as Perl itself.