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 my $options = @_ == 1 ? $_[0] : {@_};
113 # inherited from Class::MOP::Package
114 'package' => $options->{package},
117 # since the following attributes will
118 # actually be loaded from the symbol
119 # table, and actually bypass the instance
120 # entirely, we can just leave these things
121 # listed here for reference, because they
122 # should not actually have a value associated
124 'namespace' => \undef,
126 # inherited from Class::MOP::Module
128 'authority' => \undef,
130 # defined in Class::MOP::Class
131 'superclasses' => \undef,
135 'attribute_metaclass' =>
136 ( $options->{'attribute_metaclass'} || 'Class::MOP::Attribute' ),
137 'method_metaclass' =>
138 ( $options->{'method_metaclass'} || 'Class::MOP::Method' ),
139 'wrapped_method_metaclass' => (
140 $options->{'wrapped_method_metaclass'}
141 || 'Class::MOP::Method::Wrapped'
143 'instance_metaclass' =>
144 ( $options->{'instance_metaclass'} || 'Class::MOP::Instance' ),
145 'immutable_trait' => (
146 $options->{'immutable_trait'}
147 || 'Class::MOP::Class::Immutable::Trait'
149 'constructor_name' => ( $options->{constructor_name} || 'new' ),
150 'constructor_class' => (
151 $options->{constructor_class} || 'Class::MOP::Method::Constructor'
153 'destructor_class' => $options->{destructor_class},
157 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
158 sub update_package_cache_flag {
161 # we can manually update the cache number
162 # since we are actually adding the method
163 # to our cache as well. This avoids us
164 # having to regenerate the method_map.
166 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
170 sub check_metaclass_compatibility {
171 Carp::cluck('The check_metaclass_compatibility method has been made private.'
172 . " The public version is deprecated and will be removed in a future release.\n");
173 shift->_check_metaclass_compatibility(@_);
176 sub _check_metaclass_compatibility {
179 # this is always okay ...
180 return if ref($self) eq 'Class::MOP::Class' &&
181 $self->instance_metaclass eq 'Class::MOP::Instance';
183 my @class_list = $self->linearized_isa;
184 shift @class_list; # shift off $self->name
186 foreach my $superclass_name (@class_list) {
187 my $super_meta = Class::MOP::get_metaclass_by_name($superclass_name) || next;
190 # we need to deal with the possibility
191 # of class immutability here, and then
192 # get the name of the class appropriately
194 = $super_meta->is_immutable
195 ? $super_meta->get_mutable_metaclass_name()
198 ($self->isa($super_meta_type))
199 || confess "The metaclass of " . $self->name . " ("
200 . (ref($self)) . ")" . " is not compatible with the " .
201 "metaclass of its superclass, ".$superclass_name . " ("
202 . ($super_meta_type) . ")";
204 # we also need to check that instance metaclasses
205 # are compatibile in the same the class.
206 ($self->instance_metaclass->isa($super_meta->instance_metaclass))
207 || confess "The instance metaclass for " . $self->name . " (" . ($self->instance_metaclass) . ")" .
208 " is not compatible with the " .
209 "instance metaclass of its superclass, " . $superclass_name . " (" . ($super_meta->instance_metaclass) . ")";
217 # this should be sufficient, if you have a
218 # use case where it is not, write a test and
220 my $ANON_CLASS_SERIAL = 0;
223 # we need a sufficiently annoying prefix
224 # this should suffice for now, this is
225 # used in a couple of places below, so
226 # need to put it up here for now.
227 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
231 no warnings 'uninitialized';
232 $self->name =~ /^$ANON_CLASS_PREFIX/;
235 sub create_anon_class {
236 my ($class, %options) = @_;
237 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
238 return $class->create($package_name, %options);
242 # this will only get called for
243 # anon-classes, all other calls
244 # are assumed to occur during
245 # global destruction and so don't
246 # really need to be handled explicitly
250 return if in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
252 no warnings 'uninitialized';
253 my $name = $self->name;
254 return unless $name =~ /^$ANON_CLASS_PREFIX/;
255 # Moose does a weird thing where it replaces the metaclass for
256 # class when fixing metaclass incompatibility. In that case,
257 # we don't want to clean out the namespace now. We can detect
258 # that because Moose will explicitly update the singleton
259 # cache in Class::MOP.
260 my $current_meta = Class::MOP::get_metaclass_by_name($name);
261 return if $current_meta ne $self;
263 my ($serial_id) = ($name =~ /^$ANON_CLASS_PREFIX(\d+)/);
265 @{$name . '::ISA'} = ();
266 %{$name . '::'} = ();
267 delete ${$ANON_CLASS_PREFIX}{$serial_id . '::'};
269 Class::MOP::remove_metaclass_by_name($name);
274 # creating classes with MOP ...
277 my ( $class, @args ) = @_;
279 unshift @args, 'package' if @args % 2 == 1;
281 my (%options) = @args;
282 my $package_name = $options{package};
284 (ref $options{superclasses} eq 'ARRAY')
285 || confess "You must pass an ARRAY ref of superclasses"
286 if exists $options{superclasses};
288 (ref $options{attributes} eq 'ARRAY')
289 || confess "You must pass an ARRAY ref of attributes"
290 if exists $options{attributes};
292 (ref $options{methods} eq 'HASH')
293 || confess "You must pass a HASH ref of methods"
294 if exists $options{methods};
296 my (%initialize_options) = @args;
297 delete @initialize_options{qw(
305 my $meta = $class->initialize( $package_name => %initialize_options );
307 $meta->_instantiate_module( $options{version}, $options{authority} );
310 $meta->add_method('meta' => sub {
311 $class->initialize(ref($_[0]) || $_[0]);
314 $meta->superclasses(@{$options{superclasses}})
315 if exists $options{superclasses};
317 # process attributes first, so that they can
318 # install accessors, but locally defined methods
319 # can then overwrite them. It is maybe a little odd, but
320 # I think this should be the order of things.
321 if (exists $options{attributes}) {
322 foreach my $attr (@{$options{attributes}}) {
323 $meta->add_attribute($attr);
326 if (exists $options{methods}) {
327 foreach my $method_name (keys %{$options{methods}}) {
328 $meta->add_method($method_name, $options{methods}->{$method_name});
337 # all these attribute readers will be bootstrapped
338 # away in the Class::MOP bootstrap section
340 sub get_attribute_map { $_[0]->{'attributes'} }
341 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
342 sub method_metaclass { $_[0]->{'method_metaclass'} }
343 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
344 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
345 sub immutable_trait { $_[0]->{'immutable_trait'} }
346 sub constructor_class { $_[0]->{'constructor_class'} }
347 sub constructor_name { $_[0]->{'constructor_name'} }
348 sub destructor_class { $_[0]->{'destructor_class'} }
350 sub _method_map { $_[0]->{'methods'} }
352 # Instance Construction & Cloning
358 # we need to protect the integrity of the
359 # Class::MOP::Class singletons here, so we
360 # delegate this to &construct_class_instance
361 # which will deal with the singletons
362 return $class->_construct_class_instance(@_)
363 if $class->name->isa('Class::MOP::Class');
364 return $class->_construct_instance(@_);
367 sub construct_instance {
368 Carp::cluck('The construct_instance method has been made private.'
369 . " The public version is deprecated and will be removed in a future release.\n");
370 shift->_construct_instance(@_);
373 sub _construct_instance {
375 my $params = @_ == 1 ? $_[0] : {@_};
376 my $meta_instance = $class->get_meta_instance();
378 # the code below is almost certainly incorrect
379 # but this is foreign inheritance, so we might
380 # have to kludge it in the end.
381 my $instance = $params->{__INSTANCE__} || $meta_instance->create_instance();
382 foreach my $attr ($class->get_all_attributes()) {
383 $attr->initialize_instance_slot($meta_instance, $instance, $params);
386 # this will only work for a HASH instance type
387 if ($class->is_anon_class) {
388 (Scalar::Util::reftype($instance) eq 'HASH')
389 || confess "Currently only HASH based instances are supported with instance of anon-classes";
391 # At some point we should make this official
392 # as a reserved slot name, but right now I am
393 # going to keep it here.
394 # my $RESERVED_MOP_SLOT = '__MOP__';
395 $instance->{'__MOP__'} = $class;
401 sub get_meta_instance {
403 $self->{'_meta_instance'} ||= $self->_create_meta_instance();
406 sub create_meta_instance {
407 Carp::cluck('The create_meta_instance method has been made private.'
408 . " The public version is deprecated and will be removed in a future release.\n");
409 shift->_create_meta_instance(@_);
412 sub _create_meta_instance {
415 my $instance = $self->instance_metaclass->new(
416 associated_metaclass => $self,
417 attributes => [ $self->get_all_attributes() ],
420 $self->add_meta_instance_dependencies()
421 if $instance->is_dependent_on_superclasses();
428 my $instance = shift;
429 (blessed($instance) && $instance->isa($class->name))
430 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
433 # we need to protect the integrity of the
434 # Class::MOP::Class singletons here, they
435 # should not be cloned.
436 return $instance if $instance->isa('Class::MOP::Class');
437 $class->_clone_instance($instance, @_);
441 Carp::cluck('The clone_instance method has been made private.'
442 . " The public version is deprecated and will be removed in a future release.\n");
443 shift->_clone_instance(@_);
446 sub _clone_instance {
447 my ($class, $instance, %params) = @_;
449 || confess "You can only clone instances, ($instance) is not a blessed instance";
450 my $meta_instance = $class->get_meta_instance();
451 my $clone = $meta_instance->clone_instance($instance);
452 foreach my $attr ($class->get_all_attributes()) {
453 if ( defined( my $init_arg = $attr->init_arg ) ) {
454 if (exists $params{$init_arg}) {
455 $attr->set_value($clone, $params{$init_arg});
462 sub rebless_instance {
463 my ($self, $instance, %params) = @_;
465 my $old_metaclass = Class::MOP::class_of($instance);
467 my $old_class = $old_metaclass ? $old_metaclass->name : blessed($instance);
468 $self->name->isa($old_class)
469 || confess "You may rebless only into a subclass of ($old_class), of which (". $self->name .") isn't.";
471 $old_metaclass->rebless_instance_away($instance, $self, %params)
474 my $meta_instance = $self->get_meta_instance();
477 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
478 $meta_instance->rebless_instance_structure($_[1], $self);
480 foreach my $attr ( $self->get_all_attributes ) {
481 if ( $attr->has_value($instance) ) {
482 if ( defined( my $init_arg = $attr->init_arg ) ) {
483 $params{$init_arg} = $attr->get_value($instance)
484 unless exists $params{$init_arg};
487 $attr->set_value($instance, $attr->get_value($instance));
492 foreach my $attr ($self->get_all_attributes) {
493 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
499 sub rebless_instance_away {
500 # this intentionally does nothing, it is just a hook
507 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
510 @{$self->get_package_symbol($var_spec)} = @supers;
513 # on 5.8 and below, we need to call
514 # a method to get Perl to detect
515 # a cycle in the class hierarchy
516 my $class = $self->name;
520 # we need to check the metaclass
521 # compatibility here so that we can
522 # be sure that the superclass is
523 # not potentially creating an issues
524 # we don't know about
526 $self->_check_metaclass_compatibility();
527 $self->_superclasses_updated();
529 @{$self->get_package_symbol($var_spec)};
532 sub _superclasses_updated {
534 $self->update_meta_instance_dependencies();
539 my $super_class = $self->name;
541 return @{ $super_class->mro::get_isarev() };
544 sub direct_subclasses {
546 my $super_class = $self->name;
551 } Class::MOP::Class->initialize($_)->superclasses
556 return @{ mro::get_linear_isa( (shift)->name ) };
559 sub class_precedence_list {
561 my $name = $self->name;
563 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
565 # We need to check for circular inheritance here
566 # if we are are not on 5.10, cause 5.8 detects it
567 # late. This will do nothing if all is well, and
568 # blow up otherwise. Yes, it's an ugly hack, better
569 # suggestions are welcome.
571 ($name || return)->isa('This is a test for circular inheritance')
574 # if our mro is c3, we can
575 # just grab the linear_isa
576 if (mro::get_mro($name) eq 'c3') {
577 return @{ mro::get_linear_isa($name) }
581 # we can't grab the linear_isa for dfs
582 # since it has all the duplicates
587 $self->initialize($_)->class_precedence_list()
588 } $self->superclasses()
595 sub wrap_method_body {
596 my ( $self, %args ) = @_;
598 ('CODE' eq ref $args{body})
599 || confess "Your code block must be a CODE reference";
601 $self->method_metaclass->wrap(
602 package_name => $self->name,
608 my ($self, $method_name, $method) = @_;
609 (defined $method_name && $method_name)
610 || confess "You must define a method name";
613 if (blessed($method)) {
614 $body = $method->body;
615 if ($method->package_name ne $self->name) {
616 $method = $method->clone(
617 package_name => $self->name,
619 ) if $method->can('clone');
622 $method->attach_to_class($self);
623 $self->_method_map->{$method_name} = $method;
626 # If a raw code reference is supplied, its method object is not created.
627 # The method object won't be created until required.
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, $code) = @_;
724 my($code_package, $code_name) = Class::MOP::get_code_info($code);
726 && $code_package eq $self->name
727 || ($code_package eq 'constant' && $code_name eq '__ANON__');
731 my ($self, $method_name) = @_;
732 (defined $method_name && $method_name)
733 || confess "You must define a method name";
735 return defined($self->get_method($method_name));
739 my ($self, $method_name) = @_;
740 (defined $method_name && $method_name)
741 || confess "You must define a method name";
743 my $method_map = $self->_method_map;
744 my $method_object = $method_map->{$method_name};
745 my $code = $self->get_package_symbol({
746 name => $method_name,
751 if (!($method_object && $method_object->body == ($code || 0))){
752 if ($code && $self->_code_is_mine($code)) {
753 $method_object = $method_map->{$method_name} = $self->wrap_method_body(
755 name => $method_name,
756 associated_metaclass => $self,
760 delete $method_map->{$method_name};
765 return $method_object;
769 my ($self, $method_name) = @_;
770 (defined $method_name && $method_name)
771 || confess "You must define a method name";
773 my $removed_method = delete $self->get_method_map->{$method_name};
775 $self->remove_package_symbol(
776 { sigil => '&', type => 'CODE', name => $method_name }
779 $removed_method->detach_from_class if $removed_method;
781 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
783 return $removed_method;
786 sub get_method_list {
788 keys %{$self->get_method_map};
791 sub find_method_by_name {
792 my ($self, $method_name) = @_;
793 (defined $method_name && $method_name)
794 || confess "You must define a method name to find";
795 foreach my $class ($self->linearized_isa) {
796 # fetch the meta-class ...
797 my $meta = $self->initialize($class);
798 return $meta->get_method($method_name)
799 if $meta->has_method($method_name);
804 sub get_all_methods {
806 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
807 return values %methods;
810 sub compute_all_applicable_methods {
811 Carp::cluck('The compute_all_applicable_methods method is deprecated.'
812 . " Use get_all_methods instead.\n");
817 class => $_->package_name,
818 code => $_, # sigh, overloading
820 } shift->get_all_methods(@_);
823 sub get_all_method_names {
826 grep { $uniq{$_}++ == 0 } map { $_->name } $self->get_all_methods;
829 sub find_all_methods_by_name {
830 my ($self, $method_name) = @_;
831 (defined $method_name && $method_name)
832 || confess "You must define a method name to find";
834 foreach my $class ($self->linearized_isa) {
835 # fetch the meta-class ...
836 my $meta = $self->initialize($class);
838 name => $method_name,
840 code => $meta->get_method($method_name)
841 } if $meta->has_method($method_name);
846 sub find_next_method_by_name {
847 my ($self, $method_name) = @_;
848 (defined $method_name && $method_name)
849 || confess "You must define a method name to find";
850 my @cpl = $self->linearized_isa;
851 shift @cpl; # discard ourselves
852 foreach my $class (@cpl) {
853 # fetch the meta-class ...
854 my $meta = $self->initialize($class);
855 return $meta->get_method($method_name)
856 if $meta->has_method($method_name);
865 # either we have an attribute object already
866 # or we need to create one from the args provided
867 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
868 # make sure it is derived from the correct type though
869 ($attribute->isa('Class::MOP::Attribute'))
870 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
872 # first we attach our new attribute
873 # because it might need certain information
874 # about the class which it is attached to
875 $attribute->attach_to_class($self);
877 # then we remove attributes of a conflicting
878 # name here so that we can properly detach
879 # the old attr object, and remove any
880 # accessors it would have generated
881 if ( $self->has_attribute($attribute->name) ) {
882 $self->remove_attribute($attribute->name);
884 $self->invalidate_meta_instances();
887 # get our count of previously inserted attributes and
888 # increment by one so this attribute knows its order
889 my $order = (scalar keys %{$self->get_attribute_map}) - 1;
890 $attribute->_set_insertion_order($order + 1);
892 # then onto installing the new accessors
893 $self->get_attribute_map->{$attribute->name} = $attribute;
895 # invalidate package flag here
899 eval { $attribute->install_accessors() };
903 $self->remove_attribute($attribute->name);
910 sub update_meta_instance_dependencies {
913 if ( $self->{meta_instance_dependencies} ) {
914 return $self->add_meta_instance_dependencies;
918 sub add_meta_instance_dependencies {
921 $self->remove_meta_instance_dependencies;
923 my @attrs = $self->get_all_attributes();
926 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
928 foreach my $class ( @classes ) {
929 $class->add_dependent_meta_instance($self);
932 $self->{meta_instance_dependencies} = \@classes;
935 sub remove_meta_instance_dependencies {
938 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
939 foreach my $class ( @$classes ) {
940 $class->remove_dependent_meta_instance($self);
950 sub add_dependent_meta_instance {
951 my ( $self, $metaclass ) = @_;
952 push @{ $self->{dependent_meta_instances} }, $metaclass;
955 sub remove_dependent_meta_instance {
956 my ( $self, $metaclass ) = @_;
957 my $name = $metaclass->name;
958 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
961 sub invalidate_meta_instances {
963 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
966 sub invalidate_meta_instance {
968 undef $self->{_meta_instance};
972 my ($self, $attribute_name) = @_;
973 (defined $attribute_name && $attribute_name)
974 || confess "You must define an attribute name";
975 exists $self->get_attribute_map->{$attribute_name};
979 my ($self, $attribute_name) = @_;
980 (defined $attribute_name && $attribute_name)
981 || confess "You must define an attribute name";
982 return $self->get_attribute_map->{$attribute_name}
984 # this will return undef anyway, so no need ...
985 # if $self->has_attribute($attribute_name);
989 sub remove_attribute {
990 my ($self, $attribute_name) = @_;
991 (defined $attribute_name && $attribute_name)
992 || confess "You must define an attribute name";
993 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
994 return unless defined $removed_attribute;
995 delete $self->get_attribute_map->{$attribute_name};
996 $self->invalidate_meta_instances();
997 $removed_attribute->remove_accessors();
998 $removed_attribute->detach_from_class();
999 return $removed_attribute;
1002 sub get_attribute_list {
1004 keys %{$self->get_attribute_map};
1007 sub get_all_attributes {
1009 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
1010 return values %attrs;
1013 sub compute_all_applicable_attributes {
1014 Carp::cluck('The compute_all_applicable_attributes method has been deprecated.'
1015 . " Use get_all_attributes instead.\n");
1017 shift->get_all_attributes(@_);
1020 sub find_attribute_by_name {
1021 my ($self, $attr_name) = @_;
1022 foreach my $class ($self->linearized_isa) {
1023 # fetch the meta-class ...
1024 my $meta = $self->initialize($class);
1025 return $meta->get_attribute($attr_name)
1026 if $meta->has_attribute($attr_name);
1031 # check if we can reinitialize
1035 # if any local attr is defined
1036 return if $self->get_attribute_list;
1038 # or any non-declared methods
1039 if ( my @methods = values %{ $self->get_method_map } ) {
1040 my $metaclass = $self->method_metaclass;
1041 foreach my $method ( @methods ) {
1042 return if $method->isa("Class::MOP::Method::Generated");
1043 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1052 sub is_mutable { 1 }
1053 sub is_immutable { 0 }
1055 sub _immutable_options {
1056 my ( $self, @args ) = @_;
1059 inline_accessors => 1,
1060 inline_constructor => 1,
1061 inline_destructor => 0,
1063 immutable_trait => $self->immutable_trait,
1064 constructor_name => $self->constructor_name,
1065 constructor_class => $self->constructor_class,
1066 destructor_class => $self->destructor_class,
1071 sub make_immutable {
1072 my ( $self, @args ) = @_;
1074 if ( $self->is_mutable ) {
1075 $self->_initialize_immutable( $self->_immutable_options(@args) );
1076 $self->_rebless_as_immutable(@args);
1087 if ( $self->is_immutable ) {
1088 my @args = $self->immutable_options;
1089 $self->_rebless_as_mutable();
1090 $self->_remove_inlined_code(@args);
1091 delete $self->{__immutable};
1099 sub _rebless_as_immutable {
1100 my ( $self, @args ) = @_;
1102 $self->{__immutable}{original_class} = ref $self;
1104 bless $self => $self->_immutable_metaclass(@args);
1107 sub _immutable_metaclass {
1108 my ( $self, %args ) = @_;
1110 if ( my $class = $args{immutable_metaclass} ) {
1114 my $trait = $args{immutable_trait} = $self->immutable_trait
1115 || confess "no immutable trait specified for $self";
1117 my $meta_attr = $self->meta->find_attribute_by_name("immutable_trait");
1121 if ( $meta_attr and $trait eq $meta_attr->default ) {
1122 # if the trait is the same as the default we try and pick a
1123 # predictable name for the immutable metaclass
1124 $class_name = 'Class::MOP::Class::Immutable::' . ref($self);
1127 $class_name = join '::', 'Class::MOP::Class::Immutable::CustomTrait',
1128 $trait, 'ForMetaClass', ref($self);
1132 if Class::MOP::is_class_loaded($class_name);
1134 # If the metaclass is a subclass of CMOP::Class which has had
1135 # metaclass roles applied (via Moose), then we want to make sure
1136 # that we preserve that anonymous class (see Fey::ORM for an
1137 # example of where this matters).
1139 = $self->meta->is_immutable
1140 ? $self->meta->get_mutable_metaclass_name
1143 my $meta = $meta_name->create(
1145 superclasses => [ ref $self ],
1148 Class::MOP::load_class($trait);
1149 for my $meth ( Class::MOP::Class->initialize($trait)->get_all_methods ) {
1150 next if $meta->has_method( $meth->name );
1152 if ( $meta->find_method_by_name( $meth->name ) ) {
1153 $meta->add_around_method_modifier( $meth->name, $meth->body );
1156 $meta->add_method( $meth->name, $meth->clone );
1160 $meta->make_immutable( inline_constructor => 0 );
1165 sub _remove_inlined_code {
1168 $self->remove_method( $_->name ) for $self->_inlined_methods;
1170 delete $self->{__immutable}{inlined_methods};
1173 sub _inlined_methods { @{ $_[0]{__immutable}{inlined_methods} || [] } }
1175 sub _add_inlined_method {
1176 my ( $self, $method ) = @_;
1178 push @{ $self->{__immutable}{inlined_methods} ||= [] }, $method;
1181 sub _initialize_immutable {
1182 my ( $self, %args ) = @_;
1184 $self->{__immutable}{options} = \%args;
1185 $self->_install_inlined_code(%args);
1188 sub _install_inlined_code {
1189 my ( $self, %args ) = @_;
1192 $self->_inline_accessors(%args) if $args{inline_accessors};
1193 $self->_inline_constructor(%args) if $args{inline_constructor};
1194 $self->_inline_destructor(%args) if $args{inline_destructor};
1197 sub _rebless_as_mutable {
1200 bless $self, $self->get_mutable_metaclass_name;
1205 sub _inline_accessors {
1208 foreach my $attr_name ( $self->get_attribute_list ) {
1209 $self->get_attribute($attr_name)->install_accessors(1);
1213 sub _inline_constructor {
1214 my ( $self, %args ) = @_;
1216 my $name = $args{constructor_name};
1218 if ( $self->has_method($name) && !$args{replace_constructor} ) {
1219 my $class = $self->name;
1220 warn "Not inlining a constructor for $class since it defines"
1221 . " its own constructor.\n"
1222 . "If you are certain you don't need to inline your"
1223 . " constructor, specify inline_constructor => 0 in your"
1224 . " call to $class->meta->make_immutable\n";
1228 my $constructor_class = $args{constructor_class};
1230 Class::MOP::load_class($constructor_class);
1232 my $constructor = $constructor_class->new(
1236 package_name => $self->name,
1240 if ( $args{replace_constructor} or $constructor->can_be_inlined ) {
1241 $self->add_method( $name => $constructor );
1242 $self->_add_inlined_method($constructor);
1246 sub _inline_destructor {
1247 my ( $self, %args ) = @_;
1249 ( exists $args{destructor_class} && defined $args{destructor_class} )
1250 || confess "The 'inline_destructor' option is present, but "
1251 . "no destructor class was specified";
1253 if ( $self->has_method('DESTROY') && ! $args{replace_destructor} ) {
1254 my $class = $self->name;
1255 warn "Not inlining a destructor for $class since it defines"
1256 . " its own destructor.\n";
1260 my $destructor_class = $args{destructor_class};
1262 Class::MOP::load_class($destructor_class);
1264 return unless $destructor_class->is_needed($self);
1266 my $destructor = $destructor_class->new(
1269 package_name => $self->name,
1273 if ( $args{replace_destructor} or $destructor->can_be_inlined ) {
1274 $self->add_method( 'DESTROY' => $destructor );
1275 $self->_add_inlined_method($destructor);
1287 Class::MOP::Class - Class Meta Object
1291 # assuming that class Foo
1292 # has been defined, you can
1294 # use this for introspection ...
1296 # add a method to Foo ...
1297 Foo->meta->add_method( 'bar' => sub {...} )
1299 # get a list of all the classes searched
1300 # the method dispatcher in the correct order
1301 Foo->meta->class_precedence_list()
1303 # remove a method from Foo
1304 Foo->meta->remove_method('bar');
1306 # or use this to actually create classes ...
1308 Class::MOP::Class->create(
1311 superclasses => ['Foo'],
1313 Class::MOP::Attribute->new('$bar'),
1314 Class::MOP::Attribute->new('$baz'),
1317 calculate_bar => sub {...},
1318 construct_baz => sub {...}
1325 The Class Protocol is the largest and most complex part of the
1326 Class::MOP meta-object protocol. It controls the introspection and
1327 manipulation of Perl 5 classes, and it can create them as well. The
1328 best way to understand what this module can do, is to read the
1329 documentation for each of its methods.
1333 C<Class::MOP::Class> is a subclass of L<Class::MOP::Module>.
1337 =head2 Class construction
1339 These methods all create new C<Class::MOP::Class> objects. These
1340 objects can represent existing classes, or they can be used to create
1341 new classes from scratch.
1343 The metaclass object for a given class is a singleton. If you attempt
1344 to create a metaclass for the same class twice, you will just get the
1349 =item B<< Class::MOP::Class->create($package_name, %options) >>
1351 This method creates a new C<Class::MOP::Class> object with the given
1352 package name. It accepts a number of options.
1358 An optional version number for the newly created package.
1362 An optional authority for the newly created package.
1364 =item * superclasses
1366 An optional array reference of superclass names.
1370 An optional hash reference of methods for the class. The keys of the
1371 hash reference are method names, and values are subroutine references.
1375 An optional array reference of attributes.
1377 An attribute can be passed as an existing L<Class::MOP::Attribute>
1378 object, I<or> or as a hash reference of options which will be passed
1379 to the attribute metaclass's constructor.
1383 =item B<< Class::MOP::Class->create_anon_class(%options) >>
1385 This method works just like C<< Class::MOP::Class->create >> but it
1386 creates an "anonymous" class. In fact, the class does have a name, but
1387 that name is a unique name generated internally by this module.
1389 It accepts the same C<superclasses>, C<methods>, and C<attributes>
1390 parameters that C<create> accepts.
1392 Anonymous classes are destroyed once the metaclass they are attached
1393 to goes out of scope, and will be removed from Perl's internal symbol
1396 All instances of an anonymous class keep a special reference to the
1397 metaclass object, which prevents the metaclass from going out of scope
1398 while any instances exist.
1400 This only works if the instance if based on a hash reference, however.
1402 =item B<< Class::MOP::Class->initialize($package_name, %options) >>
1404 This method will initialize a C<Class::MOP::Class> object for the
1405 named package. Unlike C<create>, this method I<will not> create a new
1408 The purpose of this method is to retrieve a C<Class::MOP::Class>
1409 object for introspecting an existing class.
1411 If an existing C<Class::MOP::Class> object exists for the named
1412 package, it will be returned, and any options provided will be
1415 If the object does not yet exist, it will be created.
1417 The valid options that can be passed to this method are
1418 C<attribute_metaclass>, C<method_metaclass>,
1419 C<wrapped_method_metaclass>, and C<instance_metaclass>. These are all
1420 optional, and default to the appropriate class in the C<Class::MOP>
1425 =head2 Object instance construction and cloning
1427 These methods are all related to creating and/or cloning object
1432 =item B<< $metaclass->clone_object($instance, %params) >>
1434 This method clones an existing object instance. Any parameters you
1435 provide are will override existing attribute values in the object.
1437 This is a convenience method for cloning an object instance, then
1438 blessing it into the appropriate package.
1440 You could implement a clone method in your class, using this method:
1443 my ($self, %params) = @_;
1444 $self->meta->clone_object($self, %params);
1447 =item B<< $metaclass->rebless_instance($instance, %params) >>
1449 This method changes the class of C<$instance> to the metaclass's class.
1451 You can only rebless an instance into a subclass of its current
1452 class. If you pass any additional parameters, these will be treated
1453 like constructor parameters and used to initialize the object's
1454 attributes. Any existing attributes that are already set will be
1457 Before reblessing the instance, this method will call
1458 C<rebless_instance_away> on the instance's current metaclass. This method
1459 will be passed the instance, the new metaclass, and any parameters
1460 specified to C<rebless_instance>. By default, C<rebless_instance_away>
1461 does nothing; it is merely a hook.
1463 =item B<< $metaclass->new_object(%params) >>
1465 This method is used to create a new object of the metaclass's
1466 class. Any parameters you provide are used to initialize the
1467 instance's attributes. A special C<__INSTANCE__> key can be passed to
1468 provide an already generated instance, rather than having Class::MOP
1469 generate it for you. This is mostly useful for using Class::MOP with
1470 foreign classes, which generally generate instances using their own
1473 =item B<< $metaclass->instance_metaclass >>
1475 Returns the class name of the instance metaclass, see
1476 L<Class::MOP::Instance> for more information on the instance
1479 =item B<< $metaclass->get_meta_instance >>
1481 Returns an instance of the C<instance_metaclass> to be used in the
1482 construction of a new instance of the class.
1486 =head2 Informational predicates
1488 These are a few predicate methods for asking information about the
1493 =item B<< $metaclass->is_anon_class >>
1495 This returns true if the class was created by calling C<<
1496 Class::MOP::Class->create_anon_class >>.
1498 =item B<< $metaclass->is_mutable >>
1500 This returns true if the class is still mutable.
1502 =item B<< $metaclass->is_immutable >>
1504 This returns true if the class has been made immutable.
1506 =item B<< $metaclass->is_pristine >>
1508 A class is I<not> pristine if it has non-inherited attributes or if it
1509 has any generated methods.
1513 =head2 Inheritance Relationships
1517 =item B<< $metaclass->superclasses(@superclasses) >>
1519 This is a read-write accessor which represents the superclass
1520 relationships of the metaclass's class.
1522 This is basically sugar around getting and setting C<@ISA>.
1524 =item B<< $metaclass->class_precedence_list >>
1526 This returns a list of all of the class's ancestor classes. The
1527 classes are returned in method dispatch order.
1529 =item B<< $metaclass->linearized_isa >>
1531 This returns a list based on C<class_precedence_list> but with all
1534 =item B<< $metaclass->subclasses >>
1536 This returns a list of all subclasses for this class, even indirect
1539 =item B<< $metaclass->direct_subclasses >>
1541 This returns a list of immediate subclasses for this class, which does not
1542 include indirect subclasses.
1546 =head2 Method introspection and creation
1548 These methods allow you to introspect a class's methods, as well as
1549 add, remove, or change methods.
1551 Determining what is truly a method in a Perl 5 class requires some
1552 heuristics (aka guessing).
1554 Methods defined outside the package with a fully qualified name (C<sub
1555 Package::name { ... }>) will be included. Similarly, methods named
1556 with a fully qualified name using L<Sub::Name> are also included.
1558 However, we attempt to ignore imported functions.
1560 Ultimately, we are using heuristics to determine what truly is a
1561 method in a class, and these heuristics may get the wrong answer in
1562 some edge cases. However, for most "normal" cases the heuristics work
1567 =item B<< $metaclass->get_method($method_name) >>
1569 This will return a L<Class::MOP::Method> for the specified
1570 C<$method_name>. If the class does not have the specified method, it
1573 =item B<< $metaclass->has_method($method_name) >>
1575 Returns a boolean indicating whether or not the class defines the
1576 named method. It does not include methods inherited from parent
1579 =item B<< $metaclass->get_method_map >>
1581 Returns a hash reference representing the methods defined in this
1582 class. The keys are method names and the values are
1583 L<Class::MOP::Method> objects.
1585 =item B<< $metaclass->get_method_list >>
1587 This will return a list of method I<names> for all methods defined in
1590 =item B<< $metaclass->get_all_methods >>
1592 This will traverse the inheritance hierarchy and return a list of all
1593 the L<Class::MOP::Method> objects for this class and its parents.
1595 =item B<< $metaclass->find_method_by_name($method_name) >>
1597 This will return a L<Class::MOP::Method> for the specified
1598 C<$method_name>. If the class does not have the specified method, it
1601 Unlike C<get_method>, this method I<will> look for the named method in
1604 =item B<< $metaclass->get_all_method_names >>
1606 This will return a list of method I<names> for all of this class's
1607 methods, including inherited methods.
1609 =item B<< $metaclass->find_all_methods_by_name($method_name) >>
1611 This method looks for the named method in the class and all of its
1612 parents. It returns every matching method it finds in the inheritance
1613 tree, so it returns a list of methods.
1615 Each method is returned as a hash reference with three keys. The keys
1616 are C<name>, C<class>, and C<code>. The C<code> key has a
1617 L<Class::MOP::Method> object as its value.
1619 The list of methods is distinct.
1621 =item B<< $metaclass->find_next_method_by_name($method_name) >>
1623 This method returns the first method in any superclass matching the
1624 given name. It is effectively the method that C<SUPER::$method_name>
1627 =item B<< $metaclass->add_method($method_name, $method) >>
1629 This method takes a method name and a subroutine reference, and adds
1630 the method to the class.
1632 The subroutine reference can be a L<Class::MOP::Method>, and you are
1633 strongly encouraged to pass a meta method object instead of a code
1634 reference. If you do so, that object gets stored as part of the
1635 class's method map directly. If not, the meta information will have to
1636 be recreated later, and may be incorrect.
1638 If you provide a method object, this method will clone that object if
1639 the object's package name does not match the class name. This lets us
1640 track the original source of any methods added from other classes
1641 (notably Moose roles).
1643 =item B<< $metaclass->remove_method($method_name) >>
1645 Remove the named method from the class. This method returns the
1646 L<Class::MOP::Method> object for the method.
1648 =item B<< $metaclass->method_metaclass >>
1650 Returns the class name of the method metaclass, see
1651 L<Class::MOP::Method> for more information on the method metaclass.
1653 =item B<< $metaclass->wrapped_method_metaclass >>
1655 Returns the class name of the wrapped method metaclass, see
1656 L<Class::MOP::Method::Wrapped> for more information on the wrapped
1661 =head2 Attribute introspection and creation
1663 Because Perl 5 does not have a core concept of attributes in classes,
1664 we can only return information about attributes which have been added
1665 via this class's methods. We cannot discover information about
1666 attributes which are defined in terms of "regular" Perl 5 methods.
1670 =item B<< $metaclass->get_attribute($attribute_name) >>
1672 This will return a L<Class::MOP::Attribute> for the specified
1673 C<$attribute_name>. If the class does not have the specified
1674 attribute, it returns C<undef>.
1676 NOTE that get_attribute does not search superclasses, for that you
1677 need to use C<find_attribute_by_name>.
1679 =item B<< $metaclass->has_attribute($attribute_name) >>
1681 Returns a boolean indicating whether or not the class defines the
1682 named attribute. It does not include attributes inherited from parent
1685 =item B<< $metaclass->get_attribute_map >>
1687 Returns a hash reference representing the attributes defined in this
1688 class. The keys are attribute names and the values are
1689 L<Class::MOP::Attribute> objects.
1691 =item B<< $metaclass->get_attribute_list >>
1693 This will return a list of attributes I<names> for all attributes
1694 defined in this class.
1696 =item B<< $metaclass->get_all_attributes >>
1698 This will traverse the inheritance hierarchy and return a list of all
1699 the L<Class::MOP::Attribute> objects for this class and its parents.
1701 =item B<< $metaclass->find_attribute_by_name($attribute_name) >>
1703 This will return a L<Class::MOP::Attribute> for the specified
1704 C<$attribute_name>. If the class does not have the specified
1705 attribute, it returns C<undef>
1707 Unlike C<get_attribute>, this attribute I<will> look for the named
1708 attribute in superclasses.
1710 =item B<< $metaclass->add_attribute(...) >>
1712 This method accepts either an existing L<Class::MOP::Attribute>
1713 object, or parameters suitable for passing to that class's C<new>
1716 The attribute provided will be added to the class.
1718 Any accessor methods defined by the attribute will be added to the
1719 class when the attribute is added.
1721 If an attribute of the same name already exists, the old attribute
1722 will be removed first.
1724 =item B<< $metaclass->remove_attribute($attribute_name) >>
1726 This will remove the named attribute from the class, and
1727 L<Class::MOP::Attribute> object.
1729 Removing an attribute also removes any accessor methods defined by the
1732 However, note that removing an attribute will only affect I<future>
1733 object instances created for this class, not existing instances.
1735 =item B<< $metaclass->attribute_metaclass >>
1737 Returns the class name of the attribute metaclass for this class. By
1738 default, this is L<Class::MOP::Attribute>. for more information on
1742 =head2 Class Immutability
1744 Making a class immutable "freezes" the class definition. You can no
1745 longer call methods which alter the class, such as adding or removing
1746 methods or attributes.
1748 Making a class immutable lets us optimize the class by inlining some
1749 methods, and also allows us to optimize some methods on the metaclass
1752 After immutabilization, the metaclass object will cache most
1753 informational methods such as C<get_method_map> and
1754 C<get_all_attributes>. Methods which would alter the class, such as
1755 C<add_attribute>, C<add_method>, and so on will throw an error on an
1756 immutable metaclass object.
1758 The immutabilization system in L<Moose> takes much greater advantage
1759 of the inlining features than Class::MOP itself does.
1763 =item B<< $metaclass->make_immutable(%options) >>
1765 This method will create an immutable transformer and uses it to make
1766 the class and its metaclass object immutable.
1768 This method accepts the following options:
1772 =item * inline_accessors
1774 =item * inline_constructor
1776 =item * inline_destructor
1778 These are all booleans indicating whether the specified method(s)
1781 By default, accessors and the constructor are inlined, but not the
1784 =item * immutable_trait
1786 The name of a class which will be used as a parent class for the
1787 metaclass object being made immutable. This "trait" implements the
1788 post-immutability functionality of the metaclass (but not the
1789 transformation itself).
1791 This defaults to L<Class::MOP::Class::Immutable::Trait>.
1793 =item * constructor_name
1795 This is the constructor method name. This defaults to "new".
1797 =item * constructor_class
1799 The name of the method metaclass for constructors. It will be used to
1800 generate the inlined constructor. This defaults to
1801 "Class::MOP::Method::Constructor".
1803 =item * replace_constructor
1805 This is a boolean indicating whether an existing constructor should be
1806 replaced when inlining a constructor. This defaults to false.
1808 =item * destructor_class
1810 The name of the method metaclass for destructors. It will be used to
1811 generate the inlined destructor. This defaults to
1812 "Class::MOP::Method::Denstructor".
1814 =item * replace_destructor
1816 This is a boolean indicating whether an existing destructor should be
1817 replaced when inlining a destructor. This defaults to false.
1821 =item B<< $metaclass->make_mutable >>
1823 Calling this method reverse the immutabilization transformation.
1827 =head2 Method Modifiers
1829 Method modifiers are hooks which allow a method to be wrapped with
1830 I<before>, I<after> and I<around> method modifiers. Every time a
1831 method is called, it's modifiers are also called.
1833 A class can modify its own methods, as well as methods defined in
1836 =head3 How method modifiers work?
1838 Method modifiers work by wrapping the original method and then
1839 replacing it in the class's symbol table. The wrappers will handle
1840 calling all the modifiers in the appropriate order and preserving the
1841 calling context for the original method.
1843 The return values of C<before> and C<after> modifiers are
1844 ignored. This is because their purpose is B<not> to filter the input
1845 and output of the primary method (this is done with an I<around>
1848 This may seem like an odd restriction to some, but doing this allows
1849 for simple code to be added at the beginning or end of a method call
1850 without altering the function of the wrapped method or placing any
1851 extra responsibility on the code of the modifier.
1853 Of course if you have more complex needs, you can use the C<around>
1854 modifier which allows you to change both the parameters passed to the
1855 wrapped method, as well as its return value.
1857 Before and around modifiers are called in last-defined-first-called
1858 order, while after modifiers are called in first-defined-first-called
1859 order. So the call tree might looks something like this:
1871 =head3 What is the performance impact?
1873 Of course there is a performance cost associated with method
1874 modifiers, but we have made every effort to make that cost directly
1875 proportional to the number of modifier features you utilize.
1877 The wrapping method does it's best to B<only> do as much work as it
1878 absolutely needs to. In order to do this we have moved some of the
1879 performance costs to set-up time, where they are easier to amortize.
1881 All this said, our benchmarks have indicated the following:
1883 simple wrapper with no modifiers 100% slower
1884 simple wrapper with simple before modifier 400% slower
1885 simple wrapper with simple after modifier 450% slower
1886 simple wrapper with simple around modifier 500-550% slower
1887 simple wrapper with all 3 modifiers 1100% slower
1889 These numbers may seem daunting, but you must remember, every feature
1890 comes with some cost. To put things in perspective, just doing a
1891 simple C<AUTOLOAD> which does nothing but extract the name of the
1892 method called and return it costs about 400% over a normal method
1897 =item B<< $metaclass->add_before_method_modifier($method_name, $code) >>
1899 This wraps the specified method with the supplied subroutine
1900 reference. The modifier will be called as a method itself, and will
1901 receive the same arguments as are passed to the method.
1903 When the modifier exits, the wrapped method will be called.
1905 The return value of the modifier will be ignored.
1907 =item B<< $metaclass->add_after_method_modifier($method_name, $code) >>
1909 This wraps the specified method with the supplied subroutine
1910 reference. The modifier will be called as a method itself, and will
1911 receive the same arguments as are passed to the method.
1913 When the wrapped methods exits, the modifier will be called.
1915 The return value of the modifier will be ignored.
1917 =item B<< $metaclass->add_around_method_modifier($method_name, $code) >>
1919 This wraps the specified method with the supplied subroutine
1922 The first argument passed to the modifier will be a subroutine
1923 reference to the wrapped method. The second argument is the object,
1924 and after that come any arguments passed when the method is called.
1926 The around modifier can choose to call the original method, as well as
1927 what arguments to pass if it does so.
1929 The return value of the modifier is what will be seen by the caller.
1933 =head2 Introspection
1937 =item B<< Class::MOP::Class->meta >>
1939 This will return a L<Class::MOP::Class> instance for this class.
1941 It should also be noted that L<Class::MOP> will actually bootstrap
1942 this module by installing a number of attribute meta-objects into its
1949 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1951 =head1 COPYRIGHT AND LICENSE
1953 Copyright 2006-2009 by Infinity Interactive, Inc.
1955 L<http://www.iinteractive.com>
1957 This library is free software; you can redistribute it and/or modify
1958 it under the same terms as Perl itself.