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', 'reftype', 'weaken';
14 use Sub::Name 'subname';
15 use Devel::GlobalDestruction 'in_global_destruction';
17 our $VERSION = '0.91';
18 $VERSION = eval $VERSION;
19 our $AUTHORITY = 'cpan:STEVAN';
21 use base 'Class::MOP::Module';
31 $package_name = shift;
34 $package_name = $options{package};
37 ($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 $meta->is_anon_class;
111 return Class::MOP::Class->initialize($class)->new_object(@_)
112 if $class ne __PACKAGE__;
114 my $options = @_ == 1 ? $_[0] : {@_};
117 # inherited from Class::MOP::Package
118 'package' => $options->{package},
121 # since the following attributes will
122 # actually be loaded from the symbol
123 # table, and actually bypass the instance
124 # entirely, we can just leave these things
125 # listed here for reference, because they
126 # should not actually have a value associated
128 'namespace' => \undef,
130 # inherited from Class::MOP::Module
132 'authority' => \undef,
134 # defined in Class::MOP::Class
135 'superclasses' => \undef,
139 'attribute_metaclass' =>
140 ( $options->{'attribute_metaclass'} || 'Class::MOP::Attribute' ),
141 'method_metaclass' =>
142 ( $options->{'method_metaclass'} || 'Class::MOP::Method' ),
143 'wrapped_method_metaclass' => (
144 $options->{'wrapped_method_metaclass'}
145 || 'Class::MOP::Method::Wrapped'
147 'instance_metaclass' =>
148 ( $options->{'instance_metaclass'} || 'Class::MOP::Instance' ),
149 'immutable_trait' => (
150 $options->{'immutable_trait'}
151 || 'Class::MOP::Class::Immutable::Trait'
153 'constructor_name' => ( $options->{constructor_name} || 'new' ),
154 'constructor_class' => (
155 $options->{constructor_class} || 'Class::MOP::Method::Constructor'
157 'destructor_class' => $options->{destructor_class},
161 sub reset_package_cache_flag { (shift)->{'_package_cache_flag'} = undef }
162 sub update_package_cache_flag {
165 # we can manually update the cache number
166 # since we are actually adding the method
167 # to our cache as well. This avoids us
168 # having to regenerate the method_map.
170 $self->{'_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name);
174 sub check_metaclass_compatibility {
175 Carp::cluck('The check_metaclass_compatibility method has been made private.'
176 . " The public version is deprecated and will be removed in a future release.\n");
177 shift->_check_metaclass_compatibility(@_);
180 sub _check_metaclass_compatibility {
183 # this is always okay ...
184 return if ref($self) eq 'Class::MOP::Class' &&
185 $self->instance_metaclass eq 'Class::MOP::Instance';
187 my @class_list = $self->linearized_isa;
188 shift @class_list; # shift off $self->name
190 foreach my $superclass_name (@class_list) {
191 my $super_meta = Class::MOP::get_metaclass_by_name($superclass_name) || next;
194 # we need to deal with the possibility
195 # of class immutability here, and then
196 # get the name of the class appropriately
198 = $super_meta->is_immutable
199 ? $super_meta->get_mutable_metaclass_name()
202 ($self->isa($super_meta_type))
203 || confess "The metaclass of " . $self->name . " ("
204 . (ref($self)) . ")" . " is not compatible with the " .
205 "metaclass of its superclass, ".$superclass_name . " ("
206 . ($super_meta_type) . ")";
208 # we also need to check that instance metaclasses
209 # are compatibile in the same the class.
210 ($self->instance_metaclass->isa($super_meta->instance_metaclass))
211 || confess "The instance metaclass for " . $self->name . " (" . ($self->instance_metaclass) . ")" .
212 " is not compatible with the " .
213 "instance metaclass of its superclass, " . $superclass_name . " (" . ($super_meta->instance_metaclass) . ")";
221 # this should be sufficient, if you have a
222 # use case where it is not, write a test and
224 my $ANON_CLASS_SERIAL = 0;
227 # we need a sufficiently annoying prefix
228 # this should suffice for now, this is
229 # used in a couple of places below, so
230 # need to put it up here for now.
231 my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
235 no warnings 'uninitialized';
236 $self->name =~ /^$ANON_CLASS_PREFIX/o;
239 sub create_anon_class {
240 my ($class, %options) = @_;
241 my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
242 return $class->create($package_name, %options);
246 # this will only get called for
247 # anon-classes, all other calls
248 # are assumed to occur during
249 # global destruction and so don't
250 # really need to be handled explicitly
254 return if in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated
256 no warnings 'uninitialized';
257 my $name = $self->name;
258 return unless $name =~ /^$ANON_CLASS_PREFIX/o;
259 # Moose does a weird thing where it replaces the metaclass for
260 # class when fixing metaclass incompatibility. In that case,
261 # we don't want to clean out the namespace now. We can detect
262 # that because Moose will explicitly update the singleton
263 # cache in Class::MOP.
264 my $current_meta = Class::MOP::get_metaclass_by_name($name);
265 return if $current_meta ne $self;
267 my ($serial_id) = ($name =~ /^$ANON_CLASS_PREFIX(\d+)/o);
269 @{$name . '::ISA'} = ();
270 %{$name . '::'} = ();
271 delete ${$ANON_CLASS_PREFIX}{$serial_id . '::'};
273 Class::MOP::remove_metaclass_by_name($name);
278 # creating classes with MOP ...
281 my ( $class, @args ) = @_;
283 unshift @args, 'package' if @args % 2 == 1;
285 my (%options) = @args;
286 my $package_name = $options{package};
288 (ref $options{superclasses} eq 'ARRAY')
289 || confess "You must pass an ARRAY ref of superclasses"
290 if exists $options{superclasses};
292 (ref $options{attributes} eq 'ARRAY')
293 || confess "You must pass an ARRAY ref of attributes"
294 if exists $options{attributes};
296 (ref $options{methods} eq 'HASH')
297 || confess "You must pass a HASH ref of methods"
298 if exists $options{methods};
300 my (%initialize_options) = @args;
301 delete @initialize_options{qw(
309 my $meta = $class->initialize( $package_name => %initialize_options );
311 $meta->_instantiate_module( $options{version}, $options{authority} );
314 $meta->add_method('meta' => sub {
315 $class->initialize(ref($_[0]) || $_[0]);
318 $meta->superclasses(@{$options{superclasses}})
319 if exists $options{superclasses};
321 # process attributes first, so that they can
322 # install accessors, but locally defined methods
323 # can then overwrite them. It is maybe a little odd, but
324 # I think this should be the order of things.
325 if (exists $options{attributes}) {
326 foreach my $attr (@{$options{attributes}}) {
327 $meta->add_attribute($attr);
330 if (exists $options{methods}) {
331 foreach my $method_name (keys %{$options{methods}}) {
332 $meta->add_method($method_name, $options{methods}->{$method_name});
341 # all these attribute readers will be bootstrapped
342 # away in the Class::MOP bootstrap section
344 sub get_attribute_map { $_[0]->{'attributes'} }
345 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
346 sub method_metaclass { $_[0]->{'method_metaclass'} }
347 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
348 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
349 sub immutable_trait { $_[0]->{'immutable_trait'} }
350 sub constructor_class { $_[0]->{'constructor_class'} }
351 sub constructor_name { $_[0]->{'constructor_name'} }
352 sub destructor_class { $_[0]->{'destructor_class'} }
354 sub _method_map { $_[0]->{'methods'} }
356 # Instance Construction & Cloning
362 # we need to protect the integrity of the
363 # Class::MOP::Class singletons here, so we
364 # delegate this to &construct_class_instance
365 # which will deal with the singletons
366 return $class->_construct_class_instance(@_)
367 if $class->name->isa('Class::MOP::Class');
368 return $class->_construct_instance(@_);
371 sub construct_instance {
372 Carp::cluck('The construct_instance method has been made private.'
373 . " The public version is deprecated and will be removed in a future release.\n");
374 shift->_construct_instance(@_);
377 sub _construct_instance {
379 my $params = @_ == 1 ? $_[0] : {@_};
380 my $meta_instance = $class->get_meta_instance();
382 # the code below is almost certainly incorrect
383 # but this is foreign inheritance, so we might
384 # have to kludge it in the end.
385 my $instance = $params->{__INSTANCE__} || $meta_instance->create_instance();
386 foreach my $attr ($class->get_all_attributes()) {
387 $attr->initialize_instance_slot($meta_instance, $instance, $params);
390 # this will only work for a HASH instance type
391 if ($class->is_anon_class) {
392 (reftype($instance) eq 'HASH')
393 || confess "Currently only HASH based instances are supported with instance of anon-classes";
395 # At some point we should make this official
396 # as a reserved slot name, but right now I am
397 # going to keep it here.
398 # my $RESERVED_MOP_SLOT = '__MOP__';
399 $instance->{'__MOP__'} = $class;
405 sub get_meta_instance {
407 $self->{'_meta_instance'} ||= $self->_create_meta_instance();
410 sub create_meta_instance {
411 Carp::cluck('The create_meta_instance method has been made private.'
412 . " The public version is deprecated and will be removed in a future release.\n");
413 shift->_create_meta_instance(@_);
416 sub _create_meta_instance {
419 my $instance = $self->instance_metaclass->new(
420 associated_metaclass => $self,
421 attributes => [ $self->get_all_attributes() ],
424 $self->add_meta_instance_dependencies()
425 if $instance->is_dependent_on_superclasses();
432 my $instance = shift;
433 (blessed($instance) && $instance->isa($class->name))
434 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
437 # we need to protect the integrity of the
438 # Class::MOP::Class singletons here, they
439 # should not be cloned.
440 return $instance if $instance->isa('Class::MOP::Class');
441 $class->_clone_instance($instance, @_);
445 Carp::cluck('The clone_instance method has been made private.'
446 . " The public version is deprecated and will be removed in a future release.\n");
447 shift->_clone_instance(@_);
450 sub _clone_instance {
451 my ($class, $instance, %params) = @_;
453 || confess "You can only clone instances, ($instance) is not a blessed instance";
454 my $meta_instance = $class->get_meta_instance();
455 my $clone = $meta_instance->clone_instance($instance);
456 foreach my $attr ($class->get_all_attributes()) {
457 if ( defined( my $init_arg = $attr->init_arg ) ) {
458 if (exists $params{$init_arg}) {
459 $attr->set_value($clone, $params{$init_arg});
466 sub rebless_instance {
467 my ($self, $instance, %params) = @_;
469 my $old_metaclass = Class::MOP::class_of($instance);
471 my $old_class = $old_metaclass ? $old_metaclass->name : blessed($instance);
472 $self->name->isa($old_class)
473 || confess "You may rebless only into a subclass of ($old_class), of which (". $self->name .") isn't.";
475 $old_metaclass->rebless_instance_away($instance, $self, %params)
478 my $meta_instance = $self->get_meta_instance();
481 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
482 $meta_instance->rebless_instance_structure($_[1], $self);
484 foreach my $attr ( $self->get_all_attributes ) {
485 if ( $attr->has_value($instance) ) {
486 if ( defined( my $init_arg = $attr->init_arg ) ) {
487 $params{$init_arg} = $attr->get_value($instance)
488 unless exists $params{$init_arg};
491 $attr->set_value($instance, $attr->get_value($instance));
496 foreach my $attr ($self->get_all_attributes) {
497 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
503 sub rebless_instance_away {
504 # this intentionally does nothing, it is just a hook
511 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' };
514 @{$self->get_package_symbol($var_spec)} = @supers;
517 # on 5.8 and below, we need to call
518 # a method to get Perl to detect
519 # a cycle in the class hierarchy
520 my $class = $self->name;
524 # we need to check the metaclass
525 # compatibility here so that we can
526 # be sure that the superclass is
527 # not potentially creating an issues
528 # we don't know about
530 $self->_check_metaclass_compatibility();
531 $self->_superclasses_updated();
533 @{$self->get_package_symbol($var_spec)};
536 sub _superclasses_updated {
538 $self->update_meta_instance_dependencies();
543 my $super_class = $self->name;
545 return @{ $super_class->mro::get_isarev() };
548 sub direct_subclasses {
550 my $super_class = $self->name;
555 } Class::MOP::Class->initialize($_)->superclasses
560 return @{ mro::get_linear_isa( (shift)->name ) };
563 sub class_precedence_list {
565 my $name = $self->name;
567 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
569 # We need to check for circular inheritance here
570 # if we are are not on 5.10, cause 5.8 detects it
571 # late. This will do nothing if all is well, and
572 # blow up otherwise. Yes, it's an ugly hack, better
573 # suggestions are welcome.
575 ($name || return)->isa('This is a test for circular inheritance')
578 # if our mro is c3, we can
579 # just grab the linear_isa
580 if (mro::get_mro($name) eq 'c3') {
581 return @{ mro::get_linear_isa($name) }
585 # we can't grab the linear_isa for dfs
586 # since it has all the duplicates
591 $self->initialize($_)->class_precedence_list()
592 } $self->superclasses()
599 sub wrap_method_body {
600 my ( $self, %args ) = @_;
602 ('CODE' eq ref $args{body})
603 || confess "Your code block must be a CODE reference";
605 $self->method_metaclass->wrap(
606 package_name => $self->name,
612 my ($self, $method_name, $method) = @_;
613 (defined $method_name && $method_name)
614 || confess "You must define a method name";
617 if (blessed($method)) {
618 $body = $method->body;
619 if ($method->package_name ne $self->name) {
620 $method = $method->clone(
621 package_name => $self->name,
623 ) if $method->can('clone');
626 $method->attach_to_class($self);
627 $self->_method_map->{$method_name} = $method;
630 # If a raw code reference is supplied, its method object is not created.
631 # The method object won't be created until required.
636 my ( $current_package, $current_name ) = Class::MOP::get_code_info($body);
638 if ( !defined $current_name || $current_name eq '__ANON__' ) {
639 my $full_method_name = ($self->name . '::' . $method_name);
640 subname($full_method_name => $body);
643 $self->add_package_symbol(
644 { sigil => '&', type => 'CODE', name => $method_name },
650 my $fetch_and_prepare_method = sub {
651 my ($self, $method_name) = @_;
652 my $wrapped_metaclass = $self->wrapped_method_metaclass;
654 my $method = $self->get_method($method_name);
655 # if we dont have local ...
657 # try to find the next method
658 $method = $self->find_next_method_by_name($method_name);
659 # die if it does not exist
661 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
662 # and now make sure to wrap it
663 # even if it is already wrapped
664 # because we need a new sub ref
665 $method = $wrapped_metaclass->wrap($method,
666 package_name => $self->name,
667 name => $method_name,
671 # now make sure we wrap it properly
672 $method = $wrapped_metaclass->wrap($method,
673 package_name => $self->name,
674 name => $method_name,
675 ) unless $method->isa($wrapped_metaclass);
677 $self->add_method($method_name => $method);
681 sub add_before_method_modifier {
682 my ($self, $method_name, $method_modifier) = @_;
683 (defined $method_name && $method_name)
684 || confess "You must pass in a method name";
685 my $method = $fetch_and_prepare_method->($self, $method_name);
686 $method->add_before_modifier(
687 subname(':before' => $method_modifier)
691 sub add_after_method_modifier {
692 my ($self, $method_name, $method_modifier) = @_;
693 (defined $method_name && $method_name)
694 || confess "You must pass in a method name";
695 my $method = $fetch_and_prepare_method->($self, $method_name);
696 $method->add_after_modifier(
697 subname(':after' => $method_modifier)
701 sub add_around_method_modifier {
702 my ($self, $method_name, $method_modifier) = @_;
703 (defined $method_name && $method_name)
704 || confess "You must pass in a method name";
705 my $method = $fetch_and_prepare_method->($self, $method_name);
706 $method->add_around_modifier(
707 subname(':around' => $method_modifier)
712 # the methods above used to be named like this:
713 # ${pkg}::${method}:(before|after|around)
714 # but this proved problematic when using one modifier
715 # to wrap multiple methods (something which is likely
716 # to happen pretty regularly IMO). So instead of naming
717 # it like this, I have chosen to just name them purely
718 # with their modifier names, like so:
719 # :(before|after|around)
720 # The fact is that in a stack trace, it will be fairly
721 # evident from the context what method they are attached
722 # to, and so don't need the fully qualified name.
726 Carp::cluck("The alias_method method is deprecated. Use add_method instead.\n");
728 shift->add_method(@_);
732 my ( $self, $code ) = @_;
734 my ( $code_package, $code_name ) = Class::MOP::get_code_info($code);
736 return $code_package && $code_package eq $self->name
737 || ( $code_package eq 'constant' && $code_name eq '__ANON__' );
741 my ($self, $method_name) = @_;
742 (defined $method_name && $method_name)
743 || confess "You must define a method name";
745 return defined($self->get_method($method_name));
749 my ($self, $method_name) = @_;
750 (defined $method_name && $method_name)
751 || confess "You must define a method name";
753 my $method_map = $self->_method_map;
754 my $method_object = $method_map->{$method_name};
755 my $code = $self->get_package_symbol({
756 name => $method_name,
761 unless ( $method_object && $method_object->body == ( $code || 0 ) ) {
762 if ( $code && $self->_code_is_mine($code) ) {
763 $method_object = $method_map->{$method_name}
764 = $self->wrap_method_body(
766 name => $method_name,
767 associated_metaclass => $self,
771 delete $method_map->{$method_name};
776 return $method_object;
780 my ($self, $method_name) = @_;
781 (defined $method_name && $method_name)
782 || confess "You must define a method name";
784 my $removed_method = delete $self->get_method_map->{$method_name};
786 $self->remove_package_symbol(
787 { sigil => '&', type => 'CODE', name => $method_name }
790 $removed_method->detach_from_class if $removed_method;
792 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
794 return $removed_method;
797 sub get_method_list {
799 return grep { $self->has_method($_) } keys %{ $self->namespace };
802 sub find_method_by_name {
803 my ($self, $method_name) = @_;
804 (defined $method_name && $method_name)
805 || confess "You must define a method name to find";
806 foreach my $class ($self->linearized_isa) {
807 my $method = $self->initialize($class)->get_method($method_name);
808 return $method if defined $method;
813 sub get_all_methods {
815 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
816 return values %methods;
819 sub compute_all_applicable_methods {
820 Carp::cluck('The compute_all_applicable_methods method is deprecated.'
821 . " Use get_all_methods instead.\n");
826 class => $_->package_name,
827 code => $_, # sigh, overloading
829 } shift->get_all_methods(@_);
832 sub get_all_method_names {
835 return grep { !$uniq{$_}++ } map { $self->initialize($_)->get_method_list } $self->linearized_isa;
838 sub find_all_methods_by_name {
839 my ($self, $method_name) = @_;
840 (defined $method_name && $method_name)
841 || confess "You must define a method name to find";
843 foreach my $class ($self->linearized_isa) {
844 # fetch the meta-class ...
845 my $meta = $self->initialize($class);
847 name => $method_name,
849 code => $meta->get_method($method_name)
850 } if $meta->has_method($method_name);
855 sub find_next_method_by_name {
856 my ($self, $method_name) = @_;
857 (defined $method_name && $method_name)
858 || confess "You must define a method name to find";
859 my @cpl = $self->linearized_isa;
860 shift @cpl; # discard ourselves
861 foreach my $class (@cpl) {
862 my $method = $self->initialize($class)->get_method($method_name);
863 return $method if defined $method;
872 # either we have an attribute object already
873 # or we need to create one from the args provided
874 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
875 # make sure it is derived from the correct type though
876 ($attribute->isa('Class::MOP::Attribute'))
877 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
879 # first we attach our new attribute
880 # because it might need certain information
881 # about the class which it is attached to
882 $attribute->attach_to_class($self);
884 my $attr_name = $attribute->name;
886 # then we remove attributes of a conflicting
887 # name here so that we can properly detach
888 # the old attr object, and remove any
889 # accessors it would have generated
890 if ( $self->has_attribute($attr_name) ) {
891 $self->remove_attribute($attr_name);
893 $self->invalidate_meta_instances();
896 # get our count of previously inserted attributes and
897 # increment by one so this attribute knows its order
898 my $order = (scalar keys %{$self->get_attribute_map});
899 $attribute->_set_insertion_order($order);
901 # then onto installing the new accessors
902 $self->get_attribute_map->{$attr_name} = $attribute;
904 # invalidate package flag here
908 eval { $attribute->install_accessors() };
912 $self->remove_attribute($attr_name);
919 sub update_meta_instance_dependencies {
922 if ( $self->{meta_instance_dependencies} ) {
923 return $self->add_meta_instance_dependencies;
927 sub add_meta_instance_dependencies {
930 $self->remove_meta_instance_dependencies;
932 my @attrs = $self->get_all_attributes();
935 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
937 foreach my $class ( @classes ) {
938 $class->add_dependent_meta_instance($self);
941 $self->{meta_instance_dependencies} = \@classes;
944 sub remove_meta_instance_dependencies {
947 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
948 foreach my $class ( @$classes ) {
949 $class->remove_dependent_meta_instance($self);
959 sub add_dependent_meta_instance {
960 my ( $self, $metaclass ) = @_;
961 push @{ $self->{dependent_meta_instances} }, $metaclass;
964 sub remove_dependent_meta_instance {
965 my ( $self, $metaclass ) = @_;
966 my $name = $metaclass->name;
967 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
970 sub invalidate_meta_instances {
972 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
975 sub invalidate_meta_instance {
977 undef $self->{_meta_instance};
981 my ($self, $attribute_name) = @_;
982 (defined $attribute_name && $attribute_name)
983 || confess "You must define an attribute name";
984 exists $self->get_attribute_map->{$attribute_name};
988 my ($self, $attribute_name) = @_;
989 (defined $attribute_name && $attribute_name)
990 || confess "You must define an attribute name";
991 return $self->get_attribute_map->{$attribute_name}
993 # this will return undef anyway, so no need ...
994 # if $self->has_attribute($attribute_name);
998 sub remove_attribute {
999 my ($self, $attribute_name) = @_;
1000 (defined $attribute_name && $attribute_name)
1001 || confess "You must define an attribute name";
1002 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
1003 return unless defined $removed_attribute;
1004 delete $self->get_attribute_map->{$attribute_name};
1005 $self->invalidate_meta_instances();
1006 $removed_attribute->remove_accessors();
1007 $removed_attribute->detach_from_class();
1008 return $removed_attribute;
1011 sub get_attribute_list {
1013 keys %{$self->get_attribute_map};
1016 sub get_all_attributes {
1018 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
1019 return values %attrs;
1022 sub compute_all_applicable_attributes {
1023 Carp::cluck('The compute_all_applicable_attributes method has been deprecated.'
1024 . " Use get_all_attributes instead.\n");
1026 shift->get_all_attributes(@_);
1029 sub find_attribute_by_name {
1030 my ($self, $attr_name) = @_;
1031 foreach my $class ($self->linearized_isa) {
1032 # fetch the meta-class ...
1033 my $meta = $self->initialize($class);
1034 return $meta->get_attribute($attr_name)
1035 if $meta->has_attribute($attr_name);
1040 # check if we can reinitialize
1044 # if any local attr is defined
1045 return if $self->get_attribute_list;
1047 # or any non-declared methods
1048 if ( my @methods = values %{ $self->get_method_map } ) {
1049 my $metaclass = $self->method_metaclass;
1050 foreach my $method ( @methods ) {
1051 return if $method->isa("Class::MOP::Method::Generated");
1052 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1061 sub is_mutable { 1 }
1062 sub is_immutable { 0 }
1064 sub _immutable_options {
1065 my ( $self, @args ) = @_;
1068 inline_accessors => 1,
1069 inline_constructor => 1,
1070 inline_destructor => 0,
1072 immutable_trait => $self->immutable_trait,
1073 constructor_name => $self->constructor_name,
1074 constructor_class => $self->constructor_class,
1075 destructor_class => $self->destructor_class,
1080 sub make_immutable {
1081 my ( $self, @args ) = @_;
1083 if ( $self->is_mutable ) {
1084 $self->_initialize_immutable( $self->_immutable_options(@args) );
1085 $self->_rebless_as_immutable(@args);
1096 if ( $self->is_immutable ) {
1097 my @args = $self->immutable_options;
1098 $self->_rebless_as_mutable();
1099 $self->_remove_inlined_code(@args);
1100 delete $self->{__immutable};
1108 sub _rebless_as_immutable {
1109 my ( $self, @args ) = @_;
1111 $self->{__immutable}{original_class} = ref $self;
1113 bless $self => $self->_immutable_metaclass(@args);
1116 sub _immutable_metaclass {
1117 my ( $self, %args ) = @_;
1119 if ( my $class = $args{immutable_metaclass} ) {
1123 my $trait = $args{immutable_trait} = $self->immutable_trait
1124 || confess "no immutable trait specified for $self";
1126 my $meta = $self->meta;
1127 my $meta_attr = $meta->find_attribute_by_name("immutable_trait");
1131 if ( $meta_attr and $trait eq $meta_attr->default ) {
1132 # if the trait is the same as the default we try and pick a
1133 # predictable name for the immutable metaclass
1134 $class_name = 'Class::MOP::Class::Immutable::' . ref($self);
1137 $class_name = join '::', 'Class::MOP::Class::Immutable::CustomTrait',
1138 $trait, 'ForMetaClass', ref($self);
1142 if Class::MOP::is_class_loaded($class_name);
1144 # If the metaclass is a subclass of CMOP::Class which has had
1145 # metaclass roles applied (via Moose), then we want to make sure
1146 # that we preserve that anonymous class (see Fey::ORM for an
1147 # example of where this matters).
1149 = $meta->is_immutable
1150 ? $meta->get_mutable_metaclass_name
1153 my $immutable_meta = $meta_name->create(
1155 superclasses => [ ref $self ],
1158 Class::MOP::load_class($trait);
1159 for my $meth ( Class::MOP::Class->initialize($trait)->get_all_methods ) {
1160 my $meth_name = $meth->name;
1162 if ( $immutable_meta->find_method_by_name( $meth_name ) ) {
1163 $immutable_meta->add_around_method_modifier( $meth_name, $meth->body );
1166 $immutable_meta->add_method( $meth_name, $meth->clone );
1170 $immutable_meta->make_immutable(
1171 inline_constructor => 0,
1172 inline_accessors => 0,
1178 sub _remove_inlined_code {
1181 $self->remove_method( $_->name ) for $self->_inlined_methods;
1183 delete $self->{__immutable}{inlined_methods};
1186 sub _inlined_methods { @{ $_[0]{__immutable}{inlined_methods} || [] } }
1188 sub _add_inlined_method {
1189 my ( $self, $method ) = @_;
1191 push @{ $self->{__immutable}{inlined_methods} ||= [] }, $method;
1194 sub _initialize_immutable {
1195 my ( $self, %args ) = @_;
1197 $self->{__immutable}{options} = \%args;
1198 $self->_install_inlined_code(%args);
1201 sub _install_inlined_code {
1202 my ( $self, %args ) = @_;
1205 $self->_inline_accessors(%args) if $args{inline_accessors};
1206 $self->_inline_constructor(%args) if $args{inline_constructor};
1207 $self->_inline_destructor(%args) if $args{inline_destructor};
1210 sub _rebless_as_mutable {
1213 bless $self, $self->get_mutable_metaclass_name;
1218 sub _inline_accessors {
1221 foreach my $attr_name ( $self->get_attribute_list ) {
1222 $self->get_attribute($attr_name)->install_accessors(1);
1226 sub _inline_constructor {
1227 my ( $self, %args ) = @_;
1229 my $name = $args{constructor_name};
1231 if ( $self->has_method($name) && !$args{replace_constructor} ) {
1232 my $class = $self->name;
1233 warn "Not inlining a constructor for $class since it defines"
1234 . " its own constructor.\n"
1235 . "If you are certain you don't need to inline your"
1236 . " constructor, specify inline_constructor => 0 in your"
1237 . " call to $class->meta->make_immutable\n";
1241 my $constructor_class = $args{constructor_class};
1243 Class::MOP::load_class($constructor_class);
1245 my $constructor = $constructor_class->new(
1249 package_name => $self->name,
1253 if ( $args{replace_constructor} or $constructor->can_be_inlined ) {
1254 $self->add_method( $name => $constructor );
1255 $self->_add_inlined_method($constructor);
1259 sub _inline_destructor {
1260 my ( $self, %args ) = @_;
1262 ( exists $args{destructor_class} && defined $args{destructor_class} )
1263 || confess "The 'inline_destructor' option is present, but "
1264 . "no destructor class was specified";
1266 if ( $self->has_method('DESTROY') && ! $args{replace_destructor} ) {
1267 my $class = $self->name;
1268 warn "Not inlining a destructor for $class since it defines"
1269 . " its own destructor.\n";
1273 my $destructor_class = $args{destructor_class};
1275 Class::MOP::load_class($destructor_class);
1277 return unless $destructor_class->is_needed($self);
1279 my $destructor = $destructor_class->new(
1282 package_name => $self->name,
1286 if ( $args{replace_destructor} or $destructor->can_be_inlined ) {
1287 $self->add_method( 'DESTROY' => $destructor );
1288 $self->_add_inlined_method($destructor);
1300 Class::MOP::Class - Class Meta Object
1304 # assuming that class Foo
1305 # has been defined, you can
1307 # use this for introspection ...
1309 # add a method to Foo ...
1310 Foo->meta->add_method( 'bar' => sub {...} )
1312 # get a list of all the classes searched
1313 # the method dispatcher in the correct order
1314 Foo->meta->class_precedence_list()
1316 # remove a method from Foo
1317 Foo->meta->remove_method('bar');
1319 # or use this to actually create classes ...
1321 Class::MOP::Class->create(
1324 superclasses => ['Foo'],
1326 Class::MOP::Attribute->new('$bar'),
1327 Class::MOP::Attribute->new('$baz'),
1330 calculate_bar => sub {...},
1331 construct_baz => sub {...}
1338 The Class Protocol is the largest and most complex part of the
1339 Class::MOP meta-object protocol. It controls the introspection and
1340 manipulation of Perl 5 classes, and it can create them as well. The
1341 best way to understand what this module can do, is to read the
1342 documentation for each of its methods.
1346 C<Class::MOP::Class> is a subclass of L<Class::MOP::Module>.
1350 =head2 Class construction
1352 These methods all create new C<Class::MOP::Class> objects. These
1353 objects can represent existing classes, or they can be used to create
1354 new classes from scratch.
1356 The metaclass object for a given class is a singleton. If you attempt
1357 to create a metaclass for the same class twice, you will just get the
1362 =item B<< Class::MOP::Class->create($package_name, %options) >>
1364 This method creates a new C<Class::MOP::Class> object with the given
1365 package name. It accepts a number of options.
1371 An optional version number for the newly created package.
1375 An optional authority for the newly created package.
1377 =item * superclasses
1379 An optional array reference of superclass names.
1383 An optional hash reference of methods for the class. The keys of the
1384 hash reference are method names, and values are subroutine references.
1388 An optional array reference of L<Class::MOP::Attribute> objects.
1392 =item B<< Class::MOP::Class->create_anon_class(%options) >>
1394 This method works just like C<< Class::MOP::Class->create >> but it
1395 creates an "anonymous" class. In fact, the class does have a name, but
1396 that name is a unique name generated internally by this module.
1398 It accepts the same C<superclasses>, C<methods>, and C<attributes>
1399 parameters that C<create> accepts.
1401 Anonymous classes are destroyed once the metaclass they are attached
1402 to goes out of scope, and will be removed from Perl's internal symbol
1405 All instances of an anonymous class keep a special reference to the
1406 metaclass object, which prevents the metaclass from going out of scope
1407 while any instances exist.
1409 This only works if the instance if based on a hash reference, however.
1411 =item B<< Class::MOP::Class->initialize($package_name, %options) >>
1413 This method will initialize a C<Class::MOP::Class> object for the
1414 named package. Unlike C<create>, this method I<will not> create a new
1417 The purpose of this method is to retrieve a C<Class::MOP::Class>
1418 object for introspecting an existing class.
1420 If an existing C<Class::MOP::Class> object exists for the named
1421 package, it will be returned, and any options provided will be
1424 If the object does not yet exist, it will be created.
1426 The valid options that can be passed to this method are
1427 C<attribute_metaclass>, C<method_metaclass>,
1428 C<wrapped_method_metaclass>, and C<instance_metaclass>. These are all
1429 optional, and default to the appropriate class in the C<Class::MOP>
1434 =head2 Object instance construction and cloning
1436 These methods are all related to creating and/or cloning object
1441 =item B<< $metaclass->clone_object($instance, %params) >>
1443 This method clones an existing object instance. Any parameters you
1444 provide are will override existing attribute values in the object.
1446 This is a convenience method for cloning an object instance, then
1447 blessing it into the appropriate package.
1449 You could implement a clone method in your class, using this method:
1452 my ($self, %params) = @_;
1453 $self->meta->clone_object($self, %params);
1456 =item B<< $metaclass->rebless_instance($instance, %params) >>
1458 This method changes the class of C<$instance> to the metaclass's class.
1460 You can only rebless an instance into a subclass of its current
1461 class. If you pass any additional parameters, these will be treated
1462 like constructor parameters and used to initialize the object's
1463 attributes. Any existing attributes that are already set will be
1466 Before reblessing the instance, this method will call
1467 C<rebless_instance_away> on the instance's current metaclass. This method
1468 will be passed the instance, the new metaclass, and any parameters
1469 specified to C<rebless_instance>. By default, C<rebless_instance_away>
1470 does nothing; it is merely a hook.
1472 =item B<< $metaclass->new_object(%params) >>
1474 This method is used to create a new object of the metaclass's
1475 class. Any parameters you provide are used to initialize the
1476 instance's attributes. A special C<__INSTANCE__> key can be passed to
1477 provide an already generated instance, rather than having Class::MOP
1478 generate it for you. This is mostly useful for using Class::MOP with
1479 foreign classes, which generally generate instances using their own
1482 =item B<< $metaclass->instance_metaclass >>
1484 Returns the class name of the instance metaclass, see
1485 L<Class::MOP::Instance> for more information on the instance
1488 =item B<< $metaclass->get_meta_instance >>
1490 Returns an instance of the C<instance_metaclass> to be used in the
1491 construction of a new instance of the class.
1495 =head2 Informational predicates
1497 These are a few predicate methods for asking information about the
1502 =item B<< $metaclass->is_anon_class >>
1504 This returns true if the class was created by calling C<<
1505 Class::MOP::Class->create_anon_class >>.
1507 =item B<< $metaclass->is_mutable >>
1509 This returns true if the class is still mutable.
1511 =item B<< $metaclass->is_immutable >>
1513 This returns true if the class has been made immutable.
1515 =item B<< $metaclass->is_pristine >>
1517 A class is I<not> pristine if it has non-inherited attributes or if it
1518 has any generated methods.
1522 =head2 Inheritance Relationships
1526 =item B<< $metaclass->superclasses(@superclasses) >>
1528 This is a read-write accessor which represents the superclass
1529 relationships of the metaclass's class.
1531 This is basically sugar around getting and setting C<@ISA>.
1533 =item B<< $metaclass->class_precedence_list >>
1535 This returns a list of all of the class's ancestor classes. The
1536 classes are returned in method dispatch order.
1538 =item B<< $metaclass->linearized_isa >>
1540 This returns a list based on C<class_precedence_list> but with all
1543 =item B<< $metaclass->subclasses >>
1545 This returns a list of all subclasses for this class, even indirect
1548 =item B<< $metaclass->direct_subclasses >>
1550 This returns a list of immediate subclasses for this class, which does not
1551 include indirect subclasses.
1555 =head2 Method introspection and creation
1557 These methods allow you to introspect a class's methods, as well as
1558 add, remove, or change methods.
1560 Determining what is truly a method in a Perl 5 class requires some
1561 heuristics (aka guessing).
1563 Methods defined outside the package with a fully qualified name (C<sub
1564 Package::name { ... }>) will be included. Similarly, methods named
1565 with a fully qualified name using L<Sub::Name> are also included.
1567 However, we attempt to ignore imported functions.
1569 Ultimately, we are using heuristics to determine what truly is a
1570 method in a class, and these heuristics may get the wrong answer in
1571 some edge cases. However, for most "normal" cases the heuristics work
1576 =item B<< $metaclass->get_method($method_name) >>
1578 This will return a L<Class::MOP::Method> for the specified
1579 C<$method_name>. If the class does not have the specified method, it
1582 =item B<< $metaclass->has_method($method_name) >>
1584 Returns a boolean indicating whether or not the class defines the
1585 named method. It does not include methods inherited from parent
1588 =item B<< $metaclass->get_method_map >>
1590 Returns a hash reference representing the methods defined in this
1591 class. The keys are method names and the values are
1592 L<Class::MOP::Method> objects.
1594 =item B<< $metaclass->get_method_list >>
1596 This will return a list of method I<names> for all methods defined in
1599 =item B<< $metaclass->get_all_methods >>
1601 This will traverse the inheritance hierarchy and return a list of all
1602 the L<Class::MOP::Method> objects for this class and its parents.
1604 =item B<< $metaclass->find_method_by_name($method_name) >>
1606 This will return a L<Class::MOP::Method> for the specified
1607 C<$method_name>. If the class does not have the specified method, it
1610 Unlike C<get_method>, this method I<will> look for the named method in
1613 =item B<< $metaclass->get_all_method_names >>
1615 This will return a list of method I<names> for all of this class's
1616 methods, including inherited methods.
1618 =item B<< $metaclass->find_all_methods_by_name($method_name) >>
1620 This method looks for the named method in the class and all of its
1621 parents. It returns every matching method it finds in the inheritance
1622 tree, so it returns a list of methods.
1624 Each method is returned as a hash reference with three keys. The keys
1625 are C<name>, C<class>, and C<code>. The C<code> key has a
1626 L<Class::MOP::Method> object as its value.
1628 The list of methods is distinct.
1630 =item B<< $metaclass->find_next_method_by_name($method_name) >>
1632 This method returns the first method in any superclass matching the
1633 given name. It is effectively the method that C<SUPER::$method_name>
1636 =item B<< $metaclass->add_method($method_name, $method) >>
1638 This method takes a method name and a subroutine reference, and adds
1639 the method to the class.
1641 The subroutine reference can be a L<Class::MOP::Method>, and you are
1642 strongly encouraged to pass a meta method object instead of a code
1643 reference. If you do so, that object gets stored as part of the
1644 class's method map directly. If not, the meta information will have to
1645 be recreated later, and may be incorrect.
1647 If you provide a method object, this method will clone that object if
1648 the object's package name does not match the class name. This lets us
1649 track the original source of any methods added from other classes
1650 (notably Moose roles).
1652 =item B<< $metaclass->remove_method($method_name) >>
1654 Remove the named method from the class. This method returns the
1655 L<Class::MOP::Method> object for the method.
1657 =item B<< $metaclass->method_metaclass >>
1659 Returns the class name of the method metaclass, see
1660 L<Class::MOP::Method> for more information on the method metaclass.
1662 =item B<< $metaclass->wrapped_method_metaclass >>
1664 Returns the class name of the wrapped method metaclass, see
1665 L<Class::MOP::Method::Wrapped> for more information on the wrapped
1670 =head2 Attribute introspection and creation
1672 Because Perl 5 does not have a core concept of attributes in classes,
1673 we can only return information about attributes which have been added
1674 via this class's methods. We cannot discover information about
1675 attributes which are defined in terms of "regular" Perl 5 methods.
1679 =item B<< $metaclass->get_attribute($attribute_name) >>
1681 This will return a L<Class::MOP::Attribute> for the specified
1682 C<$attribute_name>. If the class does not have the specified
1683 attribute, it returns C<undef>.
1685 NOTE that get_attribute does not search superclasses, for that you
1686 need to use C<find_attribute_by_name>.
1688 =item B<< $metaclass->has_attribute($attribute_name) >>
1690 Returns a boolean indicating whether or not the class defines the
1691 named attribute. It does not include attributes inherited from parent
1694 =item B<< $metaclass->get_attribute_map >>
1696 Returns a hash reference representing the attributes defined in this
1697 class. The keys are attribute names and the values are
1698 L<Class::MOP::Attribute> objects.
1700 =item B<< $metaclass->get_attribute_list >>
1702 This will return a list of attributes I<names> for all attributes
1703 defined in this class.
1705 =item B<< $metaclass->get_all_attributes >>
1707 This will traverse the inheritance hierarchy and return a list of all
1708 the L<Class::MOP::Attribute> objects for this class and its parents.
1710 =item B<< $metaclass->find_attribute_by_name($attribute_name) >>
1712 This will return a L<Class::MOP::Attribute> for the specified
1713 C<$attribute_name>. If the class does not have the specified
1714 attribute, it returns C<undef>
1716 Unlike C<get_attribute>, this attribute I<will> look for the named
1717 attribute in superclasses.
1719 =item B<< $metaclass->add_attribute(...) >>
1721 This method accepts either an existing L<Class::MOP::Attribute>
1722 object, or parameters suitable for passing to that class's C<new>
1725 The attribute provided will be added to the class.
1727 Any accessor methods defined by the attribute will be added to the
1728 class when the attribute is added.
1730 If an attribute of the same name already exists, the old attribute
1731 will be removed first.
1733 =item B<< $metaclass->remove_attribute($attribute_name) >>
1735 This will remove the named attribute from the class, and
1736 L<Class::MOP::Attribute> object.
1738 Removing an attribute also removes any accessor methods defined by the
1741 However, note that removing an attribute will only affect I<future>
1742 object instances created for this class, not existing instances.
1744 =item B<< $metaclass->attribute_metaclass >>
1746 Returns the class name of the attribute metaclass for this class. By
1747 default, this is L<Class::MOP::Attribute>. for more information on
1751 =head2 Class Immutability
1753 Making a class immutable "freezes" the class definition. You can no
1754 longer call methods which alter the class, such as adding or removing
1755 methods or attributes.
1757 Making a class immutable lets us optimize the class by inlining some
1758 methods, and also allows us to optimize some methods on the metaclass
1761 After immutabilization, the metaclass object will cache most
1762 informational methods such as C<get_method_map> and
1763 C<get_all_attributes>. Methods which would alter the class, such as
1764 C<add_attribute>, C<add_method>, and so on will throw an error on an
1765 immutable metaclass object.
1767 The immutabilization system in L<Moose> takes much greater advantage
1768 of the inlining features than Class::MOP itself does.
1772 =item B<< $metaclass->make_immutable(%options) >>
1774 This method will create an immutable transformer and uses it to make
1775 the class and its metaclass object immutable.
1777 This method accepts the following options:
1781 =item * inline_accessors
1783 =item * inline_constructor
1785 =item * inline_destructor
1787 These are all booleans indicating whether the specified method(s)
1790 By default, accessors and the constructor are inlined, but not the
1793 =item * immutable_trait
1795 The name of a class which will be used as a parent class for the
1796 metaclass object being made immutable. This "trait" implements the
1797 post-immutability functionality of the metaclass (but not the
1798 transformation itself).
1800 This defaults to L<Class::MOP::Class::Immutable::Trait>.
1802 =item * constructor_name
1804 This is the constructor method name. This defaults to "new".
1806 =item * constructor_class
1808 The name of the method metaclass for constructors. It will be used to
1809 generate the inlined constructor. This defaults to
1810 "Class::MOP::Method::Constructor".
1812 =item * replace_constructor
1814 This is a boolean indicating whether an existing constructor should be
1815 replaced when inlining a constructor. This defaults to false.
1817 =item * destructor_class
1819 The name of the method metaclass for destructors. It will be used to
1820 generate the inlined destructor. This defaults to
1821 "Class::MOP::Method::Denstructor".
1823 =item * replace_destructor
1825 This is a boolean indicating whether an existing destructor should be
1826 replaced when inlining a destructor. This defaults to false.
1830 =item B<< $metaclass->make_mutable >>
1832 Calling this method reverse the immutabilization transformation.
1836 =head2 Method Modifiers
1838 Method modifiers are hooks which allow a method to be wrapped with
1839 I<before>, I<after> and I<around> method modifiers. Every time a
1840 method is called, it's modifiers are also called.
1842 A class can modify its own methods, as well as methods defined in
1845 =head3 How method modifiers work?
1847 Method modifiers work by wrapping the original method and then
1848 replacing it in the class's symbol table. The wrappers will handle
1849 calling all the modifiers in the appropriate order and preserving the
1850 calling context for the original method.
1852 The return values of C<before> and C<after> modifiers are
1853 ignored. This is because their purpose is B<not> to filter the input
1854 and output of the primary method (this is done with an I<around>
1857 This may seem like an odd restriction to some, but doing this allows
1858 for simple code to be added at the beginning or end of a method call
1859 without altering the function of the wrapped method or placing any
1860 extra responsibility on the code of the modifier.
1862 Of course if you have more complex needs, you can use the C<around>
1863 modifier which allows you to change both the parameters passed to the
1864 wrapped method, as well as its return value.
1866 Before and around modifiers are called in last-defined-first-called
1867 order, while after modifiers are called in first-defined-first-called
1868 order. So the call tree might looks something like this:
1880 =head3 What is the performance impact?
1882 Of course there is a performance cost associated with method
1883 modifiers, but we have made every effort to make that cost directly
1884 proportional to the number of modifier features you utilize.
1886 The wrapping method does it's best to B<only> do as much work as it
1887 absolutely needs to. In order to do this we have moved some of the
1888 performance costs to set-up time, where they are easier to amortize.
1890 All this said, our benchmarks have indicated the following:
1892 simple wrapper with no modifiers 100% slower
1893 simple wrapper with simple before modifier 400% slower
1894 simple wrapper with simple after modifier 450% slower
1895 simple wrapper with simple around modifier 500-550% slower
1896 simple wrapper with all 3 modifiers 1100% slower
1898 These numbers may seem daunting, but you must remember, every feature
1899 comes with some cost. To put things in perspective, just doing a
1900 simple C<AUTOLOAD> which does nothing but extract the name of the
1901 method called and return it costs about 400% over a normal method
1906 =item B<< $metaclass->add_before_method_modifier($method_name, $code) >>
1908 This wraps the specified method with the supplied subroutine
1909 reference. The modifier will be called as a method itself, and will
1910 receive the same arguments as are passed to the method.
1912 When the modifier exits, the wrapped method will be called.
1914 The return value of the modifier will be ignored.
1916 =item B<< $metaclass->add_after_method_modifier($method_name, $code) >>
1918 This wraps the specified method with the supplied subroutine
1919 reference. The modifier will be called as a method itself, and will
1920 receive the same arguments as are passed to the method.
1922 When the wrapped methods exits, the modifier will be called.
1924 The return value of the modifier will be ignored.
1926 =item B<< $metaclass->add_around_method_modifier($method_name, $code) >>
1928 This wraps the specified method with the supplied subroutine
1931 The first argument passed to the modifier will be a subroutine
1932 reference to the wrapped method. The second argument is the object,
1933 and after that come any arguments passed when the method is called.
1935 The around modifier can choose to call the original method, as well as
1936 what arguments to pass if it does so.
1938 The return value of the modifier is what will be seen by the caller.
1942 =head2 Introspection
1946 =item B<< Class::MOP::Class->meta >>
1948 This will return a L<Class::MOP::Class> instance for this class.
1950 It should also be noted that L<Class::MOP> will actually bootstrap
1951 this module by installing a number of attribute meta-objects into its
1958 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1960 =head1 COPYRIGHT AND LICENSE
1962 Copyright 2006-2009 by Infinity Interactive, Inc.
1964 L<http://www.iinteractive.com>
1966 This library is free software; you can redistribute it and/or modify
1967 it under the same terms as Perl itself.