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 = '0.89';
18 $VERSION = eval $VERSION;
19 our $AUTHORITY = 'cpan:STEVAN';
21 use base 'Class::MOP::Module';
31 $package_name = shift;
34 $package_name = $options{package};
37 ($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 $self;
268 @{$self->get_package_symbol({name => 'ISA', type => 'ARRAY', sigil => '$', create => 1 })} = ();
269 %{ $self->namespace } = ();
271 my ($serial_id) = ($name =~ /^$ANON_CLASS_PREFIX(\d+)/o);
273 Class::MOP::remove_metaclass_by_name($name);
276 delete ${$ANON_CLASS_PREFIX}{$serial_id . '::'};
282 # creating classes with MOP ...
285 my ( $class, @args ) = @_;
287 unshift @args, 'package' if @args % 2 == 1;
289 my (%options) = @args;
290 my $package_name = $options{package};
292 (ref $options{superclasses} eq 'ARRAY')
293 || confess "You must pass an ARRAY ref of superclasses"
294 if exists $options{superclasses};
296 (ref $options{attributes} eq 'ARRAY')
297 || confess "You must pass an ARRAY ref of attributes"
298 if exists $options{attributes};
300 (ref $options{methods} eq 'HASH')
301 || confess "You must pass a HASH ref of methods"
302 if exists $options{methods};
304 my (%initialize_options) = @args;
305 delete @initialize_options{qw(
313 my $meta = $class->initialize( $package_name => %initialize_options );
315 $meta->_instantiate_module( $options{version}, $options{authority} );
318 $meta->add_method('meta' => sub {
319 $class->initialize(ref($_[0]) || $_[0]);
322 $meta->superclasses(@{$options{superclasses}})
323 if exists $options{superclasses};
325 # process attributes first, so that they can
326 # install accessors, but locally defined methods
327 # can then overwrite them. It is maybe a little odd, but
328 # I think this should be the order of things.
329 if (exists $options{attributes}) {
330 foreach my $attr (@{$options{attributes}}) {
331 $meta->add_attribute($attr);
334 if (exists $options{methods}) {
335 foreach my $method_name (keys %{$options{methods}}) {
336 $meta->add_method($method_name, $options{methods}->{$method_name});
345 # all these attribute readers will be bootstrapped
346 # away in the Class::MOP bootstrap section
348 sub get_attribute_map { $_[0]->{'attributes'} }
349 sub attribute_metaclass { $_[0]->{'attribute_metaclass'} }
350 sub method_metaclass { $_[0]->{'method_metaclass'} }
351 sub wrapped_method_metaclass { $_[0]->{'wrapped_method_metaclass'} }
352 sub instance_metaclass { $_[0]->{'instance_metaclass'} }
353 sub immutable_trait { $_[0]->{'immutable_trait'} }
354 sub constructor_class { $_[0]->{'constructor_class'} }
355 sub constructor_name { $_[0]->{'constructor_name'} }
356 sub destructor_class { $_[0]->{'destructor_class'} }
358 sub _method_map { $_[0]->{'methods'} }
360 # Instance Construction & Cloning
366 # we need to protect the integrity of the
367 # Class::MOP::Class singletons here, so we
368 # delegate this to &construct_class_instance
369 # which will deal with the singletons
370 return $class->_construct_class_instance(@_)
371 if $class->name->isa('Class::MOP::Class');
372 return $class->_construct_instance(@_);
375 sub construct_instance {
376 Carp::cluck('The construct_instance method has been made private.'
377 . " The public version is deprecated and will be removed in a future release.\n");
378 shift->_construct_instance(@_);
381 sub _construct_instance {
383 my $params = @_ == 1 ? $_[0] : {@_};
384 my $meta_instance = $class->get_meta_instance();
386 # the code below is almost certainly incorrect
387 # but this is foreign inheritance, so we might
388 # have to kludge it in the end.
389 my $instance = $params->{__INSTANCE__} || $meta_instance->create_instance();
390 foreach my $attr ($class->get_all_attributes()) {
391 $attr->initialize_instance_slot($meta_instance, $instance, $params);
394 # this will only work for a HASH instance type
395 if ($class->is_anon_class) {
396 (reftype($instance) eq 'HASH')
397 || confess "Currently only HASH based instances are supported with instance of anon-classes";
399 # At some point we should make this official
400 # as a reserved slot name, but right now I am
401 # going to keep it here.
402 # my $RESERVED_MOP_SLOT = '__MOP__';
403 $instance->{'__MOP__'} = $class;
409 sub get_meta_instance {
411 $self->{'_meta_instance'} ||= $self->_create_meta_instance();
414 sub create_meta_instance {
415 Carp::cluck('The create_meta_instance method has been made private.'
416 . " The public version is deprecated and will be removed in a future release.\n");
417 shift->_create_meta_instance(@_);
420 sub _create_meta_instance {
423 my $instance = $self->instance_metaclass->new(
424 associated_metaclass => $self,
425 attributes => [ $self->get_all_attributes() ],
428 $self->add_meta_instance_dependencies()
429 if $instance->is_dependent_on_superclasses();
436 my $instance = shift;
437 (blessed($instance) && $instance->isa($class->name))
438 || confess "You must pass an instance of the metaclass (" . (ref $class ? $class->name : $class) . "), not ($instance)";
441 # we need to protect the integrity of the
442 # Class::MOP::Class singletons here, they
443 # should not be cloned.
444 return $instance if $instance->isa('Class::MOP::Class');
445 $class->_clone_instance($instance, @_);
449 Carp::cluck('The clone_instance method has been made private.'
450 . " The public version is deprecated and will be removed in a future release.\n");
451 shift->_clone_instance(@_);
454 sub _clone_instance {
455 my ($class, $instance, %params) = @_;
457 || confess "You can only clone instances, ($instance) is not a blessed instance";
458 my $meta_instance = $class->get_meta_instance();
459 my $clone = $meta_instance->clone_instance($instance);
460 foreach my $attr ($class->get_all_attributes()) {
461 if ( defined( my $init_arg = $attr->init_arg ) ) {
462 if (exists $params{$init_arg}) {
463 $attr->set_value($clone, $params{$init_arg});
470 sub rebless_instance {
471 my ($self, $instance, %params) = @_;
473 my $old_metaclass = Class::MOP::class_of($instance);
475 my $old_class = $old_metaclass ? $old_metaclass->name : blessed($instance);
476 $self->name->isa($old_class)
477 || confess "You may rebless only into a subclass of ($old_class), of which (". $self->name .") isn't.";
479 $old_metaclass->rebless_instance_away($instance, $self, %params)
482 my $meta_instance = $self->get_meta_instance();
485 # we use $_[1] here because of t/306_rebless_overload.t regressions on 5.8.8
486 $meta_instance->rebless_instance_structure($_[1], $self);
488 foreach my $attr ( $self->get_all_attributes ) {
489 if ( $attr->has_value($instance) ) {
490 if ( defined( my $init_arg = $attr->init_arg ) ) {
491 $params{$init_arg} = $attr->get_value($instance)
492 unless exists $params{$init_arg};
495 $attr->set_value($instance, $attr->get_value($instance));
500 foreach my $attr ($self->get_all_attributes) {
501 $attr->initialize_instance_slot($meta_instance, $instance, \%params);
507 sub rebless_instance_away {
508 # this intentionally does nothing, it is just a hook
515 my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA', create => 1 };
518 @{$self->get_package_symbol($var_spec)} = @supers;
521 # on 5.8 and below, we need to call
522 # a method to get Perl to detect
523 # a cycle in the class hierarchy
524 my $class = $self->name;
528 # we need to check the metaclass
529 # compatibility here so that we can
530 # be sure that the superclass is
531 # not potentially creating an issues
532 # we don't know about
534 $self->_check_metaclass_compatibility();
535 $self->_superclasses_updated();
537 @{$self->get_package_symbol($var_spec)};
540 sub _superclasses_updated {
542 $self->update_meta_instance_dependencies();
547 my $super_class = $self->name;
549 return @{ $super_class->mro::get_isarev() };
552 sub direct_subclasses {
554 my $super_class = $self->name;
559 } Class::MOP::Class->initialize($_)->superclasses
564 return @{ mro::get_linear_isa( (shift)->name ) };
567 sub class_precedence_list {
569 my $name = $self->name;
571 unless (Class::MOP::IS_RUNNING_ON_5_10()) {
573 # We need to check for circular inheritance here
574 # if we are are not on 5.10, cause 5.8 detects it
575 # late. This will do nothing if all is well, and
576 # blow up otherwise. Yes, it's an ugly hack, better
577 # suggestions are welcome.
579 ($name || return)->isa('This is a test for circular inheritance')
582 # if our mro is c3, we can
583 # just grab the linear_isa
584 if (mro::get_mro($name) eq 'c3') {
585 return @{ mro::get_linear_isa($name) }
589 # we can't grab the linear_isa for dfs
590 # since it has all the duplicates
595 $self->initialize($_)->class_precedence_list()
596 } $self->superclasses()
603 sub wrap_method_body {
604 my ( $self, %args ) = @_;
606 ('CODE' eq ref $args{body})
607 || confess "Your code block must be a CODE reference";
609 $self->method_metaclass->wrap(
610 package_name => $self->name,
616 my ($self, $method_name, $method) = @_;
617 (defined $method_name && $method_name)
618 || confess "You must define a method name";
621 if (blessed($method)) {
622 $body = $method->body;
623 if ($method->package_name ne $self->name) {
624 $method = $method->clone(
625 package_name => $self->name,
627 ) if $method->can('clone');
630 $method->attach_to_class($self);
631 $self->_method_map->{$method_name} = $method;
634 # If a raw code reference is supplied, its method object is not created.
635 # The method object won't be created until required.
640 my ( $current_package, $current_name ) = Class::MOP::get_code_info($body);
642 if ( !defined $current_name || $current_name eq '__ANON__' ) {
643 my $full_method_name = ($self->name . '::' . $method_name);
644 subname($full_method_name => $body);
647 $self->add_package_symbol(
648 { sigil => '&', type => 'CODE', name => $method_name },
654 my $fetch_and_prepare_method = sub {
655 my ($self, $method_name) = @_;
656 my $wrapped_metaclass = $self->wrapped_method_metaclass;
658 my $method = $self->get_method($method_name);
659 # if we dont have local ...
661 # try to find the next method
662 $method = $self->find_next_method_by_name($method_name);
663 # die if it does not exist
665 || confess "The method '$method_name' was not found in the inheritance hierarchy for " . $self->name;
666 # and now make sure to wrap it
667 # even if it is already wrapped
668 # because we need a new sub ref
669 $method = $wrapped_metaclass->wrap($method,
670 package_name => $self->name,
671 name => $method_name,
675 # now make sure we wrap it properly
676 $method = $wrapped_metaclass->wrap($method,
677 package_name => $self->name,
678 name => $method_name,
679 ) unless $method->isa($wrapped_metaclass);
681 $self->add_method($method_name => $method);
685 sub add_before_method_modifier {
686 my ($self, $method_name, $method_modifier) = @_;
687 (defined $method_name && $method_name)
688 || confess "You must pass in a method name";
689 my $method = $fetch_and_prepare_method->($self, $method_name);
690 $method->add_before_modifier(
691 subname(':before' => $method_modifier)
695 sub add_after_method_modifier {
696 my ($self, $method_name, $method_modifier) = @_;
697 (defined $method_name && $method_name)
698 || confess "You must pass in a method name";
699 my $method = $fetch_and_prepare_method->($self, $method_name);
700 $method->add_after_modifier(
701 subname(':after' => $method_modifier)
705 sub add_around_method_modifier {
706 my ($self, $method_name, $method_modifier) = @_;
707 (defined $method_name && $method_name)
708 || confess "You must pass in a method name";
709 my $method = $fetch_and_prepare_method->($self, $method_name);
710 $method->add_around_modifier(
711 subname(':around' => $method_modifier)
716 # the methods above used to be named like this:
717 # ${pkg}::${method}:(before|after|around)
718 # but this proved problematic when using one modifier
719 # to wrap multiple methods (something which is likely
720 # to happen pretty regularly IMO). So instead of naming
721 # it like this, I have chosen to just name them purely
722 # with their modifier names, like so:
723 # :(before|after|around)
724 # The fact is that in a stack trace, it will be fairly
725 # evident from the context what method they are attached
726 # to, and so don't need the fully qualified name.
730 Carp::cluck("The alias_method method is deprecated. Use add_method instead.\n");
732 shift->add_method(@_);
736 my ( $self, $code ) = @_;
738 my ( $code_package, $code_name ) = Class::MOP::get_code_info($code);
740 return $code_package && $code_package eq $self->name
741 || ( $code_package eq 'constant' && $code_name eq '__ANON__' );
745 my ($self, $method_name) = @_;
746 (defined $method_name && $method_name)
747 || confess "You must define a method name";
749 return defined($self->get_method($method_name));
753 my ($self, $method_name) = @_;
754 (defined $method_name && $method_name)
755 || confess "You must define a method name";
757 my $method_map = $self->_method_map;
758 my $method_object = $method_map->{$method_name};
759 my $code = $self->get_package_symbol({
760 name => $method_name,
765 unless ( $method_object && $method_object->body == ( $code || 0 ) ) {
766 if ( $code && $self->_code_is_mine($code) ) {
767 $method_object = $method_map->{$method_name}
768 = $self->wrap_method_body(
770 name => $method_name,
771 associated_metaclass => $self,
775 delete $method_map->{$method_name};
780 return $method_object;
784 my ($self, $method_name) = @_;
785 (defined $method_name && $method_name)
786 || confess "You must define a method name";
788 my $removed_method = delete $self->get_method_map->{$method_name};
790 $self->remove_package_symbol(
791 { sigil => '&', type => 'CODE', name => $method_name }
794 $removed_method->detach_from_class if $removed_method;
796 $self->update_package_cache_flag; # still valid, since we just removed the method from the map
798 return $removed_method;
801 sub get_method_list {
803 return grep { $self->has_method($_) } keys %{ $self->namespace };
806 sub find_method_by_name {
807 my ($self, $method_name) = @_;
808 (defined $method_name && $method_name)
809 || confess "You must define a method name to find";
810 foreach my $class ($self->linearized_isa) {
811 my $method = $self->initialize($class)->get_method($method_name);
812 return $method if defined $method;
817 sub get_all_methods {
819 my %methods = map { %{ $self->initialize($_)->get_method_map } } reverse $self->linearized_isa;
820 return values %methods;
823 sub compute_all_applicable_methods {
824 Carp::cluck('The compute_all_applicable_methods method is deprecated.'
825 . " Use get_all_methods instead.\n");
830 class => $_->package_name,
831 code => $_, # sigh, overloading
833 } shift->get_all_methods(@_);
836 sub get_all_method_names {
839 return grep { !$uniq{$_}++ } map { $self->initialize($_)->get_method_list } $self->linearized_isa;
842 sub find_all_methods_by_name {
843 my ($self, $method_name) = @_;
844 (defined $method_name && $method_name)
845 || confess "You must define a method name to find";
847 foreach my $class ($self->linearized_isa) {
848 # fetch the meta-class ...
849 my $meta = $self->initialize($class);
851 name => $method_name,
853 code => $meta->get_method($method_name)
854 } if $meta->has_method($method_name);
859 sub find_next_method_by_name {
860 my ($self, $method_name) = @_;
861 (defined $method_name && $method_name)
862 || confess "You must define a method name to find";
863 my @cpl = $self->linearized_isa;
864 shift @cpl; # discard ourselves
865 foreach my $class (@cpl) {
866 my $method = $self->initialize($class)->get_method($method_name);
867 return $method if defined $method;
876 # either we have an attribute object already
877 # or we need to create one from the args provided
878 my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_);
879 # make sure it is derived from the correct type though
880 ($attribute->isa('Class::MOP::Attribute'))
881 || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
883 # first we attach our new attribute
884 # because it might need certain information
885 # about the class which it is attached to
886 $attribute->attach_to_class($self);
888 my $attr_name = $attribute->name;
890 # then we remove attributes of a conflicting
891 # name here so that we can properly detach
892 # the old attr object, and remove any
893 # accessors it would have generated
894 if ( $self->has_attribute($attr_name) ) {
895 $self->remove_attribute($attr_name);
897 $self->invalidate_meta_instances();
900 # get our count of previously inserted attributes and
901 # increment by one so this attribute knows its order
902 my $order = (scalar keys %{$self->get_attribute_map});
903 $attribute->_set_insertion_order($order);
905 # then onto installing the new accessors
906 $self->get_attribute_map->{$attr_name} = $attribute;
908 # invalidate package flag here
912 eval { $attribute->install_accessors() };
916 $self->remove_attribute($attr_name);
923 sub update_meta_instance_dependencies {
926 if ( $self->{meta_instance_dependencies} ) {
927 return $self->add_meta_instance_dependencies;
931 sub add_meta_instance_dependencies {
934 $self->remove_meta_instance_dependencies;
936 my @attrs = $self->get_all_attributes();
939 my @classes = grep { not $seen{$_->name}++ } map { $_->associated_class } @attrs;
941 foreach my $class ( @classes ) {
942 $class->add_dependent_meta_instance($self);
945 $self->{meta_instance_dependencies} = \@classes;
948 sub remove_meta_instance_dependencies {
951 if ( my $classes = delete $self->{meta_instance_dependencies} ) {
952 foreach my $class ( @$classes ) {
953 $class->remove_dependent_meta_instance($self);
963 sub add_dependent_meta_instance {
964 my ( $self, $metaclass ) = @_;
965 push @{ $self->{dependent_meta_instances} }, $metaclass;
968 sub remove_dependent_meta_instance {
969 my ( $self, $metaclass ) = @_;
970 my $name = $metaclass->name;
971 @$_ = grep { $_->name ne $name } @$_ for $self->{dependent_meta_instances};
974 sub invalidate_meta_instances {
976 $_->invalidate_meta_instance() for $self, @{ $self->{dependent_meta_instances} };
979 sub invalidate_meta_instance {
981 undef $self->{_meta_instance};
985 my ($self, $attribute_name) = @_;
986 (defined $attribute_name && $attribute_name)
987 || confess "You must define an attribute name";
988 exists $self->get_attribute_map->{$attribute_name};
992 my ($self, $attribute_name) = @_;
993 (defined $attribute_name && $attribute_name)
994 || confess "You must define an attribute name";
995 return $self->get_attribute_map->{$attribute_name}
997 # this will return undef anyway, so no need ...
998 # if $self->has_attribute($attribute_name);
1002 sub remove_attribute {
1003 my ($self, $attribute_name) = @_;
1004 (defined $attribute_name && $attribute_name)
1005 || confess "You must define an attribute name";
1006 my $removed_attribute = $self->get_attribute_map->{$attribute_name};
1007 return unless defined $removed_attribute;
1008 delete $self->get_attribute_map->{$attribute_name};
1009 $self->invalidate_meta_instances();
1010 $removed_attribute->remove_accessors();
1011 $removed_attribute->detach_from_class();
1012 return $removed_attribute;
1015 sub get_attribute_list {
1017 keys %{$self->get_attribute_map};
1020 sub get_all_attributes {
1022 my %attrs = map { %{ $self->initialize($_)->get_attribute_map } } reverse $self->linearized_isa;
1023 return values %attrs;
1026 sub compute_all_applicable_attributes {
1027 Carp::cluck('The compute_all_applicable_attributes method has been deprecated.'
1028 . " Use get_all_attributes instead.\n");
1030 shift->get_all_attributes(@_);
1033 sub find_attribute_by_name {
1034 my ($self, $attr_name) = @_;
1035 foreach my $class ($self->linearized_isa) {
1036 # fetch the meta-class ...
1037 my $meta = $self->initialize($class);
1038 return $meta->get_attribute($attr_name)
1039 if $meta->has_attribute($attr_name);
1044 # check if we can reinitialize
1048 # if any local attr is defined
1049 return if $self->get_attribute_list;
1051 # or any non-declared methods
1052 if ( my @methods = values %{ $self->get_method_map } ) {
1053 my $metaclass = $self->method_metaclass;
1054 foreach my $method ( @methods ) {
1055 return if $method->isa("Class::MOP::Method::Generated");
1056 # FIXME do we need to enforce this too? return unless $method->isa($metaclass);
1065 sub is_mutable { 1 }
1066 sub is_immutable { 0 }
1068 sub _immutable_options {
1069 my ( $self, @args ) = @_;
1072 inline_accessors => 1,
1073 inline_constructor => 1,
1074 inline_destructor => 0,
1076 immutable_trait => $self->immutable_trait,
1077 constructor_name => $self->constructor_name,
1078 constructor_class => $self->constructor_class,
1079 destructor_class => $self->destructor_class,
1084 sub make_immutable {
1085 my ( $self, @args ) = @_;
1087 if ( $self->is_mutable ) {
1088 $self->_initialize_immutable( $self->_immutable_options(@args) );
1089 $self->_rebless_as_immutable(@args);
1100 if ( $self->is_immutable ) {
1101 my @args = $self->immutable_options;
1102 $self->_rebless_as_mutable();
1103 $self->_remove_inlined_code(@args);
1104 delete $self->{__immutable};
1112 sub _rebless_as_immutable {
1113 my ( $self, @args ) = @_;
1115 $self->{__immutable}{original_class} = ref $self;
1117 bless $self => $self->_immutable_metaclass(@args);
1120 sub _immutable_metaclass {
1121 my ( $self, %args ) = @_;
1123 if ( my $class = $args{immutable_metaclass} ) {
1127 my $trait = $args{immutable_trait} = $self->immutable_trait
1128 || confess "no immutable trait specified for $self";
1130 my $meta = $self->meta;
1131 my $meta_attr = $meta->find_attribute_by_name("immutable_trait");
1135 if ( $meta_attr and $trait eq $meta_attr->default ) {
1136 # if the trait is the same as the default we try and pick a
1137 # predictable name for the immutable metaclass
1138 $class_name = 'Class::MOP::Class::Immutable::' . ref($self);
1141 $class_name = join '::', 'Class::MOP::Class::Immutable::CustomTrait',
1142 $trait, 'ForMetaClass', ref($self);
1146 if Class::MOP::is_class_loaded($class_name);
1148 # If the metaclass is a subclass of CMOP::Class which has had
1149 # metaclass roles applied (via Moose), then we want to make sure
1150 # that we preserve that anonymous class (see Fey::ORM for an
1151 # example of where this matters).
1153 = $meta->is_immutable
1154 ? $meta->get_mutable_metaclass_name
1157 my $immutable_meta = $meta_name->create(
1159 superclasses => [ ref $self ],
1162 Class::MOP::load_class($trait);
1163 for my $meth ( Class::MOP::Class->initialize($trait)->get_all_methods ) {
1164 my $meth_name = $meth->name;
1166 if ( $immutable_meta->find_method_by_name( $meth_name ) ) {
1167 $immutable_meta->add_around_method_modifier( $meth_name, $meth->body );
1170 $immutable_meta->add_method( $meth_name, $meth->clone );
1174 $immutable_meta->make_immutable(
1175 inline_constructor => 0,
1176 inline_accessors => 0,
1182 sub _remove_inlined_code {
1185 $self->remove_method( $_->name ) for $self->_inlined_methods;
1187 delete $self->{__immutable}{inlined_methods};
1190 sub _inlined_methods { @{ $_[0]{__immutable}{inlined_methods} || [] } }
1192 sub _add_inlined_method {
1193 my ( $self, $method ) = @_;
1195 push @{ $self->{__immutable}{inlined_methods} ||= [] }, $method;
1198 sub _initialize_immutable {
1199 my ( $self, %args ) = @_;
1201 $self->{__immutable}{options} = \%args;
1202 $self->_install_inlined_code(%args);
1205 sub _install_inlined_code {
1206 my ( $self, %args ) = @_;
1209 $self->_inline_accessors(%args) if $args{inline_accessors};
1210 $self->_inline_constructor(%args) if $args{inline_constructor};
1211 $self->_inline_destructor(%args) if $args{inline_destructor};
1214 sub _rebless_as_mutable {
1217 bless $self, $self->get_mutable_metaclass_name;
1222 sub _inline_accessors {
1225 foreach my $attr_name ( $self->get_attribute_list ) {
1226 $self->get_attribute($attr_name)->install_accessors(1);
1230 sub _inline_constructor {
1231 my ( $self, %args ) = @_;
1233 my $name = $args{constructor_name};
1235 if ( $self->has_method($name) && !$args{replace_constructor} ) {
1236 my $class = $self->name;
1237 warn "Not inlining a constructor for $class since it defines"
1238 . " its own constructor.\n"
1239 . "If you are certain you don't need to inline your"
1240 . " constructor, specify inline_constructor => 0 in your"
1241 . " call to $class->meta->make_immutable\n";
1245 my $constructor_class = $args{constructor_class};
1247 Class::MOP::load_class($constructor_class);
1249 my $constructor = $constructor_class->new(
1253 package_name => $self->name,
1257 if ( $args{replace_constructor} or $constructor->can_be_inlined ) {
1258 $self->add_method( $name => $constructor );
1259 $self->_add_inlined_method($constructor);
1263 sub _inline_destructor {
1264 my ( $self, %args ) = @_;
1266 ( exists $args{destructor_class} && defined $args{destructor_class} )
1267 || confess "The 'inline_destructor' option is present, but "
1268 . "no destructor class was specified";
1270 if ( $self->has_method('DESTROY') && ! $args{replace_destructor} ) {
1271 my $class = $self->name;
1272 warn "Not inlining a destructor for $class since it defines"
1273 . " its own destructor.\n";
1277 my $destructor_class = $args{destructor_class};
1279 Class::MOP::load_class($destructor_class);
1281 return unless $destructor_class->is_needed($self);
1283 my $destructor = $destructor_class->new(
1286 package_name => $self->name,
1290 if ( $args{replace_destructor} or $destructor->can_be_inlined ) {
1291 $self->add_method( 'DESTROY' => $destructor );
1292 $self->_add_inlined_method($destructor);
1304 Class::MOP::Class - Class Meta Object
1308 # assuming that class Foo
1309 # has been defined, you can
1311 # use this for introspection ...
1313 # add a method to Foo ...
1314 Foo->meta->add_method( 'bar' => sub {...} )
1316 # get a list of all the classes searched
1317 # the method dispatcher in the correct order
1318 Foo->meta->class_precedence_list()
1320 # remove a method from Foo
1321 Foo->meta->remove_method('bar');
1323 # or use this to actually create classes ...
1325 Class::MOP::Class->create(
1328 superclasses => ['Foo'],
1330 Class::MOP::Attribute->new('$bar'),
1331 Class::MOP::Attribute->new('$baz'),
1334 calculate_bar => sub {...},
1335 construct_baz => sub {...}
1342 The Class Protocol is the largest and most complex part of the
1343 Class::MOP meta-object protocol. It controls the introspection and
1344 manipulation of Perl 5 classes, and it can create them as well. The
1345 best way to understand what this module can do, is to read the
1346 documentation for each of its methods.
1350 C<Class::MOP::Class> is a subclass of L<Class::MOP::Module>.
1354 =head2 Class construction
1356 These methods all create new C<Class::MOP::Class> objects. These
1357 objects can represent existing classes, or they can be used to create
1358 new classes from scratch.
1360 The metaclass object for a given class is a singleton. If you attempt
1361 to create a metaclass for the same class twice, you will just get the
1366 =item B<< Class::MOP::Class->create($package_name, %options) >>
1368 This method creates a new C<Class::MOP::Class> object with the given
1369 package name. It accepts a number of options.
1375 An optional version number for the newly created package.
1379 An optional authority for the newly created package.
1381 =item * superclasses
1383 An optional array reference of superclass names.
1387 An optional hash reference of methods for the class. The keys of the
1388 hash reference are method names, and values are subroutine references.
1392 An optional array reference of L<Class::MOP::Attribute> objects.
1396 =item B<< Class::MOP::Class->create_anon_class(%options) >>
1398 This method works just like C<< Class::MOP::Class->create >> but it
1399 creates an "anonymous" class. In fact, the class does have a name, but
1400 that name is a unique name generated internally by this module.
1402 It accepts the same C<superclasses>, C<methods>, and C<attributes>
1403 parameters that C<create> accepts.
1405 Anonymous classes are destroyed once the metaclass they are attached
1406 to goes out of scope, and will be removed from Perl's internal symbol
1409 All instances of an anonymous class keep a special reference to the
1410 metaclass object, which prevents the metaclass from going out of scope
1411 while any instances exist.
1413 This only works if the instance if based on a hash reference, however.
1415 =item B<< Class::MOP::Class->initialize($package_name, %options) >>
1417 This method will initialize a C<Class::MOP::Class> object for the
1418 named package. Unlike C<create>, this method I<will not> create a new
1421 The purpose of this method is to retrieve a C<Class::MOP::Class>
1422 object for introspecting an existing class.
1424 If an existing C<Class::MOP::Class> object exists for the named
1425 package, it will be returned, and any options provided will be
1428 If the object does not yet exist, it will be created.
1430 The valid options that can be passed to this method are
1431 C<attribute_metaclass>, C<method_metaclass>,
1432 C<wrapped_method_metaclass>, and C<instance_metaclass>. These are all
1433 optional, and default to the appropriate class in the C<Class::MOP>
1438 =head2 Object instance construction and cloning
1440 These methods are all related to creating and/or cloning object
1445 =item B<< $metaclass->clone_object($instance, %params) >>
1447 This method clones an existing object instance. Any parameters you
1448 provide are will override existing attribute values in the object.
1450 This is a convenience method for cloning an object instance, then
1451 blessing it into the appropriate package.
1453 You could implement a clone method in your class, using this method:
1456 my ($self, %params) = @_;
1457 $self->meta->clone_object($self, %params);
1460 =item B<< $metaclass->rebless_instance($instance, %params) >>
1462 This method changes the class of C<$instance> to the metaclass's class.
1464 You can only rebless an instance into a subclass of its current
1465 class. If you pass any additional parameters, these will be treated
1466 like constructor parameters and used to initialize the object's
1467 attributes. Any existing attributes that are already set will be
1470 Before reblessing the instance, this method will call
1471 C<rebless_instance_away> on the instance's current metaclass. This method
1472 will be passed the instance, the new metaclass, and any parameters
1473 specified to C<rebless_instance>. By default, C<rebless_instance_away>
1474 does nothing; it is merely a hook.
1476 =item B<< $metaclass->new_object(%params) >>
1478 This method is used to create a new object of the metaclass's
1479 class. Any parameters you provide are used to initialize the
1480 instance's attributes. A special C<__INSTANCE__> key can be passed to
1481 provide an already generated instance, rather than having Class::MOP
1482 generate it for you. This is mostly useful for using Class::MOP with
1483 foreign classes, which generally generate instances using their own
1486 =item B<< $metaclass->instance_metaclass >>
1488 Returns the class name of the instance metaclass, see
1489 L<Class::MOP::Instance> for more information on the instance
1492 =item B<< $metaclass->get_meta_instance >>
1494 Returns an instance of the C<instance_metaclass> to be used in the
1495 construction of a new instance of the class.
1499 =head2 Informational predicates
1501 These are a few predicate methods for asking information about the
1506 =item B<< $metaclass->is_anon_class >>
1508 This returns true if the class was created by calling C<<
1509 Class::MOP::Class->create_anon_class >>.
1511 =item B<< $metaclass->is_mutable >>
1513 This returns true if the class is still mutable.
1515 =item B<< $metaclass->is_immutable >>
1517 This returns true if the class has been made immutable.
1519 =item B<< $metaclass->is_pristine >>
1521 A class is I<not> pristine if it has non-inherited attributes or if it
1522 has any generated methods.
1526 =head2 Inheritance Relationships
1530 =item B<< $metaclass->superclasses(@superclasses) >>
1532 This is a read-write accessor which represents the superclass
1533 relationships of the metaclass's class.
1535 This is basically sugar around getting and setting C<@ISA>.
1537 =item B<< $metaclass->class_precedence_list >>
1539 This returns a list of all of the class's ancestor classes. The
1540 classes are returned in method dispatch order.
1542 =item B<< $metaclass->linearized_isa >>
1544 This returns a list based on C<class_precedence_list> but with all
1547 =item B<< $metaclass->subclasses >>
1549 This returns a list of all subclasses for this class, even indirect
1552 =item B<< $metaclass->direct_subclasses >>
1554 This returns a list of immediate subclasses for this class, which does not
1555 include indirect subclasses.
1559 =head2 Method introspection and creation
1561 These methods allow you to introspect a class's methods, as well as
1562 add, remove, or change methods.
1564 Determining what is truly a method in a Perl 5 class requires some
1565 heuristics (aka guessing).
1567 Methods defined outside the package with a fully qualified name (C<sub
1568 Package::name { ... }>) will be included. Similarly, methods named
1569 with a fully qualified name using L<Sub::Name> are also included.
1571 However, we attempt to ignore imported functions.
1573 Ultimately, we are using heuristics to determine what truly is a
1574 method in a class, and these heuristics may get the wrong answer in
1575 some edge cases. However, for most "normal" cases the heuristics work
1580 =item B<< $metaclass->get_method($method_name) >>
1582 This will return a L<Class::MOP::Method> for the specified
1583 C<$method_name>. If the class does not have the specified method, it
1586 =item B<< $metaclass->has_method($method_name) >>
1588 Returns a boolean indicating whether or not the class defines the
1589 named method. It does not include methods inherited from parent
1592 =item B<< $metaclass->get_method_map >>
1594 Returns a hash reference representing the methods defined in this
1595 class. The keys are method names and the values are
1596 L<Class::MOP::Method> objects.
1598 =item B<< $metaclass->get_method_list >>
1600 This will return a list of method I<names> for all methods defined in
1603 =item B<< $metaclass->get_all_methods >>
1605 This will traverse the inheritance hierarchy and return a list of all
1606 the L<Class::MOP::Method> objects for this class and its parents.
1608 =item B<< $metaclass->find_method_by_name($method_name) >>
1610 This will return a L<Class::MOP::Method> for the specified
1611 C<$method_name>. If the class does not have the specified method, it
1614 Unlike C<get_method>, this method I<will> look for the named method in
1617 =item B<< $metaclass->get_all_method_names >>
1619 This will return a list of method I<names> for all of this class's
1620 methods, including inherited methods.
1622 =item B<< $metaclass->find_all_methods_by_name($method_name) >>
1624 This method looks for the named method in the class and all of its
1625 parents. It returns every matching method it finds in the inheritance
1626 tree, so it returns a list of methods.
1628 Each method is returned as a hash reference with three keys. The keys
1629 are C<name>, C<class>, and C<code>. The C<code> key has a
1630 L<Class::MOP::Method> object as its value.
1632 The list of methods is distinct.
1634 =item B<< $metaclass->find_next_method_by_name($method_name) >>
1636 This method returns the first method in any superclass matching the
1637 given name. It is effectively the method that C<SUPER::$method_name>
1640 =item B<< $metaclass->add_method($method_name, $method) >>
1642 This method takes a method name and a subroutine reference, and adds
1643 the method to the class.
1645 The subroutine reference can be a L<Class::MOP::Method>, and you are
1646 strongly encouraged to pass a meta method object instead of a code
1647 reference. If you do so, that object gets stored as part of the
1648 class's method map directly. If not, the meta information will have to
1649 be recreated later, and may be incorrect.
1651 If you provide a method object, this method will clone that object if
1652 the object's package name does not match the class name. This lets us
1653 track the original source of any methods added from other classes
1654 (notably Moose roles).
1656 =item B<< $metaclass->remove_method($method_name) >>
1658 Remove the named method from the class. This method returns the
1659 L<Class::MOP::Method> object for the method.
1661 =item B<< $metaclass->method_metaclass >>
1663 Returns the class name of the method metaclass, see
1664 L<Class::MOP::Method> for more information on the method metaclass.
1666 =item B<< $metaclass->wrapped_method_metaclass >>
1668 Returns the class name of the wrapped method metaclass, see
1669 L<Class::MOP::Method::Wrapped> for more information on the wrapped
1674 =head2 Attribute introspection and creation
1676 Because Perl 5 does not have a core concept of attributes in classes,
1677 we can only return information about attributes which have been added
1678 via this class's methods. We cannot discover information about
1679 attributes which are defined in terms of "regular" Perl 5 methods.
1683 =item B<< $metaclass->get_attribute($attribute_name) >>
1685 This will return a L<Class::MOP::Attribute> for the specified
1686 C<$attribute_name>. If the class does not have the specified
1687 attribute, it returns C<undef>.
1689 NOTE that get_attribute does not search superclasses, for that you
1690 need to use C<find_attribute_by_name>.
1692 =item B<< $metaclass->has_attribute($attribute_name) >>
1694 Returns a boolean indicating whether or not the class defines the
1695 named attribute. It does not include attributes inherited from parent
1698 =item B<< $metaclass->get_attribute_map >>
1700 Returns a hash reference representing the attributes defined in this
1701 class. The keys are attribute names and the values are
1702 L<Class::MOP::Attribute> objects.
1704 =item B<< $metaclass->get_attribute_list >>
1706 This will return a list of attributes I<names> for all attributes
1707 defined in this class.
1709 =item B<< $metaclass->get_all_attributes >>
1711 This will traverse the inheritance hierarchy and return a list of all
1712 the L<Class::MOP::Attribute> objects for this class and its parents.
1714 =item B<< $metaclass->find_attribute_by_name($attribute_name) >>
1716 This will return a L<Class::MOP::Attribute> for the specified
1717 C<$attribute_name>. If the class does not have the specified
1718 attribute, it returns C<undef>
1720 Unlike C<get_attribute>, this attribute I<will> look for the named
1721 attribute in superclasses.
1723 =item B<< $metaclass->add_attribute(...) >>
1725 This method accepts either an existing L<Class::MOP::Attribute>
1726 object, or parameters suitable for passing to that class's C<new>
1729 The attribute provided will be added to the class.
1731 Any accessor methods defined by the attribute will be added to the
1732 class when the attribute is added.
1734 If an attribute of the same name already exists, the old attribute
1735 will be removed first.
1737 =item B<< $metaclass->remove_attribute($attribute_name) >>
1739 This will remove the named attribute from the class, and
1740 L<Class::MOP::Attribute> object.
1742 Removing an attribute also removes any accessor methods defined by the
1745 However, note that removing an attribute will only affect I<future>
1746 object instances created for this class, not existing instances.
1748 =item B<< $metaclass->attribute_metaclass >>
1750 Returns the class name of the attribute metaclass for this class. By
1751 default, this is L<Class::MOP::Attribute>. for more information on
1755 =head2 Class Immutability
1757 Making a class immutable "freezes" the class definition. You can no
1758 longer call methods which alter the class, such as adding or removing
1759 methods or attributes.
1761 Making a class immutable lets us optimize the class by inlining some
1762 methods, and also allows us to optimize some methods on the metaclass
1765 After immutabilization, the metaclass object will cache most
1766 informational methods such as C<get_method_map> and
1767 C<get_all_attributes>. Methods which would alter the class, such as
1768 C<add_attribute>, C<add_method>, and so on will throw an error on an
1769 immutable metaclass object.
1771 The immutabilization system in L<Moose> takes much greater advantage
1772 of the inlining features than Class::MOP itself does.
1776 =item B<< $metaclass->make_immutable(%options) >>
1778 This method will create an immutable transformer and uses it to make
1779 the class and its metaclass object immutable.
1781 This method accepts the following options:
1785 =item * inline_accessors
1787 =item * inline_constructor
1789 =item * inline_destructor
1791 These are all booleans indicating whether the specified method(s)
1794 By default, accessors and the constructor are inlined, but not the
1797 =item * immutable_trait
1799 The name of a class which will be used as a parent class for the
1800 metaclass object being made immutable. This "trait" implements the
1801 post-immutability functionality of the metaclass (but not the
1802 transformation itself).
1804 This defaults to L<Class::MOP::Class::Immutable::Trait>.
1806 =item * constructor_name
1808 This is the constructor method name. This defaults to "new".
1810 =item * constructor_class
1812 The name of the method metaclass for constructors. It will be used to
1813 generate the inlined constructor. This defaults to
1814 "Class::MOP::Method::Constructor".
1816 =item * replace_constructor
1818 This is a boolean indicating whether an existing constructor should be
1819 replaced when inlining a constructor. This defaults to false.
1821 =item * destructor_class
1823 The name of the method metaclass for destructors. It will be used to
1824 generate the inlined destructor. This defaults to
1825 "Class::MOP::Method::Denstructor".
1827 =item * replace_destructor
1829 This is a boolean indicating whether an existing destructor should be
1830 replaced when inlining a destructor. This defaults to false.
1834 =item B<< $metaclass->make_mutable >>
1836 Calling this method reverse the immutabilization transformation.
1840 =head2 Method Modifiers
1842 Method modifiers are hooks which allow a method to be wrapped with
1843 I<before>, I<after> and I<around> method modifiers. Every time a
1844 method is called, it's modifiers are also called.
1846 A class can modify its own methods, as well as methods defined in
1849 =head3 How method modifiers work?
1851 Method modifiers work by wrapping the original method and then
1852 replacing it in the class's symbol table. The wrappers will handle
1853 calling all the modifiers in the appropriate order and preserving the
1854 calling context for the original method.
1856 The return values of C<before> and C<after> modifiers are
1857 ignored. This is because their purpose is B<not> to filter the input
1858 and output of the primary method (this is done with an I<around>
1861 This may seem like an odd restriction to some, but doing this allows
1862 for simple code to be added at the beginning or end of a method call
1863 without altering the function of the wrapped method or placing any
1864 extra responsibility on the code of the modifier.
1866 Of course if you have more complex needs, you can use the C<around>
1867 modifier which allows you to change both the parameters passed to the
1868 wrapped method, as well as its return value.
1870 Before and around modifiers are called in last-defined-first-called
1871 order, while after modifiers are called in first-defined-first-called
1872 order. So the call tree might looks something like this:
1884 =head3 What is the performance impact?
1886 Of course there is a performance cost associated with method
1887 modifiers, but we have made every effort to make that cost directly
1888 proportional to the number of modifier features you utilize.
1890 The wrapping method does it's best to B<only> do as much work as it
1891 absolutely needs to. In order to do this we have moved some of the
1892 performance costs to set-up time, where they are easier to amortize.
1894 All this said, our benchmarks have indicated the following:
1896 simple wrapper with no modifiers 100% slower
1897 simple wrapper with simple before modifier 400% slower
1898 simple wrapper with simple after modifier 450% slower
1899 simple wrapper with simple around modifier 500-550% slower
1900 simple wrapper with all 3 modifiers 1100% slower
1902 These numbers may seem daunting, but you must remember, every feature
1903 comes with some cost. To put things in perspective, just doing a
1904 simple C<AUTOLOAD> which does nothing but extract the name of the
1905 method called and return it costs about 400% over a normal method
1910 =item B<< $metaclass->add_before_method_modifier($method_name, $code) >>
1912 This wraps the specified method with the supplied subroutine
1913 reference. The modifier will be called as a method itself, and will
1914 receive the same arguments as are passed to the method.
1916 When the modifier exits, the wrapped method will be called.
1918 The return value of the modifier will be ignored.
1920 =item B<< $metaclass->add_after_method_modifier($method_name, $code) >>
1922 This wraps the specified method with the supplied subroutine
1923 reference. The modifier will be called as a method itself, and will
1924 receive the same arguments as are passed to the method.
1926 When the wrapped methods exits, the modifier will be called.
1928 The return value of the modifier will be ignored.
1930 =item B<< $metaclass->add_around_method_modifier($method_name, $code) >>
1932 This wraps the specified method with the supplied subroutine
1935 The first argument passed to the modifier will be a subroutine
1936 reference to the wrapped method. The second argument is the object,
1937 and after that come any arguments passed when the method is called.
1939 The around modifier can choose to call the original method, as well as
1940 what arguments to pass if it does so.
1942 The return value of the modifier is what will be seen by the caller.
1946 =head2 Introspection
1950 =item B<< Class::MOP::Class->meta >>
1952 This will return a L<Class::MOP::Class> instance for this class.
1954 It should also be noted that L<Class::MOP> will actually bootstrap
1955 this module by installing a number of attribute meta-objects into its
1962 Stevan Little E<lt>stevan@iinteractive.comE<gt>
1964 =head1 COPYRIGHT AND LICENSE
1966 Copyright 2006-2009 by Infinity Interactive, Inc.
1968 L<http://www.iinteractive.com>
1970 This library is free software; you can redistribute it and/or modify
1971 it under the same terms as Perl itself.