use warnings;
use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype';
+use Scalar::Util 'blessed', 'reftype', 'weaken';
use Sub::Name 'subname';
use B 'svref_2object';
-use Clone ();
-our $VERSION = '0.03';
+our $VERSION = '0.19';
+our $AUTHORITY = 'cpan:STEVAN';
-# Self-introspection
+use base 'Class::MOP::Module';
-sub meta { Class::MOP::Class->initialize($_[0]) }
+use Class::MOP::Instance;
+
+# Self-introspection
+
+sub meta { Class::MOP::Class->initialize(blessed($_[0]) || $_[0]) }
# Creation
+
+sub initialize {
+ my $class = shift;
+ my $package_name = shift;
+ (defined $package_name && $package_name && !blessed($package_name))
+ || confess "You must pass a package name and it cannot be blessed";
+ $class->construct_class_instance(':package' => $package_name, @_);
+}
-{
- # Metaclasses are singletons, so we cache them here.
- # there is no need to worry about destruction though
- # because they should die only when the program dies.
- # After all, do package definitions even get reaped?
- my %METAS;
+sub reinitialize {
+ my $class = shift;
+ my $package_name = shift;
+ (defined $package_name && $package_name && !blessed($package_name))
+ || confess "You must pass a package name and it cannot be blessed";
+ Class::MOP::remove_metaclass_by_name($package_name);
+ $class->construct_class_instance(':package' => $package_name, @_);
+}
- sub initialize {
- my $class = shift;
- my $package_name = shift;
- (defined $package_name && $package_name)
- || confess "You must pass a package name";
- # make sure the package name is not blessed
- $package_name = blessed($package_name) || $package_name;
- $class->construct_class_instance(':package' => $package_name, @_);
+# NOTE: (meta-circularity)
+# this is a special form of &construct_instance
+# (see below), which is used to construct class
+# meta-object instances for any Class::MOP::*
+# class. All other classes will use the more
+# normal &construct_instance.
+sub construct_class_instance {
+ my $class = shift;
+ my %options = @_;
+ my $package_name = $options{':package'};
+ (defined $package_name && $package_name)
+ || confess "You must pass a package name";
+ # NOTE:
+ # return the metaclass if we have it cached,
+ # and it is still defined (it has not been
+ # reaped by DESTROY yet, which can happen
+ # annoyingly enough during global destruction)
+ return Class::MOP::get_metaclass_by_name($package_name)
+ if Class::MOP::does_metaclass_exist($package_name);
+
+ # NOTE:
+ # we need to deal with the possibility
+ # of class immutability here, and then
+ # get the name of the class appropriately
+ $class = (blessed($class)
+ ? ($class->is_immutable
+ ? $class->get_mutable_metaclass_name()
+ : blessed($class))
+ : $class);
+
+ $class = blessed($class) || $class;
+ # now create the metaclass
+ my $meta;
+ if ($class =~ /^Class::MOP::Class$/) {
+ no strict 'refs';
+ $meta = bless {
+ # inherited from Class::MOP::Package
+ '$:package' => $package_name,
+
+ # NOTE:
+ # since the following attributes will
+ # actually be loaded from the symbol
+ # table, and actually bypass the instance
+ # entirely, we can just leave these things
+ # listed here for reference, because they
+ # should not actually have a value associated
+ # with the slot.
+ '%:namespace' => \undef,
+ # inherited from Class::MOP::Module
+ '$:version' => \undef,
+ '$:authority' => \undef,
+ # defined in Class::MOP::Class
+
+ '%:methods' => {},
+ '%:attributes' => {},
+ '$:attribute_metaclass' => $options{':attribute_metaclass'} || 'Class::MOP::Attribute',
+ '$:method_metaclass' => $options{':method_metaclass'} || 'Class::MOP::Method',
+ '$:instance_metaclass' => $options{':instance_metaclass'} || 'Class::MOP::Instance',
+ } => $class;
+ }
+ else {
+ # NOTE:
+ # it is safe to use meta here because
+ # class will always be a subclass of
+ # Class::MOP::Class, which defines meta
+ $meta = $class->meta->construct_instance(%options)
}
- # NOTE: (meta-circularity)
- # this is a special form of &construct_instance
- # (see below), which is used to construct class
- # meta-object instances for any Class::MOP::*
- # class. All other classes will use the more
- # normal &construct_instance.
- sub construct_class_instance {
- my $class = shift;
- my %options = @_;
- my $package_name = $options{':package'};
- (defined $package_name && $package_name)
- || confess "You must pass a package name";
- return $METAS{$package_name} if exists $METAS{$package_name};
- $class = blessed($class) || $class;
- if ($class =~ /^Class::MOP::/) {
- $METAS{$package_name} = bless {
- '$:package' => $package_name,
- '%:attributes' => {},
- '$:attribute_metaclass' => 'Class::MOP::Attribute',
- '$:method_metaclass' => 'Class::MOP::Method',
- } => $class;
- }
- else {
- # NOTE:
- # it is safe to use meta here because
- # class will always be a subclass of
- # Class::MOP::Class, which defines meta
- $METAS{$package_name} = bless $class->meta->construct_instance(%options) => $class
+ # and check the metaclass compatibility
+ $meta->check_metaclass_compatability();
+
+ Class::MOP::store_metaclass_by_name($package_name, $meta);
+
+ # NOTE:
+ # we need to weaken any anon classes
+ # so that they can call DESTROY properly
+ Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class;
+
+ $meta;
+}
+
+sub check_metaclass_compatability {
+ my $self = shift;
+
+ # this is always okay ...
+ return if blessed($self) eq 'Class::MOP::Class' &&
+ $self->instance_metaclass eq 'Class::MOP::Instance';
+
+ my @class_list = $self->class_precedence_list;
+ shift @class_list; # shift off $self->name
+
+ foreach my $class_name (@class_list) {
+ my $meta = Class::MOP::get_metaclass_by_name($class_name) || next;
+
+ # NOTE:
+ # we need to deal with the possibility
+ # of class immutability here, and then
+ # get the name of the class appropriately
+ my $meta_type = ($meta->is_immutable
+ ? $meta->get_mutable_metaclass_name()
+ : blessed($meta));
+
+ ($self->isa($meta_type))
+ || confess $self->name . "->meta => (" . (blessed($self)) . ")" .
+ " is not compatible with the " .
+ $class_name . "->meta => (" . ($meta_type) . ")";
+ # NOTE:
+ # we also need to check that instance metaclasses
+ # are compatabile in the same the class.
+ ($self->instance_metaclass->isa($meta->instance_metaclass))
+ || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" .
+ " is not compatible with the " .
+ $class_name . "->meta => (" . ($meta->instance_metaclass) . ")";
+ }
+}
+
+## ANON classes
+
+{
+ # NOTE:
+ # this should be sufficient, if you have a
+ # use case where it is not, write a test and
+ # I will change it.
+ my $ANON_CLASS_SERIAL = 0;
+
+ # NOTE:
+ # we need a sufficiently annoying prefix
+ # this should suffice for now, this is
+ # used in a couple of places below, so
+ # need to put it up here for now.
+ my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::';
+
+ sub is_anon_class {
+ my $self = shift;
+ $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0;
+ }
+
+ sub create_anon_class {
+ my ($class, %options) = @_;
+ my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL;
+ return $class->create($package_name, %options);
+ }
+
+ # NOTE:
+ # this will only get called for
+ # anon-classes, all other calls
+ # are assumed to occur during
+ # global destruction and so don't
+ # really need to be handled explicitly
+ sub DESTROY {
+ my $self = shift;
+ return unless $self->name =~ /^$ANON_CLASS_PREFIX/;
+ my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/);
+ no strict 'refs';
+ foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) {
+ delete ${$ANON_CLASS_PREFIX . $serial_id}{$key};
}
+ delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'};
}
+
}
+# creating classes with MOP ...
+
sub create {
- my ($class, $package_name, $package_version, %options) = @_;
+ my $class = shift;
+ my $package_name = shift;
+
(defined $package_name && $package_name)
|| confess "You must pass a package name";
+
+ (scalar @_ % 2 == 0)
+ || confess "You much pass all parameters as name => value pairs " .
+ "(I found an uneven number of params in \@_)";
+
+ my (%options) = @_;
+
my $code = "package $package_name;";
- $code .= "\$$package_name\:\:VERSION = '$package_version';"
- if defined $package_version;
+ $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';"
+ if exists $options{version};
+ $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';"
+ if exists $options{authority};
+
eval $code;
confess "creation of $package_name failed : $@" if $@;
+
my $meta = $class->initialize($package_name);
+
+ $meta->add_method('meta' => sub {
+ $class->initialize(blessed($_[0]) || $_[0]);
+ });
+
$meta->superclasses(@{$options{superclasses}})
if exists $options{superclasses};
# NOTE:
# all these attribute readers will be bootstrapped
# away in the Class::MOP bootstrap section
-sub name { $_[0]->{'$:package'} }
sub get_attribute_map { $_[0]->{'%:attributes'} }
sub attribute_metaclass { $_[0]->{'$:attribute_metaclass'} }
sub method_metaclass { $_[0]->{'$:method_metaclass'} }
+sub instance_metaclass { $_[0]->{'$:instance_metaclass'} }
+
+sub get_method_map {
+ my $self = shift;
+ my $map = $self->{'%:methods'};
+
+ foreach my $symbol (grep { $self->has_package_symbol('&' . $_) } $self->list_all_package_symbols) {
+ next if exists $map->{$symbol} &&
+ $map->{$symbol}->body == $self->get_package_symbol('&' . $symbol);
+
+ $map->{$symbol} = $self->method_metaclass->wrap(
+ $self->get_package_symbol('&' . $symbol)
+ );
+ }
+
+ return $map;
+}
# Instance Construction & Cloning
# which will deal with the singletons
return $class->construct_class_instance(@_)
if $class->name->isa('Class::MOP::Class');
- bless $class->construct_instance(@_) => $class->name;
+ return $class->construct_instance(@_);
}
sub construct_instance {
my ($class, %params) = @_;
- my $instance = {};
+ my $meta_instance = $class->get_meta_instance();
+ my $instance = $meta_instance->create_instance();
foreach my $attr ($class->compute_all_applicable_attributes()) {
- my $init_arg = $attr->init_arg();
- # try to fetch the init arg from the %params ...
- my $val;
- $val = $params{$init_arg} if exists $params{$init_arg};
- # if nothing was in the %params, we can use the
- # attribute's default value (if it has one)
- $val ||= $attr->default($instance) if $attr->has_default();
- $instance->{$attr->name} = $val;
+ $attr->initialize_instance_slot($meta_instance, $instance, \%params);
}
return $instance;
}
+sub get_meta_instance {
+ my $class = shift;
+ return $class->instance_metaclass->new(
+ $class,
+ $class->compute_all_applicable_attributes()
+ );
+}
+
sub clone_object {
my $class = shift;
my $instance = shift;
# Class::MOP::Class singletons here, they
# should not be cloned.
return $instance if $instance->isa('Class::MOP::Class');
- bless $class->clone_instance($instance, @_) => blessed($instance);
+ $class->clone_instance($instance, @_);
}
sub clone_instance {
my ($class, $instance, %params) = @_;
(blessed($instance))
|| confess "You can only clone instances, \$self is not a blessed instance";
- # NOTE:
- # This will deep clone, which might
- # not be what you always want. So
- # the best thing is to write a more
- # controled &clone method locally
- # in the class (see Class::MOP)
- my $clone = Clone::clone($instance);
- foreach my $attr ($class->compute_all_applicable_attributes()) {
- my $init_arg = $attr->init_arg();
- # try to fetch the init arg from the %params ...
- $clone->{$attr->name} = $params{$init_arg}
- if exists $params{$init_arg};
+ my $meta_instance = $class->get_meta_instance();
+ my $clone = $meta_instance->clone_instance($instance);
+ foreach my $key (keys %params) {
+ next unless $meta_instance->is_valid_slot($key);
+ $meta_instance->set_slot_value($clone, $key, $params{$key});
}
return $clone;
}
-# Informational
-
-# &name should be here too, but it is above
-# because it gets bootstrapped away
-
-sub version {
- my $self = shift;
- no strict 'refs';
- ${$self->name . '::VERSION'};
-}
-
# Inheritance
sub superclasses {
my $self = shift;
- no strict 'refs';
if (@_) {
my @supers = @_;
- @{$self->name . '::ISA'} = @supers;
+ @{$self->get_package_symbol('@ISA')} = @supers;
+ # NOTE:
+ # we need to check the metaclass
+ # compatability here so that we can
+ # be sure that the superclass is
+ # not potentially creating an issues
+ # we don't know about
+ $self->check_metaclass_compatability();
}
- @{$self->name . '::ISA'};
+ @{$self->get_package_symbol('@ISA')};
}
sub class_precedence_list {
# This will do nothing if all is well, and blow
# up otherwise. Yes, it's an ugly hack, better
# suggestions are welcome.
- { $self->name->isa('This is a test for circular inheritance') }
- # ... and no back to our regularly scheduled program
+ { ($self->name || return)->isa('This is a test for circular inheritance') }
+ # ... and now back to our regularly scheduled program
(
$self->name,
map {
(defined $method_name && $method_name)
|| confess "You must define a method name";
# use reftype here to allow for blessed subs ...
- (reftype($method) && reftype($method) eq 'CODE')
- || confess "Your code block must be a CODE reference";
- my $full_method_name = ($self->name . '::' . $method_name);
+
+ my $body;
+
+ if (blessed($method)) {
+
+ $body = $method->body;
+
+ ('CODE' eq (reftype($body) || ''))
+ || confess "Your code block must be a CODE reference";
+
+ $self->get_method_map->{$method_name} = $method;
+ }
+ else {
+
+ $body = $method;
+
+ ('CODE' eq (reftype($body) || ''))
+ || confess "Your code block must be a CODE reference";
+
+ $self->get_method_map->{$method_name} = $self->method_metaclass->wrap($body);
- no strict 'refs';
- no warnings 'redefine';
- *{$full_method_name} = subname $full_method_name => $method;
+ }
+
+ my $full_method_name = ($self->name . '::' . $method_name);
+ $self->add_package_symbol("&${method_name}" => subname $full_method_name => $body);
}
{
-
- ## private utility functions for has_method
- my $_find_subroutine_package_name = sub { eval { svref_2object($_[0])->GV->STASH->NAME } || '' };
- my $_find_subroutine_name = sub { eval { svref_2object($_[0])->GV->NAME } || '' };
-
- sub has_method {
+ my $fetch_and_prepare_method = sub {
my ($self, $method_name) = @_;
+ # fetch it locally
+ my $method = $self->get_method($method_name);
+ # if we dont have local ...
+ unless ($method) {
+ # try to find the next method
+ $method = $self->find_next_method_by_name($method_name);
+ # die if it does not exist
+ (defined $method)
+ || confess "The method '$method_name' is not found in the inherience hierarchy for this class";
+ # and now make sure to wrap it
+ # even if it is already wrapped
+ # because we need a new sub ref
+ $method = Class::MOP::Method::Wrapped->wrap($method);
+ }
+ else {
+ # now make sure we wrap it properly
+ $method = Class::MOP::Method::Wrapped->wrap($method)
+ unless $method->isa('Class::MOP::Method::Wrapped');
+ }
+ $self->add_method($method_name => $method);
+ return $method;
+ };
+
+ sub add_before_method_modifier {
+ my ($self, $method_name, $method_modifier) = @_;
(defined $method_name && $method_name)
- || confess "You must define a method name";
+ || confess "You must pass in a method name";
+ my $method = $fetch_and_prepare_method->($self, $method_name);
+ $method->add_before_modifier(subname ':before' => $method_modifier);
+ }
+
+ sub add_after_method_modifier {
+ my ($self, $method_name, $method_modifier) = @_;
+ (defined $method_name && $method_name)
+ || confess "You must pass in a method name";
+ my $method = $fetch_and_prepare_method->($self, $method_name);
+ $method->add_after_modifier(subname ':after' => $method_modifier);
+ }
- my $sub_name = ($self->name . '::' . $method_name);
-
- no strict 'refs';
- return 0 if !defined(&{$sub_name});
- return 0 if $_find_subroutine_package_name->(\&{$sub_name}) ne $self->name &&
- $_find_subroutine_name->(\&{$sub_name}) ne '__ANON__';
- return 1;
+ sub add_around_method_modifier {
+ my ($self, $method_name, $method_modifier) = @_;
+ (defined $method_name && $method_name)
+ || confess "You must pass in a method name";
+ my $method = $fetch_and_prepare_method->($self, $method_name);
+ $method->add_around_modifier(subname ':around' => $method_modifier);
+ }
+
+ # NOTE:
+ # the methods above used to be named like this:
+ # ${pkg}::${method}:(before|after|around)
+ # but this proved problematic when using one modifier
+ # to wrap multiple methods (something which is likely
+ # to happen pretty regularly IMO). So instead of naming
+ # it like this, I have chosen to just name them purely
+ # with their modifier names, like so:
+ # :(before|after|around)
+ # The fact is that in a stack trace, it will be fairly
+ # evident from the context what method they are attached
+ # to, and so don't need the fully qualified name.
+}
+
+sub alias_method {
+ my ($self, $method_name, $method) = @_;
+ (defined $method_name && $method_name)
+ || confess "You must define a method name";
+
+ my $body;
+
+ if (blessed($method)) {
+
+ $body = $method->body;
+
+ ('CODE' eq (reftype($body) || ''))
+ || confess "Your code block must be a CODE reference";
+
+ $self->get_method_map->{$method_name} = $method;
+ }
+ else {
+
+ $body = $method;
+
+ ('CODE' eq (reftype($body) || ''))
+ || confess "Your code block must be a CODE reference";
+
+ $self->get_method_map->{$method_name} = $self->method_metaclass->wrap($body);
+
}
+
+ $self->add_package_symbol("&${method_name}" => $body);
+}
+sub has_method {
+ my ($self, $method_name) = @_;
+ (defined $method_name && $method_name)
+ || confess "You must define a method name";
+
+ my $method_map = $self->get_method_map;
+
+ return 0 unless exists $self->get_method_map->{$method_name};
+
+ my $method = $method_map->{$method_name};
+ return 0 if ($method->package_name || '') ne $self->name &&
+ ($method->name || '') ne '__ANON__';
+
+ return 1;
}
sub get_method {
my ($self, $method_name) = @_;
(defined $method_name && $method_name)
|| confess "You must define a method name";
-
- no strict 'refs';
- return \&{$self->name . '::' . $method_name}
- if $self->has_method($method_name);
- return; # <- make sure to return undef
+
+ return unless $self->has_method($method_name);
+
+ return $self->get_method_map->{$method_name};
}
sub remove_method {
my $removed_method = $self->get_method($method_name);
- no strict 'refs';
- delete ${$self->name . '::'}{$method_name}
+ $self->remove_package_symbol("&${method_name}")
if defined $removed_method;
+ delete $self->get_method_map->{$method_name}
+ if exists $self->get_method_map->{$method_name};
+
return $removed_method;
}
sub get_method_list {
my $self = shift;
- no strict 'refs';
- grep { $self->has_method($_) } %{$self->name . '::'};
+ return grep { $self->has_method($_) } keys %{$self->get_method_map};
+}
+
+sub find_method_by_name {
+ my ($self, $method_name) = @_;
+ # FIXME
+ return $self->name->can($method_name);
}
sub compute_all_applicable_methods {
} if $meta->has_method($method_name);
}
return @methods;
+}
+sub find_next_method_by_name {
+ my ($self, $method_name) = @_;
+ (defined $method_name && $method_name)
+ || confess "You must define a method name to find";
+ # keep a record of what we have seen
+ # here, this will handle all the
+ # inheritence issues because we are
+ # using the &class_precedence_list
+ my %seen_class;
+ my @cpl = $self->class_precedence_list();
+ shift @cpl; # discard ourselves
+ foreach my $class (@cpl) {
+ next if $seen_class{$class};
+ $seen_class{$class}++;
+ # fetch the meta-class ...
+ my $meta = $self->initialize($class);
+ return $meta->get_method($method_name)
+ if $meta->has_method($method_name);
+ }
+ return;
}
## Attributes
($attribute->isa('Class::MOP::Attribute'))
|| confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)";
$attribute->attach_to_class($self);
- $attribute->install_accessors();
+ $attribute->install_accessors();
$self->get_attribute_map->{$attribute->name} = $attribute;
}
(defined $attribute_name && $attribute_name)
|| confess "You must define an attribute name";
return $self->get_attribute_map->{$attribute_name}
- if $self->has_attribute($attribute_name);
+ if $self->has_attribute($attribute_name);
+ return;
}
sub remove_attribute {
(defined $attribute_name && $attribute_name)
|| confess "You must define an attribute name";
my $removed_attribute = $self->get_attribute_map->{$attribute_name};
- delete $self->get_attribute_map->{$attribute_name}
- if defined $removed_attribute;
- $removed_attribute->remove_accessors();
- $removed_attribute->detach_from_class();
+ return unless defined $removed_attribute;
+ delete $self->get_attribute_map->{$attribute_name};
+ $removed_attribute->remove_accessors();
+ $removed_attribute->detach_from_class();
return $removed_attribute;
}
return @attrs;
}
-# Class attributes
-
-sub add_package_variable {
- my ($self, $variable, $initial_value) = @_;
- (defined $variable && $variable =~ /^[\$\@\%]/)
- || confess "variable name does not have a sigil";
-
- my ($sigil, $name) = ($variable =~ /^(.)(.*)$/);
- if (defined $initial_value) {
- no strict 'refs';
- *{$self->name . '::' . $name} = $initial_value;
- }
- else {
- eval $sigil . $self->name . '::' . $name;
- confess "Could not create package variable ($variable) because : $@" if $@;
+sub find_attribute_by_name {
+ my ($self, $attr_name) = @_;
+ # keep a record of what we have seen
+ # here, this will handle all the
+ # inheritence issues because we are
+ # using the &class_precedence_list
+ my %seen_class;
+ foreach my $class ($self->class_precedence_list()) {
+ next if $seen_class{$class};
+ $seen_class{$class}++;
+ # fetch the meta-class ...
+ my $meta = $self->initialize($class);
+ return $meta->get_attribute($attr_name)
+ if $meta->has_attribute($attr_name);
}
+ return;
}
-sub has_package_variable {
- my ($self, $variable) = @_;
- (defined $variable && $variable =~ /^[\$\@\%]/)
- || confess "variable name does not have a sigil";
- my ($sigil, $name) = ($variable =~ /^(.)(.*)$/);
- no strict 'refs';
- defined ${$self->name . '::'}{$name} ? 1 : 0;
-}
+## Class closing
-sub get_package_variable {
- my ($self, $variable) = @_;
- (defined $variable && $variable =~ /^[\$\@\%]/)
- || confess "variable name does not have a sigil";
- my ($sigil, $name) = ($variable =~ /^(.)(.*)$/);
- no strict 'refs';
- # try to fetch it first,.. see what happens
- eval '\\' . $sigil . $self->name . '::' . $name;
- confess "Could not get the package variable ($variable) because : $@" if $@;
- # if we didn't die, then we can return it
- # NOTE:
- # this is not ideal, better suggestions are welcome
- eval '\\' . $sigil . $self->name . '::' . $name;
-}
+sub is_mutable { 1 }
+sub is_immutable { 0 }
-sub remove_package_variable {
- my ($self, $variable) = @_;
- (defined $variable && $variable =~ /^[\$\@\%]/)
- || confess "variable name does not have a sigil";
- my ($sigil, $name) = ($variable =~ /^(.)(.*)$/);
- no strict 'refs';
- delete ${$self->name . '::'}{$name};
+sub make_immutable {
+ return Class::MOP::Class::Immutable->make_metaclass_immutable(@_);
}
1;
=head1 SYNOPSIS
- # use this for introspection ...
+ # assuming that class Foo
+ # has been defined, you can
- package Foo;
- sub meta { Class::MOP::Class->initialize(__PACKAGE__) }
-
- # elsewhere in the code ...
+ # use this for introspection ...
# add a method to Foo ...
Foo->meta->add_method('bar' => sub { ... })
# or use this to actually create classes ...
- Class::MOP::Class->create('Bar' => '0.01' => (
+ Class::MOP::Class->create('Bar' => (
+ version => '0.01',
superclasses => [ 'Foo' ],
attributes => [
Class::MOP:::Attribute->new('$bar'),
=over 4
-=item B<create ($package_name, ?$package_version,
+=item B<create ($package_name,
+ version =E<gt> ?$version,
+ authority =E<gt> ?$authority,
superclasses =E<gt> ?@superclasses,
methods =E<gt> ?%methods,
attributes =E<gt> ?%attributes)>
This returns a B<Class::MOP::Class> object, bringing the specified
-C<$package_name> into existence and adding any of the
-C<$package_version>, C<@superclasses>, C<%methods> and C<%attributes>
-to it.
+C<$package_name> into existence and adding any of the C<$version>,
+C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to
+it.
+
+=item B<create_anon_class (superclasses =E<gt> ?@superclasses,
+ methods =E<gt> ?%methods,
+ attributes =E<gt> ?%attributes)>
-=item B<initialize ($package_name)>
+This will create an anonymous class, it works much like C<create> but
+it does not need a C<$package_name>. Instead it will create a suitably
+unique package name for you to stash things into.
+
+=item B<initialize ($package_name, %options)>
This initializes and returns returns a B<Class::MOP::Class> object
for a given a C<$package_name>.
+=item B<reinitialize ($package_name, %options)>
+
+This removes the old metaclass, and creates a new one in it's place.
+Do B<not> use this unless you really know what you are doing, it could
+very easily make a very large mess of your program.
+
=item B<construct_class_instance (%options)>
This will construct an instance of B<Class::MOP::Class>, it is
method is used internally by C<initialize> and should never be called
from outside of that method really.
+=item B<check_metaclass_compatability>
+
+This method is called as the very last thing in the
+C<construct_class_instance> method. This will check that the
+metaclass you are creating is compatible with the metaclasses of all
+your ancestors. For more inforamtion about metaclass compatibility
+see the C<About Metaclass compatibility> section in L<Class::MOP>.
+
=back
=head2 Object instance construction and cloning
=over 4
+=item B<instance_metaclass>
+
+=item B<get_meta_instance>
+
=item B<new_object (%params)>
This is a convience method for creating a new object of the class, and
=item B<clone_object ($instance, %params)>
This is a convience method for cloning an object instance, then
-blessing it into the appropriate package. Ideally your class
-would call a C<clone> this method like so:
+blessing it into the appropriate package. This method will call
+C<clone_instance>, which performs a shallow copy of the object,
+see that methods documentation for more details. Ideally your
+class would call a C<clone> this method like so:
sub MyClass::clone {
my ($self, %param) = @_;
=item B<clone_instance($instance, %params)>
This method is a compliment of C<construct_instance> (which means if
-you override C<construct_instance>, you need to override this one too).
+you override C<construct_instance>, you need to override this one too),
+and clones the instance shallowly.
+
+The cloned structure returned is (like with C<construct_instance>) an
+unC<bless>ed HASH reference, it is your responsibility to then bless
+this cloned structure into the right class (which C<clone_object> will
+do for you).
-This method will clone the C<$instance> structure created by the
-C<construct_instance> method, and apply any C<%params> passed to it
-to change the attribute values. The structure returned is (like with
-C<construct_instance>) an unC<bless>ed HASH reference, it is your
-responsibility to then bless this cloned structure into the right
-class.
+As of 0.11, this method will clone the C<$instance> structure shallowly,
+as opposed to the deep cloning implemented in prior versions. After much
+thought, research and discussion, I have decided that anything but basic
+shallow cloning is outside the scope of the meta-object protocol. I
+think Yuval "nothingmuch" Kogman put it best when he said that cloning
+is too I<context-specific> to be part of the MOP.
=back
=head2 Informational
-=over 4
+These are a few predicate methods for asking information about the class.
-=item B<name>
+=over 4
-This is a read-only attribute which returns the package name for the
-given B<Class::MOP::Class> instance.
+=item B<is_anon_class>
-=item B<version>
+=item B<is_mutable>
-This is a read-only attribute which returns the C<$VERSION> of the
-package for the given B<Class::MOP::Class> instance.
+=item B<is_immutable>
=back
=over 4
+=item B<get_method_map>
+
=item B<method_metaclass>
=item B<add_method ($method_name, $method)>
correct name, and therefore show up correctly in stack traces and
such.
+=item B<alias_method ($method_name, $method)>
+
+This will take a C<$method_name> and CODE reference to that
+C<$method> and alias the method into the class's package.
+
+B<NOTE>:
+Unlike C<add_method>, this will B<not> try to name the
+C<$method> using B<Sub::Name>, it only aliases the method in
+the class's package.
+
=item B<has_method ($method_name)>
This just provides a simple way to check if the class implements
This will return a CODE reference of the specified C<$method_name>,
or return undef if that method does not exist.
+=item B<find_method_by_name ($method_name>
+
+This will return a CODE reference of the specified C<$method_name>,
+or return undef if that method does not exist.
+
+Unlike C<get_method> this will also look in the superclasses.
+
=item B<remove_method ($method_name)>
This will attempt to remove a given C<$method_name> from the class.
initialization and destruction where you only want the method called
once, and in the correct order.
+=item B<find_next_method_by_name ($method_name)>
+
+This will return the first method to match a given C<$method_name> in
+the superclasses, this is basically equivalent to calling
+C<SUPER::$method_name>, but it can be dispatched at runtime.
+
+=back
+
+=head2 Method Modifiers
+
+Method modifiers are a concept borrowed from CLOS, in which a method
+can be wrapped with I<before>, I<after> and I<around> method modifiers
+that will be called everytime the method is called.
+
+=head3 How method modifiers work?
+
+Method modifiers work by wrapping the original method and then replacing
+it in the classes symbol table. The wrappers will handle calling all the
+modifiers in the appropariate orders and preserving the calling context
+for the original method.
+
+Each method modifier serves a particular purpose, which may not be
+obvious to users of other method wrapping modules. To start with, the
+return values of I<before> and I<after> modifiers are ignored. This is
+because thier purpose is B<not> to filter the input and output of the
+primary method (this is done with an I<around> modifier). This may seem
+like an odd restriction to some, but doing this allows for simple code
+to be added at the begining or end of a method call without jeapordizing
+the normal functioning of the primary method or placing any extra
+responsibility on the code of the modifier. Of course if you have more
+complex needs, then use the I<around> modifier, which uses a variation
+of continutation passing style to allow for a high degree of flexibility.
+
+Before and around modifiers are called in last-defined-first-called order,
+while after modifiers are called in first-defined-first-called order. So
+the call tree might looks something like this:
+
+ before 2
+ before 1
+ around 2
+ around 1
+ primary
+ after 1
+ after 2
+
+To see examples of using method modifiers, see the following examples
+included in the distribution; F<InstanceCountingClass>, F<Perl6Attribute>,
+F<AttributesWithHistory> and F<C3MethodDispatchOrder>. There is also a
+classic CLOS usage example in the test F<017_add_method_modifier.t>.
+
+=head3 What is the performance impact?
+
+Of course there is a performance cost associated with method modifiers,
+but we have made every effort to make that cost be directly proportional
+to the amount of modifier features you utilize.
+
+The wrapping method does it's best to B<only> do as much work as it
+absolutely needs to. In order to do this we have moved some of the
+performance costs to set-up time, where they are easier to amortize.
+
+All this said, my benchmarks have indicated the following:
+
+ simple wrapper with no modifiers 100% slower
+ simple wrapper with simple before modifier 400% slower
+ simple wrapper with simple after modifier 450% slower
+ simple wrapper with simple around modifier 500-550% slower
+ simple wrapper with all 3 modifiers 1100% slower
+
+These numbers may seem daunting, but you must remember, every feature
+comes with some cost. To put things in perspective, just doing a simple
+C<AUTOLOAD> which does nothing but extract the name of the method called
+and return it costs about 400% over a normal method call.
+
+=over 4
+
+=item B<add_before_method_modifier ($method_name, $code)>
+
+This will wrap the method at C<$method_name> and the supplied C<$code>
+will be passed the C<@_> arguments, and called before the original
+method is called. As specified above, the return value of the I<before>
+method modifiers is ignored, and it's ability to modify C<@_> is
+fairly limited. If you need to do either of these things, use an
+C<around> method modifier.
+
+=item B<add_after_method_modifier ($method_name, $code)>
+
+This will wrap the method at C<$method_name> so that the original
+method will be called, it's return values stashed, and then the
+supplied C<$code> will be passed the C<@_> arguments, and called.
+As specified above, the return value of the I<after> method
+modifiers is ignored, and it cannot modify the return values of
+the original method. If you need to do either of these things, use an
+C<around> method modifier.
+
+=item B<add_around_method_modifier ($method_name, $code)>
+
+This will wrap the method at C<$method_name> so that C<$code>
+will be called and passed the original method as an extra argument
+at the begining of the C<@_> argument list. This is a variation of
+continuation passing style, where the function prepended to C<@_>
+can be considered a continuation. It is up to C<$code> if it calls
+the original method or not, there is no restriction on what the
+C<$code> can or cannot do.
+
=back
=head2 Attributes
that same information is discoverable through the attribute
meta-object itself.
-=back
-
-=head2 Package Variables
-
-Since Perl's classes are built atop the Perl package system, it is
-fairly common to use package scoped variables for things like static
-class variables. The following methods are convience methods for
-the creation and inspection of package scoped variables.
-
-=over 4
-
-=item B<add_package_variable ($variable_name, ?$initial_value)>
-
-Given a C<$variable_name>, which must contain a leading sigil, this
-method will create that variable within the package which houses the
-class. It also takes an optional C<$initial_value>, which must be a
-reference of the same type as the sigil of the C<$variable_name>
-implies.
-
-=item B<get_package_variable ($variable_name)>
+=item B<find_attribute_by_name ($attr_name)>
-This will return a reference to the package variable in
-C<$variable_name>.
+This method will traverse the inheritance heirachy and find the
+first attribute whose name matches C<$attr_name>, then return it.
+It will return undef if nothing is found.
-=item B<has_package_variable ($variable_name)>
+=back
-Returns true (C<1>) if there is a package variable defined for
-C<$variable_name>, and false (C<0>) otherwise.
+=head2 Class closing
-=item B<remove_package_variable ($variable_name)>
+=over 4
-This will attempt to remove the package variable at C<$variable_name>.
+=item B<make_immutable>
=back
-=head1 AUTHOR
+=head1 AUTHORS
Stevan Little E<lt>stevan@iinteractive.comE<gt>
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
+
=head1 COPYRIGHT AND LICENSE
Copyright 2006 by Infinity Interactive, Inc.
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
-=cut
\ No newline at end of file
+=cut
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