use strict;
use warnings;
-our $VERSION = '0.05';
+use 5.008;
-use Scalar::Util 'blessed', 'reftype';
+our $VERSION = '0.73';
+$VERSION = eval $VERSION;
+our $AUTHORITY = 'cpan:STEVAN';
+
+use Scalar::Util 'blessed';
use Carp 'confess';
-use Sub::Name 'subname';
-use UNIVERSAL::require;
-use Sub::Exporter;
+use Moose::Exporter;
-use Class::MOP;
+use Class::MOP 0.78_02;
use Moose::Meta::Class;
use Moose::Meta::TypeConstraint;
use Moose::Meta::Instance;
use Moose::Object;
+
+use Moose::Meta::Role;
+use Moose::Meta::Role::Composite;
+use Moose::Meta::Role::Application;
+use Moose::Meta::Role::Application::RoleSummation;
+use Moose::Meta::Role::Application::ToClass;
+use Moose::Meta::Role::Application::ToRole;
+use Moose::Meta::Role::Application::ToInstance;
+
use Moose::Util::TypeConstraints;
+use Moose::Util ();
+
+sub _caller_info {
+ my $level = @_ ? ($_[0] + 1) : 2;
+ my %info;
+ @info{qw(package file line)} = caller($level);
+ return \%info;
+}
+
+sub throw_error {
+ # FIXME This
+ shift;
+ goto \&confess
+}
+
+sub extends {
+ my $class = shift;
+
+ Moose->throw_error("Must derive at least one class") unless @_;
+
+ my @supers = @_;
+ foreach my $super (@supers) {
+ my $meta = Class::MOP::load_class($super);
+ Moose->throw_error("You cannot inherit from a Moose Role ($super)")
+ if $meta && $meta->isa('Moose::Meta::Role')
+ }
-{
- my ( $CALLER, %METAS );
- sub _find_meta {
- my $class = $CALLER;
- return $METAS{$class} if exists $METAS{$class};
+ # this checks the metaclass to make sure
+ # it is correct, sometimes it can get out
+ # of sync when the classes are being built
+ my $meta = Moose::Meta::Class->initialize($class);
+ $meta->superclasses(@supers);
+}
+
+sub with {
+ my $class = shift;
+ Moose::Util::apply_all_roles(Class::MOP::Class->initialize($class), @_);
+}
+
+sub has {
+ my $class = shift;
+ my $name = shift;
+
+ Moose->throw_error('Usage: has \'name\' => ( key => value, ... )')
+ if @_ == 1;
+
+ my %options = ( definition_context => _caller_info(), @_ );
+ my $attrs = ( ref($name) eq 'ARRAY' ) ? $name : [ ($name) ];
+ Class::MOP::Class->initialize($class)->add_attribute( $_, %options ) for @$attrs;
+}
- # make a subtype for each Moose class
- subtype $class
- => as 'Object'
- => where { $_->isa($class) }
+sub before {
+ my $class = shift;
+ Moose::Util::add_method_modifier($class, 'before', \@_);
+}
+
+sub after {
+ my $class = shift;
+ Moose::Util::add_method_modifier($class, 'after', \@_);
+}
+
+sub around {
+ my $class = shift;
+ Moose::Util::add_method_modifier($class, 'around', \@_);
+}
+
+our $SUPER_PACKAGE;
+our $SUPER_BODY;
+our @SUPER_ARGS;
+
+sub super {
+ # This check avoids a recursion loop - see
+ # t/100_bugs/020_super_recursion.t
+ return if defined $SUPER_PACKAGE && $SUPER_PACKAGE ne caller();
+ return unless $SUPER_BODY; $SUPER_BODY->(@SUPER_ARGS);
+}
+
+sub override {
+ my $class = shift;
+ my ( $name, $method ) = @_;
+ Class::MOP::Class->initialize($class)->add_override_method_modifier( $name => $method );
+}
+
+sub inner {
+ my $pkg = caller();
+ our ( %INNER_BODY, %INNER_ARGS );
+
+ if ( my $body = $INNER_BODY{$pkg} ) {
+ my @args = @{ $INNER_ARGS{$pkg} };
+ local $INNER_ARGS{$pkg};
+ local $INNER_BODY{$pkg};
+ return $body->(@args);
+ } else {
+ return;
+ }
+}
+
+sub augment {
+ my $class = shift;
+ my ( $name, $method ) = @_;
+ Class::MOP::Class->initialize($class)->add_augment_method_modifier( $name => $method );
+}
+
+Moose::Exporter->setup_import_methods(
+ with_caller => [
+ qw( extends with has before after around override augment)
+ ],
+ as_is => [
+ qw( super inner ),
+ \&Carp::confess,
+ \&Scalar::Util::blessed,
+ ],
+);
+
+sub init_meta {
+ # This used to be called as a function. This hack preserves
+ # backwards compatibility.
+ if ( $_[0] ne __PACKAGE__ ) {
+ return __PACKAGE__->init_meta(
+ for_class => $_[0],
+ base_class => $_[1],
+ metaclass => $_[2],
+ );
+ }
+
+ shift;
+ my %args = @_;
+
+ my $class = $args{for_class}
+ or Moose->throw_error("Cannot call init_meta without specifying a for_class");
+ my $base_class = $args{base_class} || 'Moose::Object';
+ my $metaclass = $args{metaclass} || 'Moose::Meta::Class';
+
+ Moose->throw_error("The Metaclass $metaclass must be a subclass of Moose::Meta::Class.")
+ unless $metaclass->isa('Moose::Meta::Class');
+
+ # make a subtype for each Moose class
+ class_type($class)
unless find_type_constraint($class);
- my $meta;
- if ($class->can('meta')) {
- $meta = $class->meta();
- (blessed($meta) && $meta->isa('Moose::Meta::Class'))
- || confess "Whoops, not møøsey enough";
- }
- else {
- $meta = Moose::Meta::Class->initialize($class);
- $meta->add_method('meta' => sub {
- # re-initialize so it inherits properly
- Moose::Meta::Class->initialize(blessed($_[0]) || $_[0]);
- })
+ my $meta;
+
+ if ( $meta = Class::MOP::get_metaclass_by_name($class) ) {
+ unless ( $meta->isa("Moose::Meta::Class") ) {
+ Moose->throw_error("$class already has a metaclass, but it does not inherit $metaclass ($meta)");
}
+ } else {
+ # no metaclass, no 'meta' method
- # make sure they inherit from Moose::Object
- $meta->superclasses('Moose::Object')
- unless $meta->superclasses();
+ # now we check whether our ancestors have metaclass, and if so borrow that
+ my ( undef, @isa ) = @{ $class->mro::get_linear_isa };
- return $METAS{$class} = $meta;
- }
+ foreach my $ancestor ( @isa ) {
+ my $ancestor_meta = Class::MOP::get_metaclass_by_name($ancestor) || next;
- my %exports = (
- extends => sub {
- my $meta = _find_meta();
- return subname 'Moose::extends' => sub {
- _load_all_classes(@_);
- $meta->superclasses(@_)
- };
- },
- with => sub {
- my $meta = _find_meta();
- return subname 'Moose::with' => sub {
- my ($role) = @_;
- _load_all_classes($role);
- $role->meta->apply($meta);
- };
- },
- has => sub {
- my $meta = _find_meta();
- return subname 'Moose::has' => sub {
- my ($name, %options) = @_;
- if ($name =~ /^\+(.*)/) {
- my $inherited_attr = $meta->find_attribute_by_name($1);
- (defined $inherited_attr)
- || confess "Could not find an attribute by the name of '$1' to inherit from";
- my $new_attr = $inherited_attr->clone_and_inherit_options(%options);
- $meta->add_attribute($new_attr);
- }
- else {
- if ($options{metaclass}) {
- _load_all_classes($options{metaclass});
- $meta->add_attribute($options{metaclass}->new($name, %options));
- }
- else {
- $meta->add_attribute($name, %options);
- }
- }
- };
- },
- before => sub {
- my $meta = _find_meta();
- return subname 'Moose::before' => sub {
- my $code = pop @_;
- $meta->add_before_method_modifier($_, $code) for @_;
- };
- },
- after => sub {
- my $meta = _find_meta();
- return subname 'Moose::after' => sub {
- my $code = pop @_;
- $meta->add_after_method_modifier($_, $code) for @_;
- };
- },
- around => sub {
- my $meta = _find_meta();
- return subname 'Moose::around' => sub {
- my $code = pop @_;
- $meta->add_around_method_modifier($_, $code) for @_;
- };
- },
- super => sub {
- my $meta = _find_meta();
- return subname 'Moose::super' => sub {};
- },
- override => sub {
- my $meta = _find_meta();
- return subname 'Moose::override' => sub {
- my ($name, $method) = @_;
- $meta->add_override_method_modifier($name => $method);
- };
- },
- inner => sub {
- my $meta = _find_meta();
- return subname 'Moose::inner' => sub {};
- },
- augment => sub {
- my $meta = _find_meta();
- return subname 'Moose::augment' => sub {
- my ($name, $method) = @_;
- $meta->add_augment_method_modifier($name => $method);
- };
- },
- confess => sub {
- return \&Carp::confess;
- },
- blessed => sub {
- return \&Scalar::Util::blessed;
- },
- all_methods => sub {
- sub () {
- sub {
- my ( $class, $delegate_class ) = @_;
- $delegate_class->compute_all_applicable_methods();
+ my $ancestor_meta_class = ($ancestor_meta->is_immutable
+ ? $ancestor_meta->get_mutable_metaclass_name
+ : ref($ancestor_meta));
+
+ # if we have an ancestor metaclass that inherits $metaclass, we use
+ # that. This is like _fix_metaclass_incompatibility, but we can do it now.
+
+ # the case of having an ancestry is not very common, but arises in
+ # e.g. Reaction
+ unless ( $metaclass->isa( $ancestor_meta_class ) ) {
+ if ( $ancestor_meta_class->isa($metaclass) ) {
+ $metaclass = $ancestor_meta_class;
}
}
}
- );
- my $exporter = Sub::Exporter::build_exporter({
- exports => \%exports,
- groups => {
- default => [':all']
- }
- });
-
- sub import {
- $CALLER = caller();
+ $meta = $metaclass->initialize($class);
+ }
+
+ if ( $class->can('meta') ) {
+ # check 'meta' method
+
+ # it may be inherited
+
+ # NOTE:
+ # this is the case where the metaclass pragma
+ # was used before the 'use Moose' statement to
+ # override a specific class
+ my $method_meta = $class->meta;
- # we should never export to main
- return if $CALLER eq 'main';
+ ( blessed($method_meta) && $method_meta->isa('Moose::Meta::Class') )
+ || Moose->throw_error("$class already has a &meta function, but it does not return a Moose::Meta::Class ($meta)");
- goto $exporter;
+ $meta = $method_meta;
+ }
+
+ unless ( $meta->has_method("meta") ) { # don't overwrite
+ # also check for inherited non moose 'meta' method?
+ # FIXME also skip this if the user requested by passing an option
+ $meta->add_method(
+ 'meta' => sub {
+ # re-initialize so it inherits properly
+ $metaclass->initialize( ref($_[0]) || $_[0] );
+ }
+ );
}
-}
-## Utility functions
-
-sub _load_all_classes {
- foreach my $super (@_) {
- # see if this is already
- # loaded in the symbol table
- next if _is_class_already_loaded($super);
- # otherwise require it ...
- ($super->require)
- || confess "Could not load superclass '$super' because : " . $UNIVERSAL::require::ERROR;
- }
+ # make sure they inherit from Moose::Object
+ $meta->superclasses($base_class)
+ unless $meta->superclasses();
+
+ return $meta;
}
-sub _is_class_already_loaded {
- my $name = shift;
- no strict 'refs';
- return 1 if defined ${"${name}::VERSION"} || defined @{"${name}::ISA"};
- foreach (keys %{"${name}::"}) {
- next if substr($_, -2, 2) eq '::';
- return 1 if defined &{"${name}::$_"};
- }
- return 0;
+# This may be used in some older MooseX extensions.
+sub _get_caller {
+ goto &Moose::Exporter::_get_caller;
}
+## make 'em all immutable
+
+$_->make_immutable(
+ inline_constructor => 1,
+ constructor_name => "_new",
+ # these are Class::MOP accessors, so they need inlining
+ inline_accessors => 1
+ ) for grep { $_->is_mutable }
+ map { $_->meta }
+ qw(
+ Moose::Meta::Attribute
+ Moose::Meta::Class
+ Moose::Meta::Instance
+
+ Moose::Meta::TypeCoercion
+ Moose::Meta::TypeCoercion::Union
+
+ Moose::Meta::Method
+ Moose::Meta::Method::Accessor
+ Moose::Meta::Method::Constructor
+ Moose::Meta::Method::Destructor
+ Moose::Meta::Method::Overridden
+ Moose::Meta::Method::Augmented
+
+ Moose::Meta::Role
+ Moose::Meta::Role::Method
+ Moose::Meta::Role::Method::Required
+
+ Moose::Meta::Role::Composite
+
+ Moose::Meta::Role::Application
+ Moose::Meta::Role::Application::RoleSummation
+ Moose::Meta::Role::Application::ToClass
+ Moose::Meta::Role::Application::ToRole
+ Moose::Meta::Role::Application::ToInstance
+);
+
1;
__END__
=head1 NAME
-Moose - Moose, it's the new Camel
+Moose - A postmodern object system for Perl 5
=head1 SYNOPSIS
package Point;
- use Moose;
-
- has 'x' => (isa => 'Int', is => 'rw');
- has 'y' => (isa => 'Int', is => 'rw');
-
+ use Moose; # automatically turns on strict and warnings
+
+ has 'x' => (is => 'rw', isa => 'Int');
+ has 'y' => (is => 'rw', isa => 'Int');
+
sub clear {
my $self = shift;
$self->x(0);
- $self->y(0);
+ $self->y(0);
}
-
+
package Point3D;
use Moose;
-
+
extends 'Point';
-
- has 'z' => (isa => 'Int');
-
+
+ has 'z' => (is => 'rw', isa => 'Int');
+
after 'clear' => sub {
my $self = shift;
- $self->{z} = 0;
+ $self->z(0);
};
-
-=head1 CAVEAT
-
-This is an early release of this module, it still needs
-some fine tuning and B<lots> more documentation. I am adopting
-the I<release early and release often> approach with this module,
-so keep an eye on your favorite CPAN mirror!
=head1 DESCRIPTION
-Moose is an extension of the Perl 5 object system.
+Moose is an extension of the Perl 5 object system.
-=head2 Another object system!?!?
+The main goal of Moose is to make Perl 5 Object Oriented programming
+easier, more consistent and less tedious. With Moose you can to think
+more about what you want to do and less about the mechanics of OOP.
-Yes, I know there has been an explosion recently of new ways to
-build object's in Perl 5, most of them based on inside-out objects,
-and other such things. Moose is different because it is not a new
-object system for Perl 5, but instead an extension of the existing
-object system.
+Additionally, Moose is built on top of L<Class::MOP>, which is a
+metaclass system for Perl 5. This means that Moose not only makes
+building normal Perl 5 objects better, but it provides the power of
+metaclass programming as well.
-Moose is built on top of L<Class::MOP>, which is a metaclass system
-for Perl 5. This means that Moose not only makes building normal
-Perl 5 objects better, but it also provides the power of metaclass
-programming.
+=head2 New to Moose?
-=head2 What does Moose stand for??
+If you're new to Moose, the best place to start is the
+L<Moose::Manual> docs, followed by the L<Moose::Cookbook>. The intro
+will show you what Moose is, and how it makes Perl 5 OO better.
-Moose doesn't stand for one thing in particular, however, if you
-want, here are a few of my favorites, feel free to contribute
-more :)
-
-=over 4
+The cookbook recipes on Moose basics will get you up to speed with
+many of Moose's features quickly. Once you have an idea of what Moose
+can do, you can use the API documentation to get more detail on
+features which interest you.
-=item Make Other Object Systems Envious
+=head2 Moose Extensions
-=item Makes Object Orientation So Easy
+The C<MooseX::> namespace is the official place to find Moose extensions.
+These extensions can be found on the CPAN. The easiest way to find them
+is to search for them (L<http://search.cpan.org/search?query=MooseX::>),
+or to examine L<Task::Moose> which aims to keep an up-to-date, easily
+installable list of Moose extensions.
-=item Makes Object Orientation Spiffy- Er (sorry ingy)
-
-=item Most Other Object Systems Emasculate
-
-=item My Overcraft Overfilled (with) Some Eels
+=head1 BUILDING CLASSES WITH MOOSE
-=item Moose Often Ovulate Sorta Early
+Moose makes every attempt to provide as much convenience as possible during
+class construction/definition, but still stay out of your way if you want it
+to. Here are a few items to note when building classes with Moose.
-=item Many Overloaded Object Systems Exists
+Unless specified with C<extends>, any class which uses Moose will
+inherit from L<Moose::Object>.
-=item Moose Offers Often Super Extensions
+Moose will also manage all attributes (including inherited ones) that are
+defined with C<has>. And (assuming you call C<new>, which is inherited from
+L<Moose::Object>) this includes properly initializing all instance slots,
+setting defaults where appropriate, and performing any type constraint checking
+or coercion.
-=item Meta Object Orientation Syntax Extensions
+=head1 PROVIDED METHODS
-=back
+Moose provides a number of methods to all your classes, mostly through the
+inheritance of L<Moose::Object>. There is however, one exception.
-=head1 BUILDING CLASSES WITH MOOSE
-
-Moose makes every attempt to provide as much convience during class
-construction/definition, but still stay out of your way if you want
-it to. Here are some of the features Moose provides:
+=over 4
-Unless specified with C<extends>, any class which uses Moose will
-inherit from L<Moose::Object>.
+=item B<meta>
-Moose will also manage all attributes (including inherited ones) that
-are defined with C<has>. And assuming that you call C<new> which is
-inherited from L<Moose::Object>, then this includes properly initializing
-all instance slots, setting defaults where approprtiate and performing any
-type constraint checking or coercion.
+This is a method which provides access to the current class's metaclass.
-For more details, see the ever expanding L<Moose::Cookbook>.
+=back
=head1 EXPORTED FUNCTIONS
-Moose will export a number of functions into the class's namespace, which
-can then be used to set up the class. These functions all work directly
+Moose will export a number of functions into the class's namespace which
+may then be used to set up the class. These functions all work directly
on the current class.
=over 4
-=item B<meta>
-
-This is a method which provides access to the current class's metaclass.
-
=item B<extends (@superclasses)>
This function will set the superclass(es) for the current class.
-This approach is recommended instead of C<use base>, because C<use base>
-actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
-replace it. This is important to ensure that classes which do not have
-superclasses properly inherit from L<Moose::Object>.
+This approach is recommended instead of C<use base>, because C<use base>
+actually C<push>es onto the class's C<@ISA>, whereas C<extends> will
+replace it. This is important to ensure that classes which do not have
+superclasses still properly inherit from L<Moose::Object>.
-=item B<with ($role)>
+=item B<with (@roles)>
-This will apply a given C<$role> to the local class. Role support is
-currently very experimental, see L<Moose::Role> for more details.
+This will apply a given set of C<@roles> to the local class.
-=item B<has ($name, %options)>
+=item B<has $name|@$names =E<gt> %options>
-This will install an attribute of a given C<$name> into the current class.
-The list of C<%options> are the same as those provided by both
-L<Class::MOP::Attribute> and L<Moose::Meta::Attribute>, in addition to a
-few convience ones provided by Moose which are listed below:
+This will install an attribute of a given C<$name> into the current class. If
+the first parameter is an array reference, it will create an attribute for
+every C<$name> in the list. The C<%options> are the same as those provided by
+L<Class::MOP::Attribute>, in addition to the list below which are provided by
+Moose (L<Moose::Meta::Attribute> to be more specific):
=over 4
=item I<is =E<gt> 'rw'|'ro'>
-The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
-only). These will create either a read/write accessor or a read-only
+The I<is> option accepts either I<rw> (for read/write) or I<ro> (for read
+only). These will create either a read/write accessor or a read-only
accessor respectively, using the same name as the C<$name> of the attribute.
-If you need more control over how your accessors are named, you can use the
-I<reader>, I<writer> and I<accessor> options inherited from L<Moose::Meta::Attribute>.
+If you need more control over how your accessors are named, you can
+use the L<reader|Class::MOP::Attribute/reader>,
+L<writer|Class::MOP::Attribute/writer> and
+L<accessor|Class::MOP::Attribute/accessor> options inherited from
+L<Class::MOP::Attribute>, however if you use those, you won't need the
+I<is> option.
=item I<isa =E<gt> $type_name>
-The I<isa> option uses Moose's type constraint facilities to set up runtime
-type checking for this attribute. Moose will perform the checks during class
-construction, and within any accessors. The C<$type_name> argument must be a
-string. The string can be either a class name, or a type defined using
-Moose's type defintion features.
+The I<isa> option uses Moose's type constraint facilities to set up runtime
+type checking for this attribute. Moose will perform the checks during class
+construction, and within any accessors. The C<$type_name> argument must be a
+string. The string may be either a class name or a type defined using
+Moose's type definition features. (Refer to L<Moose::Util::TypeConstraints>
+for information on how to define a new type, and how to retrieve type meta-data).
=item I<coerce =E<gt> (1|0)>
-This will attempt to use coercion with the supplied type constraint to change
-the value passed into any accessors of constructors. You B<must> have supplied
-a type constraint in order for this to work. See L<Moose::Cookbook::Recipe5>
-for an example usage.
+This will attempt to use coercion with the supplied type constraint to change
+the value passed into any accessors or constructors. You B<must> have supplied
+a type constraint in order for this to work. See L<Moose::Cookbook::Basics::Recipe5>
+for an example.
=item I<does =E<gt> $role_name>
-This will accept the name of a role which the value stored in this attribute
+This will accept the name of a role which the value stored in this attribute
is expected to have consumed.
=item I<required =E<gt> (1|0)>
-This marks the attribute as being required. This means a value must be supplied
-during class construction, and the attribute can never be set to C<undef> with
-an accessor.
+This marks the attribute as being required. This means a I<defined> value must be
+supplied during class construction, and the attribute may never be set to
+C<undef> with an accessor.
=item I<weak_ref =E<gt> (1|0)>
-This will tell the class to strore the value of this attribute as a weakened
-reference. If an attribute is a weakened reference, it can B<not> also be coerced.
+This will tell the class to store the value of this attribute as a weakened
+reference. If an attribute is a weakened reference, it B<cannot> also be
+coerced.
=item I<lazy =E<gt> (1|0)>
-This will tell the class to not create this slot until absolutely nessecary.
+This will tell the class to not create this slot until absolutely necessary.
If an attribute is marked as lazy it B<must> have a default supplied.
+=item I<auto_deref =E<gt> (1|0)>
+
+This tells the accessor whether to automatically dereference the value returned.
+This is only legal if your C<isa> option is either C<ArrayRef> or C<HashRef>.
+
=item I<trigger =E<gt> $code>
-The trigger option is a CODE reference which will be called after the value of
-the attribute is set. The CODE ref will be passed the instance itself, the
-updated value and the attribute meta-object (this is for more advanced fiddling
-and can typically be ignored in most cases). You can B<not> have a trigger on
+The I<trigger> option is a CODE reference which will be called after
+the value of the attribute is set. The CODE ref will be passed the
+instance itself and the updated value. You B<cannot> have a trigger on
a read-only attribute.
+B<NOTE:> Triggers will only fire when you B<assign> to the attribute,
+either in the constructor, or using the writer. Default and built values will
+B<not> cause the trigger to be fired.
+
+=item I<handles =E<gt> ARRAY | HASH | REGEXP | ROLE | CODE>
+
+The I<handles> option provides Moose classes with automated delegation features.
+This is a pretty complex and powerful option. It accepts many different option
+formats, each with its own benefits and drawbacks.
+
+B<NOTE:> The class being delegated to does not need to be a Moose based class,
+which is why this feature is especially useful when wrapping non-Moose classes.
+
+All I<handles> option formats share the following traits:
+
+You cannot override a locally defined method with a delegated method; an
+exception will be thrown if you try. That is to say, if you define C<foo> in
+your class, you cannot override it with a delegated C<foo>. This is almost never
+something you would want to do, and if it is, you should do it by hand and not
+use Moose.
+
+You cannot override any of the methods found in Moose::Object, or the C<BUILD>
+and C<DEMOLISH> methods. These will not throw an exception, but will silently
+move on to the next method in the list. My reasoning for this is that you would
+almost never want to do this, since it usually breaks your class. As with
+overriding locally defined methods, if you do want to do this, you should do it
+manually, not with Moose.
+
+You do not I<need> to have a reader (or accessor) for the attribute in order
+to delegate to it. Moose will create a means of accessing the value for you,
+however this will be several times B<less> efficient then if you had given
+the attribute a reader (or accessor) to use.
+
+Below is the documentation for each option format:
+
+=over 4
+
+=item C<ARRAY>
+
+This is the most common usage for I<handles>. You basically pass a list of
+method names to be delegated, and Moose will install a delegation method
+for each one.
+
+=item C<HASH>
+
+This is the second most common usage for I<handles>. Instead of a list of
+method names, you pass a HASH ref where each key is the method name you
+want installed locally, and its value is the name of the original method
+in the class being delegated to.
+
+This can be very useful for recursive classes like trees. Here is a
+quick example (soon to be expanded into a Moose::Cookbook recipe):
+
+ package Tree;
+ use Moose;
+
+ has 'node' => (is => 'rw', isa => 'Any');
+
+ has 'children' => (
+ is => 'ro',
+ isa => 'ArrayRef',
+ default => sub { [] }
+ );
+
+ has 'parent' => (
+ is => 'rw',
+ isa => 'Tree',
+ weak_ref => 1,
+ handles => {
+ parent_node => 'node',
+ siblings => 'children',
+ }
+ );
+
+In this example, the Tree package gets C<parent_node> and C<siblings> methods,
+which delegate to the C<node> and C<children> methods (respectively) of the Tree
+instance stored in the C<parent> slot.
+
+=item C<REGEXP>
+
+The regexp option works very similar to the ARRAY option, except that it builds
+the list of methods for you. It starts by collecting all possible methods of the
+class being delegated to, then filters that list using the regexp supplied here.
+
+B<NOTE:> An I<isa> option is required when using the regexp option format. This
+is so that we can determine (at compile time) the method list from the class.
+Without an I<isa> this is just not possible.
+
+=item C<ROLE>
+
+With the role option, you specify the name of a role whose "interface" then
+becomes the list of methods to handle. The "interface" can be defined as; the
+methods of the role and any required methods of the role. It should be noted
+that this does B<not> include any method modifiers or generated attribute
+methods (which is consistent with role composition).
+
+=item C<CODE>
+
+This is the option to use when you really want to do something funky. You should
+only use it if you really know what you are doing, as it involves manual
+metaclass twiddling.
+
+This takes a code reference, which should expect two arguments. The first is the
+attribute meta-object this I<handles> is attached to. The second is the
+metaclass of the class being delegated to. It expects you to return a hash (not
+a HASH ref) of the methods you want mapped.
+
+=back
+
+=item I<metaclass =E<gt> $metaclass_name>
+
+This tells the class to use a custom attribute metaclass for this particular
+attribute. Custom attribute metaclasses are useful for extending the
+capabilities of the I<has> keyword: they are the simplest way to extend the MOP,
+but they are still a fairly advanced topic and too much to cover here, see
+L<Moose::Cookbook::Meta::Recipe1> for more information.
+
+The default behavior here is to just load C<$metaclass_name>; however, we also
+have a way to alias to a shorter name. This will first look to see if
+B<Moose::Meta::Attribute::Custom::$metaclass_name> exists. If it does, Moose
+will then check to see if that has the method C<register_implementation>, which
+should return the actual name of the custom attribute metaclass. If there is no
+C<register_implementation> method, it will fall back to using
+B<Moose::Meta::Attribute::Custom::$metaclass_name> as the metaclass name.
+
+=item I<traits =E<gt> [ @role_names ]>
+
+This tells Moose to take the list of C<@role_names> and apply them to the
+attribute meta-object. This is very similar to the I<metaclass> option, but
+allows you to use more than one extension at a time.
+
+See L<TRAIT NAME RESOLUTION> for details on how a trait name is
+resolved to a class name.
+
+Also see L<Moose::Cookbook::Meta::Recipe3> for a metaclass trait
+example.
+
+=item I<builder> => Str
+
+The value of this key is the name of the method that will be called to
+obtain the value used to initialize the attribute. See the L<builder
+option docs in Class::MOP::Attribute|Class::MOP::Attribute/builder>
+ and/or L<Moose::Cookbook::Basics::Recipe9> for more information.
+
+=item I<default> => SCALAR | CODE
+
+The value of this key is the default value which will initialize the attribute.
+
+NOTE: If the value is a simple scalar (string or number), then it can
+be just passed as is. However, if you wish to initialize it with a
+HASH or ARRAY ref, then you need to wrap that inside a CODE reference.
+See the L<default option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/default> for more
+information.
+
+=item I<clearer> => Str
+
+Creates a method allowing you to clear the value, see the L<clearer option
+docs in Class::MOP::Attribute|Class::MOP::Attribute/clearer> for more
+information.
+
+=item I<predicate> => Str
+
+Creates a method to perform a basic test to see if a value has been set in the
+attribute, see the L<predicate option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/predicate> for more information.
+
+=item I<lazy_build> => (0|1)
+
+Automatically define lazy => 1 as well as builder => "_build_$attr", clearer =>
+"clear_$attr', predicate => 'has_$attr' unless they are already defined.
+
+=item I<initializer> => Str
+
+This may be a method name (referring to a method on the class with
+this attribute) or a CODE ref. The initializer is used to set the
+attribute value on an instance when the attribute is set during
+instance initialization (but not when the value is being assigned
+to). See the L<initializer option docs in
+Class::MOP::Attribute|Class::MOP::Attribute/initializer> for more
+information.
+
+=back
+
+=item B<has +$name =E<gt> %options>
+
+This is variation on the normal attribute creator C<has> which allows you to
+clone and extend an attribute from a superclass or from a role. Here is an
+example of the superclass usage:
+
+ package Foo;
+ use Moose;
+
+ has 'message' => (
+ is => 'rw',
+ isa => 'Str',
+ default => 'Hello, I am a Foo'
+ );
+
+ package My::Foo;
+ use Moose;
+
+ extends 'Foo';
+
+ has '+message' => (default => 'Hello I am My::Foo');
+
+What is happening here is that B<My::Foo> is cloning the C<message> attribute
+from its parent class B<Foo>, retaining the C<is =E<gt> 'rw'> and C<isa =E<gt>
+'Str'> characteristics, but changing the value in C<default>.
+
+Here is another example, but within the context of a role:
+
+ package Foo::Role;
+ use Moose::Role;
+
+ has 'message' => (
+ is => 'rw',
+ isa => 'Str',
+ default => 'Hello, I am a Foo'
+ );
+
+ package My::Foo;
+ use Moose;
+
+ with 'Foo::Role';
+
+ has '+message' => (default => 'Hello I am My::Foo');
+
+In this case, we are basically taking the attribute which the role supplied
+and altering it within the bounds of this feature.
+
+Aside from where the attributes come from (one from superclass, the other
+from a role), this feature works exactly the same. This feature is restricted
+somewhat, so as to try and force at least I<some> sanity into it. You are only
+allowed to change the following attributes:
+
+=over 4
+
+=item I<default>
+
+Change the default value of an attribute.
+
+=item I<coerce>
+
+Change whether the attribute attempts to coerce a value passed to it.
+
+=item I<required>
+
+Change if the attribute is required to have a value.
+
+=item I<documentation>
+
+Change the documentation string associated with the attribute.
+
+=item I<lazy>
+
+Change if the attribute lazily initializes the slot.
+
+=item I<isa>
+
+You I<are> allowed to change the type without restriction.
+
+It is recommended that you use this freedom with caution. We used to
+only allow for extension only if the type was a subtype of the parent's
+type, but we felt that was too restrictive and is better left as a
+policy decision.
+
+=item I<handles>
+
+You are allowed to B<add> a new C<handles> definition, but you are B<not>
+allowed to I<change> one.
+
+=item I<builder>
+
+You are allowed to B<add> a new C<builder> definition, but you are B<not>
+allowed to I<change> one.
+
+=item I<metaclass>
+
+You are allowed to B<add> a new C<metaclass> definition, but you are
+B<not> allowed to I<change> one.
+
+=item I<traits>
+
+You are allowed to B<add> additional traits to the C<traits> definition.
+These traits will be composed into the attribute, but preexisting traits
+B<are not> overridden, or removed.
+
=back
=item B<before $name|@names =E<gt> sub { ... }>
=item B<around $name|@names =E<gt> sub { ... }>
-This three items are syntactic sugar for the before, after and around method
-modifier features that L<Class::MOP> provides. More information on these can
-be found in the L<Class::MOP> documentation for now.
+This three items are syntactic sugar for the before, after, and around method
+modifier features that L<Class::MOP> provides. More information on these may be
+found in the L<Class::MOP::Class documentation|Class::MOP::Class/"Method
+Modifiers"> for now.
=item B<super>
-The keyword C<super> is a noop when called outside of an C<override> method. In
-the context of an C<override> method, it will call the next most appropriate
+The keyword C<super> is a no-op when called outside of an C<override> method. In
+the context of an C<override> method, it will call the next most appropriate
superclass method with the same arguments as the original method.
=item B<override ($name, &sub)>
-An C<override> method, is a way of explictly saying "I am overriding this
-method from my superclass". You can call C<super> within this method, and
-it will work as expected. The same thing I<can> be accomplished with a normal
-method call and the C<SUPER::> pseudo-package, it is really your choice.
+An C<override> method is a way of explicitly saying "I am overriding this
+method from my superclass". You can call C<super> within this method, and
+it will work as expected. The same thing I<can> be accomplished with a normal
+method call and the C<SUPER::> pseudo-package; it is really your choice.
=item B<inner>
-The keyword C<inner>, much like C<super>, is a no-op outside of the context of
-an C<augment> method. You can think of C<inner> as being the inverse of
-C<super>, the details of how C<inner> and C<augment> work is best described in
-the L<Moose::Cookbook>.
+The keyword C<inner>, much like C<super>, is a no-op outside of the context of
+an C<augment> method. You can think of C<inner> as being the inverse of
+C<super>; the details of how C<inner> and C<augment> work is best described in
+the L<Moose::Cookbook::Basics::Recipe6>.
=item B<augment ($name, &sub)>
-An C<augment> method, is a way of explictly saying "I am augmenting this
-method from my superclass". Once again, the details of how C<inner> and
-C<augment> work is best described in the L<Moose::Cookbook>.
+An C<augment> method, is a way of explicitly saying "I am augmenting this
+method from my superclass". Once again, the details of how C<inner> and
+C<augment> work is best described in the L<Moose::Cookbook::Basics::Recipe6>.
=item B<confess>
-This is the C<Carp::confess> function, and exported here beause I use it
-all the time. This feature may change in the future, so you have been warned.
+This is the C<Carp::confess> function, and exported here because I use it
+all the time.
=item B<blessed>
-This is the C<Scalar::Uti::blessed> function, it is exported here beause I
-use it all the time. It is highly recommended that this is used instead of
+This is the C<Scalar::Util::blessed> function, it is exported here because I
+use it all the time. It is highly recommended that this is used instead of
C<ref> anywhere you need to test for an object's class name.
=back
+=head1 METACLASS TRAITS
+
+When you use Moose, you can also specify traits which will be applied
+to your metaclass:
+
+ use Moose -traits => 'My::Trait';
+
+This is very similar to the attribute traits feature. When you do
+this, your class's C<meta> object will have the specified traits
+applied to it. See L<TRAIT NAME RESOLUTION> for more details.
+
+=head2 Trait Name Resolution
+
+By default, when given a trait name, Moose simply tries to load a
+class of the same name. If such a class does not exist, it then looks
+for for a class matching
+B<Moose::Meta::$type::Custom::Trait::$trait_name>. The C<$type>
+variable here will be one of B<Attribute> or B<Class>, depending on
+what the trait is being applied to.
+
+If a class with this long name exists, Moose checks to see if it has
+the method C<register_implementation>. This method is expected to
+return the I<real> class name of the trait. If there is no
+C<register_implementation> method, it will fall back to using
+B<Moose::Meta::$type::Custom::Trait::$trait> as the trait name.
+
+If all this is confusing, take a look at
+L<Moose::Cookbook::Meta::Recipe3>, which demonstrates how to create an
+attribute trait.
+
+=head1 UNIMPORTING FUNCTIONS
+
+=head2 B<unimport>
+
+Moose offers a way to remove the keywords it exports, through the C<unimport>
+method. You simply have to say C<no Moose> at the bottom of your code for this
+to work. Here is an example:
+
+ package Person;
+ use Moose;
+
+ has 'first_name' => (is => 'rw', isa => 'Str');
+ has 'last_name' => (is => 'rw', isa => 'Str');
+
+ sub full_name {
+ my $self = shift;
+ $self->first_name . ' ' . $self->last_name
+ }
+
+ no Moose; # keywords are removed from the Person package
+
+=head1 EXTENDING AND EMBEDDING MOOSE
+
+To learn more about extending Moose, we recommend checking out the
+"Extending" recipes in the L<Moose::Cookbook>, starting with
+L<Moose::Cookbook::Extending::Recipe1>, which provides an overview of
+all the different ways you might extend Moose.
+
+=head2 B<< Moose->init_meta(for_class => $class, base_class => $baseclass, metaclass => $metaclass) >>
+
+The C<init_meta> method sets up the metaclass object for the class
+specified by C<for_class>. This method injects a a C<meta> accessor
+into the class so you can get at this object. It also sets the class's
+superclass to C<base_class>, with L<Moose::Object> as the default.
+
+You can specify an alternate metaclass with the C<metaclass> option.
+
+For more detail on this topic, see L<Moose::Cookbook::Extending::Recipe2>.
+
+This method used to be documented as a function which accepted
+positional parameters. This calling style will still work for
+backwards compatibility, but is deprecated.
+
+=head2 B<import>
+
+Moose's C<import> method supports the L<Sub::Exporter> form of C<{into =E<gt> $pkg}>
+and C<{into_level =E<gt> 1}>.
+
+B<NOTE>: Doing this is more or less deprecated. Use L<Moose::Exporter>
+instead, which lets you stack multiple C<Moose.pm>-alike modules
+sanely. It handles getting the exported functions into the right place
+for you.
+
+=head2 B<throw_error>
+
+An alias for C<confess>, used by internally by Moose.
+
+=head1 METACLASS COMPATIBILITY AND MOOSE
+
+Metaclass compatibility is a thorny subject. You should start by
+reading the "About Metaclass compatibility" section in the
+C<Class::MOP> docs.
+
+Moose will attempt to resolve a few cases of metaclass incompatibility
+when you set the superclasses for a class, unlike C<Class::MOP>, which
+simply dies if the metaclasses are incompatible.
+
+In actuality, Moose fixes incompatibility for I<all> of a class's
+metaclasses, not just the class metaclass. That includes the instance
+metaclass, attribute metaclass, as well as its constructor class and
+destructor class. However, for simplicity this discussion will just
+refer to "metaclass", meaning the class metaclass, most of the time.
+
+Moose has two algorithms for fixing metaclass incompatibility.
+
+The first algorithm is very simple. If all the metaclass for the
+parent is a I<subclass> of the child's metaclass, then we simply
+replace the child's metaclass with the parent's.
+
+The second algorithm is more complicated. It tries to determine if the
+metaclasses only "differ by roles". This means that the parent and
+child's metaclass share a common ancestor in their respective
+hierarchies, and that the subclasses under the common ancestor are
+only different because of role applications. This case is actually
+fairly common when you mix and match various C<MooseX::*> modules,
+many of which apply roles to the metaclass.
+
+If the parent and child do differ by roles, Moose replaces the
+metaclass in the child with a newly created metaclass. This metaclass
+is a subclass of the parent's metaclass, does all of the roles that
+the child's metaclass did before being replaced. Effectively, this
+means the new metaclass does all of the roles done by both the
+parent's and child's original metaclasses.
+
+Ultimately, this is all transparent to you except in the case of an
+unresolvable conflict.
+
+=head2 The MooseX:: namespace
+
+Generally if you're writing an extension I<for> Moose itself you'll want
+to put your extension in the C<MooseX::> namespace. This namespace is
+specifically for extensions that make Moose better or different in some
+fundamental way. It is traditionally B<not> for a package that just happens
+to use Moose. This namespace follows from the examples of the C<LWPx::>
+and C<DBIx::> namespaces that perform the same function for C<LWP> and C<DBI>
+respectively.
+
=head1 CAVEATS
=over 4
=item *
-It should be noted that C<super> and C<inner> can B<not> be used in the same
-method. However, they can be combined together with the same class hierarchy,
-see F<t/014_override_augment_inner_super.t> for an example.
+It should be noted that C<super> and C<inner> B<cannot> be used in the same
+method. However, they may be combined within the same class hierarchy; see
+F<t/014_override_augment_inner_super.t> for an example.
-The reason that this is so is because C<super> is only valid within a method
-with the C<override> modifier, and C<inner> will never be valid within an
-C<override> method. In fact, C<augment> will skip over any C<override> methods
-when searching for it's appropriate C<inner>.
+The reason for this is that C<super> is only valid within a method
+with the C<override> modifier, and C<inner> will never be valid within an
+C<override> method. In fact, C<augment> will skip over any C<override> methods
+when searching for its appropriate C<inner>.
-This might seem like a restriction, but I am of the opinion that keeping these
-two features seperate (but interoperable) actually makes them easy to use since
-their behavior is then easier to predict. Time will tell if I am right or not.
+This might seem like a restriction, but I am of the opinion that keeping these
+two features separate (yet interoperable) actually makes them easy to use, since
+their behavior is then easier to predict. Time will tell whether I am right or
+not (UPDATE: so far so good).
=back
+=head1 GETTING HELP
+
+We offer both a mailing list and a very active IRC channel.
+
+The mailing list is L<moose@perl.org>. You must be subscribed to send
+a message. To subscribe, send an empty message to
+L<moose-subscribe@perl.org>
+
+You can also visit us at L<#moose on
+irc.perl.org|irc://irc.perl.org/#moose>. This channel is quite active,
+and questions at all levels (on Moose-related topics ;) are welcome.
+
=head1 ACKNOWLEDGEMENTS
=over 4
=item I blame Audrey Tang for then encouraging my meta-model habit in #perl6.
-=item Without Yuval "nothingmuch" Kogman this module would not be possible,
+=item Without Yuval "nothingmuch" Kogman this module would not be possible,
and it certainly wouldn't have this name ;P
-=item The basis of the TypeContraints module was Rob Kinyon's idea
+=item The basis of the TypeContraints module was Rob Kinyon's idea
originally, I just ran with it.
-=item Thanks to mst & chansen and the whole #moose poose for all the
-ideas/feature-requests/encouragement
+=item Thanks to mst & chansen and the whole #moose posse for all the
+early ideas/feature-requests/encouragement/bug-finding.
+
+=item Thanks to David "Theory" Wheeler for meta-discussions and spelling fixes.
=back
=over 4
-=item L<Class::MOP> documentation
+=item L<http://www.iinteractive.com/moose>
+
+This is the official web home of Moose, it contains links to our public SVN repository
+as well as links to a number of talks and articles on Moose and Moose related
+technologies.
+
+=item The Moose is flying, a tutorial by Randal Schwartz
+
+Part 1 - L<http://www.stonehenge.com/merlyn/LinuxMag/col94.html>
+
+Part 2 - L<http://www.stonehenge.com/merlyn/LinuxMag/col95.html>
+
+=item Several Moose extension modules in the C<MooseX::> namespace.
+
+See L<http://search.cpan.org/search?query=MooseX::> for extensions.
+
+=item Moose stats on ohloh.net - L<http://www.ohloh.net/projects/moose>
+
+=back
+
+=head2 Books
+
+=over 4
+
+=item The Art of the MetaObject Protocol
-=item The #moose channel on irc.perl.org
+I mention this in the L<Class::MOP> docs too, this book was critical in
+the development of both modules and is highly recommended.
-=item L<http://forum2.org/moose/>
+=back
+
+=head2 Papers
+
+=over 4
=item L<http://www.cs.utah.edu/plt/publications/oopsla04-gff.pdf>
-This paper (suggested by lbr on #moose) was what lead to the implementation
-of the C<super>/C<overrride> and C<inner>/C<augment> features. If you really
-want to understand this feature, I suggest you read this.
+This paper (suggested by lbr on #moose) was what lead to the implementation
+of the C<super>/C<override> and C<inner>/C<augment> features. If you really
+want to understand them, I suggest you read this.
=back
=head1 BUGS
-All complex software has bugs lurking in it, and this module is no
+All complex software has bugs lurking in it, and this module is no
exception. If you find a bug please either email me, or add the bug
to cpan-RT.
+=head1 FEATURE REQUESTS
+
+We are very strict about what features we add to the Moose core, especially
+the user-visible features. Instead we have made sure that the underlying
+meta-system of Moose is as extensible as possible so that you can add your
+own features easily. That said, occasionally there is a feature needed in the
+meta-system to support your planned extension, in which case you should
+either email the mailing list or join us on irc at #moose to discuss. The
+L<Moose::Manual::Contributing> has more detail about how and when you can
+contribute.
+
=head1 AUTHOR
-Stevan Little E<lt>stevan@iinteractive.comE<gt>
+Moose is an open project, there are at this point dozens of people who have
+contributed, and can contribute. If you have added anything to the Moose
+project you have a commit bit on this file and can add your name to the list.
+
+=head2 CABAL
+
+However there are only a few people with the rights to release a new version
+of Moose. The Moose Cabal are the people to go to with questions regarding
+the wider purview of Moose, and help out maintaining not just the code
+but the community as well.
+
+Stevan (stevan) Little E<lt>stevan@iinteractive.comE<gt>
+
+Yuval (nothingmuch) Kogman
+
+Shawn (sartak) Moore
+
+Dave (autarch) Rolsky E<lt>autarch@urth.orgE<gt>
+
+=head2 OTHER CONTRIBUTORS
+
+Aankhen
+
+Adam (Alias) Kennedy
+
+Anders (Debolaz) Nor Berle
+
+Nathan (kolibrie) Gray
+
+Christian (chansen) Hansen
+
+Hans Dieter (confound) Pearcey
+
+Eric (ewilhelm) Wilhelm
+
+Guillermo (groditi) Roditi
+
+Jess (castaway) Robinson
+
+Matt (mst) Trout
+
+Robert (phaylon) Sedlacek
+
+Robert (rlb3) Boone
+
+Scott (konobi) McWhirter
+
+Shlomi (rindolf) Fish
+
+Chris (perigrin) Prather
+
+Wallace (wreis) Reis
+
+Jonathan (jrockway) Rockway
+
+Piotr (dexter) Roszatycki
+
+Sam (mugwump) Vilain
+
+Cory (gphat) Watson
+
+... and many other #moose folks
=head1 COPYRIGHT AND LICENSE
-Copyright 2006 by Infinity Interactive, Inc.
+Copyright 2006-2009 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
This library is free software; you can redistribute it and/or modify
-it under the same terms as Perl itself.
+it under the same terms as Perl itself.
=cut