Moose-2.1405HEADMoose-2.1405master

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diff --git a/lib/Class/MOP/Attribute.pm b/lib/Class/MOP/Attribute.pm
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+++ b/lib/Class/MOP/Attribute.pm
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+package Class::MOP::Attribute;
+our $VERSION = '2.1405';
+
+use strict;
+use warnings;
+
+use Class::MOP::Method::Accessor;
+
+use Carp         'confess';
+use Scalar::Util 'blessed', 'weaken';
+use Try::Tiny;
+
+use parent 'Class::MOP::Object', 'Class::MOP::Mixin::AttributeCore';
+
+# NOTE: (meta-circularity)
+# This method will be replaced in the
+# boostrap section of Class::MOP, by
+# a new version which uses the
+# &Class::MOP::Class::construct_instance
+# method to build an attribute meta-object
+# which itself is described with attribute
+# meta-objects.
+#     - Ain't meta-circularity grand? :)
+sub new {
+    my ( $class, @args ) = @_;
+
+    unshift @args, "name" if @args % 2 == 1;
+    my %options = @args;
+
+    my $name = $options{name};
+
+    (defined $name)
+        || $class->_throw_exception( MOPAttributeNewNeedsAttributeName => class  => $class,
+                                                                 params => \%options
+                          );
+
+    $options{init_arg} = $name
+        if not exists $options{init_arg};
+    if(exists $options{builder}){
+        $class->_throw_exception( BuilderMustBeAMethodName => class  => $class,
+                                                     params => \%options
+                       )
+            if ref $options{builder} || !(defined $options{builder});
+        $class->_throw_exception( BothBuilderAndDefaultAreNotAllowed => class  => $class,
+                                                               params => \%options
+                       )
+            if exists $options{default};
+    } else {
+        ($class->is_default_a_coderef(\%options))
+            || $class->_throw_exception( ReferencesAreNotAllowedAsDefault => class          => $class,
+                                                                    params         => \%options,
+                                                                    attribute_name => $options{name}
+                              )
+                if exists $options{default} && ref $options{default};
+    }
+
+    if( $options{required} and not( defined($options{builder}) || defined($options{init_arg}) || exists $options{default} ) ) {
+        $class->_throw_exception( RequiredAttributeLacksInitialization => class  => $class,
+                                                                 params => \%options
+                       );
+    }
+
+    $class->_new(\%options);
+}
+
+sub _new {
+    my $class = shift;
+
+    return Class::MOP::Class->initialize($class)->new_object(@_)
+        if $class ne __PACKAGE__;
+
+    my $options = @_ == 1 ? $_[0] : {@_};
+
+    bless {
+        'name'               => $options->{name},
+        'accessor'           => $options->{accessor},
+        'reader'             => $options->{reader},
+        'writer'             => $options->{writer},
+        'predicate'          => $options->{predicate},
+        'clearer'            => $options->{clearer},
+        'builder'            => $options->{builder},
+        'init_arg'           => $options->{init_arg},
+        exists $options->{default}
+            ? ('default'     => $options->{default})
+            : (),
+        'initializer'        => $options->{initializer},
+        'definition_context' => $options->{definition_context},
+        # keep a weakened link to the
+        # class we are associated with
+        'associated_class' => undef,
+        # and a list of the methods
+        # associated with this attr
+        'associated_methods' => [],
+        # this let's us keep track of
+        # our order inside the associated
+        # class
+        'insertion_order'    => undef,
+    }, $class;
+}
+
+# NOTE:
+# this is a primitive (and kludgy) clone operation
+# for now, it will be replaced in the Class::MOP
+# bootstrap with a proper one, however we know
+# that this one will work fine for now.
+sub clone {
+    my $self    = shift;
+    my %options = @_;
+    (blessed($self))
+        || confess "Can only clone an instance";
+    # this implementation is overwritten by the bootstrap process,
+    # so this exception will never trigger. If it ever does occur,
+    # it indicates a gigantic problem with the most internal parts
+    # of Moose, so we wouldn't want a Moose-based exception object anyway
+
+    return bless { %{$self}, %options } => ref($self);
+}
+
+sub initialize_instance_slot {
+    my ($self, $meta_instance, $instance, $params) = @_;
+    my $init_arg = $self->{'init_arg'};
+
+    # try to fetch the init arg from the %params ...
+
+    # if nothing was in the %params, we can use the
+    # attribute's default value (if it has one)
+    if(defined $init_arg and exists $params->{$init_arg}){
+        $self->_set_initial_slot_value(
+            $meta_instance,
+            $instance,
+            $params->{$init_arg},
+        );
+    }
+    elsif (exists $self->{'default'}) {
+        $self->_set_initial_slot_value(
+            $meta_instance,
+            $instance,
+            $self->default($instance),
+        );
+    }
+    elsif (defined( my $builder = $self->{'builder'})) {
+        if ($builder = $instance->can($builder)) {
+            $self->_set_initial_slot_value(
+                $meta_instance,
+                $instance,
+                $instance->$builder,
+            );
+        }
+        else {
+            $self->_throw_exception( BuilderMethodNotSupportedForAttribute => attribute => $self,
+                                                                      instance  => $instance
+                           );
+        }
+    }
+}
+
+sub _set_initial_slot_value {
+    my ($self, $meta_instance, $instance, $value) = @_;
+
+    my $slot_name = $self->name;
+
+    return $meta_instance->set_slot_value($instance, $slot_name, $value)
+        unless $self->has_initializer;
+
+    my $callback = $self->_make_initializer_writer_callback(
+        $meta_instance, $instance, $slot_name
+    );
+
+    my $initializer = $self->initializer;
+
+    # most things will just want to set a value, so make it first arg
+    $instance->$initializer($value, $callback, $self);
+}
+
+sub _make_initializer_writer_callback {
+    my $self = shift;
+    my ($meta_instance, $instance, $slot_name) = @_;
+
+    return sub {
+        $meta_instance->set_slot_value($instance, $slot_name, $_[0]);
+    };
+}
+
+sub get_read_method  {
+    my $self   = shift;
+    my $reader = $self->reader || $self->accessor;
+    # normal case ...
+    return $reader unless ref $reader;
+    # the HASH ref case
+    my ($name) = %$reader;
+    return $name;
+}
+
+sub get_write_method {
+    my $self   = shift;
+    my $writer = $self->writer || $self->accessor;
+    # normal case ...
+    return $writer unless ref $writer;
+    # the HASH ref case
+    my ($name) = %$writer;
+    return $name;
+}
+
+sub get_read_method_ref {
+    my $self = shift;
+    if ((my $reader = $self->get_read_method) && $self->associated_class) {
+        return $self->associated_class->get_method($reader);
+    }
+    else {
+        my $code = sub { $self->get_value(@_) };
+        if (my $class = $self->associated_class) {
+            return $class->method_metaclass->wrap(
+                $code,
+                package_name => $class->name,
+                name         => '__ANON__'
+            );
+        }
+        else {
+            return $code;
+        }
+    }
+}
+
+sub get_write_method_ref {
+    my $self = shift;
+    if ((my $writer = $self->get_write_method) && $self->associated_class) {
+        return $self->associated_class->get_method($writer);
+    }
+    else {
+        my $code = sub { $self->set_value(@_) };
+        if (my $class = $self->associated_class) {
+            return $class->method_metaclass->wrap(
+                $code,
+                package_name => $class->name,
+                name         => '__ANON__'
+            );
+        }
+        else {
+            return $code;
+        }
+    }
+}
+
+# slots
+
+sub slots { (shift)->name }
+
+# class association
+
+sub attach_to_class {
+    my ($self, $class) = @_;
+    (blessed($class) && $class->isa('Class::MOP::Class'))
+        || $self->_throw_exception( AttachToClassNeedsAClassMOPClassInstanceOrASubclass => attribute => $self,
+                                                                                   class     => $class
+                          );
+    weaken($self->{'associated_class'} = $class);
+}
+
+sub detach_from_class {
+    my $self = shift;
+    $self->{'associated_class'} = undef;
+}
+
+# method association
+
+sub associate_method {
+    my ($self, $method) = @_;
+    push @{$self->{'associated_methods'}} => $method;
+}
+
+## Slot management
+
+sub set_initial_value {
+    my ($self, $instance, $value) = @_;
+    $self->_set_initial_slot_value(
+        Class::MOP::Class->initialize(ref($instance))->get_meta_instance,
+        $instance,
+        $value
+    );
+}
+
+sub set_value { shift->set_raw_value(@_) }
+
+sub set_raw_value {
+    my $self = shift;
+    my ($instance, $value) = @_;
+
+    my $mi = Class::MOP::Class->initialize(ref($instance))->get_meta_instance;
+    return $mi->set_slot_value($instance, $self->name, $value);
+}
+
+sub _inline_set_value {
+    my $self = shift;
+    return $self->_inline_instance_set(@_) . ';';
+}
+
+sub _inline_instance_set {
+    my $self = shift;
+    my ($instance, $value) = @_;
+
+    my $mi = $self->associated_class->get_meta_instance;
+    return $mi->inline_set_slot_value($instance, $self->name, $value);
+}
+
+sub get_value { shift->get_raw_value(@_) }
+
+sub get_raw_value {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = Class::MOP::Class->initialize(ref($instance))->get_meta_instance;
+    return $mi->get_slot_value($instance, $self->name);
+}
+
+sub _inline_get_value {
+    my $self = shift;
+    return $self->_inline_instance_get(@_) . ';';
+}
+
+sub _inline_instance_get {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = $self->associated_class->get_meta_instance;
+    return $mi->inline_get_slot_value($instance, $self->name);
+}
+
+sub has_value {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = Class::MOP::Class->initialize(ref($instance))->get_meta_instance;
+    return $mi->is_slot_initialized($instance, $self->name);
+}
+
+sub _inline_has_value {
+    my $self = shift;
+    return $self->_inline_instance_has(@_) . ';';
+}
+
+sub _inline_instance_has {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = $self->associated_class->get_meta_instance;
+    return $mi->inline_is_slot_initialized($instance, $self->name);
+}
+
+sub clear_value {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = Class::MOP::Class->initialize(ref($instance))->get_meta_instance;
+    return $mi->deinitialize_slot($instance, $self->name);
+}
+
+sub _inline_clear_value {
+    my $self = shift;
+    return $self->_inline_instance_clear(@_) . ';';
+}
+
+sub _inline_instance_clear {
+    my $self = shift;
+    my ($instance) = @_;
+
+    my $mi = $self->associated_class->get_meta_instance;
+    return $mi->inline_deinitialize_slot($instance, $self->name);
+}
+
+## load em up ...
+
+sub accessor_metaclass { 'Class::MOP::Method::Accessor' }
+
+sub _process_accessors {
+    my ($self, $type, $accessor, $generate_as_inline_methods) = @_;
+
+    my $method_ctx = { %{ $self->definition_context || {} } };
+
+    if (ref($accessor)) {
+        (ref($accessor) eq 'HASH')
+            || $self->_throw_exception( BadOptionFormat => attribute    => $self,
+                                                   option_value => $accessor,
+                                                   option_name  => $type
+                              );
+
+        my ($name, $method) = %{$accessor};
+
+        $method_ctx->{description} = $self->_accessor_description($name, $type);
+
+        $method = $self->accessor_metaclass->wrap(
+            $method,
+            attribute    => $self,
+            package_name => $self->associated_class->name,
+            name         => $name,
+            associated_metaclass => $self->associated_class,
+            definition_context => $method_ctx,
+        );
+        $self->associate_method($method);
+        return ($name, $method);
+    }
+    else {
+        my $inline_me = ($generate_as_inline_methods && $self->associated_class->instance_metaclass->is_inlinable);
+        my $method;
+        try {
+            $method_ctx->{description} = $self->_accessor_description($accessor, $type);
+
+            $method = $self->accessor_metaclass->new(
+                attribute     => $self,
+                is_inline     => $inline_me,
+                accessor_type => $type,
+                package_name  => $self->associated_class->name,
+                name          => $accessor,
+                associated_metaclass => $self->associated_class,
+                definition_context => $method_ctx,
+            );
+        }
+        catch {
+            $self->_throw_exception( CouldNotCreateMethod => attribute    => $self,
+                                                     option_value => $accessor,
+                                                     option_name  => $type,
+                                                     error        => $_
+                           );
+        };
+        $self->associate_method($method);
+        return ($accessor, $method);
+    }
+}
+
+sub _accessor_description {
+    my $self = shift;
+    my ($name, $type) = @_;
+
+    my $desc = "$type " . $self->associated_class->name . "::$name";
+    if ( $name ne $self->name ) {
+        $desc .= " of attribute " . $self->name;
+    }
+
+    return $desc;
+}
+
+sub install_accessors {
+    my $self   = shift;
+    my $inline = shift;
+    my $class  = $self->associated_class;
+
+    $class->add_method(
+        $self->_process_accessors('accessor' => $self->accessor(), $inline)
+    ) if $self->has_accessor();
+
+    $class->add_method(
+        $self->_process_accessors('reader' => $self->reader(), $inline)
+    ) if $self->has_reader();
+
+    $class->add_method(
+        $self->_process_accessors('writer' => $self->writer(), $inline)
+    ) if $self->has_writer();
+
+    $class->add_method(
+        $self->_process_accessors('predicate' => $self->predicate(), $inline)
+    ) if $self->has_predicate();
+
+    $class->add_method(
+        $self->_process_accessors('clearer' => $self->clearer(), $inline)
+    ) if $self->has_clearer();
+
+    return;
+}
+
+{
+    my $_remove_accessor = sub {
+        my ($accessor, $class) = @_;
+        if (ref($accessor) && ref($accessor) eq 'HASH') {
+            ($accessor) = keys %{$accessor};
+        }
+        my $method = $class->get_method($accessor);
+        $class->remove_method($accessor)
+            if (ref($method) && $method->isa('Class::MOP::Method::Accessor'));
+    };
+
+    sub remove_accessors {
+        my $self = shift;
+        # TODO:
+        # we really need to make sure to remove from the
+        # associates methods here as well. But this is
+        # such a slimly used method, I am not worried
+        # about it right now.
+        $_remove_accessor->($self->accessor(),  $self->associated_class()) if $self->has_accessor();
+        $_remove_accessor->($self->reader(),    $self->associated_class()) if $self->has_reader();
+        $_remove_accessor->($self->writer(),    $self->associated_class()) if $self->has_writer();
+        $_remove_accessor->($self->predicate(), $self->associated_class()) if $self->has_predicate();
+        $_remove_accessor->($self->clearer(),   $self->associated_class()) if $self->has_clearer();
+        return;
+    }
+
+}
+
+1;
+
+# ABSTRACT: Attribute Meta Object
+
+__END__
+
+=pod
+
+=encoding UTF-8
+
+=head1 NAME
+
+Class::MOP::Attribute - Attribute Meta Object
+
+=head1 VERSION
+
+version 2.1405
+
+=head1 SYNOPSIS
+
+  Class::MOP::Attribute->new(
+      foo => (
+          accessor  => 'foo',           # dual purpose get/set accessor
+          predicate => 'has_foo',       # predicate check for defined-ness
+          init_arg  => '-foo',          # class->new will look for a -foo key
+          default   => 'BAR IS BAZ!'    # if no -foo key is provided, use this
+      )
+  );
+
+  Class::MOP::Attribute->new(
+      bar => (
+          reader    => 'bar',           # getter
+          writer    => 'set_bar',       # setter
+          predicate => 'has_bar',       # predicate check for defined-ness
+          init_arg  => ':bar',          # class->new will look for a :bar key
+                                        # no default value means it is undef
+      )
+  );
+
+=head1 DESCRIPTION
+
+The Attribute Protocol is almost entirely an invention of
+C<Class::MOP>. Perl 5 does not have a consistent notion of
+attributes. There are so many ways in which this is done, and very few
+(if any) are easily discoverable by this module.
+
+With that said, this module attempts to inject some order into this
+chaos, by introducing a consistent API which can be used to create
+object attributes.
+
+=head1 METHODS
+
+=head2 Creation
+
+=over 4
+
+=item B<< Class::MOP::Attribute->new($name, ?%options) >>
+
+An attribute must (at the very least), have a C<$name>. All other
+C<%options> are added as key-value pairs.
+
+=over 8
+
+=item * init_arg
+
+This is a string value representing the expected key in an
+initialization hash. For instance, if we have an C<init_arg> value of
+C<-foo>, then the following code will Just Work.
+
+  MyClass->meta->new_object( -foo => 'Hello There' );
+
+If an init_arg is not assigned, it will automatically use the
+attribute's name. If C<init_arg> is explicitly set to C<undef>, the
+attribute cannot be specified during initialization.
+
+=item * builder
+
+This provides the name of a method that will be called to initialize
+the attribute. This method will be called on the object after it is
+constructed. It is expected to return a valid value for the attribute.
+
+=item * default
+
+This can be used to provide an explicit default for initializing the
+attribute. If the default you provide is a subroutine reference, then
+this reference will be called I<as a method> on the object.
+
+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 subroutine
+reference:
+
+  Class::MOP::Attribute->new(
+      'foo' => (
+          default => sub { [] },
+      )
+  );
+
+  # or ...
+
+  Class::MOP::Attribute->new(
+      'foo' => (
+          default => sub { {} },
+      )
+  );
+
+If you wish to initialize an attribute with a subroutine reference
+itself, then you need to wrap that in a subroutine as well:
+
+  Class::MOP::Attribute->new(
+      'foo' => (
+          default => sub {
+              sub { print "Hello World" }
+          },
+      )
+  );
+
+And lastly, if the value of your attribute is dependent upon some
+other aspect of the instance structure, then you can take advantage of
+the fact that when the C<default> value is called as a method:
+
+  Class::MOP::Attribute->new(
+      'object_identity' => (
+          default => sub { Scalar::Util::refaddr( $_[0] ) },
+      )
+  );
+
+Note that there is no guarantee that attributes are initialized in any
+particular order, so you cannot rely on the value of some other
+attribute when generating the default.
+
+=item * initializer
+
+This option can be either a method name or a subroutine
+reference. This method will be called when setting the attribute's
+value in the constructor. Unlike C<default> and C<builder>, the
+initializer is only called when a value is provided to the
+constructor. The initializer allows you to munge this value during
+object construction.
+
+The initializer is called as a method with three arguments. The first
+is the value that was passed to the constructor. The second is a
+subroutine reference that can be called to actually set the
+attribute's value, and the last is the associated
+C<Class::MOP::Attribute> object.
+
+This contrived example shows an initializer that sets the attribute to
+twice the given value.
+
+  Class::MOP::Attribute->new(
+      'doubled' => (
+          initializer => sub {
+              my ( $self, $value, $set, $attr ) = @_;
+              $set->( $value * 2 );
+          },
+      )
+  );
+
+Since an initializer can be a method name, you can easily make
+attribute initialization use the writer:
+
+  Class::MOP::Attribute->new(
+      'some_attr' => (
+          writer      => 'some_attr',
+          initializer => 'some_attr',
+      )
+  );
+
+Your writer (actually, a wrapper around the writer, using
+L<method modifications|Moose::Manual::MethodModifiers>) will need to examine
+C<@_> and determine under which
+context it is being called:
+
+  around 'some_attr' => sub {
+      my $orig = shift;
+      my $self = shift;
+      # $value is not defined if being called as a reader
+      # $setter and $attr are only defined if being called as an initializer
+      my ($value, $setter, $attr) = @_;
+
+      # the reader behaves normally
+      return $self->$orig if not @_;
+
+      # mutate $value as desired
+      # $value = <something($value);
+
+      # if called as an initializer, set the value and we're done
+      return $setter->($row) if $setter;
+
+      # otherwise, call the real writer with the new value
+      $self->$orig($row);
+  };
+
+=back
+
+The C<accessor>, C<reader>, C<writer>, C<predicate> and C<clearer>
+options all accept the same parameters. You can provide the name of
+the method, in which case an appropriate default method will be
+generated for you. Or instead you can also provide hash reference
+containing exactly one key (the method name) and one value. The value
+should be a subroutine reference, which will be installed as the
+method itself.
+
+=over 8
+
+=item * accessor
+
+An C<accessor> is a standard Perl-style read/write accessor. It will
+return the value of the attribute, and if a value is passed as an
+argument, it will assign that value to the attribute.
+
+Note that C<undef> is a legitimate value, so this will work:
+
+  $object->set_something(undef);
+
+=item * reader
+
+This is a basic read-only accessor. It returns the value of the
+attribute.
+
+=item * writer
+
+This is a basic write accessor, it accepts a single argument, and
+assigns that value to the attribute.
+
+Note that C<undef> is a legitimate value, so this will work:
+
+  $object->set_something(undef);
+
+=item * predicate
+
+The predicate method returns a boolean indicating whether or not the
+attribute has been explicitly set.
+
+Note that the predicate returns true even if the attribute was set to
+a false value (C<0> or C<undef>).
+
+=item * clearer
+
+This method will uninitialize the attribute. After an attribute is
+cleared, its C<predicate> will return false.
+
+=item * definition_context
+
+Mostly, this exists as a hook for the benefit of Moose.
+
+This option should be a hash reference containing several keys which
+will be used when inlining the attribute's accessors. The keys should
+include C<line>, the line number where the attribute was created, and
+either C<file> or C<description>.
+
+This information will ultimately be used when eval'ing inlined
+accessor code so that error messages report a useful line and file
+name.
+
+=back
+
+=item B<< $attr->clone(%options) >>
+
+This clones the attribute. Any options you provide will override the
+settings of the original attribute. You can change the name of the new
+attribute by passing a C<name> key in C<%options>.
+
+=back
+
+=head2 Informational
+
+These are all basic read-only accessors for the values passed into
+the constructor.
+
+=over 4
+
+=item B<< $attr->name >>
+
+Returns the attribute's name.
+
+=item B<< $attr->accessor >>
+
+=item B<< $attr->reader >>
+
+=item B<< $attr->writer >>
+
+=item B<< $attr->predicate >>
+
+=item B<< $attr->clearer >>
+
+The C<accessor>, C<reader>, C<writer>, C<predicate>, and C<clearer>
+methods all return exactly what was passed to the constructor, so it
+can be either a string containing a method name, or a hash reference.
+
+=item B<< $attr->initializer >>
+
+Returns the initializer as passed to the constructor, so this may be
+either a method name or a subroutine reference.
+
+=item B<< $attr->init_arg >>
+
+=item B<< $attr->is_default_a_coderef >>
+
+=item B<< $attr->builder >>
+
+=item B<< $attr->default($instance) >>
+
+The C<$instance> argument is optional. If you don't pass it, the
+return value for this method is exactly what was passed to the
+constructor, either a simple scalar or a subroutine reference.
+
+If you I<do> pass an C<$instance> and the default is a subroutine
+reference, then the reference is called as a method on the
+C<$instance> and the generated value is returned.
+
+=item B<< $attr->slots >>
+
+Return a list of slots required by the attribute. This is usually just
+one, the name of the attribute.
+
+A slot is the name of the hash key used to store the attribute in an
+object instance.
+
+=item B<< $attr->get_read_method >>
+
+=item B<< $attr->get_write_method >>
+
+Returns the name of a method suitable for reading or writing the value
+of the attribute in the associated class.
+
+If an attribute is read- or write-only, then these methods can return
+C<undef> as appropriate.
+
+=item B<< $attr->has_read_method >>
+
+=item B<< $attr->has_write_method >>
+
+This returns a boolean indicating whether the attribute has a I<named>
+read or write method.
+
+=item B<< $attr->get_read_method_ref >>
+
+=item B<< $attr->get_write_method_ref >>
+
+Returns the subroutine reference of a method suitable for reading or
+writing the attribute's value in the associated class. These methods
+always return a subroutine reference, regardless of whether or not the
+attribute is read- or write-only.
+
+=item B<< $attr->insertion_order >>
+
+If this attribute has been inserted into a class, this returns a zero
+based index regarding the order of insertion.
+
+=back
+
+=head2 Informational predicates
+
+These are all basic predicate methods for the values passed into C<new>.
+
+=over 4
+
+=item B<< $attr->has_accessor >>
+
+=item B<< $attr->has_reader >>
+
+=item B<< $attr->has_writer >>
+
+=item B<< $attr->has_predicate >>
+
+=item B<< $attr->has_clearer >>
+
+=item B<< $attr->has_initializer >>
+
+=item B<< $attr->has_init_arg >>
+
+This will be I<false> if the C<init_arg> was set to C<undef>.
+
+=item B<< $attr->has_default >>
+
+This will be I<false> if the C<default> was set to C<undef>, since
+C<undef> is the default C<default> anyway.
+
+=item B<< $attr->has_builder >>
+
+=item B<< $attr->has_insertion_order >>
+
+This will be I<false> if this attribute has not be inserted into a class
+
+=back
+
+=head2 Value management
+
+These methods are basically "back doors" to the instance, and can be
+used to bypass the regular accessors, but still stay within the MOP.
+
+These methods are not for general use, and should only be used if you
+really know what you are doing.
+
+=over 4
+
+=item B<< $attr->initialize_instance_slot($meta_instance, $instance, $params) >>
+
+This method is used internally to initialize the attribute's slot in
+the object C<$instance>.
+
+The C<$params> is a hash reference of the values passed to the object
+constructor.
+
+It's unlikely that you'll need to call this method yourself.
+
+=item B<< $attr->set_value($instance, $value) >>
+
+Sets the value without going through the accessor. Note that this
+works even with read-only attributes.
+
+=item B<< $attr->set_raw_value($instance, $value) >>
+
+Sets the value with no side effects such as a trigger.
+
+This doesn't actually apply to Class::MOP attributes, only to subclasses.
+
+=item B<< $attr->set_initial_value($instance, $value) >>
+
+Sets the value without going through the accessor. This method is only
+called when the instance is first being initialized.
+
+=item B<< $attr->get_value($instance) >>
+
+Returns the value without going through the accessor. Note that this
+works even with write-only accessors.
+
+=item B<< $attr->get_raw_value($instance) >>
+
+Returns the value without any side effects such as lazy attributes.
+
+Doesn't actually apply to Class::MOP attributes, only to subclasses.
+
+=item B<< $attr->has_value($instance) >>
+
+Return a boolean indicating whether the attribute has been set in
+C<$instance>. This how the default C<predicate> method works.
+
+=item B<< $attr->clear_value($instance) >>
+
+This will clear the attribute's value in C<$instance>. This is what
+the default C<clearer> calls.
+
+Note that this works even if the attribute does not have any
+associated read, write or clear methods.
+
+=back
+
+=head2 Class association
+
+These methods allow you to manage the attributes association with
+the class that contains it. These methods should not be used
+lightly, nor are they very magical, they are mostly used internally
+and by metaclass instances.
+
+=over 4
+
+=item B<< $attr->associated_class >>
+
+This returns the L<Class::MOP::Class> with which this attribute is
+associated, if any.
+
+=item B<< $attr->attach_to_class($metaclass) >>
+
+This method stores a weakened reference to the C<$metaclass> object
+internally.
+
+This method does not remove the attribute from its old class,
+nor does it create any accessors in the new class.
+
+It is probably best to use the L<Class::MOP::Class> C<add_attribute>
+method instead.
+
+=item B<< $attr->detach_from_class >>
+
+This method removes the associate metaclass object from the attribute
+it has one.
+
+This method does not remove the attribute itself from the class, or
+remove its accessors.
+
+It is probably best to use the L<Class::MOP::Class>
+C<remove_attribute> method instead.
+
+=back
+
+=head2 Attribute Accessor generation
+
+=over 4
+
+=item B<< $attr->accessor_metaclass >>
+
+Accessor methods are generated using an accessor metaclass. By
+default, this is L<Class::MOP::Method::Accessor>. This method returns
+the name of the accessor metaclass that this attribute uses.
+
+=item B<< $attr->associate_method($method) >>
+
+This associates a L<Class::MOP::Method> object with the
+attribute. Typically, this is called internally when an attribute
+generates its accessors.
+
+=item B<< $attr->associated_methods >>
+
+This returns the list of methods which have been associated with the
+attribute.
+
+=item B<< $attr->install_accessors >>
+
+This method generates and installs code the attributes various
+accessors. It is typically called from the L<Class::MOP::Class>
+C<add_attribute> method.
+
+=item B<< $attr->remove_accessors >>
+
+This method removes all of the accessors associated with the
+attribute.
+
+This does not currently remove methods from the list returned by
+C<associated_methods>.
+
+=item B<< $attr->inline_get >>
+
+=item B<< $attr->inline_set >>
+
+=item B<< $attr->inline_has >>
+
+=item B<< $attr->inline_clear >>
+
+These methods return a code snippet suitable for inlining the relevant
+operation. They expect strings containing variable names to be used in the
+inlining, like C<'$self'> or C<'$_[1]'>.
+
+=back
+
+=head2 Introspection
+
+=over 4
+
+=item B<< Class::MOP::Attribute->meta >>
+
+This will return a L<Class::MOP::Class> instance for this class.
+
+It should also be noted that L<Class::MOP> will actually bootstrap
+this module by installing a number of attribute meta-objects into its
+metaclass.
+
+=back
+
+=head1 AUTHORS
+
+=over 4
+
+=item *
+
+Stevan Little <stevan.little@iinteractive.com>
+
+=item *
+
+Dave Rolsky <autarch@urth.org>
+
+=item *
+
+Jesse Luehrs <doy@tozt.net>
+
+=item *
+
+Shawn M Moore <code@sartak.org>
+
+=item *
+
+יובל קוג'מן (Yuval Kogman) <nothingmuch@woobling.org>
+
+=item *
+
+Karen Etheridge <ether@cpan.org>
+
+=item *
+
+Florian Ragwitz <rafl@debian.org>
+
+=item *
+
+Hans Dieter Pearcey <hdp@weftsoar.net>
+
+=item *
+
+Chris Prather <chris@prather.org>
+
+=item *
+
+Matt S Trout <mst@shadowcat.co.uk>
+
+=back
+
+=head1 COPYRIGHT AND LICENSE
+
+This software is copyright (c) 2006 by Infinity Interactive, Inc..
+
+This is free software; you can redistribute it and/or modify it under
+the same terms as the Perl 5 programming language system itself.
+
+=cut