use Class::MOP::Method::Accessor;
use Carp 'confess';
-use Scalar::Util 'blessed', 'reftype', 'weaken';
+use Scalar::Util 'blessed', 'weaken';
-our $VERSION = '0.16';
+our $VERSION = '0.62';
our $AUTHORITY = 'cpan:STEVAN';
use base 'Class::MOP::Object';
-sub meta {
- require Class::MOP::Class;
- Class::MOP::Class->initialize(blessed($_[0]) || $_[0]);
-}
-
# NOTE: (meta-circularity)
# This method will be replaced in the
# boostrap section of Class::MOP, by
} else {
(is_default_a_coderef(\%options))
|| confess("References are not allowed as default values, you must ".
- "wrap then in a CODE reference (ex: sub { [] } and not [])")
+ "wrap the default of '$name' in a CODE reference (ex: sub { [] } and not [])")
if exists $options{default} && ref $options{default};
}
+ if( $options{required} and not( defined($options{builder}) || defined($options{init_arg}) || exists $options{default} ) ) {
+ confess("A required attribute must have either 'init_arg', 'builder', or 'default'");
+ }
bless {
'$!name' => $name,
'$!accessor' => $options{accessor},
'$!reader' => $options{reader},
- '$!writer' => $options{writer},
- '$!predicate' => $options{predicate},
- '$!clearer' => $options{clearer},
- '$!builder' => $options{builder},
- '$!init_arg' => $options{init_arg},
- '$!default' => $options{default},
+ '$!writer' => $options{writer},
+ '$!predicate' => $options{predicate},
+ '$!clearer' => $options{clearer},
+ '$!builder' => $options{builder},
+ '$!init_arg' => $options{init_arg},
+ '$!default' => $options{default},
+ '$!initializer' => $options{initializer},
# keep a weakened link to the
# class we are associated with
'$!associated_class' => undef,
# and a list of the methods
# associated with this attr
'@!associated_methods' => [],
+ # NOTE:
+ # protect this from silliness
+ init_arg => undef,
} => $class;
}
my ($self, $meta_instance, $instance, $params) = @_;
my $init_arg = $self->{'$!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)
- if (!defined $val && defined $self->{'$!default'}) {
- $val = $self->default($instance);
- } elsif (!defined $val && defined( my $builder = $self->{'$!builder'})) {
- if($builder = $instance->can($builder) ){
- $val = $instance->$builder;
- } else {
- confess(blessed($instance)." does not support builder method '$builder' for attribute '" . $self->name . "'");
+ if(defined $init_arg and exists $params->{$init_arg}){
+ $self->_set_initial_slot_value(
+ $meta_instance,
+ $instance,
+ $params->{$init_arg},
+ );
+ }
+ elsif (defined $self->{'$!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 {
+ confess(blessed($instance)." does not support builder method '". $self->{'$!builder'} ."' for attribute '" . $self->name . "'");
}
}
- $meta_instance->set_slot_value($instance, $self->name, $val);
+}
+
+sub _set_initial_slot_value {
+ my ($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 = sub {
+ $meta_instance->set_slot_value($instance, $slot_name, $_[0]);
+ };
+
+ my $initializer = $self->initializer;
+
+ # most things will just want to set a value, so make it first arg
+ $instance->$initializer($value, $callback, $self);
}
# NOTE:
sub associated_class { $_[0]->{'$!associated_class'} }
sub associated_methods { $_[0]->{'@!associated_methods'} }
-sub has_accessor { defined($_[0]->{'$!accessor'}) ? 1 : 0 }
-sub has_reader { defined($_[0]->{'$!reader'}) ? 1 : 0 }
-sub has_writer { defined($_[0]->{'$!writer'}) ? 1 : 0 }
-sub has_predicate { defined($_[0]->{'$!predicate'}) ? 1 : 0 }
-sub has_clearer { defined($_[0]->{'$!clearer'}) ? 1 : 0 }
-sub has_builder { defined($_[0]->{'$!builder'}) ? 1 : 0 }
-sub has_init_arg { defined($_[0]->{'$!init_arg'}) ? 1 : 0 }
-sub has_default { defined($_[0]->{'$!default'}) ? 1 : 0 }
-
-sub accessor { $_[0]->{'$!accessor'} }
-sub reader { $_[0]->{'$!reader'} }
-sub writer { $_[0]->{'$!writer'} }
-sub predicate { $_[0]->{'$!predicate'} }
-sub clearer { $_[0]->{'$!clearer'} }
-sub builder { $_[0]->{'$!builder'} }
-sub init_arg { $_[0]->{'$!init_arg'} }
+sub has_accessor { defined($_[0]->{'$!accessor'}) ? 1 : 0 }
+sub has_reader { defined($_[0]->{'$!reader'}) ? 1 : 0 }
+sub has_writer { defined($_[0]->{'$!writer'}) ? 1 : 0 }
+sub has_predicate { defined($_[0]->{'$!predicate'}) ? 1 : 0 }
+sub has_clearer { defined($_[0]->{'$!clearer'}) ? 1 : 0 }
+sub has_builder { defined($_[0]->{'$!builder'}) ? 1 : 0 }
+sub has_init_arg { defined($_[0]->{'$!init_arg'}) ? 1 : 0 }
+sub has_default { defined($_[0]->{'$!default'}) ? 1 : 0 }
+sub has_initializer { defined($_[0]->{'$!initializer'}) ? 1 : 0 }
+
+sub accessor { $_[0]->{'$!accessor'} }
+sub reader { $_[0]->{'$!reader'} }
+sub writer { $_[0]->{'$!writer'} }
+sub predicate { $_[0]->{'$!predicate'} }
+sub clearer { $_[0]->{'$!clearer'} }
+sub builder { $_[0]->{'$!builder'} }
+sub init_arg { $_[0]->{'$!init_arg'} }
+sub initializer { $_[0]->{'$!initializer'} }
# end bootstrapped away method section.
# (all methods below here are kept intact)
-sub get_read_method { $_[0]->reader || $_[0]->accessor }
-sub get_write_method { $_[0]->writer || $_[0]->accessor }
+sub has_read_method { $_[0]->has_reader || $_[0]->has_accessor }
+sub has_write_method { $_[0]->has_writer || $_[0]->has_accessor }
+
+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 $code;
+ }
+ }
+}
sub is_default_a_coderef {
- ('CODE' eq (reftype($_[0]->{'$!default'} || $_[0]->{default}) || ''))
+ ('CODE' eq ref($_[0]->{'$!default'} || $_[0]->{default}))
}
sub default {
## Slot management
+sub set_initial_value {
+ my ($self, $instance, $value) = @_;
+ $self->_set_initial_slot_value(
+ Class::MOP::Class->initialize(blessed($instance))->get_meta_instance,
+ $instance,
+ $value
+ );
+}
+
sub set_value {
my ($self, $instance, $value) = @_;
sub has_value {
my ($self, $instance) = @_;
- defined Class::MOP::Class->initialize(blessed($instance))
- ->get_meta_instance
- ->get_slot_value($instance, $self->name) ? 1 : 0;
+ Class::MOP::Class->initialize(blessed($instance))
+ ->get_meta_instance
+ ->is_slot_initialized($instance, $self->name);
}
sub clear_value {
sub process_accessors {
my ($self, $type, $accessor, $generate_as_inline_methods) = @_;
- if (reftype($accessor)) {
- (reftype($accessor) eq 'HASH')
+ if (ref($accessor)) {
+ (ref($accessor) eq 'HASH')
|| confess "bad accessor/reader/writer/predicate/clearer format, must be a HASH ref";
my ($name, $method) = %{$accessor};
- $method = $self->accessor_metaclass->wrap($method);
+ $method = $self->accessor_metaclass->wrap(
+ $method,
+ package_name => $self->associated_class->name,
+ name => $name,
+ );
$self->associate_method($method);
return ($name, $method);
}
attribute => $self,
is_inline => $inline_me,
accessor_type => $type,
+ package_name => $self->associated_class->name,
+ name => $accessor,
);
};
confess "Could not create the '$type' method for " . $self->name . " because : $@" if $@;
{
my $_remove_accessor = sub {
my ($accessor, $class) = @_;
- if (reftype($accessor) && reftype($accessor) eq 'HASH') {
+ if (ref($accessor) && ref($accessor) eq 'HASH') {
($accessor) = keys %{$accessor};
}
my $method = $class->get_method($accessor);
MyClass->meta->construct_instance(-foo => "Hello There");
In an init_arg is not assigned, it will automatically use the
-value of C<$name>.
-
-=item I<default>
-
-The value of this key is the default value which
-C<Class::MOP::Class::construct_instance> will initialize the
-attribute to.
+value of C<$name>. If an explicit C<undef> is given for an init_arg,
+an attribute value can't be specified during initialization.
=item I<builder>
This should be a method in the class associated with the attribute,
not a method in the attribute class itself.
+=item I<default>
+
+The value of this key is the default value which
+C<Class::MOP::Class::construct_instance> will initialize the
+attribute to.
+
B<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
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 I<default> value is a CODE
-reference, it is passed the raw (unblessed) instance structure
+reference, it is passed the (as yet unfinished) instance structure
as it's only argument. So you can do things like this:
Class::MOP::Attribute->new('$object_identity' => (
this class to acheive it. However, this is currently left as
an exercise to the reader :).
+=item I<initializer>
+
+This may be a method name (referring to a method on the class with this
+attribute) or a CODE ref. The initializer is used to set the attribute value
+on an instance when the attribute is set during instance initialization. When
+called, it is passed the instance (as the invocant), the value to set, a
+slot-setting CODE ref, and the attribute meta-instance. The slot-setting code
+is provided to make it easy to set the (possibly altered) value on the instance
+without going through several more method calls.
+
+This contrived example shows an initializer that sets the attribute to twice
+the given value.
+
+ Class::MOP::Attribute->new('$doubled' => (
+ initializer => sub {
+ my ($instance, $value, $set) = @_;
+ $set->($value * 2);
+ },
+ ));
+
+As method names can be given as initializers, one can easily make
+attribute initialization use the writer:
+
+ Class::MOP::Attribute->new('$some_attr' => (
+ writer => 'some_attr',
+ initializer => 'some_attr',
+ ));
+
+Your writer will simply need to examine it's C<@_> and determine under
+which context it is being called.
+
=back
The I<accessor>, I<reader>, I<writer>, I<predicate> and I<clearer> keys can
=item I<predicate>
-This is a basic test to see if the value of the attribute is not
-C<undef>. It will return true (C<1>) if the attribute's value is
-defined, and false (C<0>) otherwise.
+This is a basic test to see if any value has been set for the
+attribute. It will return true (C<1>) if the attribute has been set
+to any value (even C<undef>), and false (C<0>) otherwise.
+
+B<NOTE:>
+The predicate will return true even when you set an attribute's
+value to C<undef>. This behaviour has changed as of version 0.43. In
+older versions, the predicate (erroneously) checked for attribute
+value definedness, instead of presence as it is now.
+
+If you really want to get rid of the value, you have to define and
+use a I<clearer> (see below).
=item I<clearer>
=item B<clone (%options)>
+This will return a clone of the attribute instance, allowing the overriding
+of various attributes through the C<%options> supplied.
+
=item B<initialize_instance_slot ($instance, $params)>
+This method is used internally to initialize the approriate slot for this
+attribute in a given C<$instance>, the C<$params> passed are those that were
+passed to the constructor.
+
=back
=head2 Value management
Set the value without going through the accessor. Note that this may be done to
even attributes with just read only accessors.
+=item B<set_initial_value ($instance, $value)>
+
+This method sets the value without going through the accessor -- but it is only
+called when the instance data is first initialized.
+
=item B<get_value ($instance)>
Return the value without going through the accessor. Note that this may be done
=item B<has_value ($instance)>
-Returns a boolean indicating if the item in the C<$instance> has a value in it.
+Return a boolean indicating if the item in the C<$instance> has a value in it.
This is basically what the default C<predicate> method calls.
=item B<clear_value ($instance)>
=item B<clearer>
+=item B<initializer>
+
=item B<init_arg>
=item B<is_default_a_coderef>
=item B<default (?$instance)>
-As noted in the documentation for C<new> above, if the I<default>
-value is a CODE reference, this accessor will pass a single additional
-argument C<$instance> into it and return the value.
+Return the default value for the attribute.
+
+If you pass in an C<$instance> argument to this accessor and the
+I<default> is a CODE reference, then the CODE reference will be
+executed with the C<$instance> as its argument.
=item B<slots>
-Returns a list of slots required by the attribute. This is usually
+Return a list of slots required by the attribute. This is usually
just one, which is the name of the attribute.
=item B<get_read_method>
=item B<get_write_method>
-Return the name of a method suitable for reading / writing the value of the
-attribute in the associated class. Suitable for use whether C<reader> and
-C<writer> or C<accessor> was used.
+Return the name of a method name suitable for reading / writing the value
+of the attribute in the associated class. Suitable for use whether
+C<reader> and C<writer> or C<accessor> was used.
+
+=item B<get_read_method_ref>
+
+=item B<get_write_method_ref>
+
+Return the CODE reference of a method suitable for reading / writing the
+value of the attribute in the associated class. Suitable for use whether
+C<reader> and C<writer> or C<accessor> was specified or not.
+
+NOTE: If no reader/writer/accessor was specified, this will use the
+attribute get_value/set_value methods, which can be very inefficient.
+
+=item B<has_read_method>
+
+=item B<has_write_method>
+
+Return whether a method exists suitable for reading / writing the value
+of the attribute in the associated class. Suitable for use whether
+C<reader> and C<writer> or C<accessor> was used.
=back
=item B<has_clearer>
+=item B<has_initializer>
+
=item B<has_init_arg>
=item B<has_default>
+=item B<has_builder>
+
=back
=head2 Class association
=item B<associated_methods>
This will return the list of methods which have been associated with
-the C<associate_method> methods.
+the C<associate_method> methods. This is a good way of seeing what
+methods are used to manage a given attribute.
=item B<install_accessors>
It should also be noted that B<Class::MOP> will actually bootstrap
this module by installing a number of attribute meta-objects into
-it's metaclass. This will allow this class to reap all the benifits
+it's metaclass. This will allow this class to reap all the benefits
of the MOP when subclassing it.
=back
=head1 COPYRIGHT AND LICENSE
-Copyright 2006, 2007 by Infinity Interactive, Inc.
+Copyright 2006-2008 by Infinity Interactive, Inc.
L<http://www.iinteractive.com>
projects / gitmo/Class-MOP.git / blobdiff