fixed all the attribute name to be more Perl6ish and then removed the : in the init_a...

[gitmo/Class-MOP.git] / examples / InsideOutClass.pod

diff --git a/examples/InsideOutClass.pod b/examples/InsideOutClass.pod
index 62c1004..e106113 100644 (file)
--- a/examples/InsideOutClass.pod
+++ b/examples/InsideOutClass.pod
@@ -1,11 +1,99 @@
 
 package # hide the package from PAUSE
+    InsideOutClass::Attribute;
+
+use strict;
+use warnings;
+
+our $VERSION = '0.02';
+
+use Carp         'confess';
+use Scalar::Util 'refaddr';
+
+use base 'Class::MOP::Attribute';
+
+sub initialize_instance_slot {
+    my ($self, $meta_instance, $instance, $params) = @_;
+    my $init_arg = $self->init_arg;
+    # try to fetch the init arg from the %params ...
+    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);
+    }
+    my $_meta_instance = $self->associated_class->get_meta_instance;
+    $_meta_instance->initialize_slot($instance, $self->name);
+    $_meta_instance->set_slot_value($instance, $self->name, $val);
+}
+
+sub accessor_metaclass { 'InsideOutClass::Method::Accessor' }
+
+package # hide the package from PAUSE
+    InsideOutClass::Method::Accessor;
+    
+use strict;
+use warnings;
+
+our $VERSION = '0.01';
+
+use Carp         'confess';
+use Scalar::Util 'refaddr';
+
+use base 'Class::MOP::Method::Accessor';
+
+## Method generation helpers
+
+sub generate_accessor_method {
+    my $attr       = (shift)->associated_attribute;
+    my $meta_class = $attr->associated_class;  
+    my $attr_name  = $attr->name;
+    return sub {
+        my $meta_instance = $meta_class->get_meta_instance;
+        $meta_instance->set_slot_value($_[0], $attr_name, $_[1]) if scalar(@_) == 2;
+        $meta_instance->get_slot_value($_[0], $attr_name);
+    };
+}
+
+sub generate_reader_method {
+    my $attr       = (shift)->associated_attribute;
+    my $meta_class = $attr->associated_class;  
+    my $attr_name  = $attr->name;
+    return sub { 
+        confess "Cannot assign a value to a read-only accessor" if @_ > 1;
+        $meta_class->get_meta_instance
+                   ->get_slot_value($_[0], $attr_name); 
+    }; 
+}
+
+sub generate_writer_method {
+    my $attr       = (shift)->associated_attribute;
+    my $meta_class = $attr->associated_class;  
+    my $attr_name  = $attr->name;
+    return sub { 
+        $meta_class->get_meta_instance
+                   ->set_slot_value($_[0], $attr_name, $_[1]);
+    };
+}
+
+sub generate_predicate_method {
+    my $attr       = (shift)->associated_attribute;
+    my $meta_class = $attr->associated_class;  
+    my $attr_name  = $attr->name;
+    return sub { 
+        defined $meta_class->get_meta_instance
+                           ->get_slot_value($_[0], $attr_name) ? 1 : 0;
+    };   
+}
+
+package # hide the package from PAUSE
     InsideOutClass::Instance;
 
 use strict;
 use warnings;
 
-our $VERSION = '0.06';
+our $VERSION = '0.01';
 
 use Carp         'confess';
 use Scalar::Util 'refaddr';
@@ -19,29 +107,27 @@ sub create_instance {
 
 sub get_slot_value {
        my ($self, $instance, $slot_name) = @_;
-       $self->{meta}->get_package_variable('%' . $slot_name)->{refaddr $instance};
+       $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance};
 }
 
 sub set_slot_value {
        my ($self, $instance, $slot_name, $value) = @_;
-       $self->{meta}->get_package_variable('%' . $slot_name)->{refaddr $instance} = $value;
+       $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} = $value;
 }
 
 sub initialize_slot {
     my ($self, $instance, $slot_name) = @_;
-    $self->{meta}->add_package_variable(('%' . $slot_name) => {})
-        unless $self->{meta}->has_package_variable('%' . $slot_name); 
-    $self->{meta}->get_package_variable('%' . $slot_name)->{refaddr $instance} = undef;
+    $self->associated_metaclass->add_package_symbol(('%' . $slot_name) => {})
+        unless $self->associated_metaclass->has_package_symbol('%' . $slot_name); 
+    $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} = undef;
 }
 
 sub is_slot_initialized {
        my ($self, $instance, $slot_name) = @_;
-       return 0 unless $self->{meta}->has_package_variable('%' . $slot_name);
-       return exists $self->{meta}->get_package_variable('%' . $slot_name)->{refaddr $instance} ? 1 : 0;
+       return 0 unless $self->associated_metaclass->has_package_symbol('%' . $slot_name);
+       return exists $self->associated_metaclass->get_package_symbol('%' . $slot_name)->{refaddr $instance} ? 1 : 0;
 }
 
-## &remove_slot is left as an exercise for the reader :)
-
 1;
 
 __END__
@@ -56,11 +142,9 @@ InsideOutClass - A set of example metaclasses which implement the Inside-Out tec
 
   package Foo;
   
-  use metaclass 'Class::MOP::Class' => (
-     # tell our metaclass to use the 
-     # InsideOut attribute metclass 
-     # to construct all it's attributes
-    ':instance_metaclass' => 'InsideOutClass::Instance'
+  use metaclass (
+    ':attribute_metaclass' => 'InsideOutClass::Attribute',
+    ':instance_metaclass'  => 'InsideOutClass::Instance'
   );
   
   __PACKAGE__->meta->add_attribute('foo' => (
@@ -93,13 +177,11 @@ inside-out objects to be C<DESTROY>-ed, and some other details as
 well (threading, etc), but this is an example. A real implementation is left as
 an exercise to the reader.
 
-=head1 AUTHOR
+=head1 AUTHORS
 
 Stevan Little E<lt>stevan@iinteractive.comE<gt>
 
-=head1 SEE ALSO
-
-L<Tie::RefHash::Weak>
+Yuval Kogman E<lt>nothingmuch@woobling.comE<gt>
 
 =head1 COPYRIGHT AND LICENSE