NAME

ClassEncapsulatedAttributes - A set of example metaclasses with class encapsulated attributes

SYNOPSIS

  package Foo;

  use metaclass 'ClassEncapsulatedAttributes';

  Foo->meta->add_attribute('foo' => (
      accessor  => 'Foo_foo',
      default   => 'init in FOO'
  ));

  sub new  {
      my $class = shift;
      $class->meta->new_object(@_);
  }

  package Bar;
  our @ISA = ('Foo');

  # duplicate the attribute name here
  Bar->meta->add_attribute('foo' => (
      accessor  => 'Bar_foo',
      default   => 'init in BAR'
  ));

  # ... later in other code ...

  my $bar = Bar->new();
  prints $bar->Bar_foo(); # init in BAR
  prints $bar->Foo_foo(); # init in FOO

  # and ...

  my $bar = Bar->new(
      'Foo' => { 'foo' => 'Foo::foo' },
      'Bar' => { 'foo' => 'Bar::foo' }
  );

  prints $bar->Bar_foo(); # Foo::foo
  prints $bar->Foo_foo(); # Bar::foo

DESCRIPTION

This is an example metaclass which encapsulates a class's attributes on a per-class basis. This means that there is no possibility of name clashes with inherited attributes. This is similar to how C++ handles its data members.

ACKNOWLEDGEMENTS

Thanks to Yuval "nothingmuch" Kogman for the idea for this example.

AUTHORS

Stevan Little <stevan@iinteractive.com>

Yuval Kogman <nothingmuch@woobling.com>

COPYRIGHT AND LICENSE

Copyright 2006-2008 by Infinity Interactive, Inc.

http://www.iinteractive.com

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.