NAME

       Tie::RefHash - use references as hash keys

SYNOPSIS

           require 5.004;
           use Tie::RefHash;
           tie HASHVARIABLE, 'Tie::RefHash', LIST;
           tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;

           untie HASHVARIABLE;

DESCRIPTION

       This module provides the ability to use references as hash keys if you first "tie" the
       hash variable to this module.  Normally, only the keys of the tied hash itself are
       preserved as references; to use references as keys in hashes-of-hashes, use
       Tie::RefHash::Nestable, included as part of Tie::RefHash.

       It is implemented using the standard perl TIEHASH interface.  Please see the "tie" entry
       in perlfunc(1) and perltie(1) for more information.

       The Nestable version works by looking for hash references being stored and converting them
       to tied hashes so that they too can have references as keys.  This will happen without
       warning whenever you store a reference to one of your own hashes in the tied hash.

EXAMPLE

           use Tie::RefHash;
           tie %h, 'Tie::RefHash';
           $a = [];
           $b = {};
           $c = \*main;
           $d = \"gunk";
           $e = sub { 'foo' };
           %h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5);
           $a->[0] = 'foo';
           $b->{foo} = 'bar';
           for (keys %h) {
              print ref($_), "\n";
           }

           tie %h, 'Tie::RefHash::Nestable';
           $h{$a}->{$b} = 1;
           for (keys %h, keys %{$h{$a}}) {
              print ref($_), "\n";
           }

THREAD SUPPORT

       Tie::RefHash fully supports threading using the "CLONE" method.

STORABLE SUPPORT

       Storable hooks are provided for semantically correct serialization and cloning of tied
       refhashes.

RELIC SUPPORT

       This version of Tie::RefHash seems to no longer work with 5.004. This has not been
       throughly investigated. Patches welcome ;-)

LICENSE

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

MAINTAINER

       Yuval Kogman <nothingmuch@woobling.org>

AUTHOR

       Gurusamy Sarathy        gsar@activestate.com

       'Nestable' by Ed Avis   ed@membled.com

SEE ALSO

       perl(1), perlfunc(1), perltie(1)