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Tie::RefHash(3)
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";
      }

AUTHOR
  Gurusamy Sarathy	  gsar@activestate.com

  'Nestable' by Ed Avis	  ed@membled.com

VERSION
  Version 1.30

SEE ALSO
  perl(1), perlfunc(1), perltie(1)

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