Tie::RefHash

Tie::RefHash(3)	       Perl Programmers Reference Guide	      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 informa-
       tion.

       The Nestable version works by looking for hash references being stored
       and converting them to tied hashes so that they too can have refer-
       ences 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 1.32

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



perl v5.8.8			  2001-09-21		      Tie::RefHash(3)