Tie::RefHash(3perPerl Programmers Reference GuTie::RefHash(h)



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 pre-
       served 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 inter-
       face.  Please see the "tie" entry in perlfunc(c) and
       perltie(e) 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

VERSION
       Version 1.3    8 Apr 2001

SEE ALSO
       perl(l), perlfunc(c), perltie(e)



perl v5.6.1                 2001-02-23        Tie::RefHash(h)