Tie::RefHash(3) Perl Programmers Reference Guide Tie::RefHash(3)NAMETie::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(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
VERSION
Version 1.3 8 Apr 2001
SEE ALSOperl(1), perlfunc(1), perltie(1)2001-02-22 perl v5.6.1 Tie::RefHash(3)
