focal (3) Tie::RefHash.3perl.gz

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)