| Tie::RefHash - use references as hash keys |
Tie::RefHash - use references as hash keys
require 5.004;
use Tie::RefHash;
tie HASHVARIABLE, 'Tie::RefHash', LIST;
tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;
untie HASHVARIABLE;
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.
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";
}
the Tie::RefHash manpage fully supports threading using the CLONE method.
the Storable manpage hooks are provided for semantically correct serialization and cloning of tied refhashes.
This version of Tie::RefHash seems to no longer work with 5.004. This has not been throughly investigated. Patches welcome ;-)
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself
Yuval Kogman <nothingmuch@woobling.org>
Gurusamy Sarathy gsar@activestate.com
'Nestable' by Ed Avis ed@membled.com
perl(1), perlfunc(1), perltie(1)
| Tie::RefHash - use references as hash keys |