Tie::RefHash(3pm)

1Tie::RefHash(3pm)      Perl Programmers Reference Guide      Tie::RefHash(3pm)
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NAME

6       Tie::RefHash - use references as hash keys
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SYNOPSIS

9           require 5.004;
10           use Tie::RefHash;
11           tie HASHVARIABLE, 'Tie::RefHash', LIST;
12           tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;
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14           untie HASHVARIABLE;
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DESCRIPTION

17       This module provides the ability to use references as hash keys if you
18       first "tie" the hash variable to this module.  Normally, only the keys
19       of the tied hash itself are preserved as references; to use references
20       as keys in hashes-of-hashes, use Tie::RefHash::Nestable, included as
21       part of Tie::RefHash.
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23       It is implemented using the standard perl TIEHASH interface.  Please
24       see the "tie" entry in perlfunc(1) and perltie(1) for more information.
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26       The Nestable version works by looking for hash references being stored
27       and converting them to tied hashes so that they too can have references
28       as keys.  This will happen without warning whenever you store a
29       reference to one of your own hashes in the tied hash.
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EXAMPLE

32           use Tie::RefHash;
33           tie %h, 'Tie::RefHash';
34           $a = [];
35           $b = {};
36           $c = \*main;
37           $d = \"gunk";
38           $e = sub { 'foo' };
39           %h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5);
40           $a->[0] = 'foo';
41           $b->{foo} = 'bar';
42           for (keys %h) {
43              print ref($_), "\n";
44           }
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46           tie %h, 'Tie::RefHash::Nestable';
47           $h{$a}->{$b} = 1;
48           for (keys %h, keys %{$h{$a}}) {
49              print ref($_), "\n";
50           }
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THREAD SUPPORT

53       Tie::RefHash fully supports threading using the "CLONE" method.
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STORABLE SUPPORT

56       Storable hooks are provided for semantically correct serialization and
57       cloning of tied refhashes.
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RELIC SUPPORT

60       This version of Tie::RefHash seems to no longer work with 5.004. This
61       has not been throughly investigated. Patches welcome ;-)
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LICENSE

64       This program is free software; you can redistribute it and/or modify it
65       under the same terms as Perl itself
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MAINTAINER

68       Yuval Kogman <nothingmuch@woobling.org>
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AUTHOR

71       Gurusamy Sarathy        gsar@activestate.com
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73       'Nestable' by Ed Avis   ed@membled.com
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