Tie::CPHash(3)

NAME
Tie::CPHash - Case preserving but case insensitive hash table

VERSION
This document describes version 1.04 of Tie::CPHash, released April 26, 2008.

SYNOPSIS
    require Tie::CPHash;
    tie %cphash, 'Tie::CPHash';

    $cphash{'Hello World'} = 'Hi there!';
    printf("The key `%s' was used to store `%s'.\n",
           tied(%cphash)->key('HELLO WORLD'),
           $cphash{'HELLO world'});

DESCRIPTION
The Tie::CPHash module provides a hash table that is case preserving but case insensitive. This means that

    $cphash{KEY}    $cphash{key}
    $cphash{Key}    $cphash{keY}

all refer to the same entry. Also, the hash remembers which form of the key was last used to store the entry. The "keys" and "each" functions will return the key that was used to set the value.

An example should make this clear:

    tie %h, 'Tie::CPHash';
    $h{Hello} = 'World';
    print $h{HELLO};            # Prints 'World'
    print keys(%h);             # Prints 'Hello'
    $h{HELLO} = 'WORLD';
    print $h{hello};            # Prints 'WORLD'
    print keys(%h);             # Prints 'HELLO'

The additional "key" method lets you fetch the case of a specific key:

    # When run after the previous example, this prints 'HELLO':
    print tied(%h)->key('Hello');

(The "tied" function returns the object that %h is tied to.)

If you need a case insensitive hash, but don't need to preserve case, just use $hash{lc $key} instead of $hash{$key}. This has a lot less overhead than Tie::CPHash.

AUTHOR
Christopher J. Madsen "<perl AT cjmweb.net>"

Please report any bugs or feature requests to "<bug-Tie-CPHash AT rt.cpan.org>", or through the web interface at <http://rt.cpan.org/Public/Bug/Report.html?Queue=Tie-CPHash>

LICENSE AND COPYRIGHT
Copyright 1997-2008 Christopher J. Madsen

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

DISCLAIMER OF WARRANTY
BECAUSE THIS SOFTWARE IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE SOFTWARE, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE SOFTWARE "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE SOFTWARE IS WITH YOU. SHOULD THE SOFTWARE PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR, OR CORRECTION.

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