NAME

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

VERSION

       This document describes version 2.000 of Tie::CPHash, released January 17, 2015.

SYNOPSIS

           use Tie::CPHash 2; # allows initialization during tie
           tie %cphash, 'Tie::CPHash', key => 'value';

           $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', 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'

       Tie::CPHash version 2.000 introduced the ability to pass a list of "key => value" pairs to initialize the
       hash (along with the "add" method that powers it).  The list must include a value for each key, or the
       constructor will croak.

       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.

       "use Tie::CPHash;" does not export anything into your namespace.

METHODS

   add
         tied(%h)->add( key => value, ... );
         tied(%h)->add( \@list_of_key_value_pairs );

       This method (introduced in version 2.000) adds keys and values to the hash.  It's just like

         %h = @list_of_key_value_pairs;

       except that it doesn't clear the hash first.  It accepts either a list or an arrayref.  It croaks if the
       list has an odd number of entries.  It returns the tied hash object.

       If the list contains duplicate keys, the last "key => value" pair in the list wins.  (You can't pass a
       hashref to "add" because it would be ambiguous which key would win if two keys differed only in case.)

       For people used to Tie::IxHash, "add" is aliased to both "Push" and "Unshift".  (Tie::CPHash does not
       preserve the order of keys.)

   key
         $set_using_key = tied(%h)->key( $key )

       This method lets you fetch the case of a specific key.  For example:

         $h{HELLO} = 'World';
         print tied(%h)->key('Hello'); # prints HELLO

       If the key does not exist in the hash, it returns "undef".

DIAGNOSTICS

       Odd number of elements in CPHash add
           You passed a list with an odd number of elements to the "add" method (or to "tie", which uses "add").
           The list must contain a value for each key.

CONFIGURATION AND ENVIRONMENT

       Tie::CPHash requires no configuration files or environment variables.

INCOMPATIBILITIES

       None reported.

BUGS AND LIMITATIONS

       No bugs have been reported.

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>.

       You can follow or contribute to Tie-CPHash's development at <https://github.com/madsen/tie-cphash>.

COPYRIGHT AND LICENSE

       This software is copyright (c) 2015 by Christopher J. Madsen.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.

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.

       IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY
       OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE SOFTWARE AS PERMITTED BY THE ABOVE LICENSE, BE LIABLE
       TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT OF
       THE USE OR INABILITY TO USE THE SOFTWARE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING
       RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE SOFTWARE TO OPERATE
       WITH ANY OTHER SOFTWARE), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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