NAME

       Hash::Case - base class for hashes with key-casing requirements

INHERITANCE

        Hash::Case
          is a Tie::StdHash

        Hash::Case is extended by
          Hash::Case::Lower
          Hash::Case::Preserve
          Hash::Case::Upper

SYNOPSIS

        use Hash::Case::Lower;
        tie my(%lchash), 'Hash::Case::Lower';
        $lchash{StraNGeKeY} = 3;
        print keys %lchash;  # strangekey

DESCRIPTION

       Hash::Case is the base class for various classes which tie special treatment for the
       casing of keys.  Be aware of the differences in implementation: "Lower" and "Upper" are
       tied native hashes: these hashes have no need for hidden fields or other assisting data
       structured.  A case "Preserve" hash will actually create three hashes.

       The following strategies are implemented:

       •   Hash::Case::Lower (native hash)

           Keys are always considered lower case. The internals of this module translate any
           incoming key to lower case before it is used.

       •   Hash::Case::Upper (native hash)

           Like the ::Lower, but then all keys are always translated into upper case.  This
           module can be of use for some databases, which do translate everything to capitals as
           well.  To avoid confusion, you may want to have you own internal Perl hash do this as
           well.

       •   Hash::Case::Preserve

           The actual casing is ignored, but not forgotten.

METHODS

   Constructors
       $obj->addHashData(HASH)
           Add the data of a hash (passed as reference) to the created tied hash.  The existing
           values in the hash remain, the keys are adapted to the needs of the the casing.

       $obj->addPairs(PAIRS)
           Specify an even length list of alternating key and value to be stored in the hash.

       $obj->setHash(HASH)
           The functionality differs for native and wrapper hashes.  For native hashes, this is
           the same as first clearing the hash, and then a call to addHashData().  Wrapper hashes
           will use the hash you specify here to store the data, and re-create the mapping hash.

       tie(HASH, TIE, [VALUES,] OPTIONS)
           Tie the HASH with the TIE package which extends Hash::Case.  The OPTIONS differ per
           implementation: read the manual page for the package you actually use.  The VALUES is
           a reference to an array containing key-value pairs, or a reference to a hash: they
           fill the initial hash.

           example:

            my %x;
            tie %x, 'Hash::Case::Lower';
            $x{Upper} = 3;
            print keys %x;       # 'upper'

            my @y = (ABC => 3, DeF => 4);
            tie %x, 'Hash::Case::Lower', \@y;
            print keys %x;       # 'abc' 'def'

            my %z = (ABC => 3, DeF => 4);
            tie %x, 'Hash::Case::Lower', \%z;

SEE ALSO

       This module is part of Hash-Case distribution version 1.05, built on February 06, 2020.
       Website: http://perl.overmeer.net/CPAN/

LICENSE

       Copyrights 2002-2020 by [Mark Overmeer <markov@cpan.org>]. For other contributors see
       ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.  See http://dev.perl.org/licenses/