Hash::Case(3) User Contributed Perl Documentation Hash::Case(3)NAMEHash::Case - base class for hashes with key-casing requirements
INHERITANCEHash::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
DESCRIPTIONHash::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
$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 1.006, built on
June 19, 2008. Website: http://perl.overmeer.net/hash-case/
LICENSE
Copyrights 2002-2003,2007-2008 by Mark Overmeer. 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://www.perl.com/perl/misc/Artistic.html
perl v5.14.1 2008-06-19 Hash::Case(3)
