Hash::Case 1.003

CLASS HIERARCHY

Hash::Case
is a Tie::StdHash
is a Tie::Hash

SYNOPSIS

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

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

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.

Examples:

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;
addPairs PAIRS

Specify an even length list of alternating key and value to be stored in the hash.

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.

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.