constant::Atom - unique symbols
enum::fields - Perl extension for defining constants for use in Array-based objects
enum::hash - create a hash of 'enum's, with the same interface as enum.pm
lib::http - Uses a Perl libray diretory over the internet using the HTTP protocol.
vars::global - try to make global variables a little safer
version::AlphaBeta - Use alphanumeric version objects
version::Limit - Perl extension for fine control of permitted versions