From: Kirill Shutemov <k.shutemov@...>
Date: 2005-05-11T15:58:40+09:00
Subject: options parsing: required and conflict

Can I define options dependencies using OptionParser? 
For example: if user defines option --option-a than he has to define
option --option-b or --option-c and mustn't define --option-d and
--option-e.
Is it possible?