The DCI library for Ruby is a fairly faithful implementation of the DCI concepts developed by Trygve Reenskaug, Reenskaug, and James O. Coplien.
It defines two reusable base classes, the Role and Context. The best way to understand their usage is to look at the QED documentation provided (for example).
The usual RubyGems install procedure:
$ gem install dci
Copyright (c) 2012 Rubyworks. All rights reserved.
DCI for Ruby is distributable under the terms of BSD-2-Clause license.
See COPYING.md file for license details.