DCTG-GP is a Prolog-based GP system. It uses a logic-based attribute grammar called a DCTG (Definite Clause Translation Grammar) to define the target language for the genetic programming expressions. DCTG's let you define all aspects of the GP language in one definition. This is very convenient for concisely defining both the syntax and semantics of the language. In addition, grammatical constraints can be introduced into the grammar definition. This permits simplification of the solution space, and can help evolutionary performance. DCTG-GP is free to download and use. It has minimal documentation, and is not supported.
Back up: http://www.cosc.brocku.ca/~bross/