What is Visual Prolog
Visual Prolog is a logical programming language that counts PDC Prolog and Turbo Prolog as predecessors.

The goal of Visual Prolog is to support industrial strength programming of complex knowledge emphasized problems.

Today Visual Prolog is a very powerful and safe programming language combining the very best features of logical, functional and object-oriented programming paradigms in a consistent and elegant way.

Visual Prolog 7.1
Commercial Edition
for Windows Vista/XP/2000

http://www.visual-prolog.com/?gclid=COOY-aiUqo8CFRVrXgodYgiAlg