This is demo of automatic programming using Prolog
(c) Dmitry Ponyatov dponyatov@gmail.com
github: https://github.com/ponyatov/PROcompiler
https://www.cl.cam.ac.uk/teaching/0708/Prolog/prolog-additional.pdf
http://www.eecs.yorku.ca/course_archive/2004-05/S/3401/notes/grammars.pdf