Prolog gives you nondeterminism. That is, it can take incomplete or inconsistent input and provide partial or multiple answers. That's not behavior you want ver

Prolog gives you nondeterminism. That is, it can take incomplete or inconsistent input and provide partial or multiple answers. That's not behavior you want very often, but when it is, who else you gonna call? The specific, unique features of Prolog are unification, backtracking, and logic variables. People had high hopes for Prolog in the 1970s, but it proved to be a total disappointment. It was terribly slow and had a complicated performance model. These days, the niche for which Prolog is a good choice is very small. For combinatorial problems, Prolog has been superceded by extensions like Choco and Gecode and by easier and faster dedicated systems like Essence, Minion, and G12. Prolog is still sometimes chosen for small projects in constraint programming or text manipulation. Be sure to read this article on how Prolog really works. http://www.amzi.com/articles/prolog_under_the_hood.htm http://www.amzi.com/articles/prolog_under_the_hood.htm