Prolog (Programming in Logic) is a programming language based on Predicate Logic. It uses the restricted syntax known as Horn Clauses.

Monty Python and the Holy Grail (1975)
The witchConnie Booth
Sir Bedevere (etc.)Terry Jones
King ArthurGraham Chapman
Mr. Blint (a village n'er do well very keen on burning witches) (etc.) Eric Idle
Mr. Newt (a village blacksmith quite interested in burning witches) (etc.) John Cleese
Mr. Duck (a village carpenter who is almost keener than anyone else to burn witches) (etc.) Michael Palin
Directed byTerry Gilliam, Terry Jones
-- must be © the Pythons


[All83] L. Allison, 'An executable Prolog semantics', Algol Bulletin, vol.50, pp.10-18,, December 1983
And other publications.