Test Tictac

Jan Burse, created Sep 15. 2018
* Prolog code for the tic-tac-toe game.
* Min-max search via negation.
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* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* Restrictions
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* functionality to the library. Not to be distributed with additional
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* Trademarks
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% move(+Board, +Player, -Board)
move([[-,B,C],[D,E,F],[G,H,I]], P, [[P,B,C],[D,E,F],[G,H,I]]).
move([[A,-,C],[D,E,F],[G,H,I]], P, [[A,P,C],[D,E,F],[G,H,I]]).
move([[A,B,-],[D,E,F],[G,H,I]], P, [[A,B,P],[D,E,F],[G,H,I]]).
move([[A,B,C],[-,E,F],[G,H,I]], P, [[A,B,C],[P,E,F],[G,H,I]]).
move([[A,B,C],[D,-,F],[G,H,I]], P, [[A,B,C],[D,P,F],[G,H,I]]).
move([[A,B,C],[D,E,-],[G,H,I]], P, [[A,B,C],[D,E,P],[G,H,I]]).
move([[A,B,C],[D,E,F],[-,H,I]], P, [[A,B,C],[D,E,F],[P,H,I]]).
move([[A,B,C],[D,E,F],[G,-,I]], P, [[A,B,C],[D,E,F],[G,P,I]]).
move([[A,B,C],[D,E,F],[G,H,-]], P, [[A,B,C],[D,E,F],[G,H,P]]).
% init(+Board)
% win(+Board, +Player)
win([[P,P,P],[_,_,_],[_,_,_]], P).
win([[_,_,_],[P,P,P],[_,_,_]], P).
win([[_,_,_],[_,_,_],[P,P,P]], P).
win([[P,_,_],[P,_,_],[P,_,_]], P).
win([[_,P,_],[_,P,_],[_,P,_]], P).
win([[_,_,P],[_,_,P],[_,_,P]], P).
win([[P,_,_],[_,P,_],[_,_,P]], P).
win([[_,_,P],[_,P,_],[P,_,_]], P).
% other(+Player, -Player).
other(o, x).
other(x, o).
% tie(+Board, +Player)
tie(X, P) :-
\+ move(X, P, _).
% best(+Board, +Player, -Board)
best(X, P, Y) :-
move(X, P, Y),
( win(Y, P) -> true
; other(P, Q),
\+ tie(Y, Q),
\+ best(Y, Q, _)).
% tictac
best(X, x, _).