I've tried to use this technique, in a query: Checking all of facts in prolog . And seen this which is probably the same as my question. Reporting *why* a query failed in Prolog in a systematic way .
Specifically I am trying to define chess rules. I want to say:
there is no king capture, that can't be blocked by a pawn or a ray with the same move.
hello(X, F, T) :-
turn_king(K),
\+ (\+ ( block_ray_move(X, K, F, T)
; block_pawn_move(X, K, F, T)
),
cnt r_king_captures(X)
).
I haven't tested this, but I am assuming it is logically correct. One problem might be, this fails either there is no king captures, or there is no block to a king capture.
So how should I restructure the logic, so I can tell between the two possibilities.
