Prolog

% Hello World in Prolog

hello :- display('Hello World!') , nl .

:- public main/0.

/*
:- visible pocet/1.
:- visible pole/2.
:- visible suradnice/2.
*/

main :- abolish(pole/2), abolish(pocet/1), abolish(suradnice/2),
        asserta(pocet(1)), asserta(pole(1,1)),
     cls,
     time(Y), write(Y),
        tmove(17,42), put(`o),
        tmove(2,55), write(5678), write(901), write(234),
        tmove(3,1), write(1), tmove(4,1), write(1),
     go,
        tmove(1,0),time(X), write(X), write(ok),
     preusporiadaj,
     zobrazuj.
main :- tmove(1,0),
     time(X), write(X), write(nak).

go :- call(pocet(61)).
go :- posun,
   go.

posun :- [! call(pole(X,Y)) !] , p(X,Y,X1,Y1), dobre(X1,Y1).
posun :- retract(pole(X,Y)), retract(pocet(P)), dec(P,P1), asserta(pocet(P1)),
      R is 18-X, S is 40+2*Y, tmove(R,S), put(32),
         tmove(3,P), put(32), tmove(4,P), put(32),
         !, fail.

p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
                   X1 is X+1, Y1 is Y+2, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
             X1 is X-1, Y1 is Y+2, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
             X1 is X+1, Y1 is Y-2, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
         X1 is X-1, Y1 is Y-2, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
         X1 is X+2, Y1 is Y+1, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
         X1 is X-2, Y1 is Y+1, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
         X1 is X+2, Y1 is Y-1, asserta(pole(X1,Y1)) !].
p(X,Y,X1,Y1) :- [! retract(pocet(P)), inc(P,P1), asserta(pocet(P1)),
         X1 is X-2, Y1 is Y-1, asserta(pole(X1,Y1)) !].

dobre(X,Y) :- retract(pole(X,Y)),
              ( call(pole(X,Y)) ; X<1 ; X>8 ; Y<1 ; Y>8 ),
        retract(pocet(P)), dec(P,P1), asserta(pocet(P1)),
        !, fail.
dobre(X,Y) :- asserta(pole(X,Y)),
        R is 18-X, S is 40+2*Y, tmove(R,S), put(`o),
              call(pocet(P1)), tmove(3,P1), write(X), tmove(4,P1), write(Y),
              !.

preusporiadaj :- call(pole(X,Y)), asserta(suradnice(X,Y)), fail.
preusporiadaj :- !.

zobrazuj :- call(suradnice(X,Y)),
      R is 18-X, S is 40+2*Y,
      tmove(R,S), put(`x),
      keyb(_,_),
      fail.
zobrazuj.

e :- edit(kuon).
/*
l :- listing.
l(X) :- listing(X).

pole(0,0).
pocet(58).
*/