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Text File  |  2000-01-01  |  698b  |  36 lines
  1. start:-
  2.     draw(3),
  3.     line(1000,1000,1000,31000),
  4.     line(1000,31000,31000,31000),
  5.     line(31000,31000,31000,1000),
  6.     line(31000,1000,1000,1000),
  7.     cs(15000,15000).
  8. start:-
  9.     text.
  10.     
  11. cs(X,Y):-
  12.     penpos(X,Y),
  13.     readchar(Z),
  14.     move1(Z,X,Y,X1,Y1),!,
  15.     cs(X1,Y1).
  16.     
  17. move1(`u,X,31000,X,31000):-!.
  18. move1(`u,X,Yold,X,Ynew):-!,
  19.     Ynew is Yold + 100,
  20.     dot(X,Yold).
  21. move1(`d,X,1000,X,1000):-!.
  22. move1(`d,X,Yold,X,Ynew):-!,
  23.     Ynew is Yold - 100,
  24.     dot(X,Yold).
  25. move1(`r,31000,Y,31000,Y):-!.
  26. move1(`r,Xold,Y,Xnew,Y):-!,
  27.     Xnew is Xold + 100,
  28.     dot(Xold,Y).
  29. move1(`l,1000,Y,1000,Y):-!.
  30. move1(`l,Xold,Y,Xnew,Y):-!,
  31.     Xnew is Xold - 100,
  32.     dot(Xold,Y).
  33. move1(`*,X,Y,X,Y):-!,
  34.     fail.
  35. move1(_,X,Y,X,Y).
  36.