002/src/life.ml

   1 type direction =
   2   N | NE | E | SE | S | SW | W | NW
   3
   4
   5 let directions =
   6   [N; NE; E; SE; S; SW; W; NW]
   7
   8
   9 let offset = function
  10   (* direction -> x, y *)
  11   | N  ->  0, -1
  12   | NE ->  1, -1
  13   | E  ->  1,  0
  14   | SE ->  1,  1
  15   | S  ->  0,  1
  16   | SW -> -1,  1
  17   | W  -> -1,  0
  18   | NW -> -1, -1
  19
  20
  21 (* Hack to sleep less than 1 sec *)
  22 let minisleep subsec =
  23   ignore (Unix.select [] [] [] subsec)
  24
  25
  26 let init_board x y =
  27   Array.map (Array.map (fun _ -> Random.int 2)) (Array.make_matrix x y 0)
  28
  29
  30 let print_board board =
  31   Array.iter (fun row -> Array.iter (print_int) row; print_newline ()) board
  32
  33
  34 let new_state = function
  35   | 1, live_neighbors when live_neighbors < 2 -> 0
  36   | 1, live_neighbors when live_neighbors < 4 -> 1
  37   | 1, live_neighbors when live_neighbors > 3 -> 0
  38   | 0, live_neighbors when live_neighbors = 3 -> 1
  39   | state, _ -> state
  40
  41
  42 let filter_offsides width height neighbors =
  43   List.filter
  44   (fun (x, y) -> x >= 0 && y >= 0 && x < width && y < height)
  45   neighbors
  46
  47
  48 let new_generation board =
  49   let height = Array.length board
  50   and width = Array.length board.(0) in
  51   Array.mapi
  52   (
  53     fun i_y row ->
  54       Array.mapi
  55       (fun i_x state->
  56         let neighbors =
  57           List.map
  58           (fun d ->
  59             let off_x, off_y = offset d in
  60             (i_x + off_x), (i_y + off_y)
  61           )
  62           directions
  63         in
  64         let neighbors = filter_offsides width height neighbors in
  65         let states = List.map (fun (x, y) -> board.(y).(x)) neighbors in
  66         let live_neighbors = List.fold_left (+) 0 states in
  67         let state = new_state (state, live_neighbors) in
  68         state
  69       )
  70       row
  71   )
  72   board
  73
  74
  75 let rec life_loop board =
  76   print_board board;
  77   print_newline ();
  78   minisleep 0.1;
  79   life_loop (new_generation board)
  80
  81
  82 let main x y =
  83   Random.init (int_of_float (Unix.time ()));
  84
  85   life_loop (init_board x y)
  86
  87
  88 let () = main 61 236