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 char_dead  = ' '
  10 let char_alive = 'o'
  11
  12
  13 let char_of_state = function
  14   | 0 -> char_dead
  15   | 1 -> char_alive
  16   | _ -> assert false
  17
  18
  19 let offset = function
  20   (* direction -> x, y *)
  21   | N  ->  0, -1
  22   | NE ->  1, -1
  23   | E  ->  1,  0
  24   | SE ->  1,  1
  25   | S  ->  0,  1
  26   | SW -> -1,  1
  27   | W  -> -1,  0
  28   | NW -> -1, -1
  29
  30
  31 (* Hack to sleep less than 1 sec *)
  32 let minisleep subsec =
  33   ignore (Unix.select [] [] [] subsec)
  34
  35
  36 let init_board x y =
  37   Array.map (Array.map (fun _ -> Random.int 2)) (Array.make_matrix y x 0)
  38
  39
  40 let print_board board =
  41   Array.iter
  42   (fun row ->
  43     Array.iter
  44     (fun state -> print_char (char_of_state state))
  45     row;
  46     print_newline ()
  47   )
  48   board
  49
  50
  51 let new_state = function
  52   | 1, live_neighbors when live_neighbors < 2 -> 0
  53   | 1, live_neighbors when live_neighbors < 4 -> 1
  54   | 1, live_neighbors when live_neighbors > 3 -> 0
  55   | 0, live_neighbors when live_neighbors = 3 -> 1
  56   | state, _ -> state
  57
  58
  59 let filter_offsides width height neighbors =
  60   List.filter
  61   (fun (x, y) -> x >= 0 && y >= 0 && x < width && y < height)
  62   neighbors
  63
  64
  65 let new_generation board =
  66   let height = Array.length board
  67   and width = Array.length board.(0) in
  68   Array.mapi
  69   (
  70     fun i_y row ->
  71       Array.mapi
  72       (fun i_x state->
  73         let neighbors =
  74           List.map
  75           (fun d ->
  76             let off_x, off_y = offset d in
  77             (i_x + off_x), (i_y + off_y)
  78           )
  79           directions
  80         in
  81         let neighbors = filter_offsides width height neighbors in
  82         let states = List.map (fun (x, y) -> board.(y).(x)) neighbors in
  83         let live_neighbors = List.fold_left (+) 0 states in
  84         let state = new_state (state, live_neighbors) in
  85         state
  86       )
  87       row
  88   )
  89   board
  90
  91
  92 let rec life_loop board =
  93   print_board board;
  94   print_newline ();
  95   minisleep 0.1;
  96   life_loop (new_generation board)
  97
  98
  99 let main argv =
 100   let x = int_of_string argv.(1)
 101   and y = int_of_string argv.(2)
 102   in
 103
 104   Random.init (int_of_float (Unix.time ()));
 105
 106   life_loop (init_board x y)
 107
 108
 109 let () = main Sys.argv