rough draft, need to remove arrays

life.ml

@@ -0,0 +1,117 @@
+let h = 45
+let w = 75
+
+let (|>) x f = f x
+
+let range n =
+  let rec loop n =
+    if n < 0 then
+      []
+    else
+      n :: (loop (n - 1))
+  in
+  loop (n - 1)
+
+
+let mkboard () =
+  Array.init h (fun _ ->
+    Array.init w (fun _ ->
+      0))
+
+let get board (r, c) =
+  Array.get (Array.get board r) c
+
+let set board (r, c) s =
+  Array.set (Array.get board r) c s
+
+let print board =
+  List.iter
+    (fun r ->
+       List.iter
+         (fun c ->
+           if get board (r, c) = 0 then
+             print_string " "
+           else
+             print_string "o")
+         (range w);
+       print_string "\n")
+    (range h)
+
+let neighbors (r, c) =
+  let up = (r + h - 1) mod h in
+  let dn = (r +     1) mod h in
+  let lt = (c + w - 1) mod w in
+  let rt = (c +     1) mod w in
+  [ (up, lt); (up, c); (up, rt)
+  ; (r,  lt);          (r,  rt)
+  ; (dn, lt); (dn, c); (dn, rt)
+  ]
+
+let live_neighbors board coords =
+  coords
+    |> neighbors
+    |> List.map (get board) 
+    |> List.fold_left (+) 0
+
+let step board =
+  let nb = mkboard () in
+  List.iter
+    (fun r ->
+      List.iter
+        (fun c ->
+          let ln = live_neighbors board (r, c) in
+          if 2 < ln && ln < 5 then
+            set nb (r, c) 1
+          else
+            set nb (r, c) 0)
+        (range w))
+    (range h);
+  nb
+
+let sleep () =
+  let rec loop n =
+    if n <= 0 then
+      ()
+    else begin
+      loop (n - 1);
+      loop (n - 1)
+    end
+  in
+  loop 22
+
+
+let clear () =
+  List.iter
+    (fun _ -> print_endline "")
+    (range 80)
+
+let rec loop b =
+  let b' = step b in
+  clear ();
+  print b;
+  flush stdout;
+  sleep ();
+  loop b'
+
+
+let b = mkboard ()
+
+let _ =
+  List.iter
+    (fun (r, c) -> set b (r, c) 1)
+    [ (1, 1)
+    ; (1, 3)
+    ; (2, 2)
+    ; (2, 3)
+    ; (3, 2)
+    ; (3, 3)
+    ; (3, 1)
+    ; (5, 6)
+    ; (5, 5)
+    ; (5, 7)
+    ; (5, 8)
+    ; (6, 5)
+    ]
+
+let _ = loop b
+