Use point abstraction.

[cellular-automata.git] / polymorphic-life / 001 / src / polymorphic_life.ml

diff --git a/polymorphic-life/001/src/polymorphic_life.ml b/polymorphic-life/001/src/polymorphic_life.ml
index 1afd1fe..a5e39c0 100644 (file)
--- a/polymorphic-life/001/src/polymorphic_life.ml
+++ b/polymorphic-life/001/src/polymorphic_life.ml
@@ -2,22 +2,58 @@ open Core.Std
 
 
 module type MATRIX = sig
+  module Point : sig
+    type t = {r : int; k : int}
+  end
+
   type 'a t
 
   val create : rs:int -> ks:int -> data:'a -> 'a t
 
-  val get : 'a t -> r:int -> k:int -> 'a
+  val get_neighbors : 'a t -> Point.t -> 'a list
 
   val map : 'a t -> f:('a -> 'b) -> 'b t
 
-  val mapi : 'a t -> f:(r:int -> k:int -> data:'a -> 'b) -> 'b t
+  val mapi : 'a t -> f:(Point.t -> data:'a -> 'b) -> 'b t
 
-  val iter : 'a t -> f:(r:int -> k:int -> data:'a -> unit) -> unit
+  val iter : 'a t -> f:(Point.t -> data:'a -> unit) -> unit
 
   val print : 'a t -> to_string:('a -> string) -> unit
 end
 
 module Matrix : MATRIX = struct
+  module Point = struct
+    type t = {r : int; k : int}
+
+    let (+) p p' =
+      { r = p.r + p'.r
+      ; k = p.k + p'.k
+      }
+  end
+
+  module Direction = struct
+    type t = NW | N | NE
+           | W  |     E
+           | SW | S | SE
+
+    let all = [ NW ; N ; NE
+              ; W  ;     E
+              ; SW ; S ; SE
+              ]
+
+    let to_offset =
+      let open Point in
+      function
+      | NW -> {r = -1; k = -1}
+      | N  -> {r = -1; k =  0}
+      | NE -> {r = -1; k =  1}
+      | W  -> {r =  0; k = -1}
+      | E  -> {r =  0; k =  1}
+      | SW -> {r =  1; k = -1}
+      | S  -> {r =  1; k =  0}
+      | SE -> {r =  1; k =  1}
+  end
+
   type 'a t = 'a array array
 
   let create ~rs ~ks ~data =
@@ -28,7 +64,7 @@ module Matrix : MATRIX = struct
       fun r ks ->
         Array.iteri ks ~f:(
           fun k data ->
-            f ~r ~k ~data
+            f {Point.r; Point.k} ~data
         )
     )
 
@@ -47,12 +83,27 @@ module Matrix : MATRIX = struct
       fun r ks ->
         Array.mapi ks ~f:(
           fun k data ->
-            f ~r ~k ~data
+            f {Point.r; Point.k} ~data
         )
     )
 
-  let get t ~r ~k =
+  let get t {Point.r; Point.k} =
     t.(r).(k)
+
+  let is_within_bounds t {Point.r; Point.k} =
+    match t with
+    | [||] -> assert false
+    | t ->
+      r >= 0 && r < Array.length t &&
+      k >= 0 && k < Array.length t.(0)
+
+  let neighborhood t point =
+    List.map Direction.all ~f:Direction.to_offset
+    |> List.map ~f:(fun offset_point -> Point.(point + offset_point))
+    |> List.filter ~f:(is_within_bounds t)
+
+  let get_neighbors t point =
+    List.map (neighborhood t point) ~f:(get t)
 end
 
 
@@ -105,6 +156,14 @@ end
 let main rs ks () =
   Random.self_init ();
   let grid = Matrix.create ~rs ~ks ~data:() |> Matrix.map ~f:Conway.create in
+  Matrix.print grid ~to_string:Conway.to_string;
+  print_endline (String.make 80 '-');
+  let grid =
+    Matrix.mapi grid ~f:(fun point ~data:cell ->
+      let neighbors = Matrix.get_neighbors grid point in
+      Conway.react cell ~states:(List.map neighbors ~f:Conway.state)
+    )
+  in
   Matrix.print grid ~to_string:Conway.to_string