X-Git-Url: https://git.xandkar.net/?p=tiger.ml.git;a=blobdiff_plain;f=exercises%2Fch01%2Ftree.ml;h=6b0ab435bc9045d063dc391e54803b62e29305e2;hp=7cc7d8cc4bcf92eea8610d8f3ae20ea5f4ed92a0;hb=8dd2823829e0b265bd01002a3d6eba0897d7885e;hpb=f76c63f8cff09c1de6619d49e0a761e3bb6c8618

diff --git a/exercises/ch01/tree.ml b/exercises/ch01/tree.ml
index 7cc7d8c..6b0ab43 100644
--- a/exercises/ch01/tree.ml
+++ b/exercises/ch01/tree.ml
@@ -1,42 +1,58 @@
 module Array = ArrayLabels
 
 module type TREE = sig
-  type 'a t
+  type ('k, 'v) t
 
-  val empty : 'a t
+  val empty : ('k, 'v) t
 
-  val add : 'a t -> 'a -> 'a t
+  val set : ('k, 'v) t -> k:'k -> v:'v -> ('k, 'v) t
 
-  val member : 'a t -> 'a -> bool
+  val get : ('k, 'v) t -> k:'k -> 'v option
+
+  val member : ('k, 'v) t -> k:'k -> bool
 end
 
 module BinaryTree : TREE = struct
-  type 'a t =
-    | Node of 'a * 'a t * 'a t
+  type ('k, 'v) t =
+    | Node of 'k * 'v * ('k, 'v) t * ('k, 'v) t
     | Leaf
 
   let empty = Leaf
 
-  let rec add t x =
+  let rec set t ~k ~v =
+    match t with
+    | Leaf -> Node (k, v, Leaf, Leaf)
+    | Node (k', v', l, r) when k < k' -> Node (k', v', set l ~k ~v, r)
+    | Node (k', v', l, r) when k > k' -> Node (k', v', l, set r ~k ~v)
+    | Node (k, _, l, r) -> Node (k, v, l, r)
+
+  let rec get t ~k =
     match t with
-    | Leaf -> Node (x, Leaf, Leaf)
-    | Node (x', left, right) when x < x' -> Node (x', add left x, right)
-    | Node (x', left, right) when x > x' -> Node (x', left, add right x)
-    | (Node _) as t' -> t'
+    | Leaf -> None
+    | Node (k', _, l, _) when k < k' -> get l ~k
+    | Node (k', _, _, r) when k > k' -> get r ~k
+    | Node (_, v, _, _) -> Some v
 
-  let rec member t x =
+  let rec member t ~k =
     match t with
     | Leaf -> false
-    | Node (x', left, _) when x < x' -> member left x
-    | Node (x', _, right) when x > x' -> member right x
+    | Node (k', _, l, _) when k < k' -> member l ~k
+    | Node (k', _, _, r) when k > k' -> member r ~k
     | Node _ -> true
 end
 
 let () =
-  let tree =
+  let tree_a = BinaryTree.empty in
+  let tree_a = BinaryTree.set tree_a ~k:"k1" ~v:"v1" in
+  let tree_a = BinaryTree.set tree_a ~k:"k2" ~v:"v2" in
+  assert (BinaryTree.member tree_a ~k:"k1");
+  assert (BinaryTree.member tree_a ~k:"k2");
+  assert (Some "v1" = BinaryTree.get tree_a ~k:"k1");
+  assert (Some "v2" = BinaryTree.get tree_a ~k:"k2");
+  let tree_b =
     Array.fold_left
       (Sys.argv)
       ~init:BinaryTree.empty
-      ~f:(fun t str -> BinaryTree.add t str)
+      ~f:(fun t k -> BinaryTree.set t ~k ~v:())
   in
-  Printf.printf "%B\n" (BinaryTree.member tree "a")
+  Printf.printf "%B\n" (BinaryTree.member tree_b ~k:"a")