lec 06 modules???

lecture06/bstree2.ml

@@ -0,0 +1,68 @@
+(* dont do this *)
+
+
+module Bstree = struct
+type 'a t = Leaf | Node of 'a * 'a t * 'a t;;
+
+let rec size t =
+  match t with
+  | Leaf -> 0
+  | Node (_, l, r) ->
+    1 + size l + size r;;
+
+let rec height t =
+  match t with
+  | Leaf -> 0
+  | Node (_, l, r) ->
+    1 + max (height l) (height r);;
+
+let empty = Leaf;;
+
+let is_empty t = t = Leaf;;
+
+let rec insert x t =
+  match t with
+  | Leaf -> Node (x, Leaf, Leaf)
+  | Node (x', l, r) when x < x' ->
+    Node (x', insert x l, r)
+  | Node (x', l, r) when x > x' ->
+    Node (x', l, insert x r)
+  | _ -> t;;
+
+let of_list l =
+  List.fold_left (Fun.flip insert) Leaf l;;
+
+let rec mem x t =
+  match t with
+  | Leaf -> false
+  | Node (x', l, _) when x < x' ->
+    mem x l
+  | Node (x', _, r) when x > x' ->
+    mem x r
+  | _ -> true;;
+
+let rec largest t =
+  match t with
+  | Leaf -> failwith "largest: empty tree"
+  | Node (x, _, Leaf) -> x
+  | Node (_, _, r) -> largest r;;
+
+let rec smallest t =
+  match t with
+  | Leaf -> failwith "smallest: empty tree"
+  | Node (x, Leaf, _) -> x
+  | Node (_, l, _) -> smallest l;;
+
+let rec delete x t =
+  match t with
+  | Leaf -> Leaf
+  | Node (x', l, r) when x < x' ->
+    Node (x', delete x l, r)
+  | Node (x', l, r) when x > x' ->
+    Node (x', l, delete x r)
+  | Node (_, l, Leaf) -> l
+  | Node (_, Leaf, r) -> r
+  | Node (_, l, r) ->
+    let succ = largest l in
+    Node (succ, delete succ l, r);;
+end