funclang taddeus series 3: prettified nth function.

funclang-taddeus/series3/ass7.ml

@@ -2,10 +2,9 @@ open List
 
 (* 1 *)
 let rec nth l n =
-    match n with
-    | 0 -> hd l
-    | i when i > 0 && i < (length l) -> nth (tl l) (i - 1)
-    | _ -> raise (Failure "list index out of bounds")
+    match l with
+    | [] -> raise (Failure "list index out of bounds")
+    | h::t -> if n = 0 then h else nth t (n - 1)
 ;;
 
 (* 2 *)