nth2.re

let rec nth l n =>
  switch l {
  | [] => None
  | [h, ...t] => n === 0 ? Some h : nth t (n - 1)
  };

let x = nth [0, 1, 2, 3] 999; /* option int: None */

switch x {
| Some i => print_int i
| None => print_string "not found!"
};

let y = nth [0, 1, 2, 3] 1; /* option int: Some 1 */

switch y {
| Some i => print_int i
| None => print_string "not found!"
};