Option Type

The Option Type

OCaml uses option to represent values that might be absent — no null pointers!

type 'a option = None | Some of 'a

A value is either Some x (present) or None (absent).

Pattern Matching on Options

let describe opt =
  match opt with
  | None -> "nothing"
  | Some x -> "got: " ^ string_of_int x

Safe Operations

Options are perfect for operations that might fail. You can use match to safely extract values:

let get_or_default opt d =
  match opt with
  | None -> d
  | Some x -> x

Your Task

Write a function find_positive that takes a list and returns the first positive number as a string, or "none" if no positive number exists. Use a helper show_option to convert the result.