First few lines of Ocaml...

fizzbuzz.ml

open Base
open Stdio

let fizzbuzz i =
  match (i % 3, i % 5) with
  | (0,0) -> "FizzBuzz"
  | (0,_) -> "Fizz"
  | (_,0) -> "Buzz"
  | _ -> Int.to_string i

let rec range_apply i n ~f =
  match i with
  | _ when i = n + 1 -> ()
  | _ -> f i;
    range_apply (i + 1) n ~f

let rec get_int () =
  printf "Max number: ";
  Out_channel.flush stdout;
  let line = In_channel.input_line In_channel.stdin in
  match line with
  | None -> get_int  ()
  | Some x -> try
      Int.of_string x 
    with
    | Failure _ -> get_int ()

let () =
  let max = get_int () in
  range_apply 1 max ~f:(fun x -> printf "%s\n" (fizzbuzz x))