progress bar write in Ocaml

progress.ml

;;
#load "unix.cma"

let rec repeat str n =
  match n with 0 -> str | 1 -> str | n -> str ^ repeat str (n - 1)

let () =
  let sum = ref 1 in
  while true do
    Printf.printf "[%d%%]%s" !sum (repeat "#" !sum);
    flush stdout;
    Unix.sleepf 0.03;
    Printf.printf "%s" "\r";
    Printf.printf "%s" (repeat " " 110);
    Printf.printf "%s" "\r";
    flush stdout;
    if !sum == 100 then sum := 0;
    sum := !sum + 1
  done

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