decToHex =
    let
      intToHex = [
        "0" "1" "2" "3" "4" "5" "6" "7" "8" "9"
        "a" "b" "c" "d" "e" "f"
      ];
      toHex' = q: a:
        if q > 0
        then (toHex'
          (q / 16)
          ((elemAt intToHex (mod q 16)) + a))
        else a;
    in
      v: toHex' v "";