(* here is a multi-line comment on one line *)

(*
    here is a multi-line comment on
    multiple lines
*)

let index =
    len
    |> float
    |> Operators.(*) 0.1      // (*) here is not comment
    |> Operators.(+) 1        // (+) here is not comment
    |> Operators.(-) len      // (-) here is not comment
;;