test.ml

let one_dot_words (~string:str string) (~character:chr char) =
  
  let rec one_dot_words_aux (str : string) (chr : char) (pos : int) (acc : string list) : string list =
    let max = Bytes.length str in
    let tmp = Bytes.copy str in
    if pos = max then 
      acc 
    else 
      one_dot_words_aux str chr (pos + 1) ((Bytes.set tmp pos chr;tmp) :: acc ) in
      
  one_dot_words_aux str chr 0 []