Convert as csv to an html table

csv_to_html_table.ml

module String = struct
  include Astring.String

  let tail str = with_index_range ~first:1 ~last:(length str) str
end

let create_thead str =
  let rec loop acc_lst acc_str str =
    match String.head str with
    | Some ch when ch = ',' -> loop (acc_str :: acc_lst) "" (String.tail str)
    | Some ch ->
        loop acc_lst
          (String.append acc_str (String.of_char ch))
          (String.tail str)
    | None -> acc_lst
  in
  loop [] "" str |> fun str_lst ->
  List.map (fun s -> String.append "<th>" @@ String.append s "</th>") str_lst
  |> fun str_lst ->
  String.concat ~sep:"\n" str_lst |> fun str ->
  String.append "<thead>\n<tr>\n" @@ String.append str "\n</tr>\n</thead>"

let create_tbody str_lst =
  let create_row_body str =
    let rec loop acc_lst acc_str str =
      match String.head str with
      | Some ch when ch = ',' -> loop (acc_str :: acc_lst) "" (String.tail str)
      | Some ch ->
          loop acc_lst
            (String.append acc_str (String.of_char ch))
            (String.tail str)
      | None -> acc_lst
    in
    loop [] "" str |> fun str_lst ->
    List.map (fun s -> String.append "<td>" @@ String.append s "</td>") str_lst
    |> fun str_lst ->
    String.concat ~sep:"\n" str_lst |> fun str ->
    String.append "<tr>\n" @@ String.append str "\n</tr>"
  in
  List.map create_row_body str_lst |> fun str_lst ->
  String.concat ~sep:"\n" str_lst |> fun str ->
  String.append "\n<tbody>\n" @@ String.append str "\n</tobdy>"

let input () =
  let file_channel =
    Stdlib.open_in "/home/sk/learnOCaml/csv_to_html_table/example.csv"
  in
  let rec loop acc =
    match input_line file_channel with
    | exception End_of_file -> acc
    | x -> loop @@ (x :: acc)
  in
  loop []
  |> List.map (fun s -> String.filter (fun x -> x != '\"') s)
  |> List.rev

let _ =
  input () |> fun lst ->
  let column_header = create_thead @@ List.hd lst in
  let column_elements = create_tbody @@ List.tl lst in
  Printf.printf "%s%s\n" column_header column_elements

(* List.iter (fun s -> Printf.printf "%s" s) lst *)

example csv file that I use

car name,miles/gallon,cylinders,displacement,horsepower,weight,acceleration,model year,origin
"chevrolet chevelle malibu",18,8,307,130,3504,12,70,1
"buick skylark 320",15,8,350,165,3693,11.5,70,1
"plymouth satellite",18,8,318,150,3436,11,70,