如何捕获ocaml顶层的js\u标准输出

我有一个js\uOcaml代码,它接受一个字符串并执行它(假设字符串是ocaml代码):

let () = JsooTop.initialize ()

let execute code =
  let code = Js.to_string code in
  let buffer = Buffer.create 100 in
  let formatter = Format.formatter_of_buffer buffer in
  JsooTop.execute true formatter code;
  Js.string (Buffer.contents buffer)

(* Usage: *)
let () =
    let ret_val_1 = execute "let x = 5;;" in
    let ret_val_2 = execute "print_int (x * x);;" in  (* 25 appears in the browser console. *)
    print_endline ret_val_1;  (* Prints: "val x : int = 5" *)
    print_endline ret_val_2   (* Prints: "- : unit = ()" *)

25 print_int (x * x) 线路。我想使用输出(即。 25 )而不是让它出现在浏览器控制台中。如何捕获由ocaml的js_打印函数生成的标准输出?i、 我怎样才能得到 25 在上面的代码里?