examples/gcd/jsmain.ml

   1
   2
   3 (* computation part  *)
   4
   5 let compute_result text =
   6   try
   7     let a,b = Scanf.sscanf text "%d %d" (fun x y -> x,y) in
   8     string_of_int (EuclideanAlgorithm63.euclid a b)
   9   with _ -> "exception"
  10
  11
  12
  13 (* HTML rendering *)
  14
  15 module Html = Js_of_ocaml.Dom_html
  16 module Js = Js_of_ocaml.Js
  17 module Dom = Js_of_ocaml.Dom
  18
  19 let node x = (x : #Dom.node Js.t :> Dom.node Js.t)
  20
  21 let (<|) e l = List.iter (fun c -> Dom.appendChild e c) l; node e
  22
  23 let html_of_string (d : Html.document Js.t) (s:string) =
  24   d##createElement (Js.string "p") <|
  25       [node (d##createTextNode (Js.string s))]
  26
  27 let replace_child p n =
  28   Js.Opt.iter (p##.firstChild) (fun c -> Dom.removeChild p c);
  29   Dom.appendChild p n
  30
  31 let onload (_event : #Html.event Js.t) : bool Js.t =
  32   let d = Html.document in
  33   let body =
  34     Js.Opt.get (d##getElementById(Js.string "test"))
  35       (fun () -> assert false) in
  36   let textbox = Html.createTextarea d in
  37   textbox##.rows := 20; textbox##.cols := 100;
  38   let preview = Html.createDiv d in
  39   preview##.style##.border := Js.string "1px black";
  40   preview##.style##.padding := Js.string "5px";
  41   Dom.appendChild body textbox;
  42   Dom.appendChild body (Html.createBr d);
  43   Dom.appendChild body preview;
  44   let rec dyn_preview old_text n =
  45     let text = Js.to_string (textbox##.value) in
  46     let n =
  47       if text <> old_text then
  48         begin
  49           begin try
  50                   let rendered =
  51                     html_of_string d (compute_result text)
  52                   in
  53                   replace_child preview rendered
  54             with _ -> ()
  55           end;
  56           20
  57         end
  58       else
  59         max 0 (n - 1)
  60     in
  61     Lwt.bind
  62       (Js_of_ocaml_lwt.Lwt_js.sleep (if n = 0 then 0.5 else 0.1))
  63       (fun () -> dyn_preview text n)
  64   in
  65   let (_ : 'a Lwt.t) = dyn_preview "" 0 in Js._false
  66
  67 let (_ : unit) = Html.window##.onload := Html.handler onload