basics_Lwt_Term_simple_terminal_timeout.ml

(* ocamlfind ocamlc -o double_threads -package lwt,notty.lwt -linkpkg -g double_threads.ml*)
open Lwt
open Lwt.Infix
open Notty
open Notty_lwt
open Notty.Infix

module Term = Notty_lwt.Term

let counter = ref 0

let rec increase_counter () =
  Lwt_unix.sleep 0.1
  >>= fun () ->
    (
    if !counter < max_int then counter := (!counter + 1)
    else counter := 0
  );
  Lwt.return ()
  >>= fun () ->
    increase_counter ()

let render (w, h) =
  I.(strf ~attr:A.(fg lightblack) "[counter %d]" !counter)

let timer () = Lwt_unix.sleep 0.1 >|= fun () -> `Timer

let event term = Lwt_stream.get (Term.events term) >|= function
  | Some (`Resize _ | #Unescape.event as x) -> x
  | None -> `End

let rec loop term (e, t) dim =
  (e <?> t) >>= function
  | `End | `Key (`Escape, []) ->
      Lwt.return_unit
  | `Timer ->
      Term.image term (render dim)
      >>= fun () ->
        loop term (e, timer ()) dim
  | `Mouse ((`Press _|`Drag), (x, y), _) ->
      loop term (event term, t) dim
  | `Resize dim ->
      Term.image term (render dim)
      >>= fun () ->
        loop term (event term, t) dim
  | _ -> loop term (event term, t) dim

let interface () =
  let tc = Unix.(tcgetattr stdin) in
  Unix.(tcsetattr stdin TCSANOW { tc with c_isig = false });
  let term    = Term.create () in
  let size = Term.size term in
  loop term (event term, timer ()) size

let main () =
  Lwt.choose [
    increase_counter ();
    interface ();
  ]

let () = Lwt_main.run (main ())