+let debug = ref false;;
+let indent = ref "";;
+let times = ref [];;
+let pp s =
+ if !debug then
+ prerr_endline (Printf.sprintf "%-20s" !indent ^ " " ^ Lazy.force s)
+;;
+let inside c =
+ if !debug then
+ begin
+ let time1 = Unix.gettimeofday () in
+ indent := !indent ^ String.make 1 c;
+ times := time1 :: !times;
+ prerr_endline ("{{{" ^ !indent ^ " ")
+ end
+;;
+let outside exc_opt =
+ if !debug then
+ begin
+ let time2 = Unix.gettimeofday () in
+ let time1 =
+ match !times with time1::tl -> times := tl; time1 | [] -> assert false in
+ prerr_endline ("}}} " ^ string_of_float (time2 -. time1));
+ (match exc_opt with
+ | Some e -> prerr_endline ("exception raised: " ^ Printexc.to_string e)
+ | None -> ());
+ try
+ indent := String.sub !indent 0 (String.length !indent -1)
+ with
+ Invalid_argument _ -> indent := "??"; ()
+ end
+;;
+