Add toplevel loading script

toplevel/dune

@@ -0,0 +1,24 @@
+let run_and_get_lines cmd =
+  let inp = Unix.open_process_in cmd in
+  let res = ref [] in
+  let () = try
+    while true do
+      let line = input_line inp in
+      res := List.cons line !res
+    done
+  with End_of_file ->
+    close_in inp
+  in
+  List.rev(!res)
+in
+let exec s =
+  let l = Lexing.from_string s in
+  let ph = !Toploop.parse_toplevel_phrase l in
+  let fmt = Format.make_formatter (fun _ _ _ -> ()) (fun _ -> ()) in
+  try
+    let _ = Toploop.execute_phrase false fmt ph in ()
+  with
+      _ -> ()
+in
+let lines = run_and_get_lines "./dune.exe toplevel-init-file" in
+List.iter (fun l -> exec l) lines