let deriver = "eq"

   let main () =
     let out = ref "" in
     let args =
       [ ("-o", Arg.Set_string out, "")
       ; ("--impl", Arg.Set_string (ref ""), "")
       ; ("--as-ppx", Arg.Set (ref false), "")
       ; ("--cookie", Arg.Set (ref false), "")
       ]
     in
     let anon _ = () in
     Arg.parse (Arg.align args) anon "";
     let out = open_out !out in
     close_out out;
