signature CPP = sig
  structure T: TOKENIZER

  type t
  type tkPos

  type tkExpectedVal
  exception TkExpected of tkExpectedVal

  type tkErrorVal
  exception TkError of tkErrorVal

  datatype tkExp =
    Tk of T.token |
    Id |
    NumConst |
    StrLiteral |
    UnOp |
    BinOp |
    Op

  val create: string -> string list -> t
  val getToken: t -> T.token * t
  val getLastPos: t -> tkPos

  val tkExpectedPrint: tkExpectedVal -> unit
  val tkErrorPrint: tkErrorVal -> unit

  val debugPrint: t -> unit
end