#lang sml
(*
 * (c) Andreas Rossberg 1999-2007
 *
 * Stamp generator.
 *)

signature STAMP =
sig
    eqtype stamp

    val stamp :		unit  -> stamp
    val toString :	stamp -> string

    val reset :		unit -> unit

    val compare :	stamp * stamp -> order
    val min :		stamp * stamp -> stamp
end