signature SIMPLE_IO = sig
       type instream
       type outstream
       type vector
       val openIn: string-> instream
       val closeIn: instream -> unit
       val openOut: string-> outstream
       val closeOut: outstream -> unit
       val inputAll: instream -> vector
       val output: outstream * vector -> unit
    end

functor ManagedIO(SimpleIO:SIMPLE_IO) = struct

    val inputAll = SimpleIO.inputAll
    val output = SimpleIO.output
              
    fun withInputFile fname manage = let
        val file = SimpleIO.openIn fname
    in     
         manage file 
         finally SimpleIO.closeIn file
    end

    fun withOutputFile fname manage = let
        val file = SimpleIO.openOut fname
    in     
         manage file 
         finally SimpleIO.closeOut file
    end
end