def convert(input)
      codebuf = ""    # or []
      @preamble.nil? ? add_preamble(codebuf) : (@preamble && (codebuf << @preamble))
      convert_input(codebuf, input)
      @postamble.nil? ? add_postamble(codebuf) : (@postamble && (codebuf << @postamble))
      @_proc = nil    # clear cached proc object
      return codebuf  # or codebuf.join()
    end
def convert(input)
      codebuf = ""    # or []
      @preamble.nil? ? add_preamble(codebuf) : (@preamble && (codebuf << @preamble))
      convert_input(codebuf, input)
      @postamble.nil? ? add_postamble(codebuf) : (@postamble && (codebuf << @postamble))
      @_proc = nil    # clear cached proc object
      return codebuf  # or codebuf.join()
    end
convert input string into target language