convert (Erubis::Converter)

    # File lib/erubis/converter.rb, line 33
        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