class WriterFactory
  defm get_writer(writer_name)
    if a:writer_name == 'file'
      return new FileWriter()
    elseif a:writer_name == 'console'
      return new ConsoleWriter()
    elseif a:writer_name == 'buffer'
      return new BufferWriter()
    else
      return new BufferWriter()
    end
  end
end