class FileWriter
  def initialize()
    self.lines = []
    self.current_line = ''
  end

  defm set_output_file(output_file)
    self.output_file = output_file
  end

  defm write(line)
    self.current_line = "#{self.current_line}#{line}"
  end

  defm writeln(line)
    self.flush_line()
    add(self.lines, line)
  end

  defm flush_line()
    unless self.current_line == ''
      add(self.lines, self.current_line)
      self.current_line = ''
    end
  end

  defm flush()
    self.flush_line()
    writefile(self.lines, self.output_file)
  end
end