Question

我正在编写一个Ruby类，并希望覆盖==方法。我想说的是：

class ReminderTimingInfo
   attr_reader :times, :frequencies #don't want these to exist

   def initialize(times, frequencies)
      @times, @frequencies = times, frequencies
   end

   ...

   def ==(other)
      @times == other.times and @frequencies == other.frequencies
   end
end

如果不同时公开查看时间和频率，我该怎么做？

关注：

class ReminderTimingInfo

  def initialize(times, frequencies)
    @date_times, @frequencies = times, frequencies
  end

  ...

  def ==(other)
    @date_times == other.times and @frequencies == other.frequencies
  end

  protected

  attr_reader :date_times, :frequencies
end

Answer 1

如果您将时间和频率访问者设置为受保护，那么它们只能从该类和后代的实例访问（这应该没问题，因为后代无论如何都可以访问实例变量，并且应该知道如何正确处理它）。

class ReminderTimingInfo

  # …

protected
  attr_reader :times, :frequencies

end

Answer 2

你可以做到

  def ==(other)
    @date_times == other.instance_eval{@date_times} and @frequencies == other.instance_eval{@frequencies}
  end

但不知怎的，我怀疑那是错过了重点！

制作一个equals方法，而无需公开私有字段

2 个答案: