是否可以比较 Ruby 中的私有属性? [英] Is it possible to compare private attributes in Ruby?

问题描述

我正在考虑:

class X
    def new()
        @a = 1
    end
    def m( other ) 
         @a == other.@a
    end
end

x = X.new()
y = X.new()
x.m( y ) 

但它不起作用.

错误信息是:

syntax error, unexpected tIVAR

那么我如何比较同一类的两个私有属性呢?

How can I compare two private attributes from the same class then?

推荐答案

有几种方法

吸气剂:

class X
  attr_reader :a
  def m( other )
    a == other.a
  end
end

instance_eval:

class X
  def m( other )
    @a == other.instance_eval { @a }
  end
end

instance_variable_get:

class X
  def m( other )
    @a == other.instance_variable_get :@a
  end
end

我不认为 ruby​​ 有朋友"或受保护"访问的概念，甚至私人"也很容易被黑掉.使用getter创建一个只读属性，instance_eval意味着你必须知道实例变量的名字，所以内涵类似.

I don't think ruby has a concept of "friend" or "protected" access, and even "private" is easily hacked around. Using a getter creates a read-only property, and instance_eval means you have to know the name of the instance variable, so the connotation is similar.

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