attr_accessor 如何在 Ruby on Rails 中工作 [英] How does attr_accessor work in Ruby on Rails

问题描述

可能的重复:
Ruby 中的 attr_accessor 是什么?

示例代码如下:

class User
  attr_accessor :name, :email

  def initialize(attributes = {})
    @name = attributes[:name]
    @email = attributes[:email] 
  end 

....

end

当我这样做

example = User.new

它创建了一个空用户，我可以通过

it creates an empty user and I can assign its name and email by

example.name = "something"
example.email = "something" 

我的问题是，为什么这个东西有效?计算机如何知道example.name 表示类中的@name 变量?我假设 name 和 :name 是不同的，在代码中我们没有明确告诉计算机 example.name 等同于 :name 符号.

My question is, why this thing works? How does the computer know that example.name means the @name variable in the class? I'm assuming name and :name are different, and here in the code we have not explicitly told the computer that example.name is equivalent to :name symbol.

推荐答案

attr_accessor :field 与调用 attr_reader :field 和 attr_writer :field<相同/代码>.那些又大致等于:

attr_accessor :field is the same as calling attr_reader :field and attr_writer :field. Those in turn are roughly the equal to:

def field
  @field
end

def field=(value)
  @field = value
end

欢迎使用元编程的魔力.;)

Welcome to the magic of meta-programming. ;)

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