ruby - 如何在 Ruby 中为类变量编写编写器方法？

Question

我正在研究 Ruby，我的大脑突然卡住了。

在下面的代码中，我将如何编写“self.total_people”的类编写器方法？我正在尝试“计算”类“Person”的实例数。

    class Person

     attr_accessor :name, :age

 @@nationalities = ['French', 'American', 'Colombian', 'Japanese', 'Russian', 'Peruvian']

 @@current_people = []

 @@total_people = 0

def self.nationalities #reader
   @@nationalities
 end

 def self.nationalities=(array=[]) #writer
   @@nationalities = array
 end

 def self.current_people #reader
   @@current_people
 end

 def self.total_people #reader
   @@total_people
 end

def self.total_people #writer
  #-----?????
end



 def self.create_with_attributes(name, age)
   person = self.new(name)
   person.age = age
   person.name = name
   return person
 end


 def initialize(name="Bob", age=0)
   @name = name
   @age = age
   puts "A new person has been instantiated."
   @@total_people =+ 1
   @@current_people << self
 end

Answer 1

您可以通过将等号附加到方法名称的末尾来定义一个:

def self.total_people=(v)
  @@total_people = v
end

您将所有实例都放在@@current_people 中，您可以更准确地定义 total_people:

def self.total_people
  @@current_people.length
end

并删除所有与@@total_people 相关的代码。