Always wrap instance variables in accessor methods instead of directly
referring to variables…

这是一个例子,我已经解释过了：

class Gear
  attr_reader :chainring,:cog
  ...
  def ratio
    # this is bad
    # @chainring / @cog.to_f
    # this is good
    chainring / cog.to_f
end

我看到使用实例变量创建新对象的最常见方式是：

class Book
  attr_accessor :title
  def initialize(title)
    @title = title
  end
end

@ title =直接访问实例变量title.假设我们遵循’属性超过实例变量’约定,是否更适合使用self.title =,which would tell the object to send itself the message title=,从而使用属性write方法直接对实例变量？

class Book
  attr_accessor :title
  def initialize(title)
    self.title = title
  end
end

本书讨论了“实例变量的属性”,并参考了读取实例变量,但它是否也适用于写作？