向实例对象添加方法 [英] Add method to an instanced object

问题描述

obj = SomeObject.new

def obj.new_method
  "do some things"
end

puts obj.new_method
> "do some things"

这行得通.但是，我需要在现有方法中做同样的事情:

This works ok. However, I need to do same thing inside an existing method:

def some_random_method
  def obj.new_method
    "do some things"
  end
end

也可以正常工作，但是在方法中包含方法看起来非常糟糕.问题是，有没有其他方法可以添加这样的方法?

Works ok as well, but having a method inside a method looks pretty horrible. The question is, is there any alternate way of adding such a method?

推荐答案

好久没问这个问题了.在 ruby​​ 1.9+ 中，有一种更好的方法可以使用 define_singleton_method，如下所示:

It's been a long time since I asked this. In ruby 1.9+, there's a better way of doing this by using define_singleton_method, as follows:

obj = SomeObject.new

obj.define_singleton_method(:new_method) do
  "do some things"
end

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