ruby - Add method to an instanced object

Question

obj = SomeObject.new

def obj.new_method
  "do some things"
end

puts obj.new_method
> "do some things"

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

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?

Answer 1

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