I have two questions:
f_1 belong to the metaclass anonymous class?f_2 belong to the anonymous class?related to the following code:
car = "car"
class << car
def self.f_1
puts "f_1"
end
def f_2
puts "f_2"
end
end
Since ruby's own API uses the term "singleton class," I'd say the following are true:
f_1 is a class method on car's singleton class and can be called like this:
car.singleton_class.f_1
f_2 is an instance method on car's singleton class and can be called like this:
car.f_2
Well, terminology is frangible, but FWIW I would say your class wasn't really an anonymous class. As for belonging, both of these methods only exist in the car object.
I'll be honest and admit that I'm a little vague about the difference between a class method and an instance method when the class is defined against an individual object like this -- I would guess that if there is any difference, it will be an obscure one that will make your code much harder to read ;)
Update: You might find this helpful, if you've not seen it before. (Personally, it makes my head hurt, but everyone's different...)
I was under the impression that an anonymous class is a class that has no name:
my_class = Class.new
my_class.name # => nil
However, the Pickaxe refers to it as a unnamed class rather than as an anonymous class.
A reformulation of Rob Davis' answer:
:f_1 is car.singleton_class.singleton_class.:f_2 is car.singleton_class.The chain car → car.singleton_class → car.singleton_class.singleton_class corresponds to the bottom row in the diagram at http://www.atalon.cz/rb-om/ruby-object-model/#sc-inheritance-sample.
Notes:
