Ruby Koans: explicit scoping on a class definition part 2

Question

I wanted to clarify some things off of this original post. The answer suggested that Ruby searches for the constant definition in this order:

1. The enclosing sco

Answer 1

I was just pondering the very same question from the very same koan. I am no expert at scoping, but the following simple explanation made a lot of sense to me, and maybe it will help you as well.

When you define MyAnimals::Oyster you are still in the global scope, so ruby has no knowledge of the LEGS value set to 2 in MyAnimals because you never actually are in the scope of MyAnimals (a little counterintuitive).

However, things would be different if you were to define Oyster this way:

class MyAnimals
  class Oyster < Animal
    def legs_in_oyster
      LEGS # => 2
    end
  end
end

The difference is that in the code above, by the time you define Oyster, you have dropped into the scope of MyAnimals, so ruby knows that LEGS refers to MyAnimals::LEGS (2) and not Animal::LEGS (4).

FYI, I got this insight from the following URL (referenced in the question you linked to):

• https://groups.google.com/forum/#!topic/comp.lang.ruby/t5rtDNol3P8