How can a nested class access a method in the outer class in Ruby?

Question

def class A
  def a
    raise \"hi\" #can\'t be reached
  end

  class B
    def b
      a() #doesn\'t find method a.
    end
  end
end

I want to invok

Answer 1

Was a supposed to be a class method for class A?

class A
  def self.a
    raise "hi"
  end
  class B
    def b
      A::a 
    end
  end
end

A::B.new.b

If you want to keep it as an instance method, you'll obviously have call to it on an instance, like for example A.new.a.