gistfile1.rbx

class Foo
  def self.inherited klass
    klass.send :class_variable_set, :@@attribute_initializations, []
    klass.send :define_method, :bar do
      self.class.send :class_variable_get, :@@attribute_initializations
    end
  end
end

class A < Foo
  @@attribute_initializations << :a
  p @@attribute_initializations
end

class B < Foo
  @@attribute_initializations << :b
  p @@attribute_initializations
end

p A.new.bar
p B.new.bar