frogs.rb

class Kozmik
  def self.acts_as_frog(species)
    (@frog_list ||= []) << species
    #self.class.send :attr_accessor, :frog_list
    #
    # === OR ===
    #
    # class << self 
    #   attr_accessor :frog_list
    # end
    #
    # === OR ===
    #
    # self.class.class_eval do attr_accessor :frog_list; end
    #
    # ==========
  end
  
  def self.inherited(base)
    puts base
    puts self
    self.class.class_eval do
      attr_accessor :frog_list
    end
  end
end

class Toad < Kozmik
  acts_as_frog :bufo
  acts_as_frog :kermit
  #puts 'Toad the weg sproket'
end

class BullFrog < Kozmik
  acts_as_frog :tree
  acts_as_frog :riparian
  #puts 'Bull****'
end

def test_fun_with_metaclasses 
  assert_equal [:tree, :riparian], BullFrog.frog_list
  assert_equal [:bufo, :kermit], Toad.frog_list
end