gistfile1.ru

class Dragon
    def test
      "test"
    end
end

d = Dragon.new
puts d.test # test

# 呼叫 super (1)
def d.test
  "super1 " + super
end
puts d.test # super1 test

# 呼叫 super (2)
d.instance_eval do
  def test
    "super2 " + super
  end
end
puts d.test # super2 test

# 呼叫 super (3)
metaclass = ( class << d; self; end )
metaclass.class_eval do
  def test
    "super3 " + super
  end
end
puts d.test # super3 test

# -----------------------------------------------------------

Dragon.class_eval do
  def test
    "blah"
  end
end
puts d.test # "super3 blah". Why?

Dragon.class_eval do
  def test
    super
  end
end
puts d.test # fails. Why?

# Because "Dragon.class_eval + def" overrides original Dragon instance method, not singleton method.