gistfile1.ex

  for event <- [:before_save, :before_update, :before_delete] do
    defmacro unquote(event)(function) do
      quote bind_quoted: [event: event] do
        Ecto.Model.Callbacks.register_callback(__MODULE__, event, unquote(function))
        def __callbacks__(:before_save), do: Keyword.get_values(@ecto_callbacks, :before_save)
      end
    end
  end

  for event <- [:before_save, :before_update, :before_delete] do
    defmacro unquote(event)(function) do
      event = unquote(event)
      quote unquote: true, bind_quoted: [event: event] do
        Ecto.Model.Callbacks.register_callback(__MODULE__, event, unquote(function))
        def __callbacks__(:before_save), do: Keyword.get_values(@ecto_callbacks, :before_save)
      end
    end
  end