Nested Macro

gistfile1.ex

defmodule Example do

  defmacro __using__(_options) do
    quote do
      Module.register_attribute __MODULE__, :attr, accumulate: true, persist: false
      import unquote(__MODULE__)
    end
  end

  defmacro append(attr) do
    quote do
      @attr unquote(attr)
    end
  end

  defmacro append_twice(attr) do
    quote do
      append unquote(attr)
      append unquote(attr)
    end
  end
end


defmodule UseExample do
  use Example

  append :foo
  append_twice :foo
end