问灵丹妙药:如何使用一个列表作为变量定义多个宏？

EN

defmodule IEx.MyHelpers do

  def default_env do
    __ENV__
  end

  [:functions, :macros] |> Enum.each(fn name ->
    defmacro unquote(name)(option \\ :all) do
      import MapSet
      quote do
        case unquote(option) do
          x when x in [:a, :all]      -> __ENV__     |> Map.take([unquote(name)])
          x when x in [:d, :default]  -> default_env |> Map.take([unquote(name)])
          x when x in [:i, :imported] ->
            difference(new(Map.take(__ENV__, [unquote(name)])),
                       new(Map.take(default_env, [unquote(name)])))
            |> MapSet.to_list
        end
      end
    end
  end)

end