gistfile1.ex

defmodule A do
  defmacro __before_compile__(_env) do
      funs = Enum.map([:a, :b], fn(name) ->
          quote do
            def unquote(name)(), do: unquote(name)
          end
      end)

      quote do
        unquote_splicing(funs)
      end
  end
end

defmodule B do
  @before_compile A
end