Tuplify Elixir problem

output.txt

$ elixir tuplify.exs 
Returned from macro:
def(tuplify_from_macro(x)) do
  {unquote(Macro.var(:x, nil))}
end
** (CompileError) tuplify.exs:21: function x/0 undefined
    (stdlib) lists.erl:1336: :lists.foreach/2
    tuplify.exs:14: (file)
    (elixir) lib/code.ex:307: Code.require_file/2
    
$ erl -version
Erlang (ASYNC_THREADS) (BEAM) emulator version 6.4.1

$ elixir -v
Elixir 1.0.4

tuplify.exs

defmodule M do
  defmacro def_tuplify do
    result = quote(unquote: false) do
      def tuplify_from_macro(x) do
        {unquote(Macro.var :x, nil)}
      end
    end
    IO.puts "Returned from macro:\n#{result |> Macro.to_string}"
    result
  end
end


defmodule A do
  require M

  def tuplify(x) do
    { unquote(Macro.var :x, nil) }
  end

  M.def_tuplify
end


IO.puts "testing results"
IO.inspect A.tuplify(:ok)
IO.inspect A.tuplify_from_macro(:ok)