   end
 
   defp do_eval([], _context), do: nil
+
   defp do_eval({:for_exp, exp}, context) do
     {enumerable, exp} = Keyword.pop_first(exp, :field)
     {enumerable_value, exp} = Keyword.pop_first(exp, :field)

  @doc """
  Evaluate a tag and return the condition that succeeded or nil
  """
  @spec eval(any, Context.t) :: {iolist, Context.t}
  def eval(tag, context) do
    case do_eval(tag, context) do
      {text, context} -> {text, context}

    context = %{context | vars: Map.put(context.vars, field, Argument.get(argument, context))}
    {nil, context}
  end

  defp do_eval(:comment, _context), do: nil

  defp eval_elsif({:elsif_exp, elsif_exp}, context) do
