 
   ## Example
 
-     tuple = { :foo, :bar, 3 }
-     elem(tuple, 1) #=> :bar
+      tuple = { :foo, :bar, 3 }
+      elem(tuple, 1) #=> :bar
 
   """
   defmacro elem(tuple, index) when is_integer(index) do


  ## Examples

    !1        #=> false
    ![1,2,3]  #=> false
    !false    #=> true
    !nil      #=> true

  """
  defmacro !arg


  ## Example

      tuple = { :foo, :bar, 3 }
      setelem(tuple, 0, :baz) #=> { :baz, :bar, 3 }

  """
  defmacro setelem(tuple, index, value) when is_integer(index) do
