There's nothing wrong with this approach. (I certainly hope there isn't because my own code is filled with instances of this pattern.) But it has always annoyed me to saddle a function with a test that is useful only once in its lifetime. It's a perverse sense of aesthetics, I admit it, but that is, at any rate, the motivation behind the gyrations... I was just wondering whether there were fundamental problems with the approach (other than its neurotic convolutedness).