Terry Reedy wrote:

So, are things like this a programming bug, interpreter bug, or language definition bug? or just a 'gotcha'?

Gotcha. In pretty much every language, you have to be careful about modifying what you're iterating over. I don't see that Python should be any different ;) However, Tim's example is a bit less obvious that you are modifying the thing you're iterating over ... Hence the "cuteness" IMO. Tim Delaney