Guido> I expect that most iterator comprehensions (we need a better Guido> term!) You didn't like "lazy list comprehensions"? Guido> We can quibble about whether double parentheses are needed, ... You haven't convinced me that you're not going to want to toss out one of the two comprehension syntaxes and only retain the lazy semantics in Py3k. If that's the case and the current list comprehension syntax is better than the current crop of proposals, why even add (lazy list|iterator) comprehensions now? Just make do without them until Py3k and make all list comprehensions lazy at that point. There will be enough other bullets to bite that this shouldn't be a big deal (many programs will probably require significant rewriting anyway). Skip