Guido van Rossum
[snip]
Have you got a use case for membership tests of a cartesian product?
Not that I can think of at the moment, no :-) I guess the idea was to use lazy sets for some such operations. Then you could build complex expressions through cartesian products, unions, intersections, set differences, set comprehensions etc. without actually constructing the full set. Checking for membership or iterating over (or even constructing, after all the operations have been applied) such a set might be useful, I'm sure... You could implement joins with cartesian products without terrible performance penalties etc... But I guess this sort of thing might as well go into some other module somewhere (probably outside the libs). It was just a thought. -- Magnus Lie Hetland The Anygui Project http://hetland.org http://anygui.org