P.J. Eby wrote:
(I'm thus finding it hard to believe there's a non-contrived example that's not doing I/O, scheduling, or some other form of co-operative multitasking.)
Have you seen my xml parser example? http://www.cosc.canterbury.ac.nz/greg.ewing/python/yield-from/ Whether you'll consider it contrived or not I don't know (contrivedness being such a subjective property) but it illustrates the style of programming I'm trying to support with the return-value feature.
In any case, you didn't address the confusion issue: the inability of generators to return a value is there for a good reason,
It's there because formerly there was nowhere for the return value to go. If there is somewhere for it to go, the restriction will no longer be needed. Things like this have happened before. It used to be forbidden to put a yield in a try-finally block, because there was no way to ensure that the finally would be executed. Once a way was found to do that, the restriction was lifted. As for confusion, we ignore the return values of function calls all the time, without worrying that someone might be confused by the fact that their return value doesn't go anywhere. And that's the right way to think of a yield-from expression -- as a kind of function call, not a kind of yield. If there's anything confusing, it's the presence of the word 'yield'. Its only virtue is that it gives a clue that the construct has something to do with generators, but you'll have to RTM to find out exactly what. Nobody has thus far suggested any better name, however. -- Greg _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
