On Friday 17 October 2003 08:57 pm, Skip Montanaro wrote: ...
Forgive my extreme density on this matter, but I don't understand what
(yield x for x in S)
is supposed to do. Is it supposed to return a generator function which I can assign to a variable (or pass to the builtin function sum() as in your example) and call later, or is it supposed to turn the current function into a generator function (so that each executed yield statement returns a value to the caller of the current function)?
Neither: it returns an iterator, _equivalent_ to the one that would be returned by _calling_ a generator such as def xxx(): for x in S: yield x like xxx() [the result of the CALL to xxx, as opposed to xxx itself], (yield: x for x in S) is not callable; rather, it's loopable-on.
you don't like lambda, I can't quite see why syntax this is all that appealing.
I don't really like the current state of lambda (and it will likely never get any better), I particularly don't like the use of the letter lambda for this idea (Church's work notwithstanding, even Paul Graham in his new lispoid language has chosen a more sensible keyword, 'func' I believe), but I like comprehensions AND iterators, and the use of the word yield in generators. I'm not quite sure what parallels you see between the two cases. Alex