>> But, indexing does stretch quite far in the current Python syntax and >> semantics (in Python's *pragmatics* you're supposed to use it far >> more restrainedly). Guido> Which is why I didn't like the 'sum[x for x in S]' notation much. Guido> Let's look for an in-line generator notation instead. I like Guido> sum((yield x for x in S)) Guido> but perhaps we can make this work: Guido> sum(x for x in S) 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)? Assuming the result is a generator function (a first class object I can assign to a variable then call later), is there some reason the current function notation is inadequate? This seems to me to suffer the same expressive shortcomings as lambda. Lambda seems to be hanging on by the hair on its chinny chin chin. Why is this construct gaining traction? If you don't like lambda, I can't quite see why syntax this is all that appealing. OTOH, if lambda: x: x+1 is okay, then why not: yield: x for x in S ? Skip