Oct. 21, 2003
8:55 p.m.
[Guido]
... BTW, while Alex has shown that a generator function with no free variables runs quite fast, a generator expression that uses variables from the surrounding scope will have to use the nested scopes machinery to access those, unlike a list comprehension; not only does this run slower, but it also slows down all other uses of that variable in the surrounding scope (because it becomes a "cell" throughout the scope).
The implementation could synthesize a generator function abusing default arguments to give the generator's frame locals with the same names.