[Python-Dev] why not "return StopIteration"?
Barry A. Warsaw
Fri, 22 Jun 2001 12:30:44 -0400
>>>>> "GvR" == Guido van Rossum <firstname.lastname@example.org> writes:
| - Calling an end() function would require two calls per
| iteration. Two calls is much more expensive than one call
| plus a test for an exception. Especially the time-critical
| for loop can test very cheaply for an exception.
Plus, if the exception is both raised and caught in C, it is never
instantiated, so exception matching is a pointer compare. I know this
isn't the case with user defined iterators (since Python's raise
semantics is to instantiate the exception), but it helps.