On Oct 27, 5:31 pm, Steven D'Aprano <steve +comp.lang.pyt...@pearwood.info> wrote: > From the outside, you can't tell how big a generator expression is. It has no > length:
I understand that. > Since the array object has no way of telling whether the generator will have > the correct size, it refuses to guess. It doesn't have to guess. It can assume that I, the programmer, know what the heck I am doing, and then validate that assumption -- trust, but verify. It merely needs to fill the slice and then ask for one more and check that StopIteration is raised. > I would argue that it should raise a TypeError > with a less misleading error message, rather > than a ValueError, so "bug". And I would argue that it should simply work, unless someone can present a more compelling reason why not. > The simple solution is to use a list comp > instead of a generator expression. I know how to work around the issue. I'm not sure I should have to. It violates the principle of least surprise for the ctypes array to not be able to interoperate with the iterator protocol in this fashion. Regards, Pat -- http://mail.python.org/mailman/listinfo/python-list
