Adam Olsen <rhamph <at> gmail.com> writes: > > By the way, another interesting sys.exc_info() case: > > > > def except_yield(): > > try: > > raise TypeError > > except: > > yield 1 > > > > def f(): > > for i in except_yield(): > > return sys.exc_info() > > > > Right now, running f() returns (None, None, None). But with rewritten exception > > stacking, it may return the 3-tuple for the TypeError raised in except_yield(). > > What exception stacking? I thought we'd be using a simple per-thread > exception. I'd expect the yield statement to clear it, giving us > (None, None, None).
There is a per-thread exception for the current exception state but we must also save and restore the previous state when we enter and leave an exception handler, respectively, so that re-raising and sys.exc_info() work properly in situations with lexically nested exception handlers. Also, "yield" cannot blindingly clear the exception state, because the frame calling the generator may except the exception state to be non-None. Consequently, we might have to keep the f_exc_* members solely for the generator case. _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
