On Thu, 12 May 2005, Guido van Rossum wrote:
> Define "raise". Does that involve a raise statement?
Not necessarily; it could be a raise statement or an inadvertently
triggered exception, such as in the example code i posted.
> What about 1/0?
That counts.
> What if you call a method that executes 1/0?
That counts too.
> What if that method catches that exception?
Did you mean something like this?
def handle():
try:
open('spamspamspam')
except:
catchit()
# point A
...
def catchit():
try:
1/0
except:
pass
Then there's no exception to propagate, so it doesn't matter.
Once we're get to point A, the division by zero is long forgotten.
> What about the StopIteration conceptually
> raised by next() called by the for-loop implementation?
It's "caught" by the for-loop, so to speak, so it never gets out.
Conceptually, the for-loop expands to:
while 1:
try:
item = it.next()
except StopIteration:
break
# body of loop goes here
The 'break' can't possibly cause an exception, so the StopIteration
exception isn't retained.
> I believe there are (at least) two use cases:
>
> (1) I catch some low-level exception (e.g. socket.error) and turn it
> into a high-level exception (e.g. an HTTPRequestFailed exception).
>
> (2) I write some exception handling code and somehow a bug in the
> handler (or an uncooperative environment, e.g. a full disk) causes the
> exception handling code to trip over an exception.
>
> I'm fairly certain (but not 100%) that Ping meant to include both use cases.
Yes, though i did not expect to provide any mechanism for distinguishing
the two cases. Do you think such a mechanism would be necessary?
-- ?!ng
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
