[Python-Dev] PEP 409 and the stdlib (original) (raw)

Hrvoje Niksic hrvoje.niksic at avl.com
Tue May 21 15:23:44 CEST 2013

On 05/21/2013 02:57 PM, Serhiy Storchaka wrote:

21.05.13 13:05, Hrvoje Niksic написав(ла):

On 05/21/2013 11:56 AM, Serhiy Storchaka wrote:

try: x = d['key'] except KeyError: x = fallback('key')

def fallback(key): if key not in a: raise BusinessError(...) return 1 / a[key] # possible TypeError, ZeroDivisionError, etc Yes, in that case the exception will appear unintentional and you get the old message — it's on a best-effort basis. In both cases the BusinessError exception raised explicitly. How do you distinguish one case from another?

In my example code the "raise" keyword appears lexically inside the "except" clause. The compiler would automatically emit a different raise opcode in that case.

NB in your example the "raise" is just as intentional, but invoked from a different function, which causes the above criterion to result in a false negative. Even in so, the behavior would be no worse than now, you'd just get the old message.

Hrvoje

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