On 12/29/13 00:13, Burak Arslan wrote: > Hi, > > Have a look at the following code snippets: > https://gist.github.com/plq/8164035 > > Observations: > > output2: I can break out of outer context without closing the inner one > in Python 2 > output3: Breaking out of outer context closes the inner one, but the > closing order is wrong. > output3-yf: With yield from, the closing order is fine but yield returns > None before throwing.
It doesn't, my mistake. Python 3 yield from case does the right thing, I updated the gist. The other two cases still seem weird to me though. I also added a possible fix for python 2 behaviour in a separate script, though I'm not sure that the best way of implementing poor man's yield from. Sorry for the noise. Best, Burak > All of the above seem buggy in their own way. And actually, Python 2 > seems to leak memory when generators and context managers are used this way. > > Are these behaviours intentional? How much of it is > implementation-dependent? Are they documented somewhere? Neither PEP-342 > nor PEP-380 talk about context managers and PEP-343 talks about > generators but not coroutines. > > My humble opinion: > > 1) All three should behave in the exact same way. > 2) Throwing into a generator should not yield None before throwing. > > Best, > Burak > > ps: I have: > > $ python -V; python3 -V > Python 2.7.5 > Python 3.3.2 -- https://mail.python.org/mailman/listinfo/python-list
