On Fri Mar 7 20:54:31 CET 2014, Chris Angelico wrote: > On Sat, Mar 8, 2014 at 5:58 AM, Jim J. Jewett <jimjjewett at gmail.com> wrote: >> (Thu Mar 6 23:26:47 CET 2014) Chris Angelico responded: >>> ...[as-capturing is] deferred until there's a non-closure means of >>> creating a sub-scope. >> The problem is that once it is deployed as leaking into the parent >> scope, backwards compatibility may force it to always leak into >> the parent scope. (You could document the leakage as a bug or as >> implementation-defined, but ... those choices are also sub-optimal.) > It'll never be deployed as leaking, for the same reason that the > current 'except' statement doesn't leak: I don't think that is the full extent of the problem. From Nick's description, this is a nasty enough corner case that there may be glitches no one notices in time. The PEP should therefore explicitly state that implementation details may force the deferral to be permanent, and that this is considered an acceptable trade-off. -jJ -- Sorry for the botched subject line on the last previous message. If there are still threading problems with my replies, please email me with details, so that I can try to resolve them. -jJ _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
- Re: [Python-Dev] PEP 463: Exception-catching expressions Thomas Wouters
- Re: [Python-Dev] PEP 463: Exception-catching expressions Chris Angelico
- [Python-Dev] Alternative forms [was: PEP 463: Exception-ca... Jim J. Jewett
- Re: [Python-Dev] Alternative forms [was: PEP 463: Exceptio... Chris Angelico
- Re: [Python-Dev] Alternative forms [was: PEP 463: Exceptio... Jim J. Jewett
- Re: [Python-Dev] Alternative forms [was: PEP 463: Exceptio... Chris Angelico
- [Python-Dev] Why not make frames? [was: Alternative forms ... Jim J. Jewett
- Re: [Python-Dev] Why not make frames? [was: Alternative fo... Chris Angelico
- Re: [Python-Dev] Why not make frames? [was: Alternative fo... R. David Murray
- Re: [Python-Dev] Why not make frames? [was: Alternative fo... Ethan Furman
- [Python-Dev] Scope issues [was: Alternative forms [was: PE... Jim J. Jewett
- Re: [Python-Dev] Scope issues [was: Alternative forms [was... Chris Angelico
- Re: [Python-Dev] PEP 463: Exception-catching expressions Steven D'Aprano
- Re: [Python-Dev] PEP 463: Exception-catching expressions Terry Reedy
- Re: [Python-Dev] PEP 463: Exception-catching expressions Greg Ewing
- Re: [Python-Dev] PEP 463: Exception-catching expressions Nick Coghlan
- Re: [Python-Dev] PEP 463: Exception-catching expressions Chris Angelico
- Re: [Python-Dev] PEP 463: Exception-catching expressions Glenn Linderman
- Re: [Python-Dev] PEP 463: Exception-catching expressions Chris Angelico
- Re: [Python-Dev] PEP 463: Exception-catching expressions Glenn Linderman
- Re: [Python-Dev] PEP 463: Exception-catching expressions Chris Angelico