[Python-Dev] Tightening up the specification for locals() (original) (raw)

Maciej Fijalkowski fijall at gmail.com
Mon May 13 13:40:27 CEST 2013

On Sun, May 12, 2013 at 2:01 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:

On Fri, 03 May 2013 12:43:41 +1000 Steven D'Aprano <steve at pearwood.info> wrote:

On 03/05/13 11:29, Nick Coghlan wrote: > An exchange in one of the enum threads prompted me to write down > something I've occasionally thought about regarding locals(): it is > currently severely underspecified, and I'd like to make the current > CPython behaviour part of the language/library specification. (We > recently found a bug in the interaction between the prepare method > and lexical closures that was indirectly related to this > underspecification)

Fixing the underspecification is good. Enshrining a limitation as the one correct way, not so good. I have to say, I agree with Steven here. Mutating locals() is currently an implementation detail, and it should IMHO stay that way. Only reading a non-mutated locals() should be well-defined. Regards Antoine.

Like it or not, people rely on this behavior. I don't think CPython (or PyPy) can actually afford to change it. If so, documenting it sounds like a better idea than leaving it undocumented only known to the "inner shrine"

Cheers, fijal

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