[Python-Dev] Arbitrary non-identifier string keys when using **kwargs (original) (raw)

Guido van Rossum guido at python.org
Tue Oct 9 13:26:50 EDT 2018

My feeling is that limiting it to strings is fine, but checking those strings for resembling identifiers is pointless and wasteful.

On Tue, Oct 9, 2018 at 9:40 AM Jeff Hardy <jdhardy at gmail.com> wrote:

On Sun, Oct 7, 2018 at 3:45 PM Terry Reedy <tjreedy at udel.edu> wrote: > > On 10/7/2018 1:34 PM, Chris Barker via Python-Dev wrote: > > On Fri, Oct 5, 2018 at 3:01 PM Brett Cannon <brett at python.org_ _> > <mailto:brett at python.org>> wrote: > > > > I'm also fine with saying that keys in **kwargs that are not proper > > identifiers is an implementation detail. > > > > > > It's not just **kwargs -- you can also use arbitrary names with > > setattr() / getattr() : > > > > In [6]: setattr(foo, "4 not an identifier", "this works") > > > > In [7]: getattr(foo, "4 not an identifier") > > Out[7]: 'this works' > > When this behavior of set/getattr was discussed a decade or so ago, > Guido said not to disable it, but I believe he said it should not be > considered a language feature. There are other situations where CPython > is 'looser' than the spec. > From an alternative implementation point of view, CPython's behaviour is the spec. Practicality beats purity and all that. > - Jeff _________________________ Python-Dev mailing list Python-Dev at python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/guido%40python.org

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