On Mon, 23 Jul 2018 11:12:45 -0400 David Mertz <me...@gnosis.cx> wrote: > > The particular names I use are nothing special, and better ones might be > found. I just called the class NoneAware and the "escape" method > `.unbox()` because that seemed intuitive at first brush. > > I don't disagree that needing to call .unbox() at the end of the chained > attribute access is a little bit ugly. But it's a lot less ugly than large > family of new operators. And honestly, it's a nice way of being explicit > about the fact that we're entering then leaving a special world where > attribute accesses don't fail. > > I haven't implemented the equivalent dictionary lookups in the below. That > would be straightforward, and I'm sure my 5 minute throwaway code could be > improved in other ways also. But something better than this in the > standard library would address ALL the actual needs described in PEP 505. > Even the pattern Steve Dower is especially fond of like: > > favorite = cfg?.user?.profile?.food ?? "Spam" > > > (i.e. a configuration may be incomplete at any level, if levels are missing > default favorite food is Spam). We could simply spell that: > > favorite = NoneAware(cfg, "Spam").user.profile.food.unbox() > > > I think that's 14 characters more in this example, but still compact. We > could get that down to 2 characters if we used one-letter names for the > class and method. I suppose down to zero characters if .unbox() was a > property.
You could use .__call__() instead of .unbox(). Also you can make unboxing unnecessary in most cases by having your class proxy most operations, like weakref.proxy does. The "wrapt" library may help with that: http://wrapt.readthedocs.io/en/latest/wrappers.html Regards Antoine. _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
