Le Tue, 8 Oct 2013 22:12:02 +1000, Nick Coghlan <ncogh...@gmail.com> a écrit : > > It's OK if the key transforming API has to constrain the behaviour of > the underlying mapping or require an appropriately designed transform > function to handle more esoteric containers. Either would still be > better than categorically *disallowing* composition to the point > where you can't even compose it with OrderedDict.
Well, you could ask the same question about OrderedDict, defaultdict or Weak*Dictionary since neither of them use composition :-) > ChainMap doesn't > compose sensibly with arbitrary mappings like defaultdict, but > composition is still the right design choice because it works well > with *most* custom mappings. ChainMap is easy to compose since it doesn't have to keep any data-driven internal state. > It's not that I think this is necessarily a *bad* idea (although the > composability problem gives me grave doubts), it's that I think it's > not an *urgent* idea, so why rush to review and include it in the > weeks remaining before the beta, when the option of publishing it as > a recipe or a PyPI module remains available? It's just that I disagree we're rushing anything. The feature is fairly simple, many people have already had a need for something like that. (and amongst those people absolutely *zero* have said the design of the feature proposal is inadequate) Regards Antoine. _______________________________________________ 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
