[Python-Dev] PEP 455: TransformDict (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Tue Oct 8 17:05:17 CEST 2013

Le Tue, 8 Oct 2013 22:49:28 +1000, Nick Coghlan <ncoghlan at gmail.com> a écrit :

> Well, you could ask the same question about OrderedDict, > defaultdict or Weak*Dictionary since neither of them use > composition :-)

We did ask the same question about those (except the Weak* variants, simply due to age). Each time, the point that each new dict variant would be used to justify yet more variants was a cause for concern.

Could you explain? I don't understand.

"Composition doesn't work with some mappings" isn't an adequate answer to the criticism that a composition based design could work with more mappings than just the builtin dict.

Fair enough.

Regards

Antoine.

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