[Python-Dev] namedtuple implementation grumble (original) (raw)

Steven D'Aprano steve at pearwood.info
Mon Jun 9 01:31:17 CEST 2014

On Sun, Jun 08, 2014 at 03:13:55PM -0400, Eric V. Smith wrote:

On 6/7/2014 10:46 AM, Nick Coghlan wrote: > On 7 June 2014 04:50, Chris Withers <chris at simplistix.co.uk> wrote: >> Curious as to what lead to that implementation approach? What does it buy >> that couldn't have been obtained by a mixin providing the functionality? > > In principle, you could get the equivalent of collections.namedtuple > through dynamically constructed classes. In practice, that's actually > easier said than done, so the fact the current implementation works > fine for almost all purposes acts as a powerful disincentive to > rewriting it. The current implementation is also really easy to > understand, while writing out the dynamic type creation explicitly > would likely require much deeper knowledge of the type machinery to > follow.

As proof that it's harder to understand, here's an example of that dynamically creating functions and types: [...]

I wonder how a hybrid approach would work? Use a dynamically-created class, but then construct the new method using exec and inject it into the new class. As far as I can see, it's only new that benefits from the exec approach.

Anyone tried this yet? Is it worth an experiment?

-- Steven

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