[Python-Dev] Py2.6 ideas (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Fri Feb 16 13:38:04 CET 2007

Nick Coghlan schrieb:

However, another aspect that occurred to me is that inheriting from tuple has significant practical benefits in terms of speed and memory consumption, at which point it doesn't seem worthwhile to remove the indexing capability.

I'm not so sure that inheriting from tuple, and giving it named fields, has significant speed and memory benefits. In particular for the memory benefits, you can use slots to achieve the same effects, and more efficiently so (because it you don't store the tuple length). As for speed, I would have to see measurements to be convinced it is faster.

I suppose you could write a completely new C-level record class, but given that Raymond's NamedTuple class gets good performance from a Python implementation, rewriting it in C seems like wasted effort.

It wouldn't necessarily be rewriting: In the C API, you have already the PyStructSequence machinery (see posixmodule.c:stat_result_fields for an example). It's just that this machinery isn't available to Python code, yet, and no alternative convenience library is, either (other than using slots, which won't directly give indexed access).

Regards, Martin

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