[Python-Dev] PEP 3103: A Switch/Case Statement (original) (raw)

Armin Rigo arigo at tunes.org
Fri Jun 30 10:19:21 CEST 2006

Hi,

On Mon, Jun 26, 2006 at 12:23:00PM -0700, Guido van Rossum wrote:

Feedback (also about misrepresentation of alternatives I don't favor) is most welcome, either to me directly or as a followup to this post.

So my 2 cents, particularly about when things are computed and ways to control that explicitly: there was a point in time where I could say that I liked Python because language design was not constrained by performance issues. Looks like it's getting a matter of the past, small step by small step. I'll have to get used to mentally filter out 'static' or whatever the keyword will be, liberally sprinkled in programs I read to make them slightly faster.

Maybe I should, more constructively, propose to start a thread on the subject of: what would be required to achieve similar effects as the intended one at the implementation level, without strange early-computation semantics?

I'm not talking about Psyco stuff here; there are way to do this with reasonably-simple refactorings of global variable accesses. I have experimented a couple of years ago with making them more direct (just like a lot of people did, about the "faster LOAD_GLOBAL" trend). I dropped this as it didn't make things much faster, but it had a nice side-effect: allowing call-backs for binding changes. This would be a good base on top of which to make transparent, recomputed-when-changed constant-folding of simple expressions. Building dicts for switch and keeping them up-to-date... Does it make sense for me to continue this discussion?

A bientot,

Armin.

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