[Python-Dev] genexps slow?
tim.one at comcast.net
Mon Apr 5 14:45:51 EDT 2004
>> There's a twist there: the functions synthesized for generator
>> expressions get to take the quicker-than-general "fast_yield" exit
>> path. Hmm! It looks like tests against WHY_YIELD before the
>> fast_yield label can no longer succeed, but are still there to slow
>> down non-generator cases.
> Hmm. I *think* I agree with you. I also think the tests against
> WHY_YIELD in the code for END_FINALLY are unnecessary,
I meant that one too: all tests against WHY_YIELD physically preceding the
fast_yield label appear unnecessary now. The only obvious assignment of
WHY_YIELD to "why" appears in YIELD_VALUE now, and that jumps immediately to
fast_yield, from which there's no going backwards. do_raise() can't return
> as we (syntactically) don't allow yields when there are finally:
> statements in play.
Even if we did, a yield doesn't collapse any pending block structure.
> If I'm wrong about that, then you're wrong too :-) It's all
> a bit subtle, to be sure.
Na <wink>. I'll toss in some asserts and check it in if nothing blows up.
> Once again, I wonder if there was someway we could have two
> eval_frames: one with tracing support, one without. Unfortunately, I
> don't think this can fly (how do you *start* tracing?). Maybe we
> could have a '-notrace' command line flag? But I suspect that this is
> a silly over-complication.
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