[Python-Dev] PEP 550 v3 (original) (raw)

Yury Selivanov yselivanov.ml at gmail.com
Mon Aug 21 20:41:45 EDT 2017

On Mon, Aug 21, 2017 at 8:06 PM, Guido van Rossum <guido at python.org> wrote: [..]

> OK, this really needs to be made very clear early in the PEP. Maybe this > final sentence provides the key requirement: changes outside the > generator > should make it into the generator when next() is invoked, unless the > generator itself has made an override; but changes inside the generator > should not leak out through next().

It's covered here with two examples: https://www.python.org/dev/peps/pep-0550/#ec-semantics-for-generators I think what's missing is the fact that this is one of the key motivating reasons for the design (starting with v2 of the PEP). When I encountered that section I just skimmed it, assuming it was mostly just showing how to apply the given semantics to generators. I also note some issues with the use of tense here -- it's a bit confusing to follow which parts of the text refer to defects of the current (pre-PEP) situation and which parts refer to how the proposal would solve these defects.

I see. The proposal always uses present tense to describe things it adds, and I now see that this is indeed very confusing. This needs to be fixed.

Yury

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