[Python-Dev] PEP 550 v4 (original) (raw)

Yury Selivanov yselivanov.ml at gmail.com
Wed Aug 30 09:44:59 EDT 2017

On Wed, Aug 30, 2017 at 8:19 AM, Koos Zevenhoven <k7hoven at gmail.com> wrote:

On Wed, Aug 30, 2017 at 2:36 AM, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:

Yury Selivanov wrote:

While we want "yield from" to have semantics close to a function call, That's not what I said! I said that "yield from foo()" should have semantics close to a function call. If you separate the "yield from" from the "foo()", then of course you can get different behaviours. But that's beside the point, because I'm not suggesting that generators should behave differently depending on when or if you use "yield from" on them. For (1) we want the context change to be isolated. For (2) you say that the context change should propagate to the caller. No, I'm saying that the context change should always propagate to the caller, unless you do something explicit within the generator to prevent it. I have some ideas on what that something might be, which I'll post later. FYI, I've been sketching an alternative solution that addresses these kinds of things. I've been hesitant to post about it, partly because of the PEP550-based workarounds that Nick, Nathaniel, Yury etc. have been describing, and partly because that might be a major distraction from other useful discussions, especially because I wasn't completely sure yet about whether my approach has some fatal flaw compared to PEP 550 ;).

We'll never know until you post it. Go ahead.

Yury

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