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

Stefan Krah stefan at bytereef.org
Tue Aug 29 19:06:55 EDT 2017

On Tue, Aug 29, 2017 at 06:01:40PM -0400, Yury Selivanov wrote:

PEP 550 positions itself as a replacement for TLS, and clearly defines its semantics for regular functions in a single thread, regular functions in multithreaded code, generators, and asynchronous code (async/await). Everything is specified in the High-level Specification section. I wouldn't call slightly differently defined semantics for generators/coroutines/functions an "inconsistency" -- they just have a different EC semantics given how different they are from each other.

What I don't find so consistent is that the async universe is guarded with async {def, for, with, ...}, but in this proposal regular context managers and context setters implicitly adapt their behavior.

So, pedantically, having a language extension like

async set(var, value) x = async get(var)

and making async-safe context managers explicit

async with decimal.localcontext(): ...

would feel more consistent. I know generators are a problem, but even allowing something like "async set" in generators would be a step up.

Stefan Krah

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