> By contrast, calling async code from sync code requires a special blocking wrapper (Python) ...
That's exaclty my point. If you don't have async by default in your platform you need to do stupid things to fake it. If function calls and main in Python were innately async you could be calling async code just as easily as sync code.
> [...] or unavoidably breaks control flow (JavaScript).
async/await syntax avoids it completely.
Tbh await should be default function call semantics and there should be special keyword for calling without awaiting. But since we come from sync primitives that would require small revolution that might happen at some point.
> Async is syntactic sugar
You could make sync code be syntactic sugar for await.
> would require small revolution that might happen at some point.
or python could have blessed gevent and done away with all the nonsense.
I hope that someone does an oral history of why gevent wasn't seen as the solution here. The existence of models like Twisted, and a general idea that yields to an event thread should be explicit in some way, I think caused the exact kind of fracturing of the ecosystem that everyone was trying to avoid. "Everyone will write async code" simply didn't happen in practice.