Python, for example, will let you call async functions inside non-async functions, you just have to set up the event loop yourself. This isn't conceptually different than the Io thing here.
But the asyncio event loop is not reentrant, so your faux sync functions cannot be safely called from other async functions. It is an extremely leaky abstraction. This is not a theoretical possibility, I stumbled on the issue 15 minutes into my foray into asyncio (turns out that jupyter notebooks use asyncio internally).
There are ways around that (spawn a separate thread with a dedicated event loop, then block), or monkey patch asyncio, but they are all ugly.
except you cant "pass the same event loop in multiple locations". its also not an easy lift. the zig std will provide a few standard implementations which would be trivial to drop in.
I thought it was the exact same; an event loop in Python is just whatever Io is in Zig, make it a param, get it from an import and a lookup (`import asyncio; loop = asyncio.get_running_loop()`). I might be misunderstanding what you're saying though.
hm maybe. i guess ive only used python in situations where it injects it into amain so i could have been confused. i thought python async was a wrapper around generators, and so the mechanism cant be instantiated in multiple places. i stand corrected.
Per thread—once you start working in multiple threads you have the choice to have one global event loop, which comes at the cost of all async code being effectively serialized as far as threads are concerned*, or one event loop per thread.
* Which can be fine if your program is mostly not async but you have that one stubborn library. Yay async virality.
I can't say there's no good reason to have per thread event loops, but I think I can say if you do know of one you're suffering a terrible curse. I can only imagine the constraints that would force me to do this.
There are ways around that (spawn a separate thread with a dedicated event loop, then block), or monkey patch asyncio, but they are all ugly.