FAQ

Why yield — why not await like is normally seen for coroutines?

The reason is that await does not offer a suspension point to an event loop (it just calls __await__ and maybe that offers a suspension point), so if we wanted to use that syntax then we'd need to replace yield coro with something like await tinyio.Task(coro). The traditional syntax is not worth the extra class.

I have a function I want to be a coroutine, but it has zero yield statements, so it is just a normal function?

You can distinguish it from a normal Python function by putting if False: yield somewhere inside its body. Another common trick is to put a yield statement after the final return statement. Bit ugly but oh well.

vs asyncio or trio?

I wasted a lot of time trying to get correct error propagation with asyncio, trying to reason whether my tasks would be cleaned up correctly or not (edge-triggered vs level-triggered etc etc). trio is excellent but still has a one-loop-per-thread rule, and doesn't propagate cancellations to/from threads. These points inspired me to try writing my own.

tinyio has the following unique features, and as such may be the right choice if any of the following are must-haves for you:

• the propagation of errors to/from threads;
• no one-loop-per-thread rule;
• simple+robust error semantics (crash the whole loop if anything goes wrong);
• tiny, hackable, codebase.

Conversely, at least right now we don't ship batteries-included with a few things:

• asynchronously launching subprocesses / making network requests / accessing the file system (in all cases use run_in_thread instead);
• scheduling work on the event loop whilst cleaning up from errors.

If none of the bullet points are must-haves for you, or if any of its limitations are dealbreakers, then either trio or asyncio are likely to be better choices. :)