[lmm]

> Try catch is not a heavy lift of a seam between red and blue

> To be fair, #3 seems to have shades of grey. In some pls, you can call an async function from a sync one by wrapping it in a whole damn event loop system. Should that count?

I think you have to count any extra overhead where you can't just write f(), including try/catch. It's always possible to call whatever kind of function from whatever other kind of function if you put enough effort and hackery in, so if we can't use functions of kind x in functions of kind y as normal "f()" function calls then that has to be what we mean by colouring.