Since effects are powerful enough to implement generators and cooperative multitasking, it seems like it’s more than just exceptions? Calling some functions could task-switch and do arbitrary computation before returning at some arbitrary time later. It might be nice to know which function calls could do that.

I’m not a fan of how ‘await’ works in JavaScript because accidentally leaving it out causes subtle bugs. But the basic idea that some function calls are simple and return immediately and others are not makes sense.