So, what this is: it's a Nim macro that rewrites your regular procedural code into a continuation using the CPS transform; this offers you total power over the flow control of your code and allows you to build things like coroutines, async I/O schedulers, iterators, exceptions, all as first class citizens in the language. It has been under development for quite some time and is pretty much mature.
Relevant recent articles:
- https://without.boats/blog/let-futures-be-futures/
- https://adam.nels.onl//blog/maybe-everything-is-a-coroutine/