Do whatever's needed to get CPS (existing implementation <https://github.com/disruptek/cps> ) into the core+stdlib. If this requires a small breaking change, it's probably worth it;. CPS is incredibly useful for introspection, async, suspend to disk, migration between threads, migration between machines, millions of connections, logical-in-process-"fork", gluing with other languages, etc.
@disruptek built something that does a CPS transformation on (essentially any) Nim code, and then implements on top of that: try/catch, iterators, coroutines, "goto", and a bumch of other things with very short and simple implementations (tiny fractions of what it would take to implement them each on their own) and all at the user level (and without any backend-specific features). I recommend reading @disruptek 's doc, code and examples, and NOT look at Wikipedia/Matt Might's description/whatever google gives you. It's not that they are not wrong, but they are more often than not "can't see the forest for the trees". (and, in most cases, are complicated by the lack of facilities in the languages)
