Hi Lassi,

I ended up putting things into one file with lots (not really) of
cond-expand-s (it's not exactly what you suggest, but it's a way too):
https://github.com/scheme-requests-for-implementation/srfi-253/pull/16/files

But thanks for the suggestions anyway—lots of things to think on and refactor!

Best of luck,
--
Artyom Bologov
https://aartaka.me