This got me thinking of Hy. I wonder how syntactically close they are; there might be an exploitable Python -> Hy -> Janet path here.

[0] https://hylang.org/

I used Hy for a long time, then tried Janet, and ultimately realized that I wanted more batteries included but didn't want Python... So I forked https://github.com/rcarmo/go-joker and am tinkering with it until it does all I want.