I had the experts write markdown files that contained the rules looked somewhat like:

## 1A Rule name

Some prose explaining the rules liking to official documentation.

``` if municipality and inhabitants > 10000 then functionA else functionB ```

Then a trivial parser would extract the rules, the DSL was then handled by Lark[1]. So pretty simple, but it made collaborating with experts easier as simulated results would also output some markdown they could read.

1. https://lark-parser.readthedocs.io/en/stable/

Sounds like "Literate Programming", where the code and comments are reversed: instead of everything being code except what's marked as a comment, everything is a comment except what's marked as code.

I am also very interested!