These mini-languages almost always become really painful to work with. If I find myself needing to implement some sort of configurable shared thing more complex

These mini-languages almost always become really painful to work with. If I find myself needing to implement some sort of configurable shared thing more complex than a table of regular expressions I just jump straight to the endgame and embed lua or a lisp. I think the target audience of JsonLogic is sharing code on the frontend/backend. I think these days javascript is common for that. A tiny lisp would be suitable as well. There's a special place in hell reserved for people who make me edit ad-hoc turing complete configuration languages embedded in json or xml.