AFAIU, the French Tax Code is effectively defined in terms of an algorithm. There was a recent HN thread (https://news.ycombinator.com/item?id=25208853) on a new open-source compiler for the tax code (https://arxiv.org/abs/2011.07966). The paper for the compiler references some interesting literature on the computability of legal codes. For example,

> [U.S.] tax law drafting style follows default logic, a non-monotonic logic that is hard to encode in languages with first-order logic (FOL).