moonphase

Fun! From the repo[0]: > Your function must be self-contained, such that someone could copy-paste it into their code and not get an error. It also must not effect the environment outside it if at all possible (no #define or mutating globals). It must be as "pure" and self-contained as the language will allow. This is an interesting restriction, actually, with respect to style. The “natural” way I would program such an algorithm certainly doesn’t adhere to this requirement. Producing functions that are still correct, idiomatic and legible while producing minimal changes to environment or state requires a non-beginners understanding of the runtime nature of the language. [0]: https://github.com/oliverkwebb/moonphase?tab=readme-ov-file#...