The docs say it's largely complete.

As an example of a headache, one node type in Judy has a count, followed by that many index bytes, followed by the same number of pointers. In Rust, that would naturally be a struct with two variable-sized fields, which isn't possible, so it's done by defining a struct generic over a pair of array types:

https://github.com/adevore/rudy/blob/300f2cc7842f6329a76fff0...

It looks to me like this is only ever instantiated for 2, 7, or 31 elements, whereas i think for original Judy, it can be any size up to 31 elements (maybe?). Handling a genuinely variable length in Rust would be rather gnarly, because there have to be different types for each length.