Your kata seems really interesting. I will give it a go after I'm done with this one.

It was a fun one with a clear discription and illustration. Not sure if input validation is appropriate for this kata level or not, but nice work regardless.

I assume that if multiple rotors were to be chained, the second part of the output of rotor(n) would be the second argument for rotor(n+1)'s process.

As I understand, an invalid letter should be "ignored" as if it wasn't input. That's why I think the output False makes sense and this shouldn't be an issue.

The description however should clarify that, something like :should not affect the internal state of the machine AND output the character unchanged with False as the socond part

Amazing concept for a kata, enjoyed solving it very much. There are some improvements to be made however.

The mechanism is complicated and difficult to explain, but something like @MMMAAANNN's comment could replace the tables in the description as it was much clearer.

Just like @Voile mentionned, the rotate argument isn't explained. I thought it would be introduced in a later part of the series until I saw the "Check notching during non-rotation" test cases.

Also, there are no test cases to validate the inputs other than the wiring.

The kata was very enjoyable, but it's a shame that it seems to have been abandonned.

Thank you for the illustration. It made things much clearer.

Thank you for this kata. Took some time (and a lot of code) but I highly enjoyed comeing up with a solution just how I wanted it.

Loved your solution and how structured it is. Learned a lot from it as well.

In Jmp::from_sv, why do you add the other Traits to Call, why not Call by itself?