hi everyone! i’ve written an SKI interpreter in kakoune (without shell), partially for practice with reduction strategies and inference rules for class, and mostly for a challenge 
it isn’t quite a proof that kakoune is turing complete because it takes a finite number of reduction steps. perhaps this is a good thing, so that trying to reduce SII(SII) doesn’t hang, but i would love to hear of an unbounded loop or recursion method if anyone has found one! (kakoune could also be patched to remove its nest depth and recursion limits, but that feels like cheating.)