When I run this, it works fine: p: 100#0; p[0]: 1; p[1]: 1; n: *&~p; p[n]: 2; p: p | 100#~!n

However, when I try to bundle the last three statements as a function with a single argument x and use [converge over](https://estradajke.github.io/k9-simples/k9/Adverb.html#cover) on it, it fails with `!class`. The code is: p: 100#0; p[0]: 1; p[1]: 1; {n: *&~x; x[n]: 2; x: x | 100#~!n}/:p

do you intend to implement that? as little as i can read your code, you are using a lenth n buffer as well: A y=gI(til(ai(xn)))
what is x(y(z)))?

2 more questions about mergesort:
- is it worth using a non-recursive algorithm (speed-wise)? the usual stack depth shouldn't be that deep
- using an initial pass to detect sorted-ranges, and maybe min-max spans. this would detect already sorted input, would require some additional complexity to handle ranges, and min-max spans could use histogram sorting for ints and symbols if there are <256 unique values