Comment by 1vuio0pswjnm7

Other than ngn/k ...

https://ktye.github.io/kdoc.htm

https://github.com/ktye/i/releases/download/latest/k.c

IIRC, some old UNIX versions had an APL interpeter in the userland. For me, a k interpreter could be the ultimate UNIX utility. But interoperability with pipes and other UNIX utilities is awkward to say the least, as is having to use other programming languages as duct tape.