I'm looking for a particular introductory APL paper I read when I first got into APL. All of a sudden I can't find it, but it's definitely easy to find! It's about 5 pages, and has cute drawings. I thought it was Notation as a Tool of Thought, but clearly it's another one.
Rob Pike, of Golang, made an APL in Go. It's called Ivy. As an aside, it might be interesting to compare the speed of Ivy to Dyalog.
Ivy is a bignum calculator, and it's definitely instantaneous for things like */iota 10000, the factorial of 10,000. It's of the order of 10^35,659, where even factorial of 1,000 is a Domain Error in Dyalog, and I assume most other langs.