APL has a long an interesting history. It was successfully used for decades in Wall Street firms.

It's also worth looking at

* The A+ programming language, an APL derivative created at Morgan Stanley by Arthur Whitney. https://en.wikipedia.org/wiki/A%2B_(programming_language).

Roger Hui also worked there for a number of year.s

* The J language from Roger Hui - https://en.wikipedia.org/wiki/Roger_Hui#J_language

* Arthur Whitney and Kx Systems - https://en.wikipedia.org/wiki/Arthur_Whitney_(computer_scien...

Kona, a K implementation that's open source. https://github.com/kevinlawler/kona

Useful for reading K-tradition C programming style, too.

I've been puzzled about Kona for a while, since I don't really see a purpose for it. K/Q is specifically intended as a very high-efficiency language, and Kona doesn't say anything about benchmarks.

The original reason may have been that k3 was not open source and the free version was limited. But in general people write these things for all sorts of reasons. Just as there are dozens of Scheme interpreters.

And one chicago firm with APL in its name since its founding: https://www.manta.com/c/mm2mvtr/security-apl

Why would you admit that? If you don't know something, look it up. It's not someone else's fault if you don't know something. On HN and in the world, don't whine about it, do something about it.

But wasn't it fun to find out that it is A Programming Language?

There's this Google thing that can, however.

Not everything is meant for everybody having every background.

Why is this downvoted? I had the same problem and I am certain many others faced it too.

Substitute e.g. Python or C++ for APL. Do you still think the articly should explain that "C++ is a programming language."

It's probably because APL doesn't look anything like your typical PL.

Which — once you're acquainted with its existence — is the very thing that makes it instantly recognizable.

No. I would settle for a full form and even that should be mentioned only once in the start.