I am playing with and learning April[1], a subset of APL that compiles to Lisp. It is a blast for me, because I had programmed a bit in Lisp in the 90s, and then I found J around 2011/12. I always loved Lisp, and I didn't really get into Clojure, although it is a nice language. I had heard of APL when I had my Commodore PET 2001 in 1977 and my Vic20 later, but I never got to play with it. Once I did back in 2015, and the APL characters resonated with me (hard to find keyboard input workarounds etc.) because I was free of the associations of ASCII and the symbols made sense as I learned it a bit in their graphic representation and function. I have dreamed of having a real, modern Lisp Machine, so maybe I can get some of that with Mezzano. I am not sure how hard or easy it would be for April's creator, Andrew Sengul (##phantomics) to swing that, but I would participate in a crowdsourcing of it (on The Framework notebook[2] would be the icing on the cake!). I don't know enough of Mezzano to say how vialbe it really is, but I am hoping! I didn't quite get April right away, but I am really starting to appreciate it (with Andrew's help, and the APL community). Andrew's 'Why April' section, poetic and seemingly hyperbolic, is ringing less hyperbolic and more true as I get to know this twisted marriage of PLs: Lisp's legacy, tons of libs, emacs/slime, debugging, and parentheses, yes those beautiful things, to handle all the "front end" programming you could ever need, to feed the array-munching and alchemy of APL. And what about Python? I refer all Pythonistas to take heed of their and MIT's sinful choice to worship the serpent and casting us out from the garden of Lisp! Just read Milton's Paradise Lost, Book X, around verse 550-ish ;)

Machine learning which is heavily based on arrays or array math in their implementation, hence the popularity of libs to handle them like Pandas and NumPy (inspired by J, by the way. Ask Wes McKinney), has some nice nuggets or implementations of an ELM (Extreme Learning Machine) in J called 'JELM'[3], CNNs in APL[4] with some benchmarks, or getting APL into optimized GPU code via Futhark[5] and apltail[6]. And under some of those covers is Haskell as a treat!

Ah, yes we live in interesting times!

A link to an HN post in 2020 by Andrew:

[0] https://news.ycombinator.com/item?id=24434717

[1] https://github.com/phantomics/april

[2] https://frame.work/

[3] https://github.com/peportier/jelm

[4] https://dl.acm.org/doi/10.1145/3315454.3329960

[5] https://futhark-lang.org/blog/2016-06-20-futhark-as-an-apl-c...

[6] https://github.com/melsman/apltail/

Milton reference for the pious (with no parentheses;) or proper line breaks, sorry!)

Now Dragon grown, larger then whom the Sun
Ingenderd in the Pythian Vale on slime,
Huge Python, and his Power no less he seem’d
Above the rest still to retain; they all
Him follow’d issuing forth to th’ open Field,
Where all yet left of that revolted Rout
Heav’n-fall’n, in station stood or just array,
Sublime with expectation when to see
In Triumph issuing forth thir glorious Chief;
They saw, but other sight instead, a crowd
Of ugly Serpents; horror on them fell,
And horrid sympathie; for what they saw,
They felt themselvs now changing; down thir arms,
Down fell both Spear and Shield, down they as fast,
And the dire hiss renew’d, and the dire form
Catcht by Contagion, like in punishment,
As in thir crime.