from a naive skim,it looks like a book that is about how to model category theory in SML.

A lot of the encodings seem to around that

I've over time gotten a lot out of efforts to model category theory in agda, one example being https://github.com/copumpkin/categories (though theres many more).

Along those lines, any idea where I might find some good, minimal examples of category theoretic models implemented in a mainstream language? I have no doubt that strictly typed functional languages have a more convenient syntax for these concepts, and that translating those into Python, or even Java, would be difficult. But not impossible, and it might even help to illustrate why Haskell and ML are appealing choices to someone wanting to use these models in production.

In case Common Lisp is mainstream: https://www.researchgate.net/publication/279847876_A_DSEL_fo...

I appreciate this. Thanks!

Here is a bit in Julia I wrote: https://github.com/jasonmorton/Cateno

(Python would be harder for this than Java.)

Definitely. I said that poorly, what I meant was "it'd unquestionably be hard in Python, and it'd even be hard in Java"

The pdf is from 2003, not clear whether much is dated later.

Curious, why does the date of the pdf matter? Not saying it applies here, but typically results in mathematics (unlike those in tech industry) do not become outdated and whatever is true today in mathematics is true tomorrow. So, for instance if you proven a mathematical theorem in 1661, then that theorem is still true today.

It doesn't except that it's standard to put the date in the link in HN if it's more than a year or so old.