Ada code is not very beautiful nor mathematically elegant. I think _despise_ is probably too strong but all the things people like about Haskell and Lisp are not in Ada.

I think the author probably thinks Ada's type system is more powerful than it actually is (or is just thinking of SPARK). Ada is basically just verbose C with a slightly nicer type system and better aliasing rules.

I think that in imperative programming, like in Ada, the mathematical elegance comes from ensuring the post-conditions from pre-conditions and maintaining invariants and so on.

I'm seeing a new generation of kids coming out of school who are just pissing on those techniques: only functional is mathematical, and the rest is outdated, intractable garbage that causes software crises and meltdowns.

That's reasonable (and I actually do like Ada somewhat) but the satisfaction of figuring out a nice algorithm in APL and writing an equivalent in Ada are just… not the same.

Though I'm not really sure I'd call maintaining invariants and pre/postconditions mathematical elegance per se, it feels like good engineering. Like you've built something that's solid.

I love Lisp, and I don't despise Ada. I mean, I would never pick it over Lisp for a new project (well, I can think of one or two very narrow niches where it would probably be the most appropriate choice), but I would rate Ada above, say, Java, C++, and Go.