Fair. I didn't know if there was any practice overlap.

For me, lisp is bigger in the meta programming. Really pulls the covers back on how things relate. Not just in how to put the code together, but how to look at the data.

Scala was my first big intro to category theory. Helped me see relations in some higher ideas. Many, though, are hard to see a priori.

The issue i have with metaprogramming (lisp or elixir but also C++ macro) is that it is easy to forget, unlike most programming principle. It require you to twist your mind, and if you stop for two-three years, it require efforts to put your head back in that space.

I've found that as long as you keep it transparent and focus on what the shape of the data is, things go easier than you'd expect.

That said, a lot of things folks reach for with meta programming, I think should get a pass. The goal shouldn't be to make the code like a text. The goal should be to heavily leverage core data structures.