I think the closest I've gotten to writing anything serious in a functional language has been writing a packaging system in nix— and that's definitely been a mi

I think the closest I've gotten to writing anything serious in a functional language has been writing a packaging system in nix— and that's definitely been a mind-expanding exercise, in particular appreciate how immutability interplays with overlays and what it means to find the fixed point and then unroll all that lazy stuff into a sequence of concrete evaluations. Now, that said, those insights haven't been something that I've then turned around and felt like I missed when using a normal imperative language like Python or Rust. But they are pretty nifty, no doubt about it.