Haskell powers pandoc, a couple of trading firms, and more and more systems at FB and Google. I don’t know if any of those things are practical but some are us

Haskell powers pandoc, a couple of trading firms, and more and more systems at FB and Google. I don’t know if any of those things are practical but some are useful and some make money ;) OCaml is also instructive. It’s a little more similar to “industry languages” but definitely close to Haskell; it also has reasonably broad adoption.