Comment by pnako
7 years ago
I said: it's not _that_ useful. I did not say it's completely useless.
Every large (or even small) company has people writing stuff in Perl, Bash, Haskell, Ruby, Rust, VBA, Scala, Lua or what not. I've been that guy, too.
More often than not it is a distraction more than anything, and it ultimately ends up being rewritten in C++, Java or Python. I think there are some niches where it helps; OCaml has had some success with static analysis and proof assistants, or even with code generation projects like FFTW.
Honestly, do you really think a company with only 35 engineers could build, scale and sell a product like WhatsUp for even a fraction of that amount but using C++, Java or Python? I seriously doubt that.
Look, I've seen both sides and I know this for sure (this isn't a mere opinion, this is a certain fact) - FP allows to build and maintain products using smaller teams.
You don't have to trust my word, do your research, google "companies using Clojure" (or Haskell, OCaml, Erlang, etc). You will see that either those companies are not too big, or the FP teams in large companies not very large. Skeptics often cite this fact, claiming it to be the proof that FP codebases don't scale to large teams. The truth is - you don't need a big team to build a successful product with FP language. And the number of startups using FP langs is steadily growing.