Have you ever had one of those notepads with the kind of paper that made you want to write something, anything, even though you had nothing to write about? OCaml is just like that to me.

I stroll through the internet aimlessly and I find a page that mentions OCaml and my eyes light up; I see an .ml file and savor how it looks - functions written with great economy of expression, pattern matching through which data flows in well-defined pathways, abstract data types forming a network of rugged pipes and girders that makes invalid states impossible; and .mli files that presents modules like classic prose -- no hedges, contortions, or obscurities that undercut the reader's ability to understand the flow of data and the pathways through which it flows.

"Expression, carrying the elegance that comes from compressed energy, is like a perfectly tuned stringed instrument: the strings are taut to exact degrees to correspond to exact pitches that stand in exact relations to one another. The pitches and their relations exist before the strings are tuned. Each string is tuned to a pitch and the results are judged by comparison to this pre-existing reality. A musician tuning an instrument is not finished until everything is exactly right, but once it is exactly right, there is simply nothing left to do." -- Clear and Simple as the Truth: Writing Classic Prose, Thomas, Turner.

Thanks for this (and the child comments). I was just about to post a “which functional language should I pick up” ask HN but I got most of my answer from this thread :D

I learned to program in Caml (20 years ago now... it still seems like yesterday) but switched to curly brackets land when I started working, and more recently Python. Last month I started reading Learn You a Haskell for Great Good and that made me nostalgic for FP. Haskell’s syntax and strict management of side effects is a bit of a turn-off though. The article and the comments have firmly put me in the Caml camp, but now I have to figure out which version (OCaml, F#, ReasonML) to go for.

Advice or opinions on the topic are welcome!

If you want to write a command-line application, you can choose either OCaml or Reason, depending on your taste of syntax - both compile to native statically linked binaries. If you're doing anything related to compilers, OCaml is particularly suited for that, and you'll be in very good hands with Menhir (see: https://pl-rants.net/posts/case-for-new-lang/). Another systems software written in OCaml is unison (https://github.com/bcpierce00/unison), which is a file synchronization tool with a clear specification.

But if you want to write database backed web application servers in OCaml, with sessions, background jobs, admin interfaces, ORMs, database migrations and all that jazz, then you might want to give F# a go, or Haskell which has a better story around it. I do have a tiny Node server written in Reason that I use as an API endpoint but if I were to build a full-fledged system, there is nothing yet in the OCaml world like Rails or Django.