It turns out that Ocaml is a fairly simple language to learn. Very few keywords (let, type, match and function being the main ones) and the standard assortment of data structures (list, array, tuple, record). I think the best quick introduction to the language is Ocaml For Scientist Chapter 1 combined with Ocaml for Experienced Programmers. Overall I was impressed with Ocaml. Although it sells itself as a functional programming language, the language does have imperative constructs (when you absolutely positively need a for loop). It also has a good number of libraries available online (Ocaml can also use CPAN, yes CPAN! as in perl. Perl4Caml. I haven’t tried it though YMMV). Between Haskell and Ocaml, Haskell definitely felt like the more challenging of the two languages to learn. I would still start with Haskell if I did it over again. But definitely learn both languages!