Can anyone speak to the pros/cons of learning OCaml vs Haskell? They seem comparable in some respects, but it feels to me as if Haskell has more momentum and presumably a more active community. Am I correct in this assumption?
I love Haskell. Love it to death.
I see RWO as a justification of OCaml's language choices from the perspective of system deployment. It gives you a good start on the knowledge you'd need to push an OCaml system into serious production.
I do not see how to get the same knowledge for Haskell. Particularly the runtime is a black box to me. This might be acceptable for your use cases, but for me, this is the primary risk of Haskell.
re: community, It's probably true that Haskell so far is more prominent than OCaml right now, I would be careful to avoid making the mistake of assuming that this means people actually know how to deploy this for serious, scale production systems. Because it is not obvious that this is true. Besides, while the OCaml community is not as noisy, they are certainly still around.
F# is number 13; ML is number 26; Haskell is number 38; OCaml is ranked below 50.
So the ML family of languages is way more popular than Haskell, but is fragmented.
Below are my impressions/experiences.
In general, the languages themselves are excellent, but the standard libraries vary in quality, as do the tool chains. ML is eager by default, Haskell lazy. Otherwise, it's the same mindset (although some people will think Haskell went overboard on monads, some people think OCaml's libs aren't monadic enough)
For example f# is excellent in all of the above, but is _challenged_ in the multi-platform aspect.
OCaml's standard library is limited, but this is compensated with Opam. Considering OCaml on windows is simply looking for trouble. The OCaml compiler is good, but other tools are limited or a bit primitive (heap profilers, debuggers, performance profilers). The community is rather reserved, but very helpful.
Haskell standard library is also limited (for example you ain't gonna jump far with the string implementation that's offered by Prelude, and Num is also warted). The toolchain is better than OCaml's. Also Cabal has libs for everything, but ymmv. The community is really gentle and eager to help.
ML, sorry no experience, most other flavours seem dead or quiet. MLton is a really interesting compiler.
I think it's important to point out that Haskell is actually functionally pure (in that there are no side effects in the language), whereas ML does have references baked into the language, so you can revert back to writing Pascal-looking inner loops in Caml, for example.
Some might take "Haskell doesn't have side effects" to mean that you can't talk to servers or read the filesystem.
Try e.g. github http://redmonk.com/sogrady/2014/06/13/language-rankings-6-14...
I've always seen Haskell as a kind of ML off-shot, but perhaps the similarity is more in the syntax than in the substance?
Huh, I don't have a pi, but judging (blindly) by:
http://www.haskell.org/haskellwiki/Raspberry_Pi
That should be "You can run the Ocaml toplevel on the Pi"?