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8 months of OCaml after 8 years of Haskell in production

Dmitrii Kovanikov on December 16, 2023

I've been using Haskell in production for 8 years. I've been using OCaml in production for 8 months. It's time to compare those two languages. ...

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Sam • Dec 28 '23 • Edited

Nice post. I actually previously interned at Bloomberg (though not on an OCaml team) and most recently at another company using OCaml, and I'm a big fan of the language.

I agree with most of your points, though I think your OCaml examples on the point of tacitness are a bit unidiomatic and make the difference seem larger than it actually is.

For example, with your exponentiation function, in the OCaml codebases I've seen it would be much more likely for this to be written using a match statement, making it essentially the same as Haskell in terms of concision:

let rec pow base power = match power with
  | 0 -> 1
  | n -> base * pow base (n - 1)

Or even making use of = function:

let rec pow base = function
  | 0 -> 1
  | n -> base * pow base (n - 1)

(Of course ignoring the point that an exponentiation function would never actually be written this way)

Dmitrii Kovanikov • Dec 28 '23

Thanks! I hope you enjoyed your time at Bloomberg 🤗

Indeed, this particular example could be written better with the usage of pattern matching. I wanted to show the difference between guards and if-then-else. But looks like this particular example is not that convincing.

I'll change it to a better one when I come up with it!

Meanwhile, you might have some other example in mind?

Yawar Amin • Dec 29 '23

If we are comparing succinctness, let me offer an alternative parsing example :-)

let parse_line line =
  Scanf.sscanf line "Status: %d | Result: %d" (fun status result ->
    if status = 0 && result mod 2 = 0 then Some result else None)

Dmitrii Kovanikov • Dec 29 '23

Good example! I often forget OCaml has sscanf too as well as printf 😅

Daniil Baturin • Dec 31 '23

To.ml: A TOML parser

I was so infuriated by that library that I made one to fix all its problems. ;)
github.com/dmbaturin/otoml/

It's actually compliant with the TOML standard, uses transparent types (but also offers helpers for getting nested values), and uses functors to allow the user to plug any datetime and bignum libraries or stick with built-in native int and string dates.
Well, and offers informative parse errors, too.

Dmitrii Kovanikov • Jan 9

Hey @dmbaturin

I was informed that ez_toml is better than otoml:

discuss.ocaml.org/t/8-months-of-oc...

Do you have a comparison with this library somewhere?

Dmitrii Kovanikov • Jan 2

Thanks for letting me know! Your library looks great, I'll update the link 🔗

ふわふわのうさぎ • Dec 28 '23

I follow you on twitter and saw your recent posts about ocaml, so I decided to actually try it out. Using it for a bit during the holidays made me feel like it's just worse Haskell. When I saw your post, I thought that I'd see some features that are amazing, while it might just be my viewpoint, the stuff you're showing me here makes me want to use Haskell even more.
Less than language features a few of the libraries are really cool tho. I'd love to have something akin to owl (cl.cam.ac.uk/~lw525/owl/chapter/pl...)

Dmitrii Kovanikov • Dec 28 '23

It's totally fine to have different preferences!

If you enjoy using Haskell, you can continue using it 🤗

Hercules Lemke Merscher • Jan 21

Awesome post!

I tried OCaml many years ago. I think around the same time I started playing with Haskell, but gave up on OCaml due the fact that Haskell felt more pleasant to use. You definitely made me wanna try OCaml again :)

Dmitrii Kovanikov • Jan 24

I'm glad my post was inspiring enough 😊

Escherial • Dec 28 '23

You forgot the best asset OCaml which is its Web framework. Ocsigen is the most advanced web development framework. It's revolutionary once you get how it works. Nothing else can compete, in any language.

Dmitrii Kovanikov • Dec 28 '23

I never tried Ocsigen. I guess, it's hard to compare two languages fully because you can never try everything.

But you reply gave me some motivation to try it 👀

Jay Lee • Jan 21

I’ve been using OCaml for 4 years now, but never used Ocsigen for web development. I have some experience with ReScript with React tho. I’m really curious about using OCaml for both front/backend; why would you recommend Ocsigen (vs something like Dream)

Eric Torreborre • Dec 28 '23

Nice article. It's great to have the two languages side by side as I'm tempted to have a closer look at OCaml.

Dmitrii Kovanikov • Dec 28 '23

Thanks!

Yes, I really wanted to compare these two languages.

You can find other blog posts comparing Haskell and OCaml (some are older, some are newer). But I wanted to provide my take anyway and share my experience 😌

Dmitrii Kovanikov • Jan 8

I received tons of feedback on my OCaml vs Haskell blog post! Thanks a lot to all who read and shared their thoughts 🤗

Using the feedback, I improved my post by:

✍️ Changing the most triggering exponentiation example to a different one
✍️ Added links to all discussions of my blog post all around the Internet
✍️ Changed feature from 'Laziness by default' to 'Composable laziness'
✍️ Added 'topiary' as an OCaml formatter
✍️ Changed the suggested TOML library from 'To.ml' to 'otoml'
✍️ Changed the suggested AWS library from 'ocaml-aws' to 'awsm'

Hope you enjoy it!

Bart • Jan 8

Terrific post!

For the comparison table, possibly include records support. This has been a Haskell deficit for decades, and no thank you, lenses are a bloated, heavyweight bolt-on when you just want simple, lightweight record support.

Dmitrii Kovanikov • Jan 8

Thank you!

Haskell kinda has a better record story nowadays. You can actually have nice records in Haskell without using lenses!

Anthony Alaribe • Dec 28 '23

Lovely article! I look forward to trying out ocaml as well.
It's tradeoffs seem a lot like Go. Fast compile times, minimal syntax and moving parts,

Dmitrii Kovanikov • Dec 28 '23

Thanks! I think you'll enjoy OCaml 🤗

I do see it like Go of FP languages. Which is kinda the best of both worlds 😉

Pablo Bollansée • Dec 28 '23

Great article! Really nice to see you're enjoying OCaml, I've been looking at it too, but have not actually used it yet, but this makes me even more interested in trying it out.