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Comment by jddj | Hacker News Reader

Almost there, but in the meantime supporting a casual squillion dollars of trades at JS

Yes and they had to basically build their own version of the compiler to keep everything from falling over (https://oxcaml.org/).

This is the wrong interpretation of the oxcaml project. If you look at the features and work on it, it's primarily performance or parallelism safety features.

The latter going much further than most mainstream languages.

> Our hope is that these extensions can over time be contributed to upstream OCaml.

Yeah, its more just extensions to support their use cases at scale. Think of it more as bleeding edge ocmal, once they work out kinks/concerns they'll get merged back into the language OR if it remains ultra specific it'll stay in oxcaml.

Not a complete own version lol

Yes but the context of the thread is OCaml being "almost there". Having to build this stuff in-house is pretty good evidence.

Evidence of what?

The main user has been writing extensions to the compiler that they test before pushing for integration like they have done for the past twenty years or so. They publish these versions since last year.

Hardly a failure and certainly not something mandatory to keep things from failing over. Your initial comment is extremely disingenuous.

I don’t know about that.

Python gets forked in other investment banks as well. I wouldn’t say that is evidence of any deficiencies, rather they just want to deal with their own idiosyncrasies.

See https://calpaterson.com/bank-python.html

A different perspective is that JS has made practical application of PLT part of their secret sauce, and deepening into their PLT roots is thickening the sauce.

Yeah, but when these things happen I ask myself, is Jane Street successful because of ocaml, or did they just happen to pick ocaml and then make it work?

There might be some power in attracting all the people who happen to love ocaml, if there are enough of competent people to staff your company, but that's more a case of cornering a small niche than picking on technical merits

Clearly Jane Street wouldn't be where it is, a top proprietary trading firm in US, without static type checking.

They've spoken about this before and might not have picked OCaml if they had to make the decision again today. I think at the time it made the most sense.They can also make it work in any language as they claim to only recruit the best and brightest in the world (this may be the truth). My opinion is they could have chosen many languages and had similar results while balancing different trade-offs.

Regarding attracting talent, they've said they don't care about existing knowledge of OCaml as the language part is something they train staff on anyway. Their interviews are brutal from what I recall. I could be an OCaml expert and have no chance of making it through an interview without equal talent in high performance fintech and relevant mathematics.

> I could be an OCaml expert and have no chance of making it through an interview without equal talent in high performance fintech and relevant mathematics.

Unless their hiring process has changed in the past few years, if you're a dev they're not hiring you for your financial skills, just general problem solving and software development ability. It is (was?) the usual Google-style algorithms/data structures rigamarole, but somewhat more challenging.

Do those devs actively use OCaml? I thought most of the folks writing OCaml were writing the actual trade algorithms as opposed to infrastructure folks. My post was made off what I recall their lead technologist saying.

Absolutely. Everyone uses OCaml at Jane Street; pretty much everything at Jane Street is OCaml. If an OCaml version of something doesn't exist, there's a decent enough chance that they'll write it themselves rather than resort to a non-OCaml solution.

Like I said, my information might be a hair out of date, but it's first-hand.

Gotcha. Mine is just some old blog posts and a long talk from the guy that got OCaml started. Nothing like your actual first person experience. Thanks for adding!

Yes, everybody in JaneStreet is expected to be able to use Ocaml, Neovim, and R/Julia/etc.

Everybody in the company is expected to be able to sling numbers in text on a computer super efficiently.

They also build custom emacs tooling

Unless you're building another JS, it'd be nice if there were other companies so heavily invested in it. There's a lot out there beyond compiler prototypes and high speed financial trades, but there's not enough talk of people using ocaml for those things.

Ocaml was (historically, at least) used by Facebook for basically all of their linter/compiler/type checker work. The hack checker was in Ocaml, as was the JS thing (flow, maybe?).

So that does seem to be a good use-case for the language.

That was why I mentioned compilers along with HFT. Rust was originally an ocaml based compiler too.

I don't build HFTs and my compilers are just for fun. None of my day jobs have ever been a situation where the smaller ecosystem and community of ocaml was offset by anything ocaml did better than the selected options like .net, Java, go, rails, C or anything else I've touched. Heck, I've written more zig for an employer than ocaml, and that was for a toy DSL engine that we never ended up using.

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