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Comment by ronnier | Hacker News Reader

Why would a company use ocaml?

I’ve worked in software now for most of my life, from small to the biggest companies. I’ve watched teams with senior developers use non mainstream languages to build services and just about every time those devs get board again, leave the team, leaving them stuck with this system that’s hard to develop and different from the rest of the orgs, eventually resulting in a complete rewrite.

At companies I try to be boring, not weird, and efficient. Which usually means for me, writing in a very mainstream language that is easy to hire for.

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A language like ocaml excels when the input and output are program-like, and the problem can't be number-crunched by hardware. The typical example would be a compiler. Other examples would be model checkers, code generators for number crunching libraries, proof assistants, and so on. Complex problems, where you need to explore different avenues of approach quickly, and where symbolic manipulation is at the heart of the problem.

Thus, ocaml is best used as a "kernel" or "module". The contextual part of your system uses the part written in ocaml as a service.

But ocaml doesn't excel at problems which are common to a typical company. The people who are in the intersection of wanting to solve those problems, and ocaml developers are few. The same intersection with a more mainstream language is far larger.

However, if you find yourself with a problem at which ocaml excels, chances are the mainstream languages ends up falling short very quickly, because they tend to lack the abstraction features necessary for correctly handling the complexity.

The question is if modern versions of popular languages (java, c#) caught up on ocaml's syntax sugar, or maybe this syntax sugar is trivially replaceable by some utility functions.

Maybe you could bring any example of such ocaml functionality?

Syntax and sugar is subjective, right? Instead, easier to discuss the layer beneath syntax, and that’s to compare the type systems. Java now has some version of sum types aka algebraic data types, but because of its beginnings, it may never feel as easy to use. And ease of use is important, as is evident from discussions here.

Had to look up to see where Java is at for sum types. First link I found. https://sfietkonstantin.github.io/2021/09/03/Java-sum-type.h...

sum types is not something supercritical, it saves few lines of code.

Also, somehow I rarely have need to use something like that personally.

> And ease of use is important

the question is if insignificant syntax sugar worths switching to unpopular platform with undeveloped toolings and uncertain support.

Sum types save more than a few lines of code, they can save you from nasty bugs thanks to exhaustiveness checking in pattern matches. Once you get used to this you will be hard pressed to go back to prehistoric times.

> Sum types save more than a few lines of code, they can save you from nasty bugs thanks to exhaustiveness checking in pattern matches.

do you have specific example?

Look at this code which prints out an HTML tag: https://github.com/yawaramin/dream-html/blob/main/lib/dream_...

Initially you might think generating HTML tags from data structures in code should be a simple matter. But there are complexities--some tags are defined as having no child tags, others do. Some tags are purely character data (unstructured text), not structured data. Some are just comments. We need a way to compose multiple tags together into a single 'virtual' tag for flexible HTML generation. All these conditions can be pretty hard to keep track of--unless your compiler does exhaustiveness checking. Then the compiler will tell you if you missed any cases.

In the example above I didn't make any manual effort to cover all the cases, I simple listed out the cases I wanted to handle in order. The compiler made sure that I didn't miss any.

This is very specific case though.

Many times compiler tooling will do just fine with good old visitor patterns, enums etc..

Sure there may be small amount of errors missed, but that's not always as critical as availability of libraries and integration.

Back when I tried it, there seemed to be a few verticals where Ocaml abstractions made Ocaml very productive to work with.

Once a colleague and I did a programming race between two languages, to see how long it would take to implement a small cryptanalysis program using Ocaml vs C++. I wrote it in a day, and it took my desk neighbor who was doing the same in C++ a couple of weeks.

What made the difference: - There were a lot of things I didn't have to worry about. For example, I was working with nontrivial structures but didn't have to write any boilerplate functions for deep equality or lex ordering. - Immutable structures with GC made it much more direct to translate the math into a working program. Ditto with guaranteed tail recursion optimization. - The match syntax caught many issues at compile time by forcing me to reason about every case. As a result I had many less runtime bugs to deal with, while my colleague needed to troubleshoot memory and correctness issues half the time.

Ymmv. This was for research and didn't end up in production use. The C++ implementation was also much "closer to the metal" so was able to wring out more performance. Still the difference in initial velocity was striking and there could've been a case that this would've been a better choice based on dev velocity in that vertical.

.. that's a complaint for all new languages. You don't know which ones will stick until you try.

Code in a strongly-typed functional language is easier to maintain because of the features of the language. The functional part gives great abstraction, and the strongly-typed part gives enough structure to make the whole thing tractable.

Absolutely agreed. I'm lucky to work on a ReasonML front-end codebase and the type system and immutability are a real pleasure to work with. The strong typing lets you code against the compiler, and there are many instances of "if it compiles it works" that crop up throughout development. There's no fear of refactoring code that you didn't write, because the compiler will warn you about consequences on the far end of the codebase that you didn't even know existed.

As a result of all of that, the app feels very solid to use and has comparatively few runtime errors.

Very cool to hear. I've been using rescript some recently and was hoping for exactly that sort of benefit.

I have a mixed opinion of ocaml itself having used it professionally a moderate amount. But one thing I can't deny is that ocaml programs seem to "age" better than any other languages, even other strongly typed languages.

> Why would a company use ocaml?

PG claims using Lisp was the "secret sauce" to his early success. Whether this is true or not, and whether this is still true for companies today, remains to be seen. But it's an argument for things like OCaml.

It won’t really answer your question, but I found the Signals & Threads podcast fantastic, and it made me appreciate OCaml much more (it is produced by someone working at Jane Street).

I personally found the MirageOS, build systems and language design episodes terrific.

OCaml is pretty much the most "boring", "mainstream" language that isn't awful. It's been around for decades. It's got an established library ecosystem, development tools and all that. And pretty much every bigger/more popular language is missing one or more basic feature that's been common-sense since the late '70s (e.g. sum types or pattern matching).

I'm sure some companies out there might find a competitive advantage for using exotic languages and tech stacks.

But I get the impression the more common scenario is that the engineers were bored and given the chance, wanted to play with something new and shiny.

It also depends on the company's prestige. A company like Jane Street using OCaml? Considering both their prestige and the amount they pay, I'm sure they will have no problems hiring. Nor will their alumni have problems getting hired elsewhere.

Some no name startup or even some "innovation lab" inside a boring cludgy Fortune500? Yeah, no thanks.

Jane Street wasn't all that prestigious when they started using OCaml. The way they put it is "it was easier to find great programmers in the empty set of people who know OCaml than in the huge set of other programmers" (roughly). So, on the contrary, I think it might help boring cludgy company find quality talent.

I think there is a fallacy being repeated in this thread, namely that the choice is between mainstream and weird, or between old-and-tested and new-and-shiny. No, that's not the choice. The choice is between tools and abstractions that are helpful and productive, and those that aren't. Some of the helpful and productive things are old, some are new, some are mainstream, some are niche.

I don't fully understand how someone wants to spend their career in programming and not actively seek out what is helpful and productive, rather than what currently gets the most questions on Stack Overflow or has a big pool of people who put it on their CV. It's not like all languages are equally good. It's a wasteful approach.

There's another aspect, which myself and a few others in this thread have mentioned - hireability. Both from the company's and employee's perspective.

I'm pretty sure Jane Street would have paid well even when they were an obscure name.

Will boring cludgy Fortune500 company or noname startup pay well for someone to come use an exotic tech stack that is used very rarely at any other companies? Likely not.

Likewise, would an engineer well versed in some exotic language, and can land offers at top companies, come work for a boring cludgy Fortune500 company that is only willing to pay a fraction of what they can get elsewhere?

Maybe if you've already made your fortune elsewhere and well on the road to FIRE, and are really just looking for interesting work regardless of pay.

So are you saying that Jane Street more or less bribed people who didn't really care for OCaml to come work in a weird language, by offering a good salary? I find that far-fetched, and there are many other examples of companies attractive highly-competent people because they choose -- no, not exotic, weird, or niche tech, but good tech, that aid people thinking more clearly and abstracting better.

As in everything else, there is a trade-off involved here of course. And what is truly good and helpful is by no means obvious, and might take time to assess.

"Bribed" is a crude way to describe it, but in a manner of speaking, yes?

I think you might be a tad idealistic, and you might think I'm being a tad cynical. Maybe the truth is in the middle somewhere.

But throwing enough money at someone can talk. And not throwing enough money at someone can also talk. Short of being asked to do something unethical or illegal, what's wrong with that?

Can you honestly say all of the talented top engineers out there working for top paying companies are doing it for the pursuit of technological perfection, and aren't doing it at least partially for the good money?

I would say the same thing about doctors - people all love to say you should not get into medicine for money, but can we honestly say money isn't at least a factor in whether someone decides to pursue a MD?

Ron Minsky of Jane Street has explicitly said, many times, that their choice of OCaml attracted great developers who wanted to work with it.

> I think you might be a tad idealistic

Agreed :)

"Helpful and productive" is highly context dependent. There are many tasks for which Ocaml is great at, and also many tasks for which there are much better choices available.

I worked on a team using Haskell at Target for a few years and we had a massively easier time hiring compared to the other data science/ML teams. I figure it came down to two things:

1. People are actively interested in using Haskell and working with others interested in Haskell/PL/FP/etc. More people want to do Haskell than there are Haskell jobs and Haskell openings get massive word-of-mouth advertising.

2. It's a way to show that we're willing to do something different and interesting. Everybody says they are, but how do you actually demonstrate it? I remember one of the first great hires we had was an OR professor who didn't even know about Haskell—but joined in part because what we were doing was different and innovative.

If I ever end up starting my own company, I'm going to use Haskell because it's so much easier to hire for it—completely opposite to the superficial "common knowledge" that guides executive decisions at large companies.

MirageOS and microkernels.

> Why would a company use ocaml?

Why wouldn't a company use Brainfuck?

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