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I don't really get what's special about OCaml with these points they raise? Wouldn't almost any strongly typed language do? Wouldn't TypeScript also tick all th

I don't really get what's special about OCaml with these points they raise? Wouldn't almost any strongly typed language do? Wouldn't TypeScript also tick all these boxes? EDIT: I wouldn't choose TypeScript either for this type of use case, but not for the reasons they state, that's my point

jacquesm 11mo ago
It's the combination with concurrency that makes this a hard problem. And OCaml excels at solving that sort of problem. OCaml and Erlang are the only two languages that I'm aware of that have a really clean way of doing this, in most other languages there is always some kind of kludge or hack to make it work and at best you're going to do something probabilistic: it seems to work, even under load, so it probably is good now. Until six weeks later on an idle Tuesday the system deadlocks and you have no idea how it happened.
- internet_points 11mo ago
  What advantage does OCaml have over Haskell here? I find software transactional memory in Haskell so simple to work with that I have lost all fear of concurrency, but what am I missing out on?
  - phplovesong 11mo ago
    Its mostly about practicality. Haskell is kind of pain when you need IO, as in when you go there there is no way out. Ocaml is more practical, and less punishing (you can do IO without monads), but the most important diffrence is performance. Haskell is VERY hard to make predictable because its lazy. Ocaml is strict so general system performance is much easier to predict. But they are sibling languages in my book, while i still prefer ocaml over haskell.
    - myaccountonhn 11mo ago
      Also IMO the dev tooling is better for OCaml. Far better compile times. A big part of interacting with APIs (which I imagine Stategraph does) is just dealing with records, and working with records in Haskell is really annoying unless you bring in lenses which bring a lot of complexity.
      - phplovesong 11mo ago
        Tooling was kind of bad previously. But dune has got really good. I like the new dune developer preview thing that is still in beta. https://preview.dune.build/ https://preview.dune.build/
        myaccountonhn 11mo ago
        Wow that looks slick!
  - yodsanklai 11mo ago
    I personally find OCaml more pragmatic than Haskell. Haskell has a steeper learning curve IMHO: monads are pervasive and are hard to understand, laziness isn't a common programming pattern and it adds complexity. I find type classes confusing as well, it's not always clear where things are defined. I like that OCaml is close to the hardware, there are no complex abstractions. The module system makes it easy to program in the large (I love mli). If you avoid the more advanced features, it's a super simple language.
    - internet_points 11mo ago
      I should have specified. I wasn't asking about OCaml vs Haskell in general[0], but what advantage does OCaml have with respect to concurrency? [0] I think most people just end up post-rationalizing whatever choice they have already invested in, I know I do :) With that in mind, maybe I as a mainly-Haskell dev should instead list some things I miss from OCaml: faster compile times, non-recursive `let` by default, polymorphic variants, labeled arguments
gregwebs 11mo ago
Functional programming is immutable by default. TypeScript and many other typed languages don't really stop you from clobbering things, particularly with concurrency. Rust does. But immutability with GC is a lot easier to use than Rust if you don't need the performance of Rust.
- galangalalgol 11mo ago
  But what is functional besides haskell? Purescript? Elm I guess. Ocaml is not. It has for loops even. You can write pure functional ocaml but people don't. It mattered a lot less when it didn't have true concurrency, but now clobbering things in ocaml is quite possible.
  - greener_grass 11mo ago
    Define functional? Even Haskell is not functional in the strictest sense. It has unsafe IO. It can throw exceptions. Functions may not halt.
    - galangalalgol 11mo ago
      Fair. Agda, gallina, f* maybe? My point was that without any escape hatches or magic you can code a segfault starting in ocaml5. That may be true of haskell? It is true of rust too, though the only known way to do it isn't something that is likely to happen by accident and is tracked as a bug. In ocaml5 if you use domain, it is down to experience skill, and some luck to be sure you used atomic when necessary. I'm a bad programmer despite going on four decades of experience. I'm not even remotely methodical. If I adopt ocaml for a project I'm using 4 or adding something that fails the pipeline if it finds domain anywhere.
      - greener_grass 11mo ago
        Shouldn't most application programmers in OCaml be reaching for EIO or some other well-tested abstraction?
greener_grass 11mo ago
• Stategraph manages Terraform state, so correctness isn't optional TypeScript has soundness issues that OCaml does not have • Strongly-typed data structures catch field errors at compile time TypeScript does have this, although the guarantees are in practice weaker since libraries may have incorrect type definitions • Type-safe SQL queries prevent schema drift before deployment There are TypeScript libraries that offer this, so fair point! • Immutability by default eliminates race conditions TypeScript is not immutable by default • PPX generates correct JSON serialization automatically TypeScript does not have an equivalent to PPX infrastructure AFAIK. If there is, it's definitely not as widely used within the ecosystem compared to PPX for OCaml. Edit: Downvoters care to respond?
IshKebab 11mo ago
OCaml has a much stronger type system than Typescript. The real question is "why not Rust?". I've used both a fair bit and OCaml's only major advantage IMO is compile time. That doesn't seem compelling enough to put up with the downsides to me.
- toolslive 11mo ago
  Ocaml has a garbage collector. It's less of a struggle than Rust.
- jitl 11mo ago
  Rust is a pain
- sausagefeet 11mo ago
  I'm the CTO of Terrateam. For "why not rust", I have found the downsides of Rust not compelling enough to use it. We don't need close-to-metal performance. We don't really need the borrow checker, a GC is fine. We are immutable by default so the borrow checker doesn't help much there.
  - pjmlp 11mo ago
    Great choice by way, I feel too many reach out for Rust, because they lack the perspective ML type systems are not something introduced by Rust, rather a long linage of languages since ML/Standard ML.
    - sausagefeet 11mo ago
      The sense I get from some comments is that if you need a type system and to compile to an executable, Rust is the only option, otherwise you can use pretty much anything. But, as you say, MLs have been compiling to binaries for decades. One of the first online books on OCaml is for systems programming. I know that isn't everyone's view, but I do hope posts like this, even if not technicaly deep, at least let people know that there are lots of options out there.
    - 11mo ago
sausagefeet 11mo ago
Certainly there are specifics between the type systems that differentiate. TypeScript generally chooses to enforce types in an ergonomic way whereas OCaml chooses to enforce types in a sound way. Whether or not that is a meaningful differentiator for someone is up to them. This blog post shows the elements of OCaml that motivate us to use it. Is it complete? No. Maybe it should be more explicit that we like using OCaml, and these technical aspects aren't unique but certainly benefits we see.
pjmlp 11mo ago
Besides the better type system, OCaml is a compiled language, you don't need workarounds like rewriting code in Rust and Go, as it happens on TypeScript/JavaScript world.
phplovesong 11mo ago
Typescript (javascript) is kind of a joke compared to what ocaml brings to the table. Ocaml has a top in class typesystem, a "faster than Go" compiler and (in 2025) good tooling. It allows you to say fuck it and write a while loop if you need to. Hell you can even do OOP. Also it has an incredible module system and full type inference. It also has an effect system, and good concurrency features (ocaml 5). I cant say many other languages that has all the same features.

jacquesm 11mo ago

It's the combination with concurrency that makes this a hard problem. And OCaml excels at solving that sort of problem. OCaml and Erlang are the only two languages that I'm aware of that have a really clean way of doing this, in most other languages there is always some kind of kludge or hack to make it work and at best you're going to do something probabilistic: it seems to work, even under load, so it probably is good now. Until six weeks later on an idle Tuesday the system deadlocks and you have no idea how it happened.

internet_points 11mo ago
What advantage does OCaml have over Haskell here? I find software transactional memory in Haskell so simple to work with that I have lost all fear of concurrency, but what am I missing out on?
- phplovesong 11mo ago
  Its mostly about practicality. Haskell is kind of pain when you need IO, as in when you go there there is no way out. Ocaml is more practical, and less punishing (you can do IO without monads), but the most important diffrence is performance. Haskell is VERY hard to make predictable because its lazy. Ocaml is strict so general system performance is much easier to predict. But they are sibling languages in my book, while i still prefer ocaml over haskell.
  - myaccountonhn 11mo ago
    Also IMO the dev tooling is better for OCaml. Far better compile times. A big part of interacting with APIs (which I imagine Stategraph does) is just dealing with records, and working with records in Haskell is really annoying unless you bring in lenses which bring a lot of complexity.
    - phplovesong 11mo ago
      Tooling was kind of bad previously. But dune has got really good. I like the new dune developer preview thing that is still in beta. https://preview.dune.build/ https://preview.dune.build/
      - myaccountonhn 11mo ago
        Wow that looks slick!
- yodsanklai 11mo ago
  I personally find OCaml more pragmatic than Haskell. Haskell has a steeper learning curve IMHO: monads are pervasive and are hard to understand, laziness isn't a common programming pattern and it adds complexity. I find type classes confusing as well, it's not always clear where things are defined. I like that OCaml is close to the hardware, there are no complex abstractions. The module system makes it easy to program in the large (I love mli). If you avoid the more advanced features, it's a super simple language.
  - internet_points 11mo ago
    I should have specified. I wasn't asking about OCaml vs Haskell in general[0], but what advantage does OCaml have with respect to concurrency? [0] I think most people just end up post-rationalizing whatever choice they have already invested in, I know I do :) With that in mind, maybe I as a mainly-Haskell dev should instead list some things I miss from OCaml: faster compile times, non-recursive `let` by default, polymorphic variants, labeled arguments

gregwebs 11mo ago

Functional programming is immutable by default. TypeScript and many other typed languages don't really stop you from clobbering things, particularly with concurrency. Rust does. But immutability with GC is a lot easier to use than Rust if you don't need the performance of Rust.

galangalalgol 11mo ago
But what is functional besides haskell? Purescript? Elm I guess. Ocaml is not. It has for loops even. You can write pure functional ocaml but people don't. It mattered a lot less when it didn't have true concurrency, but now clobbering things in ocaml is quite possible.
- greener_grass 11mo ago
  Define functional? Even Haskell is not functional in the strictest sense. It has unsafe IO. It can throw exceptions. Functions may not halt.
  - galangalalgol 11mo ago
    Fair. Agda, gallina, f* maybe? My point was that without any escape hatches or magic you can code a segfault starting in ocaml5. That may be true of haskell? It is true of rust too, though the only known way to do it isn't something that is likely to happen by accident and is tracked as a bug. In ocaml5 if you use domain, it is down to experience skill, and some luck to be sure you used atomic when necessary. I'm a bad programmer despite going on four decades of experience. I'm not even remotely methodical. If I adopt ocaml for a project I'm using 4 or adding something that fails the pipeline if it finds domain anywhere.
    - greener_grass 11mo ago
      Shouldn't most application programmers in OCaml be reaching for EIO or some other well-tested abstraction?

greener_grass 11mo ago

• Stategraph manages Terraform state, so correctness isn't optional TypeScript has soundness issues that OCaml does not have • Strongly-typed data structures catch field errors at compile time TypeScript does have this, although the guarantees are in practice weaker since libraries may have incorrect type definitions • Type-safe SQL queries prevent schema drift before deployment There are TypeScript libraries that offer this, so fair point! • Immutability by default eliminates race conditions TypeScript is not immutable by default • PPX generates correct JSON serialization automatically TypeScript does not have an equivalent to PPX infrastructure AFAIK. If there is, it's definitely not as widely used within the ecosystem compared to PPX for OCaml. Edit: Downvoters care to respond?

IshKebab 11mo ago

OCaml has a much stronger type system than Typescript. The real question is "why not Rust?". I've used both a fair bit and OCaml's only major advantage IMO is compile time. That doesn't seem compelling enough to put up with the downsides to me.

toolslive 11mo ago
Ocaml has a garbage collector. It's less of a struggle than Rust.
jitl 11mo ago
Rust is a pain
sausagefeet 11mo ago
I'm the CTO of Terrateam. For "why not rust", I have found the downsides of Rust not compelling enough to use it. We don't need close-to-metal performance. We don't really need the borrow checker, a GC is fine. We are immutable by default so the borrow checker doesn't help much there.
- pjmlp 11mo ago
  Great choice by way, I feel too many reach out for Rust, because they lack the perspective ML type systems are not something introduced by Rust, rather a long linage of languages since ML/Standard ML.
  - sausagefeet 11mo ago
    The sense I get from some comments is that if you need a type system and to compile to an executable, Rust is the only option, otherwise you can use pretty much anything. But, as you say, MLs have been compiling to binaries for decades. One of the first online books on OCaml is for systems programming. I know that isn't everyone's view, but I do hope posts like this, even if not technicaly deep, at least let people know that there are lots of options out there.
  - 11mo ago

sausagefeet 11mo ago

Certainly there are specifics between the type systems that differentiate. TypeScript generally chooses to enforce types in an ergonomic way whereas OCaml chooses to enforce types in a sound way. Whether or not that is a meaningful differentiator for someone is up to them. This blog post shows the elements of OCaml that motivate us to use it. Is it complete? No. Maybe it should be more explicit that we like using OCaml, and these technical aspects aren't unique but certainly benefits we see.

pjmlp 11mo ago

Besides the better type system, OCaml is a compiled language, you don't need workarounds like rewriting code in Rust and Go, as it happens on TypeScript/JavaScript world.

phplovesong 11mo ago

Typescript (javascript) is kind of a joke compared to what ocaml brings to the table. Ocaml has a top in class typesystem, a "faster than Go" compiler and (in 2025) good tooling. It allows you to say fuck it and write a while loop if you need to. Hell you can even do OOP. Also it has an incredible module system and full type inference. It also has an effect system, and good concurrency features (ocaml 5). I cant say many other languages that has all the same features.