Reflections on my first completed application in OCaml
discuss.ocaml.org
discuss.ocaml.org
The language however is quite nice and the stdlib is fairly complete.
Edit: Another problem I see is the (over?) reliance on PPX preprocessors. It does make a lot of tasks simpler, but it is too much magic for me personally.
What’s making the PPX situation even worse is that they seem to break with every new release of the compiler.
With PPX, the barrier to use metaprogramming has become lower (especially compared to camlp4), resulting in most modern Ocaml codebases depending on it. But the ergonomics of the end-to-end software delivery have not really followed: the fact that PPX's break between compiler versions means that in practice, a compiler upgrade becomes a very costly thing to do. It is difficult to make the case for this in an industrial setting, where languages with almost religious backwards compatibility are common (Java, C++, even Go). For Ocaml, it is especially sad, because the core language is already quite powerful and expressive, lowering the need for metaprogramming (imo).
For scenarios where code generation is needed, I prefer a separate code generation step, which produces explicit "standard" code (e.g. like protoc)
OCaml is an academic language like Haskell. Academics tend to neglect documentation in general, be it because what they're working on is mostly self-serving, lack of time/enthusiasm or a tinge of elitism on that "this should be obvious and if not just read the code".
Rust adherents seem to really want to take over the world and they realize that great documentation is an enabler for that.
Also the standard libraries and compiler set a pretty strong precedent.
It is a complete and up-to-date manual of the entire OCaml distribution, including executables, language, runtime, and standard library. It's rare to find modern industry-driven languages with this level of coherent documentation.
But regarding third-party library documentation, that is indeed spotty. Some people publish it, some don't. I have to reluctantly conclude it's due to a lack of tooling which automates the tedious processes.
Some of it can be driven by external factors: javascript was the only choice for an important domain for a long time.
Some if it I think is due to attractive syntax, or tooling. Python for example, horrible runtime performance, but people were drawn to it for probably syntax and tooling reasons.
Comparing Rust and OCaml:
The OCaml syntax is a bit odd. I was quite taken by F#, which is a very similar language to OCaml, but with some of the cumbersome syntax removed. F# seemed quite nice, looking at OCaml it just felt horrible and I didn't want to deal with it. In practice I know it would be fine, just like you get used to Lisp and it's parens, but there is a real psychology there that turns people away.
OCaml has good runtime performance, but its not the kind of language that will draw in C/C++ programmers or work for domains where you need C or C++ currently. Lack of multi-core is a huge turn off for a lot of people. This is the era where multi-core is our only path to more performance!
Rust syntax is a little more familiar to people, the runtime performance is top notch, very good at leveraging more cores, and maybe most importantly the community has made a concerted effort to make the language as approachable as possible. With good/friendly documentation and community. Easy install process, decent editor support, etc. Go ask a question about "Which way is faster" in a C# forum, you get a lecture about how you shouldn't worry about that. On a Rust forum you get an deep dive into performance concerns and language design. This seems to have drawn in people from communities you wouldn't expect. A low level, complicated language that Ruby and Javascript developers are drawn to? An interesting result!
Tooling? How so? Like the REPL? Because when I think of tooling, I think of things like IDEs, dependency management, and distribution. Python has one of those things now (IDEs/notebooks), but even that took a while, IMO.
Python is a weird case study for me. I'm not trying to flame war or anything- just pointing out my own blind spots and/or biases. But I just don't see much of anything redeeming about the language. It can be pretty easy to read, but I don't think most code I've seen actually is easy to read/follow.
care to elaborate?
Now this is not the same language/community improvement system that many popular projects nowadays use, but OCaml has been stewarded in its way for a few years now, and it's something the contributors feel is sustainable given the size of the project and the resources available.
About Unicode specifically, there is of course support at the library level as you mentioned (the most well-known library is Camomile), but to try to justify not including it in the language distribution itself, to a certain extent many applications just don't need it. Those that do can of course use libraries, but many (say, backend servers) don't really need to process Unicode strings, they just need to shovel bytes from point A to point B and not actually touch the contents.
I can't speak for actual Ocaml users, but I've personally rejected Ocaml for my user-facing webapps because of things like this. Treating unicode as something optional was fine for early 2000s, but it's really not fine today. Most user facing applications need first class support for internationalized strings much more than other stuff like Big_int that's actually implemented in Ocaml stdlib.
I'm guessing the status quo works fine for existing Ocaml users, but that's kinda circular, and would explain Ocaml's limited adoption outside of its traditional niches.
Maybe I’m just in the minority - I like the fact that there are lots of languages out there, some of which choose not to cater to every possible development scenario. This is why I know lots of languages - instead of trying to apply one to every situation, I look at a situation presented to me and can go into my mental toolbox to pull the right language out for the job. I don’t see language design/implementation as a competition to acquire users. Do a job, do it well, and some subset of people will be happy - those that aren’t can move along and continue browsing the catalog of languages until they find one that meets their needs.
* Node with TypeScript
* JVM with Scala
* CLR with F#
Language-wise, it is Ocaml with a different syntax layer, so all of the nice things about the language are still available.
- Super-fast compiler
- Readable and succinct JS output with nearly 1-to-1 mapping from OCaml source
- Simple module system with no need to explicitly import modules--the compiler takes care of it for you
- High-quality React and other bindings
- The standard advantages of the type system like expressive power of data types and pattern matching with exhaustivity checking
- Tons of super useful built-in lints like 'unused variable', 'unused function parameter', 'discarding a value', etc.
Some industrial Ocaml users use the web as a UI. I'm fairly certain Jane Street does it for exemple. That's very much user-facing web apps.
I understand that it's not something that interests you but there has been plenty of work geared towards building web applications in Ocaml (and Reason). Saying it probably won't ever be a core application target seems quite wrong.
this is a self-fulfilling prophecy
And yet OCaml is French and its French authors do not feel constrained by the lack of unicode or they would have "scratched their own itch".
Lots of Web stuff is just that (DB queries, GET/POST parameters, HTML, templating, URLs, JSON, XML, etc.). Whilst lots of that can be done via bytes, there are certainly cases where Unicode is needed (e.g. finding word boundaries, case-insensitive comparison, etc.).
Ocaml (and SML) have the enviable position of being safer+faster than scripting languages, and more approachable+familiar than the likes of Haskell (which otherwise has a similar feature set). That makes it very well suited to such domains IMHO.
I wouldn't be so sure. The way that the ReasonML and ReScript communities have been attracting frontend developers, webapps may already be the single biggest target platform for OCaml (well, a derivative) today.
This is certainly a valid argument, but honestly most languages handling of Unicode is really poor to the point where I actually prefer OCaml's not handling it since then I can use dbunzli libraries and get stuff to work correctly. Just try reversing a Unicode string and you'll see all kind of languages "with Unicode support" fail miserably, e.g reversing 🇺🇦 into 🇦🇺.
Go outside the BMP and see how nearly nobody has bothered to implement proper support for Unicode glyphs, let alone word boundaries etc. Swift might be one of the exceptions but outside of that? Bummer. Bonus points to Python 3 for breaking compatibility because of Unicode and then doing it wrong anyway.
The issues are:
* how unicode support is implemented in third party libraries: how easy it turns out to manipulate this datatype with those libraries
* how easy it is to integrate third party libraries in a project
OCaml went a long way in both accounts since the early 2000s, perhaps you should give it a second look?
And maybe they don’t want their language to be mainstream—that’s perfectly fine, but that undermines all of the arguments that this or that project should be (re)written in Ocaml or that Ocaml is otherwise a better language than $x for general software development.
There is one standard library--the one that ships with OCaml. You can use replacement libraries if you really need them--I haven't yet needed to, but for heavy-duty production use maybe one day I will.
> Where are is of the guides for building production applications?
Is the emphasis on 'building' here, as in 'build tool'? If so, then https://dune.build/ is what you need. If the emphasis is on 'production application', then I'm sure there are others but https://shonfeder.gitlab.io/ocaml_webapp/ comes to mind immediately.
> Why is the documentation so poor?
Which documentation specifically? If you mean OCaml itself, then you should check out https://ocaml.org/ , it has tons of high-quality documentation. If you mean third-party libraries, then it's probably mostly a lack of tooling that publishes docs automatically, but I think this is starting to change.
> How do the editor plugins compare to those for Go, Rust, etc?
The OCaml Language Server and its main editor plugin (for VSCode) are nearly feature-complete. The older Merlin tooling has been used for a long time.
> How familiar is the syntax to the broader body of developers?
Syntax can be learned, but for those who don't want to try, there is always ReasonML syntax that uses semicolons and curly braces to make OCaml look like JavaScript.
> I’m not saying the Ocaml community never does anything practical; only that they don’t do enough to make their language mainstream.
It's easy to make assertions without actually knowing anything, but it's better to do the research first to back them up, instead of asking a bunch of questions ;-)
You're mistaken (or you're making an unrelated semantic argument because you don't want to argue the actual point; not sure which); there are multiple "standard" libraries used across the ecosystem (because the ecosystem has deemed "the one that ships with OCaml" to be inadequate) which makes integrating libraries throughout the ecosystem tedious and painful, especially to new OCaml developers.
> Is the emphasis on 'building' here, as in 'build tool'?
No, I expect an abundance of tutorials that explain how to build production-grade applications, soup to nuts. E.g., for a generic CRUD app, what are the best frameworks, ORMs, etc to use, how to integrate them, etc?
> The older Merlin tooling has been used for a long time.
Yes, but it's incredibly difficult to configure properly, or at least that was my experience when I got started. I'm actually not sure if I ever got it working with vim.
> Syntax can be learned, but for those who don't want to try, there is always ReasonML syntax that uses semicolons and curly braces to make OCaml look like JavaScript.
It can, but it's a burden with no advantage. Last I checked, ReasonML's support was pretty abysmal--it seemed like native compilation was neglected altogether in favor of something called "bucklescript" (presumably compilation to JS) and the integrations with the rest of the ecosystem (e.g., how to build native programs, link against ocaml dependencies, integrate with editor tools, etc) were either poorly documented or inadequate/incomplete or both. No doubt some of that has improved in the intervening years, but I'm doubtful that it has significantly improved.
> It's easy to make assertions without actually knowing anything, but it's better to do the research first to back them up, instead of asking a bunch of questions ;-)
You've provided the same unhelpful, pat answers that the OCaml community provides. For example, "Just use ReasonML!" as though setting up or using Reason is trivial or well documented or otherwise comparable to using Rust or Go out of the box. For another example, you altogether dodged the issues associated with multiple "standard" libraries. It would be great if the OCaml community were as committed to making their language useful for production applications as they were on convincing everyone else that it already was.
It's both trivial and well documented. There is an installation page and a tutorial on the Reason website. The installation in itself is one npm command.
> For another example, you altogether dodged the issues associated with multiple "standard" libraries.
There is only one standard library. It's the one shipped with the compiler. It is also significantly more battery included now than it used to be.
> It would be great if the OCaml community were as committed to making their language useful for production applications as they were on convincing everyone else that it already was.
The OCaml community as a whole is one of the least vocal on the internet. It does very little outreach. I never see any of the people I consider relevant to the community on HN for example.
No one cares about convincing you that OCaml is ready for production use. It doesn't need to be argued, it can just be shown. OCaml is not an up and coming language, it's a 25 years old one. It powers a lot of Jane Street infrastructure. It is used to develop Coq and Frama-C. It is transpiled to javascript at Facebook and Bloomberg. Heck, Rust which you apparently hold dear was originally written in it.
> OCaml is at the heart of cloud computing infra. Every time you spin up an EC2 instance–its hypervisor runs OCaml code.
OK, let's examine this a bit more. There is one (two, depending on how you look at it) main competitor to the OCaml standard library: Jane Street's Core/Base libraries. JSC is a high-quality, production-grade standard library replacement meant for use in applications. However it uses the same basic types (list, array, result etc.) as the OCaml Stdlib, so I don't see where your 'integration' issues are coming from. Can you give a specific example?
> No, I expect an abundance of tutorials that explain how to build production-grade applications, soup to nuts. E.g., for a generic CRUD app, what are the best frameworks, ORMs, etc to use, how to integrate them, etc?
OK, I provided one such tutorial in my previous comment. I'm sure more will come in time, as the community is still evolving. There is also the OCamlverse wiki which tries to distill a lot of community knowledge: https://ocamlverse.github.io/
> Yes, but it's incredibly difficult to configure properly, or at least that was my experience when I got started. I'm actually not sure if I ever got it working with vim.
If you use the community recommended Dune build system to run your builds, Dune generates .merlin files automatically. And if you use VSCode with the OCaml and Reason IDE extension, it picks up on those .merlin files and provides editor support pretty much out of the box. This has been the case for at least a couple of years now.
> ReasonML's support was pretty abysmal--it seemed like native compilation was neglected altogether ... and the integrations with the rest of the ecosystem (e.g., how to build native programs, link against ocaml dependencies, integrate with editor tools, etc) were either poorly documented or inadequate/incomplete or both. No doubt some of that has improved in the intervening years, but I'm doubtful that it has significantly improved.
It's been the case for quite a while now that Dune and odoc--two main tools in the OCaml toolchain--support Reason syntax out of the box. Again, if you are using Dune, you can use Reason syntax immediately, with no special setup. This is documented.
> You've provided the same unhelpful, pat answers that the OCaml community provides.
No, I've asked you to read the documentation and do your research before making claims. Not even Rust and Go are as 'trivial' to use as you make them sound. They have all had their editor support and library issues. OCaml maintainers and contributors are trying just improve the situation in OCaml just as much as their Rust/Go counterparts. But you have to meet them partway. They can't spend massive amounts of time marketing every single OCaml ecosystem improvement--otherwise they'd have no time to make the improvements.
I was just remarking to a coworker Friday how happy this made me; you get to write nice, obvious, readable string expressions with the right substitions, for ~arbitrary types.