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Comment by ubercow | Hacker News Reader

Is anyone here using Reason in any meaningful way? Even just a side project.

If so, what are you using it for and how do you like it.

Not using it, but jumping in to share an anecdote –

I saw the Reason announcement months and months ago and decided to use it as a jumping-off point into the OCaml ecosystem. It took about a week of writing Reason before I realized I was spending so much time reading OCaml (all the libraries were written in it) before I just switched to OCaml proper. Haven't looked back - the syntax takes a few days to pick up, but is hardly the most difficult part of writing a program.

Hopefully they can capitalize on the "Build" and "Share" part of their value prop [0] because "Syntax" appears (to most) to be the least valuable improvement. As a disclaimer, I could be totally wrong, never having worked at a FB-size organization – that onboarding time probably adds up quickly.

Come to think of it: can anyone think of a successful transpiled language that doesn't actually provide new semantics? Coffeescript is the closest thing that comes to mind, but it's dying out as ECMAScript absorbs its most appealing features.

[0]: http://facebook.github.io/reason/#reason

Edit: forgot about Elixir, which seems to be doing quite well – but that introduces new semantics like homoiconicity + macros and protocols.

There's some neat stuff in the Reason syntax, apart from the make-it-less-weird-for-those-coming-from-JS/Java/C#/etc., for instance: JSX[0] and named curried functions[1]. Both are fitting in really nice when doing FE dev't like with `react-reason`[2].

If you are interested in this, I recommend some talks. First one by Cheng Lou, a main contributor of Reason and FB employee on React Conf 2017[3]. And a talk by Sean Grove[4] on Reason in general.

With the power of FB behind this new techonolgy (they have currently written 25% of messenger.com in Reason), this might well become very big. A general purpose strongly typed functional prog lang, that has a vast ecosystem, now an approachable syntax, and compiles to both native and JS. Sounds good nuh?

[0]: https://facebook.github.io/reason/#diving-deeper-jsx

[1]: https://facebook.github.io/reason/#diving-deeper-curried-fun...

[2]: https://github.com/chenglou/reason-react-example/blob/master...

[3]: https://www.youtube.com/watch?v=_0T5OSSzxms

[4]: https://www.youtube.com/watch?v=8LCmLQ1-YqQ&t=517s

Can you explain how named curried functions differ from ocaml's named arguments? It looks exactly the same, other than the syntax.

They are the same. I don't think cies was implying they were different.

The wording seems to pretty clearly say otherwise, but I appreciate the confirmation that I'm not missing anything.

They're not different than OCaml's, but Reason's JSX is an interesting / useful application of labeled arguments that appeals to React developers.

My bad. They're the same (as others noted). Was not familiar with them.

> (...) Coffeescript is the closest thing that comes to mind, but it's dying out as ECMAScript absorbs its most appealing features. (...)

CoffeeScript seems to be doing well, they're working on version 2.0 (currently in alpha) aka coffeescript@next [1] with async/await (with similar approach as they did with generators where only `yield` keyword is used and the function is implicitly lifted to generator, similarly using `await` implicitly lifts function to async, so there's no need to mark function as async explicitly - very good idea IMHO), ES2015 classes and some other changes.

CoffeeScript is still what it was before - making code easier and more pleasurable to read and write: less verbose, everything is an expression, existential operator, better switch, comprehensions, prototype access operator, chained comparisons, block regex, implicit returns, range loops...

[1] http://coffeescript.org/v2/

Also note that there are some language features which are surprisingly syntactic - which are well within the scope of Reason : For example, some basic facilities for export/import as well as async transformations. These are all being discussed/proposed in the Reason channel, and they can be implemented in an opinionated syntax without needing to fragment the OCaml ecosystem - providing full interop between existing OCaml packages / tools. Once/if a build system is standardized in the OCaml community, there are even more interesting features and tools that can be built, and can be given first class syntactic treatment from within Reason.

I work alongside the Reason team. We're using it on messenger.com. 25% converted over already. 4 bugs during conversion, and only a single runtime bug in the converted part since last half.

messenger.com is written in ocaml? that's pretty neat!

Converted. From reactjs to reason-react https://github.com/reasonml/reason-react

Which imo is a bigger achievement! Being able to gradually convert a js codebase over is one of our main goals.

indeed! i would love to read a blog post about the conversion.

The front-end or back-end? The front-end isn't what I would call an endorsement of whatever framework/language is chosen.

Ooooouh that's harsh lol. Sorry for your experience. We're trying to improve it but we're a tiny team that also maintains other features.

I didn't mean to offend, and I understand. But it's 1.4mb of JavaScript that takes 4 seconds to load on my high-end Macbook.

> work alongside

Cheng, you're pretty much a full time contributor :P

messenger.com is 25% Reason

I tried using Reason for a side project. Getting the build tools and the package manager for ocaml took too long so I gave up.

If you're still willing to give it a second chance, we've got https://github.com/chenglou/reason-react-example which uses only npm Sorry for the crappy initial experience.

I did see that, but I discounted it because I wanted to make a serverside (native, not serverside-js) application, and I assumed that the reason-react-example was only for making compile-to-javascript applications.

If you'd like, I can help you get set up on Discord: http://discord.gg/reasonml

Just so we don't miss the opportunity to learn - would you mind stating what you would find valuable in a toolchain for building a server side native system? What kind of things about project management/install appeal to you?

When will ReasonML use the latest OCaml? Maybe it doesn't matter much, but it's still quite an old version.

We are compatible with 4.03 and 4.04 via opam!

That's great to hear. It's often a bad sign when base-something can't be upgraded and lags for years.

I think you need to update this page since it mentions 4.02.3 still. https://github.com/facebook/reason/blob/master/README.md#ins...

Thanks for the reminder.

The most important part of language tooling for me is reproducability. I should be able to do the following to any project:

    git clone <project name> && cd <project name>
    <build tool> build

And have it fetch all of that projects dependencies, and then build the entire system.

Anything that requires machine-wide package installation is immediately disqualified (user-wide package installation is almost as bad).

I had much the same experience. I'd be interested to try it for general purpose programming, but the setup procedure is so tied into doing web work that I couldn't figure out what I was supposed to be doing.

What's Reason's debugger story like?

Red (https://github.com/reasonml/red) provides a useable frontend to the ocaml debugger. If your code compiles with bucklescript (most code will), the debug experience using node and the chrome inspector is surprisingly good even without source maps. The compiled ocaml maps to remarkably straight forward javascript for most code. I used both while developing Immutable-re.

May I ask what you end up using?

Ended up just writing it in Rust which I've been using for years now. I wanted to try something new, it's hard to compete with Cargo for package management + build tools.

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