melange VS reason

Hey HN, at Ahrefs we have been working on an online book that hopefully helps React developers get up and running with Melange, an OCaml to JavaScript compiler. You can read more about Melange here: https://melange.re/.

There are still a few chapters that we'd like to add before considering it "complete", but it might be already helpful for some folks out there, that's why we decided to publish it early.

The book uses Reason syntax to implement React components using ReasonReact components. You can read more about both in:

https://reasonml.github.io/

In my previous post on trying to use the NextJS App Router and Reason I described some of the problems and limitations of their compatibility with one another. With the release of Melange 2 I decided to see if the new features of Melange 2 could help to increase the compatibility of Reason and the NextJS App Router. I have also documented some of the things learnt after trying Melange (v1) with Astro and Remix.

So it's Reason, not ReasonML which the umbrella project's name, and Rescript is a imcompatible syntax split from the Bucklescript team (that previously transpiled Reason to JS). Bucklescript's new name is... Rescript.

But not everyone agrees with the split and work is being done on Melange to replace Bucklescript : https://github.com/melange-re/melange

Ultimately JsOfOcaml can directly transpile Ocaml to JS.

In reality, most folks that developed BuckleScript frontends with ReasonML switched to ReScript syntax and are happy with it. Some felt more friction because of their reliance on PPXes or FP-heavy libraries (like Relude) and those people tend to use the Melange fork of BuckleScript or they switched to js_of_ocaml.

There is a fork of ReScript that supports ReasonML syntax and with the goal of maintaining Ocaml compatibility: https://github.com/melange-re/melange.

There's also a fork of BuckleScript/ReScript called Melange that guts its build system so that instead of using ninja, it works with more standard tools for the ecosystem, specifically dune and esy. In doing so they managed to also finally get the compiler off of OCaml 4.06: now it can use a newer OCaml compiler and take advantage of four years worth of language and compiler improvements.

For OCaml and ReasonML your options are js_of_ocaml (mentioned here in ReasonML docs) or a fairly new fork of BuckleScript called melange. They differ in implementation and output, with JSOO taking intermediate bytecode generated by ocamlc and turning it into unreadable JS, vs Melange being a patched compiler that builds more human-readable JS.

I wish they would update their blog![0] The last post is from Aug. 2018, which definitely gives the impression that the project is dead.

But it's not dead, if you look at their GitHub.[1]

[0] https://reasonml.github.io/blog/

[1] https://github.com/reasonml/reason

OCaml makes so much sense to me -- it's just a shame that the syntax has some weird decisions.

I wish ReasonML (https://reasonml.github.io/) would come back -- it's a new syntax for the same language, kind of an Elixir/Erlang thing.

Ocaml is still a wonderful language if you want to look into it, and Reason is still going strong as an alternate syntax for OCaml. With either OCaml or Reason you can compile to native code, or use the continuation of BuckleScript now called Melange.

Hey HN, at Ahrefs we have been working on an online book that hopefully helps React developers get up and running with Melange, an OCaml to JavaScript compiler. You can read more about Melange here: https://melange.re/.

There are still a few chapters that we'd like to add before considering it "complete", but it might be already helpful for some folks out there, that's why we decided to publish it early.

The book uses Reason syntax to implement React components using ReasonReact components. You can read more about both in:

https://reasonml.github.io/

ReScript is "Fast, Simple, Fully Typed JavaScript from the Future". What that means is that ReScript has a lightning fast compiler, an easy to learn JS like syntax, strong static types, with amazing features like pattern matching and variant types. Until 2020 it was called "BuckleScript" and is closely related to ReasonML.

This tracks with how I've seen "normal" languages converge on similar, flawed imitations of better type systems through tools and repurposed syntax. Thank you for confirming.

Do you have any recommendations or warnings regarding general languages which reach in the opposite direction? Reason[1] and F#[2] are both examples: they attach pre-existing ecosystems and compile-for-$PLATFORM tools to OCaml-like typing.

OCaml itself is also intriguing for personal projects. However, I'm worried the "GPL" in its standard library's LGPL license might scare people despite both the linking exception and Jane Street's MIT alternative.

1. https://reasonml.github.io/

ReasonML purely as a syntax layer on top of OCaml is still being updated and released[1]. Incidentally, I'm one of the maintainers of that project too :-)

With this Melange release, we're hoping to somewhat revive ReasonML and channel some folks back to the community from the perspective of a vertically integrated platform that has seen major investment in the past few years.

[1]: https://github.com/reasonml/reason

Why not use https://reasonml.github.io/ instead? Or just use Typescript?