melange VS ninja

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.

Under the hood, Rescript uses a build system called Ninja. Ninja is similar to Make, but cross-platform and more minimal/performant.

Really? I thought most new projects were switching to ninja[^1] and have never used it.

[^1]: https://ninja-build.org/

warning: Starting with the September 2023 release, the default triplet for vcpkg libraries will change from x86-windows to the detected host triplet (x64-windows). To resolve this message, add --triplet x86-windows to keep the same behavior. Computing installation plan... The following packages will be built and installed: * egl-registry:x86-windows -> 2022-09-20 glew:x86-windows -> 2.2.0#3 * opengl:x86-windows -> 2022-12-04#3 * opengl-registry:x86-windows -> 2022-09-29#1 * vcpkg-cmake:x64-windows -> 2023-05-04 * vcpkg-cmake-config:x64-windows -> 2022-02-06#1 Additional packages (*) will be modified to complete this operation. Detecting compiler hash for triplet x86-windows... A suitable version of powershell-core was not found (required v7.2.11) Downloading portable powershell-core 7.2.11... Downloading powershell-core... https://github.com/PowerShell/PowerShell/releases/download/v7.2.11/PowerShell-7.2.11-win-x86.zip->C:\vcpkg\downloads\PowerShell-7.2.11-win-x86.zip Downloading https://github.com/PowerShell/PowerShell/releases/download/v7.2.11/PowerShell-7.2.11-win-x86.zip Extracting powershell-core... error: while detecting compiler information: The log file content at "C:\vcpkg\buildtrees\detect_compiler\stdout-x86-windows.log" is: -- Downloading https://github.com/ninja-build/ninja/releases/download/v1.10.2/ninja-win.zip -> ninja-win-1.10.2.zip... -- Configuring x86-windows CMake Error at scripts/cmake/vcpkg_execute_required_process.cmake:112 (message): Command failed: C:/vcpkg/downloads/tools/ninja/1.10.2-windows/ninja.exe -v Working Directory: C:/vcpkg/buildtrees/detect_compiler/x86-windows-rel/vcpkg-parallel-configure Error code: 1 See logs for more information: C:\vcpkg\buildtrees\detect_compiler\config-x86-windows-rel-CMakeCache.txt.log C:\vcpkg\buildtrees\detect_compiler\config-x86-windows-out.log

I thought I would share my custom installer script for the latest GitHub versions of CMake, Ninja, and Meson.

Now that you have your build system all generated you can go ahead and build everything. By default Meson will use Ninja as the build tool. Ninja is similar to Make but much much faster. You can also generate additional build systems but that's outside of the scope of this post.

There are also some other tools like https://ninja-build.org/ that you might prefer using instead

I got Ninja from https://github.com/ninja-build/ninja, latest release. I'm assuming this is a false positive?

Oh excellent, then better (and more portable!) tools are available:

http://pants.build

https://ninja-build.org

https://buck.build

and, if you hate yourself: https://bazel.build