Ylixir's Reasonml And Nix

The official reason docs go with installing bucklescript globally. This results in a development environment that is hard to reproduce.

Instead we are going to use nix to create a simple development environment, and keep our dependencies local and reproducable.

Set up nix

First we need to configure nix. If you don’t have nix installed, you can get it here..

You will need to create a default.nix file in your project root directory. Put the following configuration in the file.

let
pkgs = import <nixpkgs> {};
in
  with pkgs; [
    nodejs
  ]

Reason go

Now with four commands we can create a reasonml project.

#enter the development environment
nix run

#initialize our package.json
npm init

#install reason locally
npm install --save-dev bs-platform

#initialize reason boilerplate/create hello world
./node_modules/.bin/bsb -init .

Build it

Okay, now we have a start to our project with a src/demo.ml file. But it won’t build out of the box. Let’s add some convenience scripts to our package.json.

{
  "scripts": {
    "clean": "bsb -clean-world",
    "build": "bsb -make-world",
    "watch": "bsb -make-world -w"
  }
}

And now we can build and run it!

npm run build
node src/demo.bs.js

Have fun with your new Reason development environment.