README.md

PureScript Overlay

Pure and reproducible overlay for the standard PureScript toolchain, including support for Nix flakes. The toolchain is auto-updated every day. Currently supported tools:

• purs, the compiler
• spago, the package manager
• purs-tidy, the code formatter
• purs-backend-es, the optimizer
• purescript-language-server, the language server protocol

⚠️ This library is unstable and may be reorganized. Use at your own risk!

The overlay is tested on the following architectures:

• x86_64-linux
• x86_64-darwin (Intel Mac)
• aarch64-darwin (M1 Mac)
• aarch64-linux

The included overlay inserts the latest stable and unstable executables into your packages (ie. purs, purs-unstable, and so on). You can see all specific versions in the named.json file. It also provides many versions of each executable under a -bin namespace (ie. purs-bin, spago-bin, and so on) so you can access specific versions of a tool. For example, you can use purs-bin.purs-0_15_8 to get the 0.15.8 PureScript compiler. These are tracked in the manifests directory.

There is also an included library named purix which provides helper functions for building PureScript packages, namely:

• buildSpagoLock: Build output directories for any package or workspace listed in a spago.lock file

Usage

In a Nix flake, use the provided overlay when importing nixpkgs to get access to tools like purs and spago and functions like buildSpagoLock. For example, the below flake creates a development shell with recent versions of the PureScript compiler and Spago package manager:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
    purescript-overlay = {
      url = "github:thomashoneyman/purescript-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = { self, nixpkgs, ... }@inputs:
    let
      supportedSystems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];

      forAllSystems = nixpkgs.lib.genAttrs supportedSystems;

      nixpkgsFor = forAllSystems (system: import nixpkgs {
        inherit system;
        config = { };
        overlays = builtins.attrValues self.overlays;
      });
    in {
      overlays = {
        purescript = inputs.purescript-overlay.overlays.default;
      };

      packages = forAllSystems (system:
        let pkgs = nixpkgsFor.${system}; in {
          default = pkgs.hello; # your package here
        });

      devShells = forAllSystems (system:
        # pkgs now has access to the standard PureScript toolchain
        let pkgs = nixpkgsFor.${system}; in {
          default = pkgs.mkShell {
            name = "my-purescript-project";
            inputsFrom = builtins.attrValues self.packages.${system};
            buildInputs = with pkgs; [
              purs
              spago-unstable
              purs-tidy-bin.purs-tidy-0_10_0
              purs-backend-es
            ];
          };
        });
  };
}

You can also run individual packages from the flake, e.g. to format your src directory:

nix run github:thomashoneyman/purescript-overlay#purs-tidy format-in-place src

Tests

You can run the repository tests using a combination of nix eval .#lib (to run the unit tests in Nix) and nix flake check (to run the derivation-based tests). Both are executed in CI.