Merge branch 'add-nix-flake'

.github/workflows/nix.yml

@@ -0,0 +1,25 @@
+name: Nix
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    name: Nix Flake - Linux
+    permissions:
+      contents: read
+    steps:
+      - name: Install Nix
+        uses: cachix/install-nix-action@v13
+        with:
+          install_url: https://nixos-nix-install-tests.cachix.org/serve/i6laym9jw3wg9mw6ncyrk6gjx4l34vvx/install
+          install_options: '--tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve'
+          extra_nix_config: |
+            experimental-features = nix-command flakes
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+      - name: Clone project
+        uses: actions/checkout@v2
+      - name: Build
+        run: nix build

flake.nix

@@ -0,0 +1,27 @@
+# This file is maintained by @IvanMalison (github)
+{
+  inputs = {
+    flake-utils.url = github:numtide/flake-utils;
+    git-ignore-nix.url = github:IvanMalison/gitignore.nix/master;
+  };
+  outputs = { self, flake-utils, nixpkgs, git-ignore-nix }:
+  let
+    overlay = final: prev: {
+      haskellPackages = prev.haskellPackages.override (old: {
+        overrides = prev.lib.composeExtensions (old.overrides or (_: _: {}))
+        (hself: hsuper: {
+          xmonad = hself.callCabal2nix "xmonad" (git-ignore-nix.gitIgnoreSource ./.) { };
+        });
+      });
+    };
+    overlays = [ overlay ];
+  in flake-utils.lib.eachDefaultSystem (system:
+  let pkgs = import nixpkgs { inherit system overlays; };
+  in
+  rec {
+    devShell = pkgs.haskellPackages.shellFor {
+      packages = p: [ p.xmonad ];
+    };
+    defaultPackage = pkgs.haskellPackages.xmonad;
+  }) // { inherit overlay overlays; } ;
+}