The NIX update

nix/macOS/flake.nix

@@ -0,0 +1,85 @@
+{
+  description = "Darwin system flake";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    nix-darwin = {
+      url = "github:LnL7/nix-darwin";
+      inputs.nixpkgs.follows = "nixpkgs";
+    }
+
+    home-manager = {
+      url = "github:nix-community/home-manager";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = inputs@{ self, nix-darwin, nixpkgs }:
+  let
+    configuration = { pkgs, config, ... }: {
+      services.nix-daemon.enable = true;
+      nix.settings.experimental-features = "nix-command flakes";
+      nixpkgs.config.allowUnfree = true;
+      system.configurationRevision = self.rev or self.dirtyRev or null;
+      system.stateVersion = 5;
+
+      # Home-manager module.
+      home-manager = {
+        extraSpecialArgs = {inherit inputs;};
+        backupFileExtension = "backup";
+        users = {
+          "trude" = import ./home.nix;
+        };
+      };
+
+      # Configs
+      environment.systemPackages = [
+        pkgs.mkalias
+      ];
+
+      system.activationScripts.applications.text =
+      let
+        env = pkgs.buildEnv {
+          name = "system-applications";
+          paths = config.environment.systemPackages;
+          pathsToLink = "/Applications";
+        };
+      in
+        pkgs.lib.mkForce ''
+        # Set up applications.
+        echo "setting up /Applications..." >&2
+        rm -rf /Applications/Nix\ Apps
+        mkdir -p /Applications/Nix\ Apps
+        find ${env}/Applications -maxdepth 1 -type l -exec readlink '{}' + |
+        while read src; do
+          app_name=$(basename "$src")
+          echo "copying $src" >&2
+          ${pkgs.mkalias}/bin/mkalias "$src" "/Applications/Nix Apps/$app_name"
+        done
+        '';
+
+      # Configure macOS
+      system.defaults = {
+        # man 5 configuration.nix
+        dock.autohide = true;
+        loginwindow.GuestEnabled = false;
+        NSGlobalDomain.AppleInterfaceStyle = "Dark";
+        NSGlobalDomain.KeyRepeat = 2;
+      }
+
+      # nixpkgs.hostPlatform = "x86_64-darwin"; # aarch64-darwin for ARM
+    };
+  in
+  {
+    # Build darwin flake using:
+    # $ nix run nix-darwin -- switch --flake ~/.config/nix-darwin
+    darwinConfigurations.default = nix-darwin.lib.darwinSystem {
+      modules = [
+        configuration
+        inputs.home-manager.nixosModules.default
+      ];
+    };
+    darwinPackages = self.darwinConfigurations.default.pkgs;
+  };
+}