markcode: home.nix

home.nix

@@ -1,14 +1,23 @@
+#MC # home.nix
+#MC
+#MC This file is the entry point of home-manager's config.
+#MC It imports my global options in `./opt.nix`,
+#MC my CLI configs in `./usr/cli.nix`
+#MC and my GUI configs in `./usr/gui.nix`.
+#MC The environment variable `DISPLAY` is used to determine whether to enable the GUI configs.
 { config, pkgs, stdenv, lib, ... }:
 
 {
   imports = [
     ./opt.nix
     ./usr/cli.nix
-    # TODO: how to use isGui here?
-  ] ++ (if (builtins.getEnv "DISPLAY")!=""
-  then [
+    # Q: how to use isGui here?
+    # A: Not possible.
+    #    As isGui is evaluated after `imports` being evaluated,
+    #    use config.isGui here cause infinite loop.
+  ] ++ lib.optionals ((builtins.getEnv "DISPLAY")!="") [
     ./usr/gui.nix
-  ] else []);
+  ];
 
   home.stateVersion = "18.09";
   programs.home-manager.enable = true;