exwm service: init

nixos/modules/services/x11/window-managers/default.nix

@@ -13,6 +13,7 @@ in
     ./clfswm.nix
     ./compiz.nix
     ./dwm.nix
+    ./exwm.nix
     ./fluxbox.nix
     ./herbstluftwm.nix
     ./i3.nix

nixos/modules/services/x11/window-managers/exwm.nix

@@ -0,0 +1,55 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.xserver.windowManager.exwm;
+  loadScript = pkgs.writeText "emacs-exwm-load" ''
+    (require 'exwm)
+    ${optionalString cfg.enableDefaultConfig ''
+      (require 'exwm-config)
+      (exwm-config-default)
+    ''}
+  '';
+  packages = epkgs: cfg.extraPackages epkgs ++ [ epkgs.exwm ];
+  exwm-emacs = pkgs.emacsWithPackages packages;
+in
+
+{
+  options = {
+    services.xserver.windowManager.exwm = {
+      enable = mkEnableOption "exwm";
+      enableDefaultConfig = mkOption {
+        default = true;
+        example = false;
+        type = lib.types.bool;
+        description = "Enable an uncustomised exwm configuration.";
+      };
+      extraPackages = mkOption {
+        default = self: [];
+        example = literalExample ''
+          epkgs: [
+            epkgs.emms
+            epkgs.magit
+            epkgs.proofgeneral
+          ]
+        '';
+        description = ''
+          Extra packages available to Emacs. The value must be a
+          function which receives the attrset defined in
+          <varname>emacsPackages</varname> as the sole argument.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.xserver.windowManager.session = singleton {
+      name = "exwm";
+      start = ''
+        ${exwm-emacs}/bin/emacs -l ${loadScript}
+      '';
+    };
+    environment.systemPackages = [ exwm-emacs ];
+  };
+}