fvwm3: nixos module

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

@@ -20,6 +20,7 @@ in
     ./exwm.nix
     ./fluxbox.nix
     ./fvwm2.nix
+    ./fvwm3.nix
     ./herbstluftwm.nix
     ./i3.nix
     ./jwm.nix

nixos/modules/services/x11/window-managers/fvwm3.nix

@@ -0,0 +1,35 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.xserver.windowManager.fvwm3;
+  inherit (pkgs) fvwm3;
+in
+
+{
+
+  ###### interface
+
+  options = {
+    services.xserver.windowManager.fvwm3 = {
+      enable = mkEnableOption "Fvwm3 window manager";
+    };
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+    services.xserver.windowManager.session = singleton
+      { name = "fvwm3";
+        start =
+          ''
+            ${fvwm3}/bin/fvwm3 &
+            waitPID=$!
+          '';
+      };
+
+    environment.systemPackages = [ fvwm3 ];
+  };
+}