services: xorg: Add 'set-xorg-configuration'.

* gnu/services/xorg.scm (gdm-service-type)[compose, extend]: New fields.
(set-xorg-configuration): New procedure.
* doc/guix.texi (Keyboard Layout): Use it.
(X Window): Document it.
* gnu/system/examples/desktop.tmpl: Add 'keyboard-layout' fields.

2 files changed, 32 insertions, 4 deletions

diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index 7745f9a3cc..26ca0d4f1f 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -99,7 +99,8 @@
 
             gdm-configuration
             gdm-service-type
-            gdm-service))
+            gdm-service
+            set-xorg-configuration))
 
 ;;; Commentary:
 ;;;
@@ -875,6 +876,15 @@ the GNOME desktop environment.")
                                            xorg-configuration-keyboard-layout
                                            gdm-configuration-xorg))))
 
+                ;; For convenience, this service can be extended with an
+                ;; <xorg-configuration> record.  Take the first one that
+                ;; comes.
+                (compose first)
+                (extend (lambda (config xorg-configuration)
+                          (gdm-configuration
+                           (inherit config)
+                           (xorg-configuration xorg-configuration))))
+
                 (default-value (gdm-configuration))
                 (description
                  "Run the GNOME Desktop Manager (GDM), a program that allows
@@ -908,4 +918,14 @@ password."
             (gdm gdm)
             (allow-empty-passwords? allow-empty-passwords?))))
 
+(define* (set-xorg-configuration config
+                                 #:optional
+                                 (login-manager-service-type
+                                  gdm-service-type))
+  "Tell the log-in manager (of type @var{login-manager-service-type}) to use
+@var{config}, an <xorg-configuration> record."
+  (simple-service 'set-xorg-configuration
+                  login-manager-service-type
+                  config))
+
 ;;; xorg.scm ends here
diff --git a/gnu/system/examples/desktop.tmpl b/gnu/system/examples/desktop.tmpl
index ff4c12b24a..baeb5e2d77 100644
--- a/gnu/system/examples/desktop.tmpl
+++ b/gnu/system/examples/desktop.tmpl
@@ -3,7 +3,7 @@
 ;; root partition is encrypted with LUKS.
 
 (use-modules (gnu) (gnu system nss))
-(use-service-modules desktop)
+(use-service-modules desktop xorg)
 (use-package-modules certs gnome)
 
 (operating-system
@@ -11,11 +11,16 @@
   (timezone "Europe/Paris")
   (locale "en_US.utf8")
 
+  ;; Choose US English keyboard layout.  The "altgr-intl"
+  ;; variant provides dead keys for accented characters.
+  (keyboard-layout (keyboard-layout "us" "altgr-intl"))
+
   ;; Use the UEFI variant of GRUB with the EFI System
   ;; Partition mounted on /boot/efi.
   (bootloader (bootloader-configuration
                 (bootloader grub-efi-bootloader)
-                (target "/boot/efi")))
+                (target "/boot/efi")
+                (keyboard-layout keyboard-layout)))
 
   ;; Specify a mapped device for the encrypted root partition.
   ;; The UUID is that returned by 'cryptsetup luksUUID'.
@@ -58,7 +63,10 @@
   ;; include the X11 log-in service, networking with
   ;; NetworkManager, and more.
   (services (append (list (service gnome-desktop-service-type)
-                          (service xfce-desktop-service-type))
+                          (service xfce-desktop-service-type)
+                          (set-xorg-configuration
+                           (xorg-configuration
+                            (keyboard-layout keyboard-layout))))
                     %desktop-services))
 
   ;; Allow resolution of '.local' host names with mDNS.