installer: Add services page.

Add a page to select services, for now only desktop environments choice is
available.

* gnu/installer.scm (steps): Add services step.
* gnu/installer/newt.scm (newt-installer): Add services-page field.
* gnu/installer/newt/services.scm: New file.
* gnu/installer/record.scm (installer): Add services-page field.
* gnu/installer/services.scm: New file.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add new files.
* po/guix/POTFILES.in: Add new files.

1 files changed, 59 insertions, 0 deletions

diff --git a/gnu/installer/services.scm b/gnu/installer/services.scm
new file mode 100644
index 0000000000..ed44b87682
--- /dev/null
+++ b/gnu/installer/services.scm
@@ -0,0 +1,59 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2018 Mathieu Othacehe <m.othacehe@gmail.com>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu installer services)
+  #:use-module (guix records)
+  #:export (<desktop-environment>
+            desktop-environment
+            make-desktop-environment
+            desktop-environment-name
+            desktop-environment-snippet
+
+            %desktop-environments
+            desktop-environments->configuration))
+
+(define-record-type* <desktop-environment>
+  desktop-environment make-desktop-environment
+  desktop-environment?
+  (name            desktop-environment-name) ;string
+  (snippet         desktop-environment-snippet)) ;symbol
+
+;; This is the list of desktop environments supported as services.
+(define %desktop-environments
+  (list
+   (desktop-environment
+    (name "GNOME")
+    (snippet '(gnome-desktop-service)))
+   (desktop-environment
+    (name "Xfce")
+    (snippet '(xfce-desktop-service)))
+   (desktop-environment
+    (name "MATE")
+    (snippet '(mate-desktop-service)))
+   (desktop-environment
+    (name "Enlightenment")
+    (snippet '(service enlightenment-desktop-service-type)))))
+
+(define (desktop-environments->configuration desktop-environments)
+  "Return the configuration field for DESKTOP-ENVIRONMENTS."
+  (let ((snippets
+         (map desktop-environment-snippet desktop-environments)))
+    `(,@(if (null? snippets)
+            '()
+            `((services (cons* ,@snippets
+                               %desktop-services)))))))