services: xorg: Define the <session-type> record type.

* gnu/services/xorg.scm (<session-type>): New record type.
  (%windowmaker-session-type, %ratpoison-session-type): New variables.
  (%default-xsessions): Use them.
  (xsessions-directory): Expect SESSIONS to be a list of <session-type>
  and rewrite accordingly.
  (slim-service): Adjust docstring.
* doc/guix.texi (X Window): Update accordingly.

1 files changed, 17 insertions, 1 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 0d2a61347f..7eed637c26 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -4531,7 +4531,8 @@ started by the @dfn{login manager}, currently SLiM.
 @deffn {Monadic Procedure} slim-service [#:allow-empty-passwords? #f] @
   [#:auto-login? #f] [#:default-user ""] [#:startx] @
   [#:theme @var{%default-slim-theme}] @
-  [#:theme-name @var{%default-slim-theme-name}]
+  [#:theme-name @var{%default-slim-theme-name}] @
+  [#:sessions @var{%default-sessions}]
 Return a service that spawns the SLiM graphical login manager, which in
 turn starts the X display server with @var{startx}, a command as returned by
 @code{xorg-start-command}.
@@ -4544,8 +4545,23 @@ If @var{theme} is @code{#f}, the use the default log-in theme; otherwise
 @var{theme} must be a gexp denoting the name of a directory containing the
 theme to use.  In that case, @var{theme-name} specifies the name of the
 theme.
+
+Last, @var{session} is a list of @code{<session-type>} objects denoting the
+available session types that can be chosen from the log-in screen.
 @end deffn
 
+@defvr {Scheme Variable} %default-sessions
+The list of default session types used by SLiM.
+@end defvr
+
+@defvr {Scheme Variable} %ratpoison-session-type
+Session type using the Ratpoison window manager.
+@end defvr
+
+@defvr {Scheme Variable} %windowmaker-session-type
+Session type using the WindowMaker window manager.
+@end defvr
+
 @defvr {Scheme Variable} %default-theme
 @defvrx {Scheme Variable} %default-theme-name
 The G-Expression denoting the default SLiM theme and its name.