[STUMP] [PATCH] Add variable to confirm killing StumpWM

When quitting StumpWM using the command `quit', the variable
`*confirm-kill-stumpwm*' can hold a predicate which evaluates to t to
quit StumpWM.

The function `windows-query-on-exit' is a predicate that evaluates to
t if no window exist or the user answers "yes" to the query.

`*confirm-kill-stumpwm*' can hold any predicate but
`windows-query-on-exit' is provided so the user do not accidentally
quit StumpWM while windows exist.

`*confirm-kill-stumpwm*' is nil by default so there is no change on
the current behavior.
---
 user.lisp |   23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/user.lisp b/user.lisp
index 5f358de..04e4030 100644
--- a/user.lisp
+++ b/user.lisp
@@ -31,7 +31,10 @@
 	  run-or-raise
           run-or-pull
 	  run-shell-command
-          window-send-string))
+          window-send-string
+          *confirm-kill-stumpwm*
+          windows-query-on-exit
+          ))
 
 (defun restarts-menu (err)
   "Display a menu with the active restarts and let the user pick
@@ -222,10 +225,24 @@ such a case, kill the shell command to resume StumpWM."
 
 (defcommand-alias abort keyboard-quit)
 
+(defun windows-query-on-exit ()
+  "t if no window exist or the user wants to exit anyway."
+  (or (null (all-windows))
+      (yes-or-no-p "Active windows exist; kill them and exit anyway? ")))
+
+(defvar *confirm-kill-stumpwm* nil
+  "If non-nil, predicate function to confirm killing StumpWM.
+
+Nil means to not ask.")
 
 (defcommand quit () ()
-"Quit StumpWM."
-  (throw :top-level :quit))
+  "Quit StumpWM.
+
+Use the variable `*confirm-kill-stumpwm*' to hold a predicate.  This
+predicate evaluates to t when you want to quit."
+  (when (or (null *confirm-kill-stumpwm*)
+            (funcall *confirm-kill-stumpwm*))
+    (throw :top-level :quit)))
 
 (defcommand restart-soft () ()
   "Soft Restart StumpWM. The lisp process isn't restarted. Instead,
-- 
1.7.10.4