--- a/lisp/cmdloop.el	Mon Aug 13 11:33:40 2007 +0200
+++ b/lisp/cmdloop.el	Mon Aug 13 11:35:02 2007 +0200
@@ -130,9 +130,10 @@
   :group 'editing-basics)
 
 (defun command-error (error-object)
-  (let ((inhibit-quit t)
-	(debug-on-error nil)
-	(etype (car-safe error-object)))
+  (let* ((old-debug-on-error debug-on-error)
+	 (inhibit-quit t)
+	 (debug-on-error nil)
+	 (etype (car-safe error-object)))
     (setq quit-flag nil)
     (setq standard-output t)
     (setq standard-input t)
@@ -161,7 +162,12 @@
 
     (if (noninteractive)
         (progn
-          (message "%s exiting." emacs-program-name)
+	  (if old-debug-on-error
+	      (progn
+		(message "Backtrace:\n\n")
+		(backtrace)
+		(message "\n")))
+          (message "%s exiting\n." emacs-program-name)
           (kill-emacs -1)))
     t))
 
@@ -456,9 +462,28 @@
                (sleep-for 2))))
       ans)))
 
-;; these may be redefined later, but make the original def easily encapsulable
-(define-function 'yes-or-no-p 'yes-or-no-p-minibuf)
-(define-function 'y-or-n-p 'y-or-n-p-minibuf)
+(defun yes-or-no-p (prompt)
+  "Ask user a yes-or-no question.  Return t if answer is yes.
+The question is asked with a dialog box or the minibuffer, as appropriate.
+Takes one argument, which is the string to display to ask the question.
+It should end in a space; `yes-or-no-p' adds `(yes or no) ' to it.
+The user must confirm the answer with RET,
+and can edit it until it as been confirmed."
+  (if (should-use-dialog-box-p)
+      (yes-or-no-p-dialog-box prompt)
+    (yes-or-no-p-minibuf prompt)))
+
+(defun y-or-n-p (prompt)
+  "Ask user a \"y or n\" question.  Return t if answer is \"y\".
+Takes one argument, which is the string to display to ask the question.
+The question is asked with a dialog box or the minibuffer, as appropriate.
+It should end in a space; `y-or-n-p' adds `(y or n) ' to it.
+No confirmation of the answer is requested; a single character is enough.
+Also accepts Space to mean yes, or Delete to mean no."
+  (if (should-use-dialog-box-p)
+      (yes-or-no-p-dialog-box prompt)
+    (y-or-n-p-minibuf prompt)))
+
 
 
 (defun read-char ()