(Qundefined): New variable.

(syms_of_keyboard): Set up Qundefined.
(menu_bar_items): Don't reverse the items.
Process the maps in reverse order.
(menu_bar_item): If definition is `undefined',
delete any menu bar item already made, and don't make one.

1 files changed, 22 insertions, 4 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 316811d49ba..06e47dabf99 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -242,6 +242,7 @@ unsigned long last_event_timestamp;
 Lisp_Object Qself_insert_command;
 Lisp_Object Qforward_char;
 Lisp_Object Qbackward_char;
+Lisp_Object Qundefined;
 
 /* read_key_sequence stores here the command definition of the
    key sequence that it reads.  */
@@ -3186,7 +3187,7 @@ menu_bar_items ()
 
   result = Qnil;
 
-  for (mapno = 0; mapno < nmaps; mapno++)
+  for (mapno = nmaps - 1; mapno >= 0; mapno--)
     {
       if (! NILP (maps[mapno]))
         def = get_keyelt (access_keymap (maps[mapno], Qmenu_bar, 1, 0));
@@ -3227,6 +3228,9 @@ menu_bar_one_keymap (keymap, result)
                 result = menu_bar_item (key, item_string,
                                         Fcdr (binding), result);
             }
+          else if (EQ (binding, Qundefined))
+            result = menu_bar_item (key, item_string,
+                                    Fcdr (binding), result);
         }
       else if (XTYPE (item) == Lisp_Vector)
         {
@@ -3245,6 +3249,9 @@ menu_bar_one_keymap (keymap, result)
                     result = menu_bar_item (key, item_string,
                                             Fcdr (binding), result);
                 }
+              else if (EQ (binding, Qundefined))
+                result = menu_bar_item (key, item_string,
+                                        Fcdr (binding), result);
             }
         }
     }
@@ -3256,9 +3263,17 @@ static Lisp_Object
 menu_bar_item (key, item_string, def, result)
      Lisp_Object key, item_string, def, result;
 {
-  Lisp_Object tem, elt;
+  Lisp_Object tem;
   Lisp_Object enabled;
 
+  if (EQ (def, Qundefined))
+    {
+      /* If a map has an explicit nil as definition,
+         discard any previously made menu bar item.  */
+      tem = Fassq (key, result);
+      return Fdelq (tem, result);
+    }
+
   /* See if this entry is enabled.  */
   enabled = Qt;
 
@@ -3273,8 +3288,8 @@ menu_bar_item (key, item_string, def, result)
 
   /* Add an entry for this key and string
      if there is none yet.  */
-  elt = Fassq (key, result);
-  if (!NILP (enabled) && NILP (elt))
+  tem = Fassq (key, result);
+  if (!NILP (enabled) && NILP (tem))
     result = Fcons (Fcons (key, Fcons (item_string, Qnil)), result);
 
   return result;
@@ -4910,6 +4925,9 @@ syms_of_keyboard ()
   Qdisabled = intern ("disabled");
   staticpro (&Qdisabled);
 
+  Qundefined = intern ("undefined");
+  staticpro (&Qundefined);
+
   Qpre_command_hook = intern ("pre-command-hook");
   staticpro (&Qpre_command_hook);