Avoid (most) uses of XCAR/XCDR as lvalues, for flexibility in experimenting

with lisp system changes.

1 files changed, 37 insertions, 25 deletions

diff --git a/src/keyboard.c b/src/keyboard.c
index 414f72b971f..23b1f0d5b57 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -2358,15 +2358,21 @@ read_char (commandflag, nmaps, maps, prev_event, used_mouse_menu)
         KBOARD *kb = FRAME_KBOARD (XFRAME (selected_frame));
         if (kb != current_kboard)
           {
-            Lisp_Object *tailp = &kb->kbd_queue;
+            Lisp_Object link = kb->kbd_queue;
             /* We shouldn't get here if we were in single-kboard mode!  */
             if (single_kboard)
               abort ();
-            while (CONSP (*tailp))
-              tailp = &XCDR (*tailp);
-            if (!NILP (*tailp))
-              abort ();
-            *tailp = Fcons (c, Qnil);
+            if (CONSP (link))
+              {
+                while (CONSP (XCDR (link)))
+                  link = XCDR (link);
+                if (!NILP (XCDR (link)))
+                  abort ();
+              }
+            if (!CONSP (link))
+              kb->kbd_queue = Fcons (c, Qnil);
+            else
+              XSETCDR (link, Fcons (c, Qnil));
             kb->kbd_queue_has_data = 1;
             current_kboard = kb;
             /* This is going to exit from read_char
@@ -2581,12 +2587,18 @@ read_char (commandflag, nmaps, maps, prev_event, used_mouse_menu)
 #ifdef MULTI_KBOARD
       if (! NILP (c) && (kb != current_kboard))
         {
-          Lisp_Object *tailp = &kb->kbd_queue;
-          while (CONSP (*tailp))
-            tailp = &XCDR (*tailp);
-          if (!NILP (*tailp))
-            abort ();
-          *tailp = Fcons (c, Qnil);
+          Lisp_Object link = kb->kbd_queue;
+          if (CONSP (link))
+            {
+              while (CONSP (XCDR (link)))
+                link = XCDR (link);
+              if (!NILP (XCDR (link)))
+                abort ();
+            }
+          if (!CONSP (link))
+            kb->kbd_queue = Fcons (c, Qnil);
+          else
+            XSETCDR (link, Fcons (c, Qnil));
           kb->kbd_queue_has_data = 1;
           c = Qnil;
           if (single_kboard)
@@ -2702,7 +2714,7 @@ read_char (commandflag, nmaps, maps, prev_event, used_mouse_menu)
       if (EQ (posn, Qmenu_bar) || EQ (posn, Qtool_bar))
         {
           /* Change menu-bar to (menu-bar) as the event "position".  */
-          POSN_BUFFER_POSN (EVENT_START (c)) = Fcons (posn, Qnil);
+          POSN_BUFFER_SET_POSN (EVENT_START (c), Fcons (posn, Qnil));
 
           also_record = c;
           Vunread_command_events = Fcons (c, Vunread_command_events);
@@ -6854,19 +6866,19 @@ parse_menu_item (item, notreal, inmenubar)
     {
       /* We have to create a cachelist.  */
       CHECK_IMPURE (start);
-      XCDR (start) = Fcons (Fcons (Qnil, Qnil), XCDR (start));
+      XSETCDR (start, Fcons (Fcons (Qnil, Qnil), XCDR (start)));
       cachelist = XCAR (XCDR (start));
       newcache = 1;
       tem = AREF (item_properties, ITEM_PROPERTY_KEYEQ);
       if (!NILP (keyhint))
         {
-          XCAR (cachelist) = XCAR (keyhint);
+          XSETCAR (cachelist, XCAR (keyhint));
           newcache = 0;
         }
       else if (STRINGP (tem))
         {
-          XCDR (cachelist) = Fsubstitute_command_keys (tem);
-          XCAR (cachelist) = Qt;
+          XSETCDR (cachelist, Fsubstitute_command_keys (tem));
+          XSETCAR (cachelist, Qt);
         }
     }
   
@@ -6924,10 +6936,10 @@ parse_menu_item (item, notreal, inmenubar)
               && ! NILP (Fget (def, Qmenu_alias)))
             def = XSYMBOL (def)->function;
           tem = Fwhere_is_internal (def, Qnil, Qt, Qnil);
-          XCAR (cachelist) = tem;
+          XSETCAR (cachelist, tem);
           if (NILP (tem))
             {
-              XCDR (cachelist) = Qnil;
+              XSETCDR (cachelist, Qnil);
               chkcache = 0;
             }
         }
@@ -6948,7 +6960,7 @@ parse_menu_item (item, notreal, inmenubar)
               if (STRINGP (XCDR (prefix)))
                 tem = concat2 (tem, XCDR (prefix));
             }
-          XCDR (cachelist) = tem;
+          XSETCDR (cachelist, tem);
         }
     }
 
@@ -6956,7 +6968,7 @@ parse_menu_item (item, notreal, inmenubar)
   if (newcache && !NILP (tem))
     {
       tem = concat3 (build_string ("  ("), tem, build_string (")"));
-      XCDR (cachelist) = tem;
+      XSETCDR (cachelist, tem);
     }
 
   /* If we only want to precompute equivalent key bindings, stop here. */
@@ -7474,7 +7486,7 @@ read_char_x_menu_prompt (nmaps, maps, prev_event, used_mouse_menu)
               record_menu_key (XCAR (tem));
               if (SYMBOLP (XCAR (tem))
                   || INTEGERP (XCAR (tem)))
-                XCAR (tem) = Fcons (XCAR (tem), Qdisabled);
+                XSETCAR (tem, Fcons (XCAR (tem), Qdisabled));
             }
 
           /* If we got more than one event, put all but the first
@@ -8466,8 +8478,8 @@ read_key_sequence (keybuf, bufsize, prompt, dont_downcase_last,
 
                   /* Zap the position in key, so we know that we've
                      expanded it, and don't try to do so again.  */
-                  POSN_BUFFER_POSN (EVENT_START (key))
-                    = Fcons (posn, Qnil);
+                  POSN_BUFFER_SET_POSN (EVENT_START (key),
+                                        Fcons (posn, Qnil));
 
                   mock_input = t + 2;
                   goto replay_sequence;
@@ -9203,7 +9215,7 @@ a special event, so ignore the prefix argument and don't clear it.")
             {
               tem = Fnthcdr (Vhistory_length, Vcommand_history);
               if (CONSP (tem))
-                XCDR (tem) = Qnil;
+                XSETCDR (tem, Qnil);
             }
         }