(specbind): If SYMBOL has a frame-local binding, record

the frame on the binding stack.  Change format of entries for
local bindings on the binding stack to '(SYMBOL . WHERE)'.
(unbind_to): Handle unbinding a frame-local variable.

diff --git a/src/eval.c b/src/eval.c
index e000ea6..6ee3d89 100644 (file)
--- a/src/eval.c
+++ b/src/eval.c
@@ -2923,35 +2923,42 @@ specbind (symbol, value)
     }
   else
     {
+      Lisp_Object valcontents;
+      
       ovalue = find_symbol_value (symbol);
       specpdl_ptr->func = 0;
       specpdl_ptr->old_value = ovalue;
 
-      if (BUFFER_LOCAL_VALUEP (XSYMBOL (symbol)->value)
-         || SOME_BUFFER_LOCAL_VALUEP (XSYMBOL (symbol)->value)
-         || BUFFER_OBJFWDP (XSYMBOL (symbol)->value))
+      valcontents = XSYMBOL (symbol)->value;
+
+      if (BUFFER_LOCAL_VALUEP (valcontents)
+         || SOME_BUFFER_LOCAL_VALUEP (valcontents)
+         || BUFFER_OBJFWDP (valcontents))
        {
-         Lisp_Object current_buffer, binding_buffer;
+         Lisp_Object where;
          
          /* For a local variable, record both the symbol and which
-            buffer's value we are saving.  */
-         current_buffer = Fcurrent_buffer ();
-         binding_buffer = current_buffer;
-         
-         /* If the variable is not local in this buffer,
-            we are saving the global value, so restore that.  */
-         if (NILP (Flocal_variable_p (symbol, binding_buffer)))
-           binding_buffer = Qnil;
-         specpdl_ptr->symbol
-           = Fcons (symbol, Fcons (binding_buffer, current_buffer));
+            buffer's or frame's value we are saving.  */
+         if (!NILP (Flocal_variable_p (symbol, Qnil)))
+           where = Fcurrent_buffer ();
+         else if (!BUFFER_OBJFWDP (valcontents)
+                  && XBUFFER_LOCAL_VALUE (valcontents)->found_for_frame)
+           where = XBUFFER_LOCAL_VALUE (valcontents)->frame;
+         else
+           where = Qnil;
+
+         /* We're not using the `unused' slot in the specbinding
+            structure because this would mean we have to do more
+            work for simple variables.  */
+         specpdl_ptr->symbol = Fcons (symbol, where);
 
          /* If SYMBOL is a per-buffer variable which doesn't have a
             buffer-local value here, make the `let' change the global
             value by changing the value of SYMBOL in all buffers not
             having their own value.  This is consistent with what
             happens with other buffer-local variables.  */
-         if (NILP (binding_buffer)
-             && BUFFER_OBJFWDP (XSYMBOL (symbol)->value))
+         if (NILP (where)
+             && BUFFER_OBJFWDP (valcontents))
            {
              ++specpdl_ptr;
              Fset_default (symbol, value);
@@ -2996,30 +3003,31 @@ unbind_to (count, value)
   while (specpdl_ptr != specpdl + count)
     {
       --specpdl_ptr;
-      
+
       if (specpdl_ptr->func != 0)
        (*specpdl_ptr->func) (specpdl_ptr->old_value);
       /* Note that a "binding" of nil is really an unwind protect,
         so in that case the "old value" is a list of forms to evaluate.  */
       else if (NILP (specpdl_ptr->symbol))
        Fprogn (specpdl_ptr->old_value);
-      /* If the symbol is a list, it is really (SYMBOL BINDING_BUFFER
-        . CURRENT_BUFFER) and it indicates we bound a variable that
-        has buffer-local bindings.  BINDING_BUFFER nil means that the
-        variable had the default value when it was bound.  */
+      /* If the symbol is a list, it is really (SYMBOL . WHERE) where
+        WHERE is either nil, a buffer, or a frame.  If WHERE is a
+        buffer or frame, this indicates we bound a variable that had
+        a buffer-local or frmae-local binding..  WHERE nil means that
+        the variable had the default value when it was bound.  */
       else if (CONSP (specpdl_ptr->symbol))
        {
-         Lisp_Object symbol, buffer;
+         Lisp_Object symbol, where;
 
          symbol = XCAR (specpdl_ptr->symbol);
-         buffer = XCAR (XCDR (specpdl_ptr->symbol));
+         where = XCDR (specpdl_ptr->symbol);
 
-         /* Handle restoring a default value.  */
-         if (NILP (buffer))
+         if (NILP (where))
            Fset_default (symbol, specpdl_ptr->old_value);
-         /* Handle restoring a value saved from a live buffer.  */
-         else
-           set_internal (symbol, specpdl_ptr->old_value, XBUFFER (buffer), 1);
+         else if (BUFFERP (where))
+           set_internal (symbol, specpdl_ptr->old_value, XBUFFER (where), 1);
+         else 
+           set_internal (symbol, specpdl_ptr->old_value, NULL, 1);
        }
       else
        {