* eval.c (specbind): Disallow let-binding frame-local vars.

Remove left-over duplicate test.  Add comment.

diff --git a/etc/NEWS b/etc/NEWS
index b2a213c8fa2faa808b4267fcc36e8c3b50409b38..a60962cf1f444a09e0a0ccc9727873f655828800 100644 (file)
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -221,6 +221,7 @@ Secret Service API requires D-Bus for communication.
 \f
 * Lisp changes in Emacs 24.1
 
+** frame-local variables cannot be let-bound any more.
 ** prog-mode is a new major-mode meant to be the parent of programming mode.
 ** define-minor-mode accepts a new keyword :variable.
 

diff --git a/src/ChangeLog b/src/ChangeLog
index 14311049a17c3aaec9e67b963c74b3e63b0acbba..f258174625a052d1e9835434ed321d87f60c52e7 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2010-05-14  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+       * eval.c (specbind): Remove left-over duplicate test.
+       Disallow let-binding frame-local vars.  Add comment.
+
 2010-05-14  Eli Zaretskii  <eliz@gnu.org>
 
        Make the cache of bidi iterator states dynamically allocated.
@@ -5,7 +10,7 @@
        (bidi_init_it): Call it.
        (bidi_cache_iterator_state): Enlarge the cache if needed.
 
-       * bidi.c (bidi_move_to_visually_next): Renamed from
+       * bidi.c (bidi_move_to_visually_next): Rename from
        bidi_get_next_char_visually.  All callers changed.
 
 2010-05-14  Kenichi Handa  <handa@m17n.org>
@@ -18,8 +23,8 @@
        Set CMP_IT->reversed_p.
        (composition_update_it): Pay attention to CMP_IT->reversed_p.
 
-       * xdisp.c (set_iterator_to_next): Call
-       composition_compute_stop_pos with negative ENDPOS if we are
+       * xdisp.c (set_iterator_to_next):
+       Call composition_compute_stop_pos with negative ENDPOS if we are
        scanning backward.  Call composition_compute_stop_pos if scan
        direction is changed.
        (next_element_from_buffer): Call composition_compute_stop_pos with

diff --git a/src/eval.c b/src/eval.c
index 2a0330acc389e7c58dd842cc4c91ebc0458c111e..199c4705736d946fa3a387d3c25a80764189cef0 100644 (file)
--- a/src/eval.c
+++ b/src/eval.c
@@ -3308,6 +3308,21 @@ grow_specpdl ()
   specpdl_ptr = specpdl + count;
 }
 
+/* specpdl_ptr->symbol is a field which describes which variable is
+   let-bound, so it can be properly undone when we unbind_to.
+   It can have the following two shapes:
+   - SYMBOL : if it's a plain symbol, it means that we have let-bound
+     a symbol that is not buffer-local (at least at the time
+     the let binding started).  Note also that it should not be
+     aliased (i.e. when let-binding V1 that's aliased to V2, we want
+     to record V2 here).
+   - (SYMBOL WHERE . BUFFER) : this means that it is a let-binding for
+     variable SYMBOL which can be buffer-local.  WHERE tells us
+     which buffer is affected (or nil if the let-binding affects the
+     global value of the variable) and BUFFER tells us which buffer was
+     current (i.e. if WHERE is non-nil, then BUFFER==WHERE, otherwise
+     BUFFER did not yet have a buffer-local value).  */
+
 void
 specbind (symbol, value)
      Lisp_Object symbol, value;
@@ -3339,7 +3354,10 @@ specbind (symbol, value)
            set_internal (symbol, value, Qnil, 1);
          break;
        }
-    case SYMBOL_LOCALIZED: case SYMBOL_FORWARDED:
+    case SYMBOL_LOCALIZED:
+      if (SYMBOL_BLV (sym)->frame_local)
+       error ("Frame-local vars cannot be let-bound");
+    case SYMBOL_FORWARDED:
       {
        Lisp_Object ovalue = find_symbol_value (symbol);
        specpdl_ptr->func = 0;
@@ -3376,6 +3394,7 @@ specbind (symbol, value)
            /* FIXME: The third value `current_buffer' is only used in
               let_shadows_buffer_binding_p which is itself only used
               in set_internal for local_if_set.  */
+           eassert (NILP (where) || EQ (where, cur_buf));
            specpdl_ptr->symbol = Fcons (symbol, Fcons (where, cur_buf));
 
            /* If SYMBOL is a per-buffer variable which doesn't have a
@@ -3460,13 +3479,10 @@ unbind_to (count, value)
            Fset_default (symbol, this_binding.old_value);
          /* If `where' is non-nil, reset the value in the appropriate
             local binding, but only if that binding still exists.  */
-         else if (BUFFERP (where))
-           {
-             if (BUFFERP (where)
-                 ? !NILP (Flocal_variable_p (symbol, where))
-                 : !NILP (Fassq (symbol, XFRAME (where)->param_alist)))
-               set_internal (symbol, this_binding.old_value, where, 1);
-           }
+         else if (BUFFERP (where)
+                  ? !NILP (Flocal_variable_p (symbol, where))
+                  : !NILP (Fassq (symbol, XFRAME (where)->param_alist)))
+           set_internal (symbol, this_binding.old_value, where, 1);
        }
       /* If variable has a trivial value (no forwarding), we can
         just set it.  No need to check for constant symbols here,