* cmds.c (overwrite_binary_mode): Deleted; this implements the

	wrong feature.
	(Qoverwrite_mode_binary): New variable.
	(internal_self_insert): If current_buffer->overwrite_mode is
	`overwrite-mode-binary', do as overwrite_binary_mode used to.
	(syms_of_cmds): Remove defvar of overwrite_binary_mode; initialize
	Qoverwrite_mode_binary.
	* buffer.c (syms_of_buffer): Doc fix for overwrite_mode.
	* buffer.h (struct buffer): Doc fix.

3 files changed, 16 insertions, 10 deletions

diff --git a/src/buffer.c b/src/buffer.c
index e254db179c7..aec489eab56 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1610,6 +1610,10 @@ Automatically becomes buffer-local when set in any fashion.");
 
   DEFVAR_PER_BUFFER ("overwrite-mode", &current_buffer->overwrite_mode, Qnil,
     "Non-nil if self-insertion should replace existing text.\n\
+If non-nil and not `overwrite-mode-binary', self-insertion still\n\
+inserts at the end of a line, and inserts when point is before a tab,\n\
+unless that tab is displaying as only one space.\n\
+If `overwrite-mode-binary', self-insertion replaces newlines and tabs too.\n\
 Automatically becomes buffer-local when set in any fashion.");
 
   DEFVAR_PER_BUFFER ("buffer-display-table", &current_buffer->display_table,
diff --git a/src/buffer.h b/src/buffer.h
index 99f30d0315f..35a7d62685d 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -256,7 +256,8 @@ struct buffer
 #endif
     /* Alist of (FUNCTION . STRING) for each minor mode enabled in buffer. */
     Lisp_Object minor_modes;
-    /* t if "self-insertion" should overwrite */
+    /* t if "self-insertion" should overwrite; `binary' if it should also
+       overwrite newlines and tabs - for editing executables and the like.  */
     Lisp_Object overwrite_mode;
     /* non-nil means abbrev mode is on.  Expand abbrevs automatically. */
     Lisp_Object abbrev_mode;
diff --git a/src/cmds.c b/src/cmds.c
index 9dfd2b48a8f..e81d7c61e59 100644
--- a/src/cmds.c
+++ b/src/cmds.c
@@ -26,7 +26,9 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
 Lisp_Object Qkill_forward_chars, Qkill_backward_chars, Vblink_paren_function;
 
-int overwrite_binary_mode;
+/* A possible value for a buffer's overwrite-mode variable.  */
+Lisp_Object Qoverwrite_mode_binary;
+
 
 DEFUN ("forward-char", Fforward_char, Sforward_char, 0, 1, "p",
   "Move point right ARG characters (left if ARG negative).\n\
@@ -273,14 +275,16 @@ internal_self_insert (c1, noautofill)
   Lisp_Object tem;
   register enum syntaxcode synt;
   register int c = c1;
+  Lisp_Object overwrite = current_buffer->overwrite_mode;
 
   if (!NILP (Vbefore_change_function) || !NILP (Vafter_change_function))
     hairy = 1;
 
-  if (!NILP (current_buffer->overwrite_mode)
+  if (!NILP (overwrite)
       && point < ZV
-      && (overwrite_binary_mode || (c != '\n' && FETCH_CHAR (point) != '\n'))
-      && (overwrite_binary_mode
+      && (EQ (overwrite, Qoverwrite_mode_binary)
+          || (c != '\n' && FETCH_CHAR (point) != '\n'))
+      && (EQ (overwrite, Qoverwrite_mode_binary)
           || FETCH_CHAR (point) != '\t'
           || XINT (current_buffer->tab_width) <= 0
           || XFASTINT (current_buffer->tab_width) > 20
@@ -336,11 +340,8 @@ syms_of_cmds ()
   Qkill_forward_chars = intern ("kill-forward-chars");
   staticpro (&Qkill_forward_chars);
 
-  DEFVAR_BOOL ("overwrite-binary-mode", &overwrite_binary_mode,
-    "*Non-nil means overwrite mode treats tab and newline normally.\n\
-Ordinarily, overwriting preserves a tab until its whole width is overwritten\n\
-and never replaces a newline.");
-  overwrite_binary_mode = 1;
+  Qoverwrite_mode_binary = intern ("overwrite-mode-binary");
+  staticpro (&Qoverwrite_mode_binary);
 
   DEFVAR_LISP ("blink-paren-function", &Vblink_paren_function,
     "Function called, if non-nil, whenever a close parenthesis is inserted.\n\