* editfns.c (Fdelete_and_extract_region): New function.

(syms_of_editfns): register it.
* insdel.c (del_range): update del_range_1 call.
(del_range_1, del_range_2): Add a ret_string argument to
request that the deleted text be returned.
(del_range_byte, del_range_both): Update del_range_2 call.
* lisp.h (del_range_1, del_range_2): change prototype
* casefiddle.c (casify_region): Update del_range_1 call.
* coding.c (code_convert_region): Update del_range_2 call.
* fileio.c (Finsert_file_contents): Update del_range_2 call.

src/ChangeLog

@@ -1,3 +1,16 @@
+1999-12-06  Stefan Monnier  <monnier@cs.yale.edu>
+
+	* editfns.c (Fdelete_and_extract_region): New function.
+	(syms_of_editfns): register it.
+	* insdel.c (del_range): update del_range_1 call.
+	(del_range_1, del_range_2): Add a ret_string argument to
+	request that the deleted text be returned.
+	(del_range_byte, del_range_both): Update del_range_2 call.
+	* lisp.h (del_range_1, del_range_2): change prototype
+	* casefiddle.c (casify_region): Update del_range_1 call.
+	* coding.c (code_convert_region): Update del_range_2 call.
+	* fileio.c (Finsert_file_contents): Update del_range_2 call.
+
 1999-12-06  Gerd Moellmann  <gerd@gnu.org>
 
 	* xfaces.c (set_lface_from_font_name): Fix incomplete merge.

src/casefiddle.c

@@ -265,7 +265,7 @@ casify_region (flag, b, e)
 		  error ("Can't casify letters that change length");
 #if 0 /* This is approximately what we'd like to be able to do here */
 		  if (tolen < fromlen)
-		    del_range_1 (i + tolen, i + fromlen, 0);
+		    del_range_1 (i + tolen, i + fromlen, 0, 0);
 		  else if (tolen > fromlen)
 		    {
 		      TEMP_SET_PT (i + fromlen);

src/coding.c

@@ -4387,7 +4387,7 @@ code_convert_region (from, from_byte, to, to_byte, coding, encodep, replace)
 	  len = ZV - BEGV;
 	  new = Fcurrent_buffer ();
 	  set_buffer_internal_1 (prev);
-	  del_range_2 (from, from_byte, to, to_byte);
+	  del_range_2 (from, from_byte, to, to_byte, 0);
 	  TEMP_SET_PT_BOTH (from, from_byte);
 	  insert_from_buffer (XBUFFER (new), 1, len, 0);
 	  Fkill_buffer (new);

src/editfns.c

@@ -2509,6 +2509,16 @@ positions (integers or markers) specifying the stretch to be deleted.")
   del_range (XINT (start), XINT (end));
   return Qnil;
 }
+
+DEFUN ("delete-and-extract-region", Fdelete_and_extract_region,
+       Sdelete_and_extract_region, 2, 2, 0,
+  "Delete the text between START and END and return it.")
+  (start, end)
+     Lisp_Object start, end;
+{
+  validate_region (&start, &end);
+  return del_range_1 (XINT (start), XINT (end), 1, 1);
+}
 
 DEFUN ("widen", Fwiden, Swiden, 0, 0, "",
   "Remove restrictions (narrowing) from current buffer.\n\
@@ -3767,6 +3777,7 @@ functions if all the text being accessed has this property.");
   defsubr (&Ssubst_char_in_region);
   defsubr (&Stranslate_region);
   defsubr (&Sdelete_region);
+  defsubr (&Sdelete_and_extract_region);
   defsubr (&Swiden);
   defsubr (&Snarrow_to_region);
   defsubr (&Ssave_restriction);

src/fileio.c

@@ -3688,7 +3688,7 @@ actually used.")
 	  emacs_close (fd);
 	  specpdl_ptr--;
 	  /* Truncate the buffer to the size of the file.  */
-	  del_range_1 (same_at_start, same_at_end, 0);
+	  del_range_1 (same_at_start, same_at_end, 0, 0);
 	  goto handled;
 	}
       immediate_quit = 1;

src/insdel.c

@@ -2053,16 +2053,19 @@ void
 del_range (from, to)
      register int from, to;
 {
-  del_range_1 (from, to, 1);
+  del_range_1 (from, to, 1, 0);
 }
 
-/* Like del_range; PREPARE says whether to call prepare_to_modify_buffer.  */
+/* Like del_range; PREPARE says whether to call prepare_to_modify_buffer.
+   RET_STRING says to return the deleted text. */
 
-void
+Lisp_Object
-del_range_1 (from, to, prepare)
+del_range_1 (from, to, prepare, ret_string)
-     int from, to, prepare;
+     int from, to, prepare, ret_string;
 {
   int from_byte, to_byte;
+  Lisp_Object deletion;
+  struct gcpro gcpro1;
 
   /* Make args be valid */
   if (from < BEGV)
@@ -2071,7 +2074,7 @@ del_range_1 (from, to, prepare)
     to = ZV;
 
   if (to <= from)
-    return;
+    return Qnil;
 
   if (prepare)
     {
@@ -2083,8 +2086,11 @@ del_range_1 (from, to, prepare)
   from_byte = CHAR_TO_BYTE (from);
   to_byte = CHAR_TO_BYTE (to);
 
-  del_range_2 (from, from_byte, to, to_byte);
+  deletion = del_range_2 (from, from_byte, to, to_byte, ret_string);
+  GCPRO1(deletion);
   signal_after_change (from, to - from, 0);
+  UNGCPRO;
+  return deletion;
 }
 
 /* Like del_range_1 but args are byte positions, not char positions.  */
@@ -2120,7 +2126,7 @@ del_range_byte (from_byte, to_byte, prepare)
 	to_byte = CHAR_TO_BYTE (to);
     }
 
-  del_range_2 (from, from_byte, to, to_byte);
+  del_range_2 (from, from_byte, to, to_byte, 0);
   signal_after_change (from, to - from, 0);
 }
 
@@ -2158,17 +2164,18 @@ del_range_both (from, from_byte, to, to_byte, prepare)
 	to_byte = CHAR_TO_BYTE (to);
     }
 
-  del_range_2 (from, from_byte, to, to_byte);
+  del_range_2 (from, from_byte, to, to_byte, 0);
   signal_after_change (from, to - from, 0);
 }
 
 /* Delete a range of text, specified both as character positions
    and byte positions.  FROM and TO are character positions,
-   while FROM_BYTE and TO_BYTE are byte positions.  */
+   while FROM_BYTE and TO_BYTE are byte positions.
+   If RET_STRING is true, the deleted area is returned as a string. */
 
-void
+Lisp_Object
-del_range_2 (from, from_byte, to, to_byte)
+del_range_2 (from, from_byte, to, to_byte, ret_string)
-     int from, from_byte, to, to_byte;
+     int from, from_byte, to, to_byte, ret_string;
 {
   register int nbytes_del, nchars_del;
   int combined_after_bytes;
@@ -2199,12 +2206,15 @@ del_range_2 (from, from_byte, to, to_byte)
   else
     from_byte_1 = from_byte;
 
-  if (! EQ (current_buffer->undo_list, Qt))
+  if (ret_string || ! EQ (current_buffer->undo_list, Qt))
     deletion
       = make_buffer_string_both (from - !!combined_after_bytes,
 				 from_byte_1,
 				 to + combined_after_bytes,
 				 to_byte + combined_after_bytes, 1);
+  else
+    deletion = Qnil;
+
   if (combined_after_bytes)
     /* COMBINED_AFTER_BYTES nonzero means that the above code moved
        the gap.  We must move the gap again to a proper place.  */
@@ -2286,6 +2296,8 @@ del_range_2 (from, from_byte, to, to_byte)
   CHECK_MARKERS ();
 
   evaporate_overlays (from);
+
+  return deletion;
 }
 
 /* Call this if you're about to change the region of BUFFER from

src/lisp.h

@@ -2010,10 +2010,10 @@ extern void insert_before_markers P_ ((unsigned char *, int));
 extern void insert_before_markers_and_inherit P_ ((unsigned char *, int));
 extern void insert_from_string_before_markers P_ ((Lisp_Object, int, int, int, int, int));
 extern void del_range P_ ((int, int));
-extern void del_range_1 P_ ((int, int, int));
+extern Lisp_Object del_range_1 P_ ((int, int, int, int));
 extern void del_range_byte P_ ((int, int, int));
 extern void del_range_both P_ ((int, int, int, int, int));
-extern void del_range_2 P_ ((int, int, int, int));
+extern Lisp_Object del_range_2 P_ ((int, int, int, int, int));
 extern void modify_region P_ ((struct buffer *, int, int));
 extern void prepare_to_modify_buffer P_ ((int, int, int *));
 extern void signal_before_change P_ ((int, int, int *));