(clear-abbrev-table): Always return nil (Bug#2515).

[gnu-emacs] / lisp / abbrev.el

diff --git a/lisp/abbrev.el b/lisp/abbrev.el
index 136dc2b9b9d3cc16508c8240642523794cc96b77..5b4ffe3ae8f63722edb1701013af8ab12ef5e6ba 100644 (file)
--- a/lisp/abbrev.el
+++ b/lisp/abbrev.el
@@ -1,7 +1,7 @@
 ;;; abbrev.el --- abbrev mode commands for Emacs
 
 ;; Copyright (C) 1985, 1986, 1987, 1992, 2001, 2002, 2003, 2004,
-;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+;;   2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: abbrev convenience
@@ -521,7 +521,8 @@ the current abbrev table before abbrev lookup happens."
       (set newsym nil)      ; Make sure it won't be confused for an abbrev.
       (setplist newsym (symbol-plist sym)))
     (abbrev-table-put table :abbrev-table-modiff
-                      (1+ (abbrev-table-get table :abbrev-table-modiff)))))
+                      (1+ (abbrev-table-get table :abbrev-table-modiff))))
+  nil)
 
 (defun define-abbrev (table name expansion &optional hook &rest props)
   "Define an abbrev in TABLE named NAME, to expand to EXPANSION and call HOOK.
@@ -530,8 +531,9 @@ EXPANSION should usually be a string.
 To undefine an abbrev, define it with EXPANSION = nil.
 If HOOK is non-nil, it should be a function of no arguments;
 it is called after EXPANSION is inserted.
-If EXPANSION is not a string, the abbrev is a special one,
- which does not expand in the usual way but only runs HOOK.
+If EXPANSION is not a string (and not nil), the abbrev is a
+ special one, which does not expand in the usual way but only
+ runs HOOK.
 
 PROPS is a property list.  The following properties are special:
 - `:count': the value for the abbrev's usage-count, which is incremented each
@@ -824,10 +826,11 @@ is not undone."
         ;; to do the expansion.
         (let ((val (symbol-value last-abbrev)))
           (unless (stringp val)
-            (error "value of abbrev-symbol must be a string"))
-          (delete-region (point) (+ (point) (length val)))
+            (error "Value of abbrev-symbol must be a string"))
           ;; Don't inherit properties here; just copy from old contents.
           (insert last-abbrev-text)
+          ;; Delete after inserting, to better preserve markers.
+          (delete-region (point) (+ (point) (length val)))
           (setq last-abbrev-text nil))))))
 
 (defun abbrev--write (sym)
@@ -904,8 +907,8 @@ Properties with special meaning:
   means that an abbrev can only be a single word.  The submatch 1 is treated
   as the potential name of an abbrev.
 - `:enable-function' can be set to a function of no argument which returns
-  non-nil iff the abbrevs in this table should be used for this instance
-  of `expand-abbrev'."
+  non-nil if and only if the abbrevs in this table should be used for this
+  instance of `expand-abbrev'."
   ;; We used to manually add the docstring, but we also want to record this
   ;; location as the definition of the variable (in load-history), so we may
   ;; as well just use `defvar'.