bug#5937: 23.1.95; why saving empty abbrev tables

[Leo]

On 2011-03-28 04:35 +0800, Stefan Monnier wrote:
> I don't think we need such a thing.  We just need to make it clear what
> those empty tables mean and keep them out of the way.  I.e. move them to
> the end of the buffer and add a comment before them explaining that
> these are currently empty.

OK let's do this. I didn't insert a line explaining empty tables because
they are obvious (See this screenshot: http://imgur.com/zCegB.png).

(BTW, after looking at that screenshot I realised Makefile mode
introduces 6 abbrev tables; amazing.)

Let me know if you are OK with this patch.

Thanks,
Leo

=== modified file 'lisp/abbrev.el'
--- lisp/abbrev.el      2011-03-22 15:38:40 +0000
+++ lisp/abbrev.el      2011-03-28 03:52:49 +0000
@@ -123,8 +123,13 @@
       (if local
           (insert-abbrev-table-description
            (abbrev-table-name local-table) t)
-        (dolist (table abbrev-table-name-list)
-          (insert-abbrev-table-description table t)))
+        (let (empty-tables)
+         (dolist (table abbrev-table-name-list)
+           (if (abbrev-table-empty-p (symbol-value table))
+               (push table empty-tables)
+             (insert-abbrev-table-description table t)))
+         (dolist (table (nreverse empty-tables))
+           (insert-abbrev-table-description table t))))
       (goto-char (point-min))
       (set-buffer-modified-p nil)
       (edit-abbrevs-mode)
@@ -420,6 +425,18 @@
   (and (vectorp object)
        (numberp (abbrev-table-get object :abbrev-table-modiff))))
 
+(defun abbrev-table-empty-p (object &optional ignore-system)
+  "Return nil if there are no abbrev symbols in OBJECT.
+If IGNORE-SYSTEM is non-nil, system definitions are ignored."
+  (unless (abbrev-table-p object)
+    (error "Non abbrev table object"))
+  (not (catch 'some
+        (mapatoms (lambda (abbrev)
+                    (unless (or (zerop (length (symbol-name abbrev)))
+                                (and ignore-system (abbrev-get abbrev 
:system)))
+                      (throw 'some t)))
+                  object))))
+
 (defvar global-abbrev-table (make-abbrev-table)
   "The abbrev table whose abbrevs affect all buffers.
 Each buffer may also have a local abbrev table.