1 files changed, 71 insertions, 0 deletions

diff --git a/lisp/gnus/gnus-mule.el b/lisp/gnus/gnus-mule.el
new file mode 100644
index 00000000000..c83bdb27d96
--- /dev/null
+++ b/lisp/gnus/gnus-mule.el
@@ -0,0 +1,71 @@
+;;; gnus-mule.el --- Provide backward compatibility function to GNUS
+
+;; Copyright (C) 1995,1997 Free Software Foundation, Inc.
+;; Copyright (C) 1995, 2000 Electrotechnical Laboratory, JAPAN.
+
+;; Keywords: gnus, mule
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 2, or (at your option)
+;; any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;; This file provides the function `gnus-mule-add-group' for backward
+;; compatibility with old version of Gnus included in Emacs 20.
+
+(require 'gnus-sum)
+
+;;;###autoload
+(defun gnus-mule-add-group (name coding-system)
+  "Specify that articles of news group NAME are encoded in CODING-SYSTEM.
+All news groups deeper than NAME are also the target.
+If CODING-SYSTEM is a cons, the car part is used and the cdr
+part is ignored.
+
+This function exists for backward comaptibility with Emacs 20.  It is
+recommended to customize the variable `gnus-group-charset-alist'
+rather than using this function."
+  (if (consp coding-system)
+      ;; Ignore the cdr part because now Gnus can't use different
+      ;; coding systems for encoding and decoding.
+      (setq coding-system (car coding-system)))
+  (let ((tail gnus-group-charset-alist)
+        (prev nil)
+        (pattern (concat "^" (regexp-quote name))))
+    ;; Check entries of `gnus-group-charset-alist' if they match NAME.
+    (while (not (string-match (car (car tail)) name))
+      (setq prev tail tail (cdr tail)))
+    (if tail
+        ;; A matching entry was found.
+        (if (string= pattern (car (car tail)))
+            ;; We can modify this entry.
+            (setcar (cdr (car tail)) coding-system)
+          ;; We must add a new entry before this.
+          (if prev
+              (setcdr prev (cons (list pattern coding-system)
+                                 (cdr prev)))
+            (setq gnus-group-charset-alist
+                  (cons (list pattern coding-system)
+                        gnus-group-charset-alist))))
+      ;; We must prepend a new entry.
+      (setq gnus-group-charset-alist
+            (cons (list pattern coding-system)
+                  gnus-group-charset-alist)))))
+
+(provide 'gnus-mule)
+
+;; gnus-mule.el ends here