+(defun vc-svn-previous-version (file rev)
+ (let ((newrev (1- (string-to-number rev))))
+ (when (< 0 newrev)
+ (number-to-string newrev))))
+
+(defun vc-svn-next-version (file rev)
+ (let ((newrev (1+ (string-to-number rev))))
+ ;; The "workfile version" is an uneasy conceptual fit under Subversion;
+ ;; we use it as the upper bound until a better idea comes along. If the
+ ;; workfile version W coincides with the tree's latest revision R, then
+ ;; this check prevents a "no such revision: R+1" error. Otherwise, it
+ ;; inhibits showing of W+1 through R, which could be considered anywhere
+ ;; from gracious to impolite.
+ (unless (< (string-to-number (vc-file-getprop file 'vc-workfile-version))
+ newrev)
+ (number-to-string newrev))))
+