+(defun mdw-version-< (ver-a ver-b)
+ "Answer whether VER-A is strictly earlier than VER-B.
+VER-A and VER-B are version numbers, which are strings containing digit
+sequences separated by `.'."
+ (let* ((la (mapcar (lambda (x) (car (read-from-string x)))
+ (split-string ver-a "\\.")))
+ (lb (mapcar (lambda (x) (car (read-from-string x)))
+ (split-string ver-b "\\."))))
+ (catch 'done
+ (while t
+ (cond ((null la) (throw 'done lb))
+ ((null lb) (throw 'done nil))
+ ((< (car la) (car lb)) (throw 'done t))
+ ((= (car la) (car lb)) (setq la (cdr la) lb (cdr lb))))))))
+