(interactive
(list
current-prefix-arg
- (string-to-int
- (let ((s (read-string
- (format "Level (default %s): "
- (or (gnus-group-group-level)
- gnus-level-default-subscribed)))))
- (if (string-match "^\\s-*$" s)
- (int-to-string (or (gnus-group-group-level)
- gnus-level-default-subscribed))
- s)))))
+ (progn
+ (unless (gnus-group-process-prefix current-prefix-arg)
+ (error "No group on the current line"))
+ (string-to-int
+ (let ((s (read-string
+ (format "Level (default %s): "
+ (or (gnus-group-group-level)
+ gnus-level-default-subscribed)))))
+ (if (string-match "^\\s-*$" s)
+ (int-to-string (or (gnus-group-group-level)
+ gnus-level-default-subscribed))
+ s))))))
(unless (and (>= level 1) (<= level gnus-level-killed))
(error "Invalid level: %d" level))
(let ((groups (gnus-group-process-prefix n))