slight alteration to gnus-group-catchup-current

slight alteration to gnus-group-catchup-current

[Dan Christensen]

To catchup all groups in a topic, I put the point on the topic line,
mark the topic with `#', and then hit `c y' only to get the error
message:  "No group on the current line".  The following patch
makes gnus-group-catchup-current a little more forgiving;  it
only complains if it is unable to come up with a list of groups
to catchup, whether from the prefix argument, the region, the
process mark, or the current line.  gnus-group-process-prefix
will now also skip over topic lines gracefully when given a count.

Maybe gnus-group-process-prefix should return all groups in a 
topic when point is on a topic line and there's no prefix, no
active region, and no process-marked articles?

*** gnus-group.el	Thu Nov  6 17:39:45 1997
--- gnus-group.el	Mon Nov 24 16:02:19 1997
***************
*** 1417,1425 ****
  	  (n (abs n))
  	  group groups)
        (save-excursion
! 	(while (and (> n 0)
! 		    (setq group (gnus-group-group-name)))
! 	  (push group groups)
  	  (setq n (1- n))
  	  (gnus-group-next-group way)))
        (nreverse groups)))
--- 1417,1425 ----
  	  (n (abs n))
  	  group groups)
        (save-excursion
! 	(while (> n 0)
! 	  (if (setq group (gnus-group-group-name))
! 	      (push group groups))
  	  (setq n (1- n))
  	  (gnus-group-next-group way)))
        (nreverse groups)))
***************
*** 2401,2416 ****
  
  (defun gnus-group-catchup-current (&optional n all)
    "Mark all articles not marked as unread in current newsgroup as read.
! If prefix argument N is numeric, the ARG next newsgroups will be
  caught up.  If ALL is non-nil, marked articles will also be marked as
  read.  Cross references (Xref: header) of articles are ignored.
! The difference between N and actual number of newsgroups that were
! caught up is returned."
    (interactive "P")
-   (unless (gnus-group-group-name)
-     (error "No group on the current line"))
    (let ((groups (gnus-group-process-prefix n))
  	(ret 0))
      (if (not
  	 (or (not gnus-interactive-catchup) ;Without confirmation?
  	     gnus-expert-user
--- 2401,2415 ----
  
  (defun gnus-group-catchup-current (&optional n all)
    "Mark all articles not marked as unread in current newsgroup as read.
! If prefix argument N is numeric, the next N newsgroups will be
  caught up.  If ALL is non-nil, marked articles will also be marked as
  read.  Cross references (Xref: header) of articles are ignored.
! The number of newsgroups that this function was unable to catch
! up is returned."
    (interactive "P")
    (let ((groups (gnus-group-process-prefix n))
  	(ret 0))
+     (unless groups (error "No groups selected"))
      (if (not
  	 (or (not gnus-interactive-catchup) ;Without confirmation?
  	     gnus-expert-user