Mark,
Thanks for the feedback.

Kai- You're right that gnus-remove-from-range is effectively the 
gnus-range-difference that I wrote.  I have found one critical 
difference; gnus-range-difference creates a new range rather than 
editing the original range1.  The gnus-summary-insert-old-articles 
function passes gnus-newsgroup-active so there is a chance that 
gnus-remove-from-range might corrupt the active range.  Calling 
gnus-remove-from-range would have otherwise worked except that I 
introduced a new bug with the rest of my changes.  I've attached a patch 
for gnus-sum.el (version 6.241) below that will get 
gnus-summary-insert-old-articles working with gnus-range-difference. 
 I've also attached a patch for adding gnus-range-difference to 
gnus-range.el (version 6.12).

Kevin

Kai Großjohann wrote:

>Mark Triggs <mst@dishevelled.net> writes:
>
>  
>
>>After applying the patch, I seem to get the following:
>>
>>  Debugger entered--Lisp error: (wrong-type-argument number-or-marker-p (4882 . 5694))
>>    gnus-sorted-difference(((4882 . 5694) (5698 . 5700)) (5695 5696 5697))
>>    gnus-summary-insert-articles(((4882 . 5694) (5698 . 5700)))
>>    gnus-summary-insert-old-articles(nil)
>>    call-interactively(gnus-summary-insert-old-articles)
>>    
>>
>
>Could you apply the following patch on top of the previous one?
>I even tested it once :-)
>
>--- gnus-sum.el	2002/11/21 07:43:41	6.238.1.1
>+++ gnus-sum.el	2002/11/25 07:26:57
>@@ -11178,7 +11178,8 @@
> ;;;	      (gnus-sorted-difference
> ;;;	       (gnus-uncompress-range (list gnus-newsgroup-active))
> ;;;	       old)
>-              (gnus-range-difference (list gnus-newsgroup-active) old)
>+	      (gnus-uncompress-range
>+	       (gnus-remove-from-range (list gnus-newsgroup-active) old))
> )
> 	(setq len (gnus-range-length older))
> 	(cond
>
>kai
>  
>