[feature-request] Support for xpat

[Frank Schmitt <usereplyto@Frank-Schmitt.net>]

Hello all

There's one thing I'm missing in Gnus which offered my last newsreader
(XNews) and this is support for the xpat command. This command is
implemented in most modern newsserver and allows searching for messages
with a given pattern in some header.

Say you want all articles in gnus.ding which include the words foo and
bar, you can then do the following:

group gnus.ding
xpat Subject 1234-4321 *foo*bar*

and the server will return article number and full header for every
matching article.

What I would like to have is something like this:

M-x gnus-xpat-search
<-Which header?
->Subject
<-Articles from 1234 to 5432 present, please enter min of range
(default: 1234).
->RET
<-Articles from 1234 to 5432 present, please enter max of range
(default: 5432).
->4321
<-Which pattern?
->*foo*bar*

Now Gnus should build a summary buffer with all articles which matched
and present it.

The benefit of this would be, that you can search in really big groups
without having to actually enter them, what can take several minutes if
the group is really big (some 10k messages).

-- 
One Ring to rule them all, One Ring to find them,
One Ring to bring them all and in the darkness bind them
In the Land of Mordor where the Shadows lie.