on matching more naked URLs in articles

[Steinar Bang <sb@metis.no>]

Before I waste time on it: has anyone looked into changing
gnus-button-url-regexp into matching naked URLs without a protocol
field?  Ie. URLs like dodrt.dod.no, vvv.no, imdb.com etc.

And is there a way to getting the changed gnus-button-url-regexp into
gnus-button-alist without restarting Gnus?  (I suspect that ever
longer and more cryptic regexps require quick cycles of changing and
trying)

Todays gnus-button-url-regexp is 
 "\\b\\(s?https?\\|ftp\\|file\\|gopher\\|news\\|telnet\\|wais\\|mailto\\):\\(//[-a-zA-Z0-9_.]+:[0-9]*\\)?\\([-a-zA-Z0-9_=!?#$@~`%&*+|\\/:;.,]\\|\\w\\)+\\([-a-zA-Z0-9_=#$@~`%&*+|\\/]\\|\\w\\)"

I'm not sure where the best place to change it is.  My first attempt
would be something like this:
 "\\b\\(\\(s?https?\\|ftp\\|file\\|gopher\\|news\\|telnet\\|wais\\|mailto\\):\\(//[-a-zA-Z0-9_.]+:[0-9]*\\)?\\([-a-zA-Z0-9_=!?#$@~`%&*+|\\/:;.,]\\|\\w\\)+\\([-a-zA-Z0-9_=#$@~`%&*+|\\/]\\|\\w\\)\\|\\([A-Za-z]+\\.\\)+\\(com\\|org\\|no\\|se\\)\\(/[A-Za-z0-9/]+\\)?\\)"

I'm not sure if the top level domain should be from a fixed list, or
if we just should match [A-Za-z]?  Are there efficiency reasons for
doing it either way?

Most URLs exchanged this way seems to be .com URLs or URLs in the
native national domain of a particular newsgroup.