If all your urls start with http and end with .com
you could write a relatively easy recursive template to
find them, using substrinc-after and substring-before
however if you want to match more general patterns you are really going
to need regexp support, either in an extension function, or in a
pre-pass
eg
sed -e s(_at_)\(http[^ \n,]*\)@<href="\1">\1</a>@g
would pick up all strings starting http up to the next space newline or
comma...
or you could try an implementation of xslt2 draft (saxon7) which has
regexp support built in.
David
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list