and the <tt>˜n</tt> pattern:
<verb>
-color black yellow "~n 10-"
-color red yellow "~n 100-"</verb>
+color index black yellow "~n 10-"
+color index red yellow "~n 100-"</verb>
<p>The rules above mark all messages with a score between 10 and 99
with black and yellow, and messages with a score greater or equal