Rob Ross reports:

Also, on Chapter 3 of the current Logback documentation manual, when it discusses variable substitution it mentions "Recursive Substitution." Well, if you re-read that section carefully I think you'll agree that this example is in fact NOT doing any kind of recursion, it is just using multiple variables. They are not even being nested. So I would suggest calling it something other than "recursion." The people that will read this manual are programmers, and we all know (or should know ) what recursion is, and I think this will just confuse people.

reference http://www.qos.ch/pipermail/logback-user/2008-July/000492.html