The importance of good documentation cannot be overstated. Clean code is not enough. While it can simplify the process of understanding its behavior unambiguously, it is limited in conveying its intended behavior. If a certain set of inputs doesn't work correctly on a function, is that a bug, or a known/intentional limitation? Tests play an important role in this as well, since they can convey intent in an executable format. Anyway, for what it's worth, I've got my eye on Clojure also.