Did you consider having examples (input-output mappings) be part of the spec for a function, i.e. add an :examples option to the fdef macro in addition to :the current args, :ret, and :fn options? There is nothing really like examples for learning and
clojuredocs.org has been immensely useful for this reason. I figured that especially for functions with simple input-output mappings of primitive data having a few such representative mappings be part of the spec and the doc string would be natural. Those examples could of course also drive tests.