Trying to parse nested lists with cgrand's parsley

gistfile1.clj

;; parse nested, punctuated lists in parsley
(def nested-list-parser
  (parser
   :expr #{:e1 [:expr "," :e1]}
   :e1 #{"e" [:e1 ";" "e"]}))
(clojure.pprint/pprint (nested-list-parser "e;e;e,e;e"))