let statement in joining sto lines

gistfile1.clj

(let [[nm sq] (cond
                                            (.startsWith l "#=GC SS_cons")
                                            [(str/join " " (butlast (str/split #"\s+" l))) (last (str/split #"\s+" l))] ;;splits the line apart and hopefully creates vector  ["#GC SS_cons" structure]
                                            (.startsWith l "#")
                                            (str/split #"\s{2,}+" l)
                                            :else
                                            (str/split #"\s+" l))
                                   prev (get m nm [(gen-uid) ""])]
                               (assoc m  nm [(first prev)
                                             (str (second prev) sq)]))