Check if a string contains balanced parenthesis in Clojure

parens.clj

(def openning ["(" "[" "{"])
(def closing [")" "]" "}"])
(def parens (zipmap openning closing))

(defn parens-balanced?
  [s]
  (loop [input-string s
         stack []]
    (if (empty? input-string)
      (empty? stack)
      (let [character (str (first input-string))
            rest-str (apply str (rest input-string))]
        (cond
          (some #(= character %) openning)
          (recur rest-str (conj stack (get parens character)))
          (some #(= character %) closing)
          (if (or (empty? stack) (not= (last stack) character))
            false
            (recur rest-str (pop stack)))
          :else (recur rest-str stack))))))