ll.clj

(definterface INode
  (getCar [])
  (getCdr [])
  (setCar [x])
  (setCdr [x]))

(deftype Node [^:volatile-mutable car ^:volatile-mutable cdr]
  INode
  (getCar [_] car)
  (getCdr [_] cdr)
  (setCar [this x] (set! car x))
  (setCdr [this x] (set! cdr x))
  clojure.lang.ISeq
  (first [this] this)
  (next [_] cdr))

(defn new-node [car & [cdr]]
  (Node. car cdr))

(defn list-eval [l]
  (let [l (reverse l)]
    (loop [cur (first l) more (next l) nodes nil]
      (if-not cur
        nodes
        (recur (first more) (next more) (new-node cur nodes))))))

(prn (-> (list-eval (list 1 2 3 4)) first .getCar))  ;; => 1