gistfile1.clj

(defn vec->tree [calls]
  (-> (reduce (fn [tree [op was-ret?]]
                (if was-ret?
                  (-> tree
                      (z/append-child op)
                      (z/up))
                  (-> tree
                      (z/append-child [op])
                      (z/down)
                      (z/rightmost))))
              (z/vector-zip [])
              calls)
      (z/root)))

user> (vec->tree '[[(+ (* 2 3) (- 5 2)) nil]
                   [(* 2 3) nil]
                   [6 true]
                   [(- 5 2) nil]
                   [3 true]
                   [4 true]])
[[(+ (* 2 3) (- 5 2)) 
  [(* 2 3) 
   6] 
  [(- 5 2) 
   3] 
  4]]