Reducing some stuff into a tree

gistfile1.clj

(defrecord Tree [id pid children])

(def comments [{:id 1 :pid 0}
               {:id 2 :pid 1}
               {:id 3 :pid 1}
               {:id 4 :pid 3}
               {:id 5 :pid 3}
               {:id 6 :pid 3}
               {:id 7 :pid 2}
               {:id 8 :pid 7}])

(defn tree-insert [x t]
  (if (= (:pid x) (:id t))
    (assoc t :children (conj (:children t) x))
    (assoc t :children (map (partial tree-insert x) (:children t)))))

(tree-insert (Tree. 2 1 nil) (tree-insert (Tree. 1 0 nil) (Tree. 0 nil nil)))

(def the-tree
  (reduce (fn [t x]
            (tree-insert x t))
          (map map->Tree comments)))