reconstitution of de-normalized hashes (1 level deep only)

parser.clj

(defn parse-de-normalized-list [items]
  (let [r #"^.+::.+$"
        reducer (fn [prod item]
          (if-not (re-find r (:code item))
            (let [child-r (re-pattern (str "^" (:code item) "::.+$"))
                  children (filter #(re-find child-r (:code %1)) items)
                  new-item (merge item {:children (vec children)})]
              (merge prod new-item))
            prod))]
    (reduce reducer [] items)))

(def normalized (parse-de-normalized-list [
  {:code "INT" :name "Internet"}
  {:code "BRK" :name "Breakfast"}
  {:code "BRK::FRBRK" :name "Complimentary"}
  {:code "POOL" :name "Pool"}
  {:code "POOL::OPOOL" :name "Outdoor"}]))

(prn normalized) => [
  {:children [], :code "INT", :name "Internet"}
  {:children [{:code "BRK::FRBRK", :name "Complimentary"}],
    :code "BRK", :name "Breakfast"}
  {:children [{:code "POOL::OPOOL", :name "Outdoor"}],
    :code "POOL", :name "Pool"}]