Quick and dirty Trie experiment in Clojure

hacky-trie.clj

(use 'clojure.test)

(def trie (atom {}))

(defn in-trie? [a k]
  (let [key-chars (mapv str (name k))
        xs        (first key-chars)
        ys        (rest  key-chars)]
    (cond
      (and (not-empty ys)
           (nil? (get a (keyword xs))))  false
      (empty? ys)                        (some? (get a (keyword xs)))
      :else                              (recur
                                          (get a (keyword xs))
                                          (keyword (apply str ys))))))

(defn insert-in-trie [k]
  (let [t  @trie
        nt (assoc-in
            t 
            (mapv keyword (map str (name k)))
            1)]
    (reset! trie nt)))

(deftest trie-test
  (testing "hacky trie works as expected"
    (is (= {} @trie))
    (is (false? (in-trie? @trie :dog)))
    (insert-in-trie :dog)
    (is (true? (in-trie? @trie :dog)))
    (is (true? (in-trie? @trie :do)))
    (is (false? (in-trie? @trie :doge)))
    (insert-in-trie :pickle)
    (is (true? (in-trie? @trie :pickle)))
    (is (true? (in-trie? @trie :pick)))
    (is (false? (in-trie? @trie :pickles)))
    ))