to-json-problem.clj

(ns org.example.playground.handler.visitor)

(defmulti ->json type)

(defmethod ->json java.lang.Boolean
  [x]
  (str x))

(defmethod ->json java.lang.Long
  [x]
  (str x))

(defmethod ->json clojure.lang.PersistentVector
  [x]
  (->> (concat ["["] (interpose ", " (map ->json x)) ["]"])
       (reduce str "")))

(defmethod ->json :default
  [x]
  (str x))

(comment
  (->json [1 2 3]))