user> (def x (reify ))
#'user/x
user> x
#object[user$reify__18893 0x555a4e7 "user$reify__18893@555a4e7"]
user> (class x)
user$reify__18893
user> (defprotocol P (foo [_]))
P
user> (extend (class x) P {:foo (fn [_] (prn :foo))})
nil
user> (foo x)
:foo
nil
user>

(defn x [] (reify))

(defn x [ctx]
  (reify ...))

(def obj1 (x :foo))
(def obj2 (x :bar))

;; ~~~~~~~~~~~~~~~~

(defn ->obj1 []
  (reify ...))

(defn ->obj2 []
  (reify ...))

(def obj1 (->obj1))
(def obj2 (->obj2))