Monadic plus for list transformer with set monad

gistfile1.clj

(require '[clojure.algo.monads :as am])
(require '[monads.core :as m])

;-------------- algo.monads version #1 ---------------;

(def set-sequence-m (am/sequence-t am/set-m))

(am/with-monad set-sequence-m
  (am/m-plus #{(list 1 2)} #{(list)} #{(list 3 4)}))

;; => #{() (3 4) (1 2)}

;-------------- algo.monads version #2 ---------------;

(def set-sequence-m (am/sequence-t am/set-m :m-plus-from-transformer))

(am/with-monad set-sequence-m
  (am/m-plus #{(list 1 2)} #{(list)} #{(list 3 4)}))

;; => #{(1 2 3 4)}

;-------------- protocol-monads version --------------;

(def set-list (m/list-t hash-set))

@(m/plus [(set-list 1 2) (set-list) (set-list 3 4)])

;; => #{(1 2 3 4)}