for comprehensions as monad in clojure

gistfile1.clj

(for [x [:a :b :c]
      y [1 2 3]]
  [x y])


(defn bind [mv f] (mapcat f mv))
(bind v1 (fn [x]
           (bind v2 (fn [y]
                      (vector [x y])))))

(defmacro m-do [result
                [sym1 mv1
                 sym2 mv2]
                expression]
  `(bind ~mv1 (fn [~sym1]
                (bind ~mv2 (fn [~sym2]
                             (~result ~expression))))))

(m-do vector [x [:a :b :c]
              y [1 2 3]]
      [x y])

this is from Jim Duey's unsession at clojure conj