gistfile1.txt

(ns combinatrix.sequence
  (:use combinatrix.core))

(defmonad
  :name    :sequence
  :do      in-sequence
  :bind    (fn [mv f] (mapcat (fn [x] (f x)) mv))
  :return  list
  :zero    ()
  :plus    concat
  :modules [base maybe])

(defn simple-sequence []
  (in-sequence
     x <- (range 3)
     y <- (range 7 11)
     :when (even? y)
     (return [x y])))

(comment
  (simple-sequence)
  => ([0 8] [0 10] [1 8] [1 10] [2 8] [2 10])

  (sum (simple-sequence))
  => (0 8 0 10 1 8 1 10 2 8 2 10))