gistfile1.txt

(defn all-permutations [things]
  (if (= 1 (count things))
    (list things)
    (for [head things
          tail (all-permutations (disj (set things) head))]
      (do
        (cons head tail)))))

(def items {"mixed fruit"       2.15,
            "french fries"      2.75,
            "side salad"        3.35,
            "hot wings"         3.55,
            "mozzarella sticks" 4.20,
            "sampler plate"     5.80,
            "barbecue"          6.55})

(def target 15.05)

(def combos (all-permutations items))

(defn combo-matches-price? [target combo accum]
  (if (= target (+ (second combo) accum))
    true
    (if (zero? (count (rest combo)))
      false
      (recur target (rest combo) (+ (second combo) accum)))))

(doseq [combo combos]
  (if (combo-matches-price? target (first combo) 0)
    (println "Combo " (pr-str combo) " matches")))