Scramboni in Clojure

scramboni.clj

(defn scramboni [rack]
  "Find all playable words in a given Scrabble rack.  Use asterisks for blanks."
  (letfn [(every-but-n? [n pred coll]
            (->> coll
                 (map (comp (fn [x] (if x :true :false)) pred))
                 frequencies
                 (merge {:false 0})
                 :false
                 (>= n)))]
    (let [scrabble-words (->> "/home/mitchells/Desktop/npr_sunday_puzzle_solutions/resources/ospd3.txt"
                              slurp
                              clojure.string/split-lines)
          rack-frequencies (frequencies rack)
          template (zipmap "abcdefghijklmnopqrstuvwxyz" (repeat 26 0))
          points {\a 1 \b 3 \c 3 \d 2 \e 1 \f 4 \g 2 \h 4 \i 1 \j 8 \k 5 \l 1 \m 3
                  \n 1 \o 1 \p 3 \q 10 \r 1 \s 1 \t 1 \u 1 \v 4 \w 4 \x 8 \y 4 \z 10}
          num-asterisks (if-let [n (rack-frequencies \*)] n 0)
          frequencies-to-use (merge template rack-frequencies)
          filtered-words (filter
                           (fn [word] (every-but-n? num-asterisks
                                                    #(<= ((frequencies word) %) 
                                                         (frequencies-to-use %))
                                                    (seq word)))
                           scrabble-words)
         filtered-word-scores (map #(reduce + (map points (seq %))) filtered-words)]
      (->> (zipmap filtered-words filtered-word-scores)
           (sort-by val)
           reverse))))