filters.clj

(ns scorewords
  (:use [clojure.test]))

(defn score-sub [words]
  (map (fn [[word n]] [word (if (> n 3)
			      0
			      (/ 1 n))]) (partition 2 (interleave words (iterate inc 2)))))

(defn score-words
  ([term words base]
     (let [[front back] (split-with (partial not= term) words)]
       (concat (reverse (score-sub (reverse front)))
	       [[term base]]
	       (score-sub (rest back)))))
  ([term words]
     (score-words term words 1)))

(deftest test-score-words
  (let [words ["bobby" "fire" "truck" "city" "department" "state" "colorado"]
	multiwords ["bobby" "fire" "jon" "city" "truck" "jon" "department" "state" "colorado"]]
    (is (= [["bobby" 1/3] ["fire" 1/2] ["truck" 1] ["city" 1/2] ["department" 1/3] ["state" 0] ["colorado" 0]]
	   (score-words "truck" words)))
    (is (= [["bobby" 10/3] ["fire" 5] ["truck" 10] ["city" 5] ["department" 10/3] ["state" 0] ["colorado" 0]]
	   (score-words "truck" words 10)))
    (is (= [["bobby 1/3"] ["fire" 1/2] ["jon" 1] ["city" 1/2] ["truck" 1/2] ["jon" 1] ["department" 1/2] ["state" 1/3] ["colorado" 0]]
	   (score-words "jon" multiwords))))