karma.clj

karma.clj

;; re http://groups.google.com/group/clojure/browse_thread/thread/55faa29db75192d0

(ns user
  (use [clojure.java.io :only [reader]]))

(def re-vote #"([A-z]{1,16})(\+\+|\-\-)")

(defn extract-votes
  [line]
  (map rest (re-seq re-vote line)))

(defn reckon
  [log]
  (with-open [r (reader log)]
    (let [votes (mapcat extract-votes (line-seq r))]
      (reduce
       (fn [tally [nick vote]]
         (let [inc-or-dec (if (= vote "++") inc dec)]
           (assoc tally nick (inc-or-dec (tally nick 0)))))
       {}
       votes))))

(defn -main [& args]
  (let [tally (->> (ffirst args)
                   reckon
                   (remove (comp zero? val))
                   (sort-by (comp - val)))]
    (doseq [[nick score] tally]
      (println nick score))))

(comment
  
  (-main ["/Users/tin/src/clj/playground/karma.txt"])
  baz 4
  bar 3
  foo -2
  nil

  )

karma.txt

blah foo++ blah
bar++ blah blah blah
blah blah blah baz++ foo-- blah blah
blah bar++ blah blah bar++
blah baz-- baz++ foo-- blah blah
foo--
baz++ blah blah
blah blah baz++
blah baz++ blah
quux++ quux--