Clojure version of Norvig's spell checker for LambdaJam.

speller.clj

(ns spell-checker.speller)


(defonce training-data (re-seq #"[a-z]+" (.toLowerCase (slurp "/home/ckirkendall/Development/clojure/spelling-jam/data/big.txt"))))

(defonce NWORDS (atom (frequencies training-data)))



(defn deletes [word]
   (map #(let [[pre [_ & post]] (split-at % word)]
           (apply str (concat pre post)))
        (range (count word))))

(defn transposes [word]
   (map #(let [[pre [a b & post]] (split-at % word)]
           (apply str (concat pre [b a] post)))
        (range (dec (count word)))))
    
(defn replaces [word] 
  (let [wrd (vec word)]
   (for [ch "abcdefghijklmnopqrstuvwxyz" i (range (count wrd))]
     (apply str (assoc wrd i ch)))))

(defn inserts [word]
  (for [ch "abcdefghijklmnopqrstuvwxyz" i (range (count word))]
    (let [[pre post] (split-at i word)]
         (apply str (concat pre (cons ch post))))))

(defn edits1 [word]  
    (set (concat (deletes word)
            (transposes word)
            (replaces word)
            (inserts word))))


(defn edits2 [word]
  (set (mapcat #(edits1 %) (edits1 word))))


(defn known [words] (filter @NWORDS words))

(defn correct [word]
   (let [w (known [word])
         w (if (empty? w) (known (edits1 word)) w)
         w (if (empty? w) (known (edits2 word)) w)
         w (if (empty? w) [word] w)]
     (sort-by @NWORDS w)))
     


(def test1 (rest (map #(re-seq #"[a-z]+" %) (line-seq  (clojure.java.io/reader "/home/ckirkendall/Development/clojure/spelling-jam/data/test1.txt")))))

(def test2 (rest (map #(re-seq #"[a-z]+" %) (line-seq  (clojure.java.io/reader "/home/ckirkendall/Development/clojure/spelling-jam/data/test2.txt")))))


(defn testing-speller [test-data]
  (reduce #(let [[c i] %1
                 [expected & tail] %2
                 cor  (count 
                       (filter (fn [word] 
                                 (= expected (first (correct word)))) tail))]
             [(+ c (count tail)) (+ i (- (count tail) cor))])
          [0 0]
          test-data))

(defn add-word [word]
  (swap! NWORDS assoc word 1))

(testing-speller test2)
    
(correct "exstacy")

(correct "hizzy")
(add-word "hizzy")