http://www.slipp.net/wiki/pages/viewpage.action?pageId=16711765 에서 계산기에 대해 여러가지로 작성해보았습니다.

slipp-clojure-3th.clj

(use ['clojure.string])
(defn t [actual expected]
    (if (= actual expected)
        (do
           (println 'sucess)
         true )
       (do
           (println (str 'fail!! " actual: " actual " expected " expected ))
         false)))
(t 1 1)
(t 1 0)

(#(reduce %1 %2) + '(1 2 3 4 5))

(#(reduce %1 %2) + (map read-string (split "1,2,3" #",")))

(defn add [text] (#(reduce %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text #",") )))

(map #(if (empty? %) 0 (read-string %)) (split "1,2" #","))
(add "")
(add "1,2,4")
(add "1,2")


(defn add2
  ([form]
     (#(reduce %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split form #",") )))
  ([text sep]
     (#(reduce %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))
  )

(add2 "" ",")
(add2 "1,2,4" ",")
(add2 "1,2" ",")


(defn add3
  ([form]
     (cond
      (= "" form) 0
      (.startsWith form "//")
        (let [matchs (re-find (re-pattern "^//(.)\n(.*)") form)]
          (add3 (last matchs) (second matchs) ) )
      :else (add3 form ",") ))

  ([text sep]
     (#(reduce %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))
  )

(add3 "")
(add3 "1,2,4")
(add3 "1,2")
(add3 "//:\n1")
(add3 "//:\n1:2:3")


(defn add4
  [form]

  (defn _reduce [text sep]
       (#(reduce %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))

  (cond
      (= "" form) 0
      (.startsWith form "//")
        (let [matchs (re-find (re-pattern "^//(.)\n(.*)") form)]
          (_reduce (last matchs) (second matchs) ) )
      :else (_reduce form ",") ))


(add4 "")
(add4 "1,2,4")
(add4 "1,2")
(add4 "//:\n1")
(add4 "//:\n1:2:3")


(defn add5
  [form]

  (defn _apply [text sep]
       (#(apply %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))

  (cond
      (= "" form) 0
      (.startsWith form "//")
        (let [matchs (re-find (re-pattern "^//(.)\n(.*)") form)]
          (_apply (last matchs) (second matchs) ) )
      :else (_apply form ",") ))



(add5 "")
(add5 "1,2,4")
(add5 "1,2")
(add5 "//:\n1")
(add5 "//:\n1:2:3")

(_apply "1,2,3" ",") ;;헛

(defn add6
  [form]
  (let [_apply (fn [text sep] (#(apply %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))]
    (cond (= "" form) 0 
          (.startsWith form "//") (let [matchs (re-find (re-pattern "^//(.)\n(.*)") form)] (_apply (last matchs) (second matchs) ) )
          :else (_apply form ",") ))    
  )
  

(add6 "")
(add6 "1,2,4")
(add6 "1,2")
(add6 "//:\n1")
(add6 "//:\n1:2:3")


(re-matches #"^//(.)\n(.*)" "//:\n1:2:3")
(re-find (re-pattern #"^//(.)\n(.*)") "//:\n1:2:3")

(defn add7
  [form]
  (let [_apply (fn [text sep] (#(apply %1 %2) + (map #(if (empty? %) 0 (read-string %)) (split text (re-pattern sep)) )))]
    (cond (= "" form) 0 
          (.startsWith form "//") (let [matchs (re-matches #"^//(.)\n(.*)" form)] (_apply (last matchs) (second matchs) ) )
          :else (_apply form ",") ))    
  )

(add7 "")
(add7 "1,2,4")
(add7 "1,2")
(add7 "//:\n1")
(add7 "//:\n1:2:3")



(re-matcher #"^//(.)\n(.*)" "//:\n1:2:3")
(class (re-matcher #"^//(.)\n(.*)" "//:\n1:2:3"))
(.find (re-matcher #"^//(.)\n(.*)" "//:\n1:2:3"))
(-> (re-matcher #"^//(.)\n(.*)" "//:\n1:2:3").find)

(def p (re-pattern #"^//(.)\n(.*)"))
(-> (re-matcher p "//:\n1:2:3").find)

(def validate #(-> (re-matcher p %).find))
(validate "//:\n1:2:3")

(def validate #(let [_p (re-pattern #"^//(.)\n(.*)")] (-> (re-matcher _p %).find)))
(validate "//:\n1:2:3")

(defn parse [form] 
  (if (validate form)
    (let [matches (re-matches p form)
        sep (nth matches 1)
        text (nth matches 2)] 
    (map #(read-string %) (split text (re-pattern sep))))))

(parse "//:\n1:2:3")
(apply + (parse "//:\n1:2:3"))