Clojure meetup final

gistfile1.clj

;; Anything you type in here will be executed
;; immediately with the results shown on the
;; right.



(def data '({:name "nick" :age 20} {:name "george", :age 30}
            {:name "giannis", :age 40} {:name "dimitris", :age 50}))




(defn map' [f source]
  (fn [k]
    (source (fn [x acc] (k (f x) acc)))))


(defn filter' [pred source]
  (fn [k]
    (source (fn [x acc]
              (if (pred x)
                (k x acc)
                acc)))))

(defn reduce' [f acc source]
  ((source f) acc))

(defn toList [source]
  (reduce' (fn [x acc] (cons x acc))
           '() source))

(defn build [source]
  (fn [k]
    (fn [acc]
      (defn reduce'' [source]
        (if (empty? source)
          acc
          (k (first source)
             (reduce'' (rest source)))))
      (reduce'' source))))


(defn transform-name-upper [source]
  (toList (map'(fn [first'] (.toUpperCase (:name first')))
             (build source))))

(defn transform-inc-age [source]
    (map'(fn [first'] (inc (:age first')))
       source))

(transform-name-upper data)

(transform-inc-age data)




(defn find-by-age [source age]
  (filter' (fn [first'] (= (:age first') age))
    source))

(defn find-by-name [source name]
  (filter' (fn [first'] (= (:name first') name))
    source))

(find-by-age data 30)
(find-by-name data "nick")


;;(f (f ..... acc))
;; (f.... (f (f acc)
(defn length [source]
  (reduce' (fn [x acc] (+ 1 acc)) 0 source))


(defn sum-age [source]
  (reduce' (fn [x acc] (+ (:age x) acc)) 0 source))

(length data)
(sum-age data)

(defn sum-inc-age [source]
  (reduce' + 0
    (map' (fn [x] (inc (:age x))) source)))


(sum-inc-age data)