clojure_loop.clj

(loop [i 0]
  (if (< i 10)
    (recur (inc 1))
    i))

(str "2 is " (if (even? 2) "even" "odd"))

(if (true? false) "impossible!")
 
(defn factorial [x]
  (with-local-vars [acc 1, cnt x]
    (while (> @cnt 0)
      (var-set acc (* @acc @cnt))
      (var-set cnt (dec @cnt)))
    @acc))
 
;looping is recursive in Clojure, the loop construct is a hack so that something like tail-recursive-optimization works in clojure.
(defn my-re-seq [re string]
  "Something like re-seq"
  (let [matcher (re-matcher re string)]

    (loop [match (re-find matcher) ;loop starts with 2 set arguments
           result []]
      (if-not match
        result
        (recur (re-find matcher)    ;loop with 2 new arguments
               (conj result match))))))


(my-re-seq #"\d" "0123456789")

(if (even? 5)
  (do (println "even")
    true)
  (do (println "odd")
    false))

(if-let [x (even? 3)]
  (println x)
  (println "some odd value"))

(range 10)

(filter even? (range 10))

(str "see: " (seq (filter even? [1 2 3])))


;empty list () will be true, seq will return nil
(defn show-evens [coll]
  (if-let [evens (seq (filter even? coll))]
    (println (str "the evens are: " evens))
    (println "There were no evens.")))

(show-evens [2 2])