gistfile1.clj

;standard stack consuming fib

(defn fib [n]
  (cond
    (= 0 n) 0
    (= 1 n) 1
    :else (+ (fib (- n 1)) (fib (- n 2)))))

;tail recursive fib using loop-recur
;loop-recur allow you to rebind variables each
;pass through. According to the docs it is the only non stack-consuming
;looping method in closure.
(defn fib-tail [n]
  (loop [num n, a1 0, a2 1]
    (if (= 0 num) a1
        (recur (- num 1), a2, (+ a1 a2)))))