After the seventh round, five more 4clojure.com solutions:

;;; Problem 60 - Sequence Reduction (deftest test-problem-60 (let [v1 (fn fred ([f [p1 & ps]] (fred f p1 ps)) ([f p1 [p2 & ps]] (cons p1 (when p2 (lazy-seq (fred f (f p1 p2) ps)))))) __ v1] (is (= (take 5 (__ + (range))) [0 1 3 6 10])) (is (= (__ conj [1] [2 3 4]) [[1] [1 2] [1 2 3] [1 2 3 4]])) (is (= (last (__ * 2 [3 4 5])) (reduce * 2 [3 4 5]) 120)))) ;;; Problem 59 - Juxtaposition (deftest test-problem-59 (let [v1 (fn [& fns] (fn [& xs] (map #(apply % xs) fns))) __ v1] (is (= [21 6 1] ((__ + max min) 2 3 5 1 6 4))) (is (= ["HELLO" 5] ((__ #(.toUpperCase %) count) "hello"))) (is (= [2 6 4] ((__ :a :c :b) {:a 2, :b 4, :c 6, :d 8 :e 10}))))) ;;; Problem 58 - Function composition (deftest test-problem-58 (let [v1 (fn [& fns] (fn [& xs] (let [[f & rfns] (reverse fns)] (reduce #(%2 %) (apply f xs) rfns)))) v2 (fn [& fns] (reduce (fn [f g] (fn [& xs] (f (apply g xs)))) fns)) __ v2] (is (= [3 2 1] ((__ rest reverse) [1 2 3 4]))) (is (= 5 ((__ (partial + 3) second) [1 2 3 4]))) (is (= true ((__ zero? #(mod % 8) +) 3 5 7 9))) (is (= "HELLO" ((__ #(.toUpperCase %) #(apply str %) take) 5 "hello world"))))) ;;; Problem 57 - Simple Recursion (deftest test-problem-57 (let [v1 [5 4 3 2 1] __ v1] (is (= __ ((fn foo [x] (when (> x 0) (conj (foo (dec x)) x))) 5))))) ;;; Problem 56 - Find Distinct Items (deftest test-problem-56 (let [v1 (fn [xs] (loop [[e & c] xs a [] d #{}] (if e (recur c (if (d e) a (conj a e)) (conj d e)) a))) __ v1] (is (= (__ [1 2 1 3 1 2 4]) [1 2 3 4])) (is (= (__ [:a :a :b :b :c :c]) [:a :b :c])) (is (= (__ '([2 4] [1 2] [1 3] [1 3])) '([2 4] [1 2] [1 3]))) (is (= (__ (range 50)) (range 50))))) (run-tests)