Add q60

src/ex/q060.clj

@@ -0,0 +1,20 @@
+;; https://4clojure.oxal.org/#/problem/060
+;; Write a function which behaves like reduce, but returns
+;; each intermediate value of the reduction. Your function
+;; must accept either two or three arguments, and the return
+;; sequence must be lazy.
+
+(ns ex.q060)
+
+(defn ans
+  "Problem 60, Sequence Reductions. restriction: reductions"
+  ([f coll]
+   (lazy-seq
+    (if-let [s (seq coll)]
+      (ans f (first s) (rest s))
+      (list (f)))))
+  ([f val coll]
+   (cons val
+         (lazy-seq
+          (when-let [s (seq coll)]
+            (ans f (f val (first s)) (rest s)))))))

test/ex/q059_test.clj

@@ -9,5 +9,4 @@
     (t/is (= [6] ((sut/ans +) 1 2 3)))
     (t/is (= [21 6 1] ((sut/ans + max min) 2 3 5 1 6 4)))
     (t/is (= ["HELLO" 5] ((sut/ans #(.toUpperCase %) count) "hello")))
-    (t/is (= [2 6 4] ((sut/ans :a :c :b) {:a 2, :b 4, :c 6, :d 8 :e 10})))
-    ))
+    (t/is (= [2 6 4] ((sut/ans :a :c :b) {:a 2, :b 4, :c 6, :d 8 :e 10})))))

test/ex/q060_test.clj

@@ -0,0 +1,11 @@
+;; https://4clojure.oxal.org/#/problem/060
+
+(ns ex.q060-test
+  (:require [clojure.test :as t]
+            [ex.q060 :as sut]))
+
+(t/deftest test-q60
+  (t/testing "Problem 60, Sequence Reductions"
+    (t/is (= [0 1 3 6 10] (take 5 (sut/ans + (range)))))
+    (t/is (= [[1] [1 2] [1 2 3] [1 2 3 4]] (sut/ans conj [1] [2 3 4])))
+    (t/is (= 120 (reduce * 2 [3 4 5]) (last (sut/ans * 2 [3 4 5]))))))