Merge pull request #137 from haus/add_all-your-base_exercise

Add all-your-base exercise

config.json

@@ -45,6 +45,7 @@
     "binary-search-tree",
     "difference-of-squares",
     "hexadecimal",
+    "all-your-base",
     "largest-series-product",
     "pov",
     "bracket-push",

exercises/all-your-base/project.clj

@@ -0,0 +1,4 @@
+(defproject all-your-base "0.1.0-SNAPSHOT"
+  :description "all-your-base exercise."
+  :url "https://github.com/exercism/xclojure/tree/master/exercises/all-your-base"
+  :dependencies [[org.clojure/clojure "1.8.0"]])

exercises/all-your-base/src/example.clj

@@ -0,0 +1,31 @@
+(ns all-your-base)
+
+(defn- digits->decimal
+  "Converts a sequence of digits given in input-base into decimal format."
+  [input-base digits]
+  (loop [sum 0
+         [num & nums] digits]
+    (if num
+      (recur (+ (* sum input-base) num) nums)
+      sum)))
+
+(defn- decimal->digits
+  "Converts a decimal number into a sequence of digits in the desired output base."
+  [output-base number]
+  (loop [digits nil
+         num number]
+    (if (zero? num)
+      digits
+      (recur (conj digits (mod num output-base)) (quot num output-base)))))
+
+(defn convert
+  "Converts a sequence of digits given in input-base into a sequence of digits in the desired output-base."
+  [input-base digits output-base]
+  (cond
+    (some #(< % 2) (list input-base output-base)) nil
+    (not-every? #(and (not (neg? %)) (< % input-base)) digits) nil
+    (empty? digits) ()
+    (every? #(zero? %) digits) '(0)
+    :else (->> digits
+               (digits->decimal input-base)
+               (decimal->digits output-base))))

exercises/all-your-base/test/all_your_base_test.clj

@@ -0,0 +1,87 @@
+(ns all-your-base-test
+  (require [clojure.test :refer [deftest testing is]]
+           [all-your-base]))
+
+(deftest test-single-bit-to-one-decimal
+  (testing "Base 2 '1' converts to base 10 '1'"
+    (is (= '(1) (all-your-base/convert 2 '(1) 10)))))
+
+(deftest test-binary-to-single-decimal
+  (testing "Base 2 '1 0 1' converts to base 10 '5'"
+    (is (= '(5) (all-your-base/convert 2 '(1 0 1) 10)))))
+
+(deftest test-single-decimal-to-binary
+  (testing "Base 10 '5' converts to base 2 '1 0 1'"
+    (is (= '(1 0 1) (all-your-base/convert 10 '(5) 2)))))
+
+(deftest test-binary-to-multiple-decimal
+  (testing "Base 2 '1 0 1 0 1 0' converts to base 10 '4 2'"
+    (is (= '(4 2) (all-your-base/convert 2 '(1 0 1 0 1 0) 10)))))
+
+(deftest test-decimal-to-binary
+  (testing "Base 10 '4 2' conves to base 2 '1 0 1 0 1 0'"
+    (is (= '(1 0 1 0 1 0) (all-your-base/convert 10 '(4 2) 2)))))
+
+(deftest test-trinary-to-hexadecimal
+  (testing "Base 3 '1 1 2 0' converts to base 16 '2 10'"
+    (is (= '(2 10) (all-your-base/convert 3 '(1 1 2 0) 16)))))
+
+(deftest test-hexadecimal-to-trinary
+  (testing "Base 16 '2 10' converts to base 3 '1 1 2 0'"
+    (is (= '(1 1 2 0) (all-your-base/convert 16 '(2 10) 3)))))
+
+(deftest test-15-bit-integer
+  (testing "Base 97 '3 46 60' converts to base 73 '6 10 45'"
+    (is (= '(6 10 45) (all-your-base/convert 97 '(3 46 60) 73)))))
+
+(deftest test-empty-list
+  (testing "Empty input digits returns empty sequence"
+    (is (empty? (all-your-base/convert 2 () 10)))))
+
+(deftest test-single-zero
+  (testing "0 converts to 0, no matter the base"
+    (is (= '(0) (all-your-base/convert 10 '(0) 2)))))
+
+(deftest test-multiple-zeroes
+  (testing "0 converts to 0, no matter the how many zeroes"
+    (is (= '(0) (all-your-base/convert 10 '(0 0 0) 2)))))
+
+(deftest test-leading-zeros
+  (testing "Leading zeroes don't affect conversion"
+    (is (= '(4 2) (all-your-base/convert 7 '(0 6 0) 10)))))
+
+(deftest test-negative-digit
+  (testing "Negative digits result in nil"
+    (is (nil? (all-your-base/convert 2 '(1 -1 1 0 1 0) 10)))))
+
+(deftest test-invalid-positive-digit
+  (testing "Invalid digits return nil"
+    (is (nil? (all-your-base/convert 2 '(1 2 1 0 1 0) 10)))))
+
+(deftest test-first-base-is-one
+  (testing "Input base of 1 returns nil"
+    (is (nil? (all-your-base/convert 1 () 10)))))
+
+(deftest test-second-base-is-one
+  (testing "Output base of 1 returns nil"
+    (is (nil? (all-your-base/convert 2 '(1 0 1 0 1 0) 1)))))
+
+(deftest test-first-base-is-zero
+  (testing "Input base of 0 returns nil"
+    (is (nil? (all-your-base/convert 0 () 10)))))
+
+(deftest test-second-base-is-zero
+  (testing "Output base of 0 returns nil"
+    (is (nil? (all-your-base/convert 10 '(7) 0)))))
+
+(deftest test-first-base-is-negative
+  (testing "Negative input base returns nil"
+    (is (nil? (all-your-base/convert -2 '(1) 10)))))
+
+(deftest test-second-base-is-negative
+  (testing "Negative output base returns nil"
+    (is (nil? (all-your-base/convert 2 '(1) -7)))))
+
+(deftest test-both-bases-are-negative
+  (testing "When both bases are negative, nil is returned"
+    (is (nil? (all-your-base/convert -2 '(1) -7)))))