Ch135 (Clojure): Task 1

2 files changed, 28 insertions, 3 deletions

diff --git a/challenge-135/tyler-wardhaugh/clojure/src/tw/weekly/c135/t1.clj b/challenge-135/tyler-wardhaugh/clojure/src/tw/weekly/c135/t1.clj
index 1ab26e6eb5..0ff0714a19 100644
--- a/challenge-135/tyler-wardhaugh/clojure/src/tw/weekly/c135/t1.clj
+++ b/challenge-135/tyler-wardhaugh/clojure/src/tw/weekly/c135/t1.clj
@@ -7,9 +7,31 @@
 ;;;
 (def DEFAULT-INPUT [1234567])
 
+(defn abs
+  "Return the absolute value of n."
+  [n]
+  (if (pos? n) n (- n)))
+
+(defn middle-3
+  "Find the middle 3-digits of the given integer n if possible, otherwise throw
+  a sensible error."
+  [n]
+  {:pre [(int? n)]}
+  (let [sn (-> n abs str)
+        len (count sn)]
+    (cond
+      (even? len) (throw (ex-info "even number of digits" {"length" len}))
+      (< len 3) (throw (ex-info "too short" {"length" len}))
+      :else (subs sn (dec (/ len 2)) (+ 2 (/ len 2))))))
+
 (defn -main
   "Run Task 1 with a given input N, defaulting to the first example from the
   task description."
   [& args]
   (let [[N] (or (some->> args (map edn/read-string)) DEFAULT-INPUT)]
-    ))
+    (try
+      (println (middle-3 N))
+      (catch Exception e
+        (cl-format true "error: ~a (~:{~a=~s~^, ~})~%"
+                   (.getMessage e)
+                   (ex-data e))))))
diff --git a/challenge-135/tyler-wardhaugh/clojure/test/tw/weekly/c135/t1_test.clj b/challenge-135/tyler-wardhaugh/clojure/test/tw/weekly/c135/t1_test.clj
index f6dfa90c7d..707a9162cd 100644
--- a/challenge-135/tyler-wardhaugh/clojure/test/tw/weekly/c135/t1_test.clj
+++ b/challenge-135/tyler-wardhaugh/clojure/test/tw/weekly/c135/t1_test.clj
@@ -1,7 +1,10 @@
 (ns tw.weekly.c135.t1-test
   (:require [clojure.test :refer [deftest is testing]]
-            #_[tw.weekly.c135.t1 :refer []]))
+            [tw.weekly.c135.t1 :refer [middle-3]]))
 
 (deftest examples
   (testing "Examples from description"
-    ))
+    (is (= "345" (middle-3 1234567)))
+    (is (= "123" (middle-3 -123)))
+    (is (thrown-with-msg? Exception #"too short" (middle-3 1)))
+    (is (thrown-with-msg? Exception #"even number of digits" (middle-3 10)))))