internal-reduce implementation for String

mikera · Dec 2, 2011 · 9866d59 · 9866d59
1 parent 7ab01ab
commit 9866d59
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Showing 2 changed files with 14 additions and 2 deletions.
diff --git a/src/clj/clojure/core/protocols.clj b/src/clj/clojure/core/protocols.clj
@@ -71,6 +71,15 @@
 	         (internal-reduce s f val))
 	       val)))
 
+  java.lang.String
+  (internal-reduce
+   [s f val]
+    (loop [i 0
+           val val]
+       (if (< i (.length s))
+         (recur (inc i) (f val (.charAt s i)))
+         val)))
+
   java.lang.Object
   (internal-reduce
    [s f val]

diff --git a/test/clojure/test_clojure/reduce.clj b/test/clojure/test_clojure/reduce.clj
@@ -27,7 +27,7 @@
   (is (= 1 (reduce multiply 1 (char-array 0)))))
 
 (deftest test-map-reductions
-  ;reduce over a large map
+  ;reduce over a 100-element map
   (let [ms (zipmap (range 100) (range 100))]
     (is (= 4950 (reduce (fn [acc [k v]] (+ acc v)) 0 ms)))))
 
@@ -47,4 +47,7 @@
   ; reduce on two-element collections applies function once
   (is (= 6 (reduce multiply [2 3])))
   (is (= 6 (reduce multiply '(2 3))))
-  (is (= 6 (reduce multiply #{2 3}))))
+  (is (= 6 (reduce multiply #{2 3}))))
+
+(deftest test-string-reductions
+  (is (= "Hello World" (reduce str "" "Hello World"))))