Merge commit '6d1a' into develop

flatland · Oct 10, 2014 · 2cce067 · 2cce067
2 parents b655e5b + 6d1a6fb
commit 2cce067
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Showing 2 changed files with 13 additions and 2 deletions.
diff --git a/src/flatland/useful/fn.clj b/src/flatland/useful/fn.clj
@@ -132,9 +132,9 @@
   (transform y)."
   ([modifier]
      (fn [a b]
-       (- (modifier a) (modifier b))))
+       (compare (modifier a) (modifier b))))
   ([direction modifier]
-     (let [f (comparator modifier)]
+     (let [f (key-comparator modifier)]
        (condp #(% %2) direction
          #{:desc :descending -} (comp - f)
          #{:asc :ascending +} f))))

diff --git a/test/flatland/useful/fn_test.clj b/test/flatland/useful/fn_test.clj
@@ -79,3 +79,14 @@
 
 (deftest test-ignoring-nils
   (is (= 6 ((ignoring-nils +) 1 nil 2 nil nil 3))))
+
+(deftest test-key-comparator
+  (let [subtract-comparator-fn-breaks-on-this [2147483650 2147483651
+                                               2147483652 4 2 3 1]
+        normal-cmp (key-comparator identity)]
+    (is (= (sort subtract-comparator-fn-breaks-on-this)
+           (sort normal-cmp subtract-comparator-fn-breaks-on-this))))
+  (let [square (fn [x] (* x x))
+        by-square (key-comparator :ascending square)]
+    (is (= (sort-by square [-9 -5 1 -2])
+           (sort by-square [-9 -5 1 -2])))))