Add std.uniq, fix #57

Author: sparkprime

doc/stdlib.html

@@ -511,6 +511,11 @@ <h4>std.sort(arr)</h4>
 <p>Sorts the array using the <= operator.</p>
 
 
+<h4>std.uniq(arr)</h4>
+
+<p>Removes successive duplicates.  When given a sorted array, removes all duplicates.</p>
+
+
 <h3>Base 64</h3>
 
 <h4>std.base64(v)</h4>

doc/stdlib.html.jinja

@@ -322,6 +322,11 @@ is suitable for constructing bash scripts and the like.</p>
 <p>Sorts the array using the <= operator.</p>
 
 
+<h4>std.uniq(arr)</h4>
+
+<p>Removes successive duplicates.  When given a sorted array, removes all duplicates.</p>
+
+
 <h3>Base 64</h3>
 
 <h4>std.base64(v)</h4>

std.jsonnet

@@ -765,4 +765,13 @@ limitations under the License.
             local right = std.filter(function(x) x > pivot, rest);
             std.sort(left) + [pivot] + std.sort(right),
 
+    uniq(arr)::
+        local f(a, b) =
+            if std.length(a) == 0 then
+                [b]
+            else if a[std.length(a) - 1] == b then
+                a
+            else
+                a + [b];
+        std.foldl(f , arr, []),
 }

test_suite/stdlib.jsonnet

@@ -255,11 +255,21 @@ std.assertEqual(std.sort([]), []) &&
 std.assertEqual(std.sort([1]), [1]) &&
 std.assertEqual(std.sort([1, 2]), [1, 2]) &&
 std.assertEqual(std.sort([2, 1]), [1, 2]) &&
-std.assertEqual(std.sort(["2", "1"]), ["1", "2"]) &&
+std.assertEqual(std.sort(["1", "2"]), ["1", "2"]) &&
 std.assertEqual(std.sort(["2", "1"]), ["1", "2"]) &&
 std.assertEqual(
     std.sort(["The", "rain", "in", "spain", "falls", "mainly", "on", "the", "plain."]),
     ["The", "falls", "in", "mainly", "on", "plain.", "rain", "spain", "the"]) &&
 
+std.assertEqual(std.uniq([]), []) &&
+std.assertEqual(std.uniq([1]), [1]) &&
+std.assertEqual(std.uniq([1, 2]), [1, 2]) &&
+std.assertEqual(std.uniq(["1", "2"]), ["1", "2"]) &&
+std.assertEqual(
+    std.uniq(["The", "falls", "in", "mainly", "on", "plain.", "rain", "spain", "the"]),
+    ["The", "falls", "in", "mainly", "on", "plain.", "rain", "spain", "the"]) &&
+std.assertEqual(
+    std.uniq(["ant", "bat", "cat", "dog", "dog", "elephant", "fish", "fish", "giraffe"]),
+    ["ant", "bat", "cat", "dog", "elephant", "fish", "giraffe"]) &&
 
 true