fix dot

Author: loganhenson

src/Vector/Lib/Lambda.php

@@ -25,7 +25,7 @@ protected static function __pipe(...$fs)
 
     protected static function __dot($f, $g)
     {
-        return function($x) {
+        return function ($x) use ($f, $g) {
             return $f($g($x));
         };
     }

tests/Lib/LambdaTest.php

@@ -4,6 +4,7 @@
 
 use Vector\Core\Module;
 use Vector\Lib\Lambda;
+use Vector\Lib\Math;
 
 class LambdaTest extends \PHPUnit_Framework_TestCase
 {
@@ -104,4 +105,11 @@ public function testFlip()
         $this->assertEquals(4, $subtract(2, 6)); // 6 - 2
         $this->assertEquals(-4, $flippedSubtract(2, 6)); // 2 - 6
     }
+
+    public function testDot()
+    {
+        $add2ThenAdd1 = Lambda::dot(Math::add(1), Math::add(2));
+
+        $this->assertEquals(3, $add2ThenAdd1(0));
+    }
 }