Upgrade Twig library

inc/lib/Twig/Node/Expression/Test/Null.php

@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) 2011 Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Checks that a variable is null.
+ *
+ * <pre>
+ *  {{ var is none }}
+ * </pre>
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class Twig_Node_Expression_Test_Null extends Twig_Node_Expression_Test
+{
+    public function compile(Twig_Compiler $compiler)
+    {
+        $compiler
+            ->raw('(null === ')
+            ->subcompile($this->getNode('node'))
+            ->raw(')')
+        ;
+    }
+}