--- /dev/null
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+/**
+ * Twig_NodeVisitorInterface is the interface the all node visitor classes must implement.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+interface Twig_NodeVisitorInterface
+{
+ /**
+ * Called before child nodes are visited.
+ *
+ * @return Twig_NodeInterface The modified node
+ */
+ public function enterNode(Twig_NodeInterface $node, Twig_Environment $env);
+
+ /**
+ * Called after child nodes are visited.
+ *
+ * @return Twig_NodeInterface|false The modified node or false if the node must be removed
+ */
+ public function leaveNode(Twig_NodeInterface $node, Twig_Environment $env);
+
+ /**
+ * Returns the priority for this visitor.
+ *
+ * Priority should be between -10 and 10 (0 is the default).
+ *
+ * @return int The priority level
+ */
+ public function getPriority();
+}