| NodeVisitorInterface | Twig_NodeVisitorInterface is the interface the all node visitor classes must implement. |
| AbstractNodeVisitor | Twig_BaseNodeVisitor can be used to make node visitors compatible with Twig 1.x and 2.x. |
| EscaperNodeVisitor | Twig_NodeVisitor_Escaper implements output escaping. |
| OptimizerNodeVisitor | Twig_NodeVisitor_Optimizer tries to optimizes the AST. |
| SafeAnalysisNodeVisitor | Twig_BaseNodeVisitor can be used to make node visitors compatible with Twig 1.x and 2.x. |
| SandboxNodeVisitor | Twig_NodeVisitor_Sandbox implements sandboxing. |
