Is there any tool to generate UML diagrams based on a custom grammar?

I need a tool/lib to generate UML diagrams from source of a custom programming language grammar. Is there a tool with API or another method to relatively easily tell to generator how it should to interpret the grammar. 开发者_如何学PythonI have full control of the programming language lexer.

Ask to specific clarification if you have some doubts.

Looks like a plain AST visitor should do, shouldn't it? Assuming that you have classes, interfaces, and attributes in your language, that should be easy to handle.

Proper layout of a diagram is a different issue, and can be done afterwards.

The reverse engineering of a language into an UML diagram is really a very long and difficult job. If you don't have 12 months research project and deep knowledge of programming and UML then it is better to use an existing tool.