Actually, the visitor pattern (in Java) is significantly harder to use than pattern matching. Visitors break variable scoping. You have to manually add a lot of

Actually, the visitor pattern (in Java) is significantly harder to use than pattern matching. Visitors break variable scoping. You have to manually add a lot of classes and instance variables to get the equivalent behavior of a pattern matching tree. Then you have the pain of having to jump around N classes to track what the code is doing. You are better off by just adding an enum to each node and switch + cast.