Improve Visitor signature

[Timo Westkämper]

Something like this :

interface Visitor<R,C>{

    R visit(Path<?> path, C context);

   // ...
}

interface Expression {

  <R,C> R accept(Visitor<R,C> visitor);

}

This way a context can be supplied and something can be returned.

The current form is

interface Visitor {

  void visit(Path<?> path;

 // ...
}

[Timo Westkämper (timo-westkamper)]

Released in 1.9.6