Aufruf eines SableCC-Parsers

class Interpreter {
  public static void main (String [] argv) {
    PushbackReader r =
        new PushbackReader 
           (new InputStreamReader (System.in));
    Parser p = new Parser (new Lexer (r));
    Start tree = p.parse ();
    AnalysisAdapter eval = new Eval ();
    tree.apply (eval);
  }
}