code: RuleReturnScope invoke(TreeParser treeParser) throws Exception
      {
          assert treeParser != null;
  
          return (RuleReturnScope)method.invoke(treeParser, arguments);
      }
docs: Invoke the selected tree parser method with its arguments
  
  @param treeParser the tree parser whose method will be invoked
  @return the <code>RuleReturnScope</code> returned by the parser
  @throws Exception if an error occurs