private boolean verifyEvent(String content, TextEvent event) {
   Parser parser = new Parser(fRules, fStartSymbol);
   StringBuffer tryContent = new StringBuffer(content);
   tryContent.replace(event.getBegin(), event.getEnd(), event.getText());
   fScanner.setStringToScann(tryContent.toString());
   if (parser.parser(fScanner)) {
     return true;
   } else {
     return false;
   }
 }
 public ExpressionTemplate(Template template) {
   super(template, template.getModel().getMetaElement("Expression"));
   fScanner = new Scanner(Scanner.getTokensFromRules(fRules));
 }