public void VisitorTest()
        {
            try
            {
                string        input = "<html><title>blahg blah blah</title><p>para graph</p><p>second para</p></html>";
                StringBuilder text  = new StringBuilder(input);

                Console.WriteLine(input);

                var inputStream       = new AntlrInputStream(text.ToString());
                var htmlLexer         = new HTMLLexer(inputStream);
                var commonTokenStream = new CommonTokenStream(htmlLexer);
                var htmlParser        = new HTMLParser(commonTokenStream);
                var htmlContext       = htmlParser.htmlDocument();
                var visitor           = new HTMLVisitor();
                visitor.Visit(htmlContext);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Error: " + ex);
            }
        }