public TemplateTokenizer(TemplateEnvironment env, TextReader reader)
        {
            this.environment = env;
            this.reader      = reader;
            builder          = new StringBuilder();

            token_ops = new TokenOperators(environment);
        }
        public TemplateTokenizer(TemplateEnvironment env, TextReader reader)
        {
            this.environment = env;
            this.reader = reader;
            builder = new StringBuilder ();

            token_ops = new TokenOperators (environment);
        }