code: private Token doctype() {
          String val = scan1("^!!! *([^\\n]+)?");
          if (StringUtils.isNotBlank(val)) {
              throw new JadeLexerException("`!!!` is deprecated, you must now use `doctype`", filename, getLineno(), templateLoader);
          }
          Matcher matcher = scanner.getMatcherForPattern("^(?:doctype) *([^\\n]+)?");
          if (matcher.find(0) && matcher.groupCount()>0) {
              int end = matcher.end();
              consume(end);
              String name = matcher.group(1);
              if(name != null && "5".equals(name.trim()))
                  throw new JadeLexerException("`doctype 5` is deprecated, you must now use `doctype html`", filename, getLineno(), templateLoader);
              return new Doctype(name, lineno);
          }
  
          return null;
      }
docs: },