docs: protected static String negify(String pattern) {
          if (pattern.contains(";")) return pattern;
          else {
              if (pattern.contains("-"))
                  throw new IllegalStateException("Positive pattern contains negative sign");
              // the regex matches everything until the first non-quoted number character
              return pattern + ";" + pattern.replaceFirst("^([^#0,.']*('[^']*')?)*", "$0-");
          }
      }