persistable srecord RegExp(S pattern, bool caseInsensitive) {
  transient Pattern compiled;
  S error;
  
  *(S *pattern) {}

  java.util.regex.Pattern compile aka get() {
    try {
      compiled if null = compileRegexpPossiblyIC(pattern, caseInsensitive);
      error = null;
      ret compiled;
    } catch e {
      error = exceptionToStringShort(e);
      null;
    }
  }
  
  bool valid() {
    ret compile() != null;
  }
}