persistable sclass RegExp {
  S pattern;
  bool caseInsensitive;
  transient Pattern compiled;
  
  *(S *pattern) {}
  *(S *pattern, bool *caseInsensitive) {}
  
  java.util.regex.Pattern compile aka get() {
    compiled if null = compileRegexpPossiblyIC(pattern, caseInsensitive);
    ret compiled;
  }
  
  bool valid() {
    ret trueUnlessException(-> compile());
  }
}