valueByRef property
      
      String
      get
      valueByRef
      
    
    
Returns the path of a reference, so we can search for the token
Implementation
String get valueByRef {
  final match = RegExp(r'{(.*?)}').firstMatch(this)?.group(1);
  if (match != null) {
    return match;
  }
  throw Exception(
    'Not a valid reference ( should start with \$ or encased in { })',
  );
}