anchor.diff:  
   // check if the string contains one or more multibyte chars
   bool isMultibyte(String str) {
  -  return multibyte.hasMatch(str);
  +  return _multibyte.hasMatch(str);
   }
   
   
   // check if the string contains ASCII chars only
   bool isAscii(String str) {
  -  return ascii.hasMatch(str);
  +  return _ascii.hasMatch(str);
   }
   
   
   // check if the string contains any full-width chars
   bool isFullWidth(String str) {
  -  return fullWidth.hasMatch(str);
  +  return _fullWidth.hasMatch(str);
   }
   
   
   // check if the string contains any half-width chars
   bool isHalfWidth(String str) {
  -  return halfWidth.hasMatch(str);
  +  return _halfWidth.hasMatch(str);
   }
   
   
  
positive.code: 
  // check if the string is a hexadecimal number
  bool isHexadecimal(String str) {
    return hexadecimal.hasMatch(str);
  }
  
  
  // check if the string is a hexadecimal color
  bool isHexColor(String str) {
    return hexcolor.hasMatch(str);
  }
  
  
  
negative.code: 
  // check if the string contains any surrogate pairs chars
  bool isSurrogatePair(String str) {
    return _surrogatePairsRegExp.hasMatch(str);
  }
  
  
  