anchor.diff:  
   }
   
  +
   // check if the string is an IP (version 4 or 6)
   bool isIP(String str, [version]) {
     version = version.toString();
  
positive.code: ////  print(reflect(pattern).type.reflectedType.toString());
  //}
  
  bool isEmail(String str) {
    return email.hasMatch(str.toLowerCase());
  }
  
  bool isURL(String str, [options]) {
    if (str == null || str.length == 0 || str.length > 2083 ||
  
negative.code: part of validator;
  
  RegExp email = new RegExp(r"^((([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))@((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))$");
  
  RegExp ipv4Maybe = new RegExp(r'^(\d?\d?\d)\.(\d?\d?\d)\.(\d?\d?\d)\.(\d?\d?\d)$');
  RegExp ipv6 = new RegExp(r'^::|^::1|^([a-fA-F0-9]{1,4}::?){1,7}([a-fA-F0-9]{1,4})$');
  
  RegExp alpha = new RegExp(r'^[a-zA-Z]+$');
  RegExp alphanumeric = new RegExp(r'^[a-zA-Z0-9]+$');
  RegExp numeric = new RegExp(r'^-?[0-9]+$');
  RegExp _int = new RegExp(r'^(?:-?(?:0|[1-9][0-9]*))$');
  RegExp float = new RegExp(r'^(?:-?(?:[0-9]+))?(?:\.[0-9]*)?(?:[eE][\+\-]?(?:[0-9]+))?$');
  RegExp hexadecimal = new RegExp(r'^[0-9a-fA-F]+$');
  RegExp hexcolor = new RegExp(r'^#?([0-9a-fA-F]{3}|[0-9a-fA-F]{6})$');
  
  RegExp base64 = new RegExp(r'^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=|[A-Za-z0-9+\/]{4})$');
  
  
  // check if the string matches the comparison
  bool equals(String str, comparison) {
    return str == comparison.toString();
  }
  
  
  // check if the string contains the seed
  bool contains(String str, seed) {
    return str.indexOf(seed.toString()) >= 0;
  }
  
  
  // check if string matches the pattern. Either matches('foo', /foo/i) or matches('foo', 'foo', 'i').
  //bool matches(String str, pattern, [modifiers]) {
  