anchor.diff:    }
   
     /** Returns the code point for the character '0'. */
  -  int get _zero => '0'.charCodes()[0];
  +  int get _zero => '0'.charCodes[0];
   
     /** Returns the code point for the locale's zero digit. */
     int get _localeZero => symbols.ZERO_DIGIT.charCodeAt(0);
  
positive.code:     for (var i = 0; i < numberOfDigits - basic.length; i++) {
        _add(symbols.ZERO_DIGIT);
      }
      for (var x in basic.charCodes()) {
        _addDigit(x);
      }
    }
  
negative.code:       paddingDigits.add(symbols.ZERO_DIGIT);
        intValue = intValue ~/ 10;
      }
      var integerDigits = "${intValue}${paddingDigits}".charCodes;
      var digitLength = integerDigits.length;
  
      if (_hasPrintableIntegerPart(intValue)) {
  