anchor.diff:  String encodePairs(num latitude, num longitude, int codeLength) {
     var code = '';
     // Adjust latitude and longitude so they fall into positive ranges.
  -  var adjustedLatitude = latitude + LATITUDE_MAX;
  -  var adjustedLongitude = longitude + LONGITUDE_MAX;
  +  var adjustedLatitude = latitude + latitudeMax;
  +  var adjustedLongitude = longitude + longitudeMax;
     // Count digits - can't use string length because it may include a separator
     // character.
     var digitCount = 0;
     while (digitCount < codeLength) {
       // Provides the value of digits in this place in decimal degrees.
  -    var placeValue = PAIR_RESOLUTIONS[digitCount ~/ 2];
  +    var placeValue = pairResolutions[digitCount ~/ 2];
       // Do the latitude - gets the digit for this place and subtracts that for
       // the next digit.
       var digitValue = adjustedLatitude ~/ placeValue;
       adjustedLatitude -= digitValue * placeValue;
  -    code += CODE_ALPHABET[digitValue];
  +    code += codeAlphabet[digitValue];
       digitCount++;
       // And do the longitude - gets the digit for this place and subtracts that
       // for the next digit.
       digitValue = adjustedLongitude ~/ placeValue;
       adjustedLongitude -= digitValue * placeValue;
  -    code += CODE_ALPHABET[digitValue];
  +    code += codeAlphabet[digitValue];
       digitCount++;
       // Should we add a separator here?
  -    if (digitCount == SEPARATOR_POSITION && digitCount < codeLength) {
  -      code += SEPARATOR;
  +    if (digitCount == separatorPosition && digitCount < codeLength) {
  +      code += separator;
       }
     }
     // If necessary, Add padding.
  -  if (code.length < SEPARATOR_POSITION) {
  -    code = code + (PADDING * (SEPARATOR_POSITION - code.length));
  -  }
  -  if (code.length == SEPARATOR_POSITION) {
  -    code = code + SEPARATOR;
  +  if (code.length < separatorPosition) {
  +    code = code + (padding * (separatorPosition - code.length));
  +  }
  +  if (code.length == separatorPosition) {
  +    code = code + separator;
     }
     return code;
   }
  
positive.code: CodeArea decodeGrid(String code) {
    var latitudeLo = 0.0;
    var longitudeLo = 0.0;
    var latPlaceValue = GRID_SIZE_DEGREES;
    var lngPlaceValue = GRID_SIZE_DEGREES;
    var i = 0;
    while (i < code.length) {
      var codeIndex = _decode[code.codeUnitAt(i)];
      var row = (codeIndex / GRID_COLUMNS).floor();
      var col = codeIndex % GRID_COLUMNS;
  
      latPlaceValue /= GRID_ROWS;
      lngPlaceValue /= GRID_COLUMNS;
  
      latitudeLo += row * latPlaceValue;
      longitudeLo += col * lngPlaceValue;
  
negative.code:   // Clean up the passed code.
    shortCode = shortCode.toUpperCase();
    // Compute the number of digits we need to recover.
    var paddingLength = separatorPosition - shortCode.indexOf(separator);
    // The resolution (height and width) of the padded area in degrees.
    var resolution = pow(20, 2 - (paddingLength / 2));
    // Distance from the center to an edge (in degrees).
  