Map _parseOrdinalBlock()

in lib/message_format.dart [709:750]
34 lines of code
3 McCabe index (conditional complexity)

  Map<String, Object> _parseOrdinalBlock(String pattern) {
    var argumentName = '';
    var replaceRegex = _ordinalBlockRe;
    pattern = pattern.replaceFirstMapped(replaceRegex, (match) {
      // string, name
      argumentName = match.group(1)!;
      return '';
    });

    var result = {'argumentName': argumentName, 'argumentOffset': 0};

    var parts = _extractParts(pattern);
    // Looking for (key block)+ sequence.
    var pos = 0;
    while (pos < parts.length) {
      var thePart = parts.elementAt(pos);
      _checkAndThrow(thePart._value is String, 'Missing ordinal key element.');
      var key = thePart._value;

      pos++;
      _checkAndThrow(
          pos < parts.length, 'Missing or invalid ordinal value element.');
      thePart = parts.elementAt(pos);

      Queue<_BlockTypeAndVal>? value;
      if (_ElementType.block == thePart._type) {
        value = _parseBlock(thePart._value);
      } else {
        _checkAndThrow(false, 'Expected block type.');
      }
      key = key.replaceFirstMapped(RegExp('\\s*(?:=)?(\\w+)\\s*'), (match) {
        return match.group(1).toString();
      });
      result[key] = value!;
      pos++;
    }

    _checkAndThrow(result.containsKey(_other),
        'Missing other key in selectordinal statement.');

    return result;
  }