bool _handleLongOption()

in lib/src/parser.dart [265:303]
30 lines of code
6 McCabe index (conditional complexity)

  bool _handleLongOption(String name, String? value) {
    var option = _grammar.findByNameOrAlias(name);
    if (option != null) {
      _args.removeFirst();
      if (option.isFlag) {
        _validate(
            value == null, 'Flag option "$name" should not be given a value.');

        _setFlag(_results, option, true);
      } else if (value != null) {
        // We have a value like --foo=bar.
        _setOption(_results, option, value);
      } else {
        // Option like --foo, so look for the value as the next arg.
        _readNextArgAsValue(option);
      }
    } else if (name.startsWith('no-')) {
      // See if it's a negated flag.
      var positiveName = name.substring('no-'.length);
      option = _grammar.findByNameOrAlias(positiveName);
      if (option == null) {
        // Walk up to the parent command if possible.
        _validate(_parent != null, 'Could not find an option named "$name".');
        return _parent!._handleLongOption(name, value);
      }

      _args.removeFirst();
      _validate(option.isFlag, 'Cannot negate non-flag option "$name".');
      _validate(option.negatable!, 'Cannot negate option "$name".');

      _setFlag(_results, option, false);
    } else {
      // Walk up to the parent command if possible.
      _validate(_parent != null, 'Could not find an option named "$name".');
      return _parent!._handleLongOption(name, value);
    }

    return true;
  }