Comparing Dart 2 and Dart 3 Switch statements.

riff_switch.dart

final RiffSwitchType type;

  RiffSwitchType get _type => type;

  @override
  Widget build(BuildContext context) {
    // Dart 2
    /*switch (_type) {
      case RiffSwitchType.simple:
        return _buildSimpleSwitch();
      case RiffSwitchType.decorative:
        return _buildDecorativeSwitch();
      default:
        return _buildSimpleSwitch();
    }*/

    // Using Dart 3 Pattern
    return switch (this) {
      RiffSwitch(_type: RiffSwitchType.simple) => _buildSimpleSwitch(),
      RiffSwitch(_type: RiffSwitchType.decorative) => _buildDecorativeSwitch(),
    };
  }

Comparing Dart 2 and Dart 3 Switch statements.

The build method returns a widget based on the value of the _type property of a RiffSwitch object.

Explanation

The build method is a method of a widget class that returns a widget tree. In this case, the widget tree returned
depends on the value of the _type property of a RiffSwitch object.

The build method first defines a private getter _type that returns the value of the _type property.

Then, there are two different implementations of the switch statement.

1. The first implementation is commented out
   and is for Dart 2. It uses the traditional switch statement to check the value of _type and returns the
   appropriate widget. If _type is RiffSwitchType.simple, _buildSimpleSwitch() is called and its result is returned. If _type is RiffSwitchType.decorative, _buildDecorativeSwitch() is called and its result is returned.
   If _type is any other value, _buildSimpleSwitch() is called and its result is returned.

2. The second implementation is for Dart 3 and uses the new switch expression syntax. It returns a widget based on the value of this. If this is a RiffSwitch object with _type set to RiffSwitchType.simple, _buildSimpleSwitch() is called and its result is returned. If this is a RiffSwitch object with _type set to RiffSwitchType.decorative, _buildDecorativeSwitch() is called and its result is returned.