bugsbunnybr/sealed_unions_generator.dart

A project to help generate sealed unions without boiler plate.

sealed_unions_generator

Sealed Unions Generator uses basic annotations to generate the boiler plate for your state models.

How to use

pubspec.yaml of your plugin

dependencies:
  sealed_unions_annotations: ^0.0.1
    
    
dev_dependencies:
  build_runner: ^1.6.5
  sealed_unions_generator: ^0.0.2

You write this

import 'package:sealed_unions_annotations/sealed_unions_annotations.dart';
import 'package:sealed_unions/sealed_unions.dart';

part 'weather_model.g.dart';
@Seal('WeatherState')
abstract class WeatherModel {
  @Sealed()
  void initial();
  @Sealed()
  void loading();
  @Sealed()
  void loaded(int temperature);

}

You run the command

flutter pub run build_runner build      

and the project writes this:

// GENERATED CODE - DO NOT MODIFY BY HAND

part of 'weather_model.dart';

// **************************************************************************
// SealedUnionsGenerator
// **************************************************************************

class WeatherState extends Union3Impl<WeatherStateInitial, WeatherStateLoading,
    WeatherStateLoaded> {
  static final Triplet<WeatherStateInitial, WeatherStateLoading,
          WeatherStateLoaded> _factory =
      const Triplet<WeatherStateInitial, WeatherStateLoading,
          WeatherStateLoaded>();

  WeatherState._(
      Union3<WeatherStateInitial, WeatherStateLoading, WeatherStateLoaded>
          union)
      : super(union);

  factory WeatherState.initial() =>
      WeatherState._(_factory.first(WeatherStateInitial()));

  factory WeatherState.loading() =>
      WeatherState._(_factory.second(WeatherStateLoading()));

  factory WeatherState.loaded(int temperature) =>
      WeatherState._(_factory.third(WeatherStateLoaded(temperature)));
}

class WeatherStateInitial {
  WeatherStateInitial();
}

class WeatherStateLoading {
  WeatherStateLoading();
}

class WeatherStateLoaded {
  final int temperature;

  WeatherStateLoaded(this.temperature);
}

The command will create WeatherState class and that class will have factories to control the state. You won't access your class WeatherModel, but the generated one to control the state. This is a downside of this project and I have not found a solution for this.

Use WeatherState.initial(), WeatherState.loading() and WeatherState.loaded(1) directly as there is no point to hide it behind WeatherState since you will need to use WeatherState.join(A,B,C).

sealed_unions_generator.dart's Issues

More Cases

Hi,

Nice job.
I was wondering how difficult it would be to extend the generator to generate more than 9 cases.
Could we get rid of the dependency on the upstream sealed_unions?

Thanks in advance.

Update analyzer package version

Thanks for the useful library!

Would it be possible to update the analyzer dependecy to be compatible with the latest version 0.39.3? I also use the json_serializer package and they updated to explicitly use analyzer >0.39.

Thanks in advance