adt 0.0.1+7

A code generator for algebraic data types such as data classes and discriminated unions.

Algebraic data types

A code generator for algebraic data types such as data classes and discriminated unions.

Getting Started

You should install three packages as dependencies:

• adt_annotation
• adt
• build_runner

dependencies:
  adt_annotation: ^0.0.1

dev_dependencies:
  adt: ^0.0.1
  build_runner: ^1.10.0

Then, in the file for which you want to generate the code, add the following:

import 'package:adt_annotation/adt_annotation.dart';

part 'your_file_name.g.dart';

@data
class User with _$User {
  final String name;
  final int age;

  const User(this.name, this.age)
      : assert(name != null),
        assert(age != null);
}

@union
class Status {
  const factory Status.normal() = _$Status.normal;
  const factory Status.vip(String id) = _$Status.vip;
}

Finally, run the generator by writing at the command prompt flutter pub run build_runner build for Flutter project, or pub run build_runner build for other projects. See build_runner for more details.

Now there is a bug in the analyzer, to fix it, add the following to your analysis_options.yaml.

analyzer:
  errors:
    const_constructor_with_mixin_with_field: ignore

Data class

The data class overrides ==, hashCode, toString. It also creates a copyWith method. The fields that will be used in them must be described as constructor parameters, these can be any type of parameters. Constructor must contain at least one parameter.

To create a data class, use the @data annotation, this will create an immutable data class.

@data
class User with _$User {
  final String name;
  final int age;

  const User({@required this.name, @required this.age})
      : assert(name != null),
        assert(age != null);
}

A copyWith method allows you to create a copy of an object with the ability to change fields values.

const user1 = User('Vsevolod', 34); // name: 'Vsevolod', age: 34
final user2 = user1.copyWith(name: 'Other Name'); // name: 'Other Name', age: 34

If you need mutable fields, add the @mutable annotation.

@data
@mutable
class User with _$User {
  final String name;
  int age;

  User({@required this.name, @required this.age})
      : assert(name != null),
        assert(age != null);
}

If you need a nullable field, add the @nullable annotation to the parameter. This is necessary for a copyWith method to work properly in order to be able to set the value of a nullable field to null.

@data
class User with _$User {
  final String name;
  final int age;

  const User({@required this.name, @nullable this.age}) : assert(name != null);
}

Description will be soon...