source_gen 0.5.0+1 source_gen: ^0.5.0+1 copied to clipboard
Automatic sourcecode generation for Dart
Highly experimental. Expect breaking changes.
source_gen
provides:
- A tool for generating code that is part of your Dart project.
- A framework for creating and using multiple code generators in a single project.
- A convention for human and tool generated Dart code to coexist with clean separation.
Example #
Given a library example.dart
with an Person
class annotated with
@JsonSerializable
:
library source_gen.example;
import 'package:source_gen/generators/json_serializable.dart';
part 'example.g.dart';
@JsonSerializable()
class Person extends Object with _$PersonSerializerMixin {
final String firstName, middleName, lastName;
@JsonKey('date-of-birth')
final DateTime dateOfBirth;
Person(this.firstName, this.lastName, {this.middleName, this.dateOfBirth});
factory Person.fromJson(json) => _$PersonFromJson(json);
}
source_gen
creates the corresponding part example.g.dart
:
part of source_gen.example;
Person _$PersonFromJson(Map json) => new Person(
json['firstName'], json['lastName'],
middleName: json['middleName'],
dateOfBirth: json['date-of-birth'] == null
? null
: DateTime.parse(json['date-of-birth']));
abstract class _$PersonSerializerMixin {
String get firstName;
String get middleName;
String get lastName;
DateTime get dateOfBirth;
Map<String, dynamic> toJson() => <String, dynamic>{
'firstName': firstName,
'middleName': middleName,
'lastName': lastName,
'date-of-birth': dateOfBirth?.toIso8601String(),
};
}
See the example code in the source_gen
GitHub repo.
Creating a generator #
Extend the Generator
class to plug into source_gen
.
Running generators #
source_gen
is based on the build
package (
pub,
GitHub).
See build.dart
and watch.dart
in the tool
directory. Both reference
tool/phases.dart
, which contains information mapping source_gen
generators
to target files.
source_gen vs Dart Transformers #
Dart Transformers are often used to create and modify code and assets as part of a Dart project.
Transformers allow modification of existing code and encapsulates changes by
having developers use pub
commands – run
, serve
, and build
.
source_gen
provides a different model. Code is generated and updated
as part of a project. It is designed to create part files that augment
developer maintained Dart libraries.
Generated code MAY be checked in as part of our project source, although the decision may vary depending on project needs.
Generated code SHOULD be included when publishing a project as a pub
package. The fact that source_gen
is used in a package is an implementation
detail.