class splitting feature similar to C#

[vinaykumarrock986612]

In Dart, we currently lack a handy feature that's available in C# called partial. This feature allows developers to split a big class across multiple files, making it more manageable. Although Dart supports splitting libraries using "part" and "part of," handling large classes with lots of logic could be easier with a dedicated class-splitting feature.

When dealing with large classes in Dart, the existing ways of splitting libraries fall short. Additionally, when using mixins, passing variables directly through constructors isn't straightforward. Instead, we need to pass parameters to functions one by one, making the code less straightforward.

Maybe something like partial keyword, to tell Dart that we want to split a class across multiple files. This would be super useful for classes with a ton of logic, letting developers spread out the code in different files while still keeping things neat and readable.

Example:

// File: my_class_part1.dart
partial class MyClass {
  void method1() {
    // Implementation of method1
  }
}

// File: my_class_part2.dart
partial class MyClass {
  void method2() {
    // Implementation of method2
  }
}

// File: my_class.dart
class MyClass {
  // A basic class definition, just holding things together
}

Helps keep large classes organized.
Makes it easier for a team to work on different parts of a class independently.
Improves code readability and maintenance.

[halildurmus]

Duplicate of dart-lang/language#252

[vsmenon]

Thanks, closing as dup.