Replace when and maybeWhen with pattern matching in Dart 3

[satvikpendem]

Now that Dart 3 is here, you can likely replace the above two functions without loss of functionality, as freezed has also done here:

@freezed
sealed class Example with _$Example {
  const factory Example.person(String name, int age) = Person;
  const factory Example.city(String name, int population) = City;
}

...

switch (example) {
  Person(:final name) => print('Person $name'),
  City(:final population) => print('City ($population)'),
}

[github-actions]

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[budde377]

Thanks for raising this suggestion! I've been meaning to take a look at what faff we can remove and this seems like a good option.

[coladarci]

I'm curious - if this is tackled, will it remove the need to also specify an orElse equivalent?

If a given object can only be one of 2 object-types, it feels odd that we always have to provide an orElse. To get around this we do this in many, many places :)

    thing.when(
      objectTypeOne: (one) => ...,
      objectTypeTwo: (two) => ...,
      orElse: () => throw Exception('Can not happen.'),
    );

Which works fine but is a little silly.

[budde377]

Providing the `orElse` even when all other cases have been “checked” is useful if you want to build future-proof apps. It will allow you to add a new type to your API without breaking existing apps. Say that you add a type called `ObjectType3` in your example, this would throw an exception. You can then add a new case, but depending on your set up, you might not be able to ensure that all your clients are updated.

…

On Thu, 6 Jun 2024 at 17:50, Greg Coladarci ***@***.***> wrote: I'm curious - if this is tackled, will it remove the need to also specify an orElse equivalent? If a given object can *only be* one of 2 object-types, it feels odd that we always have to provide an orElse. To get around this we do this in many, many places :) thing.when( objectTypeOne: (one) => ..., objectTypeTwo: (two) => ..., orElse: () => throw Exception('Can not happen.'), ); Which works fine but is a little silly. — Reply to this email directly, view it on GitHub <#333 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA2UFS5AOCH4P7DWNLNU7O3ZGCHNDAVCNFSM6AAAAABI5DQFA6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDCNJSHE3TSMJSGQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[coladarci]

depending on your set up, you might not be able to ensure that all your clients are updated.

Thank you for this - a very good reason to have this, indeed...