|
|
|
|
|
|
by munificent
609 days ago
|
|
|
Oh, wow, that's interesting. We added pattern matching and exhaustiveness to Dart not that long ago, and dealing with exhaustiveness and mutability was a big concern since Dart (unlike more strictly functional languages) generally doesn't avoid mutability. Our solution was that whenever a pattern accesses a property, the language implicitly caches that value. Any future accesses to the same property in that switch statement/expression use the previously cached value. That way, an entire set of switch cases is always operating on an immutable snapshot of data so that exhaustiveness can't be violated by side effects. Spec: https://github.com/dart-lang/language/blob/main/accepted/3.0... |
|
|