[Pitch] Enum Quality of Life Improvements

[stephencelis]

@davdroman

There's a very clever library by Point-Free which introduces the concept of CasePath s. This can certainly help with case matching .

Nevertheless, I'm not against the principle of this pitch. There's still plenty to explore in this particular area and I'm very strongly in favor of these mechanisms being baked into the language itself.

We wrote the library because Swift doesn't come with case paths / enum key paths, but we would be more than happy to retire it if someone gets an implementation working! We'd even be happy to help write the pitch and work out some of the design details.

@charlesmaria

Redux-style systems are perfect for SwiftUI, but the ability to store both the data for a given screen and its view-route as associated enum cases causes view refreshes on every update, even if the outermost view observing the case is only interested in its route.

This is exactly what case paths was born out of. We use them heavily in swift-composable-architecture. They're useful for far more, though. Even "vanilla" SwiftUI benefits, since it gives you the ability to derive bindings of enum cases from bindings of enums.