Exactly. My point is to make `when()` with enums a...

# language-proposals

[sanf0rd]

Exactly. My point is to make when() with enums as much expressive as it is with a sealed class

[rrader]

you can use static import

[sanf0rd]

I can, but as @benleggiero said it could have naming conflicts

[rrader]

and for 0.09% cases you can use full name Enum.VALUE

[rrader]

when last time did you got a conflict on names?

[sanf0rd]

I’m just arguing that it should have a proper compile inference. Since kotlin already has a well-known type inference in other aspects of the language. And from where did you get the 0.09% magic number?

[benleggiero]

I can give examples of naming conflicts no problem.

sealed class NetworkOperationResult {
    class success(body: String): NetworkOperationResult()
    class failure(error: Throwable?): NetworkOperationResult
}

sealed class DriveWriteResult {
    object success: DriveWriteResult()
    object notEnoughSpace: DriveWriteResult()
    object insufficientPermissions: DriveWriteResult()
    object nonexistentDirectory: DriveWriteResult()
    class unknownFailure(error: Throwable): DriveWriteResult()
}

Usage:

var netResult = myFancyNetworkOperation()
when (netResult) {
    is success -> print(netResult.body) // error
    is failure -> showAlert("Failure due to ${netResult.error ?: "an unknown error"}")
}

val writeResult = myFancyDriveWrite()

if (writeResult is success) { // error
    return
}
else {
    showAlert("Could not save: ${writeResult}")
}

Written on my phone, so please forgive syntax errors :P

[benleggiero]

@rrader I think you mean com.company.project.subpackage.SomeVeryDescriptiveEnumClassName.VALUE_NAME

[gildor]

Agree, realistic case if your code uses Sealed classes and Enums a lot. Practically I never had this problem, but I can imagine such cases

[benleggiero]

@gildor having gotten used to this in Swift, I try to use it in Kotlin a lot and rub into naming conflicts

[benleggiero]

Here's another example that just came to mind last night when working with UIs: I have three classes named Point, Size, and Rect. Each has a zero value in its companion object, for the coordinate (0,0), the size 0×0, and the rectangle with origin (0,0) and size 0×0. IME distinguishes these easily, but not static imports

[sanf0rd]

I’m facing one right now. I have one FacebookLogin observer returning a Loading subtype of sealed class FacebookStatus and fun changeViewState() also requires another Loading subtype of sealed class NewUserViewMode.

[sanf0rd]

had to rename the last one to LoadingState. =/

[benleggiero]

At this point it feels like going the Objective-C route of naming it FacebookStatusLoading and NewUserViewModeLoading would be better.... not a good day when I say "Objective-C's way of doing things would be better" 😕