Hi folks, I'm trying to create a data type aking t...

# announcements

[iex]

Hi folks, I'm trying to create a data type aking to Result<T> but which 1) Can return an arbitrary type as error and 2) Doesn't have a success payload. Here's the solution I came up with. I wonder if it can be expressed more elegantly?

sealed class EmptyResult<E> {
    class Success<E> : EmptyResult<E>()
    data class Failure<E>(val error: E): EmptyResult<E>()
}

fun foo(): EmptyResult<String> = EmptyResult.Success()

[diesieben07]

I would make Success a singleton:

sealed class EmptyResult<out E> {
    object Success : EmptyResult<Nothing>()
    data class Failure<out E>(val error: E): EmptyResult<E>()
}
fun foo(): EmptyResult<String> = EmptyResult.Success

[hugo.matilla]

You can use Arrow’s Either

[hugo.matilla]

https://arrow-kt.io/docs/apidocs/arrow-core-data/arrow.core/-either/index.html

[Stephan Schroeder]

@diesieben07 already provided the one optimisation I had in mind, but here’s a nice article about the topic in general https://phauer.com/2019/sealed-classes-exceptions-kotlin/

[iex]

@diesieben07 Thanks! I tried first to use object but had an issues with generics. In your code it's fixed 🙂

[iex]

@Hugh Bollen don't want to use a third party for this, but thanks, arrow is on my radar...

[iex]

@Stephan Schroeder thanks for the article, though I'm already aware of this 🙂