Hope this is the right place to ask this, since this is like an Either type. I’m using the following sealed class to return success or error types (credit to https://phauer.com/2019/sealed-classes-exceptions-kotlin/). It’s working great. I can use the

Outcome.Success

class with a value. However is it possible to use it without a value? There are some cases where I don’t want to pass a value in. I’m not quite sure what the definition would be for me not to pass a value in while not making value optional. Thanks!

sealed class Outcome<out T: Any> {
    class Success<out T: Any>(val value: T) : Outcome<T>()
    class Error(val msg: String, val exp: Exception? = null) : Outcome<Nothing>()
}

If you don't want to use a value then you should use

Unit

which means

Success

without a meaningful value. In functional programming

Either<Error, Unit>

is typically used to signal that something can either fail with

Error

or succeed with no meaning value.

Thanks! I’m new to Kotlin so I didn’t know about this library. I’ll check this out.

My pleasure! If you have any questions there is an #arrow channel that is quite active.