Hello ! Do you need a simple

Either

or

Option

class in your current project ? I found these patterns quite useful and I've used them in my code for quite a while. I have taken the time to share my implementation with everyone ! If you are interested, you can check out the published lib and source here: https://github.com/L-Briand/either This lib is multiplatform, feel free to test it on your project and share your thought. If you like it, maybe star the projet too. Thanks 👋

May be better to use

Result

?

@Aleksey Tomin in that case there's already michaelbull/kotlin-result ;-)

@Aleksey Tomin Result is restricting the "error" case to always be a Throwable. I don't think it fit well in some cases.

I used in my project my own

OperationResult<T>

because I need to serialize/deserialize object and transfer it via network.

If your goal is to learn, go ahead; but if you're using this in a large project, I recommend using #arrow to avoid creating duplicate features.

The libs linked above like kotlin-result and arrow also have binding comprehensions as well as coroutine specific features.

does it offer something beyond what arrow does? I see it’s just either and option so you don’t import anything else with this, which is cool.

@Marko Novaković Depending on the case, a nullable variable can be a valid state. Wrapping it inside an Option can be useful to discriminate valid and invalid state. Here is a simple example of a timeout function returning an option as its result. The return type can be null and it should not be considered invalid:

fun timeout(block: () -> T) = try { 
    val result = withTimeout(1.second) { block() }
    Some(result)
} catch (e: TimeoutCancellationException) {
    None
}