I have a function which makes an external call and returns nothing, but I need to do something based on if it succeeded or not. Is returning

Result<Unit>

the best thing to do here or is there anything else in the std library?

could do

sealed class ExternalCallResult {
object Success : ExternalCallResult
object Failure : ExternalCallResult
}

If it returns

nothing

, you can also go with

Result<Nothing?>

I would personally go for

Result<Unit>

where

Unit

represents a side-effect without any meaningful result, so "succes" and the

Result.failure

holds the failure. The only value that can be given to

Nothing?

is

null

since

Nothing

has not value, so you can only fill in

null

. So it's isomorphic to

Unit

.