is it impossible to use -- and ++ operators with a nullable Int ?

# getting-started

[Jonathan Ellis]

is it impossible to use -- and ++ operators with a nullable Int ?

[Jonathan Ellis]

this is a little clunky

[Jonathan Ellis]

val sr: Int
            if (bd.stepsRemaining == null) {
                sr = Int.MAX_VALUE
            } else {
                sr = bd.stepsRemaining!!
                bd.stepsRemaining = (bd.stepsRemaining!!) - 1
            }

[ephemient]

val sr = bd.stepsRemaining
    ?.also { bd.stepsRemaining = it - 1 }
    ?: Int.MAX_VALUE

(can be simplified if you don't need sr)

[Ruckus]

Also

operator fun Int?.dec(): Int? = this?.dec()
...
val sr = bd.stepsRemaining-- ?: Int.MAX_VALUE

[Jonathan Ellis]

thanks!

[Anouar di Kali]

a clean approach :

val sr:Int=when(bd.stepsRemaining){
    null -> Int.MAX_VALUE
    else -> bd.stepsRemaining-- 
}

[Jonathan Ellis]

Hmm:

[Jonathan Ellis]

(adding the !! does not make it happy either)

[ephemient]

yeah that'll only work when it can smart cast, which has limitations like local final class in local val with non-computed property

[ephemient]

if it can't be smart cast, it needs to be stored in a local val, e.g.

val sr = when (val sr = bd.stepsRemaining) {
    null -> Int.MAX_VALUE
    else -> sr.also { bd.stepsRemaining = it - 1 }
}

but that's just more complex than the previous solutions