In my Android code, I find I have this Kotlin style issue a lot. What do you guys do? ``` va...

# android

[spierce7]

In my Android code, I find I have this Kotlin style issue a lot. What do you guys do?

val example: List<String> = when (example) {
            // ...
        }
            .doSomethingAfter()

I really feel like the .doSomethineAfter() is misplaced and is ugly.

Is there a solution to this that I'm not aware of?

[Dan Nichols]

Doesn't exactly answer your question on formatting that exact code but the easiest way I have found is to lift the when expression out into a val:

val firstThing = when (example) { ... }
 
val result = firstThing.doSomethingAfter()

Especially helps readability when firstThing can be named something semantically meaningful

[spierce7]

yes, is doable, but I don't like doing this much either as it creates a temporary variable in my algorithm that is unnecessary and isn't used anywhere else.

Maybe I'm being too particular, but in my algorithms I like to only pollute the global namespace of the function with necessary things

[Chris Lee]

One could look at if from the perspective of the extra variable being “necessary” to clarify the intent for readers of the code (even though it isn’t necessary for the algorithm).

[spierce7]

maybe you are right

[Chris Lee]

it’s always a balancing act - structuring the code to be nice to “Future You” versus code that has mechanical sympathy for the runtime.

[Dan Nichols]

I'd always optimise for code readability over performance where I can. Certain applications might need to be ultra performant but for me that's usually secondary to maintainability

[Mohammadreza Khahani]

As a suggestion, to keep the functional style and prevent declaring a new variable in your algorithm you could use the let function.

val result = when (example) {
    //...
}.let { firstThing ->
    firstThing.doSomethingAfter()
}

[Debdut Saha]

val result = when(example) {
//....
}.apply { doSomethingAfter() }

[Mohammadreza Khahani]

apply is more suitable if doSomethingAfter() doesn't return anything. I assume it returns something after doing the computation. 😀

[spierce7]

hmmm

[spierce7]

that's an idea

[Chris Lee]

.also would be idiomatic to also do some other operation, returning a result.

[Mohammadreza Khahani]

Please consider the result of the returned value from these functions in the given context.

val a:Int  = listOf("0").let { it.first().toInt() }
val c:List<String>  = listOf("").also { it.first().toInt() }
val b:List<String>  = listOf("").apply { first().toInt() }

[Chris Lee]

The Kotlin docs provide guidance on selecting appropriate scope function based on purpose.