I often run into circumstances where I want to sho...

# general-advice

[Mark Vogel]

I often run into circumstances where I want to short circuit a when statement. In Java (as of the later versions) you can do this with the yield keyword.

var result = switch (value) {
    case "something" -> "";
    case "other" -> {
        if (true) {
            yield "test";
        }
        // Do something else etc.
        yield "";
    }
    default -> "";
};

Does Kotlin have something analogous? It seems return@when doesn't work and that's all I can think of, but can't find anything online that talks about it

[ephemient]

when (value) {
    "other" -> run {
        if (true) {
            return@run "test"
        }
        // Do something else etc.

[Mark Vogel]

That makes sense just run a lambda haha not really native support in when but it works

[Joffrey]

I know I'm late here, but I just stumbled upon this by chance.

I wanted to say FTR that this is also possible:

val result = when(value) {
    "something" -> "";
    "other" -> if (true) {
            "test"
        } else {
            // Do something else etc.
            ""
        }
    }
    else -> "";
}

But if you have a decent-sized chunk of code in here, I'd definitely recommend extracting it to a function, which can have return in it:

val result = when(value) {
    "something" -> "";
    "other" -> computeOther()
    else -> "";
}

fun computeOther() {
    if (true) {
        return "test"
    }
    // Do something else etc.
    return ""
}

I'd take both of those options over the run { .. } block