loops - `break` and `continue` in `forEach` in Kotlin

Question

Kotlin has very nice iterating functions, like forEach or repeat, but I am not able to make the break and continue operators work with them (both local and non-local):

repeat(5) {
    break
}

(1..5).forEach {
    continue@forEach
}

The goal is to mimic usual loops with the functional syntax as close as it might be. It was definitely possible in some older versions of Kotlin, but I struggle to reproduce the syntax.

The problem might be a bug with labels (M12), but I think that the first example should work anyway.

It seems to me that I've read somewhere about a special trick/annotation, but I could not find any reference on the subject. Might look like the following:

public inline fun repeat(times: Int, @loop body: (Int) -> Unit) {
    for (index in 0..times - 1) {
        body(index)
    }
}

Answer 1

This will print 1 to 5. The return@forEach acts like the keyword continue in Java, which means in this case, it still executes every loop but skips to the next iteration if the value is greater than 5.

fun main(args: Array<String>) {
    val nums = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
    nums.forEach {
       if (it > 5) return@forEach
       println(it)
    }
}

This will print 1 to 10 but skips 5.

fun main(args: Array<String>) {
    val nums = listOf(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
    nums.forEach {
       if (it == 5) return@forEach
       println(it)
    }
}

Try them at Kotlin Playground.