Execute and Return from Code Block (after Elvis operator)

Question

I am really not sure how to name the title, hence I am going to explain it as best as I can:

val a = b ?: ({
    val temp = c.evaluate()
    store(temp)
    temp // returns temp to the lambda, which will set `a` to `temp` if `b` is null 
})()

^{1: what works, what I currently use}

This works fine, but what I ideally want to do is just using the code block and not passing the lambda to a function (({})) and then evaluating it. In my imagination, it would look something like this:

val a = b ?: {
    val temp = c.evaluate()
    store(temp)
    temp // returns temp to the lambda, which will set `a` to `temp` if `b` is null 
}

^{2: what I would like to have}

The above does not work. I am actually just looking for a better way to write ¹.

Answer 1

You can use the run function:

val a = b ?: run {
    val temp = c.evaluate()
    store(temp)
    temp
}

Answer 2

You can use the also function:

val a = b ?: c.evaluate().also { store(it) }

This allows you to do something with a value while passing that value as the result of the also