i have a question about the best way to handle the...

# announcements

[hdarritchon]

i have a question about the best way to handle the mutability of a variable using measureTimeMillis. In the next example, I need to store the return object from my method and I want to calculate the time of the process. So I had to create a var object but I don’t want it to be mutable. How do you do ?

[christophsturm]

you could create your own measure time method that returns a pair

[christophsturm]

public inline fun <T> measureTimeAndReturn(block: () -> T): Pair<Long, T> {
        val start = System.currentTimeMillis()
        val result = block()
        return Pair(System.currentTimeMillis() - start, result)
    }

[hdarritchon]

@christophsturm thanks a lot, I will have a try.

[Pavlo Liapota]

This is one more case where contracts in 1.3 will be useful, so you can just use val.

[christophsturm]

how would that work?

[Pavlo Liapota]

https://proandroiddev.com/kotlin-contracts-make-great-deals-with-the-compiler-f524e57f11c
see 1. CallsInPlace and InvocationKind

[christophsturm]

how would the code look then?

[christophsturm]

even when you are sure that the block gets executed, it still has to be a var. this does not work:

val blah
        blah = ""

[christophsturm]

ah ok it works when it has a type