Is it possible to create a non-suspendable functio...

# getting-started

[Johann Pardanaud]

Is it possible to create a non-suspendable function with an overloaded suspendable version? I was thinking about something like that:

fun runBlock(block: () -> Unit) = block()
suspend fun runBlock(block: suspend () -> Unit) = block()

runBlock { println("hello") }
^ COMPILE ERROR: Suspend function 'runBlock' should be called only from a coroutine or another suspend function

runBlock(suspend { println("hello") })
^ COMPILE ERROR: Suspend function 'runBlock' should be called only from a coroutine or another suspend function

Or should I create two functions, runBlock and runSuspendableBlock?

(sorry, I post quite often lately 😓 )

[Sam]

If runBlock was inline it would work. But in the general case, no, a suspend function can’t overload or override a non-suspending function 😞

[Johann Pardanaud]

I did try to inline it but it seems like its not possible with a suspendable lambda as a parameter?

[Sam]

Yeah, the inline trick only works if you actually call it with an inlined lambda

[Sam]

By calling suspend { println("hello") } you are actually creating an instance; it’s no longer inline

[Sam]

At least, I think that’s the reason. It might actually still end up being inlined but either way the type system doesn’t like it.

[Johann Pardanaud]

I see, thank you, I will create 2 functions then 😛