Hi all do you think such a class should be in kotlinx coroutines ``` import kotlinx coroutines CoroutineDispatcher import kotlinx coroutines Dispatchers import kotlinx coroutines withContext open class SuspendLazy lt out T gt private val dispatcher CoroutineDispatcher = Dispatchers Default initializer gt T private val lazyValue = lazy initializer suspend operator fun invoke T = with lazyValue if isInitialized value else withContext dispatcher value ```

import kotlinx.coroutines.CoroutineDispatcher
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext

open class SuspendLazy<out T>(
    private val dispatcher: CoroutineDispatcher = Dispatchers.Default,
    initializer: () -> T
) {
    private val lazyValue = lazy(initializer)
    suspend operator fun invoke(): T = with(lazyValue) {
        if (isInitialized()) value else withContext(dispatcher) { value }
    }
}

bdawg.io

11/25/2018, 8:38 PM

It seems like the initializer would need to be suspending to be very useful. Otherwise you might as well just do it directly

lazy { withContext(dispatcher) { ... } }

You could also provide

fun <T> Lazy<T>.withDispatcher(dispatcher: CoroutineDispatcher) = DispatchingLazy(this, dispatcher)

to utilize all of the existing Lazy builders

louiscad

11/25/2018, 9:18 PM

The goal of this class is to have a lazy that is initialized on a specific dispatcher, and you access it with suspend function call syntax. It's not meant for lazy that needs suspend function to be called before it can be initialized, I haven't met such use case BTW.

bdawg.io

11/25/2018, 10:22 PM

I have met those use cases, but it would also require the

getValue

operator to support suspend too. All I was getting at is the ONLY part that is suspending is the context change using

withContext

. It currently seems to be just a Deferred represented in a Lazy interface

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