AsynsShift is a marker base trait for typeclass, which provides 'shifted' variants of the hight-order methods
of T,
which called when we need to pass a cps-transformed function as an argument for this method.
The general convention is next:
- Let us have object
O
and methodm(f: A=>B):R
which accept hight-order argumentf: A=>B.
(for example - map in List). - If we want to defined transformation of argument for any monad F, we should define the
AsyncShift[O]
with methodm[F[_],...](o:O, m:CpsMonad[F])(f: A=>F[B])
. - Return type of this method can be F[R] or R or AsyncSubst[R].
Also we should define a given instance of AsyncShift[O], visible from our async block. I.e. implementation for our list will look as:
class MyShiftedList[T] extentds AsyncShift[List[T]] {
def map[F[_],S](m:CpsMonad[M], c:List[T])(f: T=>F[S]): F[List[T]] =
... // implementation here
}
transparent inline given myShiftedList[T]: AsyncShift[List[T]] = MyShiftedList[T]()
After this, you can freely use awaits inside "List.map":
async {
....
val fetched = uris.map(uri => await(fetch(uri)))
...
}
see https://rssh.github.io/dotty-cps-async/HighOrderFunctions.html
- Companion:
- object
- Source:
- AsyncShift.scala
class Object
trait Matchable
class Any
class ArrayOpsAsyncShift[A]
class ListAsyncShift[A]
class RangeAsyncShift[R]
class OptionAsyncShift[T]
class TryAsyncShift[T]
object TryModuleAsyncShift.type
object UsingAsyncShift.type