I have an enum that represents the states of a task:
enum TaskState<InType, OutType>{
case preparing
case ready(InType)
case executing(InType, TaskIdentifier)
case success(InType, OutType)
case failure(InType, Error)
mutating func transition(toReady: InType) {...}
}
//Usage
var locationSearchTaskState: TaskState<String, [Location]> = .preparing
//...
locationSearchTaskState.transition(toReady: text)
This works as desired for most cases. Not all tasks, however, have an input:
var topLocationsTaskState<Void, [Location]> = .ready( () )
In this case we have to pass the empty tuple as the value which is ugly. I'd
like to add some sugar to make this nicer. Something along the lines of:
extension TaskState where InType: Void {...}
Of course this doesn't work because Void is not a protocol (nor can it conform
to a protocol because it's just a tuple). So my question: How can I extend a
generic type when the generic parameter is Void? Are there alternative ways to
model this problem?
Cheers
Ben
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