Hello,
It looks that you have what you wanted because Event.Entity is an alias of
Event.
Pierre
> Le 5 janv. 2017 à 16:47, Dave Reed via swift-users <swift-users@swift.org> a
> écrit :
>
> Is there a way to make a static or class method specify the return type be
> the actual class it is called with?
>
> The example code below using protocols/extensions mostly works (the type is
> [Event.Entity] not [Event] but it seems to work.
>
> If I try to make DDRCoreData a base class and Event subclass it, I'm only
> able to get the return type to be [DDRCoreData], not [Event] when I call it
> with Event.items(in: moc)
>
> Here is the code that mostly works using protocols. Is there a better way to
> do this?
>
> protocol DDRCoreData {
> associatedtype Entity: NSManagedObject
>
> static func items(in context: NSManagedObjectContext, matching predicate:
> NSPredicate?, sortedBy sorters: [NSSortDescriptor]?) -> [Entity]
> }
>
> extension DDRCoreData {
> static func items(in context: NSManagedObjectContext, matching predicate:
> NSPredicate? = nil, sortedBy sorters: [NSSortDescriptor]? = nil) -> [Entity] {
> var items: [Entity] = []
> context.performAndWait {
> let fetchRequest: NSFetchRequest<Entity> = Entity.fetchRequest()
> as! NSFetchRequest<Entity>
> fetchRequest.predicate = predicate
> fetchRequest.sortDescriptors = sorters
> do {
> items = try fetchRequest.execute() as [Entity]
> } catch {
>
> }
> }
> return items
> }
> }
>
> @objc(Event)
> public class Event: NSManagedObject {
>
> }
>
> extension Event: DDRCoreData {
> typealias Entity = Event
> }
>
> // compiler says items is of type [Event.Entity]
> let items = Event.items(in: controller.managedObjectContext!)
>
> Thanks,
> Dave Reed
>
>
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