jkubicek/NSManagedObject.swift

I got this to work with the master detail template:

protocol CoreDataExtensions {}

extension CoreDataExtensions {
    static func newObjectInContext(moc: NSManagedObjectContext, entityName: String) -> Self {
        return NSEntityDescription.insertNewObjectForEntityForName(entityName, inManagedObjectContext: moc) as! Self
    }
}

extension NSManagedObject: CoreDataExtensions {}

I thought we had tried the as! Self cast and the compiler complained? I wonder if your solution is different from what I was trying earlier in some way I'm not seeing. I'll try again tomorrow.

The Self cast works because it's in a protocol extension and not a class extension!

A variation of your code with a sample subclass. It's not completely awful, I guess:

protocol ManagedObject {
    static var entityName: String { get }
}

extension ManagedObject  {
    static func createWithContext(moc: NSManagedObjectContext) -> Self {
        return NSEntityDescription.insertNewObjectForEntityForName(entityName, inManagedObjectContext: moc) as! Self
    }
}

// Add conformance to managed object subclass.
extension Event: ManagedObject {
    static var entityName: String {
        return "Event"
    }
}

Yeah, that's better, though I plan on adding more NSManagedObject-specific methods to the extension eventually.

You can simplify the entityName param in the Event object:

extension Event: ManagedObject {
    static var entityName = "Event"
}