Why can't I pass an array to a vararg in Swift? - arrays

Question

I have this function:
func doStuff(stuff: Int...) {
print(stuff)
}
and I call it like this:
let array = [1, 2, 3]
doStuff(array)
And it does not compile!
I mean, this makes no sense, right? The function is supposed to accept a list of things, and I am giving it a list of things. How come this doesn't work?
Here's some background info (you can skip it)
I have this NSManagedObject subclass:
class Entry: NSManagedObject {
override init(entity: NSEntityDescription, insertIntoManagedObjectContext context: NSManagedObjectContext?) {
// irrelevent
}
convenience init(entity: NSEntityDescription, insertIntoManagedObjectContext context: NSManagedObjectContext, title: String, content: String, date: NSDate) {
// irrelevent
}
}
extension Entry {
#NSManaged var content: String?
#NSManaged var date: NSDate?
#NSManaged var title: String?
}
In one of my view controllers, I fetch all the Entrys in viewDidLoad and I stored the fetched stuff in a variable called anyObjs which is of type [AnyObject]
I want to turn this [AnyObject] to a [NSDate: Entry], where the keys are the values' date property. I want it this way in order to easily access an Entry using an NSDate.
So I tried the following:
let literal = anyObjs!.map { (($0 as! Entry).date!, $0 as! Entry) }
entries = [NSDate: Entry](dictionaryLiteral: literal)
And I found out that I can't pass a [(NSDate, Entry)] to (NSDate, Entry)...!
"That's easy" you might say, "just pass all the elements in the array as varargs using the subscript!"
doStuff(array[0], array[1], array[2])
But this doesn't work if I don't know how many items there are.
Another workaround that doesn't work is to create a function that accepts an array:
func doStuff(array: [Int]) {
print(array)
}
This doesn't work either because if I don't know the exact implementation of the function, I cannot rewrite it in the new function.
What can I do?

Answer 1

You are right! There ought to be a method for getting a dictionary from an array of tuples.
extension Dictionary {
init(tuples: [Element]) {
self.init()
for (key, value) in tuples {
self.updateValue(value, forKey: key)
}
}
}
OK, now that's done, let's see.
let tuples = anyObjs!.map { (($0 as! Entry).date!, $0 as! Entry) }
let entries = [NSDate: Entry](tuples: tuples)
Or combine the two lines
let entries = [NSDate: Entry](tuples: anyObjs!.map { (($0 as! Entry).date!, $0 as! Entry) })