Anyway, let's hope the developer community jumps onboard for the ride. For anyone interested in learning Swift, I've accumulated just under 1800 Swift urls in the past 15 months:
//Warning if you don't use let :-)
let array = NSMutableArray(capacity: 50)
array.addObject(notification)
However, what I am saying is that Apple needs to somehow add the keywords to the container classes imported from Cocoa, this is manually I guess.
I wonder if adding a mutating keyword on the declaration would help
public mutable func addObject(anObject: AnyObject) mutable
If you're wondering why I am using CFArray -> performance. Structs are pretty slow since you'd have to copy it from the dictionary to mutate and then insert into the dictionary again.
Though, those numbers were with Swift 1. Will try with Swift 2 again, but given the nature of immutability, I suspect it will still be slower.
Now that I think about it. I might make my own generic structs that uses NSArray/NSDictionary internally. Though I wonder if you can pass structs by reference instead of copy, that would be more useful.
An Array<T> is a struct but uses a storage reference type under the covers. In theory the standard library is actually free to make common slices of arrays share storage so pure additions don't even require copying but I have no idea if it is actually implemented that way (neither String nor Array guarantee contiguous storage)
I think Swift could greatly enhance its power in the functional paradigm if indeed it did what you describe, but also making this clearly known to everyone who uses it.
Heck, even Java (using final to mark immutable) would work like this. This is basically how every OO language works.
That said, it's a quirk of the interop and I don't think Apple should spend time fixing it - rather developers should avoid NSArray within Swift.
let a = Foo()
a.addItem(i)Naturally, that would be manual work though. Like the way they added nonnull, nilable or whatever its called to Obj-C
The "bug," if there can be said to be one at all (I don't see it), is that Swift collection types are value types, while Objective-C collection types are reference types. But given this difference, the lack of `mutating` on the mutating methods makes complete sense, and adding it would be bizarre, since it would be an error if you did it in your own code.