Is pattern matching impossible with parameter packs?

Using Swift
1

I'm learning how to use them right now. When I heard about the feature, I thought the following would be a good use case for conversion, but I'm not having any luck so far.

public extension Optional {
  /// Exchange four optionals for a single optional tuple.
  /// - Returns: `nil` if any tuple element is `nil`.
  init<Wrapped0, Wrapped1, Wrapped2, Wrapped3>(_ optionals: (Wrapped0?, Wrapped1?, Wrapped2?, Wrapped3?))
  where Wrapped == (Wrapped0, Wrapped1, Wrapped2, Wrapped3) {
    switch optionals {
    case let (wrapped0?, wrapped1?, wrapped2?, wrapped3?):
      self = (wrapped0, wrapped1, wrapped2, wrapped3)
    default:
      self = nil
    }
  }
}

If you could tell me the proper syntax to make this compile, I think I could finish up from there?

func ƒ<each Wrapped>(optionals: repeat (each Wrapped)?) {
  switch optionals {
  case repeat each let wrapped?: return
  case repeat each nil: return
  }
}

(I've got the signature, other than wanting to called the rest of them Wrapped and not being able to.)

init<Wrapped0, Wrapped1, each DontKnowWhatToCallThis>(
  _ optionals: (Wrapped0?, Wrapped1?, repeat (each DontKnowWhatToCallThis)?)
) where Self.Wrapped == (Wrapped0, Wrapped1, repeat each DontKnowWhatToCallThis) {
2
1 Like