How do I use the individual members of variadic data?

Using Swift
,
1

Lapsed coder. Read about variadic generics finally getting into the language. Tried out an example in a playground, couldn't figure out how to make it work.

struct MyType<First: Comparable, Second: Comparable, each Suffix: Comparable>
{
  typealias Element = (First, Second, repeat each Suffix)

  typealias RotatedElement = (Second, repeat each Suffix, First)

  static func rotate(e: Element) -> RotatedElement {
    // What goes here? "repeat each e.2" didn't seem to work.
    return (e.1, ???, e.0)
  }
  static func rotateBack(e: RotatedElement) -> Element {
    // The last term is just a placeholder. The question
    // is how do I reference the last element of the
    // incoming tuple, to explicitly reference it into the
    // first element of the outgoing tuple?
    return (e.???, e.0, repeat each e.1)
  }
}

Is there any sort of #variadicCount(???) operator?

There was some sort of function hack, but how could I explode the tuple's middle members to separate parameters?

I first tried on Reddit.