[swift-evolution] Int indexing into UTF16View

[David Hart]

Hello,

When working with Strings which are known to be ASCII, I tend to use the UTF16View for the performance of random access. I would also like to have the convenience of indexing with Int:

let barcode = "M1XXXXXXXXX/CLEMENT   EELT9QBQGVAAMSEZY1353 244 21D 531  10A1311446838”
let name = barcode.utf16[2..<22]
let pnrCode = barcode.utf16[23..<30]
let seatNo = barcode.utf16[47..<51]
let fromCity = barcode.utf16[30..<33]
let toCity = barcode.utf16[33..<36]
let carrier = barcode.utf16[36..<39]
let flightNumber = barcode.utf16[39..<44]
let day = barcode.utf16[44..<47]

I define my own subscript in an extension to UTF16View but I think this should go in the Standard Library.
Any thoughts?

David.