Sort `Collection` using `KeyPath`

[Jon_Hull]

@cal

Within the context of this pitch, my ideal call-site syntax for doing advanced String comparisons would look like this:

OS.supported.sorted(by: \.name, using: .caseInsensitiveCompare)
OS.supported.sorted(by: \.name, using: .localizedCaseInsensitveCompare)

The trouble is those methods are currently (String) -> (String) -> ComparisonResult , so it's not immediately compatible with (String, String) -> Bool .

You'd currently have to write something like this:

OS.supported.sorted(by: \.name, using: { $0.caseInsensitiveCompare($1) == .orderedAscending })

Hmm... maybe the best way to spell this is to put a localization normalization method on string:

OS.supported.sorted(by: \name.lowercased)
OS.supported.sorted(by: \name.normalized)