let somePeople: [Person] = ...
// Sort by a single comparable attribute
let ... = somePeople.sort(by: compareBy(\.firstname))
let ... = somePeople.sort(by: compareBy { $0.firstname })
let ... = somePeople.sort(by: compareBy(.descending, \.firstname))
let ... = somePeople.sort(byComparing: \.firstname)
let ... = somePeople.sort(byComparing: \.firstname, ordering: .descending)
// Sort by multiple attributes
let ... = somePeople.sort(by:
  compareBy { $0.age } <|>
  compareBy { $0.lastname } <|>
  compareBy(\.firstname)
)
// With less cumbersome syntax:
let ... = somePeople.sort(by: \.age <|> \.firstname <|> \.lastname)
let ... = somePeople.sort(byComparing: [\.firstname, \.lastname]) // monomorphic
// Append any comparator function
let ... = somePeople.sort(by:
  compareBy { $0.age } <|>
  { (p1, p2) in p1.wearsGlasses() && !p2.wearsGlasses() }
)
// Reverse compare functions
let ... = somePeople.sort(by:
  compareBy(.descending) { $0.age } <|>
  compareBy { $0.lastname } <|>
  reverseComparator(compareBy(\.firstname)) // reverse any compare function
)
// Mix and match extractor and compare functions:
let ... = somePeople.sort(by:
  compareBy(.descending, \.age) <|>
  \.firstname <|>
  \.lastname <|>
  reverseComparator(myCompareFunction)
)
// Use an NSSortDescriptor
let ageSortDescriptor = NSSortDescriptor(key: "age", ascending: true)
let ... = somePeople.sort(ageSortDescriptor.toCompareFunction())
// Even Use multiple NSSortDescriptors
let nameSortDescriptors = [
  NSSortDescriptor(key: "lastname", ascending: true),
  NSSortDescriptor(key: "firstname", ascending: true)
]
let ... = somePeople.sort(by: nameSortDescriptors.toCompareFunction())