select.swift

//select ::[a] ->[(a, [a])]
//select[] = []
//select(x:xs) = (x, xs) : [(y, x:ys) | (y, ys) <-select xs]

func select<T>(input: [T]) -> [(T, [T])] {
	if (input.isEmpty) {
		return []
	} else {
		let head = input[0]
		let rest = Array(input[1..<input.count])

		return [(head, rest)] + select(rest).map { ($0, [head] + $1) }
	}
}