Swift Combined Comparison Operator

Combined Comparison.swift

infix operator <=> { associativity none precedence 130 }

func <=><T: Comparable>(lhs: T, rhs: T) -> NSComparisonResult {
    if lhs > rhs {
        return .OrderedDescending
    }
    else if lhs < rhs {
        return .OrderedAscending
    }
    else {
        return .OrderedSame
    }
}

// Super simple example

func isAffordable(cost: Int, money: Int) {
    switch cost <=> money {
    case .OrderedAscending:  println("We can buy it with $\(money-cost) left over!")
    case .OrderedSame:       println("We have just enough.")
    case .OrderedDescending: println("Insufficient funds :O")
    }
}

isAffordable(5, 9) // -> "We can buy it with $4 left over!"