//See the bottom of this file to check what you can do with this

let calendar = Calendar(identifier: .gregorian)

struct CalendarComponentAmount {
    let component: Calendar.Component
    let amount: Int
}

infix operator +: AdditionPrecedence
extension Date {
    
    static func +(date: Date, componentAmount: CalendarComponentAmount) -> Date {
        return calendar.date(byAdding: componentAmount.component,
                             value: componentAmount.amount, 
                             to: date)!
    }
}

extension Int {
    
    var years: CalendarComponentAmount {
        return CalendarComponentAmount(component: .year, amount: self)
    }
    
    var months: CalendarComponentAmount {
        return CalendarComponentAmount(component: .month, amount: self)
    }
    
    var days: CalendarComponentAmount {
        return CalendarComponentAmount(component: .day, amount: self)
    }
    
    var hours: CalendarComponentAmount {
        return CalendarComponentAmount(component: .hour, amount: self)
    }
    
    var minutes: CalendarComponentAmount {
        return CalendarComponentAmount(component: .minute, amount: self)
    }
    
    var seconds: CalendarComponentAmount {
        return CalendarComponentAmount(component: .second, amount: self)
    }
}

var d = Date()    => "Nov 15, 2016, 4:17 PM"

d + 1.years   => "Nov 15, 2017, 4:17 PM"
d + 2.months  => "Jan 16, 2017, 4:17 PM"
d + 3.days    => "Nov 18, 2016, 4:17 PM"
d + 4.hours   => "Nov 15, 2016, 8:17 PM"
d + 5.minutes => "Nov 15, 2016, 4:22 PM"
d + 60.seconds => "Nov 15, 2016, 4:18 PM"