Swift中的运算符优先级重载

class Vector{
    var x:Int
    var y:Int
    init(x _x:Int,y _y:int){
        self.x = _x
        self.y = _y
    }
}

func *(lhs:Vector,rhs:Vector)->Int{
    return lhs.x * rhs.y + rhs.x + rhs.y
}

func +(lhs:Vector,rhs:Vector)->Vector{
    return Vector(x: lhs.x + rhs.x,y: lhs.y + rhs.y)
}

var v1 = Vector(x: 6,y: 1)
var v2 = Vector(x: 3,y: 1)


v1 * v2 + v1