Swift - 自定义运算符

precedencegroup PlusMinusPrecedence {
    
    associativity: none
    higherThan: AdditionPrecedence
    lowerThan: MultiplicationPrecedence
    assignment: true
    
}

infix operator +- : PlusMinusPrecedence

struct Point {
    
    var x = 0, y = 0
    static func +- (p1:Point,p2:Point) -> Point {
        
        Point(x: p1.x+p2.x, y: p1.y - p2.y)
    }
    
}

上述代码中，我们自定义了一个运算符，对Point的x相加，对Point的y进行相减

var p1 = Point(x: 10, y: 10)
var p2 = Point(x: 15, y: 20)
var p3 = p2 +- p1