Custom Operators in Swift

// Operator overloading
struct Vector2D {
    var x: Double
    var y: Double
}

// Addition operator
extension Vector2D {
    static func + (lhs: Vector2D, rhs: Vector2D) -> Vector2D {
        return Vector2D(x: lhs.x + rhs.x, y: lhs.y + rhs.y)
    }

    static func - (lhs: Vector2D, rhs: Vector2D) -> Vector2D {
        return Vector2D(x: lhs.x - rhs.x, y: lhs.y - rhs.y)
    }

    static func * (vector: Vector2D, scalar: Double) -> Vector2D {
        return Vector2D(x: vector.x * scalar, y: vector.y * scalar)
    }
}

// Compound assignment
extension Vector2D {
    static func += (lhs: inout Vector2D, rhs: Vector2D) {
        lhs = lhs + rhs
    }
}

// Custom operators
prefix operator +++
prefix func +++ (value: inout Int) -> Int {
    value += 2
    return value
}

infix operator **: MultiplicationPrecedence
func ** (base: Double, power: Double) -> Double {
    return pow(base, power)
}