作為學(xué)習(xí)指針與值接收器的一部分，我提到了：https://gobyexample.com/methods// This `area` method has a _receiver type_ of `*rect`.func (r *rect) area() int {    return r.width * r.height}// Methods can be defined for either pointer or value// receiver types. Here's an example of a value receiver.func (r rect) perim() int {    return 2*r.width + 2*r.height}func main() {    r := rect{width: 10, height: 5}    // Here we call the 2 methods defined for our struct.    fmt.Println("area: ", r.area())    fmt.Println("perim:", r.perim())    // Go automatically handles conversion between values    // and pointers for method calls. You may want to use    // a pointer receiver type to avoid copying on method    // calls or to allow the method to mutate the    // receiving struct.    rp := &r    fmt.Println("area: ", rp.area())    fmt.Println("perim:", rp.perim())}我不明白-->rp := &r   rp is a pointer or address of r為什么結(jié)果：rp.area()  is identical to r.area() rp.perim()  is identical to r.perim()指針 ：它們是內(nèi)存中 var 的地址。功能區(qū)（） 需要一個(gè)指針接收器。所以這是明確的rp.area（）（因?yàn)閞p是r的指針或地址）但是為什么這個(gè)r.area（）？r 不是指針，而是值同樣，perim需要一個(gè)值，我們使用指針作為接收器？rp.perim（）這也意味著什么：您可能希望使用指針接收器類型，以避免在方法調(diào)用時(shí)進(jìn)行復(fù)制，或允許方法改變接收結(jié)構(gòu)。to avoid copying on method calls or to allow the method to mutate the receiving struct.