在go（golang）中传递指向字符串的指针有什么意义？

Question

I was reading the following conversation about go (golang) strings. Strings in go are just a pointer to a (read-only) array and a length. Thus, when you pass them to a function the pointers are passed as value instead of the whole string. Therefore, it occurred to me, if that is true, then why are you even allowed to define as a function with a signature that takes *string as an argument? If the string is already doing plus, the data is immutable/read-only, so you can't change it anyway. What is the point in allowing go to pass pointers to strings if it already does that internally anyway?

Answer 1

You pass a pointer to the "object" holding the string, which then you can assign something different to it.

Example: http://play.golang.org/p/Gsybc7Me-5

func ps(s *string) {
    *s = "hoo"
}
func main() {
    s := "boo"
    ps(&s)
    fmt.Println(s)
}