通过Golang中的方法更改类型的基础值

Question

Can an instance of a go type change its underlying value? Thanks to a previous question I know I can make my function's receiver a pointer and change struct fields if my type is a struct.

However, I'm interesting in changing the underlying type's value. Consider a small program like this

type Foo string

func (f *Foo) ChangeMe() {
  val := Foo("Hello World")
  f = &val
  //fmt.Println(*f)
}

func main() {
  f := Foo("Nope")
  f.ChangeMe()
  fmt.Println(f)
}

My naive assumption was "OK, I've created a new Foo("Hello World") and then pointed f at it. Since receiver is a pointer (*Foo), this should change the value in main().

However, this does not work. The above program still prints out "Nope"

Interested both in what my incorrect assumption about go are, and any techniques for achieving what I want to do.

Answer 1

You're assigning a new pointer value to f instead of dereferencing it.

Dereference f and assign a new string value:

func (f *Foo) ChangeMe() {
    *f = Foo("Hello World")
}