Methods in Go can have a struct receiver or a pointer receiver. For example, given a Person struct:
type Person struct {
name string
}
You could implement a Hello() method as either
func (p Person) Hello() string {
return "Hello " + p.name
}
or
func (p *Person) Hello() string {
return "Hello " + p.name
}
The difference between the two is what p is: in the case of the former, p is a copy of the Person struct, and any changes you make won't be reflected in the caller.
In the case of the latter -- where p is a pointer receiver, *Person -- p is mutable, and its contents can be changed. Another difference is that when you use a pointer receiver the contents of p don't need to be copied before executing the Hello() method. This can be really important for large structs.