golang how to overwrite function like this [duplicate] - go

Question

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Closed 8 months ago.
I have the following:
type A struct {
}
func (t *A) Do() {
print("A")
}
func (t *A) Display() {
t.Do()
}
type B struct {
A
}
func (t *B) Do() {
print("B")
}
And I will do like this
func TestC(t *testing.T) {
b := new(B)
// it will print "A", I neet it calling B's Do()
b.Display()
}
How to implement this, like java's abstruct class

Answer 1

It might be possible, but this isn't really how Go works. Go doesn't have classes, just structs, and structs can't be inherited, like classes can be. What you're doing here is embedding an A inside B. B then has:
b.Do
b.A.Display
b.A.Do
as it's "methods". There is no B.Display, so b.Do won't be called, because b.A.Display will be called instead.
There's not one specific way to do what you want as an alternative. You likely need to rethink how you would solve this problem. One possible solution is to define an interface, and then type your functions based on that interface. e.g.
type DoDisplay interface {
Do()
Display()
}
func IDo(obj DoDisplay) {
obj.Do()
}
func IDisplay(obj DoDisplay) {
obj.Display()
}
You would still need to define the Display method on B, and it very likely will still be the same as A. Other solutions might be to define a base type, and inject a specific do function to the struct (though I'd say that's a special case and not a recommended practice). Another solution might involve generics. There's also the ability to ask Go to generate code for you for these kinds of scenarios. But, the interface is likely the first thing you should try.