Golang接口和* interface

Question

I am trying to use interfaces more in my codebase for a game server I am writing and understand the high level concept and when one should be used (I think). In my case I am using them to decouple my packages from one another amongst other as well as make testing easier.

My question boils down to I have a struct which has ptr receive methods. I am then passing this struct to another function via an interface just like in this playground I am confused as to why a function with a parameter of type interface can accept an address to something that implements that interface. Why is it not func something(f *face), what purpose does *interface serve?

Answer 1

It is not the case that "a parameter of type interface can accept an address to something that implements that interface". Quite the opposite.

Your concrete foo does not implement the interface face. It doesn't.

Only *foo does which is a different type in Go.

You can only assign *foo to variables of type face. (Okay, there is some sugar in Go which might let you an addressable foo to a face, but here the process of taking the pointer is automatic).

Take a look at the language spec and the type system.