Type safety, and the lack of fields in interfaces. In C you have to pass the size of the elements to quicksort, but in Go you can't do that without using the unsafe module. So you need a virtual Swap() method. And because Go needs to take a single interface, and interfaces in Go can't have fields, you need a Len() method as well.
Comments
I am not sure I understand why you need generics for this, doesn't C get by passing a single function pointer?
Could you explain why Go needs an interface with 3 methods?
Type safety, and the lack of fields in interfaces. In C you have to pass the size of the elements to quicksort, but in Go you can't do that without using the unsafe module. So you need a virtual Swap() method. And because Go needs to take a single interface, and interfaces in Go can't have fields, you need a Len() method as well.
thanks I think I understand now.