在Go中调用将接口作为参数的函数

Question

How do you construct an interface as a parameter to a function?

type blahinterface interface {
    method1()
    method2()
    method3()
}

func blah (i blahinterface) {

}


blah(?)  < what goes in here

Answer 1

Actually, if you try to put anything "in here", the compiler will tell you precisely what is missing:

type S struct{}

func main() {
    fmt.Println("Hello, playground")
    s := &S{}
    blah(s)
}

A go build on this example would tell you:

prog.go:20: cannot use s (type *S) as type blahinterface in argument to blah:
    *S does not implement blahinterface (missing method1 method)
 [process exited with non-zero status]

But with:

func (s *S) method1(){}
func (s *S) method2(){}
func (s *S) method3(){}

The program do compile just fine.

So even without reading about interfaces, you are guided and can guess what is missing.