如何在Go中声明指向方法的函数指针

Question

I am trying to create function pointer to a function that has a method receiver. However, I can't figure out how to get it to work (if it is possible)?

Essentially, I have the following:

type Foo struct {...}
func (T Foo) Bar bool {
   ... 
}

type BarFunc (Foo) func() bool // Does not work.

The last line of the code gives the error

syntax error: unexpected func, expecting semicolon or newline

Answer 1

If you want to create a function pointer to a method, you have two ways. The first is essentially turning a method with two arguments into a function with one:

type Summable int

func (s Summable) Add(n int) int {
    return s+n
}

var f func(s Summable, n int) int = (Summable).Add

// ...
fmt.Println(f(1, 2))

The second way will "bind" the function to the method's receiver:

s := Summable(1)
var f func(n int) int = s.Add
fmt.Println(f(2))

Playground: http://play.golang.org/p/ctovxsFV2z.