func F(f func()interface{})interface{} {
return f()
}
func one() int {
return 1
}
type A struct {}
func two() A {
return A{}
}
func main() {
a := F(one)
b := F(two)
}
The code above will fail with error
cannot use one (type func() int) as type func() interface {} in argument to F
cannot use two (type func() A) as type func() interface {} in argument to F
My question is how to pass a func with any possible output as a parameter?
CodePudding user response：
A value of type int can be assigned to an interface{} variable; a value of type func() int can not be assigned to a value of type func() interface{}. This is true with any version of Go.
Thought, what you are attempting to do can be achieved with Go 1.18, where you can easily type-parametrize the function with T any (btw any is an alias of interface{}):
func callf[T any](f func() T) T {
return f()
}
func one() int {
return 1
}
type A struct {}
func two() A {
return A{}
}
func main() {
a := callf(one)
b := callf(two)
fmt.Println(a) // 1
fmt.Println(b) // {}
}