问题
For example in the following example:
type Food interface {
Eat() bool
}
type vegetable_s struct {
//some data
}
type Vegetable *vegetable_s
type Salt struct {
// some data
}
func (p Vegetable) Eat() bool {
// some code
}
func (p Salt) Eat() bool {
// some code
}
Do Vegetable and Salt both satisfy Food, even though one is a pointer and the other is directly a struct?
回答1:
The answer is easy to get by compiling the code:
prog.go:19: invalid receiver type Vegetable (Vegetable is a pointer type)
The error is based on the specs requirement of:
The receiver type must be of the form T or *T where T is a type name. The type denoted by T is called the receiver base type; it must not be a pointer or interface type and it must be declared in the same package as the method.
(Emphasizes mine)
The declaration:
type Vegetable *vegetable_s
declares a pointer type, ie. Vegetable is not eligible as a method receiver.
回答2:
You could do the following:
package main
type Food interface {
Eat() bool
}
type vegetable_s struct {}
type Vegetable vegetable_s
type Salt struct {}
func (p *Vegetable) Eat() bool {return false}
func (p Salt) Eat() bool {return false}
func foo(food Food) {
food.Eat()
}
func main() {
var f Food
f = &Vegetable{}
f.Eat()
foo(&Vegetable{})
foo(Salt{})
}
来源：https://stackoverflow.com/questions/17902127/in-go-can-both-a-type-and-a-pointer-to-a-type-implement-an-interface