Contents

interface

2020-05-14 194 words One minute

Contents

Interfaces Explained

1. what is

is a type
contain a set of method signature

2. used for

引入一个中间层，调用方和实现方解耦

3.type assertion vs type conversions

assertion: 将interface 抓换为具体类型

1
2


var a interface{} = 100;
var aa,ok = a.(string)

conversions

4. compile time check

5. interface with pointer and value

if methods receiver is value; then value and pointer implement the interface

for pointer, it could get value by dereference; then copy it;

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15


type Duck interface{ Quack() }

type Cat struct{ Name string }

func (c Cat) Quack() {

	fmt.Println("memo")
	c.Name = "abc"
}
func main() {
	var d Duck = &Cat{"jim"} // 使用结构体初始化变量
	d.Quack()
	fmt.Println(d)

}

if methods receiver is pointer, then only pointer implement the interface

for value receiver, it could not get origin pointer;

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14


type Duck interface{ Quack() }

type Cat struct{ Name string }

func (c *Cat) Quack() {

	fmt.Println("memo")
	c.Name = "abc"
}
func main() {
	var d Duck = Cat{"jim"} // 使用结构体初始化变量
	d.Quack()
	fmt.Println(d)
}

todolist

interface with compile time