沙鷗工作室

• 首先要知道 a value can be more then one type
• a value can be more them one type
• a value can be more them one type

• type person struct {
  	first string
  	last  string
  }
  
  type secretAgent struct {
  	person
  	ltk bool
  }
  
  

   

• 
  func (s secretAgent) speak() {
  	fmt.Println("I am", s.first, s.last, " - the secretAgent speak")
  }
  
  func (p person) speak() {
  	fmt.Println("I and", p.first, p.last, " - the secretAgent speak")
  }

   

• type human interface {
  	// If you have this method then you are my type
  	// define which method a type must have to implement interface
  	speak()
  }

   

• 這邊的 type person 和 type secretAgent，都擁有 attach 的 speak method，所以符合 type human interface 的定義
• 那 type person 和 type secretAgent，就也同時是 type human 和 type person

package main

import "fmt"

type person struct {
	first string
	last  string
}

type secretAgent struct {
	person
	ltk bool
}

func (s secretAgent) speak() {
	fmt.Println("I am", s.first, s.last, " - the secretAgent speak")
}

func (p person) speak() {
	fmt.Println("I and", p.first, p.last, " - the secretAgent speak")
}

// keyword identifier type
// a value can be more then one type
// a value can be more then one type

type human interface {
	// If you have this method then you are my type
	// define which method a type must have to implement interface
	speak()
}

func bar(h human) {
	switch h.(type) {
	case person:
		fmt.Println("I was passed into barrrrrrr", h.(person).first)
	case secretAgent:
		fmt.Println("I was passed into barrrrrrr", h.(secretAgent).first)
	}
	fmt.Println("I was passed into bar", h)
}

type hotdog int

func main() {
	// sa1是type secretAgent，因為他有speak() method，所以sa1也同時是type human
	sa1 := secretAgent{
		person: person{
			"James",
			"Bond",
		},
		ltk: true,
	}

	sa2 := secretAgent{
		person: person{
			"Miss",
			"Moneypenny",
		},
		ltk: true,
	}

	p1 := person{
		first: "Dr.",
		last:  "Yes",
	}

	fmt.Println(sa1)
	fmt.Println(sa2)

	fmt.Println(p1)

	bar(sa1)
	bar(sa2)
	bar(p1)

	// conversion
	var x hotdog = 42
	fmt.Println(x)
	fmt.Printf("%T\n", x)
	var y int
	y = int(x)

	fmt.Println(y)
	fmt.Printf("%T\n", y)
}