package main

import "fmt"

type Boss struct{}

func (b *Boss) AssignWork() {

	fmt.Println("Boss assigned work")

}

type Manager struct{}

func (m *Manager) PreparePowerPoint() {

	fmt.Println("PowerPoint prepared")

}

type BossManager struct {

	Boss  // 嵌入式字段

	Manager  // 嵌入式字段

}

type BossManagerUsingPointers struct {

	*Boss  // 指针类型的嵌入式字段

	*Manager  // 指针类型的嵌入式字段

}

/*

BossManager和BossManagerUsingPointers的区别？

BossManage类型没有实现这个PromotionMaterial接口，BossManage的指针类型实现了这个接口

BossManagerUsingPointers类型实现了PromotionMaterial这个接口

BossManagerUsingPointers的指针类型也是PromotionMaterial这个接口类型

*/

// Define an interface that requires both methods.

type PromotionMaterial interface {

	AssignWork()

	PreparePowerPoint()

}

func promote(pm PromotionMaterial) {

	fmt.Println("Promoted a person with promise.")

}

func main() {

	bm := BossManager{}

	// Both methods (which use pointer receivers) have been promoted to BossManager.

	bm.AssignWork()        // "Boss assigned work"

	bm.PreparePowerPoint() // "PowerPoint prepared"

	// However, the method set of BossManager does not include either method because:

	// 1) {Boss, Manager} are embedded as value types, not pointer types.

	// 2) This makes it so that only the pointer type *BossManager includes both methods

	// in its method set, thus making it implement interface PromotionMaterial.

	// promote(bm)	// Would fail with: cannot use bm (type BossManager) as type PromotionMaterial in argument to promote:

	// BossManager does not implement PromotionMaterial (AssignWork method has pointer receiver)

	// This would work if {Boss, Manager} were embedded as pointer types.

	promote(&bm) // Works

	// Lets use the struct with the embedded pointer types:

	bm2 := BossManagerUsingPointers{}

	bm2.AssignWork()        // "Boss assigned work"

	bm2.PreparePowerPoint() // "PowerPoint prepared"

	promote(bm2)            // Works

	promote(&bm2)           // Also works, since both BossManagerUsingPointers (value type) and *BossManagerUsingPointers (pointer type)

	// method sets include both methods.

}