[设计模式 Go实现] 行为型～备忘录模式

package memento

import "fmt"

type Memento interface{}

type Game struct {
    hp, mp int
}

type gameMemento struct {
    hp, mp int
}

func (g *Game) Play(mpDelta, hpDelta int) {
    g.mp += mpDelta
    g.hp += hpDelta
}

func (g *Game) Save() Memento {
    return &gameMemento{
        hp: g.hp,
        mp: g.mp,
    }
}

func (g *Game) Load(m Memento) {
    gm := m.(*gameMemento)
    g.mp = gm.mp
    g.hp = gm.hp
}

func (g *Game) Status() {
    fmt.Printf("Current HP:%d, MP:%d\n", g.hp, g.mp)
}

package memento

func ExampleGame() {
    game := &Game{
        hp: 10,
        mp: 10,
    }

    game.Status()
    progress := game.Save()

    game.Play(-2, -3)
    game.Status()

    game.Load(progress)
    game.Status()

    // Output:
    // Current HP:10, MP:10
    // Current HP:7, MP:8
    // Current HP:10, MP:10
}