d1.go

package pizza

type Pizza interface {
    GetPrice() float64
    GetDescription() string
}

type Margherita struct{}

func (m *Margherita) GetPrice() float64 {
    return 10.0
}

func (m *Margherita) GetDescription() string {
    return "Margherita"
}

type ToppingDecorator struct {
    Pizza Pizza
}

func (t *ToppingDecorator) GetPrice() float64 {
    return t.Pizza.GetPrice()
}

func (t *ToppingDecorator) GetDescription() string {
    return t.Pizza.GetDescription()
}

type Cheese struct {
    *ToppingDecorator
}

func (p *Cheese) GetPrice() float64 {
    return p.ToppingDecorator.GetPrice() + 2
}

func (p *Cheese) GetDescription() string {
    return p.ToppingDecorator.GetDescription() + ", Cheese"
}

type Mushroom struct {
    *ToppingDecorator
}

func (m *Mushroom) GetPrice() float64 {
    return m.ToppingDecorator.GetPrice() + 1.5
}

func (m *Mushroom) GetDescription() string {
    return m.ToppingDecorator.GetDescription() + ", mushroom"
}