builderpattern

type Lunch struct {
	Bread, Condiments, Dressing, Meat string
}

type LunchBuilder interface {
	Bread(bread string) LunchBuilder
	Condiments(condiments string) LunchBuilder
	Dressing(dressing string) LunchBuilder
	Meat(meat string) LunchBuilder
	Build() Lunch
}

type MyLunch struct {
	Lunch
}