c2.go

type GUI interface {
    Draw()
    HandleEvent(event interface{})
}

type Button struct {
    x, y, width, height int
    label string
}

func (b *Button) Draw() {
    // draw button on screen
}

func (b *Button) HandleEvent(event interface{}) {
    // handle button event
}

type Window struct {
    x, y, width, height int
    title string
    elements []GUI
}

func (w *Window) Draw() {
    // draw window on screen
    for _, element := range w.elements {
        element.Draw()
    }
}

func (w *Window) HandleEvent(event interface{}) {
    // handle window event
    for _, element := range w.elements {
        element.HandleEvent(event)
    }
}