func main() {
	flags := struct {
		Help      bool `short:"h" long:"help" description:"Display usage" global:"true"`
		Version   bool `short:"v" long:"version" description:"Display version"`
		VersionEx bool `long:"vv" description:"Display version (extended)"`
		Echo      struct {
			Settings bool `settings:"true" allow-unknown-arg:"true"`
		} `command:"echo" description:"Print arguments"`
		Math struct {
			Sqrt struct {
				Number float64 `short:"n" long:"number" required:"true" description:"Number"`
			} `command:"sqrt" description:"Calculate square root"`
			Pow struct {
				Base     float64 `short:"b" long:"base" required:"true" description:"Base"`
				Exponent float64 `short:"e" long:"exponent" required:"true" description:"Exponent"`
			} `command:"pow" description:"Calculate base exponential"`
		} `command:"math" description:"Math functions" nonempty:"true"`
	}{}

	// Echo command
	gocmd.HandleFlag("Echo", func(cmd *gocmd.Cmd, args []string) error {
		fmt.Printf("%s\n", strings.Join(cmd.FlagArgs("Echo")[1:], " "))
		return nil
	})

	// Math commands
	gocmd.HandleFlag("Math.Sqrt", func(cmd *gocmd.Cmd, args []string) error {
		fmt.Println(math.Sqrt(flags.Math.Sqrt.Number))
		return nil
	})
	gocmd.HandleFlag("Math.Pow", func(cmd *gocmd.Cmd, args []string) error {
		fmt.Println(math.Pow(flags.Math.Pow.Base, flags.Math.Pow.Exponent))
		return nil
	})

	// Init the app
	gocmd.New(gocmd.Options{
		Name:        "basic",
		Version:     "1.0.0",
		Description: "A basic app",
		Flags:       &flags,
		ConfigType:  gocmd.ConfigTypeAuto,
	})
}