func runRoot()

in cmd/viewcore/main.go [295:368]
62 lines of code
12 McCabe index (conditional complexity)

func runRoot(cmd *cobra.Command, args []string) {
	if cfg.corefile == "" {
		cmd.Usage()
		return
	}
	p, _, err := readCore()
	if err != nil {
		exitf("%v\n", err)
	}

	// Interactive mode.
	cfg.interactive = true

	// Create a dummy root to run in shell.
	root := &cobra.Command{}
	// Make all subcommands of viewcore available in the shell.
	for _, subcmd := range cmd.Commands() {
		if subcmd.Name() == "help" {
			root.SetHelpCommand(subcmd)
			continue
		}
		root.AddCommand(subcmd)
	}
	// Also, add exit command to terminate the shell.
	root.AddCommand(&cobra.Command{
		Use:     "exit",
		Aliases: []string{"quit", "bye"},
		Short:   "exit from interactive mode",
		Run: func(*cobra.Command, []string) {
			os.Exit(0)
		},
	})

	rootCompleter := readline.NewPrefixCompleter()
	for _, child := range root.Commands() {
		cmdToCompleter(rootCompleter, child)
	}

	shell, err := readline.NewEx(&readline.Config{
		Prompt:       "(viewcore) ",
		AutoComplete: rootCompleter,
		EOFPrompt:    "\n",
	})
	if err != nil {
		panic(err)
	}
	defer shell.Close()

	// nice welcome message.
	fmt.Fprintln(shell.Terminal)
	if args := p.Args(); args != "" {
		fmt.Fprintf(shell.Terminal, "Core %q was generated by %q\n", cfg.corefile, args)
	}
	fmt.Fprintf(shell.Terminal, "Entering interactive mode (type 'help' for commands)\n")

	for {
		l, err := shell.Readline()
		if err != nil {
			if err != io.EOF {
				fmt.Printf("Error: %v\n", err)
			}
			break
		}

		err = capturePanic(func() {
			ResetSubCommandFlagValues(root)
			root.SetArgs(strings.Fields(l))
			root.Execute()
		})
		if err != nil {
			fmt.Printf("Error while trying to run command %q: %v", l, err)
		}
	}
}