A wrapper for the flag package to define commands which lazy-load subcommands.

Example

package main

import (
	"fmt"
	"os"

	"github.com/ferroxyl/cmd"
)

// Define a new cli
var app = cmd.New("example", "0.0.0")

// Define a subcommand 'version' by satisfying the Cmd interface
type Version struct{}

func (s *Version) Description() string {
	return "Print the version"
}

func (s *Version) Init() *flag.FlagSet {
	return nil
}

func (s *Version) Run(args []string) error {
	if _, err := fmt.Printf("%s\n", "example v1.0.0"); err != nil {
		return err
	}
	return nil
}

func init() {
	// Register a subcommand
	app.Register("version", &cli.Version{})
}

func main() {
	// Custom message to show if no subcommands are provided
	if len(os.Args) < 2 {
		fmt.Println("No command provided. Use 'example -h' for more info.")
		os.Exit(1)
	}

	// Run the provided subcommand or return the error and usage
	if err := app.Run(os.Args[1]); err != nil {
		fmt.Printf("example: %s\n", err)
		app.Usage()
		os.Exit(1)
	}

	os.Exit(0)
}