flagx

Package flagx implements some utilities for command-line flag parsing. It extends the functionalities of the standard flag package.

Main features:

• sub commands management
• alias of command and flag names
• array of string flag type
• check if a flag was passed

For example the next code defines an app Command instance with a sub-command with name action and aliases act, ac and a. Note that only the names of the sub-commands are defined; the command name itself is not defined in the Command type. The name of the root command is obtained from the os.Args[0] parameter.

var app = &flagx.Command{
    ParseExec: runApp,
    SubCmd: map[string]*flagx.Command{
        "action,act,ac,a": {
            ParseExec: runAction,
        },
    },
}

To execute the app Command instance with the command line arguments call the Run module function.

err := flagx.Run(app)

The Run module function in turn calls the ParseExec function of the app command or the action sub-command based on the command-line arguments. Each ParseExec function first parse the passed arguments, then execute the specific work.

func runAction(name string, arguments []string) error {
    var params []string
    fs := flag.NewFlagSet(name, flag.ContinueOnError)
    flagx.AliasedStringsVar(fs, &params, "params,p", "description of the parameters")

    err := fs.Parse(arguments)

    if err == nil {
        err = execAction(params) // execute the specific work
    }
    return err
}

The AliasedStringsVar function defines an array of strings flag with name params and alias p. The command-line

app action --params str1,str2 -p str3 -params str4 -p str5,str6

will execute the execAction function with []string{"str1", "str2", "str3", "str4", "str5", "str6"} strings.

See test for more informations and usage examples.