Optional subcommands after positional args.

[mstendorf]

Hi,

I am trying to achieve a cli interface like this:

app foo 123
app foo 123 bar
app foo 123 bar baz
app foo 123 bar fuu 234

In this structure the app foo 123 would reference a foo object with id 123. The command app foo 123 bar would execute the bar command for the foo object with id 123 etc.
app foo 123 bar baz would then again be a nested optional subcommand under bar. All theese nested subcommands would need access to the id of foo, eg. the command app foo 123 bar fuu 234 fuu would need both arguments to function properly.

I know i could structure my cli interface another way, but I like the idea of having the arguments next to the command it relates to.
I could probably also get away with using flags for the id's but I prefer using flags to modify behaviour instead of requiring them to operate properly.

A real world example could be something like:
app user 123 search mac aa:bb:cc:dd:ee:ff

Here the app would search for a mac address for a given user, the user might be in a given organisation and would then have to search only that organisations devices etc.

This might just be a skill issue on my part, but I can't seem to make kong behave this way? Is it me not entirely understanding how to structure the cmd interface or is this not possible?

[alecthomas]

It's hard to say without knowing what you've tried, but you want branching positional arguments, then to access the value you can inject the struct into your Run() method. Kong automatically makes all parent nodes available for injection.

[mstendorf]

Thanks so much for taking the time to answer this.
That indeed got me a little further. I can now use the prefix argument in the subcommand by injecting the parent into the Run command.

I do still have some issues with the optional. subcommand part though.

This is my current test code.

type Refid struct {
	Refid    int      `arg:"" name:"refid" help:"The refid of the customer"`
	Internet Internet `cmd:""`
}

func (r *Refid) Run() error {
	fmt.Println("Refid", r.Refid)
	return nil
}

type CustomerCmd struct {
	Refid Refid `arg:""`
}

type Internet struct {
}

func (i *Internet) Run(r *Refid) error {
	fmt.Println("Internet", r.Refid)
	return nil
}

var CLI struct {
	Customer CustomerCmd `cmd:""`
}

func main() {
	cli := kong.Parse(&CLI)
	err = cli.Run()
	cli.FatalIfErrorf(err)
}

I can now do:
app customer 12 internet

But this fires the run method of both the Refid struct and the Internet struct - it should ideally only fire the run method of the Internet struct.

I cant do:
app customer 123

It expects the internet subcommand to always be there. Is it possible to have optional sub commands after args?

[alecthomas]

It expects the internet subcommand to always be there. Is it possible to have optional sub commands after args?

This can only be achieved by tagging one of the sub-commands as default:""