Cobra: Ability to define arguments as well (like flags)

[andygrunwald]

Thanks for cobra. It is a really incredible project. Kudos.

In the PHP language there is a similar library quite popular: symfony/console.
In this library you are able to define flags and _arguments_ and access them via names.
This makes development quite readable and convenient.

In cobra arguments are treated as a slice / list instead of defined names. See cobra/cmd/add.go#L47 as an example.

In symfony/console you would write something like

protected function configure()
{
    $this
       // ...
        ->addArgument('name', InputArgument::REQUIRED, 'Who do you want to greet?')
        ->addArgument('last_name', InputArgument::OPTIONAL, 'Your last name?')
    ;
}

and access it like

protected function execute(InputInterface $input, OutputInterface $output)
{
    $text = 'Hi '.$input->getArgument('name');

    $lastName = $input->getArgument('last_name');
    if ($lastName) {
        $text .= ' '.$lastName;
    }

    $output->writeln($text.'!');
}

A matching call would look like php appname Andy Grunwald.

Did you considered such a behaviour for cobra as well?
What is your opinion about it?

I don`t know much about cobras internal codebase (yet), but i assume this wouldnt be a BC.
I like to hear your opinion and feedback about it.

A few documentation references that might be useful for this:

• Symfony/Console docs
• Console Input (Arguments & Options) @ Symfony/Console docs
• Understanding how Console Arguments Are Handled @ Symfony/Console docs

[cdhunt]

Coming from the world of PowerShell, I would like to see an option to define a position for flags that would bind positional arguments.

RootCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read from", 0)

So the following commands would be valid.

myexe --source /src
myexe -s /src
myexe /src

All three bind to Source. Any arguments after that would go to []args.

I'm not sure if that's taboo in the POSIX world, but it makes for a convenient command-line user experience.

[bogem]

Some progress was made in #284

[Naatan]

While relevant, I don't think #284 is the same as this. This asks for a way to properly specify and document arguments, and likely some type of automation of what #284 added.

[ceejatec]

Agreed. I'd go one step further and say there should be the ability to validate types of positional arguments as well. I can already specify that my command takes a --foo argument whose value is of type int, and cobra/pflags will validate the user's input, convert it to an int, and bind it to a corresponding variable. But if I want it as a positional argument I have to roll my own everything.

[ceejatec]

Python's built-in argparse library handles this very smoothly. There's no difference at all between a positional and flag-based argument except that one is named eg. "foo" and the other is named "--foo". Everything else - typing, validation, number of values, etc - is exactly the same. And the auto-generated help output documents them all correctly.

[github-actions[bot]]

This issue is being marked as stale due to a long period of inactivity