Counter Options

[runeimp]

I'd love it if there was support for multiple instance options that count their repetition instead of accepting multiple values. This is commonly used for verbosity where a setup, something along the lines of

type args struct {
	Debug   bool   `arg:"-D" help:"output debug info"`
	Verbose uint8 `arg:"-v,counter" help:"Increases verbosity"`
}

would allow for --verbose blah -v on the command line would set args.verbose == 2, -vvv would set args.verbose == 3, etc. And not specifying any verbosity options would set args.verbose == 0.

[alexflint]

Hey @runeimp - thanks for the suggestion. This seems quite reasonable, but it also feels like it might only be used for the common "verbose" flag. I can't really think of another realistic use-case. I wonder if it would be better just to do it manually with something like

func main() {
  var verbose int
  for i, arg := range os.Args {
    if strings.TrimRight(arg, "v") == "-" {
      verbose = len(arg) - 1
      os.Args = append(os.Args[:i], os.Args[i+1:]...)
      break
    }
  }
  var args struct {
    ...
  }
  arg.MustParse(&args)
  ...
}

This seems like a reasonably small amount of code for the special case of "-v", whereas implementing the general version inside go-arg and covering all the corner cases feels like it would add quite a bit of complexity.

[runeimp]

I totally understand. I've seen it used in other places but verbosity is definitely the major use case. Thanks for the suggestion on how to work around it.