Ability to know whether a short option or long option was used

[rossmacarthur]

Currently for the built-in -V, --version arg it is possible to have a different output for the short flag, -V, and the long flag --version, by setting version and long_version respectively. I would like to be able to use this behavior in a custom option but can't see of anyway to do it.

More specifically I want to output something different for --verbose --version while still having differing behavior for -V and --version.

[pksunkara]

You can set an arg with -V short which overrides the short of the built in version flag.

[rossmacarthur]

Could you give an example. What I want is a single Arg with -V and --version but after parsing I wish to know if it was -V that was passed or --version.

For example in the following example:

use clap::{App, AppSettings, Arg};

fn main() {
    let matches = App::new("test")
        .setting(AppSettings::NoAutoVersion)
        .arg(Arg::new("version").long("version").short('V'))
        .get_matches();
    println!("{:?}", matches.is_present("version"));
}

Is it possible for me to know if it was -V that was passed or --version.

[pksunkara]

You can't have that. What you can do is set 2 args, one with short flag and the other with long flag and do different behaviours.

[pksunkara]

So, If you add a new arg with only the short flag, now there will be 2 args since the builtin flag will only have long flag.