Am I required to pass regular arguments before my subcommand?

[weezy20]

I have a simple struct with a subcommand and 1 argument:

#[derive(Debug, clap::Parser)]
#[command(version)]
struct Cli {
    #[clap(subcommand)]
    action: Action,
    /// Server location
    #[arg(short, long, default_value = "127.0.0.1:4000")]
    addr: String,
}

If I enter Action and then --adrr <..> I am told to pass it as separate arguments -- --addr <..> which is not correct (and should not be anyway). So my question is should I make addr part of the subcommand itself (this is irksome as my action is currently and enum and I would need to convert it to a struct), or is there a better alternative?

[epage]

Once we start parsing a subcommand, we cannot parse arguments from a parent command. There is a caveat to this that I'll get to.

Is addr truly universal between your subcommands or is this purely for coding convenience? From a CLI design perspective, I generally recommend that the focus be on arguments to your subcommands. The reason to have arguments on your parent command are if they are mutually exclusive with commands (e.g. cargo --list) or if they are orthogonal to subcommands (e.g. cargo --verbose) but even those can be suspect as it is generally expected to run cargo check -v rather than cargo -v check. It is also easy to think that an argument is universal to all commands until a new command is added in which it isn't (this is true for several arguments shown in cargo -h). If an argument is orthogonal / universal, then you can specify global = true and it will appear in all subcommands and we'll propagate the value back up to the instance in the parent command.

[weezy20]

Thanks for your response. You make some good points. addr is universal atm but I don't see any reason that that should be the case in the future. I think what you're suggesting is to adopt [Options] like in this case, addr into the subcommand themselve.

[edit] just tried out global = true and it achieved the desired effect.

[epage]

It does apply it to the subcommands that you might add in the future where it doesn't make sense.

[weezy20]

Will keep that in mind. Thanks for your help!