I have working code, but not sure is this correct way to implement it.
CLi program will accept 4 argument, there can be present zero, all or any combination in between.
This is working code:
#[derive(Parser, Default, Debug)]
struct Arguments {
#[clap(short, long, default_value_t = false)]
/// if areas.csv to download
areas: bool,
#[clap(short, long, default_value_t = false)]
/// if markers.csv to download
markers: bool,
#[clap(short, long, default_value_t = false)]
/// if tracks.csv to download
tracks: bool,
#[clap(short, long)]
/// path to file of GPS tracks to download
gpx_list_file: Option<String>,
}
what I do not like is that in -h section there is no way to know that they are optional.
Options:
-a, --areas if areas.csv to download
-m, --markers if markers.csv to download
-t, --tracks if tracks.csv to download
-g, --gpx-list-file <GPX_LIST_FILE> path to file of GPS tracks to download
-h, --help Print help information
-V, --version Print version information
I know that I could add text like "This is optional field", but I have feeling that there is better way.
Also what is best way to know if I have 0 argument.
Currently I use this.
if (args.areas, args.markers, args.tracks, args.gpx_list_file.is_none()) == (false, false, false, true) {
println!("Nothing to download.");
exit(5);
}
It's perhaps a bit confusing. When a named argument is optional, you don't see anything telling you that specifically; you just get something like this:
Usage: command [OPTIONS]
Options:
-a, --areas if areas.csv to download
-n, --number <NUMBER> [default: 1]
-h, --help Print help information
-V, --version Print version information
When --areas is required, the help output now includes --areas in the "Usage:" line:
Usage: command [OPTIONS] --areas
Options:
-a, --areas if areas.csv to download
-n, --number <NUMBER> [default: 1]
-h, --help Print help information
-V, --version Print version information
The presence of --areas in the Usage section lets you know it's required, and its absence tells you it's optional.