Rust Clap custom headings

Question

I am using the rust Clap library to parse command line arguments. When displaying my help text I want to separate required arguments from optional arguments and put them under separate headings. Something along the lines of this:

HELP:
    Example header 1:
        Arg 1
        Arg 2

    Example header 2:
        Arg 3
        Arg 4

Is this possible.

After reading this, this and this I think it might be but I am not confident of how to go about doing so.

EDIT:
So a commentor has asked me to update the post with some desired output so below is an example from one of the links above. I would like to be able to have two options sections and name them.

$ myprog --help
My Super Program 1.0
Kevin K. 
Does awesome things

USAGE:
    MyApp [FLAGS] [OPTIONS]  [SUBCOMMAND]

FLAGS:
    -h, --help       Prints this message
    -v               Sets the level of verbosity
    -V, --version    Prints version information

OPTIONS:
    -c, --config     Sets a custom config file

ARGS:
    INPUT    The input file to use

SUBCOMMANDS:
    help    Prints this message
    test    Controls testing features

So changing the OPTIONS section above to be:

OPTIONS-1:
    -c, --config     Sets a custom config file.

OPTIONS-2:
    -a, --another     Another example command.

user_1113913 · Answer

I think you might be looking for help_heading. It seems this has been added recently, so you'll have to grab the very latest commit.

cargo.toml

[dependencies]
clap = { git = "https://github.com/clap-rs/clap", rev = "8145717" }

main.rs

use clap::Clap;

#[derive(Clap, Debug)]
#[clap(
    name = "My Application",
    version = "1.0",
    author = "Jason M.",
    about = "Stack Overflow"
)]
struct Opts {
    #[clap(
        help_heading = Some("OPTIONS-1"),
        short,
        long,
        value_name="FILE",
        about = "Sets a custom config file"
    )]
    config: String,
    #[clap(
        help_heading = Some("OPTIONS-2"),
        short,
        long,
        value_name="FILE",
        about = "Another example command"
    )]
    another: String,
}

fn main() {
    let opts: Opts = Opts::parse();
}

use clap::{App, Arg};

fn main() {
    let app = App::new("My Application")
        .version("1.0")
        .author("Jason M.")
        .about("Stack Overflow")
        .help_heading("OPTIONS-1")
        .arg(
            Arg::new("config")
                .short('c')
                .long("config")
                .value_name("FILE")
                .about("Sets a custom config file"),
        )
        .help_heading("OPTIONS-2")
        .arg(
            Arg::new("another")
                .short('a')
                .long("another")
                .value_name("FILE")
                .about("Another example command"),
        );

    app.get_matches();
}

Either of the above will generate the following upon running cargo run -- --help:

My Application 1.0
Jason M.
Stack Overflow

USAGE:
    clap_headings --config  --another 

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS-1:
    -c, --config     Sets a custom config file

OPTIONS-2:
    -a, --another     Another example command

Rust Clap custom headings

1 Answers