Avoid auto exit when call help command

[CodeWenjiu]

I'm trying to use clap to parse commands that are not strictly from the command line.

#[derive(Parser)]
#[command(version, about)]
pub struct Cli {
    #[command(subcommand)]
    pub command: Option<Commands>,
}

#[derive(Subcommand)]
pub enum Commands {
    /// does testing things
    #[clap(visible_alias = "t")]
    Test {
        /// lists test values
        #[arg(short, long)]
        list: bool,
    },

    /// quit the program, not need any arguments
    #[clap(visible_alias = "q")]
    Quit {},
}

fn main() {
    loop {
        let mut input = String::new();
        io::stdin().read_line(&mut input).unwrap();
        let mut input: Vec<&str> = input.trim().split_whitespace().collect::<Vec<&str>>();
        input.insert(0, ""); // Insert a dummy value

        let cli = cmd::Cli::parse_from(input);

        if let Some(cmd) = cli.command {
            match cmd {
                cmd::Commands::Quit {} => break,
                _ => (),
            }
        }
    }
}

Currently, it works well, but there is an issue: when clap parses the help command, it automatically exits the program, which is not what I expect. Is there a solution to this problem?

[epage]

parse_from is a function on the Parser trait. On that trait, you will also see a try_parse_from which will return an error.

You can also check out our REPL example

[CodeWenjiu]

Thank you for your reply, it perfectly solved my problem :)