clap Documentation

$ cargo add clap

use clap::{builder::PossibleValue, Arg, ArgAction, Command, ValueHint};
use clap_complete::generate;
use clap_complete_nushell::Nushell;
use std::io;

fn main() {
    let mut cmd = Command::new("myapp")
        .version("3.0")
        .propagate_version(true)
        .about("Tests completions")
        .arg(
            Arg::new("file")
                .value_hint(ValueHint::FilePath)
                .help("some input file"),
        )
        .arg(
            Arg::new("config")
                .action(ArgAction::Count)
                .help("some config file")
                .short('c')
                .visible_short_alias('C')
                .long("config")
                .visible_alias("conf"),
        )
        .arg(Arg::new("choice").value_parser(["first", "second"]))
        .subcommand(
            Command::new("test").about("tests things").arg(
                Arg::new("case")
                    .long("case")
                    .action(ArgAction::Set)
                    .help("the case to test"),
            ),
        )
        .subcommand(
            Command::new("some_cmd")
                .about("top level subcommand")
                .subcommand(
                    Command::new("sub_cmd").about("sub-subcommand").arg(
                        Arg::new("config")
                            .long("config")
                            .action(ArgAction::Set)
                            .value_parser([PossibleValue::new("Lest quotes aren't escaped.")])
                            .help("the other case to test"),
                    ),
                ),
        );

    generate(Nushell, &mut cmd, "myapp", &mut io::stdout());
}

module completions {

  def "nu-complete myapp choice" [] {
    [ "first" "second" ]
  }

  # Tests completions
  export extern myapp [
    file?: string             # some input file
    --config(-c)              # some config file
    --conf                    # some config file
    -C                        # some config file
    choice?: string@"nu-complete myapp choice"
    --version(-V)             # Print version
  ]

  # tests things
  export extern "myapp test" [
    --case: string            # the case to test
    --version(-V)             # Print version
  ]

  # top level subcommand
  export extern "myapp some_cmd" [
    --version(-V)             # Print version
  ]

  def "nu-complete myapp some_cmd sub_cmd config" [] {
    [ "\"Lest quotes aren't escaped.\"" ]
  }

  # sub-subcommand
  export extern "myapp some_cmd sub_cmd" [
    --config: string@"nu-complete myapp some_cmd sub_cmd config" # the other case to test
    --version(-V)             # Print version
  ]

}

use completions *

$ cargo add --build clap_mangen

fn main() -> std::io::Result<()> {
    let out_dir = std::path::PathBuf::from(std::env::var_os("OUT_DIR").ok_or(std::io::ErrorKind::NotFound)?);

    let cmd = clap::Command::new("mybin")
        .arg(clap::arg!(-n --name <NAME>))
        .arg(clap::arg!(-c --count <NUM>));

    let man = clap_mangen::Man::new(cmd);
    let mut buffer: Vec = Default::default();
    man.render(&mut buffer)?;

    std::fs::write(out_dir.join("mybin.1"), buffer)?;

    Ok(())
}