Struct clap::builder::Command

source ·
pub struct Command { /* private fields */ }
Expand description

Build a command-line interface.

This includes defining arguments, subcommands, parser behavior, and help output. Once all configuration is complete, the Command::get_matches family of methods starts the runtime-parsing process. These methods then return information about the user supplied arguments (or lack thereof).

When deriving a Parser, you can use CommandFactory::command to access the Command.

Examples

let m = Command::new("My Program")
    .author("Me, me@mail.com")
    .version("1.0.2")
    .about("Explains in brief what the program does")
    .arg(
        Arg::new("in_file")
    )
    .after_help("Longer explanation to appear after the options when \
                 displaying the help information from --help or -h")
    .get_matches();

// Your program logic starts here...

Implementations§

Creates a new instance of an Command.

It is common, but not required, to use binary name as the name. This name will only be displayed to the user when they request to print version or help and usage information.

See also command! and crate_name!.

Examples
Command::new("My Program")
Examples found in repository?
src/builder/debug_asserts.rs (line 855)
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fn assert_defaults<'d>(
    arg: &Arg,
    field: &'static str,
    defaults: impl IntoIterator<Item = &'d OsStr>,
) {
    for default_os in defaults {
        let value_parser = arg.get_value_parser();
        let assert_cmd = Command::new("assert");
        if let Some(delim) = arg.get_value_delimiter() {
            let default_os = RawOsStr::new(default_os);
            for part in default_os.split(delim) {
                if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), &part.to_os_str())
                {
                    panic!(
                        "Argument `{}`'s {}={:?} failed validation: {}",
                        arg.get_id(),
                        field,
                        part.to_str_lossy(),
                        err
                    );
                }
            }
        } else if let Err(err) = value_parser.parse_ref(&assert_cmd, Some(arg), default_os) {
            panic!(
                "Argument `{}`'s {}={:?} failed validation: {}",
                arg.get_id(),
                field,
                default_os,
                err
            );
        }
    }
}
More examples
Hide additional examples
src/builder/command.rs (line 4273)
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    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

Adds an argument to the list of valid possibilities.

Examples
Command::new("myprog")
    // Adding a single "flag" argument with a short and help text, using Arg::new()
    .arg(
        Arg::new("debug")
           .short('d')
           .help("turns on debugging mode")
    )
    // Adding a single "option" argument with a short, a long, and help text using the less
    // verbose Arg::from()
    .arg(
        arg!(-c --config <CONFIG> "Optionally sets a config file to use")
    )
Examples found in repository?
src/builder/command.rs (line 202)
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    pub fn args(mut self, args: impl IntoIterator<Item = impl Into<Arg>>) -> Self {
        for arg in args {
            self = self.arg(arg);
        }
        self
    }

    /// Allows one to mutate an [`Arg`] after it's been added to a [`Command`].
    ///
    /// This can be useful for modifying the auto-generated help or version arguments.
    ///
    /// # Panics
    ///
    /// If the argument is undefined
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    ///
    /// let mut cmd = Command::new("foo")
    ///     .arg(Arg::new("bar")
    ///         .short('b')
    ///         .action(ArgAction::SetTrue))
    ///     .mut_arg("bar", |a| a.short('B'));
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "-b"]);
    ///
    /// // Since we changed `bar`'s short to "B" this should err as there
    /// // is no `-b` anymore, only `-B`
    ///
    /// assert!(res.is_err());
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "-B"]);
    /// assert!(res.is_ok());
    /// ```
    #[must_use]
    #[cfg_attr(debug_assertions, track_caller)]
    pub fn mut_arg<F>(mut self, arg_id: impl AsRef<str>, f: F) -> Self
    where
        F: FnOnce(Arg) -> Arg,
    {
        let id = arg_id.as_ref();
        let a = self
            .args
            .remove_by_name(id)
            .unwrap_or_else(|| panic!("Argument `{}` is undefined", id));

        self.args.push(f(a));
        self
    }

    /// Allows one to mutate a [`Command`] after it's been added as a subcommand.
    ///
    /// This can be useful for modifying auto-generated arguments of nested subcommands with
    /// [`Command::mut_arg`].
    ///
    /// # Panics
    ///
    /// If the subcommand is undefined
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    ///
    /// let mut cmd = Command::new("foo")
    ///         .subcommand(Command::new("bar"))
    ///         .mut_subcommand("bar", |subcmd| subcmd.disable_help_flag(true));
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "bar", "--help"]);
    ///
    /// // Since we disabled the help flag on the "bar" subcommand, this should err.
    ///
    /// assert!(res.is_err());
    ///
    /// let res = cmd.try_get_matches_from_mut(vec!["foo", "bar"]);
    /// assert!(res.is_ok());
    /// ```
    #[must_use]
    pub fn mut_subcommand<F>(mut self, name: impl AsRef<str>, f: F) -> Self
    where
        F: FnOnce(Self) -> Self,
    {
        let name = name.as_ref();
        let pos = self.subcommands.iter().position(|s| s.name == name);

        let subcmd = if let Some(idx) = pos {
            self.subcommands.remove(idx)
        } else {
            panic!("Command `{}` is undefined", name)
        };

        self.subcommands.push(f(subcmd));
        self
    }

    /// Adds an [`ArgGroup`] to the application.
    ///
    /// [`ArgGroup`]s are a family of related arguments.
    /// By placing them in a logical group, you can build easier requirement and exclusion rules.
    ///
    /// Example use cases:
    /// - Make an entire [`ArgGroup`] required, meaning that one (and *only*
    ///   one) argument from that group must be present at runtime.
    /// - Name an [`ArgGroup`] as a conflict to another argument.
    ///   Meaning any of the arguments that belong to that group will cause a failure if present with
    ///   the conflicting argument.
    /// - Ensure exclusion between arguments.
    /// - Extract a value from a group instead of determining exactly which argument was used.
    ///
    /// # Examples
    ///
    /// The following example demonstrates using an [`ArgGroup`] to ensure that one, and only one,
    /// of the arguments from the specified group is present at runtime.
    ///
    /// ```no_run
    /// # use clap::{Command, arg, ArgGroup};
    /// Command::new("cmd")
    ///     .arg(arg!("--set-ver [ver] 'set the version manually'"))
    ///     .arg(arg!("--major 'auto increase major'"))
    ///     .arg(arg!("--minor 'auto increase minor'"))
    ///     .arg(arg!("--patch 'auto increase patch'"))
    ///     .group(ArgGroup::new("vers")
    ///          .args(["set-ver", "major", "minor","patch"])
    ///          .required(true))
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    pub fn group(mut self, group: impl Into<ArgGroup>) -> Self {
        self.groups.push(group.into());
        self
    }

    /// Adds multiple [`ArgGroup`]s to the [`Command`] at once.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, arg, ArgGroup};
    /// Command::new("cmd")
    ///     .arg(arg!("--set-ver [ver] 'set the version manually'"))
    ///     .arg(arg!("--major         'auto increase major'"))
    ///     .arg(arg!("--minor         'auto increase minor'"))
    ///     .arg(arg!("--patch         'auto increase patch'"))
    ///     .arg(arg!("-c [FILE]       'a config file'"))
    ///     .arg(arg!("-i [IFACE]      'an interface'"))
    ///     .groups([
    ///         ArgGroup::new("vers")
    ///             .args(["set-ver", "major", "minor","patch"])
    ///             .required(true),
    ///         ArgGroup::new("input")
    ///             .args(["c", "i"])
    ///     ])
    /// # ;
    /// ```
    #[must_use]
    pub fn groups(mut self, groups: impl IntoIterator<Item = impl Into<ArgGroup>>) -> Self {
        for g in groups.into_iter() {
            self = self.group(g.into());
        }
        self
    }

    /// Adds a subcommand to the list of valid possibilities.
    ///
    /// Subcommands are effectively sub-[`Command`]s, because they can contain their own arguments,
    /// subcommands, version, usage, etc. They also function just like [`Command`]s, in that they get
    /// their own auto generated help, version, and usage.
    ///
    /// A subcommand's [`Command::name`] will be used for:
    /// - The argument the user passes in
    /// - Programmatically looking up the subcommand
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("config")
    ///         .about("Controls configuration features")
    ///         .arg(arg!("<config> 'Required configuration file to use'")))
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    pub fn subcommand(self, subcmd: impl Into<Command>) -> Self {
        let subcmd = subcmd.into();
        self.subcommand_internal(subcmd)
    }

    fn subcommand_internal(mut self, mut subcmd: Self) -> Self {
        if let Some(current_disp_ord) = self.current_disp_ord.as_mut() {
            let current = *current_disp_ord;
            subcmd.disp_ord.get_or_insert(current);
            *current_disp_ord = current + 1;
        }
        self.subcommands.push(subcmd);
        self
    }

    /// Adds multiple subcommands to the list of valid possibilities.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// # Command::new("myprog")
    /// .subcommands( [
    ///        Command::new("config").about("Controls configuration functionality")
    ///                                 .arg(Arg::new("config_file")),
    ///        Command::new("debug").about("Controls debug functionality")])
    /// # ;
    /// ```
    /// [`IntoIterator`]: std::iter::IntoIterator
    #[must_use]
    pub fn subcommands(mut self, subcmds: impl IntoIterator<Item = impl Into<Self>>) -> Self {
        for subcmd in subcmds {
            self = self.subcommand(subcmd);
        }
        self
    }

    /// Catch problems earlier in the development cycle.
    ///
    /// Most error states are handled as asserts under the assumption they are programming mistake
    /// and not something to handle at runtime.  Rather than relying on tests (manual or automated)
    /// that exhaustively test your CLI to ensure the asserts are evaluated, this will run those
    /// asserts in a way convenient for running as a test.
    ///
    /// **Note::** This will not help with asserts in [`ArgMatches`], those will need exhaustive
    /// testing of your CLI.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// fn cmd() -> Command {
    ///     Command::new("foo")
    ///         .arg(
    ///             Arg::new("bar").short('b').action(ArgAction::SetTrue)
    ///         )
    /// }
    ///
    /// #[test]
    /// fn verify_app() {
    ///     cmd().debug_assert();
    /// }
    ///
    /// fn main() {
    ///     let m = cmd().get_matches_from(vec!["foo", "-b"]);
    ///     println!("{}", *m.get_one::<bool>("bar").expect("defaulted by clap"));
    /// }
    /// ```
    pub fn debug_assert(mut self) {
        self.build();
    }

    /// Custom error message for post-parsing validation
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("myprog");
    /// let err = cmd.error(ErrorKind::InvalidValue, "Some failure case");
    /// ```
    pub fn error(&mut self, kind: ErrorKind, message: impl std::fmt::Display) -> Error {
        Error::raw(kind, message).format(self)
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::try_get_matches_from_mut`]: Command::try_get_matches_from_mut()
    #[inline]
    pub fn get_matches(self) -> ArgMatches {
        self.get_matches_from(&mut env::args_os())
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// Like [`Command::get_matches`] but doesn't consume the `Command`.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let mut cmd = Command::new("myprog")
    ///     // Args and options go here...
    ///     ;
    /// let matches = cmd.get_matches_mut();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::get_matches`]: Command::get_matches()
    pub fn get_matches_mut(&mut self) -> ArgMatches {
        self.try_get_matches_from_mut(&mut env::args_os())
            .unwrap_or_else(|e| e.exit())
    }

    /// Parse [`env::args_os`], returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a
    /// [`ErrorKind::DisplayHelp`] or [`ErrorKind::DisplayVersion`] respectively. You must call
    /// [`Error::exit`] or perform a [`std::process::exit`].
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches()
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    #[inline]
    pub fn try_get_matches(self) -> ClapResult<ArgMatches> {
        // Start the parsing
        self.try_get_matches_from(&mut env::args_os())
    }

    /// Parse the specified arguments, exiting on failure.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches_from(arg_vec);
    /// ```
    /// [`Command::get_matches`]: Command::get_matches()
    /// [`clap::Result`]: Result
    /// [`Vec`]: std::vec::Vec
    pub fn get_matches_from<I, T>(mut self, itr: I) -> ArgMatches
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr).unwrap_or_else(|e| {
            drop(self);
            e.exit()
        })
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches_from(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::get_matches_from`]: Command::get_matches_from()
    /// [`Command::try_get_matches`]: Command::try_get_matches()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Error`]: crate::Error
    /// [`Error::exit`]: crate::Error::exit()
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    /// [`clap::Result`]: Result
    pub fn try_get_matches_from<I, T>(mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr)
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// Like [`Command::try_get_matches_from`] but doesn't consume the `Command`.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let mut cmd = Command::new("myprog");
    ///     // Args and options go here...
    /// let matches = cmd.try_get_matches_from_mut(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::try_get_matches_from`]: Command::try_get_matches_from()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    pub fn try_get_matches_from_mut<I, T>(&mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut raw_args = clap_lex::RawArgs::new(itr.into_iter());
        let mut cursor = raw_args.cursor();

        if self.settings.is_set(AppSettings::Multicall) {
            if let Some(argv0) = raw_args.next_os(&mut cursor) {
                let argv0 = Path::new(&argv0);
                if let Some(command) = argv0.file_stem().and_then(|f| f.to_str()) {
                    // Stop borrowing command so we can get another mut ref to it.
                    let command = command.to_owned();
                    debug!(
                        "Command::try_get_matches_from_mut: Parsed command {} from argv",
                        command
                    );

                    debug!("Command::try_get_matches_from_mut: Reinserting command into arguments so subcommand parser matches it");
                    raw_args.insert(&cursor, [&command]);
                    debug!("Command::try_get_matches_from_mut: Clearing name and bin_name so that displayed command name starts with applet name");
                    self.name = "".into();
                    self.bin_name = None;
                    return self._do_parse(&mut raw_args, cursor);
                }
            }
        };

        // Get the name of the program (argument 1 of env::args()) and determine the
        // actual file
        // that was used to execute the program. This is because a program called
        // ./target/release/my_prog -a
        // will have two arguments, './target/release/my_prog', '-a' but we don't want
        // to display
        // the full path when displaying help messages and such
        if !self.settings.is_set(AppSettings::NoBinaryName) {
            if let Some(name) = raw_args.next_os(&mut cursor) {
                let p = Path::new(name);

                if let Some(f) = p.file_name() {
                    if let Some(s) = f.to_str() {
                        if self.bin_name.is_none() {
                            self.bin_name = Some(s.to_owned());
                        }
                    }
                }
            }
        }

        self._do_parse(&mut raw_args, cursor)
    }

    /// Prints the short help message (`-h`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    pub fn print_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Prints the long help message (`--help`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_long_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    /// [`BufWriter`]: std::io::BufWriter
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn print_long_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Render the short help message (`-h`) to a [`StyledStr`]
    ///
    /// See also [`Command::render_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        styled
    }

    /// Render the long help message (`--help`) to a [`StyledStr`].
    ///
    /// See also [`Command::render_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_long_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_long_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        styled
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_help`")
    )]
    pub fn write_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_long_help`")
    )]
    pub fn write_long_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    /// Version message rendered as if the user ran `-V`.
    ///
    /// See also [`Command::render_long_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_version(&self) -> String {
        self._render_version(false)
    }

    /// Version message rendered as if the user ran `--version`.
    ///
    /// See also [`Command::render_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_long_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_long_version(&self) -> String {
        self._render_version(true)
    }

    /// Usage statement
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// println!("{}", cmd.render_usage());
    /// ```
    pub fn render_usage(&mut self) -> StyledStr {
        self.render_usage_().unwrap_or_default()
    }

    pub(crate) fn render_usage_(&mut self) -> Option<StyledStr> {
        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing incase we run into a subcommand
        self._build_self(false);

        Usage::new(self).create_usage_with_title(&[])
    }
}

/// # Application-wide Settings
///
/// These settings will apply to the top-level command and all subcommands, by default.  Some
/// settings can be overridden in subcommands.
impl Command {
    /// Specifies that the parser should not assume the first argument passed is the binary name.
    ///
    /// This is normally the case when using a "daemon" style mode.  For shells / REPLs, see
    /// [`Command::multicall`][Command::multicall].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let m = Command::new("myprog")
    ///     .no_binary_name(true)
    ///     .arg(arg!(<cmd> ... "commands to run"))
    ///     .get_matches_from(vec!["command", "set"]);
    ///
    /// let cmds: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
    /// assert_eq!(cmds, ["command", "set"]);
    /// ```
    /// [`try_get_matches_from_mut`]: crate::Command::try_get_matches_from_mut()
    #[inline]
    pub fn no_binary_name(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NoBinaryName)
        } else {
            self.unset_global_setting(AppSettings::NoBinaryName)
        }
    }

    /// Try not to fail on parse errors, like missing option values.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let cmd = Command::new("cmd")
    ///   .ignore_errors(true)
    ///   .arg(arg!(-c --config <FILE> "Sets a custom config file"))
    ///   .arg(arg!(-x --stuff <FILE> "Sets a custom stuff file"))
    ///   .arg(arg!(f: -f "Flag"));
    ///
    /// let r = cmd.try_get_matches_from(vec!["cmd", "-c", "file", "-f", "-x"]);
    ///
    /// assert!(r.is_ok(), "unexpected error: {:?}", r);
    /// let m = r.unwrap();
    /// assert_eq!(m.get_one::<String>("config").unwrap(), "file");
    /// assert!(*m.get_one::<bool>("f").expect("defaulted"));
    /// assert_eq!(m.get_one::<String>("stuff"), None);
    /// ```
    #[inline]
    pub fn ignore_errors(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::IgnoreErrors)
        } else {
            self.unset_global_setting(AppSettings::IgnoreErrors)
        }
    }

    /// Replace prior occurrences of arguments rather than error
    ///
    /// For any argument that would conflict with itself by default (e.g.
    /// [`ArgAction::Set`][ArgAction::Set], it will now override itself.
    ///
    /// This is the equivalent to saying the `foo` arg using [`Arg::overrides_with("foo")`] for all
    /// defined arguments.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [`Arg::overrides_with("foo")`]: crate::Arg::overrides_with()
    #[inline]
    pub fn args_override_self(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::AllArgsOverrideSelf)
        } else {
            self.unset_global_setting(AppSettings::AllArgsOverrideSelf)
        }
    }

    /// Disables the automatic delimiting of values after `--` or when [`Command::trailing_var_arg`]
    /// was used.
    ///
    /// **NOTE:** The same thing can be done manually by setting the final positional argument to
    /// [`Arg::value_delimiter(None)`]. Using this setting is safer, because it's easier to locate
    /// when making changes.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .dont_delimit_trailing_values(true)
    ///     .get_matches();
    /// ```
    ///
    /// [`Arg::value_delimiter(None)`]: crate::Arg::value_delimiter()
    #[inline]
    pub fn dont_delimit_trailing_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DontDelimitTrailingValues)
        } else {
            self.unset_global_setting(AppSettings::DontDelimitTrailingValues)
        }
    }

    /// Sets when to color output.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// **NOTE:** Default behaviour is [`ColorChoice::Auto`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, ColorChoice};
    /// Command::new("myprog")
    ///     .color(ColorChoice::Never)
    ///     .get_matches();
    /// ```
    /// [`ColorChoice::Auto`]: crate::ColorChoice::Auto
    #[cfg(feature = "color")]
    #[inline]
    #[must_use]
    pub fn color(self, color: ColorChoice) -> Self {
        let cmd = self
            .unset_global_setting(AppSettings::ColorAuto)
            .unset_global_setting(AppSettings::ColorAlways)
            .unset_global_setting(AppSettings::ColorNever);
        match color {
            ColorChoice::Auto => cmd.global_setting(AppSettings::ColorAuto),
            ColorChoice::Always => cmd.global_setting(AppSettings::ColorAlways),
            ColorChoice::Never => cmd.global_setting(AppSettings::ColorNever),
        }
    }

    /// Sets the terminal width at which to wrap help messages.
    ///
    /// Using `0` will ignore terminal widths and use source formatting.
    ///
    /// Defaults to current terminal width when `wrap_help` feature flag is enabled.  If the flag
    /// is disabled or it cannot be determined, the default is 100.
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .term_width(80)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn term_width(mut self, width: usize) -> Self {
        self.term_w = Some(width);
        self
    }

    /// Limit the line length for wrapping help when using the current terminal's width.
    ///
    /// This only applies when [`term_width`][Command::term_width] is unset so that the current
    /// terminal's width will be used.  See [`Command::term_width`] for more details.
    ///
    /// Using `0` will ignore terminal widths and use source formatting (default).
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .max_term_width(100)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn max_term_width(mut self, w: usize) -> Self {
        self.max_w = Some(w);
        self
    }

    /// Disables `-V` and `--version` flag.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_version_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-V"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_version_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableVersionFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableVersionFlag)
        }
    }

    /// Specifies to use the version of the current command for all [`subcommands`].
    ///
    /// Defaults to `false`; subcommands have independent version strings from their parents.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .version("v1.1")
    ///     .propagate_version(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches();
    /// // running `$ myprog test --version` will display
    /// // "myprog-test v1.1"
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    #[inline]
    pub fn propagate_version(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::PropagateVersion)
        } else {
            self.unset_global_setting(AppSettings::PropagateVersion)
        }
    }

    /// Places the help string for all arguments and subcommands on the line after them.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .next_line_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn next_line_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NextLineHelp)
        } else {
            self.unset_global_setting(AppSettings::NextLineHelp)
        }
    }

    /// Disables `-h` and `--help` flag.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-h"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_help_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpFlag)
        }
    }

    /// Disables the `help` [`subcommand`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_subcommand(true)
    ///     // Normally, creating a subcommand causes a `help` subcommand to automatically
    ///     // be generated as well
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "help"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::InvalidSubcommand);
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn disable_help_subcommand(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpSubcommand)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpSubcommand)
        }
    }

    /// Disables colorized help messages.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .disable_colored_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn disable_colored_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableColoredHelp)
        } else {
            self.unset_global_setting(AppSettings::DisableColoredHelp)
        }
    }

    /// Panic if help descriptions are omitted.
    ///
    /// **NOTE:** When deriving [`Parser`][crate::Parser], you could instead check this at
    /// compile-time with `#![deny(missing_docs)]`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo").help("It does foo stuff")
    ///         // As required via `help_expected`, a help message was supplied
    ///      )
    /// #    .get_matches();
    /// ```
    ///
    /// # Panics
    ///
    /// ```rust,no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo")
    ///         // Someone forgot to put .about("...") here
    ///         // Since the setting `help_expected` is activated, this will lead to
    ///         // a panic (if you are in debug mode)
    ///     )
    /// #   .get_matches();
    ///```
    #[inline]
    pub fn help_expected(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HelpExpected)
        } else {
            self.unset_global_setting(AppSettings::HelpExpected)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn dont_collapse_args_in_usage(self, _yes: bool) -> Self {
        self
    }

    /// Tells `clap` *not* to print possible values when displaying help information.
    ///
    /// This can be useful if there are many values, or they are explained elsewhere.
    ///
    /// To set this per argument, see
    /// [`Arg::hide_possible_values`][crate::Arg::hide_possible_values].
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    #[inline]
    pub fn hide_possible_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HidePossibleValues)
        } else {
            self.unset_global_setting(AppSettings::HidePossibleValues)
        }
    }

    /// Allow partial matches of long arguments or their [aliases].
    ///
    /// For example, to match an argument named `--test`, one could use `--t`, `--te`, `--tes`, and
    /// `--test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match
    /// `--te` to `--test` there could not also be another argument or alias `--temp` because both
    /// start with `--te`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_long_args(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferLongArgs)
        } else {
            self.unset_global_setting(AppSettings::InferLongArgs)
        }
    }

    /// Allow partial matches of [subcommand] names and their [aliases].
    ///
    /// For example, to match a subcommand named `test`, one could use `t`, `te`, `tes`, and
    /// `test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match `te`
    /// to `test` there could not also be a subcommand or alias `temp` because both start with `te`
    ///
    /// **CAUTION:** This setting can interfere with [positional/free arguments], take care when
    /// designing CLIs which allow inferred subcommands and have potential positional/free
    /// arguments whose values could start with the same characters as subcommands. If this is the
    /// case, it's recommended to use settings such as [`Command::args_conflicts_with_subcommands`] in
    /// conjunction with this setting.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("prog")
    ///     .infer_subcommands(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches_from(vec![
    ///         "prog", "te"
    ///     ]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    ///
    /// [subcommand]: crate::Command::subcommand()
    /// [positional/free arguments]: crate::Arg::index()
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_subcommands(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferSubcommands)
        } else {
            self.unset_global_setting(AppSettings::InferSubcommands)
        }
    }
}

/// # Command-specific Settings
///
/// These apply only to the current command and are not inherited by subcommands.
impl Command {
    /// (Re)Sets the program's name.
    ///
    /// See [`Command::new`] for more details.
    ///
    /// # Examples
    ///
    /// ```ignore
    /// let cmd = clap::command!()
    ///     .name("foo");
    ///
    /// // continued logic goes here, such as `cmd.get_matches()` etc.
    /// ```
    #[must_use]
    pub fn name(mut self, name: impl Into<Str>) -> Self {
        self.name = name.into();
        self
    }

    /// Overrides the runtime-determined name of the binary for help and error messages.
    ///
    /// This should only be used when absolutely necessary, such as when the binary name for your
    /// application is misleading, or perhaps *not* how the user should invoke your program.
    ///
    /// **Pro-tip:** When building things such as third party `cargo`
    /// subcommands, this setting **should** be used!
    ///
    /// **NOTE:** This *does not* change or set the name of the binary file on
    /// disk. It only changes what clap thinks the name is for the purposes of
    /// error or help messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .bin_name("my_binary")
    /// # ;
    /// ```
    #[must_use]
    pub fn bin_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.bin_name = name.into_resettable().into_option();
        self
    }

    /// Overrides the runtime-determined display name of the program for help and error messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .display_name("my_program")
    /// # ;
    /// ```
    #[must_use]
    pub fn display_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.display_name = name.into_resettable().into_option();
        self
    }

    /// Sets the author(s) for the help message.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_authors!`] to
    /// automatically set your application's author(s) to the same thing as your
    /// crate at compile time.
    ///
    /// **NOTE:** A custom [`help_template`][Command::help_template] is needed for author to show
    /// up.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///      .author("Me, me@mymain.com")
    /// # ;
    /// ```
    #[must_use]
    pub fn author(mut self, author: impl IntoResettable<Str>) -> Self {
        self.author = author.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the short help (`-h`).
    ///
    /// If [`Command::long_about`] is not specified, this message will be displayed for `--help`.
    ///
    /// **NOTE:** Only `Command::about` (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// See also [`crate_description!`](crate::crate_description!).
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .about("Does really amazing things for great people")
    /// # ;
    /// ```
    #[must_use]
    pub fn about(mut self, about: impl IntoResettable<StyledStr>) -> Self {
        self.about = about.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the long help (`--help`).
    ///
    /// If [`Command::about`] is not specified, this message will be displayed for `-h`.
    ///
    /// **NOTE:** Only [`Command::about`] (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_about(
    /// "Does really amazing things to great people. Now let's talk a little
    ///  more in depth about how this subcommand really works. It may take about
    ///  a few lines of text, but that's ok!")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    #[must_use]
    pub fn long_about(mut self, long_about: impl IntoResettable<StyledStr>) -> Self {
        self.long_about = long_about.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated short help (`-h`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_help("Does really amazing things for great people... but be careful with -R!")
    /// # ;
    /// ```
    ///
    #[must_use]
    pub fn after_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated long help (`--help`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_long_help("Does really amazing things to great people... but be careful with -R, \
    ///                      like, for real, be careful with this!")
    /// # ;
    /// ```
    #[must_use]
    pub fn after_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_long_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated short help (`-h`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_help("Some info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated long help (`--help`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_long_help("Some verbose and long info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_long_help = help.into_resettable().into_option();
        self
    }

    /// Sets the version for the short version (`-V`) and help messages.
    ///
    /// If [`Command::long_version`] is not specified, this message will be displayed for `--version`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("v0.1.24")
    /// # ;
    /// ```
    #[must_use]
    pub fn version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.version = ver.into_resettable().into_option();
        self
    }

    /// Sets the version for the long version (`--version`) and help messages.
    ///
    /// If [`Command::version`] is not specified, this message will be displayed for `-V`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_version(
    /// "v0.1.24
    ///  commit: abcdef89726d
    ///  revision: 123
    ///  release: 2
    ///  binary: myprog")
    /// # ;
    /// ```
    #[must_use]
    pub fn long_version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.long_version = ver.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated usage string for help and error messages.
    ///
    /// **NOTE:** Using this setting disables `clap`s "context-aware" usage
    /// strings. After this setting is set, this will be *the only* usage string
    /// displayed to the user!
    ///
    /// **NOTE:** Multiple usage lines may be present in the usage argument, but
    /// some rules need to be followed to ensure the usage lines are formatted
    /// correctly by the default help formatter:
    ///
    /// - Do not indent the first usage line.
    /// - Indent all subsequent usage lines with seven spaces.
    /// - The last line must not end with a newline.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage("myapp [-clDas] <some_file>")
    /// # ;
    /// ```
    ///
    /// Or for multiple usage lines:
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage(
    ///         "myapp -X [-a] [-b] <file>\n       \
    ///          myapp -Y [-c] <file1> <file2>\n       \
    ///          myapp -Z [-d|-e]"
    ///     )
    /// # ;
    /// ```
    ///
    /// [`ArgMatches::usage`]: ArgMatches::usage()
    #[must_use]
    pub fn override_usage(mut self, usage: impl IntoResettable<StyledStr>) -> Self {
        self.usage_str = usage.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated help message (both `-h` and `--help`).
    ///
    /// This should only be used when the auto-generated message does not suffice.
    ///
    /// **NOTE:** This **only** replaces the help message for the current
    /// command, meaning if you are using subcommands, those help messages will
    /// still be auto-generated unless you specify a [`Command::override_help`] for
    /// them as well.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .override_help("myapp v1.0\n\
    ///            Does awesome things\n\
    ///            (C) me@mail.com\n\n\
    ///
    ///            Usage: myapp <opts> <command>\n\n\
    ///
    ///            Options:\n\
    ///            -h, --help       Display this message\n\
    ///            -V, --version    Display version info\n\
    ///            -s <stuff>       Do something with stuff\n\
    ///            -v               Be verbose\n\n\
    ///
    ///            Commands:\n\
    ///            help             Print this message\n\
    ///            work             Do some work")
    /// # ;
    /// ```
    #[must_use]
    pub fn override_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.help_str = help.into_resettable().into_option();
        self
    }

    /// Sets the help template to be used, overriding the default format.
    ///
    /// **NOTE:** The template system is by design very simple. Therefore, the
    /// tags have to be written in the lowercase and without spacing.
    ///
    /// Tags are given inside curly brackets.
    ///
    /// Valid tags are:
    ///
    ///   * `{name}`                - Display name for the (sub-)command.
    ///   * `{bin}`                 - Binary name.
    ///   * `{version}`             - Version number.
    ///   * `{author}`              - Author information.
    ///   * `{author-with-newline}` - Author followed by `\n`.
    ///   * `{author-section}`      - Author preceded and followed by `\n`.
    ///   * `{about}`               - General description (from [`Command::about`] or
    ///                               [`Command::long_about`]).
    ///   * `{about-with-newline}`  - About followed by `\n`.
    ///   * `{about-section}`       - About preceded and followed by '\n'.
    ///   * `{usage-heading}`       - Automatically generated usage heading.
    ///   * `{usage}`               - Automatically generated or given usage string.
    ///   * `{all-args}`            - Help for all arguments (options, flags, positional
    ///                               arguments, and subcommands) including titles.
    ///   * `{options}`             - Help for options.
    ///   * `{positionals}`         - Help for positional arguments.
    ///   * `{subcommands}`         - Help for subcommands.
    ///   * `{tag}`                 - Standard tab sized used within clap
    ///   * `{after-help}`          - Help from [`Command::after_help`] or [`Command::after_long_help`].
    ///   * `{before-help}`         - Help from [`Command::before_help`] or [`Command::before_long_help`].
    ///
    /// # Examples
    ///
    /// For a very brief help:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("{bin} ({version}) - {usage}")
    /// # ;
    /// ```
    ///
    /// For showing more application context:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("\
    /// {before-help}{name} {version}
    /// {author-with-newline}{about-with-newline}
    /// {usage-heading} {usage}
    ///
    /// {all-args}{after-help}
    /// ")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    /// [`Command::long_about`]: Command::long_about()
    /// [`Command::after_help`]: Command::after_help()
    /// [`Command::after_long_help`]: Command::after_long_help()
    /// [`Command::before_help`]: Command::before_help()
    /// [`Command::before_long_help`]: Command::before_long_help()
    #[must_use]
    #[cfg(feature = "help")]
    pub fn help_template(mut self, s: impl IntoResettable<StyledStr>) -> Self {
        self.template = s.into_resettable().into_option();
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.insert(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.remove(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.set(setting);
        self.g_settings.set(setting);
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.unset(setting);
        self.g_settings.unset(setting);
        self
    }

    /// Set the default section heading for future args.
    ///
    /// This will be used for any arg that hasn't had [`Arg::help_heading`] called.
    ///
    /// This is useful if the default `Options` or `Arguments` headings are
    /// not specific enough for one's use case.
    ///
    /// For subcommands, see [`Command::subcommand_help_heading`]
    ///
    /// [`Command::arg`]: Command::arg()
    /// [`Arg::help_heading`]: crate::Arg::help_heading()
    #[inline]
    #[must_use]
    pub fn next_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.current_help_heading = heading.into_resettable().into_option();
        self
    }

    /// Change the starting value for assigning future display orders for ags.
    ///
    /// This will be used for any arg that hasn't had [`Arg::display_order`] called.
    #[inline]
    #[must_use]
    pub fn next_display_order(mut self, disp_ord: impl IntoResettable<usize>) -> Self {
        self.current_disp_ord = disp_ord.into_resettable().into_option();
        self
    }

    /// Replaces an argument or subcommand used on the CLI at runtime with other arguments or subcommands.
    ///
    /// **Note:** This is gated behind [`unstable-replace`](https://github.com/clap-rs/clap/issues/2836)
    ///
    /// When this method is used, `name` is removed from the CLI, and `target`
    /// is inserted in its place. Parsing continues as if the user typed
    /// `target` instead of `name`.
    ///
    /// This can be used to create "shortcuts" for subcommands, or if a
    /// particular argument has the semantic meaning of several other specific
    /// arguments and values.
    ///
    /// # Examples
    ///
    /// We'll start with the "subcommand short" example. In this example, let's
    /// assume we have a program with a subcommand `module` which can be invoked
    /// via `cmd module`. Now let's also assume `module` also has a subcommand
    /// called `install` which can be invoked `cmd module install`. If for some
    /// reason users needed to be able to reach `cmd module install` via the
    /// short-hand `cmd install`, we'd have several options.
    ///
    /// We *could* create another sibling subcommand to `module` called
    /// `install`, but then we would need to manage another subcommand and manually
    /// dispatch to `cmd module install` handling code. This is error prone and
    /// tedious.
    ///
    /// We could instead use [`Command::replace`] so that, when the user types `cmd
    /// install`, `clap` will replace `install` with `module install` which will
    /// end up getting parsed as if the user typed the entire incantation.
    ///
    /// ```rust
    /// # use clap::Command;
    /// let m = Command::new("cmd")
    ///     .subcommand(Command::new("module")
    ///         .subcommand(Command::new("install")))
    ///     .replace("install", &["module", "install"])
    ///     .get_matches_from(vec!["cmd", "install"]);
    ///
    /// assert!(m.subcommand_matches("module").is_some());
    /// assert!(m.subcommand_matches("module").unwrap().subcommand_matches("install").is_some());
    /// ```
    ///
    /// Now let's show an argument example!
    ///
    /// Let's assume we have an application with two flags `--save-context` and
    /// `--save-runtime`. But often users end up needing to do *both* at the
    /// same time. We can add a third flag `--save-all` which semantically means
    /// the same thing as `cmd --save-context --save-runtime`. To implement that,
    /// we have several options.
    ///
    /// We could create this third argument and manually check if that argument
    /// and in our own consumer code handle the fact that both `--save-context`
    /// and `--save-runtime` *should* have been used. But again this is error
    /// prone and tedious. If we had code relying on checking `--save-context`
    /// and we forgot to update that code to *also* check `--save-all` it'd mean
    /// an error!
    ///
    /// Luckily we can use [`Command::replace`] so that when the user types
    /// `--save-all`, `clap` will replace that argument with `--save-context
    /// --save-runtime`, and parsing will continue like normal. Now all our code
    /// that was originally checking for things like `--save-context` doesn't
    /// need to change!
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .replace("--save-all", &["--save-context", "--save-runtime"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// ```
    ///
    /// This can also be used with options, for example if our application with
    /// `--save-*` above also had a `--format=TYPE` option. Let's say it
    /// accepted `txt` or `json` values. However, when `--save-all` is used,
    /// only `--format=json` is allowed, or valid. We could change the example
    /// above to enforce this:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("format")
    ///         .long("format")
    ///         .action(ArgAction::Set)
    ///         .value_parser(["txt", "json"]))
    ///     .replace("--save-all", &["--save-context", "--save-runtime", "--format=json"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// assert_eq!(m.get_one::<String>("format").unwrap(), "json");
    /// ```
    ///
    /// [`Command::replace`]: Command::replace()
    #[inline]
    #[cfg(feature = "unstable-replace")]
    #[must_use]
    pub fn replace(
        mut self,
        name: impl Into<Str>,
        target: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        self.replacers
            .insert(name.into(), target.into_iter().map(Into::into).collect());
        self
    }

    /// Exit gracefully if no arguments are present (e.g. `$ myprog`).
    ///
    /// **NOTE:** [`subcommands`] count as arguments
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command};
    /// Command::new("myprog")
    ///     .arg_required_else_help(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    /// [`Arg::default_value`]: crate::Arg::default_value()
    #[inline]
    pub fn arg_required_else_help(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgRequiredElseHelp)
        } else {
            self.unset_setting(AppSettings::ArgRequiredElseHelp)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_hyphen_values`")
    )]
    pub fn allow_hyphen_values(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowHyphenValues)
        } else {
            self.unset_setting(AppSettings::AllowHyphenValues)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_negative_numbers`")
    )]
    pub fn allow_negative_numbers(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowNegativeNumbers)
        } else {
            self.unset_setting(AppSettings::AllowNegativeNumbers)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::trailing_var_arg`")
    )]
    pub fn trailing_var_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::TrailingVarArg)
        } else {
            self.unset_setting(AppSettings::TrailingVarArg)
        }
    }

    /// Allows one to implement two styles of CLIs where positionals can be used out of order.
    ///
    /// The first example is a CLI where the second to last positional argument is optional, but
    /// the final positional argument is required. Such as `$ prog [optional] <required>` where one
    /// of the two following usages is allowed:
    ///
    /// * `$ prog [optional] <required>`
    /// * `$ prog <required>`
    ///
    /// This would otherwise not be allowed. This is useful when `[optional]` has a default value.
    ///
    /// **Note:** when using this style of "missing positionals" the final positional *must* be
    /// [required] if `--` will not be used to skip to the final positional argument.
    ///
    /// **Note:** This style also only allows a single positional argument to be "skipped" without
    /// the use of `--`. To skip more than one, see the second example.
    ///
    /// The second example is when one wants to skip multiple optional positional arguments, and use
    /// of the `--` operator is OK (but not required if all arguments will be specified anyways).
    ///
    /// For example, imagine a CLI which has three positional arguments `[foo] [bar] [baz]...` where
    /// `baz` accepts multiple values (similar to man `ARGS...` style training arguments).
    ///
    /// With this setting the following invocations are posisble:
    ///
    /// * `$ prog foo bar baz1 baz2 baz3`
    /// * `$ prog foo -- baz1 baz2 baz3`
    /// * `$ prog -- baz1 baz2 baz3`
    ///
    /// # Examples
    ///
    /// Style number one from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1"), None);
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Now the same example, but using a default value for the first optional positional argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1")
    ///         .default_value("something"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1").unwrap(), "something");
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Style number two from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "foo", "bar", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo").unwrap(), "foo");
    /// assert_eq!(m.get_one::<String>("bar").unwrap(), "bar");
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// Now nofice if we don't specify `foo` or `baz` but use the `--` operator.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "--", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo"), None);
    /// assert_eq!(m.get_one::<String>("bar"), None);
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// [required]: crate::Arg::required()
    #[inline]
    pub fn allow_missing_positional(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowMissingPositional)
        } else {
            self.unset_setting(AppSettings::AllowMissingPositional)
        }
    }
}

/// # Subcommand-specific Settings
impl Command {
    /// Sets the short version of the subcommand flag without the preceding `-`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::short`].
    ///
    /// # Examples
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").short_flag('S').arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "-Ss"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    /// [`Arg::short`]: Arg::short()
    #[must_use]
    pub fn short_flag(mut self, short: impl IntoResettable<char>) -> Self {
        self.short_flag = short.into_resettable().into_option();
        self
    }

    /// Sets the long version of the subcommand flag without the preceding `--`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::long`].
    ///
    /// **NOTE:** Any leading `-` characters will be stripped.
    ///
    /// # Examples
    ///
    /// To set `long_flag` use a word containing valid UTF-8 codepoints. If you supply a double leading
    /// `--` such as `--sync` they will be stripped. Hyphens in the middle of the word; however,
    /// will *not* be stripped (i.e. `sync-file` is allowed).
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").long_flag("sync").arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "--sync", "--search"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    ///
    /// [`Arg::long`]: Arg::long()
    #[must_use]
    pub fn long_flag(mut self, long: impl Into<Str>) -> Self {
        self.long_flag = Some(long.into());
        self
    }

    /// Sets a hidden alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name, or this given
    /// alias. This is more efficient and easier than creating multiple hidden subcommands as one
    /// only needs to check for the existence of this command, and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If you're looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_alias`]: Command::visible_alias()
    #[must_use]
    pub fn alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, false));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "hidden" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, false));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "hidden" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, false));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple hidden aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name or any of the
    /// given aliases. This is more efficient, and easier than creating multiple hidden subcommands
    /// as one only needs to check for the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_aliases`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .aliases(["do-stuff", "do-tests", "tests"]))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "do-tests"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_aliases`]: Command::visible_aliases()
    #[must_use]
    pub fn aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), false)));
        self
    }

    /// Add aliases, which function as "hidden" short flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test").short_flag('t')
    ///         .short_flag_aliases(['a', 'b', 'c']))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "-a"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, false));
        }
        self
    }

    /// Add aliases, which function as "hidden" long flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_aliases(["testing", "testall", "test_all"]))
    ///                 .arg(Arg::new("input")
    ///                             .help("the file to add")
    ///                             .required(false))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        for s in names {
            self = self.long_flag_alias(s)
        }
        self
    }

    /// Sets a visible alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or the given alias. This is more efficient and easier
    /// than creating hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, true));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "visible" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::short_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .visible_short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_alias`]: Command::short_flag_alias()
    #[must_use]
    pub fn visible_short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, true));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "visible" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::long_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_alias`]: Command::long_flag_alias()
    #[must_use]
    pub fn visible_long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, true));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple visible aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or any of the given aliases. This is more efficient and easier
    /// than creating multiple hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases, and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_aliases(["do-stuff", "tests"]))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), true)));
        self
    }

    /// Add aliases, which function as *visible* short flag subcommands.
    ///
    /// See [`Command::short_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('b')
    ///                 .visible_short_flag_aliases(['t']))
    ///             .get_matches_from(vec!["myprog", "-t"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_aliases`]: Command::short_flag_aliases()
    #[must_use]
    pub fn visible_short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, true));
        }
        self
    }

    /// Add aliases, which function as *visible* long flag subcommands.
    ///
    /// See [`Command::long_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_aliases(["testing", "testall", "test_all"]))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_aliases`]: Command::long_flag_aliases()
    #[must_use]
    pub fn visible_long_flag_aliases(
        mut self,
        names: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        for s in names {
            self = self.visible_long_flag_alias(s);
        }
        self
    }

    /// Set the placement of this subcommand within the help.
    ///
    /// Subcommands with a lower value will be displayed first in the help message.  Subcommands
    /// with duplicate display orders will be displayed in alphabetical order.
    ///
    /// This is helpful when one would like to emphasize frequently used subcommands, or prioritize
    /// those towards the top of the list.
    ///
    /// **NOTE:** The default is 999 for all subcommands.
    ///
    /// # Examples
    ///
    #[cfg_attr(not(feature = "help"), doc = " ```ignore")]
    #[cfg_attr(feature = "help", doc = " ```")]
    /// # use clap::{Command, };
    /// let m = Command::new("cust-ord")
    ///     .subcommand(Command::new("alpha") // typically subcommands are grouped
    ///                                                // alphabetically by name. Subcommands
    ///                                                // without a display_order have a value of
    ///                                                // 999 and are displayed alphabetically with
    ///                                                // all other 999 subcommands
    ///         .about("Some help and text"))
    ///     .subcommand(Command::new("beta")
    ///         .display_order(1)   // In order to force this subcommand to appear *first*
    ///                             // all we have to do is give it a value lower than 999.
    ///                             // Any other subcommands with a value of 1 will be displayed
    ///                             // alphabetically with this one...then 2 values, then 3, etc.
    ///         .about("I should be first!"))
    ///     .get_matches_from(vec![
    ///         "cust-ord", "--help"
    ///     ]);
    /// ```
    ///
    /// The above example displays the following help message
    ///
    /// ```text
    /// cust-ord
    ///
    /// Usage: cust-ord [OPTIONS]
    ///
    /// Commands:
    ///     beta    I should be first!
    ///     alpha   Some help and text
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[inline]
    #[must_use]
    pub fn display_order(mut self, ord: impl IntoResettable<usize>) -> Self {
        self.disp_ord = ord.into_resettable().into_option();
        self
    }

    /// Specifies that this [`subcommand`] should be hidden from help messages
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(
    ///         Command::new("test").hide(true)
    ///     )
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn hide(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Hidden)
        } else {
            self.unset_setting(AppSettings::Hidden)
        }
    }

    /// If no [`subcommand`] is present at runtime, error and exit gracefully.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_required(true)
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog",
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingSubcommand);
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    pub fn subcommand_required(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandRequired)
        } else {
            self.unset_setting(AppSettings::SubcommandRequired)
        }
    }

    /// Assume unexpected positional arguments are a [`subcommand`].
    ///
    /// Arguments will be stored in the `""` argument in the [`ArgMatches`]
    ///
    /// **NOTE:** Use this setting with caution,
    /// as a truly unexpected argument (i.e. one that is *NOT* an external subcommand)
    /// will **not** cause an error and instead be treated as a potential subcommand.
    /// One should check for such cases manually and inform the user appropriately.
    ///
    /// **NOTE:** A built-in subcommand will be parsed as an external subcommand when escaped with
    /// `--`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    /// [`ArgMatches`]: crate::ArgMatches
    /// [`ErrorKind::UnknownArgument`]: crate::error::ErrorKind::UnknownArgument
    pub fn allow_external_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowExternalSubcommands)
        } else {
            self.unset_setting(AppSettings::AllowExternalSubcommands)
        }
    }

    /// Specifies how to parse external subcommand arguments.
    ///
    /// The default parser is for `OsString`.  This can be used to switch it to `String` or another
    /// type.
    ///
    /// **NOTE:** Setting this requires [`Command::allow_external_subcommands`]
    ///
    /// # Examples
    ///
    #[cfg_attr(not(unix), doc = " ```ignore")]
    #[cfg_attr(unix, doc = " ```")]
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// ```
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .external_subcommand_value_parser(value_parser!(String))
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<String>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn external_subcommand_value_parser(
        mut self,
        parser: impl IntoResettable<super::ValueParser>,
    ) -> Self {
        self.external_value_parser = parser.into_resettable().into_option();
        self
    }

    /// Specifies that use of an argument prevents the use of [`subcommands`].
    ///
    /// By default `clap` allows arguments between subcommands such
    /// as `<cmd> [cmd_args] <subcmd> [subcmd_args] <subsubcmd> [subsubcmd_args]`.
    ///
    /// This setting disables that functionality and says that arguments can
    /// only follow the *final* subcommand. For instance using this setting
    /// makes only the following invocations possible:
    ///
    /// * `<cmd> <subcmd> <subsubcmd> [subsubcmd_args]`
    /// * `<cmd> <subcmd> [subcmd_args]`
    /// * `<cmd> [cmd_args]`
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .args_conflicts_with_subcommands(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn args_conflicts_with_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgsNegateSubcommands)
        } else {
            self.unset_setting(AppSettings::ArgsNegateSubcommands)
        }
    }

    /// Prevent subcommands from being consumed as an arguments value.
    ///
    /// By default, if an option taking multiple values is followed by a subcommand, the
    /// subcommand will be parsed as another value.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   another value
    /// ```
    ///
    /// This setting instructs the parser to stop when encountering a subcommand instead of
    /// greedily consuming arguments.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   subcommand
    /// ```
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let cmd = Command::new("cmd").subcommand(Command::new("sub")).arg(
    ///     Arg::new("arg")
    ///         .long("arg")
    ///         .num_args(1..)
    ///         .action(ArgAction::Set),
    /// );
    ///
    /// let matches = cmd
    ///     .clone()
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3", "sub"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_none());
    ///
    /// let matches = cmd
    ///     .subcommand_precedence_over_arg(true)
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_some());
    /// ```
    pub fn subcommand_precedence_over_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandPrecedenceOverArg)
        } else {
            self.unset_setting(AppSettings::SubcommandPrecedenceOverArg)
        }
    }

    /// Allows [`subcommands`] to override all requirements of the parent command.
    ///
    /// For example, if you had a subcommand or top level application with a required argument
    /// that is only required as long as there is no subcommand present,
    /// using this setting would allow you to set those arguments to [`Arg::required(true)`]
    /// and yet receive no error so long as the user uses a valid subcommand instead.
    ///
    /// **NOTE:** This defaults to false (using subcommand does *not* negate requirements)
    ///
    /// # Examples
    ///
    /// This first example shows that it is an error to not use a required argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog"
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);
    /// # ;
    /// ```
    ///
    /// This next example shows that it is no longer error to not use a required argument if a
    /// valid subcommand is used.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let noerr = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "test"
    ///     ]);
    /// assert!(noerr.is_ok());
    /// # ;
    /// ```
    ///
    /// [`Arg::required(true)`]: crate::Arg::required()
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn subcommand_negates_reqs(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandsNegateReqs)
        } else {
            self.unset_setting(AppSettings::SubcommandsNegateReqs)
        }
    }

    /// Multiple-personality program dispatched on the binary name (`argv[0]`)
    ///
    /// A "multicall" executable is a single executable
    /// that contains a variety of applets,
    /// and decides which applet to run based on the name of the file.
    /// The executable can be called from different names by creating hard links
    /// or symbolic links to it.
    ///
    /// This is desirable for:
    /// - Easy distribution, a single binary that can install hardlinks to access the different
    ///   personalities.
    /// - Minimal binary size by sharing common code (e.g. standard library, clap)
    /// - Custom shells or REPLs where there isn't a single top-level command
    ///
    /// Setting `multicall` will cause
    /// - `argv[0]` to be stripped to the base name and parsed as the first argument, as if
    ///   [`Command::no_binary_name`][Command::no_binary_name] was set.
    /// - Help and errors to report subcommands as if they were the top-level command
    ///
    /// When the subcommand is not present, there are several strategies you may employ, depending
    /// on your needs:
    /// - Let the error percolate up normally
    /// - Print a specialized error message using the
    ///   [`Error::context`][crate::Error::context]
    /// - Print the [help][Command::write_help] but this might be ambiguous
    /// - Disable `multicall` and re-parse it
    /// - Disable `multicall` and re-parse it with a specific subcommand
    ///
    /// When detecting the error condition, the [`ErrorKind`] isn't sufficient as a sub-subcommand
    /// might report the same error.  Enable
    /// [`allow_external_subcommands`][Command::allow_external_subcommands] if you want to specifically
    /// get the unrecognized binary name.
    ///
    /// **NOTE:** Multicall can't be used with [`no_binary_name`] since they interpret
    /// the command name in incompatible ways.
    ///
    /// **NOTE:** The multicall command cannot have arguments.
    ///
    /// **NOTE:** Applets are slightly semantically different from subcommands,
    /// so it's recommended to use [`Command::subcommand_help_heading`] and
    /// [`Command::subcommand_value_name`] to change the descriptive text as above.
    ///
    /// # Examples
    ///
    /// `hostname` is an example of a multicall executable.
    /// Both `hostname` and `dnsdomainname` are provided by the same executable
    /// and which behaviour to use is based on the executable file name.
    ///
    /// This is desirable when the executable has a primary purpose
    /// but there is related functionality that would be convenient to provide
    /// and implement it to be in the same executable.
    ///
    /// The name of the cmd is essentially unused
    /// and may be the same as the name of a subcommand.
    ///
    /// The names of the immediate subcommands of the Command
    /// are matched against the basename of the first argument,
    /// which is conventionally the path of the executable.
    ///
    /// This does not allow the subcommand to be passed as the first non-path argument.
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("hostname")
    ///     .multicall(true)
    ///     .subcommand(Command::new("hostname"))
    ///     .subcommand(Command::new("dnsdomainname"));
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/hostname", "dnsdomainname"]);
    /// assert!(m.is_err());
    /// assert_eq!(m.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// let m = cmd.get_matches_from(&["/usr/bin/dnsdomainname"]);
    /// assert_eq!(m.subcommand_name(), Some("dnsdomainname"));
    /// ```
    ///
    /// Busybox is another common example of a multicall executable
    /// with a subcommmand for each applet that can be run directly,
    /// e.g. with the `cat` applet being run by running `busybox cat`,
    /// or with `cat` as a link to the `busybox` binary.
    ///
    /// This is desirable when the launcher program has additional options
    /// or it is useful to run the applet without installing a symlink
    /// e.g. to test the applet without installing it
    /// or there may already be a command of that name installed.
    ///
    /// To make an applet usable as both a multicall link and a subcommand
    /// the subcommands must be defined both in the top-level Command
    /// and as subcommands of the "main" applet.
    ///
    /// ```rust
    /// # use clap::Command;
    /// fn applet_commands() -> [Command; 2] {
    ///     [Command::new("true"), Command::new("false")]
    /// }
    /// let mut cmd = Command::new("busybox")
    ///     .multicall(true)
    ///     .subcommand(
    ///         Command::new("busybox")
    ///             .subcommand_value_name("APPLET")
    ///             .subcommand_help_heading("APPLETS")
    ///             .subcommands(applet_commands()),
    ///     )
    ///     .subcommands(applet_commands());
    /// // When called from the executable's canonical name
    /// // its applets can be matched as subcommands.
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/busybox", "true"]).unwrap();
    /// assert_eq!(m.subcommand_name(), Some("busybox"));
    /// assert_eq!(m.subcommand().unwrap().1.subcommand_name(), Some("true"));
    /// // When called from a link named after an applet that applet is matched.
    /// let m = cmd.get_matches_from(&["/usr/bin/true"]);
    /// assert_eq!(m.subcommand_name(), Some("true"));
    /// ```
    ///
    /// [`no_binary_name`]: crate::Command::no_binary_name
    /// [`Command::subcommand_value_name`]: crate::Command::subcommand_value_name
    /// [`Command::subcommand_help_heading`]: crate::Command::subcommand_help_heading
    #[inline]
    pub fn multicall(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Multicall)
        } else {
            self.unset_setting(AppSettings::Multicall)
        }
    }

    /// Sets the value name used for subcommands when printing usage and help.
    ///
    /// By default, this is "COMMAND".
    ///
    /// See also [`Command::subcommand_help_heading`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_value_name`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_value_name("THING")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [THING]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_value_name(mut self, value_name: impl IntoResettable<Str>) -> Self {
        self.subcommand_value_name = value_name.into_resettable().into_option();
        self
    }

    /// Sets the help heading used for subcommands when printing usage and help.
    ///
    /// By default, this is "Commands".
    ///
    /// See also [`Command::subcommand_value_name`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_help_heading`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_help_heading("Things")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Things:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.subcommand_heading = heading.into_resettable().into_option();
        self
    }
}

/// # Reflection
impl Command {
    #[inline]
    #[cfg(feature = "usage")]
    pub(crate) fn get_usage_name(&self) -> Option<&str> {
        self.usage_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_display_name(&self) -> Option<&str> {
        self.display_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_bin_name(&self) -> Option<&str> {
        self.bin_name.as_deref()
    }

    /// Set binary name. Uses `&mut self` instead of `self`.
    pub fn set_bin_name(&mut self, name: impl Into<String>) {
        self.bin_name = Some(name.into());
    }

    /// Get the name of the cmd.
    #[inline]
    pub fn get_name(&self) -> &str {
        self.name.as_str()
    }

    #[inline]
    #[cfg(debug_assertions)]
    pub(crate) fn get_name_str(&self) -> &Str {
        &self.name
    }

    /// Get the version of the cmd.
    #[inline]
    pub fn get_version(&self) -> Option<&str> {
        self.version.as_deref()
    }

    /// Get the long version of the cmd.
    #[inline]
    pub fn get_long_version(&self) -> Option<&str> {
        self.long_version.as_deref()
    }

    /// Get the authors of the cmd.
    #[inline]
    pub fn get_author(&self) -> Option<&str> {
        self.author.as_deref()
    }

    /// Get the short flag of the subcommand.
    #[inline]
    pub fn get_short_flag(&self) -> Option<char> {
        self.short_flag
    }

    /// Get the long flag of the subcommand.
    #[inline]
    pub fn get_long_flag(&self) -> Option<&str> {
        self.long_flag.as_deref()
    }

    /// Get the help message specified via [`Command::about`].
    ///
    /// [`Command::about`]: Command::about()
    #[inline]
    pub fn get_about(&self) -> Option<&StyledStr> {
        self.about.as_ref()
    }

    /// Get the help message specified via [`Command::long_about`].
    ///
    /// [`Command::long_about`]: Command::long_about()
    #[inline]
    pub fn get_long_about(&self) -> Option<&StyledStr> {
        self.long_about.as_ref()
    }

    /// Get the custom section heading specified via [`Command::next_help_heading`].
    ///
    /// [`Command::help_heading`]: Command::help_heading()
    #[inline]
    pub fn get_next_help_heading(&self) -> Option<&str> {
        self.current_help_heading.as_deref()
    }

    /// Iterate through the *visible* aliases for this subcommand.
    #[inline]
    pub fn get_visible_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the *visible* short aliases for this subcommand.
    #[inline]
    pub fn get_visible_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0)
    }

    /// Iterate through the *visible* long aliases for this subcommand.
    #[inline]
    pub fn get_visible_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases.iter().map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the short aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases.iter().map(|a| a.0)
    }

    /// Iterate through the set of *all* the long aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases.iter().map(|a| a.0.as_str())
    }

    #[inline]
    pub(crate) fn is_set(&self, s: AppSettings) -> bool {
        self.settings.is_set(s) || self.g_settings.is_set(s)
    }

    /// Should we color the output?
    pub fn get_color(&self) -> ColorChoice {
        debug!("Command::color: Color setting...");

        if cfg!(feature = "color") {
            if self.is_set(AppSettings::ColorNever) {
                debug!("Never");
                ColorChoice::Never
            } else if self.is_set(AppSettings::ColorAlways) {
                debug!("Always");
                ColorChoice::Always
            } else {
                debug!("Auto");
                ColorChoice::Auto
            }
        } else {
            ColorChoice::Never
        }
    }

    /// Iterate through the set of subcommands, getting a reference to each.
    #[inline]
    pub fn get_subcommands(&self) -> impl Iterator<Item = &Command> {
        self.subcommands.iter()
    }

    /// Iterate through the set of subcommands, getting a mutable reference to each.
    #[inline]
    pub fn get_subcommands_mut(&mut self) -> impl Iterator<Item = &mut Command> {
        self.subcommands.iter_mut()
    }

    /// Returns `true` if this `Command` has subcommands.
    #[inline]
    pub fn has_subcommands(&self) -> bool {
        !self.subcommands.is_empty()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_subcommand_help_heading(&self) -> Option<&str> {
        self.subcommand_heading.as_deref()
    }

    /// Returns the subcommand value name.
    #[inline]
    pub fn get_subcommand_value_name(&self) -> Option<&str> {
        self.subcommand_value_name.as_deref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_help(&self) -> Option<&StyledStr> {
        self.before_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_long_help(&self) -> Option<&StyledStr> {
        self.before_long_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_help(&self) -> Option<&StyledStr> {
        self.after_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_long_help(&self) -> Option<&StyledStr> {
        self.after_long_help.as_ref()
    }

    /// Find subcommand such that its name or one of aliases equals `name`.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand(&self, name: impl AsRef<std::ffi::OsStr>) -> Option<&Command> {
        let name = name.as_ref();
        self.get_subcommands().find(|s| s.aliases_to(name))
    }

    /// Find subcommand such that its name or one of aliases equals `name`, returning
    /// a mutable reference to the subcommand.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand_mut(
        &mut self,
        name: impl AsRef<std::ffi::OsStr>,
    ) -> Option<&mut Command> {
        let name = name.as_ref();
        self.get_subcommands_mut().find(|s| s.aliases_to(name))
    }

    /// Iterate through the set of groups.
    #[inline]
    pub fn get_groups(&self) -> impl Iterator<Item = &ArgGroup> {
        self.groups.iter()
    }

    /// Iterate through the set of arguments.
    #[inline]
    pub fn get_arguments(&self) -> impl Iterator<Item = &Arg> {
        self.args.args()
    }

    /// Iterate through the *positionals* arguments.
    #[inline]
    pub fn get_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| a.is_positional())
    }

    /// Iterate through the *options*.
    pub fn get_opts(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments()
            .filter(|a| a.is_takes_value_set() && !a.is_positional())
    }

    /// Get a list of all arguments the given argument conflicts with.
    ///
    /// If the provided argument is declared as global, the conflicts will be determined
    /// based on the propagation rules of global arguments.
    ///
    /// ### Panics
    ///
    /// If the given arg contains a conflict with an argument that is unknown to
    /// this `Command`.
    pub fn get_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        if arg.is_global_set() {
            self.get_global_arg_conflicts_with(arg)
        } else {
            let mut result = Vec::new();
            for id in arg.blacklist.iter() {
                if let Some(arg) = self.find(id) {
                    result.push(arg);
                } else if let Some(group) = self.find_group(id) {
                    result.extend(
                        self.unroll_args_in_group(&group.id)
                            .iter()
                            .map(|id| self.find(id).expect(INTERNAL_ERROR_MSG)),
                    );
                } else {
                    panic!("Command::get_arg_conflicts_with: The passed arg conflicts with an arg unknown to the cmd");
                }
            }
            result
        }
    }

    // Get a unique list of all arguments of all commands and continuous subcommands the given argument conflicts with.
    //
    // This behavior follows the propagation rules of global arguments.
    // It is useful for finding conflicts for arguments declared as global.
    //
    // ### Panics
    //
    // If the given arg contains a conflict with an argument that is unknown to
    // this `Command`.
    fn get_global_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        arg.blacklist
            .iter()
            .map(|id| {
                self.args
                    .args()
                    .chain(
                        self.get_subcommands_containing(arg)
                            .iter()
                            .flat_map(|x| x.args.args()),
                    )
                    .find(|arg| arg.get_id() == id)
                    .expect(
                        "Command::get_arg_conflicts_with: \
                    The passed arg conflicts with an arg unknown to the cmd",
                    )
            })
            .collect()
    }

    // Get a list of subcommands which contain the provided Argument
    //
    // This command will only include subcommands in its list for which the subcommands
    // parent also contains the Argument.
    //
    // This search follows the propagation rules of global arguments.
    // It is useful to finding subcommands, that have inherited a global argument.
    //
    // **NOTE:** In this case only Sucommand_1 will be included
    //   Subcommand_1 (contains Arg)
    //     Subcommand_1.1 (doesn't contain Arg)
    //       Subcommand_1.1.1 (contains Arg)
    //
    fn get_subcommands_containing(&self, arg: &Arg) -> Vec<&Self> {
        let mut vec = std::vec::Vec::new();
        for idx in 0..self.subcommands.len() {
            if self.subcommands[idx]
                .args
                .args()
                .any(|ar| ar.get_id() == arg.get_id())
            {
                vec.push(&self.subcommands[idx]);
                vec.append(&mut self.subcommands[idx].get_subcommands_containing(arg));
            }
        }
        vec
    }

    /// Report whether [`Command::no_binary_name`] is set
    pub fn is_no_binary_name_set(&self) -> bool {
        self.is_set(AppSettings::NoBinaryName)
    }

    /// Report whether [`Command::ignore_errors`] is set
    pub(crate) fn is_ignore_errors_set(&self) -> bool {
        self.is_set(AppSettings::IgnoreErrors)
    }

    /// Report whether [`Command::dont_delimit_trailing_values`] is set
    pub fn is_dont_delimit_trailing_values_set(&self) -> bool {
        self.is_set(AppSettings::DontDelimitTrailingValues)
    }

    /// Report whether [`Command::disable_version_flag`] is set
    pub fn is_disable_version_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableVersionFlag)
            || (self.version.is_none() && self.long_version.is_none())
    }

    /// Report whether [`Command::propagate_version`] is set
    pub fn is_propagate_version_set(&self) -> bool {
        self.is_set(AppSettings::PropagateVersion)
    }

    /// Report whether [`Command::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(AppSettings::NextLineHelp)
    }

    /// Report whether [`Command::disable_help_flag`] is set
    pub fn is_disable_help_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpFlag)
    }

    /// Report whether [`Command::disable_help_subcommand`] is set
    pub fn is_disable_help_subcommand_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpSubcommand)
    }

    /// Report whether [`Command::disable_colored_help`] is set
    pub fn is_disable_colored_help_set(&self) -> bool {
        self.is_set(AppSettings::DisableColoredHelp)
    }

    /// Report whether [`Command::help_expected`] is set
    #[cfg(debug_assertions)]
    pub(crate) fn is_help_expected_set(&self) -> bool {
        self.is_set(AppSettings::HelpExpected)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn is_dont_collapse_args_in_usage_set(&self) -> bool {
        true
    }

    /// Report whether [`Command::infer_long_args`] is set
    pub(crate) fn is_infer_long_args_set(&self) -> bool {
        self.is_set(AppSettings::InferLongArgs)
    }

    /// Report whether [`Command::infer_subcommands`] is set
    pub(crate) fn is_infer_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::InferSubcommands)
    }

    /// Report whether [`Command::arg_required_else_help`] is set
    pub fn is_arg_required_else_help_set(&self) -> bool {
        self.is_set(AppSettings::ArgRequiredElseHelp)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_hyphen_values_set`"
        )
    )]
    pub(crate) fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(AppSettings::AllowHyphenValues)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_negative_numbers_set`"
        )
    )]
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(AppSettings::AllowNegativeNumbers)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::is_trailing_var_arg_set`")
    )]
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(AppSettings::TrailingVarArg)
    }

    /// Report whether [`Command::allow_missing_positional`] is set
    pub fn is_allow_missing_positional_set(&self) -> bool {
        self.is_set(AppSettings::AllowMissingPositional)
    }

    /// Report whether [`Command::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(AppSettings::Hidden)
    }

    /// Report whether [`Command::subcommand_required`] is set
    pub fn is_subcommand_required_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandRequired)
    }

    /// Report whether [`Command::allow_external_subcommands`] is set
    pub fn is_allow_external_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::AllowExternalSubcommands)
    }

    /// Configured parser for values passed to an external subcommand
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .external_subcommand_value_parser(clap::value_parser!(String));
    /// let value_parser = cmd.get_external_subcommand_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_external_subcommand_value_parser(&self) -> Option<&super::ValueParser> {
        if !self.is_allow_external_subcommands_set() {
            None
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::os_string();
            Some(self.external_value_parser.as_ref().unwrap_or(&DEFAULT))
        }
    }

    /// Report whether [`Command::args_conflicts_with_subcommands`] is set
    pub fn is_args_conflicts_with_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::ArgsNegateSubcommands)
    }

    #[doc(hidden)]
    pub fn is_args_override_self(&self) -> bool {
        self.is_set(AppSettings::AllArgsOverrideSelf)
    }

    /// Report whether [`Command::subcommand_precedence_over_arg`] is set
    pub fn is_subcommand_precedence_over_arg_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandPrecedenceOverArg)
    }

    /// Report whether [`Command::subcommand_negates_reqs`] is set
    pub fn is_subcommand_negates_reqs_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandsNegateReqs)
    }

    /// Report whether [`Command::multicall`] is set
    pub fn is_multicall_set(&self) -> bool {
        self.is_set(AppSettings::Multicall)
    }
}

// Internally used only
impl Command {
    pub(crate) fn get_override_usage(&self) -> Option<&StyledStr> {
        self.usage_str.as_ref()
    }

    pub(crate) fn get_override_help(&self) -> Option<&StyledStr> {
        self.help_str.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_help_template(&self) -> Option<&StyledStr> {
        self.template.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_term_width(&self) -> Option<usize> {
        self.term_w
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_max_term_width(&self) -> Option<usize> {
        self.max_w
    }

    pub(crate) fn get_replacement(&self, key: &str) -> Option<&[Str]> {
        self.replacers.get(key).map(|v| v.as_slice())
    }

    pub(crate) fn get_keymap(&self) -> &MKeyMap {
        &self.args
    }

    fn get_used_global_args(&self, matches: &ArgMatches, global_arg_vec: &mut Vec<Id>) {
        global_arg_vec.extend(
            self.args
                .args()
                .filter(|a| a.is_global_set())
                .map(|ga| ga.id.clone()),
        );
        if let Some((id, matches)) = matches.subcommand() {
            if let Some(used_sub) = self.find_subcommand(id) {
                used_sub.get_used_global_args(matches, global_arg_vec);
            }
        }
    }

    fn _do_parse(
        &mut self,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<ArgMatches> {
        debug!("Command::_do_parse");

        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing in case we run into a subcommand
        self._build_self(false);

        let mut matcher = ArgMatcher::new(self);

        // do the real parsing
        let mut parser = Parser::new(self);
        if let Err(error) = parser.get_matches_with(&mut matcher, raw_args, args_cursor) {
            if self.is_set(AppSettings::IgnoreErrors) {
                debug!("Command::_do_parse: ignoring error: {}", error);
            } else {
                return Err(error);
            }
        }

        let mut global_arg_vec = Default::default();
        self.get_used_global_args(&matcher, &mut global_arg_vec);

        matcher.propagate_globals(&global_arg_vec);

        Ok(matcher.into_inner())
    }

    /// Prepare for introspecting on all included [`Command`]s
    ///
    /// Call this on the top-level [`Command`] when done building and before reading state for
    /// cases like completions, custom help output, etc.
    pub fn build(&mut self) {
        self._build_recursive(true);
        self._build_bin_names_internal();
    }

    pub(crate) fn _build_recursive(&mut self, expand_help_tree: bool) {
        self._build_self(expand_help_tree);
        for subcmd in self.get_subcommands_mut() {
            subcmd._build_recursive(expand_help_tree);
        }
    }

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

    pub(crate) fn _build_subcommand(&mut self, name: &str) -> Option<&mut Self> {
        use std::fmt::Write;

        let mut mid_string = String::from(" ");
        #[cfg(feature = "usage")]
        if !self.is_subcommand_negates_reqs_set() && !self.is_args_conflicts_with_subcommands_set()
        {
            let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

            for s in &reqs {
                mid_string.push_str(&s.to_string());
                mid_string.push(' ');
            }
        }
        let is_multicall_set = self.is_multicall_set();

        let sc = some!(self.subcommands.iter_mut().find(|s| s.name == name));

        // Display subcommand name, short and long in usage
        let mut sc_names = String::new();
        sc_names.push_str(sc.name.as_str());
        let mut flag_subcmd = false;
        if let Some(l) = sc.get_long_flag() {
            write!(sc_names, "|--{}", l).unwrap();
            flag_subcmd = true;
        }
        if let Some(s) = sc.get_short_flag() {
            write!(sc_names, "|-{}", s).unwrap();
            flag_subcmd = true;
        }

        if flag_subcmd {
            sc_names = format!("{{{}}}", sc_names);
        }

        let usage_name = self
            .bin_name
            .as_ref()
            .map(|bin_name| format!("{}{}{}", bin_name, mid_string, sc_names))
            .unwrap_or(sc_names);
        sc.usage_name = Some(usage_name);

        // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
        // a space
        let bin_name = format!(
            "{}{}{}",
            self.bin_name.as_deref().unwrap_or_default(),
            if self.bin_name.is_some() { " " } else { "" },
            &*sc.name
        );
        debug!(
            "Command::_build_subcommand Setting bin_name of {} to {:?}",
            sc.name, bin_name
        );
        sc.bin_name = Some(bin_name);

        if sc.display_name.is_none() {
            let self_display_name = if is_multicall_set {
                self.display_name.as_deref().unwrap_or("")
            } else {
                self.display_name.as_deref().unwrap_or(&self.name)
            };
            let display_name = format!(
                "{}{}{}",
                self_display_name,
                if !self_display_name.is_empty() {
                    "-"
                } else {
                    ""
                },
                &*sc.name
            );
            debug!(
                "Command::_build_subcommand Setting display_name of {} to {:?}",
                sc.name, display_name
            );
            sc.display_name = Some(display_name);
        }

        // Ensure all args are built and ready to parse
        sc._build_self(false);

        Some(sc)
    }

    fn _build_bin_names_internal(&mut self) {
        debug!("Command::_build_bin_names");

        if !self.is_set(AppSettings::BinNameBuilt) {
            let mut mid_string = String::from(" ");
            #[cfg(feature = "usage")]
            if !self.is_subcommand_negates_reqs_set()
                && !self.is_args_conflicts_with_subcommands_set()
            {
                let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

                for s in &reqs {
                    mid_string.push_str(&s.to_string());
                    mid_string.push(' ');
                }
            }
            let is_multicall_set = self.is_multicall_set();

            let self_bin_name = if is_multicall_set {
                self.bin_name.as_deref().unwrap_or("")
            } else {
                self.bin_name.as_deref().unwrap_or(&self.name)
            }
            .to_owned();

            for mut sc in &mut self.subcommands {
                debug!("Command::_build_bin_names:iter: bin_name set...");

                if sc.usage_name.is_none() {
                    use std::fmt::Write;
                    // Display subcommand name, short and long in usage
                    let mut sc_names = String::new();
                    sc_names.push_str(sc.name.as_str());
                    let mut flag_subcmd = false;
                    if let Some(l) = sc.get_long_flag() {
                        write!(sc_names, "|--{}", l).unwrap();
                        flag_subcmd = true;
                    }
                    if let Some(s) = sc.get_short_flag() {
                        write!(sc_names, "|-{}", s).unwrap();
                        flag_subcmd = true;
                    }

                    if flag_subcmd {
                        sc_names = format!("{{{}}}", sc_names);
                    }

                    let usage_name = format!("{}{}{}", self_bin_name, mid_string, sc_names);
                    debug!(
                        "Command::_build_bin_names:iter: Setting usage_name of {} to {:?}",
                        sc.name, usage_name
                    );
                    sc.usage_name = Some(usage_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing usage_name of {} ({:?})",
                        sc.name, sc.usage_name
                    );
                }

                if sc.bin_name.is_none() {
                    let bin_name = format!(
                        "{}{}{}",
                        self_bin_name,
                        if !self_bin_name.is_empty() { " " } else { "" },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting bin_name of {} to {:?}",
                        sc.name, bin_name
                    );
                    sc.bin_name = Some(bin_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing bin_name of {} ({:?})",
                        sc.name, sc.bin_name
                    );
                }

                if sc.display_name.is_none() {
                    let self_display_name = if is_multicall_set {
                        self.display_name.as_deref().unwrap_or("")
                    } else {
                        self.display_name.as_deref().unwrap_or(&self.name)
                    };
                    let display_name = format!(
                        "{}{}{}",
                        self_display_name,
                        if !self_display_name.is_empty() {
                            "-"
                        } else {
                            ""
                        },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting display_name of {} to {:?}",
                        sc.name, display_name
                    );
                    sc.display_name = Some(display_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing display_name of {} ({:?})",
                        sc.name, sc.display_name
                    );
                }

                sc._build_bin_names_internal();
            }
            self.set(AppSettings::BinNameBuilt);
        } else {
            debug!("Command::_build_bin_names: already built");
        }
    }

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

    /// Propagate settings
    pub(crate) fn _propagate(&mut self) {
        debug!("Command::_propagate:{}", self.name);
        let mut subcommands = std::mem::take(&mut self.subcommands);
        for sc in &mut subcommands {
            self._propagate_subcommand(sc);
        }
        self.subcommands = subcommands;
    }

    fn _propagate_subcommand(&self, sc: &mut Self) {
        // We have to create a new scope in order to tell rustc the borrow of `sc` is
        // done and to recursively call this method
        {
            if self.settings.is_set(AppSettings::PropagateVersion) {
                if let Some(version) = self.version.as_ref() {
                    sc.version.get_or_insert_with(|| version.clone());
                }
                if let Some(long_version) = self.long_version.as_ref() {
                    sc.long_version.get_or_insert_with(|| long_version.clone());
                }
            }

            sc.settings = sc.settings | self.g_settings;
            sc.g_settings = sc.g_settings | self.g_settings;
            sc.term_w = self.term_w;
            sc.max_w = self.max_w;
        }
    }

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

Adds multiple arguments to the list of valid possibilities.

Examples
Command::new("myprog")
    .args([
        arg!("[debug] -d 'turns on debugging info'"),
        Arg::new("input").help("the input file to use")
    ])

Allows one to mutate an Arg after it’s been added to a Command.

This can be useful for modifying the auto-generated help or version arguments.

Panics

If the argument is undefined

Examples

let mut cmd = Command::new("foo")
    .arg(Arg::new("bar")
        .short('b')
        .action(ArgAction::SetTrue))
    .mut_arg("bar", |a| a.short('B'));

let res = cmd.try_get_matches_from_mut(vec!["foo", "-b"]);

// Since we changed `bar`'s short to "B" this should err as there
// is no `-b` anymore, only `-B`

assert!(res.is_err());

let res = cmd.try_get_matches_from_mut(vec!["foo", "-B"]);
assert!(res.is_ok());

Allows one to mutate a Command after it’s been added as a subcommand.

This can be useful for modifying auto-generated arguments of nested subcommands with Command::mut_arg.

Panics

If the subcommand is undefined

Examples

let mut cmd = Command::new("foo")
        .subcommand(Command::new("bar"))
        .mut_subcommand("bar", |subcmd| subcmd.disable_help_flag(true));

let res = cmd.try_get_matches_from_mut(vec!["foo", "bar", "--help"]);

// Since we disabled the help flag on the "bar" subcommand, this should err.

assert!(res.is_err());

let res = cmd.try_get_matches_from_mut(vec!["foo", "bar"]);
assert!(res.is_ok());

Adds an ArgGroup to the application.

ArgGroups are a family of related arguments. By placing them in a logical group, you can build easier requirement and exclusion rules.

Example use cases:

  • Make an entire ArgGroup required, meaning that one (and only one) argument from that group must be present at runtime.
  • Name an ArgGroup as a conflict to another argument. Meaning any of the arguments that belong to that group will cause a failure if present with the conflicting argument.
  • Ensure exclusion between arguments.
  • Extract a value from a group instead of determining exactly which argument was used.
Examples

The following example demonstrates using an ArgGroup to ensure that one, and only one, of the arguments from the specified group is present at runtime.

Command::new("cmd")
    .arg(arg!("--set-ver [ver] 'set the version manually'"))
    .arg(arg!("--major 'auto increase major'"))
    .arg(arg!("--minor 'auto increase minor'"))
    .arg(arg!("--patch 'auto increase patch'"))
    .group(ArgGroup::new("vers")
         .args(["set-ver", "major", "minor","patch"])
         .required(true))
Examples found in repository?
src/builder/command.rs (line 360)
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    pub fn groups(mut self, groups: impl IntoIterator<Item = impl Into<ArgGroup>>) -> Self {
        for g in groups.into_iter() {
            self = self.group(g.into());
        }
        self
    }

Adds multiple ArgGroups to the Command at once.

Examples
Command::new("cmd")
    .arg(arg!("--set-ver [ver] 'set the version manually'"))
    .arg(arg!("--major         'auto increase major'"))
    .arg(arg!("--minor         'auto increase minor'"))
    .arg(arg!("--patch         'auto increase patch'"))
    .arg(arg!("-c [FILE]       'a config file'"))
    .arg(arg!("-i [IFACE]      'an interface'"))
    .groups([
        ArgGroup::new("vers")
            .args(["set-ver", "major", "minor","patch"])
            .required(true),
        ArgGroup::new("input")
            .args(["c", "i"])
    ])

Adds a subcommand to the list of valid possibilities.

Subcommands are effectively sub-Commands, because they can contain their own arguments, subcommands, version, usage, etc. They also function just like Commands, in that they get their own auto generated help, version, and usage.

A subcommand’s Command::name will be used for:

  • The argument the user passes in
  • Programmatically looking up the subcommand
Examples
Command::new("myprog")
    .subcommand(Command::new("config")
        .about("Controls configuration features")
        .arg(arg!("<config> 'Required configuration file to use'")))
Examples found in repository?
src/builder/command.rs (line 419)
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    pub fn subcommands(mut self, subcmds: impl IntoIterator<Item = impl Into<Self>>) -> Self {
        for subcmd in subcmds {
            self = self.subcommand(subcmd);
        }
        self
    }

    /// Catch problems earlier in the development cycle.
    ///
    /// Most error states are handled as asserts under the assumption they are programming mistake
    /// and not something to handle at runtime.  Rather than relying on tests (manual or automated)
    /// that exhaustively test your CLI to ensure the asserts are evaluated, this will run those
    /// asserts in a way convenient for running as a test.
    ///
    /// **Note::** This will not help with asserts in [`ArgMatches`], those will need exhaustive
    /// testing of your CLI.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// fn cmd() -> Command {
    ///     Command::new("foo")
    ///         .arg(
    ///             Arg::new("bar").short('b').action(ArgAction::SetTrue)
    ///         )
    /// }
    ///
    /// #[test]
    /// fn verify_app() {
    ///     cmd().debug_assert();
    /// }
    ///
    /// fn main() {
    ///     let m = cmd().get_matches_from(vec!["foo", "-b"]);
    ///     println!("{}", *m.get_one::<bool>("bar").expect("defaulted by clap"));
    /// }
    /// ```
    pub fn debug_assert(mut self) {
        self.build();
    }

    /// Custom error message for post-parsing validation
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("myprog");
    /// let err = cmd.error(ErrorKind::InvalidValue, "Some failure case");
    /// ```
    pub fn error(&mut self, kind: ErrorKind, message: impl std::fmt::Display) -> Error {
        Error::raw(kind, message).format(self)
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::try_get_matches_from_mut`]: Command::try_get_matches_from_mut()
    #[inline]
    pub fn get_matches(self) -> ArgMatches {
        self.get_matches_from(&mut env::args_os())
    }

    /// Parse [`env::args_os`], exiting on failure.
    ///
    /// Like [`Command::get_matches`] but doesn't consume the `Command`.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let mut cmd = Command::new("myprog")
    ///     // Args and options go here...
    ///     ;
    /// let matches = cmd.get_matches_mut();
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Command::get_matches`]: Command::get_matches()
    pub fn get_matches_mut(&mut self) -> ArgMatches {
        self.try_get_matches_from_mut(&mut env::args_os())
            .unwrap_or_else(|e| e.exit())
    }

    /// Parse [`env::args_os`], returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a
    /// [`ErrorKind::DisplayHelp`] or [`ErrorKind::DisplayVersion`] respectively. You must call
    /// [`Error::exit`] or perform a [`std::process::exit`].
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches()
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    #[inline]
    pub fn try_get_matches(self) -> ClapResult<ArgMatches> {
        // Start the parsing
        self.try_get_matches_from(&mut env::args_os())
    }

    /// Parse the specified arguments, exiting on failure.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches_from(arg_vec);
    /// ```
    /// [`Command::get_matches`]: Command::get_matches()
    /// [`clap::Result`]: Result
    /// [`Vec`]: std::vec::Vec
    pub fn get_matches_from<I, T>(mut self, itr: I) -> ArgMatches
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr).unwrap_or_else(|e| {
            drop(self);
            e.exit()
        })
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches_from(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::get_matches_from`]: Command::get_matches_from()
    /// [`Command::try_get_matches`]: Command::try_get_matches()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Error`]: crate::Error
    /// [`Error::exit`]: crate::Error::exit()
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    /// [`clap::Result`]: Result
    pub fn try_get_matches_from<I, T>(mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr)
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// Like [`Command::try_get_matches_from`] but doesn't consume the `Command`.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let mut cmd = Command::new("myprog");
    ///     // Args and options go here...
    /// let matches = cmd.try_get_matches_from_mut(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::try_get_matches_from`]: Command::try_get_matches_from()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    pub fn try_get_matches_from_mut<I, T>(&mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut raw_args = clap_lex::RawArgs::new(itr.into_iter());
        let mut cursor = raw_args.cursor();

        if self.settings.is_set(AppSettings::Multicall) {
            if let Some(argv0) = raw_args.next_os(&mut cursor) {
                let argv0 = Path::new(&argv0);
                if let Some(command) = argv0.file_stem().and_then(|f| f.to_str()) {
                    // Stop borrowing command so we can get another mut ref to it.
                    let command = command.to_owned();
                    debug!(
                        "Command::try_get_matches_from_mut: Parsed command {} from argv",
                        command
                    );

                    debug!("Command::try_get_matches_from_mut: Reinserting command into arguments so subcommand parser matches it");
                    raw_args.insert(&cursor, [&command]);
                    debug!("Command::try_get_matches_from_mut: Clearing name and bin_name so that displayed command name starts with applet name");
                    self.name = "".into();
                    self.bin_name = None;
                    return self._do_parse(&mut raw_args, cursor);
                }
            }
        };

        // Get the name of the program (argument 1 of env::args()) and determine the
        // actual file
        // that was used to execute the program. This is because a program called
        // ./target/release/my_prog -a
        // will have two arguments, './target/release/my_prog', '-a' but we don't want
        // to display
        // the full path when displaying help messages and such
        if !self.settings.is_set(AppSettings::NoBinaryName) {
            if let Some(name) = raw_args.next_os(&mut cursor) {
                let p = Path::new(name);

                if let Some(f) = p.file_name() {
                    if let Some(s) = f.to_str() {
                        if self.bin_name.is_none() {
                            self.bin_name = Some(s.to_owned());
                        }
                    }
                }
            }
        }

        self._do_parse(&mut raw_args, cursor)
    }

    /// Prints the short help message (`-h`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    pub fn print_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Prints the long help message (`--help`) to [`io::stdout()`].
    ///
    /// See also [`Command::print_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// let mut cmd = Command::new("myprog");
    /// cmd.print_long_help();
    /// ```
    /// [`io::stdout()`]: std::io::stdout()
    /// [`BufWriter`]: std::io::BufWriter
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn print_long_help(&mut self) -> io::Result<()> {
        self._build_self(false);
        let color = self.color_help();

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);

        let c = Colorizer::new(Stream::Stdout, color).with_content(styled);
        c.print()
    }

    /// Render the short help message (`-h`) to a [`StyledStr`]
    ///
    /// See also [`Command::render_long_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        styled
    }

    /// Render the long help message (`--help`) to a [`StyledStr`].
    ///
    /// See also [`Command::render_help`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// let mut out = io::stdout();
    /// let help = cmd.render_long_help();
    /// println!("{}", help);
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-h` (short)]: Arg::help()
    /// [`--help` (long)]: Arg::long_help()
    pub fn render_long_help(&mut self) -> StyledStr {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        styled
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_help`")
    )]
    pub fn write_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, false);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Command::render_long_help`")
    )]
    pub fn write_long_help<W: io::Write>(&mut self, w: &mut W) -> io::Result<()> {
        self._build_self(false);

        let mut styled = StyledStr::new();
        let usage = Usage::new(self);
        write_help(&mut styled, self, &usage, true);
        ok!(write!(w, "{}", styled));
        w.flush()
    }

    /// Version message rendered as if the user ran `-V`.
    ///
    /// See also [`Command::render_long_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_version(&self) -> String {
        self._render_version(false)
    }

    /// Version message rendered as if the user ran `--version`.
    ///
    /// See also [`Command::render_version`].
    ///
    /// ### Coloring
    ///
    /// This function does not try to color the message nor it inserts any [ANSI escape codes].
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let cmd = Command::new("myprog");
    /// println!("{}", cmd.render_long_version());
    /// ```
    /// [`io::Write`]: std::io::Write
    /// [`-V` (short)]: Command::version()
    /// [`--version` (long)]: Command::long_version()
    /// [ANSI escape codes]: https://en.wikipedia.org/wiki/ANSI_escape_code
    pub fn render_long_version(&self) -> String {
        self._render_version(true)
    }

    /// Usage statement
    ///
    /// ### Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// use std::io;
    /// let mut cmd = Command::new("myprog");
    /// println!("{}", cmd.render_usage());
    /// ```
    pub fn render_usage(&mut self) -> StyledStr {
        self.render_usage_().unwrap_or_default()
    }

    pub(crate) fn render_usage_(&mut self) -> Option<StyledStr> {
        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing incase we run into a subcommand
        self._build_self(false);

        Usage::new(self).create_usage_with_title(&[])
    }
}

/// # Application-wide Settings
///
/// These settings will apply to the top-level command and all subcommands, by default.  Some
/// settings can be overridden in subcommands.
impl Command {
    /// Specifies that the parser should not assume the first argument passed is the binary name.
    ///
    /// This is normally the case when using a "daemon" style mode.  For shells / REPLs, see
    /// [`Command::multicall`][Command::multicall].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let m = Command::new("myprog")
    ///     .no_binary_name(true)
    ///     .arg(arg!(<cmd> ... "commands to run"))
    ///     .get_matches_from(vec!["command", "set"]);
    ///
    /// let cmds: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
    /// assert_eq!(cmds, ["command", "set"]);
    /// ```
    /// [`try_get_matches_from_mut`]: crate::Command::try_get_matches_from_mut()
    #[inline]
    pub fn no_binary_name(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NoBinaryName)
        } else {
            self.unset_global_setting(AppSettings::NoBinaryName)
        }
    }

    /// Try not to fail on parse errors, like missing option values.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, arg};
    /// let cmd = Command::new("cmd")
    ///   .ignore_errors(true)
    ///   .arg(arg!(-c --config <FILE> "Sets a custom config file"))
    ///   .arg(arg!(-x --stuff <FILE> "Sets a custom stuff file"))
    ///   .arg(arg!(f: -f "Flag"));
    ///
    /// let r = cmd.try_get_matches_from(vec!["cmd", "-c", "file", "-f", "-x"]);
    ///
    /// assert!(r.is_ok(), "unexpected error: {:?}", r);
    /// let m = r.unwrap();
    /// assert_eq!(m.get_one::<String>("config").unwrap(), "file");
    /// assert!(*m.get_one::<bool>("f").expect("defaulted"));
    /// assert_eq!(m.get_one::<String>("stuff"), None);
    /// ```
    #[inline]
    pub fn ignore_errors(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::IgnoreErrors)
        } else {
            self.unset_global_setting(AppSettings::IgnoreErrors)
        }
    }

    /// Replace prior occurrences of arguments rather than error
    ///
    /// For any argument that would conflict with itself by default (e.g.
    /// [`ArgAction::Set`][ArgAction::Set], it will now override itself.
    ///
    /// This is the equivalent to saying the `foo` arg using [`Arg::overrides_with("foo")`] for all
    /// defined arguments.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [`Arg::overrides_with("foo")`]: crate::Arg::overrides_with()
    #[inline]
    pub fn args_override_self(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::AllArgsOverrideSelf)
        } else {
            self.unset_global_setting(AppSettings::AllArgsOverrideSelf)
        }
    }

    /// Disables the automatic delimiting of values after `--` or when [`Command::trailing_var_arg`]
    /// was used.
    ///
    /// **NOTE:** The same thing can be done manually by setting the final positional argument to
    /// [`Arg::value_delimiter(None)`]. Using this setting is safer, because it's easier to locate
    /// when making changes.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .dont_delimit_trailing_values(true)
    ///     .get_matches();
    /// ```
    ///
    /// [`Arg::value_delimiter(None)`]: crate::Arg::value_delimiter()
    #[inline]
    pub fn dont_delimit_trailing_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DontDelimitTrailingValues)
        } else {
            self.unset_global_setting(AppSettings::DontDelimitTrailingValues)
        }
    }

    /// Sets when to color output.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// **NOTE:** Default behaviour is [`ColorChoice::Auto`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, ColorChoice};
    /// Command::new("myprog")
    ///     .color(ColorChoice::Never)
    ///     .get_matches();
    /// ```
    /// [`ColorChoice::Auto`]: crate::ColorChoice::Auto
    #[cfg(feature = "color")]
    #[inline]
    #[must_use]
    pub fn color(self, color: ColorChoice) -> Self {
        let cmd = self
            .unset_global_setting(AppSettings::ColorAuto)
            .unset_global_setting(AppSettings::ColorAlways)
            .unset_global_setting(AppSettings::ColorNever);
        match color {
            ColorChoice::Auto => cmd.global_setting(AppSettings::ColorAuto),
            ColorChoice::Always => cmd.global_setting(AppSettings::ColorAlways),
            ColorChoice::Never => cmd.global_setting(AppSettings::ColorNever),
        }
    }

    /// Sets the terminal width at which to wrap help messages.
    ///
    /// Using `0` will ignore terminal widths and use source formatting.
    ///
    /// Defaults to current terminal width when `wrap_help` feature flag is enabled.  If the flag
    /// is disabled or it cannot be determined, the default is 100.
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .term_width(80)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn term_width(mut self, width: usize) -> Self {
        self.term_w = Some(width);
        self
    }

    /// Limit the line length for wrapping help when using the current terminal's width.
    ///
    /// This only applies when [`term_width`][Command::term_width] is unset so that the current
    /// terminal's width will be used.  See [`Command::term_width`] for more details.
    ///
    /// Using `0` will ignore terminal widths and use source formatting (default).
    ///
    /// **NOTE:** This setting applies globally and *not* on a per-command basis.
    ///
    /// **NOTE:** This requires the [`wrap_help` feature][crate::_features]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .max_term_width(100)
    /// # ;
    /// ```
    #[inline]
    #[must_use]
    #[cfg(any(not(feature = "unstable-v5"), feature = "wrap_help"))]
    pub fn max_term_width(mut self, w: usize) -> Self {
        self.max_w = Some(w);
        self
    }

    /// Disables `-V` and `--version` flag.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_version_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-V"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_version_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableVersionFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableVersionFlag)
        }
    }

    /// Specifies to use the version of the current command for all [`subcommands`].
    ///
    /// Defaults to `false`; subcommands have independent version strings from their parents.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .version("v1.1")
    ///     .propagate_version(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches();
    /// // running `$ myprog test --version` will display
    /// // "myprog-test v1.1"
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    #[inline]
    pub fn propagate_version(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::PropagateVersion)
        } else {
            self.unset_global_setting(AppSettings::PropagateVersion)
        }
    }

    /// Places the help string for all arguments and subcommands on the line after them.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .next_line_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn next_line_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::NextLineHelp)
        } else {
            self.unset_global_setting(AppSettings::NextLineHelp)
        }
    }

    /// Disables `-h` and `--help` flag.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_flag(true)
    ///     .try_get_matches_from(vec![
    ///         "myprog", "-h"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// ```
    #[inline]
    pub fn disable_help_flag(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpFlag)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpFlag)
        }
    }

    /// Disables the `help` [`subcommand`].
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let res = Command::new("myprog")
    ///     .disable_help_subcommand(true)
    ///     // Normally, creating a subcommand causes a `help` subcommand to automatically
    ///     // be generated as well
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "help"
    ///     ]);
    /// assert!(res.is_err());
    /// assert_eq!(res.unwrap_err().kind(), ErrorKind::InvalidSubcommand);
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn disable_help_subcommand(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableHelpSubcommand)
        } else {
            self.unset_global_setting(AppSettings::DisableHelpSubcommand)
        }
    }

    /// Disables colorized help messages.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .disable_colored_help(true)
    ///     .get_matches();
    /// ```
    #[inline]
    pub fn disable_colored_help(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::DisableColoredHelp)
        } else {
            self.unset_global_setting(AppSettings::DisableColoredHelp)
        }
    }

    /// Panic if help descriptions are omitted.
    ///
    /// **NOTE:** When deriving [`Parser`][crate::Parser], you could instead check this at
    /// compile-time with `#![deny(missing_docs)]`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo").help("It does foo stuff")
    ///         // As required via `help_expected`, a help message was supplied
    ///      )
    /// #    .get_matches();
    /// ```
    ///
    /// # Panics
    ///
    /// ```rust,no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .help_expected(true)
    ///     .arg(
    ///         Arg::new("foo")
    ///         // Someone forgot to put .about("...") here
    ///         // Since the setting `help_expected` is activated, this will lead to
    ///         // a panic (if you are in debug mode)
    ///     )
    /// #   .get_matches();
    ///```
    #[inline]
    pub fn help_expected(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HelpExpected)
        } else {
            self.unset_global_setting(AppSettings::HelpExpected)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn dont_collapse_args_in_usage(self, _yes: bool) -> Self {
        self
    }

    /// Tells `clap` *not* to print possible values when displaying help information.
    ///
    /// This can be useful if there are many values, or they are explained elsewhere.
    ///
    /// To set this per argument, see
    /// [`Arg::hide_possible_values`][crate::Arg::hide_possible_values].
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    #[inline]
    pub fn hide_possible_values(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::HidePossibleValues)
        } else {
            self.unset_global_setting(AppSettings::HidePossibleValues)
        }
    }

    /// Allow partial matches of long arguments or their [aliases].
    ///
    /// For example, to match an argument named `--test`, one could use `--t`, `--te`, `--tes`, and
    /// `--test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match
    /// `--te` to `--test` there could not also be another argument or alias `--temp` because both
    /// start with `--te`
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_long_args(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferLongArgs)
        } else {
            self.unset_global_setting(AppSettings::InferLongArgs)
        }
    }

    /// Allow partial matches of [subcommand] names and their [aliases].
    ///
    /// For example, to match a subcommand named `test`, one could use `t`, `te`, `tes`, and
    /// `test`.
    ///
    /// **NOTE:** The match *must not* be ambiguous at all in order to succeed. i.e. to match `te`
    /// to `test` there could not also be a subcommand or alias `temp` because both start with `te`
    ///
    /// **CAUTION:** This setting can interfere with [positional/free arguments], take care when
    /// designing CLIs which allow inferred subcommands and have potential positional/free
    /// arguments whose values could start with the same characters as subcommands. If this is the
    /// case, it's recommended to use settings such as [`Command::args_conflicts_with_subcommands`] in
    /// conjunction with this setting.
    ///
    /// **NOTE:** This choice is propagated to all child subcommands.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("prog")
    ///     .infer_subcommands(true)
    ///     .subcommand(Command::new("test"))
    ///     .get_matches_from(vec![
    ///         "prog", "te"
    ///     ]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    ///
    /// [subcommand]: crate::Command::subcommand()
    /// [positional/free arguments]: crate::Arg::index()
    /// [aliases]: crate::Command::aliases()
    #[inline]
    pub fn infer_subcommands(self, yes: bool) -> Self {
        if yes {
            self.global_setting(AppSettings::InferSubcommands)
        } else {
            self.unset_global_setting(AppSettings::InferSubcommands)
        }
    }
}

/// # Command-specific Settings
///
/// These apply only to the current command and are not inherited by subcommands.
impl Command {
    /// (Re)Sets the program's name.
    ///
    /// See [`Command::new`] for more details.
    ///
    /// # Examples
    ///
    /// ```ignore
    /// let cmd = clap::command!()
    ///     .name("foo");
    ///
    /// // continued logic goes here, such as `cmd.get_matches()` etc.
    /// ```
    #[must_use]
    pub fn name(mut self, name: impl Into<Str>) -> Self {
        self.name = name.into();
        self
    }

    /// Overrides the runtime-determined name of the binary for help and error messages.
    ///
    /// This should only be used when absolutely necessary, such as when the binary name for your
    /// application is misleading, or perhaps *not* how the user should invoke your program.
    ///
    /// **Pro-tip:** When building things such as third party `cargo`
    /// subcommands, this setting **should** be used!
    ///
    /// **NOTE:** This *does not* change or set the name of the binary file on
    /// disk. It only changes what clap thinks the name is for the purposes of
    /// error or help messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .bin_name("my_binary")
    /// # ;
    /// ```
    #[must_use]
    pub fn bin_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.bin_name = name.into_resettable().into_option();
        self
    }

    /// Overrides the runtime-determined display name of the program for help and error messages.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("My Program")
    ///      .display_name("my_program")
    /// # ;
    /// ```
    #[must_use]
    pub fn display_name(mut self, name: impl IntoResettable<String>) -> Self {
        self.display_name = name.into_resettable().into_option();
        self
    }

    /// Sets the author(s) for the help message.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_authors!`] to
    /// automatically set your application's author(s) to the same thing as your
    /// crate at compile time.
    ///
    /// **NOTE:** A custom [`help_template`][Command::help_template] is needed for author to show
    /// up.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///      .author("Me, me@mymain.com")
    /// # ;
    /// ```
    #[must_use]
    pub fn author(mut self, author: impl IntoResettable<Str>) -> Self {
        self.author = author.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the short help (`-h`).
    ///
    /// If [`Command::long_about`] is not specified, this message will be displayed for `--help`.
    ///
    /// **NOTE:** Only `Command::about` (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// See also [`crate_description!`](crate::crate_description!).
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .about("Does really amazing things for great people")
    /// # ;
    /// ```
    #[must_use]
    pub fn about(mut self, about: impl IntoResettable<StyledStr>) -> Self {
        self.about = about.into_resettable().into_option();
        self
    }

    /// Sets the program's description for the long help (`--help`).
    ///
    /// If [`Command::about`] is not specified, this message will be displayed for `-h`.
    ///
    /// **NOTE:** Only [`Command::about`] (short format) is used in completion
    /// script generation in order to be concise.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_about(
    /// "Does really amazing things to great people. Now let's talk a little
    ///  more in depth about how this subcommand really works. It may take about
    ///  a few lines of text, but that's ok!")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    #[must_use]
    pub fn long_about(mut self, long_about: impl IntoResettable<StyledStr>) -> Self {
        self.long_about = long_about.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated short help (`-h`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_help("Does really amazing things for great people... but be careful with -R!")
    /// # ;
    /// ```
    ///
    #[must_use]
    pub fn after_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for after auto-generated long help (`--help`).
    ///
    /// This is often used to describe how to use the arguments, caveats to be noted, or license
    /// and contact information.
    ///
    /// If [`Command::after_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .after_long_help("Does really amazing things to great people... but be careful with -R, \
    ///                      like, for real, be careful with this!")
    /// # ;
    /// ```
    #[must_use]
    pub fn after_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.after_long_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated short help (`-h`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_long_help`] is not specified, this message will be displayed for `--help`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_help("Some info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_help = help.into_resettable().into_option();
        self
    }

    /// Free-form help text for before auto-generated long help (`--help`).
    ///
    /// This is often used for header, copyright, or license information.
    ///
    /// If [`Command::before_help`] is not specified, this message will be displayed for `-h`.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .before_long_help("Some verbose and long info I'd like to appear before the help info")
    /// # ;
    /// ```
    #[must_use]
    pub fn before_long_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.before_long_help = help.into_resettable().into_option();
        self
    }

    /// Sets the version for the short version (`-V`) and help messages.
    ///
    /// If [`Command::long_version`] is not specified, this message will be displayed for `--version`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("v0.1.24")
    /// # ;
    /// ```
    #[must_use]
    pub fn version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.version = ver.into_resettable().into_option();
        self
    }

    /// Sets the version for the long version (`--version`) and help messages.
    ///
    /// If [`Command::version`] is not specified, this message will be displayed for `-V`.
    ///
    /// **Pro-tip:** Use `clap`s convenience macro [`crate_version!`] to
    /// automatically set your application's version to the same thing as your
    /// crate at compile time.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .long_version(
    /// "v0.1.24
    ///  commit: abcdef89726d
    ///  revision: 123
    ///  release: 2
    ///  binary: myprog")
    /// # ;
    /// ```
    #[must_use]
    pub fn long_version(mut self, ver: impl IntoResettable<Str>) -> Self {
        self.long_version = ver.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated usage string for help and error messages.
    ///
    /// **NOTE:** Using this setting disables `clap`s "context-aware" usage
    /// strings. After this setting is set, this will be *the only* usage string
    /// displayed to the user!
    ///
    /// **NOTE:** Multiple usage lines may be present in the usage argument, but
    /// some rules need to be followed to ensure the usage lines are formatted
    /// correctly by the default help formatter:
    ///
    /// - Do not indent the first usage line.
    /// - Indent all subsequent usage lines with seven spaces.
    /// - The last line must not end with a newline.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage("myapp [-clDas] <some_file>")
    /// # ;
    /// ```
    ///
    /// Or for multiple usage lines:
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .override_usage(
    ///         "myapp -X [-a] [-b] <file>\n       \
    ///          myapp -Y [-c] <file1> <file2>\n       \
    ///          myapp -Z [-d|-e]"
    ///     )
    /// # ;
    /// ```
    ///
    /// [`ArgMatches::usage`]: ArgMatches::usage()
    #[must_use]
    pub fn override_usage(mut self, usage: impl IntoResettable<StyledStr>) -> Self {
        self.usage_str = usage.into_resettable().into_option();
        self
    }

    /// Overrides the `clap` generated help message (both `-h` and `--help`).
    ///
    /// This should only be used when the auto-generated message does not suffice.
    ///
    /// **NOTE:** This **only** replaces the help message for the current
    /// command, meaning if you are using subcommands, those help messages will
    /// still be auto-generated unless you specify a [`Command::override_help`] for
    /// them as well.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myapp")
    ///     .override_help("myapp v1.0\n\
    ///            Does awesome things\n\
    ///            (C) me@mail.com\n\n\
    ///
    ///            Usage: myapp <opts> <command>\n\n\
    ///
    ///            Options:\n\
    ///            -h, --help       Display this message\n\
    ///            -V, --version    Display version info\n\
    ///            -s <stuff>       Do something with stuff\n\
    ///            -v               Be verbose\n\n\
    ///
    ///            Commands:\n\
    ///            help             Print this message\n\
    ///            work             Do some work")
    /// # ;
    /// ```
    #[must_use]
    pub fn override_help(mut self, help: impl IntoResettable<StyledStr>) -> Self {
        self.help_str = help.into_resettable().into_option();
        self
    }

    /// Sets the help template to be used, overriding the default format.
    ///
    /// **NOTE:** The template system is by design very simple. Therefore, the
    /// tags have to be written in the lowercase and without spacing.
    ///
    /// Tags are given inside curly brackets.
    ///
    /// Valid tags are:
    ///
    ///   * `{name}`                - Display name for the (sub-)command.
    ///   * `{bin}`                 - Binary name.
    ///   * `{version}`             - Version number.
    ///   * `{author}`              - Author information.
    ///   * `{author-with-newline}` - Author followed by `\n`.
    ///   * `{author-section}`      - Author preceded and followed by `\n`.
    ///   * `{about}`               - General description (from [`Command::about`] or
    ///                               [`Command::long_about`]).
    ///   * `{about-with-newline}`  - About followed by `\n`.
    ///   * `{about-section}`       - About preceded and followed by '\n'.
    ///   * `{usage-heading}`       - Automatically generated usage heading.
    ///   * `{usage}`               - Automatically generated or given usage string.
    ///   * `{all-args}`            - Help for all arguments (options, flags, positional
    ///                               arguments, and subcommands) including titles.
    ///   * `{options}`             - Help for options.
    ///   * `{positionals}`         - Help for positional arguments.
    ///   * `{subcommands}`         - Help for subcommands.
    ///   * `{tag}`                 - Standard tab sized used within clap
    ///   * `{after-help}`          - Help from [`Command::after_help`] or [`Command::after_long_help`].
    ///   * `{before-help}`         - Help from [`Command::before_help`] or [`Command::before_long_help`].
    ///
    /// # Examples
    ///
    /// For a very brief help:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("{bin} ({version}) - {usage}")
    /// # ;
    /// ```
    ///
    /// For showing more application context:
    ///
    /// ```no_run
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .version("1.0")
    ///     .help_template("\
    /// {before-help}{name} {version}
    /// {author-with-newline}{about-with-newline}
    /// {usage-heading} {usage}
    ///
    /// {all-args}{after-help}
    /// ")
    /// # ;
    /// ```
    /// [`Command::about`]: Command::about()
    /// [`Command::long_about`]: Command::long_about()
    /// [`Command::after_help`]: Command::after_help()
    /// [`Command::after_long_help`]: Command::after_long_help()
    /// [`Command::before_help`]: Command::before_help()
    /// [`Command::before_long_help`]: Command::before_long_help()
    #[must_use]
    #[cfg(feature = "help")]
    pub fn help_template(mut self, s: impl IntoResettable<StyledStr>) -> Self {
        self.template = s.into_resettable().into_option();
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.insert(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_setting<F>(mut self, setting: F) -> Self
    where
        F: Into<AppFlags>,
    {
        self.settings.remove(setting.into());
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.set(setting);
        self.g_settings.set(setting);
        self
    }

    #[inline]
    #[must_use]
    pub(crate) fn unset_global_setting(mut self, setting: AppSettings) -> Self {
        self.settings.unset(setting);
        self.g_settings.unset(setting);
        self
    }

    /// Set the default section heading for future args.
    ///
    /// This will be used for any arg that hasn't had [`Arg::help_heading`] called.
    ///
    /// This is useful if the default `Options` or `Arguments` headings are
    /// not specific enough for one's use case.
    ///
    /// For subcommands, see [`Command::subcommand_help_heading`]
    ///
    /// [`Command::arg`]: Command::arg()
    /// [`Arg::help_heading`]: crate::Arg::help_heading()
    #[inline]
    #[must_use]
    pub fn next_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.current_help_heading = heading.into_resettable().into_option();
        self
    }

    /// Change the starting value for assigning future display orders for ags.
    ///
    /// This will be used for any arg that hasn't had [`Arg::display_order`] called.
    #[inline]
    #[must_use]
    pub fn next_display_order(mut self, disp_ord: impl IntoResettable<usize>) -> Self {
        self.current_disp_ord = disp_ord.into_resettable().into_option();
        self
    }

    /// Replaces an argument or subcommand used on the CLI at runtime with other arguments or subcommands.
    ///
    /// **Note:** This is gated behind [`unstable-replace`](https://github.com/clap-rs/clap/issues/2836)
    ///
    /// When this method is used, `name` is removed from the CLI, and `target`
    /// is inserted in its place. Parsing continues as if the user typed
    /// `target` instead of `name`.
    ///
    /// This can be used to create "shortcuts" for subcommands, or if a
    /// particular argument has the semantic meaning of several other specific
    /// arguments and values.
    ///
    /// # Examples
    ///
    /// We'll start with the "subcommand short" example. In this example, let's
    /// assume we have a program with a subcommand `module` which can be invoked
    /// via `cmd module`. Now let's also assume `module` also has a subcommand
    /// called `install` which can be invoked `cmd module install`. If for some
    /// reason users needed to be able to reach `cmd module install` via the
    /// short-hand `cmd install`, we'd have several options.
    ///
    /// We *could* create another sibling subcommand to `module` called
    /// `install`, but then we would need to manage another subcommand and manually
    /// dispatch to `cmd module install` handling code. This is error prone and
    /// tedious.
    ///
    /// We could instead use [`Command::replace`] so that, when the user types `cmd
    /// install`, `clap` will replace `install` with `module install` which will
    /// end up getting parsed as if the user typed the entire incantation.
    ///
    /// ```rust
    /// # use clap::Command;
    /// let m = Command::new("cmd")
    ///     .subcommand(Command::new("module")
    ///         .subcommand(Command::new("install")))
    ///     .replace("install", &["module", "install"])
    ///     .get_matches_from(vec!["cmd", "install"]);
    ///
    /// assert!(m.subcommand_matches("module").is_some());
    /// assert!(m.subcommand_matches("module").unwrap().subcommand_matches("install").is_some());
    /// ```
    ///
    /// Now let's show an argument example!
    ///
    /// Let's assume we have an application with two flags `--save-context` and
    /// `--save-runtime`. But often users end up needing to do *both* at the
    /// same time. We can add a third flag `--save-all` which semantically means
    /// the same thing as `cmd --save-context --save-runtime`. To implement that,
    /// we have several options.
    ///
    /// We could create this third argument and manually check if that argument
    /// and in our own consumer code handle the fact that both `--save-context`
    /// and `--save-runtime` *should* have been used. But again this is error
    /// prone and tedious. If we had code relying on checking `--save-context`
    /// and we forgot to update that code to *also* check `--save-all` it'd mean
    /// an error!
    ///
    /// Luckily we can use [`Command::replace`] so that when the user types
    /// `--save-all`, `clap` will replace that argument with `--save-context
    /// --save-runtime`, and parsing will continue like normal. Now all our code
    /// that was originally checking for things like `--save-context` doesn't
    /// need to change!
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .replace("--save-all", &["--save-context", "--save-runtime"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// ```
    ///
    /// This can also be used with options, for example if our application with
    /// `--save-*` above also had a `--format=TYPE` option. Let's say it
    /// accepted `txt` or `json` values. However, when `--save-all` is used,
    /// only `--format=json` is allowed, or valid. We could change the example
    /// above to enforce this:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let m = Command::new("cmd")
    ///     .arg(Arg::new("save-context")
    ///         .long("save-context")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("save-runtime")
    ///         .long("save-runtime")
    ///         .action(ArgAction::SetTrue))
    ///     .arg(Arg::new("format")
    ///         .long("format")
    ///         .action(ArgAction::Set)
    ///         .value_parser(["txt", "json"]))
    ///     .replace("--save-all", &["--save-context", "--save-runtime", "--format=json"])
    ///     .get_matches_from(vec!["cmd", "--save-all"]);
    ///
    /// assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
    /// assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
    /// assert_eq!(m.get_one::<String>("format").unwrap(), "json");
    /// ```
    ///
    /// [`Command::replace`]: Command::replace()
    #[inline]
    #[cfg(feature = "unstable-replace")]
    #[must_use]
    pub fn replace(
        mut self,
        name: impl Into<Str>,
        target: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        self.replacers
            .insert(name.into(), target.into_iter().map(Into::into).collect());
        self
    }

    /// Exit gracefully if no arguments are present (e.g. `$ myprog`).
    ///
    /// **NOTE:** [`subcommands`] count as arguments
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command};
    /// Command::new("myprog")
    ///     .arg_required_else_help(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    /// [`Arg::default_value`]: crate::Arg::default_value()
    #[inline]
    pub fn arg_required_else_help(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgRequiredElseHelp)
        } else {
            self.unset_setting(AppSettings::ArgRequiredElseHelp)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_hyphen_values`")
    )]
    pub fn allow_hyphen_values(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowHyphenValues)
        } else {
            self.unset_setting(AppSettings::AllowHyphenValues)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::allow_negative_numbers`")
    )]
    pub fn allow_negative_numbers(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowNegativeNumbers)
        } else {
            self.unset_setting(AppSettings::AllowNegativeNumbers)
        }
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::trailing_var_arg`")
    )]
    pub fn trailing_var_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::TrailingVarArg)
        } else {
            self.unset_setting(AppSettings::TrailingVarArg)
        }
    }

    /// Allows one to implement two styles of CLIs where positionals can be used out of order.
    ///
    /// The first example is a CLI where the second to last positional argument is optional, but
    /// the final positional argument is required. Such as `$ prog [optional] <required>` where one
    /// of the two following usages is allowed:
    ///
    /// * `$ prog [optional] <required>`
    /// * `$ prog <required>`
    ///
    /// This would otherwise not be allowed. This is useful when `[optional]` has a default value.
    ///
    /// **Note:** when using this style of "missing positionals" the final positional *must* be
    /// [required] if `--` will not be used to skip to the final positional argument.
    ///
    /// **Note:** This style also only allows a single positional argument to be "skipped" without
    /// the use of `--`. To skip more than one, see the second example.
    ///
    /// The second example is when one wants to skip multiple optional positional arguments, and use
    /// of the `--` operator is OK (but not required if all arguments will be specified anyways).
    ///
    /// For example, imagine a CLI which has three positional arguments `[foo] [bar] [baz]...` where
    /// `baz` accepts multiple values (similar to man `ARGS...` style training arguments).
    ///
    /// With this setting the following invocations are posisble:
    ///
    /// * `$ prog foo bar baz1 baz2 baz3`
    /// * `$ prog foo -- baz1 baz2 baz3`
    /// * `$ prog -- baz1 baz2 baz3`
    ///
    /// # Examples
    ///
    /// Style number one from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1"), None);
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Now the same example, but using a default value for the first optional positional argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("arg1")
    ///         .default_value("something"))
    ///     .arg(Arg::new("arg2")
    ///         .required(true))
    ///     .get_matches_from(vec![
    ///         "prog", "other"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("arg1").unwrap(), "something");
    /// assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");
    /// ```
    ///
    /// Style number two from above:
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "foo", "bar", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo").unwrap(), "foo");
    /// assert_eq!(m.get_one::<String>("bar").unwrap(), "bar");
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// Now nofice if we don't specify `foo` or `baz` but use the `--` operator.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_missing_positional(true)
    ///     .arg(Arg::new("foo"))
    ///     .arg(Arg::new("bar"))
    ///     .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    ///     .get_matches_from(vec![
    ///         "prog", "--", "baz1", "baz2", "baz3"
    ///     ]);
    ///
    /// assert_eq!(m.get_one::<String>("foo"), None);
    /// assert_eq!(m.get_one::<String>("bar"), None);
    /// assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);
    /// ```
    ///
    /// [required]: crate::Arg::required()
    #[inline]
    pub fn allow_missing_positional(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowMissingPositional)
        } else {
            self.unset_setting(AppSettings::AllowMissingPositional)
        }
    }
}

/// # Subcommand-specific Settings
impl Command {
    /// Sets the short version of the subcommand flag without the preceding `-`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::short`].
    ///
    /// # Examples
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").short_flag('S').arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "-Ss"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    /// [`Arg::short`]: Arg::short()
    #[must_use]
    pub fn short_flag(mut self, short: impl IntoResettable<char>) -> Self {
        self.short_flag = short.into_resettable().into_option();
        self
    }

    /// Sets the long version of the subcommand flag without the preceding `--`.
    ///
    /// Allows the subcommand to be used as if it were an [`Arg::long`].
    ///
    /// **NOTE:** Any leading `-` characters will be stripped.
    ///
    /// # Examples
    ///
    /// To set `long_flag` use a word containing valid UTF-8 codepoints. If you supply a double leading
    /// `--` such as `--sync` they will be stripped. Hyphens in the middle of the word; however,
    /// will *not* be stripped (i.e. `sync-file` is allowed).
    ///
    /// ```
    /// # use clap::{Command, Arg, ArgAction};
    /// let matches = Command::new("pacman")
    ///     .subcommand(
    ///         Command::new("sync").long_flag("sync").arg(
    ///             Arg::new("search")
    ///                 .short('s')
    ///                 .long("search")
    ///                 .action(ArgAction::SetTrue)
    ///                 .help("search remote repositories for matching strings"),
    ///         ),
    ///     )
    ///     .get_matches_from(vec!["pacman", "--sync", "--search"]);
    ///
    /// assert_eq!(matches.subcommand_name().unwrap(), "sync");
    /// let sync_matches = matches.subcommand_matches("sync").unwrap();
    /// assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));
    /// ```
    ///
    /// [`Arg::long`]: Arg::long()
    #[must_use]
    pub fn long_flag(mut self, long: impl Into<Str>) -> Self {
        self.long_flag = Some(long.into());
        self
    }

    /// Sets a hidden alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name, or this given
    /// alias. This is more efficient and easier than creating multiple hidden subcommands as one
    /// only needs to check for the existence of this command, and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If you're looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_alias`]: Command::visible_alias()
    #[must_use]
    pub fn alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, false));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "hidden" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, false));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "hidden" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, false));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple hidden aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the original name or any of the
    /// given aliases. This is more efficient, and easier than creating multiple hidden subcommands
    /// as one only needs to check for the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** Aliases defined with this method are *hidden* from the help
    /// message. If looking for aliases that will be displayed in the help
    /// message, see [`Command::visible_aliases`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .aliases(["do-stuff", "do-tests", "tests"]))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "do-tests"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::visible_aliases`]: Command::visible_aliases()
    #[must_use]
    pub fn aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), false)));
        self
    }

    /// Add aliases, which function as "hidden" short flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test").short_flag('t')
    ///         .short_flag_aliases(['a', 'b', 'c']))
    ///         .arg(Arg::new("input")
    ///             .help("the file to add")
    ///             .required(false))
    ///     .get_matches_from(vec!["myprog", "-a"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, false));
        }
        self
    }

    /// Add aliases, which function as "hidden" long flag subcommands.
    ///
    /// These will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .long_flag_aliases(["testing", "testall", "test_all"]))
    ///                 .arg(Arg::new("input")
    ///                             .help("the file to add")
    ///                             .required(false))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    #[must_use]
    pub fn long_flag_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        for s in names {
            self = self.long_flag_alias(s)
        }
        self
    }

    /// Sets a visible alias to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or the given alias. This is more efficient and easier
    /// than creating hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_alias("do-stuff"))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.aliases.push((name, true));
        } else {
            self.aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as  "visible" short flag subcommand
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::short_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('t')
    ///                 .visible_short_flag_alias('d'))
    ///             .get_matches_from(vec!["myprog", "-d"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_alias`]: Command::short_flag_alias()
    #[must_use]
    pub fn visible_short_flag_alias(mut self, name: impl IntoResettable<char>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            debug_assert!(name != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((name, true));
        } else {
            self.short_flag_aliases.clear();
        }
        self
    }

    /// Add an alias, which functions as a "visible" long flag subcommand.
    ///
    /// This will automatically dispatch as if this subcommand was used. This is more efficient,
    /// and easier than creating multiple hidden subcommands as one only needs to check for the
    /// existence of this command, and not all variants.
    ///
    /// See also [`Command::long_flag_alias`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_alias("testing"))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_alias`]: Command::long_flag_alias()
    #[must_use]
    pub fn visible_long_flag_alias(mut self, name: impl IntoResettable<Str>) -> Self {
        if let Some(name) = name.into_resettable().into_option() {
            self.long_flag_aliases.push((name, true));
        } else {
            self.long_flag_aliases.clear();
        }
        self
    }

    /// Sets multiple visible aliases to this subcommand.
    ///
    /// This allows the subcommand to be accessed via *either* the
    /// original name or any of the given aliases. This is more efficient and easier
    /// than creating multiple hidden subcommands as one only needs to check for
    /// the existence of this command and not all aliased variants.
    ///
    /// **NOTE:** The alias defined with this method is *visible* from the help
    /// message and displayed as if it were just another regular subcommand. If
    /// looking for an alias that will not be displayed in the help message, see
    /// [`Command::alias`].
    ///
    /// **NOTE:** When using aliases, and checking for the existence of a
    /// particular subcommand within an [`ArgMatches`] struct, one only needs to
    /// search for the original name and not all aliases.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///     .subcommand(Command::new("test")
    ///         .visible_aliases(["do-stuff", "tests"]))
    ///     .get_matches_from(vec!["myprog", "do-stuff"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::alias`]: Command::alias()
    #[must_use]
    pub fn visible_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        self.aliases
            .extend(names.into_iter().map(|n| (n.into(), true)));
        self
    }

    /// Add aliases, which function as *visible* short flag subcommands.
    ///
    /// See [`Command::short_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").short_flag('b')
    ///                 .visible_short_flag_aliases(['t']))
    ///             .get_matches_from(vec!["myprog", "-t"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::short_flag_aliases`]: Command::short_flag_aliases()
    #[must_use]
    pub fn visible_short_flag_aliases(mut self, names: impl IntoIterator<Item = char>) -> Self {
        for s in names {
            debug_assert!(s != '-', "short alias name cannot be `-`");
            self.short_flag_aliases.push((s, true));
        }
        self
    }

    /// Add aliases, which function as *visible* long flag subcommands.
    ///
    /// See [`Command::long_flag_aliases`].
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg, };
    /// let m = Command::new("myprog")
    ///             .subcommand(Command::new("test").long_flag("test")
    ///                 .visible_long_flag_aliases(["testing", "testall", "test_all"]))
    ///             .get_matches_from(vec!["myprog", "--testing"]);
    /// assert_eq!(m.subcommand_name(), Some("test"));
    /// ```
    /// [`Command::long_flag_aliases`]: Command::long_flag_aliases()
    #[must_use]
    pub fn visible_long_flag_aliases(
        mut self,
        names: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        for s in names {
            self = self.visible_long_flag_alias(s);
        }
        self
    }

    /// Set the placement of this subcommand within the help.
    ///
    /// Subcommands with a lower value will be displayed first in the help message.  Subcommands
    /// with duplicate display orders will be displayed in alphabetical order.
    ///
    /// This is helpful when one would like to emphasize frequently used subcommands, or prioritize
    /// those towards the top of the list.
    ///
    /// **NOTE:** The default is 999 for all subcommands.
    ///
    /// # Examples
    ///
    #[cfg_attr(not(feature = "help"), doc = " ```ignore")]
    #[cfg_attr(feature = "help", doc = " ```")]
    /// # use clap::{Command, };
    /// let m = Command::new("cust-ord")
    ///     .subcommand(Command::new("alpha") // typically subcommands are grouped
    ///                                                // alphabetically by name. Subcommands
    ///                                                // without a display_order have a value of
    ///                                                // 999 and are displayed alphabetically with
    ///                                                // all other 999 subcommands
    ///         .about("Some help and text"))
    ///     .subcommand(Command::new("beta")
    ///         .display_order(1)   // In order to force this subcommand to appear *first*
    ///                             // all we have to do is give it a value lower than 999.
    ///                             // Any other subcommands with a value of 1 will be displayed
    ///                             // alphabetically with this one...then 2 values, then 3, etc.
    ///         .about("I should be first!"))
    ///     .get_matches_from(vec![
    ///         "cust-ord", "--help"
    ///     ]);
    /// ```
    ///
    /// The above example displays the following help message
    ///
    /// ```text
    /// cust-ord
    ///
    /// Usage: cust-ord [OPTIONS]
    ///
    /// Commands:
    ///     beta    I should be first!
    ///     alpha   Some help and text
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[inline]
    #[must_use]
    pub fn display_order(mut self, ord: impl IntoResettable<usize>) -> Self {
        self.disp_ord = ord.into_resettable().into_option();
        self
    }

    /// Specifies that this [`subcommand`] should be hidden from help messages
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(
    ///         Command::new("test").hide(true)
    ///     )
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    #[inline]
    pub fn hide(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Hidden)
        } else {
            self.unset_setting(AppSettings::Hidden)
        }
    }

    /// If no [`subcommand`] is present at runtime, error and exit gracefully.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_required(true)
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog",
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingSubcommand);
    /// # ;
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    pub fn subcommand_required(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandRequired)
        } else {
            self.unset_setting(AppSettings::SubcommandRequired)
        }
    }

    /// Assume unexpected positional arguments are a [`subcommand`].
    ///
    /// Arguments will be stored in the `""` argument in the [`ArgMatches`]
    ///
    /// **NOTE:** Use this setting with caution,
    /// as a truly unexpected argument (i.e. one that is *NOT* an external subcommand)
    /// will **not** cause an error and instead be treated as a potential subcommand.
    /// One should check for such cases manually and inform the user appropriately.
    ///
    /// **NOTE:** A built-in subcommand will be parsed as an external subcommand when escaped with
    /// `--`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommand`]: crate::Command::subcommand()
    /// [`ArgMatches`]: crate::ArgMatches
    /// [`ErrorKind::UnknownArgument`]: crate::error::ErrorKind::UnknownArgument
    pub fn allow_external_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::AllowExternalSubcommands)
        } else {
            self.unset_setting(AppSettings::AllowExternalSubcommands)
        }
    }

    /// Specifies how to parse external subcommand arguments.
    ///
    /// The default parser is for `OsString`.  This can be used to switch it to `String` or another
    /// type.
    ///
    /// **NOTE:** Setting this requires [`Command::allow_external_subcommands`]
    ///
    /// # Examples
    ///
    #[cfg_attr(not(unix), doc = " ```ignore")]
    #[cfg_attr(unix, doc = " ```")]
    /// # use std::ffi::OsString;
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .allow_external_subcommands(true)
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// ```
    /// # use clap::Command;
    /// # use clap::value_parser;
    /// // Assume there is an external subcommand named "subcmd"
    /// let m = Command::new("myprog")
    ///     .external_subcommand_value_parser(value_parser!(String))
    ///     .get_matches_from(vec![
    ///         "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ///     ]);
    ///
    /// // All trailing arguments will be stored under the subcommand's sub-matches using an empty
    /// // string argument name
    /// match m.subcommand() {
    ///     Some((external, ext_m)) => {
    ///          let ext_args: Vec<_> = ext_m.get_many::<String>("").unwrap().collect();
    ///          assert_eq!(external, "subcmd");
    ///          assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    ///     },
    ///     _ => {},
    /// }
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn external_subcommand_value_parser(
        mut self,
        parser: impl IntoResettable<super::ValueParser>,
    ) -> Self {
        self.external_value_parser = parser.into_resettable().into_option();
        self
    }

    /// Specifies that use of an argument prevents the use of [`subcommands`].
    ///
    /// By default `clap` allows arguments between subcommands such
    /// as `<cmd> [cmd_args] <subcmd> [subcmd_args] <subsubcmd> [subsubcmd_args]`.
    ///
    /// This setting disables that functionality and says that arguments can
    /// only follow the *final* subcommand. For instance using this setting
    /// makes only the following invocations possible:
    ///
    /// * `<cmd> <subcmd> <subsubcmd> [subsubcmd_args]`
    /// * `<cmd> <subcmd> [subcmd_args]`
    /// * `<cmd> [cmd_args]`
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::Command;
    /// Command::new("myprog")
    ///     .args_conflicts_with_subcommands(true);
    /// ```
    ///
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn args_conflicts_with_subcommands(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::ArgsNegateSubcommands)
        } else {
            self.unset_setting(AppSettings::ArgsNegateSubcommands)
        }
    }

    /// Prevent subcommands from being consumed as an arguments value.
    ///
    /// By default, if an option taking multiple values is followed by a subcommand, the
    /// subcommand will be parsed as another value.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   another value
    /// ```
    ///
    /// This setting instructs the parser to stop when encountering a subcommand instead of
    /// greedily consuming arguments.
    ///
    /// ```text
    /// cmd --foo val1 val2 subcommand
    ///           --------- ----------
    ///             values   subcommand
    /// ```
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use clap::{Command, Arg, ArgAction};
    /// let cmd = Command::new("cmd").subcommand(Command::new("sub")).arg(
    ///     Arg::new("arg")
    ///         .long("arg")
    ///         .num_args(1..)
    ///         .action(ArgAction::Set),
    /// );
    ///
    /// let matches = cmd
    ///     .clone()
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3", "sub"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_none());
    ///
    /// let matches = cmd
    ///     .subcommand_precedence_over_arg(true)
    ///     .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    ///     .unwrap();
    /// assert_eq!(
    ///     matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    ///     &["1", "2", "3"]
    /// );
    /// assert!(matches.subcommand_matches("sub").is_some());
    /// ```
    pub fn subcommand_precedence_over_arg(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandPrecedenceOverArg)
        } else {
            self.unset_setting(AppSettings::SubcommandPrecedenceOverArg)
        }
    }

    /// Allows [`subcommands`] to override all requirements of the parent command.
    ///
    /// For example, if you had a subcommand or top level application with a required argument
    /// that is only required as long as there is no subcommand present,
    /// using this setting would allow you to set those arguments to [`Arg::required(true)`]
    /// and yet receive no error so long as the user uses a valid subcommand instead.
    ///
    /// **NOTE:** This defaults to false (using subcommand does *not* negate requirements)
    ///
    /// # Examples
    ///
    /// This first example shows that it is an error to not use a required argument
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let err = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog"
    ///     ]);
    /// assert!(err.is_err());
    /// assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);
    /// # ;
    /// ```
    ///
    /// This next example shows that it is no longer error to not use a required argument if a
    /// valid subcommand is used.
    ///
    /// ```rust
    /// # use clap::{Command, Arg, error::ErrorKind};
    /// let noerr = Command::new("myprog")
    ///     .subcommand_negates_reqs(true)
    ///     .arg(Arg::new("opt").required(true))
    ///     .subcommand(Command::new("test"))
    ///     .try_get_matches_from(vec![
    ///         "myprog", "test"
    ///     ]);
    /// assert!(noerr.is_ok());
    /// # ;
    /// ```
    ///
    /// [`Arg::required(true)`]: crate::Arg::required()
    /// [`subcommands`]: crate::Command::subcommand()
    pub fn subcommand_negates_reqs(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::SubcommandsNegateReqs)
        } else {
            self.unset_setting(AppSettings::SubcommandsNegateReqs)
        }
    }

    /// Multiple-personality program dispatched on the binary name (`argv[0]`)
    ///
    /// A "multicall" executable is a single executable
    /// that contains a variety of applets,
    /// and decides which applet to run based on the name of the file.
    /// The executable can be called from different names by creating hard links
    /// or symbolic links to it.
    ///
    /// This is desirable for:
    /// - Easy distribution, a single binary that can install hardlinks to access the different
    ///   personalities.
    /// - Minimal binary size by sharing common code (e.g. standard library, clap)
    /// - Custom shells or REPLs where there isn't a single top-level command
    ///
    /// Setting `multicall` will cause
    /// - `argv[0]` to be stripped to the base name and parsed as the first argument, as if
    ///   [`Command::no_binary_name`][Command::no_binary_name] was set.
    /// - Help and errors to report subcommands as if they were the top-level command
    ///
    /// When the subcommand is not present, there are several strategies you may employ, depending
    /// on your needs:
    /// - Let the error percolate up normally
    /// - Print a specialized error message using the
    ///   [`Error::context`][crate::Error::context]
    /// - Print the [help][Command::write_help] but this might be ambiguous
    /// - Disable `multicall` and re-parse it
    /// - Disable `multicall` and re-parse it with a specific subcommand
    ///
    /// When detecting the error condition, the [`ErrorKind`] isn't sufficient as a sub-subcommand
    /// might report the same error.  Enable
    /// [`allow_external_subcommands`][Command::allow_external_subcommands] if you want to specifically
    /// get the unrecognized binary name.
    ///
    /// **NOTE:** Multicall can't be used with [`no_binary_name`] since they interpret
    /// the command name in incompatible ways.
    ///
    /// **NOTE:** The multicall command cannot have arguments.
    ///
    /// **NOTE:** Applets are slightly semantically different from subcommands,
    /// so it's recommended to use [`Command::subcommand_help_heading`] and
    /// [`Command::subcommand_value_name`] to change the descriptive text as above.
    ///
    /// # Examples
    ///
    /// `hostname` is an example of a multicall executable.
    /// Both `hostname` and `dnsdomainname` are provided by the same executable
    /// and which behaviour to use is based on the executable file name.
    ///
    /// This is desirable when the executable has a primary purpose
    /// but there is related functionality that would be convenient to provide
    /// and implement it to be in the same executable.
    ///
    /// The name of the cmd is essentially unused
    /// and may be the same as the name of a subcommand.
    ///
    /// The names of the immediate subcommands of the Command
    /// are matched against the basename of the first argument,
    /// which is conventionally the path of the executable.
    ///
    /// This does not allow the subcommand to be passed as the first non-path argument.
    ///
    /// ```rust
    /// # use clap::{Command, error::ErrorKind};
    /// let mut cmd = Command::new("hostname")
    ///     .multicall(true)
    ///     .subcommand(Command::new("hostname"))
    ///     .subcommand(Command::new("dnsdomainname"));
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/hostname", "dnsdomainname"]);
    /// assert!(m.is_err());
    /// assert_eq!(m.unwrap_err().kind(), ErrorKind::UnknownArgument);
    /// let m = cmd.get_matches_from(&["/usr/bin/dnsdomainname"]);
    /// assert_eq!(m.subcommand_name(), Some("dnsdomainname"));
    /// ```
    ///
    /// Busybox is another common example of a multicall executable
    /// with a subcommmand for each applet that can be run directly,
    /// e.g. with the `cat` applet being run by running `busybox cat`,
    /// or with `cat` as a link to the `busybox` binary.
    ///
    /// This is desirable when the launcher program has additional options
    /// or it is useful to run the applet without installing a symlink
    /// e.g. to test the applet without installing it
    /// or there may already be a command of that name installed.
    ///
    /// To make an applet usable as both a multicall link and a subcommand
    /// the subcommands must be defined both in the top-level Command
    /// and as subcommands of the "main" applet.
    ///
    /// ```rust
    /// # use clap::Command;
    /// fn applet_commands() -> [Command; 2] {
    ///     [Command::new("true"), Command::new("false")]
    /// }
    /// let mut cmd = Command::new("busybox")
    ///     .multicall(true)
    ///     .subcommand(
    ///         Command::new("busybox")
    ///             .subcommand_value_name("APPLET")
    ///             .subcommand_help_heading("APPLETS")
    ///             .subcommands(applet_commands()),
    ///     )
    ///     .subcommands(applet_commands());
    /// // When called from the executable's canonical name
    /// // its applets can be matched as subcommands.
    /// let m = cmd.try_get_matches_from_mut(&["/usr/bin/busybox", "true"]).unwrap();
    /// assert_eq!(m.subcommand_name(), Some("busybox"));
    /// assert_eq!(m.subcommand().unwrap().1.subcommand_name(), Some("true"));
    /// // When called from a link named after an applet that applet is matched.
    /// let m = cmd.get_matches_from(&["/usr/bin/true"]);
    /// assert_eq!(m.subcommand_name(), Some("true"));
    /// ```
    ///
    /// [`no_binary_name`]: crate::Command::no_binary_name
    /// [`Command::subcommand_value_name`]: crate::Command::subcommand_value_name
    /// [`Command::subcommand_help_heading`]: crate::Command::subcommand_help_heading
    #[inline]
    pub fn multicall(self, yes: bool) -> Self {
        if yes {
            self.setting(AppSettings::Multicall)
        } else {
            self.unset_setting(AppSettings::Multicall)
        }
    }

    /// Sets the value name used for subcommands when printing usage and help.
    ///
    /// By default, this is "COMMAND".
    ///
    /// See also [`Command::subcommand_help_heading`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_value_name`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_value_name("THING")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [THING]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_value_name(mut self, value_name: impl IntoResettable<Str>) -> Self {
        self.subcommand_value_name = value_name.into_resettable().into_option();
        self
    }

    /// Sets the help heading used for subcommands when printing usage and help.
    ///
    /// By default, this is "Commands".
    ///
    /// See also [`Command::subcommand_value_name`]
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Commands:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    ///
    /// but usage of `subcommand_help_heading`
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// Command::new("myprog")
    ///     .subcommand(Command::new("sub1"))
    ///     .subcommand_help_heading("Things")
    ///     .print_help()
    /// # ;
    /// ```
    ///
    /// will produce
    ///
    /// ```text
    /// myprog
    ///
    /// Usage: myprog [COMMAND]
    ///
    /// Things:
    ///     help    Print this message or the help of the given subcommand(s)
    ///     sub1
    ///
    /// Options:
    ///     -h, --help       Print help information
    ///     -V, --version    Print version information
    /// ```
    #[must_use]
    pub fn subcommand_help_heading(mut self, heading: impl IntoResettable<Str>) -> Self {
        self.subcommand_heading = heading.into_resettable().into_option();
        self
    }
}

/// # Reflection
impl Command {
    #[inline]
    #[cfg(feature = "usage")]
    pub(crate) fn get_usage_name(&self) -> Option<&str> {
        self.usage_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_display_name(&self) -> Option<&str> {
        self.display_name.as_deref()
    }

    /// Get the name of the binary.
    #[inline]
    pub fn get_bin_name(&self) -> Option<&str> {
        self.bin_name.as_deref()
    }

    /// Set binary name. Uses `&mut self` instead of `self`.
    pub fn set_bin_name(&mut self, name: impl Into<String>) {
        self.bin_name = Some(name.into());
    }

    /// Get the name of the cmd.
    #[inline]
    pub fn get_name(&self) -> &str {
        self.name.as_str()
    }

    #[inline]
    #[cfg(debug_assertions)]
    pub(crate) fn get_name_str(&self) -> &Str {
        &self.name
    }

    /// Get the version of the cmd.
    #[inline]
    pub fn get_version(&self) -> Option<&str> {
        self.version.as_deref()
    }

    /// Get the long version of the cmd.
    #[inline]
    pub fn get_long_version(&self) -> Option<&str> {
        self.long_version.as_deref()
    }

    /// Get the authors of the cmd.
    #[inline]
    pub fn get_author(&self) -> Option<&str> {
        self.author.as_deref()
    }

    /// Get the short flag of the subcommand.
    #[inline]
    pub fn get_short_flag(&self) -> Option<char> {
        self.short_flag
    }

    /// Get the long flag of the subcommand.
    #[inline]
    pub fn get_long_flag(&self) -> Option<&str> {
        self.long_flag.as_deref()
    }

    /// Get the help message specified via [`Command::about`].
    ///
    /// [`Command::about`]: Command::about()
    #[inline]
    pub fn get_about(&self) -> Option<&StyledStr> {
        self.about.as_ref()
    }

    /// Get the help message specified via [`Command::long_about`].
    ///
    /// [`Command::long_about`]: Command::long_about()
    #[inline]
    pub fn get_long_about(&self) -> Option<&StyledStr> {
        self.long_about.as_ref()
    }

    /// Get the custom section heading specified via [`Command::next_help_heading`].
    ///
    /// [`Command::help_heading`]: Command::help_heading()
    #[inline]
    pub fn get_next_help_heading(&self) -> Option<&str> {
        self.current_help_heading.as_deref()
    }

    /// Iterate through the *visible* aliases for this subcommand.
    #[inline]
    pub fn get_visible_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the *visible* short aliases for this subcommand.
    #[inline]
    pub fn get_visible_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0)
    }

    /// Iterate through the *visible* long aliases for this subcommand.
    #[inline]
    pub fn get_visible_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases
            .iter()
            .filter(|(_, vis)| *vis)
            .map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.aliases.iter().map(|a| a.0.as_str())
    }

    /// Iterate through the set of *all* the short aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_short_flag_aliases(&self) -> impl Iterator<Item = char> + '_ {
        self.short_flag_aliases.iter().map(|a| a.0)
    }

    /// Iterate through the set of *all* the long aliases for this subcommand, both visible and hidden.
    #[inline]
    pub fn get_all_long_flag_aliases(&self) -> impl Iterator<Item = &str> + '_ {
        self.long_flag_aliases.iter().map(|a| a.0.as_str())
    }

    #[inline]
    pub(crate) fn is_set(&self, s: AppSettings) -> bool {
        self.settings.is_set(s) || self.g_settings.is_set(s)
    }

    /// Should we color the output?
    pub fn get_color(&self) -> ColorChoice {
        debug!("Command::color: Color setting...");

        if cfg!(feature = "color") {
            if self.is_set(AppSettings::ColorNever) {
                debug!("Never");
                ColorChoice::Never
            } else if self.is_set(AppSettings::ColorAlways) {
                debug!("Always");
                ColorChoice::Always
            } else {
                debug!("Auto");
                ColorChoice::Auto
            }
        } else {
            ColorChoice::Never
        }
    }

    /// Iterate through the set of subcommands, getting a reference to each.
    #[inline]
    pub fn get_subcommands(&self) -> impl Iterator<Item = &Command> {
        self.subcommands.iter()
    }

    /// Iterate through the set of subcommands, getting a mutable reference to each.
    #[inline]
    pub fn get_subcommands_mut(&mut self) -> impl Iterator<Item = &mut Command> {
        self.subcommands.iter_mut()
    }

    /// Returns `true` if this `Command` has subcommands.
    #[inline]
    pub fn has_subcommands(&self) -> bool {
        !self.subcommands.is_empty()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_subcommand_help_heading(&self) -> Option<&str> {
        self.subcommand_heading.as_deref()
    }

    /// Returns the subcommand value name.
    #[inline]
    pub fn get_subcommand_value_name(&self) -> Option<&str> {
        self.subcommand_value_name.as_deref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_help(&self) -> Option<&StyledStr> {
        self.before_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_before_long_help(&self) -> Option<&StyledStr> {
        self.before_long_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_help(&self) -> Option<&StyledStr> {
        self.after_help.as_ref()
    }

    /// Returns the help heading for listing subcommands.
    #[inline]
    pub fn get_after_long_help(&self) -> Option<&StyledStr> {
        self.after_long_help.as_ref()
    }

    /// Find subcommand such that its name or one of aliases equals `name`.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand(&self, name: impl AsRef<std::ffi::OsStr>) -> Option<&Command> {
        let name = name.as_ref();
        self.get_subcommands().find(|s| s.aliases_to(name))
    }

    /// Find subcommand such that its name or one of aliases equals `name`, returning
    /// a mutable reference to the subcommand.
    ///
    /// This does not recurse through subcommands of subcommands.
    #[inline]
    pub fn find_subcommand_mut(
        &mut self,
        name: impl AsRef<std::ffi::OsStr>,
    ) -> Option<&mut Command> {
        let name = name.as_ref();
        self.get_subcommands_mut().find(|s| s.aliases_to(name))
    }

    /// Iterate through the set of groups.
    #[inline]
    pub fn get_groups(&self) -> impl Iterator<Item = &ArgGroup> {
        self.groups.iter()
    }

    /// Iterate through the set of arguments.
    #[inline]
    pub fn get_arguments(&self) -> impl Iterator<Item = &Arg> {
        self.args.args()
    }

    /// Iterate through the *positionals* arguments.
    #[inline]
    pub fn get_positionals(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments().filter(|a| a.is_positional())
    }

    /// Iterate through the *options*.
    pub fn get_opts(&self) -> impl Iterator<Item = &Arg> {
        self.get_arguments()
            .filter(|a| a.is_takes_value_set() && !a.is_positional())
    }

    /// Get a list of all arguments the given argument conflicts with.
    ///
    /// If the provided argument is declared as global, the conflicts will be determined
    /// based on the propagation rules of global arguments.
    ///
    /// ### Panics
    ///
    /// If the given arg contains a conflict with an argument that is unknown to
    /// this `Command`.
    pub fn get_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        if arg.is_global_set() {
            self.get_global_arg_conflicts_with(arg)
        } else {
            let mut result = Vec::new();
            for id in arg.blacklist.iter() {
                if let Some(arg) = self.find(id) {
                    result.push(arg);
                } else if let Some(group) = self.find_group(id) {
                    result.extend(
                        self.unroll_args_in_group(&group.id)
                            .iter()
                            .map(|id| self.find(id).expect(INTERNAL_ERROR_MSG)),
                    );
                } else {
                    panic!("Command::get_arg_conflicts_with: The passed arg conflicts with an arg unknown to the cmd");
                }
            }
            result
        }
    }

    // Get a unique list of all arguments of all commands and continuous subcommands the given argument conflicts with.
    //
    // This behavior follows the propagation rules of global arguments.
    // It is useful for finding conflicts for arguments declared as global.
    //
    // ### Panics
    //
    // If the given arg contains a conflict with an argument that is unknown to
    // this `Command`.
    fn get_global_arg_conflicts_with(&self, arg: &Arg) -> Vec<&Arg> // FIXME: This could probably have been an iterator
    {
        arg.blacklist
            .iter()
            .map(|id| {
                self.args
                    .args()
                    .chain(
                        self.get_subcommands_containing(arg)
                            .iter()
                            .flat_map(|x| x.args.args()),
                    )
                    .find(|arg| arg.get_id() == id)
                    .expect(
                        "Command::get_arg_conflicts_with: \
                    The passed arg conflicts with an arg unknown to the cmd",
                    )
            })
            .collect()
    }

    // Get a list of subcommands which contain the provided Argument
    //
    // This command will only include subcommands in its list for which the subcommands
    // parent also contains the Argument.
    //
    // This search follows the propagation rules of global arguments.
    // It is useful to finding subcommands, that have inherited a global argument.
    //
    // **NOTE:** In this case only Sucommand_1 will be included
    //   Subcommand_1 (contains Arg)
    //     Subcommand_1.1 (doesn't contain Arg)
    //       Subcommand_1.1.1 (contains Arg)
    //
    fn get_subcommands_containing(&self, arg: &Arg) -> Vec<&Self> {
        let mut vec = std::vec::Vec::new();
        for idx in 0..self.subcommands.len() {
            if self.subcommands[idx]
                .args
                .args()
                .any(|ar| ar.get_id() == arg.get_id())
            {
                vec.push(&self.subcommands[idx]);
                vec.append(&mut self.subcommands[idx].get_subcommands_containing(arg));
            }
        }
        vec
    }

    /// Report whether [`Command::no_binary_name`] is set
    pub fn is_no_binary_name_set(&self) -> bool {
        self.is_set(AppSettings::NoBinaryName)
    }

    /// Report whether [`Command::ignore_errors`] is set
    pub(crate) fn is_ignore_errors_set(&self) -> bool {
        self.is_set(AppSettings::IgnoreErrors)
    }

    /// Report whether [`Command::dont_delimit_trailing_values`] is set
    pub fn is_dont_delimit_trailing_values_set(&self) -> bool {
        self.is_set(AppSettings::DontDelimitTrailingValues)
    }

    /// Report whether [`Command::disable_version_flag`] is set
    pub fn is_disable_version_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableVersionFlag)
            || (self.version.is_none() && self.long_version.is_none())
    }

    /// Report whether [`Command::propagate_version`] is set
    pub fn is_propagate_version_set(&self) -> bool {
        self.is_set(AppSettings::PropagateVersion)
    }

    /// Report whether [`Command::next_line_help`] is set
    pub fn is_next_line_help_set(&self) -> bool {
        self.is_set(AppSettings::NextLineHelp)
    }

    /// Report whether [`Command::disable_help_flag`] is set
    pub fn is_disable_help_flag_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpFlag)
    }

    /// Report whether [`Command::disable_help_subcommand`] is set
    pub fn is_disable_help_subcommand_set(&self) -> bool {
        self.is_set(AppSettings::DisableHelpSubcommand)
    }

    /// Report whether [`Command::disable_colored_help`] is set
    pub fn is_disable_colored_help_set(&self) -> bool {
        self.is_set(AppSettings::DisableColoredHelp)
    }

    /// Report whether [`Command::help_expected`] is set
    #[cfg(debug_assertions)]
    pub(crate) fn is_help_expected_set(&self) -> bool {
        self.is_set(AppSettings::HelpExpected)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "This is now the default")
    )]
    pub fn is_dont_collapse_args_in_usage_set(&self) -> bool {
        true
    }

    /// Report whether [`Command::infer_long_args`] is set
    pub(crate) fn is_infer_long_args_set(&self) -> bool {
        self.is_set(AppSettings::InferLongArgs)
    }

    /// Report whether [`Command::infer_subcommands`] is set
    pub(crate) fn is_infer_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::InferSubcommands)
    }

    /// Report whether [`Command::arg_required_else_help`] is set
    pub fn is_arg_required_else_help_set(&self) -> bool {
        self.is_set(AppSettings::ArgRequiredElseHelp)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_hyphen_values_set`"
        )
    )]
    pub(crate) fn is_allow_hyphen_values_set(&self) -> bool {
        self.is_set(AppSettings::AllowHyphenValues)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(
            since = "4.0.0",
            note = "Replaced with `Arg::is_allow_negative_numbers_set`"
        )
    )]
    pub fn is_allow_negative_numbers_set(&self) -> bool {
        self.is_set(AppSettings::AllowNegativeNumbers)
    }

    #[doc(hidden)]
    #[cfg_attr(
        feature = "deprecated",
        deprecated(since = "4.0.0", note = "Replaced with `Arg::is_trailing_var_arg_set`")
    )]
    pub fn is_trailing_var_arg_set(&self) -> bool {
        self.is_set(AppSettings::TrailingVarArg)
    }

    /// Report whether [`Command::allow_missing_positional`] is set
    pub fn is_allow_missing_positional_set(&self) -> bool {
        self.is_set(AppSettings::AllowMissingPositional)
    }

    /// Report whether [`Command::hide`] is set
    pub fn is_hide_set(&self) -> bool {
        self.is_set(AppSettings::Hidden)
    }

    /// Report whether [`Command::subcommand_required`] is set
    pub fn is_subcommand_required_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandRequired)
    }

    /// Report whether [`Command::allow_external_subcommands`] is set
    pub fn is_allow_external_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::AllowExternalSubcommands)
    }

    /// Configured parser for values passed to an external subcommand
    ///
    /// # Example
    ///
    /// ```rust
    /// let cmd = clap::Command::new("raw")
    ///     .external_subcommand_value_parser(clap::value_parser!(String));
    /// let value_parser = cmd.get_external_subcommand_value_parser();
    /// println!("{:?}", value_parser);
    /// ```
    pub fn get_external_subcommand_value_parser(&self) -> Option<&super::ValueParser> {
        if !self.is_allow_external_subcommands_set() {
            None
        } else {
            static DEFAULT: super::ValueParser = super::ValueParser::os_string();
            Some(self.external_value_parser.as_ref().unwrap_or(&DEFAULT))
        }
    }

    /// Report whether [`Command::args_conflicts_with_subcommands`] is set
    pub fn is_args_conflicts_with_subcommands_set(&self) -> bool {
        self.is_set(AppSettings::ArgsNegateSubcommands)
    }

    #[doc(hidden)]
    pub fn is_args_override_self(&self) -> bool {
        self.is_set(AppSettings::AllArgsOverrideSelf)
    }

    /// Report whether [`Command::subcommand_precedence_over_arg`] is set
    pub fn is_subcommand_precedence_over_arg_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandPrecedenceOverArg)
    }

    /// Report whether [`Command::subcommand_negates_reqs`] is set
    pub fn is_subcommand_negates_reqs_set(&self) -> bool {
        self.is_set(AppSettings::SubcommandsNegateReqs)
    }

    /// Report whether [`Command::multicall`] is set
    pub fn is_multicall_set(&self) -> bool {
        self.is_set(AppSettings::Multicall)
    }
}

// Internally used only
impl Command {
    pub(crate) fn get_override_usage(&self) -> Option<&StyledStr> {
        self.usage_str.as_ref()
    }

    pub(crate) fn get_override_help(&self) -> Option<&StyledStr> {
        self.help_str.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_help_template(&self) -> Option<&StyledStr> {
        self.template.as_ref()
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_term_width(&self) -> Option<usize> {
        self.term_w
    }

    #[cfg(feature = "help")]
    pub(crate) fn get_max_term_width(&self) -> Option<usize> {
        self.max_w
    }

    pub(crate) fn get_replacement(&self, key: &str) -> Option<&[Str]> {
        self.replacers.get(key).map(|v| v.as_slice())
    }

    pub(crate) fn get_keymap(&self) -> &MKeyMap {
        &self.args
    }

    fn get_used_global_args(&self, matches: &ArgMatches, global_arg_vec: &mut Vec<Id>) {
        global_arg_vec.extend(
            self.args
                .args()
                .filter(|a| a.is_global_set())
                .map(|ga| ga.id.clone()),
        );
        if let Some((id, matches)) = matches.subcommand() {
            if let Some(used_sub) = self.find_subcommand(id) {
                used_sub.get_used_global_args(matches, global_arg_vec);
            }
        }
    }

    fn _do_parse(
        &mut self,
        raw_args: &mut clap_lex::RawArgs,
        args_cursor: clap_lex::ArgCursor,
    ) -> ClapResult<ArgMatches> {
        debug!("Command::_do_parse");

        // If there are global arguments, or settings we need to propagate them down to subcommands
        // before parsing in case we run into a subcommand
        self._build_self(false);

        let mut matcher = ArgMatcher::new(self);

        // do the real parsing
        let mut parser = Parser::new(self);
        if let Err(error) = parser.get_matches_with(&mut matcher, raw_args, args_cursor) {
            if self.is_set(AppSettings::IgnoreErrors) {
                debug!("Command::_do_parse: ignoring error: {}", error);
            } else {
                return Err(error);
            }
        }

        let mut global_arg_vec = Default::default();
        self.get_used_global_args(&matcher, &mut global_arg_vec);

        matcher.propagate_globals(&global_arg_vec);

        Ok(matcher.into_inner())
    }

    /// Prepare for introspecting on all included [`Command`]s
    ///
    /// Call this on the top-level [`Command`] when done building and before reading state for
    /// cases like completions, custom help output, etc.
    pub fn build(&mut self) {
        self._build_recursive(true);
        self._build_bin_names_internal();
    }

    pub(crate) fn _build_recursive(&mut self, expand_help_tree: bool) {
        self._build_self(expand_help_tree);
        for subcmd in self.get_subcommands_mut() {
            subcmd._build_recursive(expand_help_tree);
        }
    }

    pub(crate) fn _build_self(&mut self, expand_help_tree: bool) {
        debug!("Command::_build: name={:?}", self.get_name());
        if !self.settings.is_set(AppSettings::Built) {
            // Make sure all the globally set flags apply to us as well
            self.settings = self.settings | self.g_settings;

            if self.is_multicall_set() {
                self.settings.insert(AppSettings::SubcommandRequired.into());
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings.insert(AppSettings::DisableVersionFlag.into());
            }
            if !cfg!(feature = "help") && self.get_override_help().is_none() {
                self.settings.insert(AppSettings::DisableHelpFlag.into());
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }
            if self.is_set(AppSettings::ArgsNegateSubcommands) {
                self.settings
                    .insert(AppSettings::SubcommandsNegateReqs.into());
            }
            if self.external_value_parser.is_some() {
                self.settings
                    .insert(AppSettings::AllowExternalSubcommands.into());
            }
            if !self.has_subcommands() {
                self.settings
                    .insert(AppSettings::DisableHelpSubcommand.into());
            }

            self._propagate();
            self._check_help_and_version(expand_help_tree);
            self._propagate_global_args();

            let mut pos_counter = 1;
            let hide_pv = self.is_set(AppSettings::HidePossibleValues);
            for a in self.args.args_mut() {
                // Fill in the groups
                for g in &a.groups {
                    if let Some(ag) = self.groups.iter_mut().find(|grp| grp.id == *g) {
                        ag.args.push(a.get_id().clone());
                    } else {
                        let mut ag = ArgGroup::new(g);
                        ag.args.push(a.get_id().clone());
                        self.groups.push(ag);
                    }
                }

                // Figure out implied settings
                a._build();
                if hide_pv && a.is_takes_value_set() {
                    a.settings.set(ArgSettings::HidePossibleValues);
                }
                if a.is_positional() && a.index.is_none() {
                    a.index = Some(pos_counter);
                    pos_counter += 1;
                }
            }

            self.args._build();

            #[allow(deprecated)]
            {
                let highest_idx = self
                    .get_keymap()
                    .keys()
                    .filter_map(|x| {
                        if let crate::mkeymap::KeyType::Position(n) = x {
                            Some(*n)
                        } else {
                            None
                        }
                    })
                    .max()
                    .unwrap_or(0);
                let is_trailing_var_arg_set = self.is_trailing_var_arg_set();
                let is_allow_hyphen_values_set = self.is_allow_hyphen_values_set();
                let is_allow_negative_numbers_set = self.is_allow_negative_numbers_set();
                for arg in self.args.args_mut() {
                    if is_allow_hyphen_values_set && arg.is_takes_value_set() {
                        arg.settings.insert(ArgSettings::AllowHyphenValues.into());
                    }
                    if is_allow_negative_numbers_set && arg.is_takes_value_set() {
                        arg.settings
                            .insert(ArgSettings::AllowNegativeNumbers.into());
                    }
                    if is_trailing_var_arg_set && arg.get_index() == Some(highest_idx) {
                        arg.settings.insert(ArgSettings::TrailingVarArg.into());
                    }
                }
            }

            #[cfg(debug_assertions)]
            assert_app(self);
            self.settings.set(AppSettings::Built);
        } else {
            debug!("Command::_build: already built");
        }
    }

    pub(crate) fn _build_subcommand(&mut self, name: &str) -> Option<&mut Self> {
        use std::fmt::Write;

        let mut mid_string = String::from(" ");
        #[cfg(feature = "usage")]
        if !self.is_subcommand_negates_reqs_set() && !self.is_args_conflicts_with_subcommands_set()
        {
            let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

            for s in &reqs {
                mid_string.push_str(&s.to_string());
                mid_string.push(' ');
            }
        }
        let is_multicall_set = self.is_multicall_set();

        let sc = some!(self.subcommands.iter_mut().find(|s| s.name == name));

        // Display subcommand name, short and long in usage
        let mut sc_names = String::new();
        sc_names.push_str(sc.name.as_str());
        let mut flag_subcmd = false;
        if let Some(l) = sc.get_long_flag() {
            write!(sc_names, "|--{}", l).unwrap();
            flag_subcmd = true;
        }
        if let Some(s) = sc.get_short_flag() {
            write!(sc_names, "|-{}", s).unwrap();
            flag_subcmd = true;
        }

        if flag_subcmd {
            sc_names = format!("{{{}}}", sc_names);
        }

        let usage_name = self
            .bin_name
            .as_ref()
            .map(|bin_name| format!("{}{}{}", bin_name, mid_string, sc_names))
            .unwrap_or(sc_names);
        sc.usage_name = Some(usage_name);

        // bin_name should be parent's bin_name + [<reqs>] + the sc's name separated by
        // a space
        let bin_name = format!(
            "{}{}{}",
            self.bin_name.as_deref().unwrap_or_default(),
            if self.bin_name.is_some() { " " } else { "" },
            &*sc.name
        );
        debug!(
            "Command::_build_subcommand Setting bin_name of {} to {:?}",
            sc.name, bin_name
        );
        sc.bin_name = Some(bin_name);

        if sc.display_name.is_none() {
            let self_display_name = if is_multicall_set {
                self.display_name.as_deref().unwrap_or("")
            } else {
                self.display_name.as_deref().unwrap_or(&self.name)
            };
            let display_name = format!(
                "{}{}{}",
                self_display_name,
                if !self_display_name.is_empty() {
                    "-"
                } else {
                    ""
                },
                &*sc.name
            );
            debug!(
                "Command::_build_subcommand Setting display_name of {} to {:?}",
                sc.name, display_name
            );
            sc.display_name = Some(display_name);
        }

        // Ensure all args are built and ready to parse
        sc._build_self(false);

        Some(sc)
    }

    fn _build_bin_names_internal(&mut self) {
        debug!("Command::_build_bin_names");

        if !self.is_set(AppSettings::BinNameBuilt) {
            let mut mid_string = String::from(" ");
            #[cfg(feature = "usage")]
            if !self.is_subcommand_negates_reqs_set()
                && !self.is_args_conflicts_with_subcommands_set()
            {
                let reqs = Usage::new(self).get_required_usage_from(&[], None, true); // maybe Some(m)

                for s in &reqs {
                    mid_string.push_str(&s.to_string());
                    mid_string.push(' ');
                }
            }
            let is_multicall_set = self.is_multicall_set();

            let self_bin_name = if is_multicall_set {
                self.bin_name.as_deref().unwrap_or("")
            } else {
                self.bin_name.as_deref().unwrap_or(&self.name)
            }
            .to_owned();

            for mut sc in &mut self.subcommands {
                debug!("Command::_build_bin_names:iter: bin_name set...");

                if sc.usage_name.is_none() {
                    use std::fmt::Write;
                    // Display subcommand name, short and long in usage
                    let mut sc_names = String::new();
                    sc_names.push_str(sc.name.as_str());
                    let mut flag_subcmd = false;
                    if let Some(l) = sc.get_long_flag() {
                        write!(sc_names, "|--{}", l).unwrap();
                        flag_subcmd = true;
                    }
                    if let Some(s) = sc.get_short_flag() {
                        write!(sc_names, "|-{}", s).unwrap();
                        flag_subcmd = true;
                    }

                    if flag_subcmd {
                        sc_names = format!("{{{}}}", sc_names);
                    }

                    let usage_name = format!("{}{}{}", self_bin_name, mid_string, sc_names);
                    debug!(
                        "Command::_build_bin_names:iter: Setting usage_name of {} to {:?}",
                        sc.name, usage_name
                    );
                    sc.usage_name = Some(usage_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing usage_name of {} ({:?})",
                        sc.name, sc.usage_name
                    );
                }

                if sc.bin_name.is_none() {
                    let bin_name = format!(
                        "{}{}{}",
                        self_bin_name,
                        if !self_bin_name.is_empty() { " " } else { "" },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting bin_name of {} to {:?}",
                        sc.name, bin_name
                    );
                    sc.bin_name = Some(bin_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing bin_name of {} ({:?})",
                        sc.name, sc.bin_name
                    );
                }

                if sc.display_name.is_none() {
                    let self_display_name = if is_multicall_set {
                        self.display_name.as_deref().unwrap_or("")
                    } else {
                        self.display_name.as_deref().unwrap_or(&self.name)
                    };
                    let display_name = format!(
                        "{}{}{}",
                        self_display_name,
                        if !self_display_name.is_empty() {
                            "-"
                        } else {
                            ""
                        },
                        &*sc.name
                    );
                    debug!(
                        "Command::_build_bin_names:iter: Setting display_name of {} to {:?}",
                        sc.name, display_name
                    );
                    sc.display_name = Some(display_name);
                } else {
                    debug!(
                        "Command::_build_bin_names::iter: Using existing display_name of {} ({:?})",
                        sc.name, sc.display_name
                    );
                }

                sc._build_bin_names_internal();
            }
            self.set(AppSettings::BinNameBuilt);
        } else {
            debug!("Command::_build_bin_names: already built");
        }
    }

    pub(crate) fn _panic_on_missing_help(&self, help_required_globally: bool) {
        if self.is_set(AppSettings::HelpExpected) || help_required_globally {
            let args_missing_help: Vec<Id> = self
                .args
                .args()
                .filter(|arg| arg.get_help().is_none() && arg.get_long_help().is_none())
                .map(|arg| arg.get_id().clone())
                .collect();

            debug_assert!(args_missing_help.is_empty(),
                    "Command::help_expected is enabled for the Command {}, but at least one of its arguments does not have either `help` or `long_help` set. List of such arguments: {}",
                    self.name,
                    args_missing_help.join(", ")
                );
        }

        for sub_app in &self.subcommands {
            sub_app._panic_on_missing_help(help_required_globally);
        }
    }

    #[cfg(debug_assertions)]
    pub(crate) fn two_args_of<F>(&self, condition: F) -> Option<(&Arg, &Arg)>
    where
        F: Fn(&Arg) -> bool,
    {
        two_elements_of(self.args.args().filter(|a: &&Arg| condition(a)))
    }

    // just in case
    #[allow(unused)]
    fn two_groups_of<F>(&self, condition: F) -> Option<(&ArgGroup, &ArgGroup)>
    where
        F: Fn(&ArgGroup) -> bool,
    {
        two_elements_of(self.groups.iter().filter(|a| condition(a)))
    }

    /// Propagate global args
    pub(crate) fn _propagate_global_args(&mut self) {
        debug!("Command::_propagate_global_args:{}", self.name);

        let autogenerated_help_subcommand = !self.is_disable_help_subcommand_set();

        for sc in &mut self.subcommands {
            if sc.get_name() == "help" && autogenerated_help_subcommand {
                // Avoid propagating args to the autogenerated help subtrees used in completion.
                // This prevents args from showing up during help completions like
                // `myapp help subcmd <TAB>`, which should only suggest subcommands and not args,
                // while still allowing args to show up properly on the generated help message.
                continue;
            }

            for a in self.args.args().filter(|a| a.is_global_set()) {
                if sc.find(&a.id).is_some() {
                    debug!(
                        "Command::_propagate skipping {:?} to {}, already exists",
                        a.id,
                        sc.get_name(),
                    );
                    continue;
                }

                debug!(
                    "Command::_propagate pushing {:?} to {}",
                    a.id,
                    sc.get_name(),
                );
                sc.args.push(a.clone());
            }
        }
    }

    /// Propagate settings
    pub(crate) fn _propagate(&mut self) {
        debug!("Command::_propagate:{}", self.name);
        let mut subcommands = std::mem::take(&mut self.subcommands);
        for sc in &mut subcommands {
            self._propagate_subcommand(sc);
        }
        self.subcommands = subcommands;
    }

    fn _propagate_subcommand(&self, sc: &mut Self) {
        // We have to create a new scope in order to tell rustc the borrow of `sc` is
        // done and to recursively call this method
        {
            if self.settings.is_set(AppSettings::PropagateVersion) {
                if let Some(version) = self.version.as_ref() {
                    sc.version.get_or_insert_with(|| version.clone());
                }
                if let Some(long_version) = self.long_version.as_ref() {
                    sc.long_version.get_or_insert_with(|| long_version.clone());
                }
            }

            sc.settings = sc.settings | self.g_settings;
            sc.g_settings = sc.g_settings | self.g_settings;
            sc.term_w = self.term_w;
            sc.max_w = self.max_w;
        }
    }

    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

Adds multiple subcommands to the list of valid possibilities.

Examples
.subcommands( [
       Command::new("config").about("Controls configuration functionality")
                                .arg(Arg::new("config_file")),
       Command::new("debug").about("Controls debug functionality")])
Examples found in repository?
src/builder/command.rs (line 4276)
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    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

Catch problems earlier in the development cycle.

Most error states are handled as asserts under the assumption they are programming mistake and not something to handle at runtime. Rather than relying on tests (manual or automated) that exhaustively test your CLI to ensure the asserts are evaluated, this will run those asserts in a way convenient for running as a test.

Note:: This will not help with asserts in ArgMatches, those will need exhaustive testing of your CLI.

Examples
fn cmd() -> Command {
    Command::new("foo")
        .arg(
            Arg::new("bar").short('b').action(ArgAction::SetTrue)
        )
}

#[test]
fn verify_app() {
    cmd().debug_assert();
}

fn main() {
    let m = cmd().get_matches_from(vec!["foo", "-b"]);
    println!("{}", *m.get_one::<bool>("bar").expect("defaulted by clap"));
}

Custom error message for post-parsing validation

Examples
let mut cmd = Command::new("myprog");
let err = cmd.error(ErrorKind::InvalidValue, "Some failure case");

Parse env::args_os, exiting on failure.

Panics

If contradictory arguments or settings exist.

Examples
let matches = Command::new("myprog")
    // Args and options go here...
    .get_matches();
Examples found in repository?
src/derive.rs (line 82)
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    fn parse() -> Self {
        let mut matches = <Self as CommandFactory>::command().get_matches();
        let res = <Self as FromArgMatches>::from_arg_matches_mut(&mut matches)
            .map_err(format_error::<Self>);
        match res {
            Ok(s) => s,
            Err(e) => {
                // Since this is more of a development-time error, we aren't doing as fancy of a quit
                // as `get_matches`
                e.exit()
            }
        }
    }

Parse env::args_os, exiting on failure.

Like Command::get_matches but doesn’t consume the Command.

Panics

If contradictory arguments or settings exist.

Examples
let mut cmd = Command::new("myprog")
    // Args and options go here...
    ;
let matches = cmd.get_matches_mut();

Parse env::args_os, returning a clap::Result on failure.

NOTE: This method WILL NOT exit when --help or --version (or short versions) are used. It will return a clap::Error, where the kind is a ErrorKind::DisplayHelp or ErrorKind::DisplayVersion respectively. You must call Error::exit or perform a std::process::exit.

Panics

If contradictory arguments or settings exist.

Examples
let matches = Command::new("myprog")
    // Args and options go here...
    .try_get_matches()
    .unwrap_or_else(|e| e.exit());
Examples found in repository?
src/derive.rs (line 97)
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    fn try_parse() -> Result<Self, Error> {
        let mut matches = ok!(<Self as CommandFactory>::command().try_get_matches());
        <Self as FromArgMatches>::from_arg_matches_mut(&mut matches).map_err(format_error::<Self>)
    }

Parse the specified arguments, exiting on failure.

NOTE: The first argument will be parsed as the binary name unless Command::no_binary_name is used.

Panics

If contradictory arguments or settings exist.

Examples
let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];

let matches = Command::new("myprog")
    // Args and options go here...
    .get_matches_from(arg_vec);
Examples found in repository?
src/builder/command.rs (line 490)
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    pub fn get_matches(self) -> ArgMatches {
        self.get_matches_from(&mut env::args_os())
    }
More examples
Hide additional examples
src/derive.rs (line 107)
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    fn parse_from<I, T>(itr: I) -> Self
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches = <Self as CommandFactory>::command().get_matches_from(itr);
        let res = <Self as FromArgMatches>::from_arg_matches_mut(&mut matches)
            .map_err(format_error::<Self>);
        match res {
            Ok(s) => s,
            Err(e) => {
                // Since this is more of a development-time error, we aren't doing as fancy of a quit
                // as `get_matches_from`
                e.exit()
            }
        }
    }

    /// Parse from iterator, return Err on error.
    fn try_parse_from<I, T>(itr: I) -> Result<Self, Error>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches = ok!(<Self as CommandFactory>::command().try_get_matches_from(itr));
        <Self as FromArgMatches>::from_arg_matches_mut(&mut matches).map_err(format_error::<Self>)
    }

    /// Update from iterator, exit on error
    fn update_from<I, T>(&mut self, itr: I)
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches = <Self as CommandFactory>::command_for_update().get_matches_from(itr);
        let res = <Self as FromArgMatches>::update_from_arg_matches_mut(self, &mut matches)
            .map_err(format_error::<Self>);
        if let Err(e) = res {
            // Since this is more of a development-time error, we aren't doing as fancy of a quit
            // as `get_matches_from`
            e.exit()
        }
    }

Parse the specified arguments, returning a clap::Result on failure.

NOTE: This method WILL NOT exit when --help or --version (or short versions) are used. It will return a clap::Error, where the kind is a ErrorKind::DisplayHelp or ErrorKind::DisplayVersion respectively. You must call Error::exit or perform a std::process::exit yourself.

NOTE: The first argument will be parsed as the binary name unless Command::no_binary_name is used.

Panics

If contradictory arguments or settings exist.

Examples
let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];

let matches = Command::new("myprog")
    // Args and options go here...
    .try_get_matches_from(arg_vec)
    .unwrap_or_else(|e| e.exit());
Examples found in repository?
src/builder/command.rs (line 548)
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    pub fn try_get_matches(self) -> ClapResult<ArgMatches> {
        // Start the parsing
        self.try_get_matches_from(&mut env::args_os())
    }
More examples
Hide additional examples
src/derive.rs (line 126)
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    fn try_parse_from<I, T>(itr: I) -> Result<Self, Error>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches = ok!(<Self as CommandFactory>::command().try_get_matches_from(itr));
        <Self as FromArgMatches>::from_arg_matches_mut(&mut matches).map_err(format_error::<Self>)
    }

    /// Update from iterator, exit on error
    fn update_from<I, T>(&mut self, itr: I)
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches = <Self as CommandFactory>::command_for_update().get_matches_from(itr);
        let res = <Self as FromArgMatches>::update_from_arg_matches_mut(self, &mut matches)
            .map_err(format_error::<Self>);
        if let Err(e) = res {
            // Since this is more of a development-time error, we aren't doing as fancy of a quit
            // as `get_matches_from`
            e.exit()
        }
    }

    /// Update from iterator, return Err on error.
    fn try_update_from<I, T>(&mut self, itr: I) -> Result<(), Error>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        let mut matches =
            ok!(<Self as CommandFactory>::command_for_update().try_get_matches_from(itr));
        <Self as FromArgMatches>::update_from_arg_matches_mut(self, &mut matches)
            .map_err(format_error::<Self>)
    }

Parse the specified arguments, returning a clap::Result on failure.

Like Command::try_get_matches_from but doesn’t consume the Command.

NOTE: This method WILL NOT exit when --help or --version (or short versions) are used. It will return a clap::Error, where the kind is a ErrorKind::DisplayHelp or ErrorKind::DisplayVersion respectively. You must call Error::exit or perform a std::process::exit yourself.

NOTE: The first argument will be parsed as the binary name unless Command::no_binary_name is used.

Panics

If contradictory arguments or settings exist.

Examples
let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];

let mut cmd = Command::new("myprog");
    // Args and options go here...
let matches = cmd.try_get_matches_from_mut(arg_vec)
    .unwrap_or_else(|e| e.exit());
Examples found in repository?
src/builder/command.rs (line 513)
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    pub fn get_matches_mut(&mut self) -> ArgMatches {
        self.try_get_matches_from_mut(&mut env::args_os())
            .unwrap_or_else(|e| e.exit())
    }

    /// Parse [`env::args_os`], returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a
    /// [`ErrorKind::DisplayHelp`] or [`ErrorKind::DisplayVersion`] respectively. You must call
    /// [`Error::exit`] or perform a [`std::process::exit`].
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches()
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`env::args_os`]: std::env::args_os()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Result`]: Result
    /// [`clap::Error`]: crate::Error
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    #[inline]
    pub fn try_get_matches(self) -> ClapResult<ArgMatches> {
        // Start the parsing
        self.try_get_matches_from(&mut env::args_os())
    }

    /// Parse the specified arguments, exiting on failure.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .get_matches_from(arg_vec);
    /// ```
    /// [`Command::get_matches`]: Command::get_matches()
    /// [`clap::Result`]: Result
    /// [`Vec`]: std::vec::Vec
    pub fn get_matches_from<I, T>(mut self, itr: I) -> ArgMatches
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr).unwrap_or_else(|e| {
            drop(self);
            e.exit()
        })
    }

    /// Parse the specified arguments, returning a [`clap::Result`] on failure.
    ///
    /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
    /// used. It will return a [`clap::Error`], where the [`kind`] is a [`ErrorKind::DisplayHelp`]
    /// or [`ErrorKind::DisplayVersion`] respectively. You must call [`Error::exit`] or
    /// perform a [`std::process::exit`] yourself.
    ///
    /// **NOTE:** The first argument will be parsed as the binary name unless
    /// [`Command::no_binary_name`] is used.
    ///
    /// # Panics
    ///
    /// If contradictory arguments or settings exist.
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{Command, Arg};
    /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
    ///
    /// let matches = Command::new("myprog")
    ///     // Args and options go here...
    ///     .try_get_matches_from(arg_vec)
    ///     .unwrap_or_else(|e| e.exit());
    /// ```
    /// [`Command::get_matches_from`]: Command::get_matches_from()
    /// [`Command::try_get_matches`]: Command::try_get_matches()
    /// [`Error::exit`]: crate::Error::exit()
    /// [`std::process::exit`]: std::process::exit()
    /// [`clap::Error`]: crate::Error
    /// [`Error::exit`]: crate::Error::exit()
    /// [`kind`]: crate::Error
    /// [`ErrorKind::DisplayHelp`]: crate::error::ErrorKind::DisplayHelp
    /// [`ErrorKind::DisplayVersion`]: crate::error::ErrorKind::DisplayVersion
    /// [`clap::Result`]: Result
    pub fn try_get_matches_from<I, T>(mut self, itr: I) -> ClapResult<ArgMatches>
    where
        I: IntoIterator<Item = T>,
        T: Into<OsString> + Clone,
    {
        self.try_get_matches_from_mut(itr)
    }

Prints the short help message (-h) to io::stdout().

See also Command::print_long_help.

Examples
let mut cmd = Command::new("myprog");
cmd.print_help();

Prints the long help message (--help) to io::stdout().

See also Command::print_help.

Examples
let mut cmd = Command::new("myprog");
cmd.print_long_help();

Render the short help message (-h) to a StyledStr

See also Command::render_long_help.

Examples
use std::io;
let mut cmd = Command::new("myprog");
let mut out = io::stdout();
let help = cmd.render_help();
println!("{}", help);

Render the long help message (--help) to a StyledStr.

See also Command::render_help.

Examples
use std::io;
let mut cmd = Command::new("myprog");
let mut out = io::stdout();
let help = cmd.render_long_help();
println!("{}", help);

Version message rendered as if the user ran -V.

See also Command::render_long_version.

Coloring

This function does not try to color the message nor it inserts any ANSI escape codes.

Examples
use std::io;
let cmd = Command::new("myprog");
println!("{}", cmd.render_version());

Version message rendered as if the user ran --version.

See also Command::render_version.

Coloring

This function does not try to color the message nor it inserts any ANSI escape codes.

Examples
use std::io;
let cmd = Command::new("myprog");
println!("{}", cmd.render_long_version());

Usage statement

Examples
use std::io;
let mut cmd = Command::new("myprog");
println!("{}", cmd.render_usage());

Application-wide Settings

These settings will apply to the top-level command and all subcommands, by default. Some settings can be overridden in subcommands.

Specifies that the parser should not assume the first argument passed is the binary name.

This is normally the case when using a “daemon” style mode. For shells / REPLs, see Command::multicall.

Examples
let m = Command::new("myprog")
    .no_binary_name(true)
    .arg(arg!(<cmd> ... "commands to run"))
    .get_matches_from(vec!["command", "set"]);

let cmds: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
assert_eq!(cmds, ["command", "set"]);

Try not to fail on parse errors, like missing option values.

NOTE: This choice is propagated to all child subcommands.

Examples
let cmd = Command::new("cmd")
  .ignore_errors(true)
  .arg(arg!(-c --config <FILE> "Sets a custom config file"))
  .arg(arg!(-x --stuff <FILE> "Sets a custom stuff file"))
  .arg(arg!(f: -f "Flag"));

let r = cmd.try_get_matches_from(vec!["cmd", "-c", "file", "-f", "-x"]);

assert!(r.is_ok(), "unexpected error: {:?}", r);
let m = r.unwrap();
assert_eq!(m.get_one::<String>("config").unwrap(), "file");
assert!(*m.get_one::<bool>("f").expect("defaulted"));
assert_eq!(m.get_one::<String>("stuff"), None);

Replace prior occurrences of arguments rather than error

For any argument that would conflict with itself by default (e.g. ArgAction::Set, it will now override itself.

This is the equivalent to saying the foo arg using Arg::overrides_with("foo") for all defined arguments.

NOTE: This choice is propagated to all child subcommands.

Disables the automatic delimiting of values after -- or when Command::trailing_var_arg was used.

NOTE: The same thing can be done manually by setting the final positional argument to Arg::value_delimiter(None). Using this setting is safer, because it’s easier to locate when making changes.

NOTE: This choice is propagated to all child subcommands.

Examples
Command::new("myprog")
    .dont_delimit_trailing_values(true)
    .get_matches();
Available on crate feature color only.

Sets when to color output.

NOTE: This choice is propagated to all child subcommands.

NOTE: Default behaviour is ColorChoice::Auto.

Examples
Command::new("myprog")
    .color(ColorChoice::Never)
    .get_matches();
Available on non-crate feature unstable-v5 or crate feature wrap_help only.

Sets the terminal width at which to wrap help messages.

Using 0 will ignore terminal widths and use source formatting.

Defaults to current terminal width when wrap_help feature flag is enabled. If the flag is disabled or it cannot be determined, the default is 100.

NOTE: This setting applies globally and not on a per-command basis.

NOTE: This requires the wrap_help feature

Examples
Command::new("myprog")
    .term_width(80)
Available on non-crate feature unstable-v5 or crate feature wrap_help only.

Limit the line length for wrapping help when using the current terminal’s width.

This only applies when term_width is unset so that the current terminal’s width will be used. See Command::term_width for more details.

Using 0 will ignore terminal widths and use source formatting (default).

NOTE: This setting applies globally and not on a per-command basis.

NOTE: This requires the wrap_help feature

Examples
Command::new("myprog")
    .max_term_width(100)

Disables -V and --version flag.

Examples
let res = Command::new("myprog")
    .disable_version_flag(true)
    .try_get_matches_from(vec![
        "myprog", "-V"
    ]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);

Specifies to use the version of the current command for all subcommands.

Defaults to false; subcommands have independent version strings from their parents.

NOTE: This choice is propagated to all child subcommands.

Examples
Command::new("myprog")
    .version("v1.1")
    .propagate_version(true)
    .subcommand(Command::new("test"))
    .get_matches();
// running `$ myprog test --version` will display
// "myprog-test v1.1"

Places the help string for all arguments and subcommands on the line after them.

NOTE: This choice is propagated to all child subcommands.

Examples
Command::new("myprog")
    .next_line_help(true)
    .get_matches();

Disables -h and --help flag.

NOTE: This choice is propagated to all child subcommands.

Examples
let res = Command::new("myprog")
    .disable_help_flag(true)
    .try_get_matches_from(vec![
        "myprog", "-h"
    ]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);

Disables the help subcommand.

Examples
let res = Command::new("myprog")
    .disable_help_subcommand(true)
    // Normally, creating a subcommand causes a `help` subcommand to automatically
    // be generated as well
    .subcommand(Command::new("test"))
    .try_get_matches_from(vec![
        "myprog", "help"
    ]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::InvalidSubcommand);

Disables colorized help messages.

NOTE: This choice is propagated to all child subcommands.

Examples
Command::new("myprog")
    .disable_colored_help(true)
    .get_matches();

Panic if help descriptions are omitted.

NOTE: When deriving Parser, you could instead check this at compile-time with #![deny(missing_docs)]

NOTE: This choice is propagated to all child subcommands.

Examples
Command::new("myprog")
    .help_expected(true)
    .arg(
        Arg::new("foo").help("It does foo stuff")
        // As required via `help_expected`, a help message was supplied
     )
Panics
Command::new("myapp")
    .help_expected(true)
    .arg(
        Arg::new("foo")
        // Someone forgot to put .about("...") here
        // Since the setting `help_expected` is activated, this will lead to
        // a panic (if you are in debug mode)
    )

Tells clap not to print possible values when displaying help information.

This can be useful if there are many values, or they are explained elsewhere.

To set this per argument, see Arg::hide_possible_values.

NOTE: This choice is propagated to all child subcommands.

Allow partial matches of long arguments or their aliases.

For example, to match an argument named --test, one could use --t, --te, --tes, and --test.

NOTE: The match must not be ambiguous at all in order to succeed. i.e. to match --te to --test there could not also be another argument or alias --temp because both start with --te

NOTE: This choice is propagated to all child subcommands.

Allow partial matches of subcommand names and their aliases.

For example, to match a subcommand named test, one could use t, te, tes, and test.

NOTE: The match must not be ambiguous at all in order to succeed. i.e. to match te to test there could not also be a subcommand or alias temp because both start with te

CAUTION: This setting can interfere with positional/free arguments, take care when designing CLIs which allow inferred subcommands and have potential positional/free arguments whose values could start with the same characters as subcommands. If this is the case, it’s recommended to use settings such as Command::args_conflicts_with_subcommands in conjunction with this setting.

NOTE: This choice is propagated to all child subcommands.

Examples
let m = Command::new("prog")
    .infer_subcommands(true)
    .subcommand(Command::new("test"))
    .get_matches_from(vec![
        "prog", "te"
    ]);
assert_eq!(m.subcommand_name(), Some("test"));

Command-specific Settings

These apply only to the current command and are not inherited by subcommands.

(Re)Sets the program’s name.

See Command::new for more details.

Examples
let cmd = clap::command!()
    .name("foo");

// continued logic goes here, such as `cmd.get_matches()` etc.

Overrides the runtime-determined name of the binary for help and error messages.

This should only be used when absolutely necessary, such as when the binary name for your application is misleading, or perhaps not how the user should invoke your program.

Pro-tip: When building things such as third party cargo subcommands, this setting should be used!

NOTE: This does not change or set the name of the binary file on disk. It only changes what clap thinks the name is for the purposes of error or help messages.

Examples
Command::new("My Program")
     .bin_name("my_binary")

Overrides the runtime-determined display name of the program for help and error messages.

Examples
Command::new("My Program")
     .display_name("my_program")

Sets the author(s) for the help message.

Pro-tip: Use claps convenience macro crate_authors! to automatically set your application’s author(s) to the same thing as your crate at compile time.

NOTE: A custom help_template is needed for author to show up.

Examples
Command::new("myprog")
     .author("Me, me@mymain.com")

Sets the program’s description for the short help (-h).

If Command::long_about is not specified, this message will be displayed for --help.

NOTE: Only Command::about (short format) is used in completion script generation in order to be concise.

See also crate_description!.

Examples
Command::new("myprog")
    .about("Does really amazing things for great people")
Examples found in repository?
src/builder/command.rs (line 4274)
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    pub(crate) fn _check_help_and_version(&mut self, expand_help_tree: bool) {
        debug!(
            "Command::_check_help_and_version:{} expand_help_tree={}",
            self.name, expand_help_tree
        );

        self.long_help_exists = self.long_help_exists_();

        if !self.is_disable_help_flag_set() {
            debug!("Command::_check_help_and_version: Building default --help");
            let mut arg = Arg::new(Id::HELP)
                .short('h')
                .long("help")
                .action(ArgAction::Help);
            if self.long_help_exists {
                arg = arg
                    .help("Print help information (use `--help` for more detail)")
                    .long_help("Print help information (use `-h` for a summary)");
            } else {
                arg = arg.help("Print help information");
            }
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }
        if !self.is_disable_version_flag_set() {
            debug!("Command::_check_help_and_version: Building default --version");
            let arg = Arg::new(Id::VERSION)
                .short('V')
                .long("version")
                .action(ArgAction::Version)
                .help("Print version information");
            // Avoiding `arg_internal` to not be sensitive to `next_help_heading` /
            // `next_display_order`
            self.args.push(arg);
        }

        if !self.is_set(AppSettings::DisableHelpSubcommand) {
            debug!("Command::_check_help_and_version: Building help subcommand");
            let help_about = "Print this message or the help of the given subcommand(s)";

            let mut help_subcmd = if expand_help_tree {
                // Slow code path to recursively clone all other subcommand subtrees under help
                let help_subcmd = Command::new("help")
                    .about(help_about)
                    .global_setting(AppSettings::DisableHelpSubcommand)
                    .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));

                let mut help_help_subcmd = Command::new("help").about(help_about);
                help_help_subcmd.version = None;
                help_help_subcmd.long_version = None;
                help_help_subcmd = help_help_subcmd
                    .setting(AppSettings::DisableHelpFlag)
                    .setting(AppSettings::DisableVersionFlag);

                help_subcmd.subcommand(help_help_subcmd)
            } else {
                Command::new("help").about(help_about).arg(
                    Arg::new("subcommand")
                        .action(ArgAction::Append)
                        .num_args(..)
                        .value_name("COMMAND")
                        .help("Print help for the subcommand(s)"),
                )
            };
            self._propagate_subcommand(&mut help_subcmd);

            // The parser acts like this is set, so let's set it so we don't falsely
            // advertise it to the user
            help_subcmd.version = None;
            help_subcmd.long_version = None;
            help_subcmd = help_subcmd
                .setting(AppSettings::DisableHelpFlag)
                .setting(AppSettings::DisableVersionFlag)
                .unset_global_setting(AppSettings::PropagateVersion);

            self.subcommands.push(help_subcmd);
        }
    }

    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

Sets the program’s description for the long help (--help).

If Command::about is not specified, this message will be displayed for -h.

NOTE: Only Command::about (short format) is used in completion script generation in order to be concise.

Examples
Command::new("myprog")
    .long_about(
"Does really amazing things to great people. Now let's talk a little
 more in depth about how this subcommand really works. It may take about
 a few lines of text, but that's ok!")

Free-form help text for after auto-generated short help (-h).

This is often used to describe how to use the arguments, caveats to be noted, or license and contact information.

If Command::after_long_help is not specified, this message will be displayed for --help.

Examples
Command::new("myprog")
    .after_help("Does really amazing things for great people... but be careful with -R!")

Free-form help text for after auto-generated long help (--help).

This is often used to describe how to use the arguments, caveats to be noted, or license and contact information.

If Command::after_help is not specified, this message will be displayed for -h.

Examples
Command::new("myprog")
    .after_long_help("Does really amazing things to great people... but be careful with -R, \
                     like, for real, be careful with this!")

Free-form help text for before auto-generated short help (-h).

This is often used for header, copyright, or license information.

If Command::before_long_help is not specified, this message will be displayed for --help.

Examples
Command::new("myprog")
    .before_help("Some info I'd like to appear before the help info")

Free-form help text for before auto-generated long help (--help).

This is often used for header, copyright, or license information.

If Command::before_help is not specified, this message will be displayed for -h.

Examples
Command::new("myprog")
    .before_long_help("Some verbose and long info I'd like to appear before the help info")

Sets the version for the short version (-V) and help messages.

If Command::long_version is not specified, this message will be displayed for --version.

Pro-tip: Use claps convenience macro crate_version! to automatically set your application’s version to the same thing as your crate at compile time.

Examples
Command::new("myprog")
    .version("v0.1.24")

Sets the version for the long version (--version) and help messages.

If Command::version is not specified, this message will be displayed for -V.

Pro-tip: Use claps convenience macro crate_version! to automatically set your application’s version to the same thing as your crate at compile time.

Examples
Command::new("myprog")
    .long_version(
"v0.1.24
 commit: abcdef89726d
 revision: 123
 release: 2
 binary: myprog")

Overrides the clap generated usage string for help and error messages.

NOTE: Using this setting disables claps “context-aware” usage strings. After this setting is set, this will be the only usage string displayed to the user!

NOTE: Multiple usage lines may be present in the usage argument, but some rules need to be followed to ensure the usage lines are formatted correctly by the default help formatter:

  • Do not indent the first usage line.
  • Indent all subsequent usage lines with seven spaces.
  • The last line must not end with a newline.
Examples
Command::new("myprog")
    .override_usage("myapp [-clDas] <some_file>")

Or for multiple usage lines:

Command::new("myprog")
    .override_usage(
        "myapp -X [-a] [-b] <file>\n       \
         myapp -Y [-c] <file1> <file2>\n       \
         myapp -Z [-d|-e]"
    )

Overrides the clap generated help message (both -h and --help).

This should only be used when the auto-generated message does not suffice.

NOTE: This only replaces the help message for the current command, meaning if you are using subcommands, those help messages will still be auto-generated unless you specify a Command::override_help for them as well.

Examples
Command::new("myapp")
    .override_help("myapp v1.0\n\
           Does awesome things\n\
           (C) me@mail.com\n\n\

           Usage: myapp <opts> <command>\n\n\

           Options:\n\
           -h, --help       Display this message\n\
           -V, --version    Display version info\n\
           -s <stuff>       Do something with stuff\n\
           -v               Be verbose\n\n\

           Commands:\n\
           help             Print this message\n\
           work             Do some work")
Available on crate feature help only.

Sets the help template to be used, overriding the default format.

NOTE: The template system is by design very simple. Therefore, the tags have to be written in the lowercase and without spacing.

Tags are given inside curly brackets.

Valid tags are:

  • {name} - Display name for the (sub-)command.
  • {bin} - Binary name.
  • {version} - Version number.
  • {author} - Author information.
  • {author-with-newline} - Author followed by \n.
  • {author-section} - Author preceded and followed by \n.
  • {about} - General description (from Command::about or Command::long_about).
  • {about-with-newline} - About followed by \n.
  • {about-section} - About preceded and followed by ‘\n’.
  • {usage-heading} - Automatically generated usage heading.
  • {usage} - Automatically generated or given usage string.
  • {all-args} - Help for all arguments (options, flags, positional arguments, and subcommands) including titles.
  • {options} - Help for options.
  • {positionals} - Help for positional arguments.
  • {subcommands} - Help for subcommands.
  • {tag} - Standard tab sized used within clap
  • {after-help} - Help from Command::after_help or Command::after_long_help.
  • {before-help} - Help from Command::before_help or Command::before_long_help.
Examples

For a very brief help:

Command::new("myprog")
    .version("1.0")
    .help_template("{bin} ({version}) - {usage}")

For showing more application context:

Command::new("myprog")
    .version("1.0")
    .help_template("\
{before-help}{name} {version}
{author-with-newline}{about-with-newline}
{usage-heading} {usage}

{all-args}{after-help}
")

Set the default section heading for future args.

This will be used for any arg that hasn’t had Arg::help_heading called.

This is useful if the default Options or Arguments headings are not specific enough for one’s use case.

For subcommands, see Command::subcommand_help_heading

Change the starting value for assigning future display orders for ags.

This will be used for any arg that hasn’t had Arg::display_order called.

Available on crate feature unstable-replace only.

Replaces an argument or subcommand used on the CLI at runtime with other arguments or subcommands.

Note: This is gated behind unstable-replace

When this method is used, name is removed from the CLI, and target is inserted in its place. Parsing continues as if the user typed target instead of name.

This can be used to create “shortcuts” for subcommands, or if a particular argument has the semantic meaning of several other specific arguments and values.

Examples

We’ll start with the “subcommand short” example. In this example, let’s assume we have a program with a subcommand module which can be invoked via cmd module. Now let’s also assume module also has a subcommand called install which can be invoked cmd module install. If for some reason users needed to be able to reach cmd module install via the short-hand cmd install, we’d have several options.

We could create another sibling subcommand to module called install, but then we would need to manage another subcommand and manually dispatch to cmd module install handling code. This is error prone and tedious.

We could instead use Command::replace so that, when the user types cmd install, clap will replace install with module install which will end up getting parsed as if the user typed the entire incantation.

let m = Command::new("cmd")
    .subcommand(Command::new("module")
        .subcommand(Command::new("install")))
    .replace("install", &["module", "install"])
    .get_matches_from(vec!["cmd", "install"]);

assert!(m.subcommand_matches("module").is_some());
assert!(m.subcommand_matches("module").unwrap().subcommand_matches("install").is_some());

Now let’s show an argument example!

Let’s assume we have an application with two flags --save-context and --save-runtime. But often users end up needing to do both at the same time. We can add a third flag --save-all which semantically means the same thing as cmd --save-context --save-runtime. To implement that, we have several options.

We could create this third argument and manually check if that argument and in our own consumer code handle the fact that both --save-context and --save-runtime should have been used. But again this is error prone and tedious. If we had code relying on checking --save-context and we forgot to update that code to also check --save-all it’d mean an error!

Luckily we can use Command::replace so that when the user types --save-all, clap will replace that argument with --save-context --save-runtime, and parsing will continue like normal. Now all our code that was originally checking for things like --save-context doesn’t need to change!

let m = Command::new("cmd")
    .arg(Arg::new("save-context")
        .long("save-context")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("save-runtime")
        .long("save-runtime")
        .action(ArgAction::SetTrue))
    .replace("--save-all", &["--save-context", "--save-runtime"])
    .get_matches_from(vec!["cmd", "--save-all"]);

assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));

This can also be used with options, for example if our application with --save-* above also had a --format=TYPE option. Let’s say it accepted txt or json values. However, when --save-all is used, only --format=json is allowed, or valid. We could change the example above to enforce this:

let m = Command::new("cmd")
    .arg(Arg::new("save-context")
        .long("save-context")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("save-runtime")
        .long("save-runtime")
        .action(ArgAction::SetTrue))
    .arg(Arg::new("format")
        .long("format")
        .action(ArgAction::Set)
        .value_parser(["txt", "json"]))
    .replace("--save-all", &["--save-context", "--save-runtime", "--format=json"])
    .get_matches_from(vec!["cmd", "--save-all"]);

assert!(*m.get_one::<bool>("save-context").expect("defaulted by clap"));
assert!(*m.get_one::<bool>("save-runtime").expect("defaulted by clap"));
assert_eq!(m.get_one::<String>("format").unwrap(), "json");

Exit gracefully if no arguments are present (e.g. $ myprog).

NOTE: subcommands count as arguments

Examples
Command::new("myprog")
    .arg_required_else_help(true);

Allows one to implement two styles of CLIs where positionals can be used out of order.

The first example is a CLI where the second to last positional argument is optional, but the final positional argument is required. Such as $ prog [optional] <required> where one of the two following usages is allowed:

  • $ prog [optional] <required>
  • $ prog <required>

This would otherwise not be allowed. This is useful when [optional] has a default value.

Note: when using this style of “missing positionals” the final positional must be required if -- will not be used to skip to the final positional argument.

Note: This style also only allows a single positional argument to be “skipped” without the use of --. To skip more than one, see the second example.

The second example is when one wants to skip multiple optional positional arguments, and use of the -- operator is OK (but not required if all arguments will be specified anyways).

For example, imagine a CLI which has three positional arguments [foo] [bar] [baz]... where baz accepts multiple values (similar to man ARGS... style training arguments).

With this setting the following invocations are posisble:

  • $ prog foo bar baz1 baz2 baz3
  • $ prog foo -- baz1 baz2 baz3
  • $ prog -- baz1 baz2 baz3
Examples

Style number one from above:

// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .allow_missing_positional(true)
    .arg(Arg::new("arg1"))
    .arg(Arg::new("arg2")
        .required(true))
    .get_matches_from(vec![
        "prog", "other"
    ]);

assert_eq!(m.get_one::<String>("arg1"), None);
assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");

Now the same example, but using a default value for the first optional positional argument

// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .allow_missing_positional(true)
    .arg(Arg::new("arg1")
        .default_value("something"))
    .arg(Arg::new("arg2")
        .required(true))
    .get_matches_from(vec![
        "prog", "other"
    ]);

assert_eq!(m.get_one::<String>("arg1").unwrap(), "something");
assert_eq!(m.get_one::<String>("arg2").unwrap(), "other");

Style number two from above:

// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .allow_missing_positional(true)
    .arg(Arg::new("foo"))
    .arg(Arg::new("bar"))
    .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    .get_matches_from(vec![
        "prog", "foo", "bar", "baz1", "baz2", "baz3"
    ]);

assert_eq!(m.get_one::<String>("foo").unwrap(), "foo");
assert_eq!(m.get_one::<String>("bar").unwrap(), "bar");
assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);

Now nofice if we don’t specify foo or baz but use the -- operator.

// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .allow_missing_positional(true)
    .arg(Arg::new("foo"))
    .arg(Arg::new("bar"))
    .arg(Arg::new("baz").action(ArgAction::Set).num_args(1..))
    .get_matches_from(vec![
        "prog", "--", "baz1", "baz2", "baz3"
    ]);

assert_eq!(m.get_one::<String>("foo"), None);
assert_eq!(m.get_one::<String>("bar"), None);
assert_eq!(m.get_many::<String>("baz").unwrap().collect::<Vec<_>>(), &["baz1", "baz2", "baz3"]);

Sets the short version of the subcommand flag without the preceding -.

Allows the subcommand to be used as if it were an Arg::short.

Examples
let matches = Command::new("pacman")
    .subcommand(
        Command::new("sync").short_flag('S').arg(
            Arg::new("search")
                .short('s')
                .long("search")
                .action(ArgAction::SetTrue)
                .help("search remote repositories for matching strings"),
        ),
    )
    .get_matches_from(vec!["pacman", "-Ss"]);

assert_eq!(matches.subcommand_name().unwrap(), "sync");
let sync_matches = matches.subcommand_matches("sync").unwrap();
assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));

Sets the long version of the subcommand flag without the preceding --.

Allows the subcommand to be used as if it were an Arg::long.

NOTE: Any leading - characters will be stripped.

Examples

To set long_flag use a word containing valid UTF-8 codepoints. If you supply a double leading -- such as --sync they will be stripped. Hyphens in the middle of the word; however, will not be stripped (i.e. sync-file is allowed).

let matches = Command::new("pacman")
    .subcommand(
        Command::new("sync").long_flag("sync").arg(
            Arg::new("search")
                .short('s')
                .long("search")
                .action(ArgAction::SetTrue)
                .help("search remote repositories for matching strings"),
        ),
    )
    .get_matches_from(vec!["pacman", "--sync", "--search"]);

assert_eq!(matches.subcommand_name().unwrap(), "sync");
let sync_matches = matches.subcommand_matches("sync").unwrap();
assert!(*sync_matches.get_one::<bool>("search").expect("defaulted by clap"));

Sets a hidden alias to this subcommand.

This allows the subcommand to be accessed via either the original name, or this given alias. This is more efficient and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all aliased variants.

NOTE: Aliases defined with this method are hidden from the help message. If you’re looking for aliases that will be displayed in the help message, see Command::visible_alias.

NOTE: When using aliases and checking for the existence of a particular subcommand within an ArgMatches struct, one only needs to search for the original name and not all aliases.

Examples
let m = Command::new("myprog")
    .subcommand(Command::new("test")
        .alias("do-stuff"))
    .get_matches_from(vec!["myprog", "do-stuff"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add an alias, which functions as “hidden” short flag subcommand

This will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").short_flag('t')
                .short_flag_alias('d'))
            .get_matches_from(vec!["myprog", "-d"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add an alias, which functions as a “hidden” long flag subcommand.

This will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").long_flag("test")
                .long_flag_alias("testing"))
            .get_matches_from(vec!["myprog", "--testing"]);
assert_eq!(m.subcommand_name(), Some("test"));
Examples found in repository?
src/builder/command.rs (line 2414)
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    pub fn long_flag_aliases(mut self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self {
        for s in names {
            self = self.long_flag_alias(s)
        }
        self
    }

Sets multiple hidden aliases to this subcommand.

This allows the subcommand to be accessed via either the original name or any of the given aliases. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command and not all aliased variants.

NOTE: Aliases defined with this method are hidden from the help message. If looking for aliases that will be displayed in the help message, see Command::visible_aliases.

NOTE: When using aliases and checking for the existence of a particular subcommand within an ArgMatches struct, one only needs to search for the original name and not all aliases.

Examples
let m = Command::new("myprog")
    .subcommand(Command::new("test")
        .aliases(["do-stuff", "do-tests", "tests"]))
        .arg(Arg::new("input")
            .help("the file to add")
            .required(false))
    .get_matches_from(vec!["myprog", "do-tests"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add aliases, which function as “hidden” short flag subcommands.

These will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples
let m = Command::new("myprog")
    .subcommand(Command::new("test").short_flag('t')
        .short_flag_aliases(['a', 'b', 'c']))
        .arg(Arg::new("input")
            .help("the file to add")
            .required(false))
    .get_matches_from(vec!["myprog", "-a"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add aliases, which function as “hidden” long flag subcommands.

These will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").long_flag("test")
                .long_flag_aliases(["testing", "testall", "test_all"]))
                .arg(Arg::new("input")
                            .help("the file to add")
                            .required(false))
            .get_matches_from(vec!["myprog", "--testing"]);
assert_eq!(m.subcommand_name(), Some("test"));

Sets a visible alias to this subcommand.

This allows the subcommand to be accessed via either the original name or the given alias. This is more efficient and easier than creating hidden subcommands as one only needs to check for the existence of this command and not all aliased variants.

NOTE: The alias defined with this method is visible from the help message and displayed as if it were just another regular subcommand. If looking for an alias that will not be displayed in the help message, see Command::alias.

NOTE: When using aliases and checking for the existence of a particular subcommand within an ArgMatches struct, one only needs to search for the original name and not all aliases.

Examples
let m = Command::new("myprog")
    .subcommand(Command::new("test")
        .visible_alias("do-stuff"))
    .get_matches_from(vec!["myprog", "do-stuff"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add an alias, which functions as “visible” short flag subcommand

This will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

See also Command::short_flag_alias.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").short_flag('t')
                .visible_short_flag_alias('d'))
            .get_matches_from(vec!["myprog", "-d"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add an alias, which functions as a “visible” long flag subcommand.

This will automatically dispatch as if this subcommand was used. This is more efficient, and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command, and not all variants.

See also Command::long_flag_alias.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").long_flag("test")
                .visible_long_flag_alias("testing"))
            .get_matches_from(vec!["myprog", "--testing"]);
assert_eq!(m.subcommand_name(), Some("test"));
Examples found in repository?
src/builder/command.rs (line 2594)
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    pub fn visible_long_flag_aliases(
        mut self,
        names: impl IntoIterator<Item = impl Into<Str>>,
    ) -> Self {
        for s in names {
            self = self.visible_long_flag_alias(s);
        }
        self
    }

Sets multiple visible aliases to this subcommand.

This allows the subcommand to be accessed via either the original name or any of the given aliases. This is more efficient and easier than creating multiple hidden subcommands as one only needs to check for the existence of this command and not all aliased variants.

NOTE: The alias defined with this method is visible from the help message and displayed as if it were just another regular subcommand. If looking for an alias that will not be displayed in the help message, see Command::alias.

NOTE: When using aliases, and checking for the existence of a particular subcommand within an ArgMatches struct, one only needs to search for the original name and not all aliases.

Examples
let m = Command::new("myprog")
    .subcommand(Command::new("test")
        .visible_aliases(["do-stuff", "tests"]))
    .get_matches_from(vec!["myprog", "do-stuff"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add aliases, which function as visible short flag subcommands.

See Command::short_flag_aliases.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").short_flag('b')
                .visible_short_flag_aliases(['t']))
            .get_matches_from(vec!["myprog", "-t"]);
assert_eq!(m.subcommand_name(), Some("test"));

Add aliases, which function as visible long flag subcommands.

See Command::long_flag_aliases.

Examples
let m = Command::new("myprog")
            .subcommand(Command::new("test").long_flag("test")
                .visible_long_flag_aliases(["testing", "testall", "test_all"]))
            .get_matches_from(vec!["myprog", "--testing"]);
assert_eq!(m.subcommand_name(), Some("test"));

Set the placement of this subcommand within the help.

Subcommands with a lower value will be displayed first in the help message. Subcommands with duplicate display orders will be displayed in alphabetical order.

This is helpful when one would like to emphasize frequently used subcommands, or prioritize those towards the top of the list.

NOTE: The default is 999 for all subcommands.

Examples
let m = Command::new("cust-ord")
   .subcommand(Command::new("alpha") // typically subcommands are grouped
                                              // alphabetically by name. Subcommands
                                              // without a display_order have a value of
                                              // 999 and are displayed alphabetically with
                                              // all other 999 subcommands
       .about("Some help and text"))
   .subcommand(Command::new("beta")
       .display_order(1)   // In order to force this subcommand to appear *first*
                           // all we have to do is give it a value lower than 999.
                           // Any other subcommands with a value of 1 will be displayed
                           // alphabetically with this one...then 2 values, then 3, etc.
       .about("I should be first!"))
   .get_matches_from(vec![
       "cust-ord", "--help"
   ]);

The above example displays the following help message

cust-ord

Usage: cust-ord [OPTIONS]

Commands:
    beta    I should be first!
    alpha   Some help and text

Options:
    -h, --help       Print help information
    -V, --version    Print version information

Specifies that this subcommand should be hidden from help messages

Examples
Command::new("myprog")
    .subcommand(
        Command::new("test").hide(true)
    )
Examples found in repository?
src/builder/command.rs (line 4312)
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    fn _copy_subtree_for_help(&self) -> Command {
        let mut cmd = Command::new(self.name.clone())
            .hide(self.is_hide_set())
            .global_setting(AppSettings::DisableHelpFlag)
            .global_setting(AppSettings::DisableVersionFlag)
            .subcommands(self.get_subcommands().map(Command::_copy_subtree_for_help));
        if self.get_about().is_some() {
            cmd = cmd.about(self.get_about().unwrap().clone());
        }
        cmd
    }

If no subcommand is present at runtime, error and exit gracefully.

Examples
let err = Command::new("myprog")
    .subcommand_required(true)
    .subcommand(Command::new("test"))
    .try_get_matches_from(vec![
        "myprog",
    ]);
assert!(err.is_err());
assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingSubcommand);

Assume unexpected positional arguments are a subcommand.

Arguments will be stored in the "" argument in the ArgMatches

NOTE: Use this setting with caution, as a truly unexpected argument (i.e. one that is NOT an external subcommand) will not cause an error and instead be treated as a potential subcommand. One should check for such cases manually and inform the user appropriately.

NOTE: A built-in subcommand will be parsed as an external subcommand when escaped with --.

Examples
// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .allow_external_subcommands(true)
    .get_matches_from(vec![
        "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ]);

// All trailing arguments will be stored under the subcommand's sub-matches using an empty
// string argument name
match m.subcommand() {
    Some((external, ext_m)) => {
         let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
         assert_eq!(external, "subcmd");
         assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    },
    _ => {},
}

Specifies how to parse external subcommand arguments.

The default parser is for OsString. This can be used to switch it to String or another type.

NOTE: Setting this requires Command::allow_external_subcommands

Examples
// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
   .allow_external_subcommands(true)
   .get_matches_from(vec![
       "myprog", "subcmd", "--option", "value", "-fff", "--flag"
   ]);

// All trailing arguments will be stored under the subcommand's sub-matches using an empty
// string argument name
match m.subcommand() {
   Some((external, ext_m)) => {
        let ext_args: Vec<_> = ext_m.get_many::<OsString>("").unwrap().collect();
        assert_eq!(external, "subcmd");
        assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
   },
   _ => {},
}
// Assume there is an external subcommand named "subcmd"
let m = Command::new("myprog")
    .external_subcommand_value_parser(value_parser!(String))
    .get_matches_from(vec![
        "myprog", "subcmd", "--option", "value", "-fff", "--flag"
    ]);

// All trailing arguments will be stored under the subcommand's sub-matches using an empty
// string argument name
match m.subcommand() {
    Some((external, ext_m)) => {
         let ext_args: Vec<_> = ext_m.get_many::<String>("").unwrap().collect();
         assert_eq!(external, "subcmd");
         assert_eq!(ext_args, ["--option", "value", "-fff", "--flag"]);
    },
    _ => {},
}

Specifies that use of an argument prevents the use of subcommands.

By default clap allows arguments between subcommands such as <cmd> [cmd_args] <subcmd> [subcmd_args] <subsubcmd> [subsubcmd_args].

This setting disables that functionality and says that arguments can only follow the final subcommand. For instance using this setting makes only the following invocations possible:

  • <cmd> <subcmd> <subsubcmd> [subsubcmd_args]
  • <cmd> <subcmd> [subcmd_args]
  • <cmd> [cmd_args]
Examples
Command::new("myprog")
    .args_conflicts_with_subcommands(true);

Prevent subcommands from being consumed as an arguments value.

By default, if an option taking multiple values is followed by a subcommand, the subcommand will be parsed as another value.

cmd --foo val1 val2 subcommand
          --------- ----------
            values   another value

This setting instructs the parser to stop when encountering a subcommand instead of greedily consuming arguments.

cmd --foo val1 val2 subcommand
          --------- ----------
            values   subcommand
Examples
let cmd = Command::new("cmd").subcommand(Command::new("sub")).arg(
    Arg::new("arg")
        .long("arg")
        .num_args(1..)
        .action(ArgAction::Set),
);

let matches = cmd
    .clone()
    .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    .unwrap();
assert_eq!(
    matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    &["1", "2", "3", "sub"]
);
assert!(matches.subcommand_matches("sub").is_none());

let matches = cmd
    .subcommand_precedence_over_arg(true)
    .try_get_matches_from(&["cmd", "--arg", "1", "2", "3", "sub"])
    .unwrap();
assert_eq!(
    matches.get_many::<String>("arg").unwrap().collect::<Vec<_>>(),
    &["1", "2", "3"]
);
assert!(matches.subcommand_matches("sub").is_some());

Allows subcommands to override all requirements of the parent command.

For example, if you had a subcommand or top level application with a required argument that is only required as long as there is no subcommand present, using this setting would allow you to set those arguments to Arg::required(true) and yet receive no error so long as the user uses a valid subcommand instead.

NOTE: This defaults to false (using subcommand does not negate requirements)

Examples

This first example shows that it is an error to not use a required argument

let err = Command::new("myprog")
    .subcommand_negates_reqs(true)
    .arg(Arg::new("opt").required(true))
    .subcommand(Command::new("test"))
    .try_get_matches_from(vec![
        "myprog"
    ]);
assert!(err.is_err());
assert_eq!(err.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);

This next example shows that it is no longer error to not use a required argument if a valid subcommand is used.

let noerr = Command::new("myprog")
    .subcommand_negates_reqs(true)
    .arg(Arg::new("opt").required(true))
    .subcommand(Command::new("test"))
    .try_get_matches_from(vec![
        "myprog", "test"
    ]);
assert!(noerr.is_ok());

Multiple-personality program dispatched on the binary name (argv[0])

A “multicall” executable is a single executable that contains a variety of applets, and decides which applet to run based on the name of the file. The executable can be called from different names by creating hard links or symbolic links to it.

This is desirable for:

  • Easy distribution, a single binary that can install hardlinks to access the different personalities.
  • Minimal binary size by sharing common code (e.g. standard library, clap)
  • Custom shells or REPLs where there isn’t a single top-level command

Setting multicall will cause

  • argv[0] to be stripped to the base name and parsed as the first argument, as if