pub struct Arg { /* private fields */ }Expand description
The abstract representation of a command line argument. Used to set all the options and relationships that define a valid argument for the program.
There are two methods for constructing Args, using the builder pattern and setting options
manually, or using a usage string which is far less verbose but has fewer options. You can also
use a combination of the two methods to achieve the best of both worlds.
Examples
// Using the traditional builder pattern and setting each option manually
let cfg = Arg::new("config")
.short('c')
.long("config")
.action(ArgAction::Set)
.value_name("FILE")
.help("Provides a config file to myprog");
// Using a usage string (setting a similar argument to the one above)
let input = arg!(-i --input <FILE> "Provides an input file to the program");Implementations§
source§impl Arg
impl Arg
sourcepub fn new(id: impl Into<Id>) -> Self
pub fn new(id: impl Into<Id>) -> Self
Create a new Arg with a unique name.
The name is used to check whether or not the argument was used at runtime, get values, set relationships with other args, etc..
NOTE: In the case of arguments that take values (i.e. Arg::action(ArgAction::Set))
and positional arguments (i.e. those without a preceding - or --) the name will also
be displayed when the user prints the usage/help information of the program.
Examples
Arg::new("config")Examples found in repository?
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fn augment_args(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}
fn augment_args_for_update(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}More examples
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fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn id(self, id: impl Into<Id>) -> Self
pub fn id(self, id: impl Into<Id>) -> Self
Set the identifier used for referencing this argument in the clap API.
See Arg::new for more details.
sourcepub fn short(self, s: impl IntoResettable<char>) -> Self
pub fn short(self, s: impl IntoResettable<char>) -> Self
Sets the short version of the argument without the preceding -.
By default V and h are used by the auto-generated version and help arguments,
respectively. You will need to disable the auto-generated flags
(disable_help_flag,
disable_version_flag) and define your own.
Examples
When calling short, use a single valid UTF-8 character which will allow using the
argument via a single hyphen (-) such as -c:
let m = Command::new("prog")
.arg(Arg::new("config")
.short('c')
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "-c", "file.toml"
]);
assert_eq!(m.get_one::<String>("config").map(String::as_str), Some("file.toml"));To use -h for your own flag and still have help:
let m = Command::new("prog")
.disable_help_flag(true)
.arg(Arg::new("host")
.short('h')
.long("host"))
.arg(Arg::new("help")
.long("help")
.global(true)
.action(ArgAction::Help))
.get_matches_from(vec![
"prog", "-h", "wikipedia.org"
]);
assert_eq!(m.get_one::<String>("host").map(String::as_str), Some("wikipedia.org"));Examples found in repository?
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fn augment_args(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}
fn augment_args_for_update(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}More examples
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fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn long(self, l: impl IntoResettable<Str>) -> Self
pub fn long(self, l: impl IntoResettable<Str>) -> Self
Sets the long version of the argument without the preceding --.
By default version and help are used by the auto-generated version and help
arguments, respectively. You may use the word version or help for the long form of your
own arguments, in which case clap simply will not assign those to the auto-generated
version or help arguments.
NOTE: Any leading - characters will be stripped
Examples
To set long use a word containing valid UTF-8. If you supply a double leading
-- such as --config they will be stripped. Hyphens in the middle of the word, however,
will not be stripped (i.e. config-file is allowed).
Setting long allows using the argument via a double hyphen (--) such as --config
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "--config", "file.toml"
]);
assert_eq!(m.get_one::<String>("cfg").map(String::as_str), Some("file.toml"));Examples found in repository?
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
fn augment_args(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}
fn augment_args_for_update(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}More examples
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn alias(self, name: impl IntoResettable<Str>) -> Self
pub fn alias(self, name: impl IntoResettable<Str>) -> Self
Add an alias, which functions as a hidden long flag.
This is more efficient, and easier than creating multiple hidden arguments as one only needs to check for the existence of this command, and not all variants.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.long("test")
.alias("alias")
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "--alias", "cool"
]);
assert_eq!(m.get_one::<String>("test").unwrap(), "cool");sourcepub fn short_alias(self, name: impl IntoResettable<char>) -> Self
pub fn short_alias(self, name: impl IntoResettable<char>) -> Self
Add an alias, which functions as a hidden short flag.
This is more efficient, and easier than creating multiple hidden arguments as one only needs to check for the existence of this command, and not all variants.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.short('t')
.short_alias('e')
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "-e", "cool"
]);
assert_eq!(m.get_one::<String>("test").unwrap(), "cool");sourcepub fn aliases(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self
pub fn aliases(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self
Add aliases, which function as hidden long flags.
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("prog")
.arg(Arg::new("test")
.long("test")
.aliases(["do-stuff", "do-tests", "tests"])
.action(ArgAction::SetTrue)
.help("the file to add")
.required(false))
.get_matches_from(vec![
"prog", "--do-tests"
]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);sourcepub fn short_aliases(self, names: impl IntoIterator<Item = char>) -> Self
pub fn short_aliases(self, names: impl IntoIterator<Item = char>) -> Self
Add aliases, which functions as a hidden short flag.
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("prog")
.arg(Arg::new("test")
.short('t')
.short_aliases(['e', 's'])
.action(ArgAction::SetTrue)
.help("the file to add")
.required(false))
.get_matches_from(vec![
"prog", "-s"
]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);sourcepub fn visible_alias(self, name: impl IntoResettable<Str>) -> Self
pub fn visible_alias(self, name: impl IntoResettable<Str>) -> Self
Add an alias, which functions as a visible long flag.
Like Arg::alias, except that they are visible inside the help message.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.visible_alias("something-awesome")
.long("test")
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "--something-awesome", "coffee"
]);
assert_eq!(m.get_one::<String>("test").unwrap(), "coffee");sourcepub fn visible_short_alias(self, name: impl IntoResettable<char>) -> Self
pub fn visible_short_alias(self, name: impl IntoResettable<char>) -> Self
Add an alias, which functions as a visible short flag.
Like Arg::short_alias, except that they are visible inside the help message.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.long("test")
.visible_short_alias('t')
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "-t", "coffee"
]);
assert_eq!(m.get_one::<String>("test").unwrap(), "coffee");sourcepub fn visible_aliases(
self,
names: impl IntoIterator<Item = impl Into<Str>>
) -> Self
pub fn visible_aliases(
self,
names: impl IntoIterator<Item = impl Into<Str>>
) -> Self
Add aliases, which function as visible long flags.
Like Arg::aliases, except that they are visible inside the help message.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.long("test")
.action(ArgAction::SetTrue)
.visible_aliases(["something", "awesome", "cool"]))
.get_matches_from(vec![
"prog", "--awesome"
]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);sourcepub fn visible_short_aliases(self, names: impl IntoIterator<Item = char>) -> Self
pub fn visible_short_aliases(self, names: impl IntoIterator<Item = char>) -> Self
Add aliases, which function as visible short flags.
Like Arg::short_aliases, except that they are visible inside the help message.
Examples
let m = Command::new("prog")
.arg(Arg::new("test")
.long("test")
.action(ArgAction::SetTrue)
.visible_short_aliases(['t', 'e']))
.get_matches_from(vec![
"prog", "-t"
]);
assert_eq!(*m.get_one::<bool>("test").expect("defaulted by clap"), true);sourcepub fn index(self, idx: impl IntoResettable<usize>) -> Self
pub fn index(self, idx: impl IntoResettable<usize>) -> Self
Specifies the index of a positional argument starting at 1.
NOTE: The index refers to position according to other positional argument. It does not define position in the argument list as a whole.
NOTE: You can optionally leave off the index method, and the index will be
assigned in order of evaluation. Utilizing the index method allows for setting
indexes out of order
NOTE: This is only meant to be used for positional arguments and shouldn’t to be used
with Arg::short or Arg::long.
NOTE: When utilized with [Arg::num_args(1..)], only the last positional argument
may be defined as having a variable number of arguments (i.e. with the highest index)
Panics
Command will panic! if indexes are skipped (such as defining index(1) and index(3)
but not index(2), or a positional argument is defined as multiple and is not the highest
index
Examples
Arg::new("config")
.index(1)let m = Command::new("prog")
.arg(Arg::new("mode")
.index(1))
.arg(Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue))
.get_matches_from(vec![
"prog", "--debug", "fast"
]);
assert!(m.contains_id("mode"));
assert_eq!(m.get_one::<String>("mode").unwrap(), "fast"); // notice index(1) means "first positional"
// *not* first argumentsourcepub fn trailing_var_arg(self, yes: bool) -> Self
pub fn trailing_var_arg(self, yes: bool) -> Self
This is a “VarArg” and everything that follows should be captured by it, as if the user had
used a --.
NOTE: To start the trailing “VarArg” on unknown flags (and not just a positional
value), set allow_hyphen_values. Either way, users still
have the option to explicitly escape ambiguous arguments with --.
NOTE: Arg::value_delimiter still applies if set.
NOTE: Setting this requires Arg::num_args(..).
Examples
let m = Command::new("myprog")
.arg(arg!(<cmd> ... "commands to run").trailing_var_arg(true))
.get_matches_from(vec!["myprog", "arg1", "-r", "val1"]);
let trail: Vec<_> = m.get_many::<String>("cmd").unwrap().collect();
assert_eq!(trail, ["arg1", "-r", "val1"]);Examples found in repository?
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}sourcepub fn last(self, yes: bool) -> Self
pub fn last(self, yes: bool) -> Self
This arg is the last, or final, positional argument (i.e. has the highest
index) and is only able to be accessed via the -- syntax (i.e. $ prog args -- last_arg).
Even, if no other arguments are left to parse, if the user omits the -- syntax
they will receive an UnknownArgument error. Setting an argument to .last(true) also
allows one to access this arg early using the -- syntax. Accessing an arg early, even with
the -- syntax is otherwise not possible.
NOTE: This will change the usage string to look like $ prog [OPTIONS] [-- <ARG>] if
ARG is marked as .last(true).
NOTE: This setting will imply crate::Command::dont_collapse_args_in_usage because failing
to set this can make the usage string very confusing.
NOTE: This setting only applies to positional arguments, and has no effect on OPTIONS
NOTE: Setting this requires taking values
CAUTION: Using this setting and having child subcommands is not
recommended with the exception of also using
crate::Command::args_conflicts_with_subcommands
(or crate::Command::subcommand_negates_reqs if the argument marked Last is also
marked Arg::required)
Examples
Arg::new("args")
.action(ArgAction::Set)
.last(true)Setting last ensures the arg has the highest index of all positional args
and requires that the -- syntax be used to access it early.
let res = Command::new("prog")
.arg(Arg::new("first"))
.arg(Arg::new("second"))
.arg(Arg::new("third")
.action(ArgAction::Set)
.last(true))
.try_get_matches_from(vec![
"prog", "one", "--", "three"
]);
assert!(res.is_ok());
let m = res.unwrap();
assert_eq!(m.get_one::<String>("third").unwrap(), "three");
assert_eq!(m.get_one::<String>("second"), None);Even if the positional argument marked Last is the only argument left to parse,
failing to use the -- syntax results in an error.
let res = Command::new("prog")
.arg(Arg::new("first"))
.arg(Arg::new("second"))
.arg(Arg::new("third")
.action(ArgAction::Set)
.last(true))
.try_get_matches_from(vec![
"prog", "one", "two", "three"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);Examples found in repository?
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}sourcepub fn required(self, yes: bool) -> Self
pub fn required(self, yes: bool) -> Self
Specifies that the argument must be present.
Required by default means it is required, when no other conflicting rules or overrides have been evaluated. Conflicting rules take precedence over being required.
Pro tip: Flags (i.e. not positional, or arguments that take values) shouldn’t be required by default. This is because if a flag were to be required, it should simply be implied. No additional information is required from user. Flags by their very nature are simply boolean on/off switches. The only time a user should be required to use a flag is if the operation is destructive in nature, and the user is essentially proving to you, “Yes, I know what I’m doing.”
Examples
Arg::new("config")
.required(true)Setting required requires that the argument be used at runtime.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required(true)
.action(ArgAction::Set)
.long("config"))
.try_get_matches_from(vec![
"prog", "--config", "file.conf",
]);
assert!(res.is_ok());Setting required and then not supplying that argument at runtime is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required(true)
.action(ArgAction::Set)
.long("config"))
.try_get_matches_from(vec![
"prog"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);Examples found in repository?
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
fn main() {
let matches = Command::new("MyApp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>")
.about("Does awesome things")
.arg(arg!(--two <VALUE>).required(true))
.arg(arg!(--one <VALUE>).required(true))
.get_matches();
println!(
"two: {:?}",
matches.get_one::<String>("two").expect("required")
);
println!(
"one: {:?}",
matches.get_one::<String>("one").expect("required")
);
}sourcepub fn requires(self, arg_id: impl IntoResettable<Id>) -> Self
pub fn requires(self, arg_id: impl IntoResettable<Id>) -> Self
Sets an argument that is required when this one is present
i.e. when using this argument, the following argument must be present.
NOTE: Conflicting rules and override rules take precedence over being required
Examples
Arg::new("config")
.requires("input")Setting Arg::requires(name) requires that the argument be used at runtime if the
defining argument is used. If the defining argument isn’t used, the other argument isn’t
required
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires("input")
.long("config"))
.arg(Arg::new("input"))
.try_get_matches_from(vec![
"prog"
]);
assert!(res.is_ok()); // We didn't use cfg, so input wasn't requiredSetting Arg::requires(name) and not supplying that argument is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires("input")
.long("config"))
.arg(Arg::new("input"))
.try_get_matches_from(vec![
"prog", "--config", "file.conf"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn exclusive(self, yes: bool) -> Self
pub fn exclusive(self, yes: bool) -> Self
This argument must be passed alone; it conflicts with all other arguments.
Examples
Arg::new("config")
.exclusive(true)Setting an exclusive argument and having any other arguments present at runtime is an error.
let res = Command::new("prog")
.arg(Arg::new("exclusive")
.action(ArgAction::Set)
.exclusive(true)
.long("exclusive"))
.arg(Arg::new("debug")
.long("debug"))
.arg(Arg::new("input"))
.try_get_matches_from(vec![
"prog", "--exclusive", "file.conf", "file.txt"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);Examples found in repository?
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}sourcepub fn global(self, yes: bool) -> Self
pub fn global(self, yes: bool) -> Self
Specifies that an argument can be matched to all child Subcommands.
NOTE: Global arguments only propagate down, not up (to parent commands), however their values once a user uses them will be propagated back up to parents. In effect, this means one should define all global arguments at the top level, however it doesn’t matter where the user uses the global argument.
Examples
Assume an application with two subcommands, and you’d like to define a
--verbose flag that can be called on any of the subcommands and parent, but you don’t
want to clutter the source with three duplicate Arg definitions.
let m = Command::new("prog")
.arg(Arg::new("verb")
.long("verbose")
.short('v')
.action(ArgAction::SetTrue)
.global(true))
.subcommand(Command::new("test"))
.subcommand(Command::new("do-stuff"))
.get_matches_from(vec![
"prog", "do-stuff", "--verbose"
]);
assert_eq!(m.subcommand_name(), Some("do-stuff"));
let sub_m = m.subcommand_matches("do-stuff").unwrap();
assert_eq!(*sub_m.get_one::<bool>("verb").expect("defaulted by clap"), true);source§impl Arg
impl Arg
sourcepub fn action(self, action: impl IntoResettable<ArgAction>) -> Self
pub fn action(self, action: impl IntoResettable<ArgAction>) -> Self
Specify how to react to an argument when parsing it.
ArgAction controls things like
- Overwriting previous values with new ones
- Appending new values to all previous ones
- Counting how many times a flag occurs
The default action is ArgAction::Set
Examples
let cmd = Command::new("mycmd")
.arg(
Arg::new("flag")
.long("flag")
.action(clap::ArgAction::Append)
);
let matches = cmd.try_get_matches_from(["mycmd", "--flag", "value"]).unwrap();
assert!(matches.contains_id("flag"));
assert_eq!(
matches.get_many::<String>("flag").unwrap_or_default().map(|v| v.as_str()).collect::<Vec<_>>(),
vec!["value"]
);Examples found in repository?
38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
fn augment_args(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}
fn augment_args_for_update(cmd: Command) -> Command {
cmd.arg(
Arg::new("foo")
.short('f')
.long("foo")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("bar")
.short('b')
.long("bar")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new("quuz")
.short('q')
.long("quuz")
.action(ArgAction::Set),
)
}More examples
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27
fn main() {
let cli = Command::new("CLI").arg(arg!(-b - -built).action(clap::ArgAction::SetTrue));
// Augment built args with derived args
let cli = DerivedArgs::augment_args(cli);
let matches = cli.get_matches();
println!("Value of built: {:?}", matches.get_flag("built"));
println!(
"Value of derived via ArgMatches: {:?}",
matches.get_flag("derived")
);
// Since DerivedArgs implements FromArgMatches, we can extract it from the unstructured ArgMatches.
// This is the main benefit of using derived arguments.
let derived_matches = DerivedArgs::from_arg_matches(&matches)
.map_err(|err| err.exit())
.unwrap();
println!("Value of derived: {:#?}", derived_matches);
}13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn value_parser(self, parser: impl IntoResettable<ValueParser>) -> Self
pub fn value_parser(self, parser: impl IntoResettable<ValueParser>) -> Self
Specify the typed behavior of the argument.
This allows parsing and validating a value before storing it into
ArgMatches as the given type.
Possible value parsers include:
value_parser!(T)for auto-selecting a value parser for a given type- Or range expressions like
0..=1as a shorthand forRangedI64ValueParser
- Or range expressions like
Fn(&str) -> Result<T, E>[&str]andPossibleValuesParserfor static enumerated valuesBoolishValueParser, andFalseyValueParserfor alternativeboolimplementationsNonEmptyStringValueParserfor basic validation for strings- or any other
TypedValueParserimplementation
The default value is ValueParser::string.
let mut cmd = clap::Command::new("raw")
.arg(
clap::Arg::new("color")
.long("color")
.value_parser(["always", "auto", "never"])
.default_value("auto")
)
.arg(
clap::Arg::new("hostname")
.long("hostname")
.value_parser(clap::builder::NonEmptyStringValueParser::new())
.action(ArgAction::Set)
.required(true)
)
.arg(
clap::Arg::new("port")
.long("port")
.value_parser(clap::value_parser!(u16).range(3000..))
.action(ArgAction::Set)
.required(true)
);
let m = cmd.try_get_matches_from_mut(
["cmd", "--hostname", "rust-lang.org", "--port", "3001"]
).unwrap();
let color: &String = m.get_one("color")
.expect("default");
assert_eq!(color, "auto");
let hostname: &String = m.get_one("hostname")
.expect("required");
assert_eq!(hostname, "rust-lang.org");
let port: u16 = *m.get_one("port")
.expect("required");
assert_eq!(port, 3001);Examples found in repository?
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}More examples
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}sourcepub fn num_args(self, qty: impl IntoResettable<ValueRange>) -> Self
pub fn num_args(self, qty: impl IntoResettable<ValueRange>) -> Self
Specifies the number of arguments parsed per occurrence
For example, if you had a -f <file> argument where you wanted exactly 3 ‘files’ you would
set .num_args(3), and this argument wouldn’t be satisfied unless the user
provided 3 and only 3 values.
Users may specify values for arguments in any of the following methods
- Using a space such as
-o valueor--option value - Using an equals and no space such as
-o=valueor--option=value - Use a short and no space such as
-ovalue
WARNING:
Setting a variable number of values (e.g. 1..=10) for an argument without
other details can be dangerous in some circumstances. Because multiple values are
allowed, --option val1 val2 val3 is perfectly valid. Be careful when designing a CLI
where positional arguments or subcommands are also expected as clap will continue
parsing values until one of the following happens:
- It reaches the maximum number of values
- It reaches a specific number of values
- It finds another flag or option (i.e. something that starts with a
-) - It reaches the
Arg::value_terminatorif set
Alternatively,
- Use a delimiter between values with Arg::value_delimiter
- Require a flag occurrence per value with
ArgAction::Append - Require positional arguments to appear after
--withArg::last
Examples
Option:
let m = Command::new("prog")
.arg(Arg::new("mode")
.long("mode")
.num_args(1))
.get_matches_from(vec![
"prog", "--mode", "fast"
]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "fast");Flag/option hybrid (see also default_missing_value)
let cmd = Command::new("prog")
.arg(Arg::new("mode")
.long("mode")
.default_missing_value("slow")
.default_value("plaid")
.num_args(0..=1));
let m = cmd.clone()
.get_matches_from(vec![
"prog", "--mode", "fast"
]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "fast");
let m = cmd.clone()
.get_matches_from(vec![
"prog", "--mode",
]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "slow");
let m = cmd.clone()
.get_matches_from(vec![
"prog",
]);
assert_eq!(m.get_one::<String>("mode").unwrap(), "plaid");Tuples
let cmd = Command::new("prog")
.arg(Arg::new("file")
.action(ArgAction::Set)
.num_args(2)
.short('F'));
let m = cmd.clone()
.get_matches_from(vec![
"prog", "-F", "in-file", "out-file"
]);
assert_eq!(
m.get_many::<String>("file").unwrap_or_default().map(|v| v.as_str()).collect::<Vec<_>>(),
vec!["in-file", "out-file"]
);
let res = cmd.clone()
.try_get_matches_from(vec![
"prog", "-F", "file1"
]);
assert_eq!(res.unwrap_err().kind(), ErrorKind::WrongNumberOfValues);A common mistake is to define an option which allows multiple values and a positional argument.
let cmd = Command::new("prog")
.arg(Arg::new("file")
.action(ArgAction::Set)
.num_args(0..)
.short('F'))
.arg(Arg::new("word"));
let m = cmd.clone().get_matches_from(vec![
"prog", "-F", "file1", "file2", "file3", "word"
]);
let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3", "word"]); // wait...what?!
assert!(!m.contains_id("word")); // but we clearly used word!
// but this works
let m = cmd.clone().get_matches_from(vec![
"prog", "word", "-F", "file1", "file2", "file3",
]);
let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3"]);
assert_eq!(m.get_one::<String>("word").unwrap(), "word");The problem is clap doesn’t know when to stop parsing values for “file”.
A solution for the example above is to limit how many values with a maximum, or specific
number, or to say ArgAction::Append is ok, but multiple values are not.
let m = Command::new("prog")
.arg(Arg::new("file")
.action(ArgAction::Append)
.short('F'))
.arg(Arg::new("word"))
.get_matches_from(vec![
"prog", "-F", "file1", "-F", "file2", "-F", "file3", "word"
]);
let files: Vec<_> = m.get_many::<String>("file").unwrap().collect();
assert_eq!(files, ["file1", "file2", "file3"]);
assert_eq!(m.get_one::<String>("word").unwrap(), "word");Examples found in repository?
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53
fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}More examples
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn value_name(self, name: impl IntoResettable<Str>) -> Self
pub fn value_name(self, name: impl IntoResettable<Str>) -> Self
Placeholder for the argument’s value in the help message / usage.
This name is cosmetic only; the name is not used to access arguments.
This setting can be very helpful when describing the type of input the user should be
using, such as FILE, INTERFACE, etc. Although not required, it’s somewhat convention to
use all capital letters for the value name.
NOTE: implicitly sets Arg::action(ArgAction::Set)
Examples
Arg::new("cfg")
.long("config")
.value_name("FILE")let m = Command::new("prog")
.arg(Arg::new("config")
.long("config")
.value_name("FILE")
.help("Some help text"))
.get_matches_from(vec![
"prog", "--help"
]);Running the above program produces the following output
valnames
Usage: valnames [OPTIONS]
Options:
--config <FILE> Some help text
-h, --help Print help information
-V, --version Print version informationsourcepub fn value_names(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self
pub fn value_names(self, names: impl IntoIterator<Item = impl Into<Str>>) -> Self
Placeholders for the argument’s values in the help message / usage.
These names are cosmetic only, used for help and usage strings only. The names are not
used to access arguments. The values of the arguments are accessed in numeric order (i.e.
if you specify two names one and two one will be the first matched value, two will
be the second).
This setting can be very helpful when describing the type of input the user should be
using, such as FILE, INTERFACE, etc. Although not required, it’s somewhat convention to
use all capital letters for the value name.
Pro Tip: It may help to use Arg::next_line_help(true) if there are long, or
multiple value names in order to not throw off the help text alignment of all options.
NOTE: implicitly sets Arg::action(ArgAction::Set) and Arg::num_args(1..).
Examples
Arg::new("speed")
.short('s')
.value_names(["fast", "slow"]);let m = Command::new("prog")
.arg(Arg::new("io")
.long("io-files")
.value_names(["INFILE", "OUTFILE"]))
.get_matches_from(vec![
"prog", "--help"
]);Running the above program produces the following output
valnames
Usage: valnames [OPTIONS]
Options:
-h, --help Print help information
--io-files <INFILE> <OUTFILE> Some help text
-V, --version Print version informationsourcepub fn value_hint(self, value_hint: impl IntoResettable<ValueHint>) -> Self
pub fn value_hint(self, value_hint: impl IntoResettable<ValueHint>) -> Self
Provide the shell a hint about how to complete this argument.
See ValueHint for more information.
NOTE: implicitly sets [Arg::action(ArgAction::Set)].
For example, to take a username as argument:
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username);To take a full command line and its arguments (for example, when writing a command wrapper):
Command::new("prog")
.trailing_var_arg(true)
.arg(
Arg::new("command")
.action(ArgAction::Set)
.num_args(1..)
.value_hint(ValueHint::CommandWithArguments)
);Examples found in repository?
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95
fn build_cli() -> Command {
let value_hint_command = Command::new("value-hint")
.visible_alias("hint")
.arg(
Arg::new("unknown")
.long("unknown")
.value_hint(ValueHint::Unknown),
)
.arg(Arg::new("other").long("other").value_hint(ValueHint::Other))
.arg(
Arg::new("path")
.long("path")
.short('p')
.value_hint(ValueHint::AnyPath),
)
.arg(
Arg::new("file")
.long("file")
.short('f')
.value_hint(ValueHint::FilePath),
)
.arg(
Arg::new("dir")
.long("dir")
.short('d')
.value_hint(ValueHint::DirPath),
)
.arg(
Arg::new("exe")
.long("exe")
.short('e')
.value_hint(ValueHint::ExecutablePath),
)
.arg(
Arg::new("cmd_name")
.long("cmd-name")
.value_hint(ValueHint::CommandName),
)
.arg(
Arg::new("cmd")
.long("cmd")
.short('c')
.value_hint(ValueHint::CommandString),
)
.arg(
Arg::new("command_with_args")
.num_args(1..)
// AppSettings::TrailingVarArg is required to use ValueHint::CommandWithArguments
.trailing_var_arg(true)
.value_hint(ValueHint::CommandWithArguments),
)
.arg(
Arg::new("user")
.short('u')
.long("user")
.value_hint(ValueHint::Username),
)
.arg(
Arg::new("host")
.long("host")
.value_hint(ValueHint::Hostname),
)
.arg(Arg::new("url").long("url").value_hint(ValueHint::Url))
.arg(
Arg::new("email")
.long("email")
.value_hint(ValueHint::EmailAddress),
);
Command::new("completion")
.arg(
Arg::new("generator")
.long("generate")
.value_parser(value_parser!(Shell)),
)
.subcommand(value_hint_command)
}sourcepub fn ignore_case(self, yes: bool) -> Self
pub fn ignore_case(self, yes: bool) -> Self
Match values against PossibleValuesParser without matching case.
When other arguments are conditionally required based on the
value of a case-insensitive argument, the equality check done
by Arg::required_if_eq, Arg::required_if_eq_any, or
Arg::required_if_eq_all is case-insensitive.
NOTE: Setting this requires taking values
NOTE: To do unicode case folding, enable the unicode feature flag.
Examples
let m = Command::new("pv")
.arg(Arg::new("option")
.long("option")
.action(ArgAction::Set)
.ignore_case(true)
.value_parser(["test123"]))
.get_matches_from(vec![
"pv", "--option", "TeSt123",
]);
assert!(m.get_one::<String>("option").unwrap().eq_ignore_ascii_case("test123"));This setting also works when multiple values can be defined:
let m = Command::new("pv")
.arg(Arg::new("option")
.short('o')
.long("option")
.action(ArgAction::Set)
.ignore_case(true)
.num_args(1..)
.value_parser(["test123", "test321"]))
.get_matches_from(vec![
"pv", "--option", "TeSt123", "teST123", "tESt321"
]);
let matched_vals = m.get_many::<String>("option").unwrap().collect::<Vec<_>>();
assert_eq!(&*matched_vals, &["TeSt123", "teST123", "tESt321"]);sourcepub fn allow_hyphen_values(self, yes: bool) -> Self
pub fn allow_hyphen_values(self, yes: bool) -> Self
Allows values which start with a leading hyphen (-)
To limit values to just numbers, see
allow_negative_numbers.
See also trailing_var_arg.
NOTE: Setting this requires taking values
WARNING: Prior arguments with allow_hyphen_values(true) get precedence over known
flags but known flags get precedence over the next possible positional argument with
allow_hyphen_values(true). When combined with [Arg::num_args(..)],
Arg::value_terminator is one way to ensure processing stops.
WARNING: Take caution when using this setting combined with another argument using
Arg::num_args, as this becomes ambiguous $ prog --arg -- -- val. All
three --, --, val will be values when the user may have thought the second -- would
constitute the normal, “Only positional args follow” idiom.
Examples
let m = Command::new("prog")
.arg(Arg::new("pat")
.action(ArgAction::Set)
.allow_hyphen_values(true)
.long("pattern"))
.get_matches_from(vec![
"prog", "--pattern", "-file"
]);
assert_eq!(m.get_one::<String>("pat").unwrap(), "-file");Not setting Arg::allow_hyphen_values(true) and supplying a value which starts with a
hyphen is an error.
let res = Command::new("prog")
.arg(Arg::new("pat")
.action(ArgAction::Set)
.long("pattern"))
.try_get_matches_from(vec![
"prog", "--pattern", "-file"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::UnknownArgument);sourcepub fn allow_negative_numbers(self, yes: bool) -> Self
pub fn allow_negative_numbers(self, yes: bool) -> Self
Allows negative numbers to pass as values.
This is similar to Arg::allow_hyphen_values except that it only allows numbers,
all other undefined leading hyphens will fail to parse.
NOTE: Setting this requires taking values
Examples
let res = Command::new("myprog")
.arg(Arg::new("num").allow_negative_numbers(true))
.try_get_matches_from(vec![
"myprog", "-20"
]);
assert!(res.is_ok());
let m = res.unwrap();
assert_eq!(m.get_one::<String>("num").unwrap(), "-20");sourcepub fn require_equals(self, yes: bool) -> Self
pub fn require_equals(self, yes: bool) -> Self
Requires that options use the --option=val syntax
i.e. an equals between the option and associated value.
NOTE: Setting this requires taking values
Examples
Setting require_equals requires that the option have an equals sign between
it and the associated value.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.require_equals(true)
.long("config"))
.try_get_matches_from(vec![
"prog", "--config=file.conf"
]);
assert!(res.is_ok());Setting require_equals and not supplying the equals will cause an
error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.require_equals(true)
.long("config"))
.try_get_matches_from(vec![
"prog", "--config", "file.conf"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::NoEquals);Examples found in repository?
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fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}sourcepub fn value_delimiter(self, d: impl IntoResettable<char>) -> Self
pub fn value_delimiter(self, d: impl IntoResettable<char>) -> Self
Allow grouping of multiple values via a delimiter.
i.e. should --option=val1,val2,val3 be parsed as three values (val1, val2,
and val3) or as a single value (val1,val2,val3). Defaults to using , (comma) as the
value delimiter for all arguments that accept values (options and positional arguments)
NOTE: implicitly sets Arg::action(ArgAction::Set)
Examples
let m = Command::new("prog")
.arg(Arg::new("config")
.short('c')
.long("config")
.value_delimiter(','))
.get_matches_from(vec![
"prog", "--config=val1,val2,val3"
]);
assert_eq!(m.get_many::<String>("config").unwrap().collect::<Vec<_>>(), ["val1", "val2", "val3"])sourcepub fn value_terminator(self, term: impl IntoResettable<Str>) -> Self
pub fn value_terminator(self, term: impl IntoResettable<Str>) -> Self
Sentinel to stop parsing multiple values of a given argument.
By default when
one sets num_args(1..) on an argument, clap will continue parsing values for that
argument until it reaches another valid argument, or one of the other more specific settings
for multiple values is used (such as num_args).
NOTE: This setting only applies to options and positional arguments
NOTE: When the terminator is passed in on the command line, it is not stored as one of the values
Examples
Arg::new("vals")
.action(ArgAction::Set)
.num_args(1..)
.value_terminator(";")The following example uses two arguments, a sequence of commands, and the location in which to perform them
let m = Command::new("prog")
.arg(Arg::new("cmds")
.action(ArgAction::Set)
.num_args(1..)
.allow_hyphen_values(true)
.value_terminator(";"))
.arg(Arg::new("location"))
.get_matches_from(vec![
"prog", "find", "-type", "f", "-name", "special", ";", "/home/clap"
]);
let cmds: Vec<_> = m.get_many::<String>("cmds").unwrap().collect();
assert_eq!(&cmds, &["find", "-type", "f", "-name", "special"]);
assert_eq!(m.get_one::<String>("location").unwrap(), "/home/clap");sourcepub fn raw(self, yes: bool) -> Self
pub fn raw(self, yes: bool) -> Self
Consume all following arguments.
Do not be parse them individually, but rather pass them in entirety.
It is worth noting that setting this requires all values to come after a -- to indicate
they should all be captured. For example:
--foo something -- -v -v -v -b -b -b --baz -q -u -xWill result in everything after -- to be considered one raw argument. This behavior
may not be exactly what you are expecting and using crate::Command::trailing_var_arg
may be more appropriate.
NOTE: Implicitly sets Arg::action(ArgAction::Set) Arg::num_args(1..),
Arg::allow_hyphen_values(true), and Arg::last(true) when set to true.
sourcepub fn default_value(self, val: impl IntoResettable<OsStr>) -> Self
pub fn default_value(self, val: impl IntoResettable<OsStr>) -> Self
Value for the argument when not present.
NOTE: If the user does not use this argument at runtime ArgMatches::contains_id will
still return true. If you wish to determine whether the argument was used at runtime or
not, consider ArgMatches::value_source.
NOTE: This setting is perfectly compatible with Arg::default_value_if but slightly
different. Arg::default_value only takes effect when the user has not provided this arg
at runtime. Arg::default_value_if however only takes effect when the user has not provided
a value at runtime and these other conditions are met as well. If you have set
Arg::default_value and Arg::default_value_if, and the user did not provide this arg
at runtime, nor were the conditions met for Arg::default_value_if, the Arg::default_value
will be applied.
NOTE: This implicitly sets Arg::action(ArgAction::Set).
Examples
First we use the default value without providing any value at runtime.
let m = Command::new("prog")
.arg(Arg::new("opt")
.long("myopt")
.default_value("myval"))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("opt").unwrap(), "myval");
assert!(m.contains_id("opt"));
assert_eq!(m.value_source("opt"), Some(ValueSource::DefaultValue));Next we provide a value at runtime to override the default.
let m = Command::new("prog")
.arg(Arg::new("opt")
.long("myopt")
.default_value("myval"))
.get_matches_from(vec![
"prog", "--myopt=non_default"
]);
assert_eq!(m.get_one::<String>("opt").unwrap(), "non_default");
assert!(m.contains_id("opt"));
assert_eq!(m.value_source("opt"), Some(ValueSource::CommandLine));Examples found in repository?
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
fn main() -> Result<(), std::io::Error> {
let cmd = Command::new("myapp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>:Ola Nordmann <old@nordmann.no>")
.about("Does awesome things")
.long_about(
"With a longer description to help clarify some things.
And a few newlines.",
)
.after_help("This is an extra section added to the end of the manpage.")
.after_long_help("With even more text added.")
.arg(
arg!(-c --config <FILE> "Sets a custom config file")
.long_help("Some more text about how to set a custom config file")
.default_value("config.toml")
.env("CONFIG_FILE"),
)
.arg(arg!([output] "Sets an output file").default_value("result.txt"))
.arg(
arg!(-d --debug ... "Turn debugging information on")
.env("DEBUG_ON")
.hide_env(true),
)
.subcommand(
Command::new("test")
.about("does testing things")
.arg(arg!(-l --list "Lists test values")),
);
Man::new(cmd).render(&mut io::stdout())
}More examples
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fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}sourcepub fn default_values(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
pub fn default_values(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
Value for the argument when not present.
See Arg::default_value.
sourcepub fn default_missing_value(self, val: impl IntoResettable<OsStr>) -> Self
pub fn default_missing_value(self, val: impl IntoResettable<OsStr>) -> Self
Value for the argument when the flag is present but no value is specified.
This configuration option is often used to give the user a shortcut and allow them to
efficiently specify an option argument without requiring an explicitly value. The --color
argument is a common example. By, supplying an default, such as default_missing_value("always"),
the user can quickly just add --color to the command line to produce the desired color output.
NOTE: using this configuration option requires the use of the
.num_args(0..N) and the
.require_equals(true) configuration option. These are required in
order to unambiguously determine what, if any, value was supplied for the argument.
Examples
For POSIX style --color:
fn cli() -> Command {
Command::new("prog")
.arg(Arg::new("color").long("color")
.value_name("WHEN")
.value_parser(["always", "auto", "never"])
.default_value("auto")
.num_args(0..=1)
.require_equals(true)
.default_missing_value("always")
.help("Specify WHEN to colorize output.")
)
}
// first, we'll provide no arguments
let m = cli().get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("color").unwrap(), "auto");
assert_eq!(m.value_source("color"), Some(ValueSource::DefaultValue));
// next, we'll provide a runtime value to override the default (as usually done).
let m = cli().get_matches_from(vec![
"prog", "--color=never"
]);
assert_eq!(m.get_one::<String>("color").unwrap(), "never");
assert_eq!(m.value_source("color"), Some(ValueSource::CommandLine));
// finally, we will use the shortcut and only provide the argument without a value.
let m = cli().get_matches_from(vec![
"prog", "--color"
]);
assert_eq!(m.get_one::<String>("color").unwrap(), "always");
assert_eq!(m.value_source("color"), Some(ValueSource::CommandLine));For bool literals:
fn cli() -> Command {
Command::new("prog")
.arg(Arg::new("create").long("create")
.value_name("BOOL")
.value_parser(value_parser!(bool))
.num_args(0..=1)
.require_equals(true)
.default_missing_value("true")
)
}
// first, we'll provide no arguments
let m = cli().get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<bool>("create").copied(), None);
// next, we'll provide a runtime value to override the default (as usually done).
let m = cli().get_matches_from(vec![
"prog", "--create=false"
]);
assert_eq!(m.get_one::<bool>("create").copied(), Some(false));
assert_eq!(m.value_source("create"), Some(ValueSource::CommandLine));
// finally, we will use the shortcut and only provide the argument without a value.
let m = cli().get_matches_from(vec![
"prog", "--create"
]);
assert_eq!(m.get_one::<bool>("create").copied(), Some(true));
assert_eq!(m.value_source("create"), Some(ValueSource::CommandLine));Examples found in repository?
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}More examples
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fn cli() -> Command {
Command::new("git")
.about("A fictional versioning CLI")
.subcommand_required(true)
.arg_required_else_help(true)
.allow_external_subcommands(true)
.subcommand(
Command::new("clone")
.about("Clones repos")
.arg(arg!(<REMOTE> "The remote to clone"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("diff")
.about("Compare two commits")
.arg(arg!(base: [COMMIT]))
.arg(arg!(head: [COMMIT]))
.arg(arg!(path: [PATH]).last(true))
.arg(
arg!(--color <WHEN>)
.value_parser(["always", "auto", "never"])
.num_args(0..=1)
.require_equals(true)
.default_value("auto")
.default_missing_value("always"),
),
)
.subcommand(
Command::new("push")
.about("pushes things")
.arg(arg!(<REMOTE> "The remote to target"))
.arg_required_else_help(true),
)
.subcommand(
Command::new("add")
.about("adds things")
.arg_required_else_help(true)
.arg(arg!(<PATH> ... "Stuff to add").value_parser(clap::value_parser!(PathBuf))),
)
.subcommand(
Command::new("stash")
.args_conflicts_with_subcommands(true)
.args(push_args())
.subcommand(Command::new("push").args(push_args()))
.subcommand(Command::new("pop").arg(arg!([STASH])))
.subcommand(Command::new("apply").arg(arg!([STASH]))),
)
}sourcepub fn default_missing_value_os(self, val: impl Into<OsStr>) -> Self
pub fn default_missing_value_os(self, val: impl Into<OsStr>) -> Self
Value for the argument when the flag is present but no value is specified.
sourcepub fn default_missing_values(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
pub fn default_missing_values(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
Value for the argument when the flag is present but no value is specified.
sourcepub fn default_missing_values_os(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
pub fn default_missing_values_os(
self,
vals: impl IntoIterator<Item = impl Into<OsStr>>
) -> Self
Value for the argument when the flag is present but no value is specified.
sourcepub fn env(self, name: impl IntoResettable<OsStr>) -> Self
pub fn env(self, name: impl IntoResettable<OsStr>) -> Self
Read from name environment variable when argument is not present.
If it is not present in the environment, then default rules will apply.
If user sets the argument in the environment:
- When
Arg::action(ArgAction::Set)is not set, the flag is considered raised. - When
Arg::action(ArgAction::Set)is set,ArgMatches::get_onewill return value of the environment variable.
If user doesn’t set the argument in the environment:
- When
Arg::action(ArgAction::Set)is not set, the flag is considered off. - When
Arg::action(ArgAction::Set)is set,ArgMatches::get_onewill return the default specified.
Examples
In this example, we show the variable coming from the environment:
env::set_var("MY_FLAG", "env");
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.env("MY_FLAG")
.action(ArgAction::Set))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("flag").unwrap(), "env");In this example, because prog is a flag that accepts an optional, case-insensitive
boolean literal.
Note that the value parser controls how flags are parsed. In this case we’ve selected
FalseyValueParser. A false literal is n, no,
f, false, off or 0. An absent environment variable will also be considered as
false. Anything else will considered as true.
env::set_var("TRUE_FLAG", "true");
env::set_var("FALSE_FLAG", "0");
let m = Command::new("prog")
.arg(Arg::new("true_flag")
.long("true_flag")
.action(ArgAction::SetTrue)
.value_parser(FalseyValueParser::new())
.env("TRUE_FLAG"))
.arg(Arg::new("false_flag")
.long("false_flag")
.action(ArgAction::SetTrue)
.value_parser(FalseyValueParser::new())
.env("FALSE_FLAG"))
.arg(Arg::new("absent_flag")
.long("absent_flag")
.action(ArgAction::SetTrue)
.value_parser(FalseyValueParser::new())
.env("ABSENT_FLAG"))
.get_matches_from(vec![
"prog"
]);
assert!(*m.get_one::<bool>("true_flag").unwrap());
assert!(!*m.get_one::<bool>("false_flag").unwrap());
assert!(!*m.get_one::<bool>("absent_flag").unwrap());In this example, we show the variable coming from an option on the CLI:
env::set_var("MY_FLAG", "env");
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.env("MY_FLAG")
.action(ArgAction::Set))
.get_matches_from(vec![
"prog", "--flag", "opt"
]);
assert_eq!(m.get_one::<String>("flag").unwrap(), "opt");In this example, we show the variable coming from the environment even with the presence of a default:
env::set_var("MY_FLAG", "env");
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.env("MY_FLAG")
.action(ArgAction::Set)
.default_value("default"))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("flag").unwrap(), "env");In this example, we show the use of multiple values in a single environment variable:
env::set_var("MY_FLAG_MULTI", "env1,env2");
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.env("MY_FLAG_MULTI")
.action(ArgAction::Set)
.num_args(1..)
.value_delimiter(','))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_many::<String>("flag").unwrap().collect::<Vec<_>>(), vec!["env1", "env2"]);Examples found in repository?
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
fn main() -> Result<(), std::io::Error> {
let cmd = Command::new("myapp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>:Ola Nordmann <old@nordmann.no>")
.about("Does awesome things")
.long_about(
"With a longer description to help clarify some things.
And a few newlines.",
)
.after_help("This is an extra section added to the end of the manpage.")
.after_long_help("With even more text added.")
.arg(
arg!(-c --config <FILE> "Sets a custom config file")
.long_help("Some more text about how to set a custom config file")
.default_value("config.toml")
.env("CONFIG_FILE"),
)
.arg(arg!([output] "Sets an output file").default_value("result.txt"))
.arg(
arg!(-d --debug ... "Turn debugging information on")
.env("DEBUG_ON")
.hide_env(true),
)
.subcommand(
Command::new("test")
.about("does testing things")
.arg(arg!(-l --list "Lists test values")),
);
Man::new(cmd).render(&mut io::stdout())
}source§impl Arg
impl Arg
sourcepub fn help(self, h: impl IntoResettable<StyledStr>) -> Self
pub fn help(self, h: impl IntoResettable<StyledStr>) -> Self
Sets the description of the argument for short help (-h).
Typically, this is a short (one line) description of the arg.
If Arg::long_help is not specified, this message will be displayed for --help.
NOTE: Only Arg::help is used in completion script generation in order to be concise
Examples
Any valid UTF-8 is allowed in the help text. The one exception is when one wishes to include a newline in the help text and have the following text be properly aligned with all the other help text.
Setting help displays a short message to the side of the argument when the user passes
-h or --help (by default).
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays
helptest
Usage: helptest [OPTIONS]
Options:
--config Some help text describing the --config arg
-h, --help Print help information
-V, --version Print version informationExamples found in repository?
13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
fn main() {
let cmd = Command::new(env!("CARGO_CRATE_NAME"))
.multicall(true)
.subcommand(
Command::new("busybox")
.arg_required_else_help(true)
.subcommand_value_name("APPLET")
.subcommand_help_heading("APPLETS")
.arg(
Arg::new("install")
.long("install")
.help("Install hardlinks for all subcommands in path")
.exclusive(true)
.action(ArgAction::Set)
.default_missing_value("/usr/local/bin")
.value_parser(value_parser!(PathBuf)),
)
.subcommands(applet_commands()),
)
.subcommands(applet_commands());
let matches = cmd.get_matches();
let mut subcommand = matches.subcommand();
if let Some(("busybox", cmd)) = subcommand {
if cmd.contains_id("install") {
unimplemented!("Make hardlinks to the executable here");
}
subcommand = cmd.subcommand();
}
match subcommand {
Some(("false", _)) => exit(1),
Some(("true", _)) => exit(0),
_ => unreachable!("parser should ensure only valid subcommand names are used"),
}
}More examples
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn long_help(self, h: impl IntoResettable<StyledStr>) -> Self
pub fn long_help(self, h: impl IntoResettable<StyledStr>) -> Self
Sets the description of the argument for long help (--help).
Typically this a more detailed (multi-line) message that describes the arg.
If Arg::help is not specified, this message will be displayed for -h.
NOTE: Only Arg::help is used in completion script generation in order to be concise
Examples
Any valid UTF-8 is allowed in the help text. The one exception is when one wishes to include a newline in the help text and have the following text be properly aligned with all the other help text.
Setting help displays a short message to the side of the argument when the user passes
-h or --help (by default).
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.long_help(
"The config file used by the myprog must be in JSON format
with only valid keys and may not contain other nonsense
that cannot be read by this program. Obviously I'm going on
and on, so I'll stop now."))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays
prog
Usage: prog [OPTIONS]
Options:
--config
The config file used by the myprog must be in JSON format
with only valid keys and may not contain other nonsense
that cannot be read by this program. Obviously I'm going on
and on, so I'll stop now.
-h, --help
Print help information
-V, --version
Print version informationExamples found in repository?
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
fn main() -> Result<(), std::io::Error> {
let cmd = Command::new("myapp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>:Ola Nordmann <old@nordmann.no>")
.about("Does awesome things")
.long_about(
"With a longer description to help clarify some things.
And a few newlines.",
)
.after_help("This is an extra section added to the end of the manpage.")
.after_long_help("With even more text added.")
.arg(
arg!(-c --config <FILE> "Sets a custom config file")
.long_help("Some more text about how to set a custom config file")
.default_value("config.toml")
.env("CONFIG_FILE"),
)
.arg(arg!([output] "Sets an output file").default_value("result.txt"))
.arg(
arg!(-d --debug ... "Turn debugging information on")
.env("DEBUG_ON")
.hide_env(true),
)
.subcommand(
Command::new("test")
.about("does testing things")
.arg(arg!(-l --list "Lists test values")),
);
Man::new(cmd).render(&mut io::stdout())
}sourcepub fn display_order(self, ord: impl IntoResettable<usize>) -> Self
pub fn display_order(self, ord: impl IntoResettable<usize>) -> Self
Allows custom ordering of args within the help message.
Args with a lower value will be displayed first in the help message. This is helpful when one would like to emphasise frequently used args, or prioritize those towards the top of the list. Args with duplicate display orders will be displayed in alphabetical order.
NOTE: The default is 999 for all arguments.
NOTE: This setting is ignored for positional arguments which are always displayed in index order.
Examples
let m = Command::new("prog")
.arg(Arg::new("a") // Typically args are grouped alphabetically by name.
// Args without a display_order have a value of 999 and are
// displayed alphabetically with all other 999 valued args.
.long("long-option")
.short('o')
.action(ArgAction::Set)
.help("Some help and text"))
.arg(Arg::new("b")
.long("other-option")
.short('O')
.action(ArgAction::Set)
.display_order(1) // In order to force this arg to appear *first*
// all we have to do is give it a value lower than 999.
// Any other args with a value of 1 will be displayed
// alphabetically with this one...then 2 values, then 3, etc.
.help("I should be first!"))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays the following help message
cust-ord
Usage: cust-ord [OPTIONS]
Options:
-h, --help Print help information
-V, --version Print version information
-O, --other-option <b> I should be first!
-o, --long-option <a> Some help and textsourcepub fn help_heading(self, heading: impl IntoResettable<Str>) -> Self
pub fn help_heading(self, heading: impl IntoResettable<Str>) -> Self
Override the current help section.
sourcepub fn next_line_help(self, yes: bool) -> Self
pub fn next_line_help(self, yes: bool) -> Self
Render the help on the line after the argument.
This can be helpful for arguments with very long or complex help messages. This can also be helpful for arguments with very long flag names, or many/long value names.
NOTE: To apply this setting to all arguments and subcommands, consider using
crate::Command::next_line_help
Examples
let m = Command::new("prog")
.arg(Arg::new("opt")
.long("long-option-flag")
.short('o')
.action(ArgAction::Set)
.next_line_help(true)
.value_names(["value1", "value2"])
.help("Some really long help and complex\n\
help that makes more sense to be\n\
on a line after the option"))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays the following help message
nlh
Usage: nlh [OPTIONS]
Options:
-h, --help Print help information
-V, --version Print version information
-o, --long-option-flag <value1> <value2>
Some really long help and complex
help that makes more sense to be
on a line after the optionsourcepub fn hide(self, yes: bool) -> Self
pub fn hide(self, yes: bool) -> Self
Do not display the argument in help message.
NOTE: This does not hide the argument from usage strings on error
Examples
Setting Hidden will hide the argument when displaying help text
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.hide(true)
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays
helptest
Usage: helptest [OPTIONS]
Options:
-h, --help Print help information
-V, --version Print version informationsourcepub fn hide_possible_values(self, yes: bool) -> Self
pub fn hide_possible_values(self, yes: bool) -> Self
Do not display the possible values in the help message.
This is useful for args with many values, or ones which are explained elsewhere in the help text.
NOTE: Setting this requires taking values
To set this for all arguments, see
Command::hide_possible_values.
Examples
let m = Command::new("prog")
.arg(Arg::new("mode")
.long("mode")
.value_parser(["fast", "slow"])
.action(ArgAction::Set)
.hide_possible_values(true));If we were to run the above program with --help the [values: fast, slow] portion of
the help text would be omitted.
sourcepub fn hide_default_value(self, yes: bool) -> Self
pub fn hide_default_value(self, yes: bool) -> Self
Do not display the default value of the argument in the help message.
This is useful when default behavior of an arg is explained elsewhere in the help text.
NOTE: Setting this requires taking values
Examples
let m = Command::new("connect")
.arg(Arg::new("host")
.long("host")
.default_value("localhost")
.action(ArgAction::Set)
.hide_default_value(true));
If we were to run the above program with --help the [default: localhost] portion of
the help text would be omitted.
sourcepub fn hide_env(self, yes: bool) -> Self
pub fn hide_env(self, yes: bool) -> Self
Do not display in help the environment variable name.
This is useful when the variable option is explained elsewhere in the help text.
Examples
let m = Command::new("prog")
.arg(Arg::new("mode")
.long("mode")
.env("MODE")
.action(ArgAction::Set)
.hide_env(true));If we were to run the above program with --help the [env: MODE] portion of the help
text would be omitted.
Examples found in repository?
7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
fn main() -> Result<(), std::io::Error> {
let cmd = Command::new("myapp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>:Ola Nordmann <old@nordmann.no>")
.about("Does awesome things")
.long_about(
"With a longer description to help clarify some things.
And a few newlines.",
)
.after_help("This is an extra section added to the end of the manpage.")
.after_long_help("With even more text added.")
.arg(
arg!(-c --config <FILE> "Sets a custom config file")
.long_help("Some more text about how to set a custom config file")
.default_value("config.toml")
.env("CONFIG_FILE"),
)
.arg(arg!([output] "Sets an output file").default_value("result.txt"))
.arg(
arg!(-d --debug ... "Turn debugging information on")
.env("DEBUG_ON")
.hide_env(true),
)
.subcommand(
Command::new("test")
.about("does testing things")
.arg(arg!(-l --list "Lists test values")),
);
Man::new(cmd).render(&mut io::stdout())
}sourcepub fn hide_env_values(self, yes: bool) -> Self
pub fn hide_env_values(self, yes: bool) -> Self
Do not display in help any values inside the associated ENV variables for the argument.
This is useful when ENV vars contain sensitive values.
Examples
let m = Command::new("connect")
.arg(Arg::new("host")
.long("host")
.env("CONNECT")
.action(ArgAction::Set)
.hide_env_values(true));
If we were to run the above program with $ CONNECT=super_secret connect --help the
[default: CONNECT=super_secret] portion of the help text would be omitted.
sourcepub fn hide_short_help(self, yes: bool) -> Self
pub fn hide_short_help(self, yes: bool) -> Self
Hides an argument from short help (-h).
NOTE: This does not hide the argument from usage strings on error
NOTE: Setting this option will cause next-line-help output style to be used
when long help (--help) is called.
Examples
Arg::new("debug")
.hide_short_help(true);Setting hide_short_help(true) will hide the argument when displaying short help text
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.hide_short_help(true)
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "-h"
]);The above example displays
helptest
Usage: helptest [OPTIONS]
Options:
-h, --help Print help information
-V, --version Print version informationHowever, when –help is called
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.hide_short_help(true)
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "--help"
]);Then the following would be displayed
helptest
Usage: helptest [OPTIONS]
Options:
--config Some help text describing the --config arg
-h, --help Print help information
-V, --version Print version informationsourcepub fn hide_long_help(self, yes: bool) -> Self
pub fn hide_long_help(self, yes: bool) -> Self
Hides an argument from long help (--help).
NOTE: This does not hide the argument from usage strings on error
NOTE: Setting this option will cause next-line-help output style to be used
when long help (--help) is called.
Examples
Setting hide_long_help(true) will hide the argument when displaying long help text
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.hide_long_help(true)
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "--help"
]);The above example displays
helptest
Usage: helptest [OPTIONS]
Options:
-h, --help Print help information
-V, --version Print version informationHowever, when -h is called
let m = Command::new("prog")
.arg(Arg::new("cfg")
.long("config")
.hide_long_help(true)
.help("Some help text describing the --config arg"))
.get_matches_from(vec![
"prog", "-h"
]);Then the following would be displayed
helptest
Usage: helptest [OPTIONS]
OPTIONS:
--config Some help text describing the --config arg
-h, --help Print help information
-V, --version Print version informationsource§impl Arg
impl Arg
sourcepub fn group(self, group_id: impl IntoResettable<Id>) -> Self
pub fn group(self, group_id: impl IntoResettable<Id>) -> Self
The name of the ArgGroup the argument belongs to.
Examples
Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue)
.group("mode")Multiple arguments can be a member of a single group and then the group checked as if it was one of said arguments.
let m = Command::new("prog")
.arg(Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue)
.group("mode"))
.arg(Arg::new("verbose")
.long("verbose")
.action(ArgAction::SetTrue)
.group("mode"))
.get_matches_from(vec![
"prog", "--debug"
]);
assert!(m.contains_id("mode"));sourcepub fn groups(self, group_ids: impl IntoIterator<Item = impl Into<Id>>) -> Self
pub fn groups(self, group_ids: impl IntoIterator<Item = impl Into<Id>>) -> Self
The names of ArgGroup’s the argument belongs to.
Examples
Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue)
.groups(["mode", "verbosity"])Arguments can be members of multiple groups and then the group checked as if it was one of said arguments.
let m = Command::new("prog")
.arg(Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue)
.groups(["mode", "verbosity"]))
.arg(Arg::new("verbose")
.long("verbose")
.action(ArgAction::SetTrue)
.groups(["mode", "verbosity"]))
.get_matches_from(vec![
"prog", "--debug"
]);
assert!(m.contains_id("mode"));
assert!(m.contains_id("verbosity"));sourcepub fn default_value_if(
self,
arg_id: impl Into<Id>,
predicate: impl Into<ArgPredicate>,
default: impl IntoResettable<OsStr>
) -> Self
pub fn default_value_if(
self,
arg_id: impl Into<Id>,
predicate: impl Into<ArgPredicate>,
default: impl IntoResettable<OsStr>
) -> Self
Specifies the value of the argument if arg has been used at runtime.
If default is set to None, default_value will be removed.
NOTE: This setting is perfectly compatible with Arg::default_value but slightly
different. Arg::default_value only takes effect when the user has not provided this arg
at runtime. This setting however only takes effect when the user has not provided a value at
runtime and these other conditions are met as well. If you have set Arg::default_value
and Arg::default_value_if, and the user did not provide this arg at runtime, nor were
the conditions met for Arg::default_value_if, the Arg::default_value will be applied.
NOTE: This implicitly sets Arg::action(ArgAction::Set).
Examples
First we use the default value only if another arg is present at runtime.
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("other")
.long("other")
.default_value_if("flag", ArgPredicate::IsPresent, Some("default")))
.get_matches_from(vec![
"prog", "--flag"
]);
assert_eq!(m.get_one::<String>("other").unwrap(), "default");Next we run the same test, but without providing --flag.
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("other")
.long("other")
.default_value_if("flag", "true", Some("default")))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("other"), None);Now lets only use the default value if --opt contains the value special.
let m = Command::new("prog")
.arg(Arg::new("opt")
.action(ArgAction::Set)
.long("opt"))
.arg(Arg::new("other")
.long("other")
.default_value_if("opt", "special", Some("default")))
.get_matches_from(vec![
"prog", "--opt", "special"
]);
assert_eq!(m.get_one::<String>("other").unwrap(), "default");We can run the same test and provide any value other than special and we won’t get a
default value.
let m = Command::new("prog")
.arg(Arg::new("opt")
.action(ArgAction::Set)
.long("opt"))
.arg(Arg::new("other")
.long("other")
.default_value_if("opt", "special", Some("default")))
.get_matches_from(vec![
"prog", "--opt", "hahaha"
]);
assert_eq!(m.get_one::<String>("other"), None);If we want to unset the default value for an Arg based on the presence or value of some other Arg.
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("other")
.long("other")
.default_value("default")
.default_value_if("flag", "true", None))
.get_matches_from(vec![
"prog", "--flag"
]);
assert_eq!(m.get_one::<String>("other"), None);sourcepub fn default_value_ifs(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<ArgPredicate>, impl IntoResettable<OsStr>)>
) -> Self
pub fn default_value_ifs(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<ArgPredicate>, impl IntoResettable<OsStr>)>
) -> Self
Specifies multiple values and conditions in the same manner as Arg::default_value_if.
The method takes a slice of tuples in the (arg, predicate, default) format.
NOTE: The conditions are stored in order and evaluated in the same order. I.e. the first if multiple conditions are true, the first one found will be applied and the ultimate value.
Examples
First we use the default value only if another arg is present at runtime.
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("opt")
.long("opt")
.action(ArgAction::Set))
.arg(Arg::new("other")
.long("other")
.default_value_ifs([
("flag", "true", Some("default")),
("opt", "channal", Some("chan")),
]))
.get_matches_from(vec![
"prog", "--opt", "channal"
]);
assert_eq!(m.get_one::<String>("other").unwrap(), "chan");Next we run the same test, but without providing --flag.
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("other")
.long("other")
.default_value_ifs([
("flag", "true", Some("default")),
("opt", "channal", Some("chan")),
]))
.get_matches_from(vec![
"prog"
]);
assert_eq!(m.get_one::<String>("other"), None);We can also see that these values are applied in order, and if more than one condition is true, only the first evaluated “wins”
let m = Command::new("prog")
.arg(Arg::new("flag")
.long("flag")
.action(ArgAction::SetTrue))
.arg(Arg::new("opt")
.long("opt")
.action(ArgAction::Set))
.arg(Arg::new("other")
.long("other")
.default_value_ifs([
("flag", ArgPredicate::IsPresent, Some("default")),
("opt", ArgPredicate::Equals("channal".into()), Some("chan")),
]))
.get_matches_from(vec![
"prog", "--opt", "channal", "--flag"
]);
assert_eq!(m.get_one::<String>("other").unwrap(), "default");sourcepub fn required_unless_present(self, arg_id: impl IntoResettable<Id>) -> Self
pub fn required_unless_present(self, arg_id: impl IntoResettable<Id>) -> Self
Set this arg as required as long as the specified argument is not present at runtime.
Pro Tip: Using Arg::required_unless_present implies Arg::required and is therefore not
mandatory to also set.
Examples
Arg::new("config")
.required_unless_present("debug")In the following example, the required argument is not provided,
but it’s not an error because the unless arg has been supplied.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present("dbg")
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug")
.action(ArgAction::SetTrue))
.try_get_matches_from(vec![
"prog", "--debug"
]);
assert!(res.is_ok());Setting Arg::required_unless_present(name) and not supplying name or this arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present("dbg")
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug"))
.try_get_matches_from(vec![
"prog"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);Examples found in repository?
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn required_unless_present_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
pub fn required_unless_present_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
Sets this arg as required unless all of the specified arguments are present at runtime.
In other words, parsing will succeed only if user either
- supplies the
selfarg. - supplies all of the
namesarguments.
NOTE: If you wish for this argument to only be required unless any of these args are
present see Arg::required_unless_present_any
Examples
Arg::new("config")
.required_unless_present_all(["cfg", "dbg"])In the following example, the required argument is not provided, but it’s not an error
because all of the names args have been supplied.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present_all(["dbg", "infile"])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug")
.action(ArgAction::SetTrue))
.arg(Arg::new("infile")
.short('i')
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--debug", "-i", "file"
]);
assert!(res.is_ok());Setting Arg::required_unless_present_all(names) and not supplying
either all of unless args or the self arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present_all(["dbg", "infile"])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug")
.action(ArgAction::SetTrue))
.arg(Arg::new("infile")
.short('i')
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn required_unless_present_any(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
pub fn required_unless_present_any(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
Sets this arg as required unless any of the specified arguments are present at runtime.
In other words, parsing will succeed only if user either
- supplies the
selfarg. - supplies one or more of the
unlessarguments.
NOTE: If you wish for this argument to be required unless all of these args are
present see Arg::required_unless_present_all
Examples
Arg::new("config")
.required_unless_present_any(["cfg", "dbg"])Setting Arg::required_unless_present_any(names) requires that the argument be used at runtime
unless at least one of the args in names are present. In the following example, the
required argument is not provided, but it’s not an error because one the unless args
have been supplied.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present_any(["dbg", "infile"])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug")
.action(ArgAction::SetTrue))
.arg(Arg::new("infile")
.short('i')
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--debug"
]);
assert!(res.is_ok());Setting Arg::required_unless_present_any(names) and not supplying at least one of names
or this arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_unless_present_any(["dbg", "infile"])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("dbg")
.long("debug")
.action(ArgAction::SetTrue))
.arg(Arg::new("infile")
.short('i')
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn required_if_eq(self, arg_id: impl Into<Id>, val: impl Into<OsStr>) -> Self
pub fn required_if_eq(self, arg_id: impl Into<Id>, val: impl Into<OsStr>) -> Self
This argument is required only if the specified arg is present at runtime and its value
equals val.
Examples
Arg::new("config")
.required_if_eq("other_arg", "value")let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.required_if_eq("other", "special")
.long("config"))
.arg(Arg::new("other")
.long("other")
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--other", "not-special"
]);
assert!(res.is_ok()); // We didn't use --other=special, so "cfg" wasn't required
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.required_if_eq("other", "special")
.long("config"))
.arg(Arg::new("other")
.long("other")
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--other", "special"
]);
// We did use --other=special so "cfg" had become required but was missing.
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.required_if_eq("other", "special")
.long("config"))
.arg(Arg::new("other")
.long("other")
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--other", "SPECIAL"
]);
// By default, the comparison is case-sensitive, so "cfg" wasn't required
assert!(res.is_ok());
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.required_if_eq("other", "special")
.long("config"))
.arg(Arg::new("other")
.long("other")
.ignore_case(true)
.action(ArgAction::Set))
.try_get_matches_from(vec![
"prog", "--other", "SPECIAL"
]);
// However, case-insensitive comparisons can be enabled. This typically occurs when using Arg::possible_values().
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn required_if_eq_any(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self
pub fn required_if_eq_any(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self
Specify this argument is required based on multiple conditions.
The conditions are set up in a (arg, val) style tuple. The requirement will only become
valid if one of the specified arg’s value equals its corresponding val.
Examples
Arg::new("config")
.required_if_eq_any([
("extra", "val"),
("option", "spec")
])Setting Arg::required_if_eq_any([(arg, val)]) makes this arg required if any of the args
are used at runtime and it’s corresponding value is equal to val. If the arg’s value is
anything other than val, this argument isn’t required.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_if_eq_any([
("extra", "val"),
("option", "spec")
])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("extra")
.action(ArgAction::Set)
.long("extra"))
.arg(Arg::new("option")
.action(ArgAction::Set)
.long("option"))
.try_get_matches_from(vec![
"prog", "--option", "other"
]);
assert!(res.is_ok()); // We didn't use --option=spec, or --extra=val so "cfg" isn't requiredSetting Arg::required_if_eq_any([(arg, val)]) and having any of the args used with its
value of val but not using this arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_if_eq_any([
("extra", "val"),
("option", "spec")
])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("extra")
.action(ArgAction::Set)
.long("extra"))
.arg(Arg::new("option")
.action(ArgAction::Set)
.long("option"))
.try_get_matches_from(vec![
"prog", "--option", "spec"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn required_if_eq_all(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self
pub fn required_if_eq_all(
self,
ifs: impl IntoIterator<Item = (impl Into<Id>, impl Into<OsStr>)>
) -> Self
Specify this argument is required based on multiple conditions.
The conditions are set up in a (arg, val) style tuple. The requirement will only become
valid if every one of the specified arg’s value equals its corresponding val.
Examples
Arg::new("config")
.required_if_eq_all([
("extra", "val"),
("option", "spec")
])Setting Arg::required_if_eq_all([(arg, val)]) makes this arg required if all of the args
are used at runtime and every value is equal to its corresponding val. If the arg’s value is
anything other than val, this argument isn’t required.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_if_eq_all([
("extra", "val"),
("option", "spec")
])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("extra")
.action(ArgAction::Set)
.long("extra"))
.arg(Arg::new("option")
.action(ArgAction::Set)
.long("option"))
.try_get_matches_from(vec![
"prog", "--option", "spec"
]);
assert!(res.is_ok()); // We didn't use --option=spec --extra=val so "cfg" isn't requiredSetting Arg::required_if_eq_all([(arg, val)]) and having all of the args used with its
value of val but not using this arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.required_if_eq_all([
("extra", "val"),
("option", "spec")
])
.action(ArgAction::Set)
.long("config"))
.arg(Arg::new("extra")
.action(ArgAction::Set)
.long("extra"))
.arg(Arg::new("option")
.action(ArgAction::Set)
.long("option"))
.try_get_matches_from(vec![
"prog", "--extra", "val", "--option", "spec"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn requires_if(
self,
val: impl Into<ArgPredicate>,
arg_id: impl Into<Id>
) -> Self
pub fn requires_if(
self,
val: impl Into<ArgPredicate>,
arg_id: impl Into<Id>
) -> Self
Require another argument if this arg matches the ArgPredicate
This method takes value, another_arg pair. At runtime, clap will check
if this arg (self) matches the ArgPredicate.
If it does, another_arg will be marked as required.
Examples
Arg::new("config")
.requires_if("val", "arg")Setting Arg::requires_if(val, arg) requires that the arg be used at runtime if the
defining argument’s value is equal to val. If the defining argument is anything other than
val, the other argument isn’t required.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires_if("my.cfg", "other")
.long("config"))
.arg(Arg::new("other"))
.try_get_matches_from(vec![
"prog", "--config", "some.cfg"
]);
assert!(res.is_ok()); // We didn't use --config=my.cfg, so other wasn't requiredSetting Arg::requires_if(val, arg) and setting the value to val but not supplying
arg is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires_if("my.cfg", "input")
.long("config"))
.arg(Arg::new("input"))
.try_get_matches_from(vec![
"prog", "--config", "my.cfg"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn requires_ifs(
self,
ifs: impl IntoIterator<Item = (impl Into<ArgPredicate>, impl Into<Id>)>
) -> Self
pub fn requires_ifs(
self,
ifs: impl IntoIterator<Item = (impl Into<ArgPredicate>, impl Into<Id>)>
) -> Self
Allows multiple conditional requirements.
The requirement will only become valid if this arg’s value matches the
ArgPredicate.
Examples
Arg::new("config")
.requires_ifs([
("val", "arg"),
("other_val", "arg2"),
])Setting Arg::requires_ifs(["val", "arg"]) requires that the arg be used at runtime if the
defining argument’s value is equal to val. If the defining argument’s value is anything other
than val, arg isn’t required.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires_ifs([
("special.conf", "opt"),
("other.conf", "other"),
])
.long("config"))
.arg(Arg::new("opt")
.long("option")
.action(ArgAction::Set))
.arg(Arg::new("other"))
.try_get_matches_from(vec![
"prog", "--config", "special.conf"
]);
assert!(res.is_err()); // We used --config=special.conf so --option <val> is required
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);Setting Arg::requires_ifs with ArgPredicate::IsPresent and not supplying all the
arguments is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.requires_ifs([
(ArgPredicate::IsPresent, "input"),
(ArgPredicate::IsPresent, "output"),
])
.long("config"))
.arg(Arg::new("input"))
.arg(Arg::new("output"))
.try_get_matches_from(vec![
"prog", "--config", "file.conf", "in.txt"
]);
assert!(res.is_err());
// We didn't use output
assert_eq!(res.unwrap_err().kind(), ErrorKind::MissingRequiredArgument);sourcepub fn conflicts_with(self, arg_id: impl IntoResettable<Id>) -> Self
pub fn conflicts_with(self, arg_id: impl IntoResettable<Id>) -> Self
This argument is mutually exclusive with the specified argument.
NOTE: Conflicting rules take precedence over being required by default. Conflict rules only need to be set for one of the two arguments, they do not need to be set for each.
NOTE: Defining a conflict is two-way, but does not need to defined for both arguments (i.e. if A conflicts with B, defining A.conflicts_with(B) is sufficient. You do not need to also do B.conflicts_with(A))
NOTE: Arg::conflicts_with_all(names) allows specifying an argument which conflicts with more than one argument.
NOTE Arg::exclusive(true) allows specifying an argument which conflicts with every other argument.
NOTE: All arguments implicitly conflict with themselves.
Examples
Arg::new("config")
.conflicts_with("debug")Setting conflicting argument, and having both arguments present at runtime is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.conflicts_with("debug")
.long("config"))
.arg(Arg::new("debug")
.long("debug")
.action(ArgAction::SetTrue))
.try_get_matches_from(vec![
"prog", "--debug", "--config", "file.conf"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);Examples found in repository?
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111
fn main() {
let matches = Command::new("pacman")
.about("package manager utility")
.version("5.2.1")
.subcommand_required(true)
.arg_required_else_help(true)
.author("Pacman Development Team")
// Query subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("query")
.short_flag('Q')
.long_flag("query")
.about("Query the package database.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.help("search locally installed packages for matching strings")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..),
)
.arg(
Arg::new("info")
.long("info")
.short('i')
.conflicts_with("search")
.help("view package information")
.action(ArgAction::Set)
.num_args(1..),
),
)
// Sync subcommand
//
// Only a few of its arguments are implemented below.
.subcommand(
Command::new("sync")
.short_flag('S')
.long_flag("sync")
.about("Synchronize packages.")
.arg(
Arg::new("search")
.short('s')
.long("search")
.conflicts_with("info")
.action(ArgAction::Set)
.num_args(1..)
.help("search remote repositories for matching strings"),
)
.arg(
Arg::new("info")
.long("info")
.conflicts_with("search")
.short('i')
.action(ArgAction::SetTrue)
.help("view package information"),
)
.arg(
Arg::new("package")
.help("packages")
.required_unless_present("search")
.action(ArgAction::Set)
.num_args(1..),
),
)
.get_matches();
match matches.subcommand() {
Some(("sync", sync_matches)) => {
if sync_matches.contains_id("search") {
let packages: Vec<_> = sync_matches
.get_many::<String>("search")
.expect("contains_id")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
println!("Searching for {}...", values);
return;
}
let packages: Vec<_> = sync_matches
.get_many::<String>("package")
.expect("is present")
.map(|s| s.as_str())
.collect();
let values = packages.join(", ");
if sync_matches.get_flag("info") {
println!("Retrieving info for {}...", values);
} else {
println!("Installing {}...", values);
}
}
Some(("query", query_matches)) => {
if let Some(packages) = query_matches.get_many::<String>("info") {
let comma_sep = packages.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Retrieving info for {}...", comma_sep);
} else if let Some(queries) = query_matches.get_many::<String>("search") {
let comma_sep = queries.map(|s| s.as_str()).collect::<Vec<_>>().join(", ");
println!("Searching Locally for {}...", comma_sep);
} else {
println!("Displaying all locally installed packages...");
}
}
_ => unreachable!(), // If all subcommands are defined above, anything else is unreachable
}
}sourcepub fn conflicts_with_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
pub fn conflicts_with_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
This argument is mutually exclusive with the specified arguments.
See Arg::conflicts_with.
NOTE: Conflicting rules take precedence over being required by default. Conflict rules only need to be set for one of the two arguments, they do not need to be set for each.
NOTE: Defining a conflict is two-way, but does not need to defined for both arguments (i.e. if A conflicts with B, defining A.conflicts_with(B) is sufficient. You do not need need to also do B.conflicts_with(A))
NOTE: Arg::exclusive(true) allows specifying an argument which conflicts with every other argument.
Examples
Arg::new("config")
.conflicts_with_all(["debug", "input"])Setting conflicting argument, and having any of the arguments present at runtime with a conflicting argument is an error.
let res = Command::new("prog")
.arg(Arg::new("cfg")
.action(ArgAction::Set)
.conflicts_with_all(["debug", "input"])
.long("config"))
.arg(Arg::new("debug")
.long("debug"))
.arg(Arg::new("input"))
.try_get_matches_from(vec![
"prog", "--config", "file.conf", "file.txt"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind(), ErrorKind::ArgumentConflict);sourcepub fn overrides_with(self, arg_id: impl IntoResettable<Id>) -> Self
pub fn overrides_with(self, arg_id: impl IntoResettable<Id>) -> Self
Sets an overridable argument.
i.e. this argument and the following argument will override each other in POSIX style (whichever argument was specified at runtime last “wins”)
NOTE: When an argument is overridden it is essentially as if it never was used, any conflicts, requirements, etc. are evaluated after all “overrides” have been removed
NOTE: Overriding an argument implies they conflict.
Examples
let m = Command::new("prog")
.arg(arg!(-f --flag "some flag")
.conflicts_with("debug"))
.arg(arg!(-d --debug "other flag"))
.arg(arg!(-c --color "third flag")
.overrides_with("flag"))
.get_matches_from(vec![
"prog", "-f", "-d", "-c"]);
// ^~~~~~~~~~~~^~~~~ flag is overridden by color
assert!(*m.get_one::<bool>("color").unwrap());
assert!(*m.get_one::<bool>("debug").unwrap()); // even though flag conflicts with debug, it's as if flag
// was never used because it was overridden with color
assert!(!*m.get_one::<bool>("flag").unwrap());sourcepub fn overrides_with_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
pub fn overrides_with_all(
self,
names: impl IntoIterator<Item = impl Into<Id>>
) -> Self
Sets multiple mutually overridable arguments by name.
i.e. this argument and the following argument will override each other in POSIX style (whichever argument was specified at runtime last “wins”)
NOTE: When an argument is overridden it is essentially as if it never was used, any conflicts, requirements, etc. are evaluated after all “overrides” have been removed
NOTE: Overriding an argument implies they conflict.
Examples
let m = Command::new("prog")
.arg(arg!(-f --flag "some flag")
.conflicts_with("color"))
.arg(arg!(-d --debug "other flag"))
.arg(arg!(-c --color "third flag")
.overrides_with_all(["flag", "debug"]))
.get_matches_from(vec![
"prog", "-f", "-d", "-c"]);
// ^~~~~~^~~~~~~~~ flag and debug are overridden by color
assert!(*m.get_one::<bool>("color").unwrap()); // even though flag conflicts with color, it's as if flag
// and debug were never used because they were overridden
// with color
assert!(!*m.get_one::<bool>("debug").unwrap());
assert!(!*m.get_one::<bool>("flag").unwrap());source§impl Arg
impl Arg
sourcepub fn get_long_help(&self) -> Option<&StyledStr>
pub fn get_long_help(&self) -> Option<&StyledStr>
Get the long help specified for this argument, if any
Examples
let arg = Arg::new("foo").long_help("long help");
assert_eq!(Some("long help".to_owned()), arg.get_long_help().map(|s| s.to_string()));sourcepub fn get_help_heading(&self) -> Option<&str>
pub fn get_help_heading(&self) -> Option<&str>
Get the help heading specified for this argument, if any
sourcepub fn get_visible_short_aliases(&self) -> Option<Vec<char>>
pub fn get_visible_short_aliases(&self) -> Option<Vec<char>>
Get visible short aliases for this argument, if any
sourcepub fn get_all_short_aliases(&self) -> Option<Vec<char>>
pub fn get_all_short_aliases(&self) -> Option<Vec<char>>
Get all short aliases for this argument, if any, both visible and hidden.
sourcepub fn get_short_and_visible_aliases(&self) -> Option<Vec<char>>
pub fn get_short_and_visible_aliases(&self) -> Option<Vec<char>>
Get the short option name and its visible aliases, if any
sourcepub fn get_visible_aliases(&self) -> Option<Vec<&str>>
pub fn get_visible_aliases(&self) -> Option<Vec<&str>>
Get visible aliases for this argument, if any
sourcepub fn get_all_aliases(&self) -> Option<Vec<&str>>
pub fn get_all_aliases(&self) -> Option<Vec<&str>>
Get all aliases for this argument, if any, both visible and hidden.
sourcepub fn get_long_and_visible_aliases(&self) -> Option<Vec<&str>>
pub fn get_long_and_visible_aliases(&self) -> Option<Vec<&str>>
Get the long option name and its visible aliases, if any
sourcepub fn get_possible_values(&self) -> Vec<PossibleValue>
pub fn get_possible_values(&self) -> Vec<PossibleValue>
Get the names of possible values for this argument. Only useful for user facing applications, such as building help messages or man files
sourcepub fn get_value_names(&self) -> Option<&[Str]>
pub fn get_value_names(&self) -> Option<&[Str]>
Get the names of values for this argument.
sourcepub fn get_num_args(&self) -> Option<ValueRange>
pub fn get_num_args(&self) -> Option<ValueRange>
Get the number of values for this argument.
sourcepub fn get_value_delimiter(&self) -> Option<char>
pub fn get_value_delimiter(&self) -> Option<char>
Get the delimiter between multiple values
sourcepub fn get_value_hint(&self) -> ValueHint
pub fn get_value_hint(&self) -> ValueHint
Get the value hint of this argument
sourcepub fn get_env(&self) -> Option<&OsStr>
pub fn get_env(&self) -> Option<&OsStr>
Get the environment variable name specified for this argument, if any
Examples
let arg = Arg::new("foo").env("ENVIRONMENT");
assert_eq!(arg.get_env(), Some(OsStr::new("ENVIRONMENT")));sourcepub fn get_default_values(&self) -> &[OsStr]
pub fn get_default_values(&self) -> &[OsStr]
Get the default values specified for this argument, if any
Examples
let arg = Arg::new("foo").default_value("default value");
assert_eq!(arg.get_default_values(), &["default value"]);sourcepub fn is_positional(&self) -> bool
pub fn is_positional(&self) -> bool
Checks whether this argument is a positional or not.
Examples
let arg = Arg::new("foo");
assert_eq!(arg.is_positional(), true);
let arg = Arg::new("foo").long("foo");
assert_eq!(arg.is_positional(), false);sourcepub fn is_required_set(&self) -> bool
pub fn is_required_set(&self) -> bool
Reports whether Arg::required is set
sourcepub fn is_allow_hyphen_values_set(&self) -> bool
pub fn is_allow_hyphen_values_set(&self) -> bool
Report whether Arg::allow_hyphen_values is set
sourcepub fn is_allow_negative_numbers_set(&self) -> bool
pub fn is_allow_negative_numbers_set(&self) -> bool
Report whether Arg::allow_negative_numbers is set
sourcepub fn get_action(&self) -> &ArgAction
pub fn get_action(&self) -> &ArgAction
Behavior when parsing the argument
sourcepub fn get_value_parser(&self) -> &ValueParser
pub fn get_value_parser(&self) -> &ValueParser
Configured parser for argument values
Example
let cmd = clap::Command::new("raw")
.arg(
clap::Arg::new("port")
.value_parser(clap::value_parser!(usize))
);
let value_parser = cmd.get_arguments()
.find(|a| a.get_id() == "port").unwrap()
.get_value_parser();
println!("{:?}", value_parser);sourcepub fn is_global_set(&self) -> bool
pub fn is_global_set(&self) -> bool
Report whether Arg::global is set
sourcepub fn is_next_line_help_set(&self) -> bool
pub fn is_next_line_help_set(&self) -> bool
Report whether Arg::next_line_help is set
sourcepub fn is_hide_set(&self) -> bool
pub fn is_hide_set(&self) -> bool
Report whether Arg::hide is set
sourcepub fn is_hide_default_value_set(&self) -> bool
pub fn is_hide_default_value_set(&self) -> bool
Report whether Arg::hide_default_value is set
sourcepub fn is_hide_possible_values_set(&self) -> bool
pub fn is_hide_possible_values_set(&self) -> bool
Report whether Arg::hide_possible_values is set
sourcepub fn is_hide_env_set(&self) -> bool
pub fn is_hide_env_set(&self) -> bool
Report whether Arg::hide_env is set
sourcepub fn is_hide_env_values_set(&self) -> bool
pub fn is_hide_env_values_set(&self) -> bool
Report whether Arg::hide_env_values is set
sourcepub fn is_hide_short_help_set(&self) -> bool
pub fn is_hide_short_help_set(&self) -> bool
Report whether Arg::hide_short_help is set
sourcepub fn is_hide_long_help_set(&self) -> bool
pub fn is_hide_long_help_set(&self) -> bool
Report whether Arg::hide_long_help is set
sourcepub fn is_require_equals_set(&self) -> bool
pub fn is_require_equals_set(&self) -> bool
Report whether Arg::require_equals is set
sourcepub fn is_exclusive_set(&self) -> bool
pub fn is_exclusive_set(&self) -> bool
Reports whether Arg::exclusive is set
sourcepub fn is_trailing_var_arg_set(&self) -> bool
pub fn is_trailing_var_arg_set(&self) -> bool
Report whether Arg::trailing_var_arg is set
sourcepub fn is_last_set(&self) -> bool
pub fn is_last_set(&self) -> bool
Reports whether Arg::last is set
sourcepub fn is_ignore_case_set(&self) -> bool
pub fn is_ignore_case_set(&self) -> bool
Reports whether Arg::ignore_case is set
Trait Implementations§
source§impl Ord for Arg
impl Ord for Arg
source§impl PartialOrd<Arg> for Arg
impl PartialOrd<Arg> for Arg
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self and other) and is used by the <=
operator. Read more