Enum Flag

Source

pub enum Flag {
    Long {
        spec: FlagSpec,
        index: usize,
    },
    Short {
        spec: FlagSpec,
        index: usize,
    },
    Env {
        spec: FlagSpec,
    },
    None {
        spec: FlagSpec,
    },
}

Expand description

A named argument without value.

Variants§

§

Long

Fields

§spec: FlagSpec

§index: usize

§

Short

Fields

§spec: FlagSpec

§index: usize

§

Env

Fields

§spec: FlagSpec

§

None

Fields

§spec: FlagSpec

Implementations§

Source §

impl Flag

Source

pub fn spec(self) -> FlagSpec

Returns the specification of this flag.

Source

pub fn is_present(self) -> bool

Returns true if this flag is set.

Examples found in repository ?

examples/subcommands.rs (line 6)

1fn main() -> noargs::Result<()> {
2    let mut args = noargs::raw_args();
3    args.metadata_mut().app_name = env!("CARGO_PKG_NAME");
4    args.metadata_mut().app_description = env!("CARGO_PKG_DESCRIPTION");
5
6    if noargs::VERSION_FLAG.take(&mut args).is_present() {
7        println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
8        return Ok(());
9    }
10    noargs::HELP_FLAG.take_help(&mut args);
11
12    // In real applications, split each `try_run_*` command into separate modules/files.
13    let _ = try_run_hello(&mut args)? || try_run_sum(&mut args)? || try_run_echo(&mut args)?;
14
15    if let Some(help) = args.finish()? {
16        print!("{help}");
17    }
18
19    Ok(())
20}
21
22fn try_run_hello(args: &mut noargs::RawArgs) -> noargs::Result<bool> {
23    if !noargs::cmd("hello")
24        .doc("Print a greeting")
25        .take(args)
26        .is_present()
27    {
28        return Ok(false);
29    }
30
31    let loud = noargs::flag("loud")
32        .short('l')
33        .doc("Print greeting in upper case")
34        .take(args)
35        .is_present();
36    let name: String = noargs::arg("<NAME>")
37        .doc("Name to greet")
38        .example("Alice")
39        .take(args)
40        .then(|a| a.value().parse())?;
41
42    if args.metadata().help_mode {
43        return Ok(true);
44    }
45
46    let message = format!("Hello, {name}!");
47    if loud {
48        println!("{}", message.to_uppercase());
49    } else {
50        println!("{message}");
51    }
52    Ok(true)
53}
54
55fn try_run_sum(args: &mut noargs::RawArgs) -> noargs::Result<bool> {
56    if !noargs::cmd("sum")
57        .doc("Add two integers")
58        .take(args)
59        .is_present()
60    {
61        return Ok(false);
62    }
63
64    let repeat: usize = noargs::opt("repeat")
65        .short('r')
66        .ty("N")
67        .doc("Print result multiple times")
68        .default("1")
69        .take(args)
70        .then(|o| o.value().parse())?;
71    let left: i64 = noargs::arg("<LEFT>")
72        .doc("Left operand")
73        .example("3")
74        .take(args)
75        .then(|a| a.value().parse())?;
76    let right: i64 = noargs::arg("<RIGHT>")
77        .doc("Right operand")
78        .example("4")
79        .take(args)
80        .then(|a| a.value().parse())?;
81
82    if args.metadata().help_mode {
83        return Ok(true);
84    }
85
86    let total = left + right;
87    for _ in 0..repeat {
88        println!("{total}");
89    }
90    Ok(true)
91}
92
93fn try_run_echo(args: &mut noargs::RawArgs) -> noargs::Result<bool> {
94    if !noargs::cmd("echo")
95        .doc("Print a message")
96        .take(args)
97        .is_present()
98    {
99        return Ok(false);
100    }
101
102    let upper = noargs::flag("upper")
103        .short('u')
104        .doc("Uppercase the message")
105        .take(args)
106        .is_present();
107    let text: String = noargs::arg("<TEXT>")
108        .doc("Message text")
109        .example("hello world")
110        .take(args)
111        .then(|a| a.value().parse())?;
112
113    if args.metadata().help_mode {
114        return Ok(true);
115    }
116
117    if upper {
118        println!("{}", text.to_uppercase());
119    } else {
120        println!("{text}");
121    }
122    Ok(true)
123}

More examples

Hide additional examples

examples/arrays.rs (line 6)

1fn main() -> noargs::Result<()> {
2    let mut args = noargs::raw_args();
3    args.metadata_mut().app_name = env!("CARGO_PKG_NAME");
4    args.metadata_mut().app_description = env!("CARGO_PKG_DESCRIPTION");
5
6    if noargs::VERSION_FLAG.take(&mut args).is_present() {
7        println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
8        return Ok(());
9    }
10    noargs::HELP_FLAG.take_help(&mut args);
11
12    // Same-name options can be collected by calling take() in a loop.
13    let include_opt = noargs::opt("include")
14        .short('I')
15        .ty("PATH")
16        .doc("Include path (can be specified multiple times)");
17    let mut includes = Vec::<String>::new();
18    while let Some(path) = include_opt
19        .take(&mut args)
20        .present_and_then(|o| o.value().parse())?
21    {
22        includes.push(path);
23    }
24
25    let label_opt = noargs::opt("label")
26        .short('l')
27        .ty("LABEL")
28        .doc("Label value (can be specified multiple times)");
29    let mut labels = Vec::<String>::new();
30    while let Some(label) = label_opt
31        .take(&mut args)
32        .present_and_then(|o| o.value().parse())?
33    {
34        labels.push(label);
35    }
36
37    let output: String = noargs::opt("output")
38        .short('o')
39        .ty("PATH")
40        .doc("Output path")
41        .default("summary.txt")
42        .take(&mut args)
43        .then(|o| o.value().parse())?;
44
45    // Positional arrays are handled with one required argument + optional rest.
46    // Naming convention: use `<NAME>...` for required-many and `[NAME]...` for optional-many.
47    // The `<>` / `[]` / `...` markers are cosmetic (used only in help output);
48    // required-ness is enforced below: `.then()` makes the first input required,
49    // the loop with `.present_and_then()` consumes zero or more rest inputs.
50    let first_input: String = noargs::arg("<INPUT>")
51        .doc("First input (required)")
52        .example("a.txt")
53        .take(&mut args)
54        .then(|a| a.value().parse())?;
55    let rest_input_arg = noargs::arg("[INPUT]...").doc("Additional inputs");
56    let mut inputs = vec![first_input];
57    while let Some(input) = rest_input_arg
58        .take(&mut args)
59        .present_and_then(|a| a.value().parse())?
60    {
61        inputs.push(input);
62    }
63
64    if let Some(help) = args.finish()? {
65        print!("{help}");
66        return Ok(());
67    }
68
69    println!("includes={includes:?}");
70    println!("labels={labels:?}");
71    println!("inputs={inputs:?}");
72    println!("output={output}");
73    Ok(())
74}

examples/basics.rs (line 6)

1fn main() -> noargs::Result<()> {
2    let mut args = noargs::raw_args();
3    args.metadata_mut().app_name = env!("CARGO_PKG_NAME");
4    args.metadata_mut().app_description = env!("CARGO_PKG_DESCRIPTION");
5
6    if noargs::VERSION_FLAG.take(&mut args).is_present() {
7        println!("{} {}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
8        return Ok(());
9    }
10    noargs::HELP_FLAG.take_help(&mut args);
11
12    // Important: call flag()/opt() before arg().
13    // Otherwise values like "-v" — or any unknown "--bogus" — can be silently
14    // consumed as positional arguments.
15    //
16    // Required option / positional: set example("...") so help mode renders
17    // a meaningful Usage / Example line. Optional fields covered by default()
18    // or present_and_then() do not need example().
19    let verbose = noargs::flag("verbose")
20        .short('v')
21        .doc("Enable verbose output")
22        .take(&mut args)
23        .is_present();
24    let dry_run = noargs::flag("dry-run")
25        .doc("Print parsed values and exit without running processing")
26        .take(&mut args)
27        .is_present();
28    let retries: usize = noargs::opt("retries")
29        .short('r')
30        .ty("N")
31        .doc("How many times to retry")
32        .default("1")
33        .take(&mut args)
34        .then(|o| o.value().parse())?;
35    let endpoint: String = noargs::opt("endpoint")
36        .ty("URL")
37        .doc("Server endpoint")
38        .env("NOARGS_ENDPOINT")
39        .default("http://localhost:8080")
40        .take(&mut args)
41        .then(|o| o.value().parse())?;
42    let format: String = noargs::opt("format")
43        .ty("FORMAT")
44        .doc("Output format")
45        .example("json")
46        .take(&mut args)
47        .then(|o| o.value().parse())?;
48    let timeout_secs: Option<u64> = noargs::opt("timeout")
49        .ty("SECONDS")
50        .doc("Optional timeout in seconds")
51        .take(&mut args)
52        .present_and_then(|o| o.value().parse())?;
53
54    let input: String = noargs::arg("<INPUT>")
55        .doc("Input file path")
56        .example("input.txt")
57        .take(&mut args)
58        .then(|a| a.value().parse())?;
59    // Optional positional with default(): the value is always a String —
60    // absent uses "out.txt", present uses the given path.
61    // For "absent vs present" distinction, use present_and_then() and bind
62    // to Option<String> — see the README's [BAZ] example.
63    let output: String = noargs::arg("[OUTPUT]")
64        .doc("Output file path")
65        .default("out.txt")
66        .take(&mut args)
67        .then(|a| a.value().parse())?;
68
69    if let Some(help) = args.finish()? {
70        // When help is requested, finish() returns the built help text.
71        // Print it here and exit without running application logic.
72        print!("{help}");
73        return Ok(());
74    }
75
76    if dry_run {
77        println!(
78            "dry-run: verbose={verbose}, retries={retries}, endpoint={endpoint}, format={format}, timeout_secs={timeout_secs:?}, input={input}, output={output}"
79        );
80        return Ok(());
81    }
82
83    println!("processing: {input} -> {output}");
84    println!("using endpoint={endpoint}, format={format}, retries={retries}");
85    if verbose {
86        println!("verbose: timeout_secs={timeout_secs:?}");
87    }
88
89    Ok(())
90}