basic/
basic.rs

1use just_getopt::{OptFlags, OptSpecs, OptValueType};
2use std::process::ExitCode;
3
4fn main() -> ExitCode {
5    // The `OptSpecs::new()` function below creates a new option
6    // specification struct `OptSpecs`. Its `option()` methods configure
7    // three different options for logical meanings "help", "file" and
8    // "verbose". All three options can be written in command-line with
9    // a short variant (like "-h") and a long variant (like "--help").
10    // Some options accept or require a value.
11    //
12    // Flag OptionsEverywhere changes parser's behavior. This flag means
13    // that options and other arguments (non-options) can be mixed in
14    // their order in the command line. Without the flag the option
15    // parsing stops at the first non-option argument and the rest of
16    // the command-line is parsed as non-options.
17    let specs = OptSpecs::new()
18        .flag(OptFlags::OptionsEverywhere) // Argument: (flag)
19        .option("help", "h", OptValueType::None) // Arguments: (id, name, value_type)
20        .option("help", "help", OptValueType::None)
21        .option("file", "f", OptValueType::Required)
22        .option("file", "file", OptValueType::Required)
23        .option("verbose", "v", OptValueType::Optional)
24        .option("verbose", "verbose", OptValueType::Optional);
25
26    // Get arguments iterator from operating system and skip the first item
27    let args = std::env::args().skip(1); // which is this program's file path.
28
29    // Parse program's command-line with the given specification `specs`.
30    let parsed = specs.getopt(args);
31
32    // With this you can see the parsed output which is an `Args`
33    // struct.
34    eprintln!("{:#?}", parsed);
35
36    // Report user about unknown options.
37    for u in &parsed.unknown {
38        eprintln!("Unknown option: {}", u);
39    }
40
41    // Report user about missing values for options that require them
42    // (i.e. "file"). Exit the program with error code.
43    for o in &parsed.required_value_missing() {
44        eprintln!("Value is required for option '{}'.", o.name);
45        return ExitCode::FAILURE;
46    }
47
48    // Print help and exit because "-h" or "--help" was given. We use
49    // option's identifier string "help" here to find if the correct
50    // option was present in the command line. See the `id` argument of
51    // `option()` methods above.
52    if parsed.option_exists("help") {
53        println!("Print friendly help about program's usage.");
54        return ExitCode::from(2);
55    }
56
57    // Collect all (required) values for "-f" and "--file". We use
58    // option's identifier (id) string "file" to find the option.
59    for f in &parsed.options_value_all("file") {
60        println!("File name: {:?}", f);
61    }
62
63    // Notice if "-v" or "--verbose" was given (even without a value).
64    // Then collect all its (optional) values. We use option's
65    // identifier (id) string "verbose".
66    if parsed.option_exists("verbose") {
67        println!("Option 'verbose' was given.");
68
69        for v in &parsed.options_value_all("verbose") {
70            println!("Verbose level: {:?}", v);
71        }
72    }
73
74    // Collect all other (non-option) arguments.
75    for o in &parsed.other {
76        println!("Other argument: {:?}", o);
77    }
78
79    // Try to run this program with various command-line options to see
80    // the output.
81    ExitCode::SUCCESS
82}
basic/basic.rs

basic/
basic.rs
