basic/
basic.rs

1// In normal Rust development environment you can run this example code
2// with commmands like
3//     cargo run --example basic -- -abc --foo
4//     cargo run --example basic -- -f 123 --file=456 foo -v3 bar
5
6use just_getopt::{OptFlags, OptSpecs, OptValue};
7
8fn main() {
9    // The `OptSpecs::new()` function below creates a new option
10    // specification struct `OptSpecs`. Its `option()` methods configure
11    // three different options for logical meanings "help", "file" and
12    // "verbose". All three options can be written in command-line with
13    // a short variant (like "-h") and a long variant (like "--help").
14    // Some options accept or require a value.
15    //
16    // Flag OptionsEverywhere changes parser's behavior. This flag means
17    // that options and other arguments (non-options) can be mixed in
18    // their order in the command line. Without the flag the option
19    // parsing stops at the first non-option argument and the rest of
20    // the command-line is parsed as non-options.
21    let specs = OptSpecs::new()
22        .option("help", "h", OptValue::None) // Arguments: (id, name, value_type)
23        .option("help", "help", OptValue::None)
24        .option("file", "f", OptValue::RequiredNonEmpty)
25        .option("file", "file", OptValue::RequiredNonEmpty)
26        .option("verbose", "v", OptValue::OptionalNonEmpty)
27        .option("verbose", "verbose", OptValue::OptionalNonEmpty)
28        .flag(OptFlags::OptionsEverywhere);
29
30    // Get arguments iterator from operating system and skip the first item
31    let args = std::env::args().skip(1); // which is this program's file path.
32
33    // Parse program's command-line with the given specification `specs`.
34    let parsed = specs.getopt(args);
35
36    // With this you can see the parsed output which is an `Args`
37    // struct.
38    eprintln!("{:#?}", parsed);
39
40    // Create a condition variable for possible exit on error.
41    let mut error_exit = false;
42
43    // Report user about unknown options.
44    for u in &parsed.unknown {
45        eprintln!("Unknown option: {u}");
46        error_exit = true;
47    }
48
49    // Report user about missing values for options that require them
50    // (i.e. "file").
51    for o in parsed.required_value_missing() {
52        eprintln!("Value is required for option '{}'.", o.name);
53        error_exit = true;
54    }
55
56    // Exit if there were bad command-line arguments.
57    if error_exit {
58        eprintln!("Use '-h' for help.");
59        std::process::exit(1);
60    }
61
62    // Print help and exit because "-h" or "--help" was given. We use
63    // option's identifier string "help" here to find if the correct
64    // option was present in the command line. See the `id` argument of
65    // `option()` methods above.
66    if parsed.option_exists("help") {
67        println!("Print friendly help about program's usage.");
68        std::process::exit(0);
69    }
70
71    // Collect all (required) values for "-f" and "--file". We use
72    // option's identifier (id) string "file" to find the option.
73    for f in parsed.options_value_all("file") {
74        println!("File name: {:?}", f);
75    }
76
77    // Notice if "-v" or "--verbose" was given (even without a value).
78    // Then collect all its (optional) values. We use option's
79    // identifier (id) string "verbose".
80    if parsed.option_exists("verbose") {
81        println!("Option 'verbose' was given.");
82        for v in parsed.options_value_all("verbose") {
83            println!("Verbose level: {:?}", v);
84        }
85    }
86
87    // Collect all other (non-option) arguments.
88    for o in &parsed.other {
89        println!("Other argument: {:?}", o);
90    }
91}
basic/basic.rs

basic/
basic.rs
