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Diffstat (limited to 'clap/examples/05_flag_args.rs')
| -rw-r--r-- | clap/examples/05_flag_args.rs | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/clap/examples/05_flag_args.rs b/clap/examples/05_flag_args.rs new file mode 100644 index 0000000..a6b8945 --- /dev/null +++ b/clap/examples/05_flag_args.rs @@ -0,0 +1,56 @@ +extern crate clap; + +use clap::{App, Arg}; + +fn main() { + + // Of the three argument types, flags are the most simple. Flags are simple switches which can + // be either "on" or "off" + // + // clap also supports multiple occurrences of flags, the common example is "verbosity" where a + // user could want a little information with "-v" or tons of information with "-v -v" or "-vv" + let matches = App::new("MyApp") + // Regular App configuration goes here... + + // We'll add a flag that represents an awesome meter... + // + // I'll explain each possible setting that "flags" accept. Keep in mind + // that you DO NOT need to set each of these for every flag, only the ones + // you want for your individual case. + .arg(Arg::with_name("awesome") + .help("turns up the awesome") // Displayed when showing help info + .short("a") // Trigger this arg with "-a" + .long("awesome") // Trigger this arg with "--awesome" + .multiple(true) // This flag should allow multiple + // occurrences such as "-aaa" or "-a -a" + .requires("config") // Says, "If the user uses -a, they MUST + // also use this other 'config' arg too" + // Can also specify a list using + // requires_all(Vec<&str>) + .conflicts_with("output") // Opposite of requires(), says "if the + // user uses -a, they CANNOT use 'output'" + // also has a conflicts_with_all(Vec<&str>) + ) + // NOTE: In order to compile this example, comment out requires() and + // conflicts_with() because we have not defined an "output" or "config" + // argument. + .get_matches(); + + // We can find out whether or not awesome was used + if matches.is_present("awesome") { + println!("Awesomeness is turned on"); + } + + // If we set the multiple() option of a flag we can check how many times the user specified + // + // Note: if we did not specify the multiple() option, and the user used "awesome" we would get + // a 1 (no matter how many times they actually used it), or a 0 if they didn't use it at all + match matches.occurrences_of("awesome") { + 0 => println!("Nothing is awesome"), + 1 => println!("Some things are awesome"), + 2 => println!("Lots of things are awesome"), + 3 | _ => println!("EVERYTHING is awesome!"), + } + + // Continued program logic goes here... +} |