1
2
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
|
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...
}
|
