clap/examples/06_positional_args.rs
Ed Page 93948cc724 docs(examples): Work around non-commutative conflicts
The comments in these examples say that a `conflicts_with` should
override `required`.  This seems to be true one way but not the other,
causing these examples to error out at runtime.
2021-11-17 15:23:31 -06:00

49 lines
2.2 KiB
Rust

use clap::{App, Arg};
fn main() {
// Positional arguments are those values after the program name which are not preceded by any
// identifier (such as "myapp some_file"). Positionals support many of the same options as
// flags, as well as a few additional ones.
let matches = App::new("MyApp")
// Regular App configuration goes here...
// We'll add two positional arguments, an input file, and a config file.
//
// I'll explain each possible setting that "positionals" accept. Keep in
// mind that you DO NOT need to set each of these for every flag, only the
// ones that apply to your individual case.
.arg(
Arg::new("input")
.about("the input file to use") // Displayed when showing help info
.index(1) // Set the order in which the user must
// specify this argument (Starts at 1)
.requires("config") // Says, "If the user uses "input", they MUST
// also use this other 'config' arg too"
// Can also specify a list using
// requires_all(Vec<&str>)
.required(true), // By default this argument MUST be present
// NOTE: mutual exclusions take precedence over
// required arguments
)
.arg(Arg::new("config").about("the config file to use").index(2)) // Note, we do not need to specify required(true)
// if we don't want to, because "input" already
// requires "config"
// Note, we also do not need to specify requires("input")
// because requires lists are automatically two-way
.get_matches();
// We can find out whether or not "input" or "config" were used
if matches.is_present("input") {
println!("An input file was specified");
}
// We can also get the values for those arguments
if let Some(ref in_file) = matches.value_of("input") {
// It's safe to call unwrap() because of the required options we set above
println!(
"Doing work with {} and {}",
in_file,
matches.value_of("config").unwrap()
);
}
// Continued program logic goes here...
}