clap/examples/08_subcommands.rs
2018-11-14 12:05:06 -05:00

59 lines
2.5 KiB
Rust

extern crate clap;
use clap::{App, Arg};
fn main() {
// s function exactly like sub-Apps, because that's exactly what they are. Each
// instance of a can have it's own version, author(s), Args, and even it's own
// subcommands.
//
// # Help and Version
// Just like Apps, each subcommand will get it's own "help" and "version" flags automatically
// generated. Also, like Apps, you can override "-V" or "-h" safely and still get "--help" and
// "--version" auto generated.
//
// NOTE: If you specify a subcommand for your App, clap will also autogenerate a "help"
// subcommand along with "-h" and "--help" (applies to sub-subcommands as well).
//
// Just like arg() and args(), subcommands can be specified one at a time via subcommand() or
// multiple ones at once with a Vec<> provided to subcommands().
let matches = App::new("MyApp")
// Normal App and Arg configuration goes here...
// In the following example assume we wanted an application which
// supported an "add" subcommand, this "add" subcommand also took
// one positional argument of a file to add:
.subcommand(
App::new("add") // The name we call argument with
.about("Adds files to myapp") // The message displayed in "myapp -h"
// or "myapp help"
.version("0.1") // Subcommands can have independent version
.author("Kevin K.") // And authors
.arg(
Arg::with_name("input") // And their own arguments
.help("the file to add")
.index(1)
.required(true),
),
)
.get_matches();
// You can check if a subcommand was used like normal
if matches.is_present("add") {
println!("'myapp add' was run.");
}
// You can get the independent subcommand matches (which function exactly like App matches)
if let Some(ref matches) = matches.subcommand_matches("add") {
// Safe to use unwrap() because of the required() option
println!("Adding file: {}", matches.value_of("input").unwrap());
}
// You can also match on a subcommand's name
match matches.subcommand_name() {
Some("add") => println!("'myapp add' was used"),
None => println!("No subcommand was used"),
_ => println!("Some other subcommand was used"),
}
// Continued program logic goes here...
}