The example code.
~~~rust
use clap::{App, Arg};
fn main() {
let matches = App::new("My Super Program")
.arg(
Arg::with_name("verbose")
.help("Sets the level of verbosity")
.short('v')
.long("verbose")
.takes_value(false)
.multiple_occurrences(true)
.env("VERBOSE"),
)
.get_matches();
match matches.occurrences_of("verbose") {
0 => println!("0 No verbose info"),
1 => println!("1 Some verbose info"),
2 => println!("2 Tons of verbose info"),
3 | _ => println!("3 >= Don't be crazy"),
}
}
~~~
It code use multiple_occurrences with env.
But it do not work.
`env` method set require take value.
It result see under.
~~~console
% cargo run -- -v
Finished dev [unoptimized + debuginfo] target(s) in 0.01s
Running `target/debug/foo -v`
error: The argument '--verbose <verbose>...' requires a value but none was supplied
USAGE:
foo [OPTIONS]
For more information try --help
~~~
And, structopt or clap_derive may be create similar code.
So I am confused by structopt.
This to fix code small.
