why required arg is always None？

[StringKe]

use clap::{Arg, App};

fn main() {
    let matches = App::new("test_demo")
        .version("1.0")
        .author("StringKe")
        .about("about information")
        .arg(Arg::with_name("test-demo").long("test-demo").help("test-demo arg").required(true))
        .get_matches();

    println!("{:?}", matches.value_of("test-demo"));
}

output:

➜ cargo run -- --test-demo=123
    Finished dev [unoptimized + debuginfo] target(s) in 0.07s
     Running `target/debug/text_render --test-demo=123`
None

Do I need to call other methods to get the value?

[pksunkara]

It doesn't take value. Which means you need to call is_present

[StringKe]

Can I get the value if is_present return true?

[pksunkara]

No, because you haven't specified that arg will take value. Please read the documentation properly.

[StringKe]

NOTE: get value must use one of the takes_value or index method