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use std::ops::RangeInclusive;
use clap::Parser;
#[derive(Parser)]
#[command(author, version, about, long_about = None)]
struct Cli {
#[arg(value_parser = port_in_range)]
port: u16,
}
fn main() {
let cli = Cli::parse();
println!("PORT = {}", cli.port);
}
const PORT_RANGE: RangeInclusive<usize> = 1..=65535;
fn port_in_range(s: &str) -> Result<u16, String> {
let port: usize = s
.parse()
.map_err(|_| format!("`{}` isn't a port number", s))?;
if PORT_RANGE.contains(&port) {
Ok(port as u16)
} else {
Err(format!(
"Port not in range {}-{}",
PORT_RANGE.start(),
PORT_RANGE.end()
))
}
}