clap/examples/typed-derive.rs
2022-03-14 09:49:46 -05:00

42 lines
1.2 KiB
Rust

// Note: this requires the `derive` feature
use clap::Parser;
use std::error::Error;
#[derive(Parser, Debug)]
struct Args {
/// Implicitly using `std::str::FromStr`
#[clap(short = 'O')]
optimization: Option<usize>,
/// Allow invalid UTF-8 paths
#[clap(short = 'I', parse(from_os_str), value_name = "DIR", value_hint = clap::ValueHint::DirPath)]
include: Option<std::path::PathBuf>,
/// Allow human-readable durations
#[clap(long)]
sleep: Option<humantime::Duration>,
/// Hand-written parser for tuples
#[clap(short = 'D', parse(try_from_str = parse_key_val), multiple_occurrences(true))]
defines: Vec<(String, i32)>,
}
/// Parse a single key-value pair
fn parse_key_val<T, U>(s: &str) -> Result<(T, U), Box<dyn Error + Send + Sync + 'static>>
where
T: std::str::FromStr,
T::Err: Error + Send + Sync + 'static,
U: std::str::FromStr,
U::Err: Error + Send + Sync + 'static,
{
let pos = s
.find('=')
.ok_or_else(|| format!("invalid KEY=value: no `=` found in `{}`", s))?;
Ok((s[..pos].parse()?, s[pos + 1..].parse()?))
}
fn main() {
let args = Args::parse();
println!("{:?}", args);
}