clap/examples/keyvalue-derive.rs
Ed Page 03cb509d6c refactor(examples): Change naming style
This is to make room for a reasonable looking cargo plugin example.

I got lazy and didn't update the tutorials.
2021-12-15 11:12:18 -06:00

29 lines
763 B
Rust

// Note: this requires the `derive` feature
use clap::Parser;
use std::error::Error;
#[derive(Parser, Debug)]
struct Args {
#[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);
}