| #[macro_use] |
| extern crate structopt; |
| |
| use std::error::Error; |
| use structopt::StructOpt; |
| |
| fn parse_key_val<T, U>(s: &str) -> Result<(T, U), Box<Error>> |
| where |
| T: std::str::FromStr, |
| T::Err: Error + 'static, |
| U: std::str::FromStr, |
| U::Err: Error + 'static, |
| { |
| let pos = s |
| .find('=') |
| .ok_or_else(|| format!("invalid KEY=value: no `=` found in `{}`", s))?; |
| Ok((s[..pos].parse()?, s[pos + 1..].parse()?)) |
| } |
| |
| #[derive(StructOpt, Debug)] |
| struct Opt { |
| #[structopt(short = "D", parse(try_from_str = "parse_key_val"))] |
| defines: Vec<(String, i32)>, |
| } |
| |
| fn main() { |
| let opt = Opt::from_args(); |
| println!("{:?}", opt); |
| } |