Rust macro for making variable from parsed string.

let_from_str.rs

macro_rules! let_from_str {
    ($($a:ident : $t:ty),+ = $s:expr) => {
        $(let $a: $t;)+
        {
            let mut _it = $s.split_whitespace();
            $($a = _it.next().unwrap().parse().unwrap();)+
            assert!(_it.next().is_none());
        }
    };
}

fn main() {
    let_from_str!(a:i32 = "123");
    println!("{}", a);
    let_from_str!(a:i32, b:f64, c:String = "1 2.3 45");
    println!("{} {} {}", a, b, c);
}