Rust macro for making variables from a iterator.

let_from_iter.rs

macro_rules! let_from_iter {
    ($($a:ident),+ = $it:expr) => {
        $(let $a;)+
        {
            let mut _it = $it.into_iter();
            $($a = _it.next().unwrap();)+
            assert!(_it.next().is_none());
        }
    };
}

fn main() {
    let v = vec![1];
    let_from_iter!(a = v);
    println!("{}", a);
    let v = vec![1,2,3,4];
    let_from_iter!(b, c, d, e = v.iter());
    println!("{} {} {} {}", b, c, d, e);
    let v = vec![1,2];
    let_from_iter!(a = v); // should panic.
    println!("{}", a);
}