Something about Rust Macros

macros-concat_idents.rs

macro_rules! test(
    ($x:ident) => ({
        let z = concat_idents!(hello_, $x);
        z();
    })
)

fn hello_world() { ... }

fn main() {
    test!(world);
}

macros-iterator.rs

macro_rules! iterator{
    ($ty:ty, $ident:ident;
     $($state_ident:ident: $state_ty:ty), *;
     $next:expr) => (
        struct $ident {
            $($state_ident: $state_ty), *
        }

        impl Iterator for $ident {
            type Item = $ty;

            fn next(&mut self) -> Option<$ty> {
                $next(self)
            }
        }
    );
}

iterator!(i32, TestIterator; index: i32; |me: &mut TestIterator| {
    let value = Some(me.index);
    me.index += 1;
    value
});

fn main() {}

macros-sorted_vec.rs

macro_rules! sorted_vec {
    ($($x:tt)*) => {
        {
            let mut v = vec![$($x)*];
            v.sort();
            v
        }
    }
}