macro_rules! calculate{
(eval $e:expr) =>{
{
let val:usize = $e;
println!("{} = {}",stringify!($e),val);
}
};
(eval $e:expr, $(eval $es:expr),+) =>{
calculate!{
eval $e
}
calculate!{
$(eval $es),+
}
}
}
fn main() {
calculate! {
eval 1 + 2,
eval 2* 3,
eval 4/2
}
}