pub fn macro_show()
macro_rules! calculate { (eval $e:expr) => {{ { let val: usize = $e; // Force types to be integers println!("{} = {}", stringify!{$e}, val); } }}; } fn main() { calculate! { eval 1 + 2 // hehehe `eval` is _not_ a Rust keyword! } calculate! { eval (1 + 2) * (3 / 4) } }