1 2 3 4 5 6 7 8 9 10 11 12 13 14
macro_rules! mock_dbg { ($express:expr) => { println!("express: {:?} = {:?}", stringify!($express), $express); }; } fn main() { mock_dbg!(1 + 2); mock_dbg!({ let mut a = "a".to_string(); a.push('b'); a }); }