macro_rules! postfix {
    // Terminating rule
    (() -> ($res:expr)) => {$res};

    // Addition
    ((+ $($rest:tt)*) -> ($a:tt $b:tt $($stack:tt)*)) => {
        postfix!(($($rest)*) -> (($b + $a) $($stack)*))
    };
    
    // Subtraction
    ((- $($rest:tt)*) -> ($a:tt $b:tt $($stack:tt)*)) => {
        postfix!(($($rest)*) -> (($b - $a) $($stack)*))
    };
    
    // Multiplication
    ((* $($rest:tt)*) -> ($a:tt $b:tt $($stack:tt)*)) => {
        postfix!(($($rest)*) -> (($b * $a) $($stack)*))
    };
    
    // Divison
    ((/ $($rest:tt)*) -> ($a:tt $b:tt $($stack:tt)*)) => {
        postfix!(($($rest)*) -> (($b / $a) $($stack)*))
    };
    
    // Push operands onto the stack
    (($d:tt $($rest:tt)+) -> ($($stack:tt)*)) => {
        postfix!(($($rest)+) -> ($d $($stack)*))
    };
    
    // Start
    ($($ops:tt)+) => {
        postfix!(($($ops)+) -> ())
    };
}

fn main() {
    let res = postfix!(15 7 1 1 + - / 3 * 2 1 1 + + -);
    println!("{}", res);
}