count, sum, and avg macros in rust

avg.rs

macro_rules! avg {
    ($($t:expr),*) => (sum!($($t),*)/count!($($t),*));
}

macro_rules! count {
    ($h:expr) => (1);
    ($h:expr, $($t:expr),*) =>
        (1 + count!($($t),*));
}

macro_rules! sum {
    ($h:expr) => ($h);
    ($h:expr, $($t:expr),*) =>
        ($h + sum!($($t),*));
}

fn main() {
    let i = avg![1,2,4,6,8,5,3,4,7,4,5,7];
    println!("{}", i);
}

I was trying to do the same sort of thing as an exercise. The only difference is that I called the macro on both sides of the operation (because I had debug println! calls).

macro_rules! sum {
    ($h:expr) => ($h);              // so that this would be called, I ...
    ($h:expr, $($t:expr),*) =>
        (sum!($h) + sum!($($t),*)); // ...call sum! on both sides of the operation
}

same with the count! macro:

macro_rules! count {
    ($h:expr) => (1);
    ($h:expr, $($t:expr),*) =>
        (count!(1) + count!($($t),*));
}

Edit: Oh, and I was using + instead of *.