tester.rs

fn main() {
    let mut rows = [[ 1, 2, 3, 4],
                    [ 5, 6, 7, 8],
                    [ 9,10,11,12],
                    [13,14,15,16]];

    for i in range(0, 4u) {
        for j in range(0, 3u) {
            /// Here's what I'd like to do
            if rows[i][j+1] == 0 {
                rows[i][j+1] = rows[i][j];
                rows[i][j] = 0;
            }
            /// Is there a way to pull that out into a function called like:
            combine(&mut rows[i][j], &mut rows[i][j+1]);
        }
        println!("\n------------");
    }
}