fn free_floating(i32 arg1, i32 arg2) ReturnType {
    let local_var = arg1 + arg2;
}

// associated function for the World struct
World mut fn set_next(i32 i, i32 j) {
    // members on this World struct can be accessed with `.`
    let mut numdots = .numdots; // mutable variables are defined with `let mut`
    let neighbors = count_neighbors(.current, i, j);

    // `if` statements are expressions
    let next = if .current.get(i, j) == 0 {
        if neighbors != 3 {
            0
        } else {
            numdots++;
            1
        }
    } else {
        // Python-like `or` operator
        if neighbors == 2 or neighbors == 3 {
            1
        } else {
            numdots--;
            0
        }
    };

    if next != 0 {
        if i < .xmin { .xmin = i; }
        if i > .xmax { .xmax = i; }
        if j < .ymin { .ymin = j; }
        if j > .ymax { .ymax = j; }
    }
}