fn main() {
    // We can turn pointers (including function pointers) into integral types.
    let f: fn(i32) -> i32  = |x| {x+2};
    let g = f as usize;

    // But we can also discard percision. Why? What's the possible use case?
    let h = f as u8;
    // It seems like this should require:
    // let h = f as usize as u8;

    println!("g = {:#x}, h = {:#x}", g, h);
    unsafe {
        // A use case like this would be useful in some sort of FFI.
        let f = std::mem::transmute::<usize, fn(i32) -> i32>(g);
        println!("The answer is {}", f(40));
    }
}