Rust code shared from the playground

playground.rs

/* Can you do better?
 *
 * The following code tries to initialize an array of somehow complex structures
 * I added also the dumb way to do that with maps and vectors
 * I wonder if adding some syntactic sugar such as 
 *
 * let array = [{|index| generator(index)}; N];
 * 
 * Could be interesting or hadn't been proposed already.
 *
 * lu_zero
 */

use std::mem;

#[derive(Debug)]
struct Codebook<T> {
    x: T,
    y: T
}

fn fill_thing_array(a : &mut [[Codebook<u8>; 4]; 4]) {
    for (i, line) in a.iter_mut().enumerate() {
        for (j, el) in line.iter_mut().enumerate() {
            *el = Codebook { x: i as u8, y: j as u8};
        }
    }
}

fn build_thing_vec() {
    let a : Vec<Vec<Codebook<u8>>> = (0..4).map(|i| {
        (0..4).map(|j| Codebook {x:i, y:j}).collect()
    }).collect();  

    println!("{:?}", a);
}

fn main() {
    let mut a = unsafe { mem::uninitialized() };
    fill_thing_array(&mut a);
    println!("{:?}", a);
    build_thing_vec();
    
}