Explanation for listing 15-7 has strange phrasing

[nahla-nee]

list 15-7 has the following code snippet:

fn main() {
    let x = 5;
    let y = Box::new(x);

    assert_eq!(5, x);
    assert_eq!(5, *y);
}

With the following explanation

The only difference between Listing 15-7 and Listing 15-6 is that here we set y to be an instance of a box pointing to the value in x rather than a reference pointing to the value of x.

This is confusing because y is not pointing to the value of x, it created a copy of x's value and stored that in the heap. The explanation suggests (to me at least) that *y and x refer to the same location in memory

[sl4m]

I noticed this as well. What do you think would be a better explanation? I thought about modifying the listing example to something like this, but it does stray slightly away from the previous listing (15-6)

fn main() {
    let mut x = 5;
    let y = Box::new(x);
    
    x += 1;
    assert_eq!(6, x);
    assert_eq!(5, *y);
}

[nahla-nee]

maybe something like this?

The only difference between Listing 15-7 and Listing 15-6 is that here we set y to be an instance of a box pointing to a new integer with the same value as x, rather than a reference pointing to the value of x.

[sl4m]

maybe something like this?

The only difference between Listing 15-7 and Listing 15-6 is that here we set y to be an instance of a box pointing to a new integer with the same value as x, rather than a reference pointing to the value of x.

I think that reads a lot better. 👍 Shall it mention copy at all? Otherwise, maybe one of us can create a PR?

[nahla-nee]

you can feel free to create the PR if you want. As far as copying I feel that is implied since you can't get a new value that is the same as the one x had without copying the value of x, but it maybe better to be verbose about it, i'll leave that up to you.

[nahla-nee]

oop wrong button