Index Pointers

In my post on Linked Lists I allude to this excellent post, Learn Rust with Entirely Too Many Linked Lists.

In that post the author lists many of the reasons why implementing a Linked List from scratch might be a bad idea, and the official rust documentation for std::collections::LinkedList nudges us in a similar way...

"It is almost always better to use Vec or VecDeque because array-based containers are generally faster, more memory efficient, and make better use of CPU cache."

But what might they mean by this?!

Are they suggesting that we use a Vec instead of a linked list? Or Use a Vec as as linked list?

I actually think they mean both..., use a vanilla Vec whereever possible and where that is insufficient, implement a Linked List by doing something like this:

The high-level idea is that we will represent a “pointer” to the next item in the list using an index.

let my_linked_list = vec![(Some(1), "hello"), (Some(2), "world")];

let mut head = my_linked_list[0];

loop {
    let (next, val) = head;
    match next {
        Some(nx) => {
            println!("{}", val);
            head = my_linked_list[nx];
        },
        _ => {
            break;
        }
    }
}

I guess you could call these index pointers.