Re: PointerWrapper Trait vs croe::ops::Deref

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

On Sun, May 9, 2021 at 12:25 PM Finn Behrens <me@kloenk.de> wrote:
>
> Maybe we could also remove the result, as it would possible be an invariant, and never happen as the pointer should already be valid.

If it can fail, we cannot use `Deref` to begin with. So yeah, to make
the examples equivalent, the first one should not return a `Result`.

Now, assuming it cannot fail, what I mentioned in the meeting is that
with `Deref` all this compiles:

    wrapper.deref().number
    (*wrapper).number
    wrapper.number

The question boils down to: do we want this shortcut or not?

Having said that, I am not sure I understand the traits shown here.
Isn't `PointerWrapper` meant only to save a `Box<T>` and similar types
(which already implement `Deref` themselves etc.) as a pointer in a C
data structure? (which is why `into_pointer()` consumes the object).

In the examples shown, the new `get_pointer()` does not consume
`self`; and `main()` creates a `Wrapper` using `from_pointer()`. But
the idea is that you already have an object (constructed via other
means), transform it into a raw pointer, and then later on
re-construct the original object back from that pointer.

So `PointerWrapper` trait is like a `SavedAsPointer` trait, if you will.

Cheers,
Miguel