Rant time? Rant time.

[IGotD-]

On Tuesday, 22 September 2020 at 10:00:46 UTC, Ola Fosheim 
Grøstad wrote:
>
> I believe Microsoft has a research language where ownership is 
> tied to a group of objects.
>
> I actually think C++'s model works out ok, when you add custom 
> allocators to the mix. But it would be better if the compiler 
> could ellide allocations or simply avoid calling 
> side-effect-free destructors if the entire (local) allocator 
> pool was released. I also want compiler support for embedded 
> refcounts (shared_ptr is costly).
>
> There is no certain way to establish how memory is allocated 
> and released in C++, so that does prevent (analytical) 
> optimization opportunities.
>
> The key challenge is really providing some mechanisms that 
> makes memory management, initialization and finalization 
> analytically tractable and providing more optimization 
> opportunities.
>
> (I think "provably memory safe" is too expensive in terms of 
> development freedom and time, so ignore that aspect. "Safer" is 
> good enough. "Safe" isn't really needed or realistic.)

Pony is another language that allows objects cross referencing 
but just like the Microsoft research language they have something 
called "regions" in which the objects are allowed to cross 
reference.

In Rust you pretty much are required to use Rc (reference count) 
+ RefCell (runtime bottow checker) for cross references or when 
there isn't a single ownership. That means that Rust suddenly 
becomes a garbage collected language + it must track borrow 
checker in runtime because the compiler cannot know that during 
compile time. This of course adds overhead code which I would 
consider in many cases unnecessary.