Requirements for Slicing Ranges

[Sebastiaan Koppe]

On Monday, 2 September 2024 at 11:53:55 UTC, Paul Backus wrote:
> On Monday, 2 September 2024 at 09:59:04 UTC, Sebastiaan Koppe 
> wrote:
>>
>> I briefly wondered how it would work if the range is 
>> non-copyable, since taking a slice is effectively taking a 
>> copy of the underlying data the range captures (and its 
>> lifetime).
>
> Taking a slice does not necessarily copy the range, nor does it 
> necessarily copy the range's elements.
>

Apologies, I expressed myself poorly, and I have to admit it is a 
bit of a stretch.

I meant that taking a slice often creates another alias to the 
same data and/or state or part thereof.

This is in contrast to indexing, which just returns the 
underlying item, possible as value.

If you would want to restrict/control a range so much so that you 
make it non-copyable, you could argue you would want to avoiding 
taking a slice from it as well. It might very well have random 
access though, so you would end up with one that exposes indexing 
but not slicing.