RFC on range design for D2

[Andrei Alexandrescu]

Steven Schveighoffer wrote:
> "Andrei Alexandrescu" wrote
> For example, std::list defines multiple erase functions:
> 
> iterator erase(iterator first, iterator last);
> iterator erase(iterator position);
> 
> In the second case, the iterator need not support incrementing or 
> decrementing (to the user anyway), just referencing.  They just used 
> iterator because it's already there :)
> 
> But in your proposed scenario, I can't have the second function, only the 
> first.  My example shows a case where I'd want the second function.  What I 
> basically want is a range type where the upper limit is specified as 'always 
> null', so that iterating the range once always results in an empty range, 
> even if the container has changed topology.

I understand. That can't be had in my design. You'd have:

List.Range List.erase(Range toErase);

and you'd model erasure of one element through a range of size one. I 
understand how that can be annoying on occasion, but I consider that a 
minor annoyance and do not plan to allow bare iterators for such cases. 
I think the absence of naked iterators has huge cognitive and safety 
advantages.


Andrei