"IndexType" for ranges

[Andrei Alexandrescu]

On 10/2/12 12:45 PM, Peter Alexander wrote:
> On Tuesday, 2 October 2012 at 16:29:28 UTC, Simen Kjaeraas wrote:
>> On 2012-10-02, 18:09, Peter Alexander wrote:
>>
>>> On Tuesday, 2 October 2012 at 13:17:45 UTC, monarch_dodra wrote:
>>>> If you've ever worked on a template that needs to index a range, you
>>>> may have run into this problem: What is the type you should use to
>>>> index an RA range?
>>>
>>> Forgive my ignorance. What's wrong with size_t?
>>
>> That not all ranges use it? If the range uses int, short, byte
>> (I wonder why they'd do it, though), using size_t will not even
>> compile.
>
> That's kind of my point. Unless there's a compelling reason not to, I'd
> suggest we standardise on size_t indexing (and length) and avoid this
> issue altogether.

Yes. Unfortunately there are few, few cases in which size_t is 
insufficient (e.g. an input range from a file or a large iota, both on 
32-bit builds). I personally think these are too few to need formal support.

> C++ containers have a size_type typedef. No one uses it.

Agreed.

> Let's keep things simple instead of complicating things for the sake of
> unwanted "flexibility".

Yes. We should curb some corner cases of current range design in the 
direction of simplifying things.


Andrei