Are iterators and ranges going to co-exist?

[Steven Schveighoffer]

On Tue, 20 Jul 2010 09:52:00 -0400, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> On 07/20/2010 03:01 AM, Peter Alexander wrote:
>> Some more arguments for iterators/cursors:
>>
>> 1. How would you implement Floyd's cycle finding algorithm using ranges?
>> (http://en.wikipedia.org/wiki/Cycle_detection#Tortoise_and_hare)
>> It uses two iterators over the same range. You would have to wastefully
>> use 2 ranges that have the same end coordinate.
>
> I think there's a confusion somewhere. You may want to check out the  
> SList definition in std.algorithm. A SList range is exactly one pointer  
> thick. With singly-linked lists it's the iterator approach that is  
> wasteful because it canonically transports a null pointer as end().

That is an example of a single exception to the rule :)  AFAIK, no other  
container types have ranges with no end pointer or length.

It also makes SList ranges less expressive.  For example, what if I wanted  
a range between two elements in the list?  Such a range is actually  
unconstructable.  SList is not a very good example of a container, because  
it is so unique and limited.

-Steve