Are iterators and ranges going to co-exist?

[Andrei Alexandrescu]

Steven Schveighoffer wrote:
> 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.

C-style strings and generally all sentinel-terminated sequences.

> 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.

To express such ranges in SList I used Take.


Andrei