Re: [boost] AlRangeExandrescu?

Subject: Re: [boost] AlRangeExandrescu?
From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2009-07-25 03:47:01

Andrei Alexandrescu skrev:
> Mathias Gaunard wrote:

>>> You would pass two adjacent ranges, like D's bringToFront (a 
>>> generalization of STL's rotate, see 
>>> http://www.digitalmars.com/d/2.0/phobos/std_algorithm.html) takes.
>>
>> Nice idea, that could work.
>> But how can I generate those two adjacent ranges in the first place at 
>> reasonable costs? Do ranges requires to provide a constant time 
>> "complement" primitive?
> 
> There's no such need (a range could define it though).
> 
> A design that has a bidirectional iterator walking freely up and down 
> between two limits would be difficult to port to ranges. (If the 
> iterator is random-access, things are trivial.) Ranges can only shrink, 
> they never grow unless assigned from the outside. So when you move one 
> direction it would be difficult to grow one range (shrinking the other 
> is easy). That design would benefit from letting the iterator 
> abstraction exposed.

Couldn't it be done with a special range that stores three iterators?

-Thorsten