Re: [boost] [iterator] could non-small predicates/functors be stored as boost::optional<T> to avoid double construction?

Subject: Re: [boost] [iterator] could non-small predicates/functors be stored as boost::optional<T> to avoid double construction?
From: David Abrahams (dave_at_[hidden])
Date: 2008-09-04 10:08:04

on Thu Sep 04 2008, Thorsten Ottosen <thorsten.ottosen-AT-dezide.com> wrote:

> Arno Schödl skrev:
>>> Hi,
>>
>>> The headline pretty much says it all. Take transform iterator. When the
>>> predicate is not trivial, we also have a redundant construction of the object
>>> in the end iterator. Maybe that could be removed?
>>
>>> best regards
>>
>>> -Thorsten
>>
>> I guess that would be restricted to forward iterators.
>
> This has nothing to do with the wrapped iterator's type. A transform iterator
> currently stores a functor by value in addition to the wrapped iterator.

Have you forgotten

  *--end

?
-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com