[boost] Re: cref(_1)

From: David Abrahams (dave_at_[hidden])
Date: 2004-04-11 21:39:57

John Torjo <john.lists_at_[hidden]> writes:

> David Abrahams wrote:
>
>>John Torjo <john.lists_at_[hidden]> writes:
>>
>>  
>>
>>>>It seems to me that, since I know that binding to an rvalue is
>>>>required, we ought to have a way to say "force this to be a const
>>>>ref".  I thought of something like
>>>>
>>>>       std::for_each(
>>>>           make_difference_iterator(p->second.begin())
>>>>         , make_difference_iterator(p->second.end())
>>>>         , boost::bind(&fu::writeVInt, &prox, boost::cref(_1)));
>>>> 
>>>>
>>>>      
>>>>
>>>How about constifying the original sequence?
>>>    
>>>
>>
>>That wouldn't help.
>>  
>>
>
> duh :D what was I thinking?
>
> However, I looked for difference iterator, and did not find any docs
> or anything else.

No, it's just something I cooked up here.

> So, for the above case, what's the difference_iterator's value_type
> and reference, 

say they're both int.

> and what's the writeVInt's signature?

let's say it's 

   void fu::writeVInt(something_that_int_is_convertible_to)

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com