Re: [boost] Interest in bounded (Top-Bounded) Range adaptor.

Subject: Re: [boost] Interest in bounded (Top-Bounded) Range adaptor.
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-10-28 20:28:00

on Thu Oct 27 2011, Fernando Pelliccioni <fpelliccioni-AT-gmail.com> wrote:

> Is there interest in adding a Top-Bounded adaptor into Boost.Range ?
>
> Example:
>
>   using namespace boost::adaptors;
>   using namespace boost::assign;
>
>   std::vector<int> input;
>   input += 1,2,3,4,5,6,7,8,9;
>
>   boost::copy( input | bounded(0), std::ostream_iterator<int>(std::cout,
> ","));            // prints nothing
>   boost::copy( input | bounded(1), std::ostream_iterator<int>(std::cout,
> ","));            // prints 1,
>   boost::copy( input | bounded(2), std::ostream_iterator<int>(std::cout,
> ","));            // prints 1,2,
>   boost::copy( input | bounded(8), std::ostream_iterator<int>(std::cout,
> ","));            // prints 1,2,3,4,5,7,8,
>
> Is there interest in this for Boost?

There is an obvious generalization that stops the range when a
predicate is satisfied, e.g.

  boost::copy( input | until(_1 == 8), 
               std::ostream_iterator<int>(std::cout, ","));

That leads me to believe that the proper behavior of the
less-generalized component, which you call "bounded," is to stop the
range when the element reaches the bound, rather than including it.

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