[Boost-bugs] [Boost C++ Libraries] #10894: Add an adaptor to iterate a range in pairs of (current element, next element)

Subject: [Boost-bugs] [Boost C++ Libraries] #10894: Add an adaptor to iterate a range in pairs of (current element, next element)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-12-23 12:07:00

#10894: Add an adaptor to iterate a range in pairs of (current element, next
element)
-------------------------------------------------+-------------------------
 Reporter:  Matthäus Brandl (brandl.matthaeus@…  |      Owner:  neilgroves
     Type:  Feature Requests                     |     Status:  new
Milestone:  To Be Determined                     |  Component:  range
  Version:  Boost Development Trunk              |   Severity:  Not
 Keywords:  range adaptor pairwise               |  Applicable
-------------------------------------------------+-------------------------
 An often needed functionality is iterating a range and accessing the
 current and next element of the range.

 Currently this can be done as follows:
 {{{#!C++
 assert(someVec.size > 1);
 for(auto const & pair, boost::make_iterator_range(
     boost::make_zip_iterator(
         boost::make_tuple(
             someVec.cbegin(), std::next(someVec.cbegin()))),
     boost::make_zip_iterator(
         boost::make_tuple(
             std::prev(someVec.cend()), someVec.cend())))
         )
 {
     auto current = boost::get<0>(pair);
     auto next    = boost::get<1>(pair);
 }
 }}}

 An adaptor would strongly increase readability:
 {{{#!C++
 assert(someVec.size > 1);
 using boost::adaptors::operator|;
 for(auto const & pair, someVec | boost::adaptors::paired())
 {
     pair.current();
     pair.next();
 }
 }}}

 Of course the difference between current and next could be made
 customizable as well.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10894>
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