[Boost-bugs] [Boost C++ Libraries] #6373: transform_iterator not preserving bidirectionality of std::map iterator

Subject: [Boost-bugs] [Boost C++ Libraries] #6373: transform_iterator not preserving bidirectionality of std::map iterator
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-01-10 02:15:30


#6373: transform_iterator not preserving bidirectionality of std::map iterator
-------------------------------------------------------+--------------------
 Reporter: JonT <jon@…> | Owner: dave
     Type: Bugs | Status: new
Milestone: To Be Determined | Component: iterator
  Version: Boost 1.49.0 | Severity: Problem
 Keywords: transform_iterator bidirectional std::map |
-------------------------------------------------------+--------------------
 Using transform_iterator on std::map iterator does not seem to preserve
 bidirectionality.

 {{{
 #!cpp
 map::iterator itend = data.end();
 XIt xend = boost::make_transform_iterator(itend,xfunc());
 XIt xlast = xend;
 --xlast;
 assert(xend != xlast); // succeeds !
 xlast = xend;
 std::advance(xlast,-1);
 assert(xend != xlast); // fails !
 }}}

 See also [http://stackoverflow.com/questions/8783048/bidirectional-boost-
 transform-iterator-as-with-stdmap StackOverflow Issue 8783048] for longer
 (compilable) example.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6373>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.

This archive was generated by hypermail 2.1.7 : 2017-02-16 18:50:08 UTC