Re: [Boost-bugs] [Boost C++ Libraries] #11234: boost::asymmetric_coroutine doesn't compile when used with boost::range::algorithms

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11234: boost::asymmetric_coroutine doesn't compile when used with boost::range::algorithms
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-04-27 09:37:12

#11234: boost::asymmetric_coroutine doesn't compile when used with
boost::range::algorithms
-------------------------------+-----------------------
  Reporter:  kozlov.taras@…    |      Owner:  olli
      Type:  Bugs              |     Status:  closed
 Milestone:  To Be Determined  |  Component:  coroutine
   Version:  Boost 1.58.0      |   Severity:  Problem
Resolution:  wontfix           |   Keywords:
-------------------------------+-----------------------

Comment (by kozlov.taras@…):

 First of all boost coroutines and ranges can't be used together at the
 moment. This is definitly a bug. And ok, probably it should be fixed in
 Boost.Range

 I want to clearify problem again. Using generator together with ANY non
 mutating Boost.Range algorithm yields compiler error

 Example
 {{{
 asymmetric_coroutine<int>::pull_type make_dummy_range()
 {
     return
 asymmetric_coroutine<int>::pull_type([](asymmetric_coroutine<int>::push_type&
 yield)
     {
         yield(1);
     });
 }

 int _tmain(int argc, _TCHAR* argv[])
 {
     boost::for_each(make_dummy_range(), ...); //error
     boost::max_element(make_dummy_range()); //error
     boost::distance(make_dummy_range()); //error
     boost::find(make_dummy_range(), 1); //error
 }
 }}}

 I put this bug to boost.coroutines for two reasons.

 1. It is known problem that SinglePassRange can't define perfect
 const_iterator, but it is also common and convinient workaround to
 override range_const_iterator to return mutable iterator. So any algorithm
 which accept const Range& can work with it.

 2. Coroutines in Boost 1.55 already provided const_iterator, so Boost 1.58
 just broken some existing code.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11234#comment:2>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.