Re: [Boost-bugs] [Boost C++ Libraries] #6869: spirit lex use phoenixV3 compile error

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #6869: spirit lex use phoenixV3 compile error
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2017-12-05 19:28:08

#6869: spirit lex use phoenixV3 compile error
-------------------------------+----------------------------
  Reporter:  anonymous         |      Owner:  Joel de Guzman
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  spirit
   Version:  Boost 1.49.0      |   Severity:  Problem
Resolution:                    |   Keywords:  spirit lex
-------------------------------+----------------------------

Comment (by Nikita Kniazev <nok.raven@…>):

 The Spirit examples wrongly uses `result_of` protocol. I am working on
 fixing examples, but it is still WIP. To fix your problem, you should fix
 `distance_func` like this:

 {{{#!cpp
 struct distance_func
 {
     template <typename Sig>
     struct result;

     template <typename F, typename Iterator1, typename Iterator2>
     struct result<F(Iterator1 const&, Iterator2 const&)>
         : boost::iterator_difference<Iterator1>
     {};

     template <typename F, typename Iterator1, typename Iterator2>
     struct result<F(Iterator1&, Iterator2&)>
         : result<F(Iterator1 const&, Iterator2 const&)>
     {};

     template <typename Iterator1, typename Iterator2>
     typename result<distance_func(Iterator1&, Iterator2&)>::type
         operator()(Iterator1& begin, Iterator2& end) const
     {
         return std::distance(begin, end);
     }
 };
 }}}

 Or it could be a little simpler (`std::distance` requires both iterators
 to have the same type):
 {{{#!cpp
 struct distance_func
 {
     template <typename>
     struct result;

     template <typename F, typename Iterator>
     struct result<F(Iterator, Iterator)>
         : boost::iterator_difference<typename
 boost::decay<Iterator>::type>
     {};

     template <typename Iterator>
     typename result<distance_func(Iterator&, Iterator&)>::type
         operator()(Iterator& begin, Iterator& end) const
     {
         return std::distance(begin, end);
     }
 };
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac10/boost/ticket/6869#comment:2>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.