Re: [boost] [BGL] Visual Studio 12 finish_edge() failure, general BOOST_TTI_HAS_MEMBER_FUNCTION failure?

Subject: Re: [boost] [BGL] Visual Studio 12 finish_edge() failure, general BOOST_TTI_HAS_MEMBER_FUNCTION failure?
From: Michael Behrns-Miller (m_at_[hidden])
Date: 2014-04-01 16:12:06

On 4/1/2014 8:45 AM, Edward Diener wrote:
> On 4/1/2014 4:50 AM, Michael Behrns-Miller wrote:
>> On 4/1/2014 4:40 AM, Michael Behrns-Miller wrote:
>>> On 3/31/2014 6:30 PM, Edward Diener wrote:
>>>> On 3/31/2014 1:27 PM, Michael Behrns-Miller wrote:
>>>>> ...
>>>>> Here's how BGL defines it:
>>>>>
>>>>> -------------
>>>>>
>>>>>      BOOST_TTI_HAS_MEMBER_FUNCTION(finish_edge)
>>>>>
>>>>>      template <bool IsCallable> struct do_call_finish_edge {
>>>>>        template <typename E, typename G, typename Vis>
>>>>>        static void call_finish_edge(Vis& vis, const E& e, const G& 
>>>>> g) {
>>>>>          vis.finish_edge(e, g);
>>>>>        }
>>>>>      };
>>>>>
>>>>>      template <> struct do_call_finish_edge<false> {
>>>>>        template <typename E, typename G, typename Vis>
>>>>>        static void call_finish_edge(Vis&, const E&, const G&) {}
>>>>>      };
>>>>>
>>>>>      template <typename E, typename G, typename Vis>
>>>>>      void call_finish_edge(Vis& vis, const E& e, const G& g) { // 
>>>>> Only
>>>>> call if method exists
>>>>> do_call_finish_edge<has_member_function_finish_edge<Vis,
>>>>> void>::value>::call_finish_edge(vis, e, g);
>>>>>      }
>>>>
>>>> The invocation of has_member_function_finish_edge has to match the
>>>> member function signature which you are invoking. If the member
>>>> function signature for finish_edge is:
>>>>
>>>> void finish_edge(const E&, const G&);
>>>>
>>>> then your invocation for do_call_finish_edge must be:
>>>>
>>>> do_call_finish_edge
>>>>   <
>>>>   has_member_function_finish_edge
>>>>     <
>>>>     Vis,
>>>>     void,
>>>>     boost::mpl::vector
>>>>       <
>>>>       const E&,
>>>>       const G&
>>>>       >
>>>>     >
>>>>   ::value
>>>>   >::call_finish_edge(vis, e, g);
>>>>
>>>> or
>>>>
>>>> do_call_finish_edge
>>>>   <
>>>>   has_member_function_finish_edge
>>>>     <
>>>>     void Vis::* (const E&,const G&)
>>>>     >
>>>>   ::value
>>>>   >::call_finish_edge(vis, e, g);
>>>>
>>>>
>>>> _______________________________________________
>>>> Unsubscribe & other changes:
>>>> http://lists.boost.org/mailman/listinfo.cgi/boost
>>>
>>> Thank you Edward.
>>>
>>> The instantiation code was not mine, that is what is done by the BGL,
>>> here:
>>>
>>>     boost\graph\depth_first_search.hpp
>>>
>>> The instantiation code does not seem to match your recommendation.
>>> This simple DFS test fails:
>>>
>>> https://svn.boost.org/trac/boost/attachment/ticket/9770/test.cc
>>>
>>> So it sounds like BGL needs some patching to match your format. It
>>> should change from...
>>>
>>> do_call_finish_edge<has_member_function_finish_edge<Vis,
>>> void>::value>::call_finish_edge(vis, e, g);
>>>
>>> to...
>>>
>>> do_call_finish_edge<has_member_function_finish_edge<void Vis::* (const
>>> E&,const G&)>::value>::call_finish_edge(vis, e, g);
>>>
>>> Does that sound correct?
>>
>> On the newer code, Visual Studio 12 gives me:
>>
>>      boost_1_55_0/boost/graph/depth_first_search.hpp(86): error C2182:
>> 'abstract declarator' : illegal use of type 'void'
>
> I am the developer for TTI. In your test case the actual VIZ struct 
> has templated member functions, so I do not think has_member_function 
> will find your templated functions. TTI is a compile-time mechanism 
> for producing compile-time code. But even if it does not find the 
> member functions at compile-time TTI should not produce a compile-time 
> error so I definitely want to look at this situation.
>
> As to why Visual Studio 12 gives that error I need to be able to 
> reproduce your compile steps. I am an absolute novice with the Boost 
> graph library. I think I need to build the library first, then run 
> your test against it.
>
> Jeremiah Willcock produced the changes in graph using TTI so he may 
> have had a very good reason for using the original has_member_function 
> signature, although it looks wrong to me on purely a TTI basis. 
> Hopefully he will chime in on his change.
>
>
>
> _______________________________________________
> Unsubscribe & other changes: 
> http://lists.boost.org/mailman/listinfo.cgi/boost

Thanks Edward, appreciate the feedback, I'll be monitoring.  In the 
meantime my workaround of making finish_edge() non-optional is working 
for me.  But of course I'd prefer not to have to change boost code 
before using.  :-)

Sure appreciate all you guys do to develop and maintain the libraries, 
boost is just fantastic.