[Boost-bugs] [Boost C++ Libraries] #4542: bind() should use boost::result_of

Subject: [Boost-bugs] [Boost C++ Libraries] #4542: bind() should use boost::result_of
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-08-14 20:25:38

#4542: bind() should use boost::result_of
--------------------------+-------------------------------------------------
 Reporter:  anonymous     |       Owner:  pdimov 
     Type:  Bugs          |      Status:  new    
Milestone:  Boost 1.44.0  |   Component:  bind   
  Version:  Boost 1.44.0  |    Severity:  Problem
 Keywords:                |  
--------------------------+-------------------------------------------------
 if at all possible boost::bind(F(),...) should use
 boost::result_of<F(...)> instead of directly accessing F::result_type.

 this way functors whose result type depends on the argument types could be
 used in bind(), for example:

 {{{
 #include <boost/bind.hpp>
 #include <boost/utility/result_of.hpp>

 using namespace boost;

 struct F{
   template<typename Args>
   struct result;
   template<typename T>
   T operator()(T const &t) const{ return t; }
 };

 template<typename T>
 struct F::result<F(T const &)>{
   typedef T type;
 };

 template<typename F>
 void g(F const &f){
   typename boost::result_of<F()>::type res=f();
 }

 int main(){
   f(bind(F(),4)); //error. no result_type in F
 }

 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4542>
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