Re: [Boost-users] Absolute Quanfusion : was Re: [fusion] transform avector of values to refs

8 Sep 2006

      "Andy Little"  wrote
<...>
...
Anyway I have continued hacking away and  so here is my latest efforts, using
fusion to do a dot product of two vectors.
Maybe it would be a useful example in the fusion docs?. Anyway here it is
FWIW:
A couple of bugs found in my code, as detailed below .  --->

Also I found I had to comment out the  specialisation of  as_vector<0>
in < boost/fusion/sequence/conversion/detail/as_vector.hpp>
in the Boost Review version to get it to compile OK in GCC4.0.1

I havent tried the CVS version of the file but it looks unchanged relative to my
version.

regards
Andy Little

<...>
...
// more arg reversing
template <typename F>
struct reverse_f_args{
template 
   struct result{
       typedef typename F:: template result<
           Rhs,Lhs
       >::type type;
   };
   template 
   typename result::type
   operator()( Rhs const & rhs, Lhs const & lhs )const
   {
       F f;

-        f(lhs,rhs);
+      return f(lhs,rhs);
----------------------
<...>
...
// do the dot_product

-
-   result_type result = boost::fusion::fold(
-
+
+        result_type result = 0;
+
+        boost::fusion::fold(
-------------------------------------------------
...
boost::fusion::transform(seq1,seq2,quan::operator_times()),
       boost::ref(result),
       quan::fusion::reverse_assign_f_argsquan::operator_plus_equals()
   );
   assert(quan::compare(result,30,1e-12) ==0);
   std::cout << result <<'\n';
}
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