Re: tuple_max in C++1x

On 11 Apr., 08:01, PGK wrote:


You mean C++0x.


Yes. You could unroll the loop via metaprogramming/recursion and
return a reference to the max element -- provided that the element
types are all the same. You chould start like this (untested):

   #include <tuple>
   #include <utility>

   template<int Remaining>
   struct tuple_for_each_helper
   {
     template<typename Tuple, typename Func>
     static void doit(Tuple & tup, Func & f)
     {
       const int ts = std::tuple_size<Tuple>::value;
       f( std::get<(ts-Remaining)>(tup) );
       tuple_for_each_helper<(Remaining-1)>::doit(tup,f);
     }
   };

   template<>
   struct tuple_for_each_helper<0>
   {
     template<typename Tuple, typename Func>
     static void doit(Tuple & tup, Func & f) {}
   };

   template<typename Tuple, typename Func>
   Func tuple_for_each(Tuple & tup, Func f)
   {
     const int ts = std::tuple_size<Tuple>::value;
     tuple_for_each_helper<ts>::doit(tup,f);
     return std::move(f);
   }

The rest follows from that. For example, you might want to use
tuple_for_each with a lambda expression. Alternativly, you could use
std::array instead of std::tuple. std::array allows indexing with
"runtime values".

Cheers,
SG

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