I was looking at the function_traits implementation in the Boost CVS, and saw that it might benefit from adding a tuple-like interface to the function_traits type. I'm thinking along the lines of: typedef function_traits<void(int,char,bool)> sample_trait; at_c<sample_trait::args, 1>::type a; // char at_c<sample_trait::args, 3>::type b; // error, out of bounds ? typedef function_traits<void( tuple<int, char, bool> , std::string )> another_sample; at< typename at_c<another_sample::args, 0>::type, 0 >::type c; // int Perhaps adding a mpl::vector or a fusion::vector element 'args' can greatly improve the kinds of things that can be done with the function_traits<>, especially in libraries aiming to become more flexible when it comes to argument pack handling. I got the idea because I found myself needing a generic way of defining a tuple from the argument list of a signatures passed to function_traits<>. That's a pretty simple use case, but I found myself having to do some repetitive overloads to accommodate the 10 variations of function_traits using just the function_traits<>::arity element, and then having to do PP magic to iterate through the `argN_type' typedefs. With the additional `args' fusion/mpl vector in function_traits<>, it wouldn't have to be a concern since it already packs the types of the arguments. Defining operations over args could very well be a simple exercise in template metaprogramming. If anybody's interested, it's a pretty trivial patch attached. -- Dean Michael C. Berris http://cplusplus-soup.blogspot.com/ mikhailberis AT gmail DOT com +63 928 7291459