AMDG Jesse Perla wrote:

Take the following function: struct test_function { template<typename Vector, typename IntType> typename Vector::value_type operator()(const Vector& x, IntType bound_value) const{ return x[0] * x[0] + bound_value; } };

I wasn't sure exactly how the "type" member template pattern works so that result_of will work. I tried the following, but can't figure out how to extract the type of the arguments or convert to an MPL sequence? Is there some trick I am missing?

struct test_function { template<typename Args> struct result { //HOW TO CONVERT TO MPL SEQUENCE OR ANOTHER APPROACH? typedef typename boost::mpl::at_c<Args, 0 >::type::value_type type; };

template<typename Vector, typename IntType> typename Vector::value_type //The type in the vector... can be a double or AD type operator()(const Vector& x, IntType bound_value) const{ return x[0] * x[0] + bound_value; } };

struct test_function { template<typename Sig> struct result; template<typename This, typename Arg1, typename Arg2> struct result<This(Arg1, Arg2)> { typedef typename boost::remove_reference<Arg1>::type::value_type type; }; }; In Christ, Steven Watanabe