Re: [Boost-users] [fusion] trouble with transform

Try this struct make_b { template<typename Sig> struct result; template <typename DS> struct result { typedef typename DS::B type; }; template <typename DS> struct result { typedef typename DS::B type; }; template <typename T> typename T::B operator()(T const& t) const { return t.make_b(); } }; or this struct make_b { template<typename Sig> struct result; template struct result { typedef typename DS::B type; }; template struct result { typedef typename DS::B type; }; template <typename T> typename T::B operator()(T const& t) const { return t.make_b(); } }; The latter code would be more robust, because the code allows both of boost::result_of and boost::result_of. Regards, Michel