James Porter wrote:
That's the plan, but I was writing for gcc 4.3, and auto is only available in gcc 4.4. :)
Well, bind has an unspecified return type, and that never bothered anyone. If you don't have auto, just don't make it a named variable.
Does your memoize adaptor require knowing the signatures of the function object?
arbitrary function objects can have many overloads of operator(), and there would need to be a way to specify which overload is associated with the memoizer.
Can't you just do something like template<typename F> struct memoizer { memoizer(F f_) : f(f_) {} typedef typename boost::result_of<F>::type result_type; template<typename T1, typename T2, ..., typename Tn> result_type operator()(T1 t1, T2 t2, ..., Tn tn) { typedef boost::tuple<T1, T2, ..., Tn> tuple_type; typedef std::map< tuple_type, result_type > map_type; static map_type values; tuple_type tuple = boost::make_tuple(t1, t2, ..., tn); map_type::iterator it = values.find(tuple); if(it == values.end()) it = values.insert( std::make_pair(tuple, f(t1, t2, ..., tn)) ).first; return *it; } private: F f; }; template<typename F> memoizer<F> memoize(F f) { return memoizer<F>(f); } With ... standing for preprocessing magic.