<Oliver.Kowalke <at> qimonda.com> writes:
Hmm - what are the benefits/disadvantages of the two implementations - or which should you use?
[ I'm talking past because I abandoned the library when I was unable to implement multimethods. ] dynamic_any's goal was to mimic values of scripting languages. For example, one could subtract a number from a string containing numeric value and print the result: dynamic_any< /* list of supported operations */ > a("2"), b(1); cout << a - b; Function calls is one particular case of "operation". calls.cpp (http://tinyurl.com/373wkx) defines a list of operations as follow: typedef mpl::list< dynamic_any::function_call<int (int)>, dynamic_any::function_call<double (double)>
ops;
At construction time, a single value functor is created. It must be a functor that can accept one argument of type int or double: dynamic_any<ops> f(_1 + 1); // lambda expression cout << f(136) << '\n'; cout << f(2.1459) << '\n'; This means that any dynamic_any value which supports these operations is callable. You can pass either int or double to such dynamic_any values. Key difference between my interface and Joel's is that Joel sets overloads individually: f.set<0>(&foo1); f.set<1>(&foo2); f.set<2>(&foo3); f.set<3>(&foo4); while I expect a single functor supporting all overloads: _1 + 1; or struct f { int operator(int) const; double operator(double) const; }; -- Alexander