On Sat, May 10, 2008 at 6:08 PM, Giovanni Piero Deretta <gpderetta@gmail.com> wrote:
Well my idea was that an unconstrained template function object would be bound to all internal boost::functions
You mean something like this template<int> struct end_seq_tag { typedef int type; }; template<> struct end_seq_tag<-1> { typedef char type; }; template<int n, typename T> void assign(T const& t, int*) { /* first convert to boost::function then add */ *this += boost::function< at_c<n, Signatures>::type >(t); assign<n - 1>(t, (end_seq_tag<n - 1>::type*)0); /* iterate */ } template<int n, typename T> void assign(T const&, char*) {} /* end condition here */ template<typename T> function& operator=(T const& t) { assign<signatures_size - 1>(t, (end_seq_tag<signatures_size - 1>::type*)0); return *this; } I have written fast, probably there is a better way, but just to show the idea. Is this what you mean ?
I think that in your case, using operator= is confusing because you are not really reassigning the MSF but just adding an overload. What if operator= tries to bind all signatures at once (and thus allows for boost::function like adaptability) and operator+= (or an explicit add member function) is strict and allows to replace a single overload?
operator+= is a nice idea, like an explicit set() or add() method. I have been stick to operator=() just to follow boost::function API, but I agree in case of MSF this could be confusing...
Where boost.function naturally models a function, multi-signature boost::function naturally models an overload set
Actually it is a bit more, because you can have different state for each overload. I would need something in the middle: a single polymorphic closure which can be accessed dynamically with multiple objects.
Sorry but the above sentence does not parse for me. I have to think again on what you meant, sorry, but could you better explain what you mean ? It's my fault to be dumb ;-) Thanks Marco