On Sat, May 10, 2008 at 10:32 AM, Marco Costalba <mcostalba@gmail.com> wrote:
On Sat, May 10, 2008 at 3:17 AM, Giovanni Piero Deretta <gpderetta@gmail.com> wrote:
1) can you dispatch on the dynamic type of an object? I.e.
struct Base { virtual ~Base() {} };
struct A : Base {}; struct B : Base {};
void foo1(A&); void foo2(B&);
f = foo1; f = foo2;
A a; B b; foo((Base&)a); // calls foo1 foo((Base&)b); // calls foo2
Probably you mean
f((Base&)a); // calls foo1 f((Base&)b); // calls foo2
Anyway no you can't. But because also boost::function can't I fail to see an inconsistency. Indeed
boost::function<int(A&)> f= foo1;
f((Base&)a); // calls foo1 <---- COMPILER ERROR: cannot convert parameter 1 from Base to A&
Ok. I know that boost function can't do it, but I thought that dynamic dispatching would come easier once you had multiple overload dispatching functionality. Thinking of it, it probably needs registering all derived types of Base. Anyways I do not think that MSF should provide this, it was just a whish :)
2) If I have a polymorphic function object, can I store a single instance of this object and specify multiple signatures? i.e.
struct foo_t { template<class T> void(T){...} } foo;
Sorry but the line
struct foo_t { template<class T> void(T){} } foo;
does not compile for me. Probably I'm missing something obvious.
I'll reply to this in another email. -- gpd