AMDG Zachary Turner wrote:
Suppose I've got a bunch of different classes that all support a common compile-time interface. In other words, a bunch of different classes, each of which has N methods with identical names and signatures but no common base class.
I want to make a variant out of all these types, and in addition I want to allow visititation to all of the common methods.
Currently I have defined a separate static_visitor derived class for every common method, but this is a little bit annoying. For example, I have currently something like this:
struct Foo1 { void f(int); void g(double); void h(string); };
struct Foo2 { void f(int); //Common method void g(double); //Common method void h(float); //Not a common method };
struct visit_f : public boost::static_visitor<> { template<typename T> void operator()(T& t, int i) const { t.f(i); } };
struct visit_g : public boost::static_visitor<> { template<typename T> void operator()(T& t, double d) const { t.g(d); } };
What would be the suggested way of making this more generic, so that I need not have a separate visitor for every method?
I don't think that there's a good way except to use a macro. #define FORWARDING_VISITOR(function) \ struct visit_ ## function : public boost::static_visitor<>\ {\ template<class T0, class T1>\ void operator()(T0& t0, T1& t1) const {\ t0.function(t1);\ }\ } FORWARDING_VISITOR(f); FORWARDING_VISITOR(g); In Christ, Steven Watanabe