Mathias, On Sun, Mar 29, 2009 at 7:01 PM, Mathias Gaunard < mathias.gaunard@ens-lyon.org> wrote:
- Allow the easy construction of a visitor from lambda expressions, with a syntax like
variant<int, std::string> a = "foo";
int b = match(a).with( args<int>(_1), args<std::string>(size(_1)) );
instead of the potentially more verbose
struct my_visitor : static_visitor<int> { int operator()(int a) { return a; } int operator()(const std::string& b) { return b.size(); } };
variant<int, std::string> a = "foo";;
int b = apply_visitor(my_visitor(), a);
You may find this useful: https://svn.boost.org/svn/boost/sandbox/boost/type_switch.hpp http://lists.boost.org/Archives/boost/2003/10/54774.php I had started on it some years ago, but never followed through. It has some cool features, though, like pattern matching: using namespace boost::type_switch; variant< int , pair<int,double> , pair<int,int> , pair<double,int> > var; switch_(var) |= case_< pair<_1,_1> >(...) // matches pair<int,int> |= case_< pair<int,_> >(...) // matches pair<int,*> |= case_< pair<_,_> >(...) // matches pair<*,*> |= case_< int >(...) ; Eric