You seem to be replacing the sequence of catch-es (which is order-specific), with overloading (which isn't). The order is important, because in a way each catch is a more generic fallback for the previous ones. --Emil Jeremy Day wrote:
All,
A message a few days ago, along with my current reading of the book 'C++ Template Metaprogramming', piqued my interest in the idea of an "exception visitor". I put together a little something, and I'm wondering if people might be interested in my (rather poor, at the moment) code.
Problem:
When using exceptions it is very easy to end up with code that looks something like this:
try { //Some code that might throw exceptions. } catch(std::logic_error&) { //Handle the exception. } catch(std::exception&) { //Handle exception. } catch(...) { //Handle everything else }
With my code you can transform the above into something along these lines:
struct my_exception_handler { typedef boost::mpl::vector<std::logic_error, std::exception> exceptions;
void operator()(std::exception& oError) { std::cout << "my_exception_handler::operator()(std::exception&)" << std::endl; }
void operator()(std::logic_error& oError) { std::cout << "my_exception_handler::operator()(std::logic_error&)" << std::endl; }
void operator()(void) { std::cout << "my_exception_handler::operator()(void)" << std::endl; } };
//Application code.
try { //Some code that might throw exceptions, such as: throw std::logic_error("A sample logic error."); } catch(...) { //Magic happens here. catcher(my_exception_handler()); //This prints out "my_exception_handler::operator()(std::logic_error&)" }
If anyone is interested I will post what I have for critique (I'm a relative newbie with MPL, so I will likely need a lot of help). I look forward to any and all comments.
Jeremy _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost