Hi Everyone, I'm not sure if the title makes sense, but I have a problem which can be solved with a handful of preprocessor macros, but would like to see solved with Fusion. Let's say I have a vector of values: fusion::vector<int, int, int, int> ints(0, 1, 2, 3); I then have a function such as: struct function { void operator()(int value) { if (value < 2) throw runtime_error("less than 3"); cout << value << endl; }; }; Would there be a way for me to iterate through every element of 'ints' and apply the function object instance to each element, and stop the iteration only when function does not throw? I know using exceptions for control flow is pretty frowned upon, and I can certainly use it the other way around -- to short-circuit the iteration only when it throws. If you're interested in the use case for this particular question, I'm looking for a way to make the dispatcher library I'm working on (http://dispatcher.sourceforge.net/) be able to generically support the following construct: dispatcher<void(int)> d; d[2] = function(); invoke_(d)(10) << alt_(0, 1, 2, 3, 4); alt_ currently returns a homogeneous tuple (if there's such a thing). The invoker then should be able to try d[0](10) first, and since d[0] does not map to a function, it should then try d[1](10) -- which also isn't valid because d[1] is not defined -- until it gets to d[2](10), which should perform the operation, and then effectively not deal with 3 and 4 anymore. d[0](10) and d[1](10) will throw an exception of invalid_index -- currently, the implementation is hand coded to the effect of: try { d[get<0>(tuple)](arg1); } catch (invalid_index &) { d[get<1>(tuple)](arg1); } So the more indexes to check, the deeper the try { } catch (...) { } nesting goes -- which I know can be automated with a preprocessor, but I'm exploring other possibilities this time using Fusion. Pointers would be greatly appreciated. Thanks in advance! -- Dean Michael C. Berris Software Engineer, Friendster, Inc. [http://cplusplus-soup.blogspot.com/] [mikhailberis@gmail.com] [+63 928 7291459] [+1 408 4049523]