hi, here's what i'd like to do A] hpp: struct my{ template<typename ArgPack> my(const ArgPack& args):n_(args[tag::n]),k_(args[tag::k]){} } struct argpack{ arglist<???> operator()(const string& str){???} } cpp: string str("n=2; k=1"); my(argpack(str)); In words,I'm looking to construct an ArgPack from a string, what's the appropriate library for this? Does it seem like I should invest in Boost Spirit? B] The above is a simplified version of what i really need, which is, potentially, 1) having to construct a large number of objects (to be pushed at the back of a container) 2) each object taking a large number arguments (not just n and k as above) 3) each object an instance of one of a set of classes (my0,my1,my2,...,myN) each with its specific argument tags (keywords). So I'd like to put all these arguments in a file, each line corresponding to an object, rather than have a messy cpp file. this is all very open-ended, but so reads the subject title... thanks!