Hello, I've been using the Boost.PP lately, and everything now works rather nicely, but there's been a thing in the back of my head that has always been telling me, that the problem is better suited to mpl/fusion. The problem in this case is I have "two things" that need to be iterated over, one a series of tags (aka "types"), and the the other, a runtime index. I'll express what I'm after with mpl::for_each, because the issue becomes clearer that way: using namespace boost; //Func: is an object that facilitates visitation on algorithms template