Is it possible to iterate an mpl::vector at run time without instantiating the types in the vector?

Question

Generally, I would use boost::mpl::for_each<>() to traverse a boost::mpl::vector, but this requires a functor with a template function declar

Answer 1

Well, first of all, the static call in your code means that your object will exist. Before/after is meaningless in that regard. The only time, "I don't want T to be instantiated at all prior to the call," make sense is when T is a template. It's not, because it can't be. It is true that it is that line that causes the object to exist, but I am pretty sure it won't just exist there once the product is compiled.

Second of all, I don't believe that there's a current method to use for_each without instantiating. IMHO this is a bug in MPL caused by a questionable decision to use operator(). Won't say it's wrong since I know the developer and he's a lot smarter than I am, but it seems so from here now that you bring this up.

So, I think you're stuck having to remake a for_each that calls a templated function that doesn't require the parameter. I'm almost certain it is possible, but also equally certain it's not readily available as a premade component in MPL.