On 01/04/2005 11:52 AM, christopher diggins wrote: [snip]
The advantages (and my motivation for creating it) of the union-list is that it requires no other boost libraries and has a very tiny code base. Another difference ( but not neccessarily an advantage ) of the union-list is that it uses and provides an index to access the type of its contents. These same advantages (AFAICT) are provided by the code reference by:
http://thread.gmane.org/gmane.comp.lib.boost.devel/115072 More specifically, by the sum.hpp code. In addition, that code shares almost the same code with product.hpp and doesn't use any extra memory. I'm still developing the code and the successors are in the same indexed_types directory in files: composite_sum composite_product However, as you can see by the above thread, there's some question about the advantages vs. the existing boost tuple and variant types. So for, I can't see how there could be since the memory is minimal and access time (AFAICT) can't be much faster since accesses are simply done by directly naming the supertype (via the Index template argument) containing the required tuple or variant member. My understanding is that Joel will answer the question when he has the time.