Once Tropical Storm Jeanne passes away, I should be through with hurricanes for a while. The latest-and-greatest MPL looks great! The new ability to plug in custom numeric metatypes so that they work with existing numeric ops makes it a definite keeper. The part of my sub-library that I've updated to work with the new MPL is at <http://groups.yahoo.com/group/boost/files/mpl_math.zip>, and has been tested with MinGW 3.2 and MSVC 7.1 (2003 Toolkit). Renaming issues aren't too bad; I just have to remember (for one thing) that reverse_copy is defined at copy.hpp and not reverse_copy.hpp as I originally thought. I also noticed that BOOST_MPL_AUX_TYPEOF is no longer there, but I've managed to eliminate the need for it. A major issue I have is how to properly use numeric_cast in order to make something like the following statement work correctly: typedef plus<int_<1>,fraction_c<long,4,3> >::type fraction_7_over_3; Right now I've made N^2 specializations of plus_impl, where N here means the total number of built-in and custom numeric metatypes. For my sub-library, N==4, which means I've made 16 specializations of plus_impl alone! Factor in the comparison ops as well the arithmetic ops, and my code is starting to look bloated. I've supplied a couple of convenience macros to reduce the copy-and-pasting, but I still think I'm missing something crucial here, and I think that something is how to use (or specialize) numeric_cast. Pointers welcome! Cromwell Enage __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage! http://promotions.yahoo.com/new_mail