Dear all, I am not sure which version of tuples is actual and should be used: -The version in boost/tuple is working and seems consitent to the manual on the boost homepage. -The version in boost/spirit/fusion/sequence is working too and seems to be consistent to "C++ Standard Library Technical Report". tuple_size and tuple_element exist, which do not exist in the first version. Why are there two versions? Which one shall I use? Any recommendations? Thank you, Patrick P.S.: I have another short question, and need a small hint (what to search ;) ) for kind of a "compile time for-loop". Something like this: index[0] = fw_index::template get_index< tuples::tuple_element< 0, TTuple>::type >(); index[1] = fw_index::template get_index< tuples::tuple_element< 1, TTuple>::type >(); ...