other implementations. If you post your benchmark, I could actually make a comparison.
Attaching the test program along with both versions of the product_view<>. I used the following [bash] commands to benchmark it:
for n in 1 2 3 4 5 6 7 8 9; do time g++-4.2 -DCOUNT=$n test_product_view.cpp; done
and
for n in 1 2 3 4 5 6 7 ; do time g++-4.2 -DCOUNT=$n -DRECURSIVE test_product_view.cpp; done
Note that both my versions produce flattened view (a sequence of tuples which are sequences of the same kind as the top-level sequence of the argument). Whether the flattened or the nested representations are more correct is, of course, a philosophical question -- but I originally needed the flattened view for my particular application. Regards, ...Max...