Hi, Oven, an implementation of the Range Library Proposal, was uploaded to Vault/Algorithms. I suppose it is considered as Boost.View2 or range_ex2. The file: http://tinyurl.com/2axp2l Range Library Proposal: http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1871.html An example "lazy merge sort": typedef any_range<int const&, boost::forward_traversal_tag> range; range merge_sort(range rng) { typedef boost::result_of<op_distance(range&)>::type diff_t; diff_t d = distance(rng); if (d < 2) return rng; else { return make_merged( merge_sort(rng|taken(d/2)), merge_sort(rng|dropped(d/2)) ); } } The status is highly preliminary, but moderately tested. Any feedback appreciated. Regards, -- Shunsuke Sogame