"Pavel Vozenilek" <pavel_vozenilek@hotmail.com> wrote in message news:c6s7rh$fc9$1@sea.gmane.org... | I wonder whether Collection Traits can also use Filter Iterator | (http://www.boost.org/libs/iterator/doc/filter_iterator.html) | as 'collection'. nope. The requierement is that a default constructed iterator denotes the end. | Or even whether it can simplify use of Filter Iterator a bit. I think the key for simpler use of all of the iterators in Boost.Iterator is to define special range versions of make_XX. I hope John and Matthew will do this in their range lib. For example make_filter_range( is_positive_number(), coll ); Using Collection Traits that should be simple. So eventually we can write std::copy( boost::make_filter_range( is_positive_number(), numbers ), std::ostream_iterator<int>( std::cout, " " ) ) instead of std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N), boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N), std::ostream_iterator<int>(std::cout, " ")); Ans similar for other iterators. br Thorsten