Hi, Here some question I've got while reading submitted library. 1. What is an advantage if using this library for scalar types (vs. defining operator<<) 2. If primary target is collection formatting wouldn't it be better to name library "collection formats something"? 3. If there is a way to assign format to collection/type combination permanently (through global operator <<), why would I want to do it in every instance of output operation? 4. What is an advantage of using this library to assign format to collection/type combination permanently vs. explicit implementation (using FOREACH construct for example) 5. Why do we need boost::io::range? Couldn't we use boost::range instead? 6. In a formatter usage how would I guess what is what? boost::io::formatter< char * > fmt( "\ ", " /", " | " ); boost::io::formatob( vec, boost::io::containerfmt()).format( fmt ); 7. Who come format calls order dependent? boost::io::formatob( vec, boost::io::containerfmt()).format( fmt ).format( " : " ); 8. If I got vector<vector<int> >. How do I supply separators for both internal and external vectors? 9. Let say I print vector<char>. Is there way to print it like this: { 'a', 'b', '0x01', ' ' } That's enough for now. Please comment. Gennadiy.