[Boost-users] Boost::Date_Time - Incr and Decr Operators

Getting started with Boost::Date_Time ... It seems that this is OK: greg_year y1(2000); y1 = y1 + 1; but this is not: greg_year y1(2000); y1++; I take it that the increment and decrement operators are not implemented for greg_year (or the corresponding month, day, etc. types). Is this just incidental to the current implmentation, or is there some particular architectural or domain reason why ++ and -- aren't in the mix? - Steve