Steve Johns wrote:

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).

Right.

Is this just incidental to the current implmentation, or is there some particular architectural or domain reason why ++ and -- aren't in the mix?

Most users don't use greg_year much so it's never really come up. That said, there would be some issues. We'd need to specify this for greg_month to be symmetric. So what would we do with this: greg_month m(12); m++; //wrap? greg_year y(9999); //max year y++; //exception I would guess? So, the bottom line is that these ops aren't supported to try and keep the interface smaller. And, in general, increment and decrement require a large amount of context that isn't necessarily obvious it was a good idea. BTW, are aware that you can do this? date d(....); years y(1); y += years(2); d += y; d += week(20); Jeff