Your examples are equivalent to set operations on an ordinary real number line.> The boost Math library doesn't seem to implement this. Anyway, I think that> this what you're asking for should be made into a general-purpose utility, and> not something specific to the date_time library.> Why is subtraction of periods less "specific to the date_time library", than the following functions? contains() intersects() intersection() shift() expand() merge() span()
Subtraction of intervals seems to be very "native" operation for time_period, since it's VERY common task when working with time intervals. For example: one of my classes evaluates requests expressed in terms time_period. Each request is expensive, so the implementation "caches" them: say, if a user had already issued the request for period1:[1..8) and now he requested period2:[5..15), the evaluation must take place for [8-15) only... _________________________________________________________________ Connect to the next generation of MSN Messenger http://imagine-msn.com/messenger/launch80/default.aspx?locale=en-us&source=wlmailtagline