On Wed, 6 Aug 2003 10:11:20 -0700, Stephan T. Lavavej wrote > [Jeff Garland] > > The downside of this is that when you are printing a time duration: > > std::cout << td.hours() << ':' << td.minutes() << ':' << td.seconds(); > > you have to take remove the sign from the minutes and seconds. > > I have a third suggestion: > > - Implement (1) using abs() in the hours() method > > - Add a total_seconds function to the library so you don't have to write > > it. > >[Stephan T. Lavavej] > How about: > > * Implement (2), making all components negative if the time_duration > is negative * Add a total_seconds() fxn so users don't have to write > it * Allow users to lexical_cast<string> a time_duration so it can > be printed as "-5:34:22" and document this so that users don't try > to roll their own naively.
I believe to_simple_string does what you are suggesting so you shouldn't need lexical_cast. > Some unrelated issues that have come to me while working with date_time: > > * The documentation could stand some revision. There's apparently daylight > saving time stuff in the code, but it's not documented at all. Yes, the DST part of the library is under experiment and revision which is why there is a lack of documentation. > * It's also not obvious from the documentation where things like > January and Tuesday live. This applies generally; it's not obvious > what namespace many functions and classes live in. Ok. The answer is there are 3 namespaces: boost::date_time, boost::gregorian, and boost::posix_time. boost::date_time is where 'time system independent' or reuseble components live. boost::gregorian and boost::posix_time are 'instances' of a set of compatible temporal types and related classes built from the components in boost::date_time. Mostly they are comprised of typedefs of templates in boost::date_time and selection of specific implementations (eg: selecting the size integer to use for the time duration). So January ends up living in both date_time and gregorian. You can imagine needing it to build 'MyAlternativeDateSystem' and wanting the enum for the interface. > * I looked at the code and determined that Sunday = 0 (it's an > enumeration), but it'd be nice if this were guaranteed in the > documentation. Ok. > * One example shows: > last_kday_of_month lkm(Monday,Jan); > date d = lkm.get_date(2002);//2002-Jan-28 > > I found that I had to write: > first_kday_of_month<date>(Sunday, Apr).get_date(2002) This was a bug (missing typedef) that has been fixed. If you update your boost/date_time/gregorian/gregorian_types.hpp you will pick it up. > Shouldn't the fact that first_kday_of_month and its ilk are > templated be documented? I was confused why I have to template it > on date in the first place (what else would go there?). Well sure, but virtually everything in the library is a template so that isn't going to help much. If you want to see more about what is under the hood I recommend looking at: http://www.crystalclearsoftware.com/libraries/gdtl/gdtl_ref_guide/index.html or http://www.crystalclearsoftware.com/libraries/gdtl/gdtl_ref_guide/annotated.html HTH, Jeff _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
