On Tue, 11 Nov 2003 12:44:59 -0000
"Simon Marlow"
This has been demonstrated - recently by Juanma Barranquero's library posted to the Haskell list,
I think you're referring to Stefan Karrmann's library. I just did a couple comments about it.
Personally I think it's ok to have a library that "does its best" to give you the correct TAI time, with documented caveats. IIRC, this is where we got stuck.
FWIW, after taking a look to Stefan's Tai.lhs, I think it is interesting but way too complex. Many languages make do with things more or less equivalent to the following (ripped from the Time::Piece Perl module, which implements an interface outlined by Larry Wall time ago): $t->sec # also available as $t->second $t->min # also available as $t->minute $t->hour # 24 hour $t->mday # also available as $t->day_of_month $t->mon # 1 = January $t->_mon # 0 = January $t->monname # Feb $t->month # same as $t->monname $t->fullmonth # February $t->year # based at 0 (year 0 AD is, of course 1 BC) $t->_year # year minus 1900 $t->yy # 2 digit year $t->wday # 1 = Sunday $t->_wday # 0 = Sunday $t->day_of_week # 0 = Sunday $t->wdayname # Tue $t->day # same as wdayname $t->fullday # Tuesday $t->yday # also available as $t->day_of_year, 0 = Jan 01 $t->isdst # also available as $t->daylight_savings $t->hms # 12:34:56 $t->hms(".") # 12.34.56 $t->time # same as $t->hms $t->ymd # 2000-02-29 $t->date # same as $t->ymd $t->mdy # 02-29-2000 $t->mdy("/") # 02/29/2000 $t->dmy # 29-02-2000 $t->dmy(".") # 29.02.2000 $t->datetime # 2000-02-29T12:34:56 (ISO 8601) $t->cdate # Tue Feb 29 12:34:56 2000 "$t" # same as $t->cdate $t->epoch # seconds since the epoch $t->tzoffset # timezone offset in a Time::Seconds object $t->julian_day # number of days since Julian period began $t->mjd # modified Julian date (JD-2400000.5 days) $t->week # week number (ISO 8601) $t->is_leap_year # true if it its $t->month_last_day # 28-31 $t->time_separator($s) # set the default separator (default ":") $t->date_separator($s) # set the default separator (default "-") $t->day_list(@days) # set the default weekdays $t->mon_list(@days) # set the default months $t->strftime(FORMAT) # same as POSIX::strftime (without the overhead # of the full POSIX extension) $t->strftime() # "Tue, 29 Feb 2000 12:34:56 GMT" Time::Piece->strptime(STRING, FORMAT) # see strptime man page. Creates a new # Time::Piece object and even that could be reduced considerably. IMHO, Haskell should have a simple module which allowed to manipulate dates and times in UTC (and convert to/from localtimes, and perhaps MJD/JD), and, as an extension, a TAI module for the (probably very few) people who needs that kind of precision. I know that I've been programming quite a few years and I've never needed to know TAI times, nor ignoring the leap seconds have been a problem. And, till very recently, I was working for a VoIP carrier, so you can bet we manipulated dates, times and durations *constantly*. I'm not saying there aren't problem domains where that level of precision is required. Just they're not that common, I think. Juanma