Time library underspecified

[Christopher Milton]

Hmm, this has come up before:

http://www.haskell.org/pipermail/glasgow-haskell-bugs/2001-September/001810.html
http://www.haskell.org/pipermail/haskell/2002-January/008678.html

--- Peter Thiemann <thiemann@informatik.uni-freiburg.de> wrote:
> Did anyone try to use the standard Time library that comes with Haskell 
> for a serious purpose?
> 
> I wanted to, but came across the problem that the TimeDiff data type is 
> underspecified. For example, what is the official way to convert a 
> TimeDiff value into seconds? The problematic parts are:
> * how many days for one tdYear (365, 366)
> * how many days for one tdMonth (28,29,30,31)
> * how many seconds for one tdMin (given the presence of leap seconds)^(1)
> Actually, once the absolute reference of the TimeDiff is lost, then it
> is impossible to recover leap years and leap seconds, so TimeDiff
> better had to account for them somehow. I suppose, the best would be
> to just have diffClockTimes return the number of seconds as an Integer.
> 
> Since Simon PJ has finished editing the library report, who's now in 
> charge of keeping track of problems with it and perhaps writing a 
> commentary in cases such as this?
> 
> Cheers
> -Peter
> 
> (1) for this one, there is reasonable consensus. for example the ISO 
> 8601 standard (representation of dates and times) defines minute=60 
> seconds, hour=60 minutes, day=24 hours. However, this leads to the 
> strange(?) situation that the difference between
> 1998-12-31T12:00:00 and 1999-01-01T12:00:00
> is 1 day and one second. (There was a leap second on that night
> 
>                1998 December 31   23h   59m   59s
>                1998 December 31   23h   59m   60s
>                1999 January  01    0h    0m    0s
> 
> see http://tycho.usno.navy.mil/leap.html)
> 
> 
> 
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=====
Christopher Milton
cmiltonperl@yahoo.com

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