Time library underspecified

[Lennart Augustsson]

Yes, I totally agree.  The current time library is pretty broken.

    -- Lennart

John Meacham wrote:

>yes! I was just wrestling with this yesterday. I finally gave up and
>looked inside ghc's (TOD Integer Integer) directly because the Time
>library as it currently stands is somewhat less than useful. This is
>probably a pretty serious bug in Haskell 98 as there is no good way to
>work with times other than roll your own.
>
>how about:
>toRawTime :: ClockTime -> (Integer,Integer)
>where they are # of seconds and picoseconds since epoch.
>(and an 'epoch' constant ClockTime)
>
>another useful thing would be  
>endOfTime and beginningOfTime constants, representing the minimum and
>maximum values representable by ClockTime.
>	John
>
>On Thu, Nov 14, 2002 at 10:22:46AM -0800, Christopher Milton wrote:
>  
>
>>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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>>
>
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