RE: Time Resolution

On 02 February 2005 07:25, Ashley Yakeley wrote:

In article , Ashley Yakeley wrote:

...

It looks like we may need three types here:

* one for TAI

* one for POSIX time, which is a broken encoding of UTC

* one for correct encoding of UTC

This is the sort of thing I mean:

newtype TAITime = TAITime Integer deriving (...)

newtype POSIXTime = POSIXTime Integer deriving (...)

newtype DiffTime = DiffTime Integer deriving (...)

type JulianDay = Integer

data UTCTime = UTCTime JulianDay DiffTime

getCurrentTime :: IO POSIXTime

posixToUTCTime :: POSIXTime -> UTCTime

Why does the user of the library care about the difference between UTC, TAI and POSIX time? The only way I can think that this really needs to be exposed to the programmer is so that they can tell the library whether the system clock is running POSIX or TAI time. For the library API, a single notion of time is sufficient, no? Cheers, Simon