[Haskell-cafe] Serializing UTCTimes

[Bas van Dijk]

Thanks Ertugrul and Yitzchak. I failed to notice the Real and
Fractional instances for DiffTime. Thanks very much for pointing me to
it. I dropped the dependency on datetime and implemented your
suggestions.

Bas

On 21 January 2012 22:29, Yitzchak Gale <gale at sefer.org> wrote:
> Bas van Dijk wrote:
>> What's the recommended way for serializing (with the cereal package) an UTCTime?
>
> Serialize the Day part as an Integer using
> toModifiedJulianDay/ModifiedJulianDay,
> (Note that Day is not a constructor, it's just the name of
> the type.)
>
> Serialize the DiffTime as a Rational, as Ertugrul said.
>
>> I'm now using the datetime package
>
> Why? It just obscures the time library.
>
>> But I will have to look at the code of datetime to see if I'm not
>> losing precision.
>
> You are losing precision. If you only care
> about time to the nearest second, you can truncate
> the Rational of the DiffTime (don't round, because
> this may be the last second of a day) and then
> use fromIntegral to deserialize.
>
> Regards,
> Yitz