ANN: time-1.4.0.1

[Ashley Yakeley]

Now on Hackage, version 1.4.0.1 of time includes the rewrite RULES 
provided by Liyang HU.

-- Ashley

On 25/09/11 03:12, Liyang HU wrote:
> Hi,
>
> The time package is too slow. :(
>
> A prime example is diffUTCTime, which invokes utcTimeToPOSIXSeconds,
> which in turn calls realToFrac :: DiffTime ->  NominalDiffTime. The
> former of these two types notionally accounts for leap seconds, while
> the latter does not. Both are newtypes around Data.Fixed.Pico.
>
> Since realToFrac is used in the library only when we know the
> difference is within one day, the two notions coincide, and there is
> no need to account for leap seconds. Indeed it currently (or rather,
> its implementation of "fromRational . toRational") behaves as such.
>
> I propose we include some rewrite RULES to eliminate the round-trip
> via Rational. For the attached benchmark, I get a ~4x improvement in
> speed.
>
> Discussion period: 2 weeks.
>
> Cheers,
> /Liyang