Data.Fixed (in base) has been updated with Data instances in HEAD. When that's released, I'll release time-extra that will contain Data instances. I've got it all ready to go.
The reason Data instances are in time-extras is that the time library must be Haskell 98, while Data instances require Rank2. -- Ashley On Wed, 2009-10-21 at 11:15 -0500, Thomas Hartman wrote: > update: > > on haskell reddit, dons suggested simply patching time. reasonable > enough, but I hit a glitch where the Data.Fixed (in base lib) was > missing a Data instance, and gave up when I couldn't find the source > repo for base. Is this simply part of ghc? > > Anyways, that instance seems to be added in ghc 6.12 so probably a non > issue now or closer to it. > > http://www.haskell.org/ghc/dist/current/docs/html/libraries/base/Data-Fixed.html > > also, aavogton #haskell suggested > > http://hpaste.org/fastcgi/hpaste.fcgi/view?id=11009#a11009 > > as a workaround for people using time on happstack earlier than 6.12, > probably nicer than the MyTime hack I created though it comes with a > bit more baggage. > > I haven't upgraded to 6.12 but I would suggest that time now be made > Data Generics friendly if it hasn't already, since this is probably a > very simple change and would be helpful to happstack. If no one has > time to do this I'll try to get around to it when I upgrade to 6.12. > > Also wouter swierstra suggested that standalone deriving ( > http://www.haskell.org/ghc/docs/latest/html/users_guide/deriving.html#stand-alone-deriving > ) could be helpful in this case but I'm not sure why, or even whether > this was for data-izing data.time or system.time or both. > > Given all this I won't be uploading anything to hackage, and hopefully > the base libs + time will be data friendly soon enough. > > thomas. > > 2009/10/19 Thomas Hartman <tphya...@gmail.com>: > > At > > > > http://osdir.com/ml/haskell-cafe@haskell.org/2009-10/msg00197.html > > > > I griped that the lack of Data-Derivable time values was causing me > > headache in happstack. > > > > In the proposed cabal package > > > > http://patch-tag.com/r/tphyahoo/systemtimetypeable/snapshot/current/content/pretty/systemtimetypeable.cabal > > > > I submit a workaround that, while probably not the ideal thing, has > > proved helpful to me. > > > > Basically, I use the type MyTime, which is data-deriveable, when > > working with Macid in happstack; and convert from System.Time and/or > > Data.Time with the accompanying utility functions when necessary. > > Perhaps the utility functions are useful on their own as well. I found > > it surprisingly hard to get from Data.Time values to System.Time > > values. > > > > Anyways, I am interested in what others think and, of course, patches > > and suggestions welcome. > > > > thomas. > > > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe