[Haskell-cafe] systemtimmetypeable: Workaround for lack of deriveable data instance in either System.Time or Data.Time.

Thomas Hartman tphyahoo at gmail.com
Mon Oct 19 17:00:36 EDT 2009


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.


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