Data and Typeable instances

18 Apr 2009

      Jeremy Shaw wrote:
...
At Fri, 17 Apr 2009 11:55:51 -0700,
Ashley Yakeley wrote:
...
Instances of Typeable have been requested for various types. I'll add 
these for 1.1.3.
Sweet! Data as well? Happstack uses Data and Typeable for
serialization. It would be nice to be able to use Data.Time instead of
System.Time.
I'm not sure. I find the whole SYB approach unhaskellish, as it treats 
values based on their internal structure rather than their types. But 
perhaps serialisation is a harmless use of the Data class.

Typeable is also rather unhaskellish. A haskellish approach would be to 
use type witnesses, but it requires open witness declarations as a 
language extension. So, Typeable it is.

-- 
Ashley Yakeley
Seattle, WA