Re: Old code broken by new Typeable class

5 Aug 2014

      Am Dienstag, 5. August 2014, 13:59:26 schrieb Brandon Allbery:
...
On Tue, Aug 5, 2014 at 1:47 PM, Volker Wysk 
...
So you need to be able to change the definition of the data type, in order
to
add deriving (Typeable). It's not possible to add a Typeable instance
declaration later.
Are you sure? There is a standalone deriving syntax.
deriving instance Typeable ProcessStatus
Yes, that's the solution. 

You need these options for GHC: -XStandaloneDeriving -XDeriveDataTypeable

Thanks, and Bye,
V.W.