MR K P SCHUPKE wrote:

Thanks for the URL... I have realised I jumped the gun saying the derivation can be done in template-haskell... there is one small problem:

$(derive [t| SomeConstructor a b |])

passes the constructor to derive... is there any way to get the type information for some type? You can do

$(derive [d| data X a b = X1 a b |])

Is there any way to get the same information from something like:

$(derive2 [T| X a b |])

You would have to say $(derive (reifyDecl X)) / Ulf