24 Mar
2007
24 Mar
'07
1:30 a.m.
Hello Martin, Friday, March 23, 2007, 11:37:16 PM, you wrote:
readValue' :: Field -> Maybe (forall s. SqlBind s => s) -> Value
Thank you very much, that's exactly what I wanted. After reading in the GHC users guide about rank 2 polymorphism I thought that this is not possible. Chapter "7.4.8. Arbitrary-rank polymorphism" says:
"impredicative polymorphism" is new in ghc 6.6. look for this word in ghc docs and in spj's papers -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com