Re: [Haskell-cafe] Typeable and fancy types

Ron Alford wrote:

instance Typeable1 f => Typeable (Expr f) where typeOf (In x) = mkTyConApp (mkTyCon "TypeTest.Expr") [typeOf1 x]

typeOf ~(In x) = mkTyConApp (mkTyCon "TypeTest.Expr") [typeOf1 x] Lazy patterns are jolly useful here. Remember that typeOf will be usually called on _|_, so it must not inspect its argument. Also, dummy functions such as getC :: Foo a b c d -> c getC _ = undefined can be exploited in typeOf x = ... typeOf (getC x) ... Zun.