No big deal after all. Replacing the ($) uses with regular parenthesized
application allows compilation to go through. - Conal
On 8/21/07, Conal Elliott <[EMAIL PROTECTED]> wrote:
>
> In going from ghc-6.6 to ghc-6.7, I've lost some GADT pattern matching
> that I'd really like to have back. The message:
>
> c:/conal/Haskell/Eros/src/gadt-example.hs :23:32:
> GADT pattern match in non-rigid context for `:*'
> Tell GHC HQ if you'd like this to unify the context
> In the pattern: a :* b
> In a lambda abstraction: \ (a :* b) -> ((f a) :* b)
> In the second argument of `($)', namely
> `\ (a :* b) -> ((f a) :* b)'
>
> and the relevant code:
>
> -- | Statically typed type representations
> data Ty :: * -> * where
> (:*) :: Ty a -> Ty b -> Ty (a, b)
> (:->) :: Ty a -> Ty b -> Ty (a->b)
> OtherTy :: TypeRep -> Ty a
>
> -- | Type transformations
> newtype TyFun a b = TyFun { unTyFun :: Ty a -> Ty b }
>
> instance Arrow TyFun where
> TyFun f >>> TyFun g = TyFun (f >>> g)
> first (TyFun f) = TyFun $ \ (a :* b) -> (f a :* b)
> second (TyFun g) = TyFun $ \ (a :* b) -> (a :* g b)
>
> Full test module attached with many more example matchings.
>
> I'd really like to get this code working in ghc-6.7. How likely is that?
> The best alternative I know is *much* less readable.
>
> Thanks, - Conal
>
>
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