Re: [Haskell-cafe] A pattern type signature cannot bind scoped type variables `t'

On Mon, 2009-01-12 at 20:24 -0200, rodrigo.bonifacio wrote:

Hi all,

I'm trying to build a library that has the following code:

hasTypeOf (TermRep (dx,_,_)) (x::t) = ((fromDynamic dx)::Maybe t)

Could you do something like this? Enforce the types with a signature: hasTypeOf :: (Typeable t) => Dynamic -> t -> Maybe t hasTypeOf x _ = fromDynamic x

hasTypeOf (toDyn (2::Int)) (undefined::Integer) Nothing hasTypeOf (toDyn (2::Int)) (undefined::Int) Just 2

Or if you just want boolean result: hasTypeOf x y = typeOf y == dynTypeRep x