21 Nov
2006
21 Nov
'06
10:11 a.m.
On 20/11/06, Simon Marlow
* cast that changes a phantom type, or changes a type that is not reflected by a part of the value, eg. 'unsafeCoerce (Left 3) :: Either Int a' should be fine for any 'a',
Couldn't we have the following for this case? castEitherL :: Either a b -> Either a c castEitherL (Left x) = Left x castEitherL z = z castEitherR :: Either a b -> Either c b castEitherR (Right x) = Right x castEitherR z = z Not general, but it'd work in this case. And no need for unsafeCoerce. -- -David House, dmhouse@gmail.com