On 3/27/06, lee marks [EMAIL PROTECTED] wrote:
So this is legal:
type Fix s a = s a (Fix s a)
fold :: Functor (s a) = (s a b - b) - Fix s a - b
fold f = f . fmap (fold f)
but this is not:
fold f = f . fmap (fold f)
data Fix s a = Fix {runFix :: s a (Fix s a)}
fold :: Functor (s
John Hughes wrote:
...
Indeed, error messages in common cases would be worsened significantly,
because as Ross says, common errors (such as forgetting a parameter in a
recursive call) would lead to legal definitions that cause a type error
when applied. Partly for this reason, OCaml
