21 Oct
2004
21 Oct
'04
8:15 p.m.
On Sat, Oct 16, 2004 at 05:54:46AM +0000, oleg@pobox.com wrote:
data Bar a m = forall t. (MonadTrans t, Monad (t m)) => Bar (t m a -> m a) (t m Int)
data Foo = Foo (forall a m. Monad m => Bar a m)
Is it true that I cannot have a function foo run op = Foo (Bar run op) because it does not have an expressible type? Or is there some way to make ghc accept this? Obviously, this expression can be used in the context of a larger expression.
myFoo :: Int -> Foo myFoo i = Foo (Bar run op) where run :: Monad m => StateT Int m a -> m a run prog = do (a, s) <- runStateT prog i return a op :: Monad m => StateT Int m Int op = get
Andrew