At 2001-02-22 20:54, Julian Assange wrote:

Is there a standard construct for something of this ilk:

unliftM :: Monad m a -> a

Assuming you mean "unliftM :: (Monad m) => m a -> a", I certainly hope not!!!

In this case, I need to construct a localised stateful computation

comp :: Int -> Int comp n = unliftM (do x <- ... return x)

The correct way to express this is: comp :: Int -> IO Int comp n = (do x <- ... return x) I think of "IO Int" meaning "instructions for an imperative action, that, if performed, would return an Int". That's quite different from an Int. -- Ashley Yakeley, Seattle WA Almost empty page: <http://semantic.org/>