Control.Monad.Signatures

Signatures for monad operations that require specialized lifting. Each signature has a uniformity property that the lifting should satisfy.

Documentation

type CallCC m a b = ((a -> m b) -> m a) -> m a

Signature of the callCC operation, introduced in Control.Monad.Trans.Cont. Any lifting function liftCallCC should satisfy

• lift (f k) = f' (lift . k) => lift (cf f) = liftCallCC cf f'

type Catch e m a = m a -> (e -> m a) -> m a

Signature of the catchE operation, introduced in Control.Monad.Trans.Except. Any lifting function liftCatch should satisfy

• lift (cf m f) = liftCatch (lift . cf) (lift f)

type Listen w m a = m a -> m (a, w)

Signature of the listen operation, introduced in Control.Monad.Trans.Writer. Any lifting function liftListen should satisfy

• lift . liftListen = liftListen . lift

type Pass w m a = m (a, w -> w) -> m a

Signature of the pass operation, introduced in Control.Monad.Trans.Writer. Any lifting function liftPass should satisfy

• lift . liftPass = liftPass . lift