mapReader

mapReader :: (a -> b) -> Reader r a -> Reader r b
transformers Control.Monad.Trans.Reader, mtl Control.Monad.Reader
Transform the value returned by a Reader. *  (mapReader f m) = f . > runReader
mapReaderT :: (m a -> n b) -> ReaderT r m a -> ReaderT r n b
transformers Control.Monad.Trans.Reader, mtl Control.Monad.Reader
Transform the computation inside a ReaderT. *  (mapReaderT f m) = f . > runReaderT