withReader

withReader :: (r' -> r) -> Reader r a -> Reader r' a
transformers Control.Monad.Trans.Reader, mtl Control.Monad.Reader
Execute a computation in a modified environment (a specialization of withReaderT). *  (withReader f m) = runReader m > .
withReaderT :: (r' -> r) -> ReaderT r m a -> ReaderT r' m a
transformers Control.Monad.Trans.Reader, mtl Control.Monad.Reader
Execute a computation in a modified environment (a more general version of local). *  (withReaderT f m) = > runReaderT m .