takeWhile package:pipes

takeWhile :: Functor m => (a -> Bool) -> Pipe a a m ()
pipes Pipes.Prelude
(takeWhile p) allows values to pass downstream so long as they satisfy the predicate p. 
takeWhile (pure True) = cat

takeWhile (liftA2 (&&) p1 p2) = takeWhile p1 >-> takeWhile p2
takeWhile' :: Functor m => (a -> Bool) -> Pipe a a m a
pipes Pipes.Prelude
(takeWhile' p) is a version of takeWhile that returns the value failing the predicate. 
takeWhile' (pure True) = cat

takeWhile' (liftA2 (&&) p1 p2) = takeWhile' p1 >-> takeWhile' p2