Zip resuelto sin recursividad

zip.hs

zip''::[a]->[b]->[(a,b)]
zip'' = foldr group (\_ -> [])
	where 
		group x f (y:ys)  = (x,y):(f ys)
		group _ _ []  = []

zip'::[a]->[b]->[(a,b)]
zip' l1 = snd.foldl sarasa (l1,[])
	where
		sarasa ([],acum) _ = ([],acum)
		sarasa ((x:xs),acum) y = (xs,(x,y):acum)