-- originally did:
-- filt _ [] = []
-- filt p (x:xs) = if p x then x : filt p xs else filt p xs

-- not used, but cool
map' :: (a -> b) -> [a] -> [b]
map' f = foldr ((:) . f) []
map' :: (a -> b) -> [a] -> [b]
map' f = foldr ((:) . f) []
map' f = foldr ((:) . f) []