[exercise] 7.6

Author: Dev-XYS

chapter07-High-order-functions/6.hs

@@ -0,0 +1,16 @@
+import Data.Char
+
+type Bit = Int
+
+unfold :: (a -> Bool) -> (a -> b) -> (a -> a) -> a -> [b]
+unfold p h t x | p x = []
+ | otherwise = h x : unfold p h t (t x)
+
+chop8 :: [Bit] -> [[Bit]]
+chop8 = unfold null (take 8) (drop 8)
+
+map :: (a -> b) -> [a] -> [b]
+map f = unfold null (f . head) tail
+
+iterate :: (a -> a) -> a -> [a]
+iterate f = unfold (const True) id f