ex8, whileRight done

exercises/Set3a.hs

@@ -169,7 +169,9 @@ while check update value = if check value then while check update (update value)
 -- Hint! Remember the case-of expression from lecture 2.
 
 whileRight :: (a -> Either b a) -> a -> b
-whileRight check x = todo
+whileRight check x = case check x of 
+    Left value -> value
+    Right x -> whileRight check x
 
 -- for the whileRight examples:
 -- step k x doubles x if it's less than k