Utils: iterateN: upd docs

Author: Anton-Latukha

src/Nix/Utils.hs

@@ -325,9 +325,13 @@ traverseM
   -> m (f (t b))
 traverseM f x = sequenceA <$> traverse f x
 
--- | Apply a function @n@ times to a given value.
-iterateN :: Int -> (a -> a) -> a -> a
-iterateN n f x = fix ((<*> (0 /=)) . ((bool x . f) .) . (. pred)) $ n -- It is hard to read - yes. It is a single action without recursion - yes.
+iterateN
+  :: forall a
+   . Int -- ^ times
+  -> (a -> a) -- ^ function apply
+  -> a -- ^ on value
+  -> a
+iterateN n f x = fix ((<*> (0 /=)) . ((bool x . f) .) . (. pred)) n -- It is hard to read - yes. It is a non-recursive momoized action - yes.
 
 -- | Apply Kleisli arrow N times, join 'm's.
 nestM :: Monad m => Int -> (a -> m a) -> a -> m a