add second exercise of lecture 8

1 files changed, 6 insertions, 0 deletions

diff --git a/lec08/Party.hs b/lec08/Party.hs
index fe60fe8..05b5e0e 100644
--- a/lec08/Party.hs
+++ b/lec08/Party.hs
@@ -1,6 +1,7 @@
 module Party where
 
 import Employee
+import Data.Tree
 
 -- Exercise 1
 
@@ -18,3 +19,8 @@ moreFun :: GuestList -> GuestList -> GuestList
 moreFun gl1@(GL _ f1) gl2@(GL _ f2)
   | f1 >= f2  = gl1
   | otherwise = gl2
+
+-- Exercise 2
+
+treeFold :: (a -> [b] -> b) -> Tree a -> b
+treeFold f (Node l subs) = f l $ map (\t -> treeFold f t) subs