From 7911a8d1607b393fb1d174dbacf42b581fb368d0 Mon Sep 17 00:00:00 2001
From: Yuri Tatishchev <itatishch@gmail.com>
Date: Sat, 14 Feb 2026 18:30:31 -0800
Subject: [PATCH] lab04b: WIP

---
 lab04/lab.lhs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lab04/lab.lhs b/lab04/lab.lhs
index afb045b..58e2eb9 100644
--- a/lab04/lab.lhs
+++ b/lab04/lab.lhs
@@ -7,18 +7,22 @@ defined as myFoldl
 
 > myFoldl :: (a -> b -> a) -> a -> [b] -> a
 > myFoldl _ _ _ = error "TBD"
+> myFoldl f acc [] = acc
+> myFoldl f acc (x:xs) = f acc $ myFoldl f x xs
 
 
 Next, define a function to reverse a list using foldl.
 
 > myReverse :: [a] -> [a]
-> myReverse _ = error "TBD"
+> myReverse = foldl (\acc x -> x : acc) []
 
 
 Now define your own version of foldr, named myFoldr
 
 > myFoldr :: (a -> b -> b) -> b -> [a] -> b
 > myFoldr _ _ _ = error "TBD"
+> myFoldr f acc [] = acc
+> myFoldr f acc (x:xs) = f x $ myFoldr f acc xs
 
 
 Now try using foldl (the library version, not yours) to sum up the numbers of a large list.