From d670cedeb7e4c62ea893d138ee3b130a0828d7e2 Mon Sep 17 00:00:00 2001 From: Joel Kaasinen Date: Fri, 26 Sep 2025 09:53:48 +0300 Subject: [PATCH] lecture 16: fix QuickCheck rev example closes #111 --- exercises/Examples/QuickCheck.hs | 4 ++-- part2.html | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/exercises/Examples/QuickCheck.hs b/exercises/Examples/QuickCheck.hs index 4e82bf8..d28d751 100644 --- a/exercises/Examples/QuickCheck.hs +++ b/exercises/Examples/QuickCheck.hs @@ -5,8 +5,8 @@ import Data.Char import Data.List rev :: [a] -> [a] -rev [] = [] -rev (x:xs) = xs ++ [x] +rev (x:y:xs) = y:x:xs +rev xs = xs propRevSmall :: Property propRevSmall = rev [1,2] === [2,1] diff --git a/part2.html b/part2.html index 193690a..ab98d97 100644 --- a/part2.html +++ b/part2.html @@ -6329,8 +6329,8 @@ the file exercises/Examples/QuickCheck.hs.

rev :: [a] -> [a]
-rev [] = []
-rev (x:xs) = xs ++ [x]
+rev (x:y:xs) = y:x:xs +rev xs = xs

We can write an individual test case using the === operator from QuickCheck: