add fifth exercise of lecture 2

1 files changed, 17 insertions, 0 deletions

diff --git a/lec02/LogAnalysis.hs b/lec02/LogAnalysis.hs
index f71410a..6d79ca6 100644
--- a/lec02/LogAnalysis.hs
+++ b/lec02/LogAnalysis.hs
@@ -56,3 +56,20 @@ inOrder :: MessageTree -> [LogMessage]
 inOrder Leaf = []
 inOrder (Node tl m tr) = inOrder tl ++ [m] ++ inOrder tr
 
+-- Exercise 5
+
+logText :: LogMessage -> String
+logText (Unknown _) = ""
+logText (LogMessage _ _ text) = text
+
+isRelevant :: LogMessage -> Bool
+isRelevant (Unknown _) = False
+isRelevant (LogMessage (Error s) _ _)
+    | s >= 50 = True
+    | otherwise = False
+isRelevant (LogMessage _ _ _) = False
+
+whatWentWrong :: [LogMessage] -> [String]
+whatWentWrong [] = []
+whatWentWrong ((Unknown _):ms) = whatWentWrong ms
+whatWentWrong ms = map logText (filter isRelevant ((inOrder . build) ms))