From c4cf3b0be2606b144d5646ef4f5fc295cab1e877 Mon Sep 17 00:00:00 2001
From: Jan Sucan <jan@jansucan.com>
Date: Sun, 31 Aug 2025 16:25:47 +0200
Subject: 18_a_1: Add missing module CountEntries from the examples

---
 ch18/CountEntries.hs | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)
 create mode 100644 ch18/CountEntries.hs

(limited to 'ch18/CountEntries.hs')

diff --git a/ch18/CountEntries.hs b/ch18/CountEntries.hs
new file mode 100644
index 0000000..706bec2
--- /dev/null
+++ b/ch18/CountEntries.hs
@@ -0,0 +1,22 @@
+{-- snippet countEntriesTrad --}
+module CountEntries (listDirectory, countEntriesTrad) where
+
+import System.Directory (doesDirectoryExist, getDirectoryContents)
+import System.FilePath ((</>))
+import Control.Monad (forM, liftM)
+
+listDirectory :: FilePath -> IO [String]
+listDirectory = liftM (filter notDots) . getDirectoryContents
+    where notDots p = p /= "." && p /= ".."
+
+countEntriesTrad :: FilePath -> IO [(FilePath, Int)]
+countEntriesTrad path = do
+  contents <- listDirectory path
+  rest <- forM contents $ \name -> do
+            let newName = path </> name
+            isDir <- doesDirectoryExist newName
+            if isDir
+              then countEntriesTrad newName
+              else return []
+  return $ (path, length contents) : concat rest
+{-- /snippet countEntriesTrad --}
-- 
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