From 98329e0a3dd4f78b5d815ac3896272ec70904901 Mon Sep 17 00:00:00 2001
From: Eugen Wissner <belka@caraus.de>
Date: Thu, 11 Dec 2025 10:28:11 +0100
Subject: Add remaining haskell book exercises

---
 Haskell-book/12/Maybe.hs | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Haskell-book/12/Maybe.hs

(limited to 'Haskell-book/12/Maybe.hs')

diff --git a/Haskell-book/12/Maybe.hs b/Haskell-book/12/Maybe.hs
new file mode 100644
index 0000000..e83176e
--- /dev/null
+++ b/Haskell-book/12/Maybe.hs
@@ -0,0 +1,19 @@
+module Maybe where
+
+--
+-- 1
+--
+isJust :: Maybe a -> Bool
+isJust (Just _) = True
+isJust Nothing = False
+
+isNothing :: Maybe a -> Bool
+isNothing (Just _) = False
+isNothing Nothing = True
+
+--
+-- 2
+--
+mayybee :: b -> (a -> b) -> Maybe a -> b
+mayybee v f Nothing   = b
+mayybee v f (Maybe x) = f x
-- 
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