From 98329e0a3dd4f78b5d815ac3896272ec70904901 Mon Sep 17 00:00:00 2001 From: Eugen Wissner Date: Thu, 11 Dec 2025 10:28:11 +0100 Subject: Add remaining haskell book exercises --- Haskell-book/15/semigroup/src/Or.hs | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) create mode 100644 Haskell-book/15/semigroup/src/Or.hs (limited to 'Haskell-book/15/semigroup/src/Or.hs') diff --git a/Haskell-book/15/semigroup/src/Or.hs b/Haskell-book/15/semigroup/src/Or.hs new file mode 100644 index 0000000..17d4801 --- /dev/null +++ b/Haskell-book/15/semigroup/src/Or.hs @@ -0,0 +1,19 @@ +module Or where + +import Data.Semigroup +import Test.QuickCheck + +data Or a b = + Fst a + | Snd b + deriving (Eq, Show) + +instance Semigroup (Or a b) where + (Snd x) <> _ = Snd x + _ <> x = x + +instance (Arbitrary a, Arbitrary b) => Arbitrary (Or a b) where + arbitrary = do + x <- arbitrary + y <- arbitrary + frequency [ (1, return $ Fst x), (1, return $ Snd y) ] -- cgit v1.2.3