Add remaining haskell book exercises

1 files changed, 53 insertions, 0 deletions

diff --git a/Haskell-book/15/semigroup/src/Two.hs b/Haskell-book/15/semigroup/src/Two.hs
new file mode 100644
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+++ b/Haskell-book/15/semigroup/src/Two.hs
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+module Two where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+data Two a b = Two a b deriving (Eq, Show)
+
+data Three a b c = Three a b c deriving (Eq, Show)
+
+data Four a b c d = Four a b c d deriving (Eq, Show)
+
+instance (Semigroup a, Semigroup b) => Semigroup (Two a b) where
+    (Two x1 y1) <> (Two x2 y2) = Two (x1 <> x2) (y1 <> y2)
+
+instance (Monoid a, Monoid b) => Monoid (Two a b) where
+    mempty = Two mempty mempty
+    mappend (Two x1 y1) (Two x2 y2) = Two (mappend x1 x2) (mappend y1 y2)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Two a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Two x y
+
+instance (Semigroup a, Semigroup b, Semigroup c) => Semigroup (Three a b c) where
+    (Three x1 y1 z1) <> (Three x2 y2 z2) = Three (x1 <> x2) (y1 <> y2) (z1 <> z2)
+
+instance (Monoid a, Monoid b, Monoid c) => Monoid (Three a b c) where
+    mempty = Three mempty mempty mempty
+    mappend (Three x1 y1 z1) (Three x2 y2 z2) = Three (mappend x1 x2) (mappend y1 y2) (mappend z1 z2)
+
+instance (Arbitrary a, Arbitrary b, Arbitrary c) => Arbitrary (Three a b c) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        return $ Three x y z
+
+instance (Semigroup a, Semigroup b, Semigroup c, Semigroup d) => Semigroup (Four a b c d) where
+    (Four x1 y1 z1 t1) <> (Four x2 y2 z2 t2) = Four (x1 <> x2) (y1 <> y2) (z1 <> z2) (t1 <> t2)
+
+instance (Monoid a, Monoid b, Monoid c, Monoid d) => Monoid (Four a b c d) where
+    mempty = Four mempty mempty mempty mempty
+    mappend (Four x1 y1 z1 t1) (Four x2 y2 z2 t2) =
+        Four (mappend x1 x2) (mappend y1 y2) (mappend z1 z2) (mappend t1 t2)
+
+instance (Arbitrary a, Arbitrary b, Arbitrary c, Arbitrary d) => Arbitrary (Four a b c d) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        t <- arbitrary
+        return $ Four x y z t