Add remaining haskell book exercises

26 files changed, 693 insertions, 0 deletions

diff --git a/Haskell-book/15/Madness.hs b/Haskell-book/15/Madness.hs
new file mode 100644
index 0000000..9d6aa34
--- /dev/null
+++ b/Haskell-book/15/Madness.hs
@@ -0,0 +1,36 @@
+module Madness where
+
+import Data.Monoid
+
+type Verb = String
+type Adjective = String
+type Adverb = String
+type Noun = String
+type Exclamation = String
+
+madlibbin' :: Exclamation
+           -> Adverb
+           -> Noun
+           -> Adjective
+           -> String
+madlibbin' e adv noun adj =
+    e <> "! he said " <>
+    adv <> " as he jumped into his car " <>
+    noun <> " and drove off with his " <>
+    adj <> " wife."
+
+madlibbinBetter' :: Exclamation
+                 -> Adverb
+                 -> Noun
+                 -> Adjective
+                 -> String
+madlibbinBetter' e adv noun adj =
+    mconcat [ e
+            , "! he said "
+            ,  adv
+            , " as he jumped into his car "
+            , noun
+            , " and drove off with his "
+            , adj
+            , " wife."
+            ]
diff --git a/Haskell-book/15/optional.cabal b/Haskell-book/15/optional.cabal
new file mode 100644
index 0000000..1251d94
--- /dev/null
+++ b/Haskell-book/15/optional.cabal
@@ -0,0 +1,45 @@
+name:           optional
+version:        0.1.0.0
+author:         Eugen Wissner
+maintainer:     belka@caraus.de
+copyright:      2018 Eugen Wissner
+license:        BSD3
+build-type:     Simple
+cabal-version:  >= 1.10
+
+library
+  hs-source-dirs:
+      src
+  build-depends:
+      base >=4.7 && <5
+  exposed-modules:
+      Optional
+  other-modules:
+      Paths_optional
+  default-language: Haskell2010
+
+test-suite optional-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  hs-source-dirs:
+      test
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , hspec
+    , optional
+  other-modules:
+      Paths_optional
+  default-language: Haskell2010
+
+test-suite first-test
+  type: exitcode-stdio-1.0
+  main-is: First.hs
+  hs-source-dirs:
+      app
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      base >=4.7 && <5
+    , QuickCheck
+    , optional
+  default-language: Haskell2010
diff --git a/Haskell-book/15/optional/.gitignore b/Haskell-book/15/optional/.gitignore
new file mode 100644
index 0000000..e0007e6
--- /dev/null
+++ b/Haskell-book/15/optional/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+optional.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/15/optional/Setup.hs b/Haskell-book/15/optional/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/15/optional/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/15/optional/app/First.hs b/Haskell-book/15/optional/app/First.hs
new file mode 100644
index 0000000..929cd6b
--- /dev/null
+++ b/Haskell-book/15/optional/app/First.hs
@@ -0,0 +1,48 @@
+module Main where
+
+import Data.Monoid
+import Optional
+import Test.QuickCheck
+
+newtype First' a =
+    First' { getFirst' :: Optional a }
+    deriving (Eq, Show)
+
+instance Monoid (First' a) where
+    mempty = First' Nada
+    mappend (First' Nada) x = x
+    mappend x _ = x
+
+instance Arbitrary a => Arbitrary (First' a) where
+    arbitrary = frequency [ (1, return $ First' Nada)
+                          , (1, fmap (First' . Only) arbitrary) ]
+
+firstMappend :: First' a
+             -> First' a
+             -> First' a
+firstMappend = mappend
+
+type FirstMappend =
+    First' String
+  -> First' String
+  -> First' String
+  -> Bool
+
+type FstId =
+    First' String -> Bool
+
+monoidAssoc :: (Eq m, Monoid m) => m -> m -> m -> Bool
+monoidAssoc a b c =
+    (a <> (b <> c)) == ((a <> b) <> c)
+
+monoidLeftIdentity :: (Eq m, Monoid m) => m -> Bool
+monoidLeftIdentity a = (mempty <> a) == a
+
+monoidRightIdentity :: (Eq m, Monoid m) => m -> Bool
+monoidRightIdentity a = (a <> mempty) == a
+
+main :: IO ()
+main = do
+    quickCheck (monoidAssoc :: FirstMappend)
+    quickCheck (monoidLeftIdentity :: FstId)
+    quickCheck (monoidRightIdentity :: FstId)
diff --git a/Haskell-book/15/optional/package.yaml b/Haskell-book/15/optional/package.yaml
new file mode 100644
index 0000000..87ac223
--- /dev/null
+++ b/Haskell-book/15/optional/package.yaml
@@ -0,0 +1,35 @@
+name:                optional
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+
+library:
+  source-dirs: src
+
+tests:
+  optional-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - optional
+    - hspec
+
+  first-test:
+      main: First.hs
+      source-dirs: app
+      ghc-options:
+      - -threaded
+      - -rtsopts
+      - -with-rtsopts=-N
+      dependencies:
+      - optional
+      - QuickCheck
diff --git a/Haskell-book/15/optional/src/Optional.hs b/Haskell-book/15/optional/src/Optional.hs
new file mode 100644
index 0000000..d85d8a5
--- /dev/null
+++ b/Haskell-book/15/optional/src/Optional.hs
@@ -0,0 +1,12 @@
+module Optional where
+
+data Optional a =
+    Nada
+  | Only a
+  deriving (Eq, Show)
+
+instance Monoid a => Monoid (Optional a) where
+    mempty = Nada
+    mappend x Nada = x
+    mappend Nada x = x
+    mappend (Only x) (Only y) = Only (mappend x y)
diff --git a/Haskell-book/15/optional/stack.yaml b/Haskell-book/15/optional/stack.yaml
new file mode 100644
index 0000000..1de6a19
--- /dev/null
+++ b/Haskell-book/15/optional/stack.yaml
@@ -0,0 +1,66 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-10.2
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+#
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.6"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor
\ No newline at end of file
diff --git a/Haskell-book/15/optional/test/Spec.hs b/Haskell-book/15/optional/test/Spec.hs
new file mode 100644
index 0000000..189d143
--- /dev/null
+++ b/Haskell-book/15/optional/test/Spec.hs
@@ -0,0 +1,21 @@
+import Data.Monoid
+import Optional
+import Test.Hspec
+
+main :: IO ()
+main = hspec $ do
+    describe "Sum" $ do
+        it "1 + 1 is 2" $ do
+            Only (Sum 1) `mappend` Only (Sum 1) `shouldBe` Only (Sum {getSum = 2})
+    describe "Product" $ do
+        it "4 * 2 is 8" $ do
+            Only (Product 4) `mappend` Only (Product 2) `shouldBe` Only (Product {getProduct = 8})
+    describe "Sum with Nada" $ do
+        it "1 + Nada is 1" $ do
+            Only (Sum 1) `mappend` Nada `shouldBe` Only (Sum {getSum = 1})
+    describe "List" $ do
+        it "[1] <> Nada is [1]" $ do
+            Only [1] `mappend` Nada `shouldBe` Only [1]
+    describe "Nada with sum" $ do
+        it "Nada + 1 is 1" $ do
+            Nada `mappend` Only (Sum 1) `shouldBe` Only (Sum {getSum = 1})
diff --git a/Haskell-book/15/orphan-instance/Listy.hs b/Haskell-book/15/orphan-instance/Listy.hs
new file mode 100644
index 0000000..c99720a
--- /dev/null
+++ b/Haskell-book/15/orphan-instance/Listy.hs
@@ -0,0 +1,10 @@
+module Listy where
+
+newtype Listy a =
+    Listy [a]
+    deriving (Eq, Show)
+
+instance Monoid (Listy a) where
+    mempty = Listy []
+    mappend (Listy l) (Listy l') =
+        Listy $ mappend l l'
diff --git a/Haskell-book/15/orphan-instance/ListyInstances.hs b/Haskell-book/15/orphan-instance/ListyInstances.hs
new file mode 100644
index 0000000..39f7210
--- /dev/null
+++ b/Haskell-book/15/orphan-instance/ListyInstances.hs
@@ -0,0 +1,9 @@
+module ListyInstances where
+
+import Data.Monoid
+import Listy
+
+instance Monoid (Listy a) where
+    mempty = Listy []
+    mappend (Listy l) (Listy l') =
+        Listy $ mappend l l'
diff --git a/Haskell-book/15/semigroup/.gitignore b/Haskell-book/15/semigroup/.gitignore
new file mode 100644
index 0000000..b9db70a
--- /dev/null
+++ b/Haskell-book/15/semigroup/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+semigroup.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/15/semigroup/Setup.hs b/Haskell-book/15/semigroup/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/15/semigroup/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/15/semigroup/app/Main.hs b/Haskell-book/15/semigroup/app/Main.hs
new file mode 100644
index 0000000..237aefe
--- /dev/null
+++ b/Haskell-book/15/semigroup/app/Main.hs
@@ -0,0 +1,18 @@
+module Main where
+
+import Data.Monoid
+import Mem
+
+f' :: Num a => Mem a String
+f' = Mem $ \s -> ("hi", s + 1)
+
+main :: IO ()
+main = do
+    let rmzero = runMem mempty 0
+        rmleft = runMem (f' <> mempty) 0
+        rmright = runMem (mempty <> f') 0
+    print $ (rmleft :: (String, Int))
+    print $ (rmright :: (String, Int))
+    print $ (rmzero :: (String, Int))
+    print $ rmleft == runMem f' 0
+    print $ rmright == runMem f' 0
diff --git a/Haskell-book/15/semigroup/package.yaml b/Haskell-book/15/semigroup/package.yaml
new file mode 100644
index 0000000..8e3b72c
--- /dev/null
+++ b/Haskell-book/15/semigroup/package.yaml
@@ -0,0 +1,36 @@
+name:                semigroup
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+
+library:
+  source-dirs: src
+  dependencies:
+  - QuickCheck
+
+executables:
+ semigroup-exe:
+   main:                Main.hs
+   source-dirs:         app
+   ghc-options:
+   - -threaded
+   - -rtsopts
+   - -with-rtsopts=-N
+   dependencies:
+   - semigroup
+
+tests:
+  semigroup-test:
+    main:                Main.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - QuickCheck
+    - semigroup
diff --git a/Haskell-book/15/semigroup/src/Bool.hs b/Haskell-book/15/semigroup/src/Bool.hs
new file mode 100644
index 0000000..2efdd34
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Bool.hs
@@ -0,0 +1,30 @@
+module Bool where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+newtype BoolConj = BoolConj Bool deriving (Eq, Show)
+
+instance Semigroup BoolConj where
+    (BoolConj True) <> (BoolConj True) = BoolConj True
+    _ <> _ = BoolConj False
+
+instance Monoid BoolConj where
+    mempty = BoolConj True
+    mappend = (<>)
+
+instance Arbitrary BoolConj where
+    arbitrary = fmap BoolConj arbitrary
+
+newtype BoolDisj = BoolDisj Bool deriving (Eq, Show)
+
+instance Semigroup BoolDisj where
+    (BoolDisj False) <> (BoolDisj False) = BoolDisj False
+    _ <> _ = BoolDisj True
+
+instance Monoid BoolDisj where
+    mempty = BoolDisj False
+    mappend = (<>)
+
+instance Arbitrary BoolDisj where
+    arbitrary = fmap BoolDisj arbitrary
diff --git a/Haskell-book/15/semigroup/src/Combine.hs b/Haskell-book/15/semigroup/src/Combine.hs
new file mode 100644
index 0000000..fe420dd
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Combine.hs
@@ -0,0 +1,25 @@
+{-# LANGUAGE FlexibleInstances #-}
+module Combine where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+newtype Combine a b =
+    Combine { unCombine :: (a -> b) }
+
+instance Semigroup b => Semigroup (Combine a b) where
+    (Combine f1) <> (Combine f2) = Combine f
+        where f x = (f1 x) <> (f2 x)
+
+instance (Monoid b) => Monoid (Combine a b) where
+    mempty = Combine $ \_ -> mempty
+    mappend (Combine f1) (Combine f2) = Combine f
+        where f x = mappend (f1 x) (f2 x)
+
+instance (Num a, CoArbitrary a, Arbitrary b) => Arbitrary (Combine a b) where
+    arbitrary = do
+        f <- arbitrary
+        return $ Combine (\n -> f n)
+
+instance (Show a, Show b) => Show (Combine a b) where
+    show _ = "a -> b"
diff --git a/Haskell-book/15/semigroup/src/Comp.hs b/Haskell-book/15/semigroup/src/Comp.hs
new file mode 100644
index 0000000..f7224da
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Comp.hs
@@ -0,0 +1,22 @@
+module Comp where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+newtype Comp a =
+    Comp { unComp :: (a -> a) }
+
+instance Semigroup a => Semigroup (Comp a) where
+    (Comp f1) <> (Comp f2) = Comp f
+        where f x = (f1 x) <> (f2 x)
+
+instance Monoid a => Monoid (Comp a) where
+    mempty = Comp $ \_ -> mempty
+    mappend (Comp f1) (Comp f2) = Comp f
+        where f x = mappend (f1 x) (f2 x)
+
+instance (Arbitrary a, CoArbitrary a) => Arbitrary (Comp a) where
+    arbitrary = fmap Comp arbitrary
+
+instance Show (Comp a) where
+    show _ = "a -> a"
diff --git a/Haskell-book/15/semigroup/src/Identity.hs b/Haskell-book/15/semigroup/src/Identity.hs
new file mode 100644
index 0000000..cb7180a
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Identity.hs
@@ -0,0 +1,16 @@
+module Identity where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+newtype Identity a = Identity a deriving (Show, Eq)
+
+instance Semigroup a => Semigroup (Identity a) where
+    (Identity x) <> (Identity y) = Identity (x <> y)
+
+instance Monoid a => Monoid (Identity a) where
+    mempty = Identity mempty
+    mappend (Identity x) (Identity y) = Identity $ mappend x y
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = fmap Identity arbitrary
diff --git a/Haskell-book/15/semigroup/src/Mem.hs b/Haskell-book/15/semigroup/src/Mem.hs
new file mode 100644
index 0000000..575e82d
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Mem.hs
@@ -0,0 +1,11 @@
+module Mem where
+
+newtype Mem s a =
+    Mem {
+        runMem :: s -> (a,s)
+    }
+
+instance Monoid a => Monoid (Mem s a) where
+    mempty = Mem $ \x -> (mempty, x)
+    mappend (Mem f1) (Mem f2) = Mem f
+        where f x = ((mappend (fst $ f1 x) (fst $ f2 x)), snd $ f2 $ snd $ f1 x)
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) ]
diff --git a/Haskell-book/15/semigroup/src/Trivial.hs b/Haskell-book/15/semigroup/src/Trivial.hs
new file mode 100644
index 0000000..de9a1ad
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Trivial.hs
@@ -0,0 +1,16 @@
+module Trivial where
+
+import Data.Semigroup
+import Test.QuickCheck
+
+data Trivial = Trivial deriving (Eq, Show)
+
+instance Semigroup Trivial where
+    _ <> _ = Trivial
+
+instance Arbitrary Trivial where
+    arbitrary = return Trivial
+
+instance Monoid Trivial where
+    mempty = undefined
+    mappend = (<>)
diff --git a/Haskell-book/15/semigroup/src/Two.hs b/Haskell-book/15/semigroup/src/Two.hs
new file mode 100644
index 0000000..70c2760
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Two.hs
@@ -0,0 +1,53 @@
+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
diff --git a/Haskell-book/15/semigroup/src/Validation.hs b/Haskell-book/15/semigroup/src/Validation.hs
new file mode 100644
index 0000000..a5d1c9c
--- /dev/null
+++ b/Haskell-book/15/semigroup/src/Validation.hs
@@ -0,0 +1,17 @@
+module Validation where
+
+import Data.Semigroup
+import Test.QuickCheck (arbitrary, Arbitrary(..), frequency)
+
+data Validation a b = Failure a | Success b deriving (Eq, Show)
+
+instance Semigroup a => Semigroup (Validation a b) where
+    (Success x) <> _ = Success x
+    _ <> (Success x) = Success x
+    (Failure x) <> (Failure y) = Failure $ x <> y
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Validation a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        frequency [ (1, return $ Success x), (1, return $ Failure y) ]
diff --git a/Haskell-book/15/semigroup/stack.yaml b/Haskell-book/15/semigroup/stack.yaml
new file mode 100644
index 0000000..1de6a19
--- /dev/null
+++ b/Haskell-book/15/semigroup/stack.yaml
@@ -0,0 +1,66 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-10.2
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+#
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=1.6"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor
\ No newline at end of file
diff --git a/Haskell-book/15/semigroup/test/Main.hs b/Haskell-book/15/semigroup/test/Main.hs
new file mode 100644
index 0000000..146ffdc
--- /dev/null
+++ b/Haskell-book/15/semigroup/test/Main.hs
@@ -0,0 +1,72 @@
+import Trivial
+import Identity
+import Two
+import Test.QuickCheck
+import Bool
+import Or
+import Combine
+import Data.Semigroup
+import Comp
+import Validation
+
+semigroupAssoc :: (Eq m, Semigroup m) => m -> m -> m -> Bool
+semigroupAssoc a b c = (a <> (b <> c)) == ((a <> b) <> c)
+
+type TrivAssoc =
+    Trivial -> Trivial -> Trivial -> Bool
+
+type TwoType = Two Trivial Trivial
+type ThreeType = Three Trivial Trivial Trivial
+type FourType = Four Trivial Trivial Trivial Trivial
+
+type CombineType = Combine Int (Sum Int)
+semigroupCombineAssoc :: CombineType -> CombineType -> CombineType -> Bool
+semigroupCombineAssoc a b c =
+    ((unCombine (a <> (b <> c))) 8) == ((unCombine ((a <> b) <> c)) 8)
+
+semigroupCompAssoc :: Comp (Sum Int) -> Comp (Sum Int) -> Comp (Sum Int) -> Bool
+semigroupCompAssoc a b c =
+    ((unComp (a <> (b <> c))) (Sum 8)) == ((unComp ((a <> b) <> c)) (Sum 8))
+
+monoidLeftIdentity :: (Eq m, Monoid m)
+                   => m
+                   -> Bool
+monoidLeftIdentity a = (mappend mempty a) == a
+
+monoidRightIdentity :: (Eq m, Monoid m)
+                    => m
+                    -> Bool
+monoidRightIdentity a = (mappend a mempty) == a
+
+
+
+main :: IO ()
+main = do
+    quickCheck (semigroupAssoc :: TrivAssoc)
+    quickCheck (monoidLeftIdentity :: Trivial -> Bool)
+    quickCheck (monoidRightIdentity :: Trivial -> Bool)
+
+    quickCheck (semigroupAssoc :: Identity Trivial -> Identity Trivial -> Identity Trivial -> Bool)
+    quickCheck (monoidLeftIdentity :: Identity (Sum Int)-> Bool)
+    quickCheck (monoidRightIdentity :: Identity (Sum Int) -> Bool)
+
+    quickCheck (semigroupAssoc :: TwoType -> TwoType -> TwoType -> Bool)
+    quickCheck (monoidLeftIdentity :: TwoType -> Bool)
+    quickCheck (monoidRightIdentity :: TwoType -> Bool)
+    quickCheck (semigroupAssoc :: ThreeType -> ThreeType -> ThreeType -> Bool)
+    quickCheck (monoidLeftIdentity :: ThreeType -> Bool)
+    quickCheck (monoidRightIdentity :: ThreeType -> Bool)
+    quickCheck (semigroupAssoc :: FourType -> FourType -> FourType -> Bool)
+    quickCheck (monoidLeftIdentity :: FourType -> Bool)
+    quickCheck (monoidRightIdentity :: FourType -> Bool)
+
+    quickCheck (semigroupAssoc :: BoolConj -> BoolConj -> BoolConj -> Bool)
+    quickCheck (monoidLeftIdentity :: BoolConj -> Bool)
+    quickCheck (monoidRightIdentity :: BoolConj -> Bool)
+    quickCheck (semigroupAssoc :: BoolDisj -> BoolDisj -> BoolDisj -> Bool)
+    quickCheck (monoidLeftIdentity :: BoolDisj -> Bool)
+    quickCheck (monoidRightIdentity :: BoolDisj -> Bool)
+    quickCheck (semigroupAssoc :: Or Trivial Trivial -> Or Trivial Trivial -> Or Trivial Trivial -> Bool)
+    quickCheck semigroupCombineAssoc
+    quickCheck semigroupCompAssoc
+    quickCheck (semigroupAssoc :: Validation String Int -> Validation String Int -> Validation String Int -> Bool)