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: [PATCH] Add remaining haskell book exercises

---
 Haskell-book/12/Exercises.hs                  | 202 ++++++++
 Haskell-book/12/Maybe.hs                      |  19 +
 Haskell-book/13/Cipher.hs                     |  16 +
 Haskell-book/13/Palindrome.hs                 |  20 +
 Haskell-book/13/Person.hs                     |  34 ++
 Haskell-book/14/addition/Addition.hs          |  35 ++
 Haskell-book/14/addition/LICENSE              |  30 ++
 Haskell-book/14/addition/README.md            |   1 +
 Haskell-book/14/addition/Setup.hs             |   2 +
 Haskell-book/14/addition/addition.cabal       |  17 +
 Haskell-book/14/addition/stack.yaml           |  66 +++
 Haskell-book/14/addition/stack.yaml.lock      |  12 +
 Haskell-book/14/morse/.gitignore              |   3 +
 Haskell-book/14/morse/ChangeLog.md            |   3 +
 Haskell-book/14/morse/LICENSE                 |  30 ++
 Haskell-book/14/morse/README.md               |   1 +
 Haskell-book/14/morse/Setup.hs                |   2 +
 Haskell-book/14/morse/src/Main.hs             |  59 +++
 Haskell-book/14/morse/src/Morse.hs            |  68 +++
 Haskell-book/14/morse/src/WordNumber.hs       |  26 +
 Haskell-book/14/morse/stack.yaml              |  66 +++
 Haskell-book/14/morse/stack.yaml.lock         |  12 +
 Haskell-book/14/morse/tests/CoArbitrary.hs    |  16 +
 Haskell-book/14/morse/tests/WordNumberTest.hs |  24 +
 Haskell-book/14/morse/tests/tests.hs          |  86 ++++
 Haskell-book/14/qc/qc.cabal                   |  32 ++
 Haskell-book/14/qc/src/UsingQuickCheck.hs     |  58 +++
 Haskell-book/14/qc/stack.yaml                 |  66 +++
 Haskell-book/14/qc/tests/Idempotence.hs       |  30 ++
 .../14/qc/tests/UsingQuickCheckTest.hs        | 128 +++++
 Haskell-book/15/Madness.hs                    |  36 ++
 Haskell-book/15/optional.cabal                |  45 ++
 Haskell-book/15/optional/.gitignore           |   3 +
 Haskell-book/15/optional/Setup.hs             |   2 +
 Haskell-book/15/optional/app/First.hs         |  48 ++
 Haskell-book/15/optional/package.yaml         |  35 ++
 Haskell-book/15/optional/src/Optional.hs      |  12 +
 Haskell-book/15/optional/stack.yaml           |  66 +++
 Haskell-book/15/optional/test/Spec.hs         |  21 +
 Haskell-book/15/orphan-instance/Listy.hs      |  10 +
 .../15/orphan-instance/ListyInstances.hs      |   9 +
 Haskell-book/15/semigroup/.gitignore          |   3 +
 Haskell-book/15/semigroup/Setup.hs            |   2 +
 Haskell-book/15/semigroup/app/Main.hs         |  18 +
 Haskell-book/15/semigroup/package.yaml        |  36 ++
 Haskell-book/15/semigroup/src/Bool.hs         |  30 ++
 Haskell-book/15/semigroup/src/Combine.hs      |  25 +
 Haskell-book/15/semigroup/src/Comp.hs         |  22 +
 Haskell-book/15/semigroup/src/Identity.hs     |  16 +
 Haskell-book/15/semigroup/src/Mem.hs          |  11 +
 Haskell-book/15/semigroup/src/Or.hs           |  19 +
 Haskell-book/15/semigroup/src/Trivial.hs      |  16 +
 Haskell-book/15/semigroup/src/Two.hs          |  53 ++
 Haskell-book/15/semigroup/src/Validation.hs   |  17 +
 Haskell-book/15/semigroup/stack.yaml          |  66 +++
 Haskell-book/15/semigroup/test/Main.hs        |  72 +++
 Haskell-book/16/Exercises.hs                  | 154 ++++++
 Haskell-book/16/HeavyLifting.hs               |  16 +
 Haskell-book/16/Possibly.hs                   |  10 +
 Haskell-book/16/Short.hs                      |  10 +
 Haskell-book/16/func/.gitignore               |   3 +
 Haskell-book/16/func/Setup.hs                 |   2 +
 Haskell-book/16/func/app/Main.hs              |   6 +
 Haskell-book/16/func/package.yaml             |  34 ++
 Haskell-book/16/func/src/Func.hs              |  89 ++++
 Haskell-book/16/func/stack.yaml               |  66 +++
 Haskell-book/16/func/test/Spec.hs             |  54 ++
 Haskell-book/17/Combinations.hs               |  12 +
 Haskell-book/17/Constant.hs                   |  13 +
 Haskell-book/17/Exercises/.gitignore          |   3 +
 Haskell-book/17/Exercises/Setup.hs            |   2 +
 Haskell-book/17/Exercises/app/Main.hs         |   6 +
 Haskell-book/17/Exercises/package.yaml        |  35 ++
 Haskell-book/17/Exercises/src/Exercises.hs    | 124 +++++
 Haskell-book/17/Exercises/stack.yaml          |  66 +++
 Haskell-book/17/Exercises/test/Spec.hs        |  26 +
 Haskell-book/17/FixerUpper.hs                 |   6 +
 Haskell-book/17/Identity.hs                   |   9 +
 Haskell-book/17/ListApplicative/.gitignore    |   3 +
 Haskell-book/17/ListApplicative/Setup.hs      |   2 +
 Haskell-book/17/ListApplicative/app/Main.hs   |   6 +
 Haskell-book/17/ListApplicative/package.yaml  |  35 ++
 Haskell-book/17/ListApplicative/src/List.hs   |  46 ++
 .../17/ListApplicative/src/Validation.hs      |  27 +
 .../17/ListApplicative/src/ZipList.hs         |  40 ++
 Haskell-book/17/ListApplicative/stack.yaml    |  66 +++
 Haskell-book/17/ListApplicative/test/Spec.hs  |  16 +
 Haskell-book/18/Bind.hs                       |   6 +
 Haskell-book/18/Functions.hs                  |  21 +
 Haskell-book/18/Instance/.gitignore           |   3 +
 Haskell-book/18/Instance/Setup.hs             |   2 +
 Haskell-book/18/Instance/package.yaml         |  26 +
 Haskell-book/18/Instance/src/Identity.hs      |  24 +
 Haskell-book/18/Instance/src/List.hs          |  44 ++
 Haskell-book/18/Instance/src/Nope.hs          |  23 +
 .../18/Instance/src/PhhhbbtttEither.hs        |  38 ++
 Haskell-book/18/Instance/src/Sum.hs           |  31 ++
 Haskell-book/18/Instance/stack.yaml           |  66 +++
 Haskell-book/18/Instance/test/Spec.hs         |  29 ++
 Haskell-book/19/shawty/.gitignore             |   3 +
 Haskell-book/19/shawty/ChangeLog.md           |   3 +
 Haskell-book/19/shawty/LICENSE                |  30 ++
 Haskell-book/19/shawty/README.md              |   1 +
 Haskell-book/19/shawty/Setup.hs               |   2 +
 Haskell-book/19/shawty/app/Main.hs            | 107 ++++
 Haskell-book/19/shawty/package.yaml           |  31 ++
 Haskell-book/19/shawty/stack.yaml             |  66 +++
 Haskell-book/19/shawty/test/Spec.hs           |   2 +
 Haskell-book/20/Exercises.hs                  |  38 ++
 Haskell-book/20/LibraryFunctions.hs           |  51 ++
 Haskell-book/21/instances/.gitignore          |   3 +
 Haskell-book/21/instances/LICENSE             |  30 ++
 Haskell-book/21/instances/Setup.hs            |   2 +
 Haskell-book/21/instances/package.yaml        |  24 +
 Haskell-book/21/instances/src/Lib.hs          | 222 ++++++++
 Haskell-book/21/instances/src/SkiFree.hs      |  32 ++
 Haskell-book/21/instances/src/Tree.hs         |  44 ++
 Haskell-book/21/instances/stack.yaml          |  66 +++
 Haskell-book/21/instances/test/Spec.hs        |  35 ++
 Haskell-book/22/Ash.hs                        |   7 +
 Haskell-book/22/Reader.hs                     |  62 +++
 Haskell-book/22/ReaderPractice.hs             |  94 ++++
 Haskell-book/22/WarmingUp.hs                  |  21 +
 Haskell-book/23/FizzBuzz.hs                   |  29 ++
 Haskell-book/23/Moi.hs                        |  34 ++
 Haskell-book/23/RandomExample/.gitignore      |   3 +
 Haskell-book/23/RandomExample/LICENSE         |  30 ++
 Haskell-book/23/RandomExample/Setup.hs        |   2 +
 Haskell-book/23/RandomExample/app/Main.hs     |   4 +
 Haskell-book/23/RandomExample/package.yaml    |  34 ++
 .../23/RandomExample/src/RandomExample.hs     |  31 ++
 .../23/RandomExample/src/RandomExample2.hs    |  54 ++
 Haskell-book/23/RandomExample/stack.yaml      |  66 +++
 Haskell-book/23/RandomExample/test/Spec.hs    |   2 +
 Haskell-book/24/LearnParsers/.gitignore       |   3 +
 Haskell-book/24/LearnParsers/ChangeLog.md     |   3 +
 Haskell-book/24/LearnParsers/Setup.hs         |   2 +
 Haskell-book/24/LearnParsers/app/Main.hs      |  24 +
 Haskell-book/24/LearnParsers/package.yaml     |  24 +
 .../24/LearnParsers/src/LearnParsers.hs       |  45 ++
 .../24/LearnParsers/src/Text/Fractions.hs     |  31 ++
 Haskell-book/24/LearnParsers/stack.yaml       |  66 +++
 Haskell-book/24/ParserExercises/.gitignore    |   3 +
 Haskell-book/24/ParserExercises/Setup.hs      |   2 +
 Haskell-book/24/ParserExercises/package.yaml  |  38 ++
 .../24/ParserExercises/src/Base10Integer.hs   |  52 ++
 .../24/ParserExercises/src/IPAddress.hs       | 260 ++++++++++
 .../24/ParserExercises/src/LogParser.hs       |  83 +++
 .../24/ParserExercises/src/PhoneNumber.hs     |  28 +
 Haskell-book/24/ParserExercises/src/SemVer.hs |  51 ++
 Haskell-book/24/ParserExercises/stack.yaml    |  66 +++
 .../24/ParserExercises/test/LogTest/Main.hs   |  14 +
 .../24/ParserExercises/test/Spec/Main.hs      | 107 ++++
 Haskell-book/24/language-dot/LICENSE          |  29 ++
 Haskell-book/24/language-dot/Setup.hs         |  12 +
 .../24/language-dot/language-dot.cabal        |  59 +++
 .../24/language-dot/src/Language/Dot.hs       |  10 +
 .../language-dot/src/Language/Dot/Parser.hs   | 486 ++++++++++++++++++
 .../language-dot/src/Language/Dot/Pretty.hs   | 135 +++++
 .../language-dot/src/Language/Dot/Syntax.hs   |  92 ++++
 Haskell-book/24/language-dot/src/ppdot.hs     |  72 +++
 Haskell-book/24/language-dot/src/test.hs      | 120 +++++
 Haskell-book/25/Bifunctor/.gitignore          |   3 +
 Haskell-book/25/Bifunctor/Setup.hs            |   2 +
 Haskell-book/25/Bifunctor/package.yaml        |  23 +
 Haskell-book/25/Bifunctor/src/Bifunctor.hs    |  68 +++
 Haskell-book/25/Bifunctor/stack.yaml          |  66 +++
 Haskell-book/25/Bifunctor/test/Spec.hs        |   2 +
 Haskell-book/25/Twinplicative/.gitignore      |   3 +
 Haskell-book/25/Twinplicative/LICENSE         |  30 ++
 Haskell-book/25/Twinplicative/Setup.hs        |   2 +
 Haskell-book/25/Twinplicative/package.yaml    |  13 +
 .../25/Twinplicative/src/Twinplicative.hs     |  42 ++
 Haskell-book/25/Twinplicative/stack.yaml      |  66 +++
 Haskell-book/26/Embedded/Embedded.cabal       |  40 ++
 Haskell-book/26/Embedded/Setup.hs             |   2 +
 Haskell-book/26/Embedded/package.yaml         |  24 +
 Haskell-book/26/Embedded/src/OuterInner.hs    |  30 ++
 Haskell-book/26/Embedded/stack.yaml           |  66 +++
 Haskell-book/26/Embedded/test/Spec.hs         |   2 +
 Haskell-book/26/Exercises/.gitignore          |   3 +
 Haskell-book/26/Exercises/Setup.hs            |   2 +
 Haskell-book/26/Exercises/app/Main.hs         |  61 +++
 Haskell-book/26/Exercises/package.yaml        |  37 ++
 Haskell-book/26/Exercises/src/Exercises.hs    |  75 +++
 Haskell-book/26/Exercises/src/Fix.hs          |  24 +
 Haskell-book/26/Exercises/stack.yaml          |  65 +++
 Haskell-book/26/Exercises/test/Spec.hs        |  19 +
 Haskell-book/26/MaybeT/.gitignore             |   3 +
 Haskell-book/26/MaybeT/Setup.hs               |   2 +
 Haskell-book/26/MaybeT/package.yaml           |  23 +
 Haskell-book/26/MaybeT/src/Either.hs          |  56 ++
 Haskell-book/26/MaybeT/src/Identity.hs        |  43 ++
 Haskell-book/26/MaybeT/src/Maybe.hs           |  40 ++
 Haskell-book/26/MaybeT/src/MonadIO.hs         |   5 +
 Haskell-book/26/MaybeT/src/MonadTrans.hs      |   7 +
 Haskell-book/26/MaybeT/src/Reader.hs          |  35 ++
 Haskell-book/26/MaybeT/src/State.hs           |  41 ++
 Haskell-book/26/MaybeT/stack.yaml             |  66 +++
 Haskell-book/26/MaybeT/test/Spec.hs           |   2 +
 Haskell-book/26/Morra/.gitignore              |   3 +
 Haskell-book/26/Morra/Setup.hs                |   2 +
 Haskell-book/26/Morra/app/Main.hs             |  69 +++
 Haskell-book/26/Morra/package.yaml            |  21 +
 Haskell-book/26/Morra/stack.yaml              |  65 +++
 Haskell-book/27/BottomExpression.hs           |   7 +
 Haskell-book/27/StrictList.hs                 |  20 +
 Haskell-book/28/Bench/.gitignore              |   3 +
 Haskell-book/28/Bench/Setup.hs                |   2 +
 Haskell-book/28/Bench/app/Main.hs             |  46 ++
 Haskell-book/28/Bench/package.yaml            |  21 +
 Haskell-book/28/Bench/stack.yaml              |  65 +++
 Haskell-book/28/DifferenceList/.gitignore     |   3 +
 Haskell-book/28/DifferenceList/Setup.hs       |   2 +
 Haskell-book/28/DifferenceList/app/Main.hs    |  46 ++
 Haskell-book/28/DifferenceList/package.yaml   |  37 ++
 .../28/DifferenceList/src/Data/DList.hs       |  40 ++
 .../28/DifferenceList/src/Data/Queue.hs       |  44 ++
 Haskell-book/28/DifferenceList/stack.yaml     |  65 +++
 Haskell-book/28/DifferenceList/test/Spec.hs   |  33 ++
 README.md                                     |   9 +-
 221 files changed, 8033 insertions(+), 2 deletions(-)
 create mode 100644 Haskell-book/12/Exercises.hs
 create mode 100644 Haskell-book/12/Maybe.hs
 create mode 100644 Haskell-book/13/Cipher.hs
 create mode 100644 Haskell-book/13/Palindrome.hs
 create mode 100644 Haskell-book/13/Person.hs
 create mode 100644 Haskell-book/14/addition/Addition.hs
 create mode 100644 Haskell-book/14/addition/LICENSE
 create mode 100644 Haskell-book/14/addition/README.md
 create mode 100644 Haskell-book/14/addition/Setup.hs
 create mode 100644 Haskell-book/14/addition/addition.cabal
 create mode 100644 Haskell-book/14/addition/stack.yaml
 create mode 100644 Haskell-book/14/addition/stack.yaml.lock
 create mode 100644 Haskell-book/14/morse/.gitignore
 create mode 100644 Haskell-book/14/morse/ChangeLog.md
 create mode 100644 Haskell-book/14/morse/LICENSE
 create mode 100644 Haskell-book/14/morse/README.md
 create mode 100644 Haskell-book/14/morse/Setup.hs
 create mode 100644 Haskell-book/14/morse/src/Main.hs
 create mode 100644 Haskell-book/14/morse/src/Morse.hs
 create mode 100644 Haskell-book/14/morse/src/WordNumber.hs
 create mode 100644 Haskell-book/14/morse/stack.yaml
 create mode 100644 Haskell-book/14/morse/stack.yaml.lock
 create mode 100644 Haskell-book/14/morse/tests/CoArbitrary.hs
 create mode 100644 Haskell-book/14/morse/tests/WordNumberTest.hs
 create mode 100644 Haskell-book/14/morse/tests/tests.hs
 create mode 100644 Haskell-book/14/qc/qc.cabal
 create mode 100644 Haskell-book/14/qc/src/UsingQuickCheck.hs
 create mode 100644 Haskell-book/14/qc/stack.yaml
 create mode 100644 Haskell-book/14/qc/tests/Idempotence.hs
 create mode 100644 Haskell-book/14/qc/tests/UsingQuickCheckTest.hs
 create mode 100644 Haskell-book/15/Madness.hs
 create mode 100644 Haskell-book/15/optional.cabal
 create mode 100644 Haskell-book/15/optional/.gitignore
 create mode 100644 Haskell-book/15/optional/Setup.hs
 create mode 100644 Haskell-book/15/optional/app/First.hs
 create mode 100644 Haskell-book/15/optional/package.yaml
 create mode 100644 Haskell-book/15/optional/src/Optional.hs
 create mode 100644 Haskell-book/15/optional/stack.yaml
 create mode 100644 Haskell-book/15/optional/test/Spec.hs
 create mode 100644 Haskell-book/15/orphan-instance/Listy.hs
 create mode 100644 Haskell-book/15/orphan-instance/ListyInstances.hs
 create mode 100644 Haskell-book/15/semigroup/.gitignore
 create mode 100644 Haskell-book/15/semigroup/Setup.hs
 create mode 100644 Haskell-book/15/semigroup/app/Main.hs
 create mode 100644 Haskell-book/15/semigroup/package.yaml
 create mode 100644 Haskell-book/15/semigroup/src/Bool.hs
 create mode 100644 Haskell-book/15/semigroup/src/Combine.hs
 create mode 100644 Haskell-book/15/semigroup/src/Comp.hs
 create mode 100644 Haskell-book/15/semigroup/src/Identity.hs
 create mode 100644 Haskell-book/15/semigroup/src/Mem.hs
 create mode 100644 Haskell-book/15/semigroup/src/Or.hs
 create mode 100644 Haskell-book/15/semigroup/src/Trivial.hs
 create mode 100644 Haskell-book/15/semigroup/src/Two.hs
 create mode 100644 Haskell-book/15/semigroup/src/Validation.hs
 create mode 100644 Haskell-book/15/semigroup/stack.yaml
 create mode 100644 Haskell-book/15/semigroup/test/Main.hs
 create mode 100644 Haskell-book/16/Exercises.hs
 create mode 100644 Haskell-book/16/HeavyLifting.hs
 create mode 100644 Haskell-book/16/Possibly.hs
 create mode 100644 Haskell-book/16/Short.hs
 create mode 100644 Haskell-book/16/func/.gitignore
 create mode 100644 Haskell-book/16/func/Setup.hs
 create mode 100644 Haskell-book/16/func/app/Main.hs
 create mode 100644 Haskell-book/16/func/package.yaml
 create mode 100644 Haskell-book/16/func/src/Func.hs
 create mode 100644 Haskell-book/16/func/stack.yaml
 create mode 100644 Haskell-book/16/func/test/Spec.hs
 create mode 100644 Haskell-book/17/Combinations.hs
 create mode 100644 Haskell-book/17/Constant.hs
 create mode 100644 Haskell-book/17/Exercises/.gitignore
 create mode 100644 Haskell-book/17/Exercises/Setup.hs
 create mode 100644 Haskell-book/17/Exercises/app/Main.hs
 create mode 100644 Haskell-book/17/Exercises/package.yaml
 create mode 100644 Haskell-book/17/Exercises/src/Exercises.hs
 create mode 100644 Haskell-book/17/Exercises/stack.yaml
 create mode 100644 Haskell-book/17/Exercises/test/Spec.hs
 create mode 100644 Haskell-book/17/FixerUpper.hs
 create mode 100644 Haskell-book/17/Identity.hs
 create mode 100644 Haskell-book/17/ListApplicative/.gitignore
 create mode 100644 Haskell-book/17/ListApplicative/Setup.hs
 create mode 100644 Haskell-book/17/ListApplicative/app/Main.hs
 create mode 100644 Haskell-book/17/ListApplicative/package.yaml
 create mode 100644 Haskell-book/17/ListApplicative/src/List.hs
 create mode 100644 Haskell-book/17/ListApplicative/src/Validation.hs
 create mode 100644 Haskell-book/17/ListApplicative/src/ZipList.hs
 create mode 100644 Haskell-book/17/ListApplicative/stack.yaml
 create mode 100644 Haskell-book/17/ListApplicative/test/Spec.hs
 create mode 100644 Haskell-book/18/Bind.hs
 create mode 100644 Haskell-book/18/Functions.hs
 create mode 100644 Haskell-book/18/Instance/.gitignore
 create mode 100644 Haskell-book/18/Instance/Setup.hs
 create mode 100644 Haskell-book/18/Instance/package.yaml
 create mode 100644 Haskell-book/18/Instance/src/Identity.hs
 create mode 100644 Haskell-book/18/Instance/src/List.hs
 create mode 100644 Haskell-book/18/Instance/src/Nope.hs
 create mode 100644 Haskell-book/18/Instance/src/PhhhbbtttEither.hs
 create mode 100644 Haskell-book/18/Instance/src/Sum.hs
 create mode 100644 Haskell-book/18/Instance/stack.yaml
 create mode 100644 Haskell-book/18/Instance/test/Spec.hs
 create mode 100644 Haskell-book/19/shawty/.gitignore
 create mode 100644 Haskell-book/19/shawty/ChangeLog.md
 create mode 100644 Haskell-book/19/shawty/LICENSE
 create mode 100644 Haskell-book/19/shawty/README.md
 create mode 100644 Haskell-book/19/shawty/Setup.hs
 create mode 100644 Haskell-book/19/shawty/app/Main.hs
 create mode 100644 Haskell-book/19/shawty/package.yaml
 create mode 100644 Haskell-book/19/shawty/stack.yaml
 create mode 100644 Haskell-book/19/shawty/test/Spec.hs
 create mode 100644 Haskell-book/20/Exercises.hs
 create mode 100644 Haskell-book/20/LibraryFunctions.hs
 create mode 100644 Haskell-book/21/instances/.gitignore
 create mode 100644 Haskell-book/21/instances/LICENSE
 create mode 100644 Haskell-book/21/instances/Setup.hs
 create mode 100644 Haskell-book/21/instances/package.yaml
 create mode 100644 Haskell-book/21/instances/src/Lib.hs
 create mode 100644 Haskell-book/21/instances/src/SkiFree.hs
 create mode 100644 Haskell-book/21/instances/src/Tree.hs
 create mode 100644 Haskell-book/21/instances/stack.yaml
 create mode 100644 Haskell-book/21/instances/test/Spec.hs
 create mode 100644 Haskell-book/22/Ash.hs
 create mode 100644 Haskell-book/22/Reader.hs
 create mode 100644 Haskell-book/22/ReaderPractice.hs
 create mode 100644 Haskell-book/22/WarmingUp.hs
 create mode 100644 Haskell-book/23/FizzBuzz.hs
 create mode 100644 Haskell-book/23/Moi.hs
 create mode 100644 Haskell-book/23/RandomExample/.gitignore
 create mode 100644 Haskell-book/23/RandomExample/LICENSE
 create mode 100644 Haskell-book/23/RandomExample/Setup.hs
 create mode 100644 Haskell-book/23/RandomExample/app/Main.hs
 create mode 100644 Haskell-book/23/RandomExample/package.yaml
 create mode 100644 Haskell-book/23/RandomExample/src/RandomExample.hs
 create mode 100644 Haskell-book/23/RandomExample/src/RandomExample2.hs
 create mode 100644 Haskell-book/23/RandomExample/stack.yaml
 create mode 100644 Haskell-book/23/RandomExample/test/Spec.hs
 create mode 100644 Haskell-book/24/LearnParsers/.gitignore
 create mode 100644 Haskell-book/24/LearnParsers/ChangeLog.md
 create mode 100644 Haskell-book/24/LearnParsers/Setup.hs
 create mode 100644 Haskell-book/24/LearnParsers/app/Main.hs
 create mode 100644 Haskell-book/24/LearnParsers/package.yaml
 create mode 100644 Haskell-book/24/LearnParsers/src/LearnParsers.hs
 create mode 100644 Haskell-book/24/LearnParsers/src/Text/Fractions.hs
 create mode 100644 Haskell-book/24/LearnParsers/stack.yaml
 create mode 100644 Haskell-book/24/ParserExercises/.gitignore
 create mode 100644 Haskell-book/24/ParserExercises/Setup.hs
 create mode 100644 Haskell-book/24/ParserExercises/package.yaml
 create mode 100644 Haskell-book/24/ParserExercises/src/Base10Integer.hs
 create mode 100644 Haskell-book/24/ParserExercises/src/IPAddress.hs
 create mode 100644 Haskell-book/24/ParserExercises/src/LogParser.hs
 create mode 100644 Haskell-book/24/ParserExercises/src/PhoneNumber.hs
 create mode 100644 Haskell-book/24/ParserExercises/src/SemVer.hs
 create mode 100644 Haskell-book/24/ParserExercises/stack.yaml
 create mode 100644 Haskell-book/24/ParserExercises/test/LogTest/Main.hs
 create mode 100644 Haskell-book/24/ParserExercises/test/Spec/Main.hs
 create mode 100644 Haskell-book/24/language-dot/LICENSE
 create mode 100644 Haskell-book/24/language-dot/Setup.hs
 create mode 100644 Haskell-book/24/language-dot/language-dot.cabal
 create mode 100644 Haskell-book/24/language-dot/src/Language/Dot.hs
 create mode 100644 Haskell-book/24/language-dot/src/Language/Dot/Parser.hs
 create mode 100644 Haskell-book/24/language-dot/src/Language/Dot/Pretty.hs
 create mode 100644 Haskell-book/24/language-dot/src/Language/Dot/Syntax.hs
 create mode 100644 Haskell-book/24/language-dot/src/ppdot.hs
 create mode 100644 Haskell-book/24/language-dot/src/test.hs
 create mode 100644 Haskell-book/25/Bifunctor/.gitignore
 create mode 100644 Haskell-book/25/Bifunctor/Setup.hs
 create mode 100644 Haskell-book/25/Bifunctor/package.yaml
 create mode 100644 Haskell-book/25/Bifunctor/src/Bifunctor.hs
 create mode 100644 Haskell-book/25/Bifunctor/stack.yaml
 create mode 100644 Haskell-book/25/Bifunctor/test/Spec.hs
 create mode 100644 Haskell-book/25/Twinplicative/.gitignore
 create mode 100644 Haskell-book/25/Twinplicative/LICENSE
 create mode 100644 Haskell-book/25/Twinplicative/Setup.hs
 create mode 100644 Haskell-book/25/Twinplicative/package.yaml
 create mode 100644 Haskell-book/25/Twinplicative/src/Twinplicative.hs
 create mode 100644 Haskell-book/25/Twinplicative/stack.yaml
 create mode 100644 Haskell-book/26/Embedded/Embedded.cabal
 create mode 100644 Haskell-book/26/Embedded/Setup.hs
 create mode 100644 Haskell-book/26/Embedded/package.yaml
 create mode 100644 Haskell-book/26/Embedded/src/OuterInner.hs
 create mode 100644 Haskell-book/26/Embedded/stack.yaml
 create mode 100644 Haskell-book/26/Embedded/test/Spec.hs
 create mode 100644 Haskell-book/26/Exercises/.gitignore
 create mode 100644 Haskell-book/26/Exercises/Setup.hs
 create mode 100644 Haskell-book/26/Exercises/app/Main.hs
 create mode 100644 Haskell-book/26/Exercises/package.yaml
 create mode 100644 Haskell-book/26/Exercises/src/Exercises.hs
 create mode 100644 Haskell-book/26/Exercises/src/Fix.hs
 create mode 100644 Haskell-book/26/Exercises/stack.yaml
 create mode 100644 Haskell-book/26/Exercises/test/Spec.hs
 create mode 100644 Haskell-book/26/MaybeT/.gitignore
 create mode 100644 Haskell-book/26/MaybeT/Setup.hs
 create mode 100644 Haskell-book/26/MaybeT/package.yaml
 create mode 100644 Haskell-book/26/MaybeT/src/Either.hs
 create mode 100644 Haskell-book/26/MaybeT/src/Identity.hs
 create mode 100644 Haskell-book/26/MaybeT/src/Maybe.hs
 create mode 100644 Haskell-book/26/MaybeT/src/MonadIO.hs
 create mode 100644 Haskell-book/26/MaybeT/src/MonadTrans.hs
 create mode 100644 Haskell-book/26/MaybeT/src/Reader.hs
 create mode 100644 Haskell-book/26/MaybeT/src/State.hs
 create mode 100644 Haskell-book/26/MaybeT/stack.yaml
 create mode 100644 Haskell-book/26/MaybeT/test/Spec.hs
 create mode 100644 Haskell-book/26/Morra/.gitignore
 create mode 100644 Haskell-book/26/Morra/Setup.hs
 create mode 100644 Haskell-book/26/Morra/app/Main.hs
 create mode 100644 Haskell-book/26/Morra/package.yaml
 create mode 100644 Haskell-book/26/Morra/stack.yaml
 create mode 100644 Haskell-book/27/BottomExpression.hs
 create mode 100644 Haskell-book/27/StrictList.hs
 create mode 100644 Haskell-book/28/Bench/.gitignore
 create mode 100644 Haskell-book/28/Bench/Setup.hs
 create mode 100644 Haskell-book/28/Bench/app/Main.hs
 create mode 100644 Haskell-book/28/Bench/package.yaml
 create mode 100644 Haskell-book/28/Bench/stack.yaml
 create mode 100644 Haskell-book/28/DifferenceList/.gitignore
 create mode 100644 Haskell-book/28/DifferenceList/Setup.hs
 create mode 100644 Haskell-book/28/DifferenceList/app/Main.hs
 create mode 100644 Haskell-book/28/DifferenceList/package.yaml
 create mode 100644 Haskell-book/28/DifferenceList/src/Data/DList.hs
 create mode 100644 Haskell-book/28/DifferenceList/src/Data/Queue.hs
 create mode 100644 Haskell-book/28/DifferenceList/stack.yaml
 create mode 100644 Haskell-book/28/DifferenceList/test/Spec.hs

diff --git a/Haskell-book/12/Exercises.hs b/Haskell-book/12/Exercises.hs
new file mode 100644
index 0000000..73b81ba
--- /dev/null
+++ b/Haskell-book/12/Exercises.hs
@@ -0,0 +1,202 @@
+module Exercises where
+
+import Data.List
+
+--
+-- 1
+--
+notThe :: String -> Maybe String
+notThe x
+  | x == "the" = Nothing
+  | otherwise = Just x
+
+replaceThe :: String -> String
+replaceThe x = unwords $ map f (words x)
+    where f = f' . notThe
+          f' (Nothing) = "a"
+          f' (Just y)  = y
+
+isVowel :: Char -> Bool
+isVowel c
+  | c == 'a'  = True
+  | c == 'e'  = True
+  | c == 'i'  = True
+  | c == 'o'  = True
+  | c == 'u'  = True
+  | otherwise = False
+
+--
+-- 2
+--
+countTheBeforeVowel :: String -> Integer
+countTheBeforeVowel n = f False (words n)
+    where f _ []     = 0
+          f v (x:xs)
+            | x == "the" = f True xs
+            | v == True = (if isVowel (head x) then 1 else 0) + (f False xs)
+            | otherwise = f False xs
+
+--
+-- 3
+--
+countVowels :: String -> Integer
+countVowels s = fromIntegral $ length $ filter isVowel s
+
+--
+-- Validate the word
+--
+newtype Word' = Word' String deriving (Show, Eq)
+
+vowels :: String
+vowels = "aeiou"
+
+mkWord :: String -> Maybe Word'
+mkWord w = if (countVowels w) > (div (fromIntegral $ length w) 2)
+           then Nothing
+           else Just (Word' w)
+
+--
+-- It's only Natural
+--
+data Nat = Zero | Succ Nat deriving (Eq, Show)
+
+natToInteger :: Nat -> Integer
+natToInteger Zero = 0
+natToInteger (Succ n) = 1 + natToInteger n
+
+integerToNat :: Integer -> Maybe Nat
+integerToNat n
+  | n < 0     = Nothing
+  | n == 0    = Just Zero
+  | otherwise = Just (f n)
+      where f 0 = Zero
+            f n = Succ (f (n - 1))
+
+--
+-- Small library for Maybe
+--
+--
+-- 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   = v
+mayybee v f (Just x) = f x
+
+--
+-- 3
+--
+fromMaybe :: a -> Maybe a -> a
+fromMaybe x Nothing  = x
+fromMaybe _ (Just x) = x
+
+--
+-- 4
+--
+listToMaybe :: [a] -> Maybe a
+listToMaybe [] = Nothing
+listToMaybe (x:xs) = Just x
+
+maybeToList :: Maybe a -> [a]
+maybeToList Nothing = []
+maybeToList (Just x) = [x]
+
+catMaybes :: [Maybe a] -> [a]
+catMaybes = foldr f []
+    where f Nothing xs = xs
+          f (Just x) xs = x : xs
+
+flipMaybe :: [Maybe a] -> Maybe [a]
+flipMaybe x = if (length x) == (length y) then (Just y) else Nothing
+    where y = catMaybes x
+
+lefts' :: [Either a b] -> [a]
+lefts' = foldr f []
+    where f (Left x) xs = x : xs
+          f _ xs = xs
+
+rights' :: [Either a b] -> [b]
+rights' = foldr f []
+    where f (Right x) xs = x : xs
+          f _ xs = xs
+
+partitionEithers' :: [Either a b] -> ([a], [b])
+partitionEithers' n = (lefts' n, rights' n)
+
+eitherMaybe' :: (b -> c) -> Either a b -> Maybe c
+eitherMaybe' _ (Left x) = Nothing
+eitherMaybe' f (Right x) = Just $ f x
+
+either' :: (a -> c) -> (b -> c) -> Either a b -> c
+either' f _ (Left x) = f x
+either' _ f (Right x) = f x
+
+eitherMaybe'' :: (b -> c) -> Either a b -> Maybe c
+eitherMaybe'' f = either' (\_ -> Nothing) (\x -> Just $ f x)
+
+--
+-- Unfolds
+--
+mehSum :: Num a => [a] -> a
+mehSum xs = go 0 xs
+    where go :: Num a => a -> [a] -> a
+          go n [] = n
+          go n (x:xs) = (go (n + x) xs)
+
+niceSum :: Num a => [a] -> a
+niceSum = foldl' (+) 0
+
+mehProduct :: Num a => [a] -> a
+mehProduct xs = go 1 xs
+    where go :: Num a => a -> [a] -> a
+          go n [] = n
+          go n (x:xs) = (go (n*x) xs)
+
+niceProduct :: Num a => [a] -> a
+niceProduct = foldl' (*) 1
+
+mehConcat :: [[a]] -> [a]
+mehConcat xs = go [] xs
+    where go :: [a] -> [[a]] -> [a]
+          go xs' [] = xs'
+          go xs' (x:xs) = (go (xs' ++ x) xs)
+
+niceConcat :: [[a]] -> [a]
+niceConcat = foldr (++) []
+
+myIterate :: (a -> a) -> a -> [a]
+myIterate f x = go x
+    where go x = x : (go (f x))
+
+myUnfoldr :: (b -> Maybe (a, b)) -> b -> [a]
+myUnfoldr f x = g (f x)
+    where g Nothing = []
+          g (Just (x, y)) = x : g (f y)
+
+betterIterate :: (a -> a) -> a -> [a]
+betterIterate f x = myUnfoldr (\y -> Just (y, f y)) x
+
+data BinaryTree a = Leaf
+                  | Node (BinaryTree a) a (BinaryTree a)
+                  deriving (Eq, Show)
+
+unfold :: (a -> Maybe (a, b, a)) -> a -> BinaryTree b
+unfold f x = g (f x)
+    where g Nothing = Leaf
+          g (Maybe (m, n, o)) = Node (BinaryTree m) n (BinaryTree o)
+
+treeBuild :: Integer -> BinaryTree Integer
+treeBuild = unfold f
+    where f n
+          | n <= 0 = Nothing
+          | otherwise = Just (k - 1, n, k - 1)
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
diff --git a/Haskell-book/13/Cipher.hs b/Haskell-book/13/Cipher.hs
new file mode 100644
index 0000000..55dc7c4
--- /dev/null
+++ b/Haskell-book/13/Cipher.hs
@@ -0,0 +1,16 @@
+module Cipher where
+
+import Data.Char
+import Data.List
+
+vigenere :: String -> String
+vigenere = f (cycle [0, 11, 11, 24])
+    where f _      []       = []
+          f ys     (' ':xs) = ' ' : (f ys xs)
+          f (y:ys) (x:xs)   = (decode (x, y)) : (f ys xs)
+              where decode (x, y) = chr ((mod ((ord x) - 65 + y) 26) + 65)
+
+main :: IO ()
+main = do
+    i <- getLine
+    putStrLn $ vigenere i
diff --git a/Haskell-book/13/Palindrome.hs b/Haskell-book/13/Palindrome.hs
new file mode 100644
index 0000000..439c980
--- /dev/null
+++ b/Haskell-book/13/Palindrome.hs
@@ -0,0 +1,20 @@
+module Palindrome where
+
+import Control.Monad
+import Data.Char
+import System.Exit
+
+format :: String -> String
+format s = filter (\x -> x >= 'a' && x <= 'z') (map toLower s)
+
+palindrome :: IO ()
+palindrome = forever $ do
+    line1 <- getLine
+    case ((format line1) == (format $ reverse line1)) of
+      True -> putStrLn "It's a palindrome!"
+      False -> do
+          putStrLn "Nope!"
+          exitSuccess
+
+main :: IO ()
+main = palindrome
diff --git a/Haskell-book/13/Person.hs b/Haskell-book/13/Person.hs
new file mode 100644
index 0000000..c104a53
--- /dev/null
+++ b/Haskell-book/13/Person.hs
@@ -0,0 +1,34 @@
+module Person where
+
+type Name = String
+type Age = Integer
+
+data Person = Person Name Age deriving Show
+
+data PersonInvalid = NameEmpty
+                   | AgeTooLow
+                   | PersonInvalidUnknown String
+                   deriving (Eq, Show)
+
+mkPerson :: Name -> Age -> Either PersonInvalid Person
+mkPerson name age
+  | name /= "" && age > 0 = Right $ Person name age
+  | name == "" = Left NameEmpty
+  | not (age > 0) = Left AgeTooLow
+  | otherwise =
+      Left $ PersonInvalidUnknown $
+          "Name was: " ++ show name ++ " Age was: " ++ show age
+
+showPerson :: Either PersonInvalid Person -> String
+showPerson (Left NameEmpty) = "Name is empty"
+showPerson (Left AgeTooLow) = "Age is too low"
+showPerson (Left (PersonInvalidUnknown e)) = e
+showPerson (Right p) = "Yay! Successfully got a person: " ++ (show p)
+
+gimmePerson :: IO ()
+gimmePerson = do
+    putStr "Enter your name: "
+    name <- getLine
+    putStr "Enter your age: "
+    age <- getLine
+    putStrLn $ showPerson $ mkPerson name (read age)
diff --git a/Haskell-book/14/addition/Addition.hs b/Haskell-book/14/addition/Addition.hs
new file mode 100644
index 0000000..474eecd
--- /dev/null
+++ b/Haskell-book/14/addition/Addition.hs
@@ -0,0 +1,35 @@
+module Addition where
+
+import Test.Hspec
+import Test.QuickCheck
+
+dividedBy :: Integral a => a -> a -> (a, a)
+dividedBy num denom = go num denom 0
+    where go n d count
+            | n < d = (count, n)
+            | otherwise =  go (n - d) d (count + 1)
+
+multiplyBy :: (Ord a, Eq a, Num a) => a -> a -> a
+multiplyBy a b
+    | a == 0 || b == 0 = 0
+    | a > 0 && b > 0   = multiplyBy' a b
+    | a < 0 && b < 0   = multiplyBy' (-a) (-b)
+    | a < 0 && b > 0   = -(multiplyBy' (-a) b)
+    | a > 0 && b < 0   = -(multiplyBy' a (-b))
+    where  multiplyBy' c 1 = c
+           multiplyBy' c d = c + (multiplyBy c (d - 1))
+
+main :: IO ()
+main = hspec $ do
+    describe "Addition" $ do
+        it "15 divided by 3 is 5" $ do
+            dividedBy 15 3 `shouldBe` (5, 0)
+        it "22 divided by 5 is 4 remainder 2" $ do
+            dividedBy 22 5 `shouldBe` (4, 2)
+        it "x + 1 is always greater than x" $ do
+            property $ \x -> x + 1 > (x :: Int)
+    describe "Multiplication" $ do
+        it "15 multiplied by 3 is 45" $ do
+            multiplyBy 15 3 `shouldBe` 45
+        it "22 multiplied by 5 is 110" $ do
+            multiplyBy 22 5 `shouldBe` 110
\ No newline at end of file
diff --git a/Haskell-book/14/addition/LICENSE b/Haskell-book/14/addition/LICENSE
new file mode 100644
index 0000000..6a042c2
--- /dev/null
+++ b/Haskell-book/14/addition/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\ No newline at end of file
diff --git a/Haskell-book/14/addition/README.md b/Haskell-book/14/addition/README.md
new file mode 100644
index 0000000..543097e
--- /dev/null
+++ b/Haskell-book/14/addition/README.md
@@ -0,0 +1 @@
+# addition
diff --git a/Haskell-book/14/addition/Setup.hs b/Haskell-book/14/addition/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/14/addition/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/14/addition/addition.cabal b/Haskell-book/14/addition/addition.cabal
new file mode 100644
index 0000000..1dec256
--- /dev/null
+++ b/Haskell-book/14/addition/addition.cabal
@@ -0,0 +1,17 @@
+name:                addition
+version:             0.1.0.0
+license-file:        LICENSE
+author:              Chicken Little
+maintainer:          sky@isfalling.org
+category:            Text
+build-type:          Simple
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     Addition
+  ghc-options:         -Wall -fwarn-tabs
+  build-depends:       base >= 4.7 && < 5
+                     , hspec
+                     , QuickCheck
+  hs-source-dirs:      .
+  default-language:    Haskell2010
diff --git a/Haskell-book/14/addition/stack.yaml b/Haskell-book/14/addition/stack.yaml
new file mode 100644
index 0000000..9e311c2
--- /dev/null
+++ b/Haskell-book/14/addition/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-9.14
+
+# 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: ">=1.5"
+#
+# 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/14/addition/stack.yaml.lock b/Haskell-book/14/addition/stack.yaml.lock
new file mode 100644
index 0000000..75bf3ab
--- /dev/null
+++ b/Haskell-book/14/addition/stack.yaml.lock
@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/topics/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 9e880f85f76b7f35a2b6edd1af333ce7f7845d47e897c3509ddd18eaa2763779
+    size: 536352
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/9/14.yaml
+  original: lts-9.14
diff --git a/Haskell-book/14/morse/.gitignore b/Haskell-book/14/morse/.gitignore
new file mode 100644
index 0000000..cf4a5cf
--- /dev/null
+++ b/Haskell-book/14/morse/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+morse.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/14/morse/ChangeLog.md b/Haskell-book/14/morse/ChangeLog.md
new file mode 100644
index 0000000..1ae7856
--- /dev/null
+++ b/Haskell-book/14/morse/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for morse
+
+## Unreleased changes
diff --git a/Haskell-book/14/morse/LICENSE b/Haskell-book/14/morse/LICENSE
new file mode 100644
index 0000000..da7b69b
--- /dev/null
+++ b/Haskell-book/14/morse/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2017
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/14/morse/README.md b/Haskell-book/14/morse/README.md
new file mode 100644
index 0000000..8b8c638
--- /dev/null
+++ b/Haskell-book/14/morse/README.md
@@ -0,0 +1 @@
+# morse
diff --git a/Haskell-book/14/morse/Setup.hs b/Haskell-book/14/morse/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/14/morse/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/14/morse/src/Main.hs b/Haskell-book/14/morse/src/Main.hs
new file mode 100644
index 0000000..1f73b90
--- /dev/null
+++ b/Haskell-book/14/morse/src/Main.hs
@@ -0,0 +1,59 @@
+module Main where
+
+import Control.Monad (forever, when)
+import Data.List (intercalate)
+import Data.Traversable (traverse)
+import Morse (stringToMorse, morseToChar)
+import System.Environment (getArgs)
+import System.Exit (exitFailure, exitSuccess)
+import System.IO (hGetLine, hIsEOF, stdin)
+
+convertToMorse :: IO ()
+convertToMorse = forever $ do
+    weAreDone <- hIsEOF stdin
+    when weAreDone exitSuccess
+
+    line <- hGetLine stdin
+    convertLine line
+
+    where convertLine line = do
+            let morse = stringToMorse line
+            case morse of
+                (Just str) -> putStrLn (intercalate " " str)
+                Nothing -> do
+                    putStrLn $ "ERROR: " ++ line
+                    exitFailure
+
+convertFromMorse :: IO ()
+convertFromMorse = forever $ do
+    weAreDone <- hIsEOF stdin
+    when weAreDone exitSuccess
+
+    line <- hGetLine stdin
+    convertLine line
+
+    where
+        convertLine line = do
+            let decoded :: Maybe String
+                decoded = traverse morseToChar (words line)
+
+            case decoded of
+                (Just s) -> putStrLn s
+                Nothing -> do
+                    putStrLn $ "ERROR: " ++ line
+                    exitFailure
+
+main :: IO ()
+main = do
+    mode <- getArgs
+    case mode of
+        [arg] ->
+            case arg of
+                "from" -> convertFromMorse
+                "to" -> convertToMorse
+                _ -> argError
+        _ -> argError
+
+    where argError = do
+            putStrLn "Please specify the first argument as being 'from' or 'to' morse, such as: morse to"
+            exitFailure
\ No newline at end of file
diff --git a/Haskell-book/14/morse/src/Morse.hs b/Haskell-book/14/morse/src/Morse.hs
new file mode 100644
index 0000000..03193e5
--- /dev/null
+++ b/Haskell-book/14/morse/src/Morse.hs
@@ -0,0 +1,68 @@
+module Morse
+       ( Morse
+       , charToMorse
+       , morseToChar
+       , stringToMorse
+       , letterToMorse
+       , morseToLetter
+       ) where
+
+import qualified Data.Map as M
+
+type Morse = String
+
+letterToMorse :: (M.Map Char Morse)
+letterToMorse = M.fromList [
+    ('a', ".-")
+  , ('b', "-...")
+  , ('c', "-.-.")
+  , ('d', "-..")
+  , ('e', ".")
+  , ('f', "..-.")
+  , ('g', "--.")
+  , ('h', "....")
+  , ('i', "..")
+  , ('j', ".---")
+  , ('k', "-.-")
+  , ('l', ".-..")
+  , ('m', "--")
+  , ('n', "-.")
+  , ('o', "---")
+  , ('p', ".--.")
+  , ('q', "--.-")
+  , ('r', ".-.")
+  , ('s', "...")
+  , ('t', "-")
+  , ('u', "..-")
+  , ('v', "...-")
+  , ('w', ".--")
+  , ('x', "-..-")
+  , ('y', "-.--")
+  , ('z', "--..")
+  , ('1', ".----")
+  , ('2', "..---")
+  , ('3', "...--")
+  , ('4', "....-")
+  , ('5', ".....")
+  , ('6', "-....")
+  , ('7', "--...")
+  , ('8', "---..")
+  , ('9', "----.")
+  , ('0', "-----")
+  ]
+
+morseToLetter :: M.Map Morse Char
+morseToLetter =
+    M.foldWithKey (flip M.insert) M.empty
+                  letterToMorse
+
+charToMorse :: Char -> Maybe Morse
+charToMorse c =
+    M.lookup c letterToMorse
+
+stringToMorse :: String -> Maybe [Morse]
+stringToMorse s =
+    sequence $ fmap charToMorse s
+
+morseToChar :: Morse -> Maybe Char
+morseToChar m = M.lookup m morseToLetter
\ No newline at end of file
diff --git a/Haskell-book/14/morse/src/WordNumber.hs b/Haskell-book/14/morse/src/WordNumber.hs
new file mode 100644
index 0000000..5b25ee2
--- /dev/null
+++ b/Haskell-book/14/morse/src/WordNumber.hs
@@ -0,0 +1,26 @@
+module WordNumber where
+
+import Data.List (unfoldr, intercalate)
+import Data.Maybe (Maybe(..))
+
+digitToWord :: Int -> String
+digitToWord 0 = "zero"
+digitToWord 1 = "one"
+digitToWord 2 = "two"
+digitToWord 3 = "three"
+digitToWord 4 = "four"
+digitToWord 5 = "five" 
+digitToWord 6 = "six"
+digitToWord 7 = "seven"
+digitToWord 8 = "eight"
+digitToWord 9 = "nine"
+digitToWord _ = ""
+
+digits :: Int -> [Int]
+digits n = reverse $ unfoldr unfold n
+    where unfold x
+                | x == 0    = Nothing
+                | otherwise = Just ((mod x 10), (div x 10))
+
+wordNumber :: Int -> String
+wordNumber n = intercalate "-" $ map digitToWord (digits n)
\ No newline at end of file
diff --git a/Haskell-book/14/morse/stack.yaml b/Haskell-book/14/morse/stack.yaml
new file mode 100644
index 0000000..22e3463
--- /dev/null
+++ b/Haskell-book/14/morse/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-9.17
+
+# 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/14/morse/stack.yaml.lock b/Haskell-book/14/morse/stack.yaml.lock
new file mode 100644
index 0000000..6ee2e72
--- /dev/null
+++ b/Haskell-book/14/morse/stack.yaml.lock
@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/topics/lock_files
+
+packages: []
+snapshots:
+- completed:
+    sha256: 82ff94eacdc32a857e5aec82268644fdc3d5bfca07692ceeeb97e2d8ce5726ef
+    size: 535915
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/9/17.yaml
+  original: lts-9.17
diff --git a/Haskell-book/14/morse/tests/CoArbitrary.hs b/Haskell-book/14/morse/tests/CoArbitrary.hs
new file mode 100644
index 0000000..dc0da3d
--- /dev/null
+++ b/Haskell-book/14/morse/tests/CoArbitrary.hs
@@ -0,0 +1,16 @@
+{-# LANGUAGE DeriveGeneric #-}
+
+module CoArbitrary where
+
+import GHC.Generics
+import Test.QuickCheck
+
+data Bool' = True' | False' deriving (Generic)
+
+instance CoArbitrary Bool'
+
+trueGen :: Gen Int
+trueGen = coarbitrary True' arbitrary
+
+falseGen :: Gen Int
+falseGen = coarbitrary False' arbitrary
\ No newline at end of file
diff --git a/Haskell-book/14/morse/tests/WordNumberTest.hs b/Haskell-book/14/morse/tests/WordNumberTest.hs
new file mode 100644
index 0000000..d9623a9
--- /dev/null
+++ b/Haskell-book/14/morse/tests/WordNumberTest.hs
@@ -0,0 +1,24 @@
+module Main where
+
+import Test.Hspec
+import WordNumber (digitToWord, digits, wordNumber)
+
+main :: IO ()
+main = hspec $ do
+    describe "digitToWord" $ do
+        it "returns zero for 0" $ do
+            digitToWord 0 `shouldBe`"zero"
+        it "returns one for 1" $ do
+            digitToWord 1 `shouldBe` "one"
+
+    describe "digits" $ do
+        it "returns [1] for 1" $ do
+            digits 1 `shouldBe` [1]
+        it "returns [1, 0, 0] for 100" $ do
+            digits 100 `shouldBe` [1, 0, 0]
+
+    describe "wordNumber" $ do
+        it "one-zero-zero given 100" $ do
+            wordNumber 100 `shouldBe` "one-zero-zero"
+        it "nine-zero-zero-one for 9001" $ do
+            wordNumber 9001 `shouldBe` "nine-zero-zero-one"
\ No newline at end of file
diff --git a/Haskell-book/14/morse/tests/tests.hs b/Haskell-book/14/morse/tests/tests.hs
new file mode 100644
index 0000000..b27d3b3
--- /dev/null
+++ b/Haskell-book/14/morse/tests/tests.hs
@@ -0,0 +1,86 @@
+module Main where
+
+import qualified Data.Map as M
+import Morse
+import Test.QuickCheck
+import Test.QuickCheck.Gen (oneof)
+
+allowedChars :: [Char]
+allowedChars = M.keys letterToMorse
+
+allowedMorse :: [Morse]
+allowedMorse = M.elems letterToMorse
+
+charGen :: Gen Char
+charGen = elements allowedChars
+
+morseGen :: Gen Morse
+morseGen = elements allowedMorse
+
+prop_thereAndBackAgain :: Property
+prop_thereAndBackAgain =
+    forAll charGen (\c -> ((charToMorse c) >>= morseToChar) == Just c)
+
+main' :: IO ()
+main' = quickCheck prop_thereAndBackAgain
+
+data Trivial = Trivial deriving (Eq, Show)
+
+trivialGen :: Gen Trivial
+trivialGen = return Trivial
+
+instance Arbitrary Trivial where
+    arbitrary = trivialGen
+
+main :: IO ()
+main = do
+    sample trivialGen
+
+data Identity a = Identity a deriving (Eq, Show)
+
+identityGen :: Arbitrary a => Gen (Identity a)
+identityGen = do
+    a <- arbitrary
+    return (Identity a)
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = identityGen
+
+identityGenInt :: Gen (Identity Int)
+identityGenInt = identityGen
+
+data Pair a b = Pair a b deriving (Eq, Show)
+
+pairGen :: (Arbitrary a, Arbitrary b) => Gen (Pair a b)
+pairGen = do
+    a <- arbitrary
+    b <- arbitrary
+    return (Pair a b)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Pair a b) where
+    arbitrary = pairGen
+
+pairGenIntString :: Gen (Pair Int String)
+pairGenIntString = pairGen
+
+data Sum a b = First a | Second b deriving (Eq, Show)
+
+sumGenEqual :: Gen (Sum Char Int)
+sumGenEqual = do
+    a <- arbitrary
+    b <- arbitrary
+    oneof [return $ First a,
+           return $ Second b]
+
+sumGenCharInt :: Gen (Sum Char Int)
+sumGenCharInt = sumGenEqual
+
+sumGenFirstPls :: (Arbitrary a, Arbitrary b) => Gen (Sum a b)
+sumGenFirstPls = do
+    a <- arbitrary
+    b <- arbitrary
+    frequency [(10, return $ First a),
+               (1, return $ Second b)]
+
+sumGenCharIntFirst :: Gen (Sum Char Int)
+sumGenCharIntFirst = sumGenFirstPls
\ No newline at end of file
diff --git a/Haskell-book/14/qc/qc.cabal b/Haskell-book/14/qc/qc.cabal
new file mode 100644
index 0000000..f0b5b3a
--- /dev/null
+++ b/Haskell-book/14/qc/qc.cabal
@@ -0,0 +1,32 @@
+name:           qc
+version:        0.1.0.0
+author:         Eugen Wissner
+maintainer:     belka@caraus.de
+category:       Math
+build-type:     Simple
+cabal-version:  >= 1.10
+
+library
+  hs-source-dirs: src
+  build-depends: base >= 4.7 && < 5
+               , QuickCheck
+  exposed-modules: UsingQuickCheck
+  ghc-options: -Wall
+  default-language: Haskell2010
+
+test-suite tests
+  type: exitcode-stdio-1.0
+  main-is: UsingQuickCheckTest.hs
+  hs-source-dirs: tests
+  ghc-options: -Wall
+  build-depends: base >= 4.7 && < 5
+               , QuickCheck
+               , qc
+
+test-suite idempotence
+  type: exitcode-stdio-1.0
+  main-is: Idempotence.hs
+  hs-source-dirs: tests
+  ghc-options: -Wall
+  build-depends: base >= 4.7 && < 5
+               , QuickCheck
\ No newline at end of file
diff --git a/Haskell-book/14/qc/src/UsingQuickCheck.hs b/Haskell-book/14/qc/src/UsingQuickCheck.hs
new file mode 100644
index 0000000..f0fa27f
--- /dev/null
+++ b/Haskell-book/14/qc/src/UsingQuickCheck.hs
@@ -0,0 +1,58 @@
+module UsingQuickCheck where
+
+import Test.QuickCheck
+
+--
+-- 1
+--
+half :: (Eq a, Fractional a) => a -> a
+half x = x / 2
+
+halfIdentity :: (Eq a, Fractional a) => a -> a
+halfIdentity = (*2) . half
+
+--
+-- 2
+--
+-- for any list you apply sort to
+-- this property should hold
+listOrdered :: (Ord a) => [a] -> Bool
+listOrdered xs =
+    snd $ foldr go (Nothing, True) xs
+    where go _ status@(_, False) = status
+          go y (Nothing, t) = (Just y, t)
+          go y (Just x, _) = (Just y, x >= y)
+
+--
+-- 3
+--
+plusAssociative :: (Ord a, Integral a) => a -> a -> a -> Bool
+plusAssociative x y z = x + (y + z) == (x + y) + z
+
+plusCommutative :: (Ord a, Integral a) => a -> a -> Bool
+plusCommutative x y = x + y == y + x
+
+--
+-- 4
+--
+mulAssociative :: (Ord a, Integral a) => a -> a -> a -> Bool
+mulAssociative x y z = x * (y * z) == (x * y) * z
+
+mulCommutative :: (Ord a, Integral a) => a -> a -> Bool
+mulCommutative x y = x * y == y * x
+
+data Fool = Fulse
+          | Frue
+          deriving (Eq, Show)
+
+data Fool' = Fulse' -- 2/3
+           | Frue'  -- 1/3
+           deriving (Eq, Show)
+
+instance Arbitrary Fool where
+    arbitrary = oneof [ return Fulse
+                      , return Frue ]
+
+instance Arbitrary Fool' where
+    arbitrary = frequency [ (3, return Fulse')
+                          , (1, return Frue')]
\ No newline at end of file
diff --git a/Haskell-book/14/qc/stack.yaml b/Haskell-book/14/qc/stack.yaml
new file mode 100644
index 0000000..22e3463
--- /dev/null
+++ b/Haskell-book/14/qc/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-9.17
+
+# 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/14/qc/tests/Idempotence.hs b/Haskell-book/14/qc/tests/Idempotence.hs
new file mode 100644
index 0000000..4b484d0
--- /dev/null
+++ b/Haskell-book/14/qc/tests/Idempotence.hs
@@ -0,0 +1,30 @@
+module Main where
+
+import Data.Char
+import Data.List
+import Test.QuickCheck
+
+capitalizeWord :: String -> String
+capitalizeWord [] = []
+capitalizeWord (x:xs) = toUpper x : xs
+
+twice :: (a -> a) -> (a -> a)
+twice y = y . y
+
+fourTimes :: (a -> a) -> (a -> a)
+fourTimes = twice . twice
+
+f :: String -> Bool
+f x = 
+    (capitalizeWord x == twice capitalizeWord x)
+    && (capitalizeWord x == fourTimes capitalizeWord x)
+
+f' :: Ord a => [a] -> Bool
+f' x =
+    (sort x == twice sort x)
+    && (sort x == fourTimes sort x)
+
+main :: IO ()
+main = do
+    quickCheck f
+    quickCheck (f' :: String -> Bool)
\ No newline at end of file
diff --git a/Haskell-book/14/qc/tests/UsingQuickCheckTest.hs b/Haskell-book/14/qc/tests/UsingQuickCheckTest.hs
new file mode 100644
index 0000000..da5ddb5
--- /dev/null
+++ b/Haskell-book/14/qc/tests/UsingQuickCheckTest.hs
@@ -0,0 +1,128 @@
+module Main where
+
+import Data.List (sort)
+import UsingQuickCheck
+import Test.QuickCheck
+
+prop_half :: (Eq a, Fractional a) => a -> Bool
+prop_half x = (halfIdentity x) == x
+
+associativeGen :: (Integer -> Integer -> Integer -> Bool) -> Gen Bool
+associativeGen f = do
+    x <- (arbitrary :: Gen Integer)
+    y <- (arbitrary :: Gen Integer)
+    z <- (arbitrary :: Gen Integer)
+    elements [f x y z]
+
+commutativeGen :: (Integer -> Integer -> Bool) -> Gen Bool
+commutativeGen f = do
+    x <- (arbitrary :: Gen Integer)
+    y <- (arbitrary :: Gen Integer)
+    elements [f x y]
+
+assocNotNegGen :: (Int -> Int -> Int -> Bool) -> Gen Bool
+assocNotNegGen f = do
+    x <- choose (1 :: Int, 100)
+    y <- choose (1 :: Int, 100)
+    z <- choose (1 :: Int, 100)
+    elements [f x y z]
+
+commutNotNegGen :: (Int -> Int -> Bool) -> Gen Bool
+commutNotNegGen f = do
+    x <- choose (1 :: Int, 100)
+    y <- choose (1 :: Int, 100)
+    elements [f x y]
+    
+
+prop_quotRem :: Property
+prop_quotRem =
+    forAll (prop_quotRem') (\(x ,y) -> (quot x y) * y + (rem x y) == x)
+    where prop_quotRem' = do
+          x <- choose (1 :: Int, 10000)
+          y <- choose (1 :: Int, 10000)
+          return (x, y)
+
+prop_divMod :: Property
+prop_divMod =
+    forAll (prop_divMod') (\(x ,y) -> (div x y) * y + (mod x y) == x)
+    where prop_divMod' = do
+          x <- choose (1 :: Int, 10000)
+          y <- choose (1 :: Int, 10000)
+          return (x, y)
+
+prop_reverse :: Property
+prop_reverse =
+    forAll prop_reverse' (\xs -> (reverse . reverse) xs == id xs)
+    where prop_reverse' = do
+          x <- (arbitrary :: Gen [Integer])
+          return x
+
+prop_dollar :: Property
+prop_dollar =
+    forAll prop_dollar' (\x -> x)
+    where prop_dollar' = do
+          x <- (arbitrary :: Gen Integer)
+          return ((id $ x) == (id x))
+
+prop_point :: Property
+prop_point =
+    forAll prop_point' (\x -> x)
+    where prop_point' = do
+          x <- (arbitrary :: Gen Integer)
+          let pointFunc = negate . id
+          let appliedFunc = \y -> negate (id y)
+          return (pointFunc x == appliedFunc x)
+
+prop_foldr1 :: Property
+prop_foldr1 =
+    forAll prop_foldr1' (\x -> x)
+    where prop_foldr1' = do
+          x <- (arbitrary :: Gen [Integer])
+          y <- (arbitrary :: Gen [Integer])
+          return ((foldr (:) x y) == (x ++ y))
+
+prop_foldr2 :: Property
+prop_foldr2 =
+    forAll prop_foldr2' (\x -> x)
+    where prop_foldr2' = do
+          x <- (arbitrary :: Gen [[Integer]])
+          return ((foldr (++) [] x) == (concat x))
+
+prop_length :: Property
+prop_length =
+    forAll prop_length' (\x -> x)
+    where prop_length' = do
+          n <- (arbitrary :: Gen Int)
+          xs <- (arbitrary :: Gen [Integer])
+          return ((length (take n xs)) == n)
+
+prop_readShow :: Property
+prop_readShow =
+    forAll prop_readShow' (\x -> x)
+    where prop_readShow' = do
+          x <- (arbitrary :: Gen Integer)
+          return ((read (show x)) == x)
+
+main :: IO ()
+main = do
+    quickCheck (prop_half :: Double -> Bool)
+    quickCheck $ (listOrdered :: [Int] -> Bool) . sort
+    
+    quickCheck $ associativeGen plusAssociative
+    quickCheck $ commutativeGen plusCommutative
+    quickCheck $ associativeGen mulAssociative
+    quickCheck $ commutativeGen mulCommutative
+
+    quickCheck prop_quotRem
+    quickCheck prop_divMod
+
+    quickCheck $ assocNotNegGen (\x y z -> x ^ (y ^ z) == (x ^ y) ^ z)
+    quickCheck $ commutNotNegGen (\x y -> x ^ y == y ^ x)
+
+    quickCheck prop_reverse
+    quickCheck prop_dollar
+    quickCheck prop_point
+    quickCheck prop_foldr1
+    quickCheck prop_foldr2
+    quickCheck prop_length
+    quickCheck prop_readShow
\ No newline at end of file
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)
diff --git a/Haskell-book/16/Exercises.hs b/Haskell-book/16/Exercises.hs
new file mode 100644
index 0000000..f07b7ea
--- /dev/null
+++ b/Haskell-book/16/Exercises.hs
@@ -0,0 +1,154 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE GADTs #-}
+module Exercises where
+
+-- Rearrange.
+--
+-- 1
+--
+data Sum a b =
+    First b
+  | Second a
+
+instance Functor (Sum e) where
+    fmap f (First a) = First (f a)
+    fmap f (Second b) = Second b
+
+--
+-- 2
+--
+data Company a c b =
+    DeepBlue a c
+  | Something b
+
+instance Functor (Company e e') where
+    fmap f (Something b) = Something (f b)
+    fmap _ (DeepBlue a c) = DeepBlue a c
+
+--
+-- 3
+--
+data More b a =
+    L a b a
+  | R b a b
+  deriving (Eq, Show)
+
+instance Functor (More x) where
+    fmap f (L a b a') = L (f a) b (f a')
+    fmap f (R b a b') = R b (f a) b'
+
+-- Write Functor instances.
+--
+-- 1
+--
+data Quant a b =
+    Finance
+  | Desk a
+  | Bloor b
+
+instance Functor (Quant a) where
+    fmap f (Bloor b) = Bloor (f b)
+    fmap _ Finance = Finance
+    fmap _ (Desk x) = Desk x
+
+--
+-- 2
+--
+newtype K a b =
+    K a
+
+instance Functor (K a) where
+    fmap _ (K x) = K x
+
+--
+-- 3
+--
+newtype Flip f a b =
+    Flip (f b a)
+    deriving (Eq, Show)
+
+instance Functor (Flip K a) where
+    fmap f (Flip (K a))= Flip $ K $ f a
+
+--
+-- 4
+--
+data EvilGoateeConst a b =
+    GoatyConst b
+
+instance Functor (EvilGoateeConst a) where
+    fmap f (GoatyConst x) = GoatyConst $ f x
+
+--
+-- 5
+--
+data LiftItOut f a = LiftItOut (f a)
+
+instance Functor f => Functor (LiftItOut f) where
+    fmap f (LiftItOut g) = LiftItOut $ fmap f $ g
+
+--
+-- 6
+--
+data Parappa f g a =
+    DaWrappa (f a) (g a)
+
+instance (Functor f, Functor g) => Functor (Parappa f g) where
+    fmap f (DaWrappa f1 f2) = DaWrappa (fmap f f1) (fmap f f2)
+
+--
+-- 7
+--
+data IgnoreOne f g a b =
+    IgnoringSomething (f a) (g b)
+
+instance Functor g => Functor (IgnoreOne f g a) where
+    fmap f (IgnoringSomething f1 f2) = IgnoringSomething f1 $ fmap f f2
+
+--
+-- 8
+--
+data Notorious g o a t =
+    Notorious (g o) (g a) (g t)
+
+instance Functor g => Functor (Notorious g o a) where
+    fmap f (Notorious f1 f2 f3) = Notorious f1 f2 $ fmap f f3
+
+--
+-- 9
+--
+data List a = Nil | Cons a (List a)
+
+instance Functor List where
+    fmap f (Cons x y) = Cons (f x) (fmap f y)
+    fmap _ Nil = Nil
+
+--
+-- 10
+--
+data GoatLord a =
+    NoGoat
+  | OneGoat a
+  | MoreGoats (GoatLord a)
+              (GoatLord a)
+              (GoatLord a)
+
+instance Functor GoatLord where
+    fmap _ NoGoat = NoGoat
+    fmap f (OneGoat x) = OneGoat $ f x
+    fmap f (MoreGoats x y z) = MoreGoats (g x) (g y) (g z)
+        where g t = fmap f t
+
+--
+-- 11
+--
+data TalkToMe a =
+    Halt
+  | Print String a
+  | Read (String -> a)
+
+instance Functor TalkToMe where
+    fmap _ Halt = Halt
+    fmap f (Print x y) = Print x $ f y
+    fmap f (Read g) = Read (f . g)
diff --git a/Haskell-book/16/HeavyLifting.hs b/Haskell-book/16/HeavyLifting.hs
new file mode 100644
index 0000000..e92f875
--- /dev/null
+++ b/Haskell-book/16/HeavyLifting.hs
@@ -0,0 +1,16 @@
+module HeavyLifting where
+
+a = fmap (+1) $ read "[1]" :: [Int]
+
+b = (fmap . fmap) (++ "lol") (Just ["Hi,", "Hello"])
+
+c = fmap (*2) (\x -> x - 2)
+
+d =
+    fmap ((return '1' ++) . show)
+    (\x -> [x, 1..3])
+
+e :: IO Integer
+e = let ioi = readIO "1" :: IO Integer
+        changed = fmap read $ fmap ("123" ++) $ fmap show ioi
+     in fmap (*3) changed
diff --git a/Haskell-book/16/Possibly.hs b/Haskell-book/16/Possibly.hs
new file mode 100644
index 0000000..bf92540
--- /dev/null
+++ b/Haskell-book/16/Possibly.hs
@@ -0,0 +1,10 @@
+module Possibly where
+
+data Possibly a =
+    LolNope
+  | Yeppers a
+  deriving (Eq, Show)
+
+instance Functor Possibly where
+    fmap f LolNope = LolNope
+    fmap f (Yeppers x) = Yeppers $ f x
diff --git a/Haskell-book/16/Short.hs b/Haskell-book/16/Short.hs
new file mode 100644
index 0000000..f6ecd66
--- /dev/null
+++ b/Haskell-book/16/Short.hs
@@ -0,0 +1,10 @@
+module Short where
+
+data Sum a b =
+    First a
+  | Second b
+  deriving (Eq, Show)
+
+instance Functor (Sum a) where
+    fmap f (Second x) = Second $ f x
+    fmap f (First x) = First x
diff --git a/Haskell-book/16/func/.gitignore b/Haskell-book/16/func/.gitignore
new file mode 100644
index 0000000..d1d1f0a
--- /dev/null
+++ b/Haskell-book/16/func/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+func.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/16/func/Setup.hs b/Haskell-book/16/func/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/16/func/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/16/func/app/Main.hs b/Haskell-book/16/func/app/Main.hs
new file mode 100644
index 0000000..de1c1ab
--- /dev/null
+++ b/Haskell-book/16/func/app/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import Lib
+
+main :: IO ()
+main = someFunc
diff --git a/Haskell-book/16/func/package.yaml b/Haskell-book/16/func/package.yaml
new file mode 100644
index 0000000..9595fb3
--- /dev/null
+++ b/Haskell-book/16/func/package.yaml
@@ -0,0 +1,34 @@
+name:                func
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- QuickCheck
+
+library:
+  source-dirs: src
+
+# executables:
+#  func-exe:
+#    main:                Main.hs
+#    source-dirs:         app
+#    ghc-options:
+#    - -threaded
+#    - -rtsopts
+#    - -with-rtsopts=-N
+#    dependencies:
+#    - func
+
+tests:
+  func-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - func
diff --git a/Haskell-book/16/func/src/Func.hs b/Haskell-book/16/func/src/Func.hs
new file mode 100644
index 0000000..920ab80
--- /dev/null
+++ b/Haskell-book/16/func/src/Func.hs
@@ -0,0 +1,89 @@
+module Func where
+
+import Test.QuickCheck
+
+-- class Functor f where
+--     fmap :: (a -> b) -> f a -> f b
+
+newtype Identity a = Identity a deriving (Eq, Show)
+
+instance Functor Identity where
+    fmap f (Identity a) = Identity $ f a
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = fmap Identity arbitrary
+
+data Pair a = Pair a a deriving (Eq, Show)
+
+instance Functor Pair where
+    fmap f (Pair x y) = Pair (f x) (f y)
+
+instance Arbitrary a => Arbitrary (Pair a) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Pair x y
+
+data Two a b = Two a b deriving (Eq, Show)
+
+instance Functor (Two a) where
+    fmap f (Two x y) = Two x (f y)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Two a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Two x y
+
+data Three a b c = Three a b c deriving (Eq, Show)
+
+instance Functor (Three a b) where
+    fmap f (Three x y z) = Three x y (f z)
+
+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
+
+data Three' a b = Three' a b b deriving (Eq, Show)
+
+instance Functor (Three' a) where
+    fmap f (Three' x y z) = Three' x (f y) (f z)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Three' a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        return $ Three' x y z
+
+data Four a b c d = Four a b c d deriving (Eq, Show)
+
+instance Functor (Four a b c) where
+    fmap f (Four x y z t) = Four x y z (f t)
+
+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
+
+data Four' a b = Four' a a a b deriving (Eq, Show)
+
+instance Functor (Four' a) where
+    fmap f (Four' x y z t) = Four' x y z (f t)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Four' a b) where
+      arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        t <- arbitrary
+        return $ Four' x y z t
+
+data Trivial = Trivial
diff --git a/Haskell-book/16/func/stack.yaml b/Haskell-book/16/func/stack.yaml
new file mode 100644
index 0000000..005cfcf
--- /dev/null
+++ b/Haskell-book/16/func/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-10.3
+
+# 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/16/func/test/Spec.hs b/Haskell-book/16/func/test/Spec.hs
new file mode 100644
index 0000000..14de325
--- /dev/null
+++ b/Haskell-book/16/func/test/Spec.hs
@@ -0,0 +1,54 @@
+{-# LANGUAGE ViewPatterns #-}
+
+import Func
+import Test.QuickCheck
+import Test.QuickCheck.Function
+
+functorIdentity :: (Functor f, Eq (f a)) => f a -> Bool
+functorIdentity f = fmap id f == f
+
+functorCompose :: (Eq (f c), Functor f) =>
+       (a -> b)
+    -> (b -> c)
+    -> f a
+    -> Bool
+functorCompose f g x =
+    (fmap g (fmap f x)) == (fmap (g . f) x)
+
+functorCompose' :: (Eq (f c), Functor f) =>
+        f a
+    -> Fun a b
+    -> Fun b c
+    -> Bool
+functorCompose' x (Fun _ f) (Fun _ g) =
+    (fmap (g . f) x) == (fmap g . fmap f $ x)
+
+main :: IO ()
+main = do
+    quickCheck (functorIdentity :: Identity Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Identity Int -> Bool)
+    quickCheck (functorCompose' :: Identity Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Pair Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Pair Int -> Bool)
+    quickCheck (functorCompose' :: Pair Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Two Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Two Int Int -> Bool)
+    quickCheck (functorCompose' :: Two Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Three Int Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Three Int Int Int -> Bool)
+    quickCheck (functorCompose' :: Three Int Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Three' Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Three' Int Int -> Bool)
+    quickCheck (functorCompose' :: Three' Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Four Int Int Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Four Int Int Int Int -> Bool)
+    quickCheck (functorCompose' :: Four Int Int Int Int -> Fun Int Int -> Fun Int Int -> Bool)
+
+    quickCheck (functorIdentity :: Four' Int Int -> Bool)
+    quickCheck ((functorCompose (+1) (*2)) :: Four' Int Int -> Bool)
+    quickCheck (functorCompose' :: Four' Int Int -> Fun Int Int -> Fun Int Int -> Bool)
diff --git a/Haskell-book/17/Combinations.hs b/Haskell-book/17/Combinations.hs
new file mode 100644
index 0000000..9e13e1e
--- /dev/null
+++ b/Haskell-book/17/Combinations.hs
@@ -0,0 +1,12 @@
+module Combinations where
+
+import Control.Applicative (liftA3)
+
+stops :: String
+stops = "pbtdkg"
+
+vowels :: String
+vowels = "aeiou"
+
+combos :: [a] -> [b] -> [c] -> [(a, b, c)]
+combos = liftA3 (\x y z -> (x, y, z))
diff --git a/Haskell-book/17/Constant.hs b/Haskell-book/17/Constant.hs
new file mode 100644
index 0000000..f25da54
--- /dev/null
+++ b/Haskell-book/17/Constant.hs
@@ -0,0 +1,13 @@
+module Constant where
+
+newtype Constant a b =
+    Constant { getConstant :: a }
+    deriving (Eq, Ord, Show)
+
+instance Functor (Constant a) where
+    fmap _ (Constant x) = Constant x
+
+instance Monoid a
+  => Applicative (Constant a) where
+      pure x = Constant mempty
+      (Constant x) <*> (Constant y) = Constant $ mappend x y
diff --git a/Haskell-book/17/Exercises/.gitignore b/Haskell-book/17/Exercises/.gitignore
new file mode 100644
index 0000000..3834f98
--- /dev/null
+++ b/Haskell-book/17/Exercises/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Exercises.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/17/Exercises/Setup.hs b/Haskell-book/17/Exercises/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/17/Exercises/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/17/Exercises/app/Main.hs b/Haskell-book/17/Exercises/app/Main.hs
new file mode 100644
index 0000000..43979f0
--- /dev/null
+++ b/Haskell-book/17/Exercises/app/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import Exercises
+
+main :: IO ()
+main = return ()
diff --git a/Haskell-book/17/Exercises/package.yaml b/Haskell-book/17/Exercises/package.yaml
new file mode 100644
index 0000000..f7e3630
--- /dev/null
+++ b/Haskell-book/17/Exercises/package.yaml
@@ -0,0 +1,35 @@
+name:                Exercises
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- QuickCheck
+- checkers
+
+library:
+  source-dirs: src
+
+executables:
+  Exercises-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Exercises
+
+tests:
+  Exercises-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Exercises
diff --git a/Haskell-book/17/Exercises/src/Exercises.hs b/Haskell-book/17/Exercises/src/Exercises.hs
new file mode 100644
index 0000000..1ea70e3
--- /dev/null
+++ b/Haskell-book/17/Exercises/src/Exercises.hs
@@ -0,0 +1,124 @@
+module Exercises where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+--- 1
+data Pair a = Pair a a deriving (Show, Eq)
+
+instance Functor Pair where
+    fmap f (Pair x y) = Pair (f x) (f y)
+
+instance Applicative Pair where
+    pure f = Pair f f
+    (Pair f f') <*> (Pair x y) = Pair (f x) (f' y)
+
+instance Arbitrary a => Arbitrary (Pair a) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Pair x y
+
+instance Eq a => EqProp (Pair a) where
+    (=-=) = eq
+
+--- 2
+data Two a b  = Two a b deriving (Show, Eq)
+
+instance Functor (Two a) where
+    fmap f (Two x y) = Two x (f y)
+
+instance Monoid a => Applicative (Two a) where
+    pure x = Two mempty $ x
+    (Two f f') <*> (Two x y) = Two (mappend f x) (f' y)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Two a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Two x y
+
+instance (Eq a, Eq b) => EqProp (Two a b) where
+    (=-=) = eq
+
+--- 3
+data Three a b c  = Three a b c deriving (Show, Eq)
+
+instance Functor (Three a b) where
+    fmap f (Three x y z) = Three x y (f z)
+
+instance (Monoid a, Monoid b) => Applicative (Three a b) where
+    pure x = Three mempty mempty x
+    (Three f f' f'') <*> (Three x y z) = Three (mappend f x) (mappend f' y) (f'' z)
+
+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 (Eq a, Eq b, Eq c) => EqProp (Three a b c) where
+    (=-=) = eq
+
+--- 4
+data Three' a b = Three' a b b deriving (Show, Eq)
+
+instance Functor (Three' a) where
+    fmap f (Three' x y z) = Three' x (f y) (f z)
+
+instance (Monoid a) => Applicative (Three' a) where
+    pure x = Three' mempty x x
+    (Three' f f' f'') <*> (Three' x y z) = Three' (mappend f x) (f' y) (f'' z)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Three' a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        return $ Three' x y z
+
+instance (Eq a, Eq b) => EqProp (Three' a b) where
+    (=-=) = eq
+
+--- 5
+data Four a b c d = Four a b c d deriving (Show, Eq)
+
+instance Functor (Four a b c) where
+    fmap f (Four x y z t) = Four x y z (f t)
+
+instance (Monoid a, Monoid b, Monoid c) => Applicative (Four a b c) where
+    pure x = Four mempty mempty mempty x
+    (Four f f' f'' f''') <*> (Four x y z t) = Four (mappend f x) (mappend f' y) (mappend f'' z) (f''' t)
+
+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
+
+instance (Eq a, Eq b, Eq c, Eq d) => EqProp (Four a b c d) where
+    (=-=) = eq
+
+--- 5
+data Four' a b = Four' a a a b deriving (Show, Eq)
+
+instance Functor (Four' a) where
+    fmap f (Four' x y z t) = Four' x y z (f t)
+
+instance (Monoid a) => Applicative (Four' a) where
+    pure x = Four' mempty mempty mempty x
+    (Four' f f' f'' f''') <*> (Four' x y z t) = Four' (mappend f x) (mappend f' y) (mappend f'' z) (f''' t)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Four' a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        t <- arbitrary
+        return $ Four' x y z t
+
+instance (Eq a, Eq b) => EqProp (Four' a b) where
+    (=-=) = eq
diff --git a/Haskell-book/17/Exercises/stack.yaml b/Haskell-book/17/Exercises/stack.yaml
new file mode 100644
index 0000000..005cfcf
--- /dev/null
+++ b/Haskell-book/17/Exercises/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-10.3
+
+# 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/17/Exercises/test/Spec.hs b/Haskell-book/17/Exercises/test/Spec.hs
new file mode 100644
index 0000000..e1405c5
--- /dev/null
+++ b/Haskell-book/17/Exercises/test/Spec.hs
@@ -0,0 +1,26 @@
+import Data.Monoid
+import Exercises
+import Test.QuickCheck.Checkers
+import Test.QuickCheck.Classes
+
+main :: IO ()
+main = do
+    quickBatch $ functor $ Pair ('a', 'b', 'c') ('d', 'e', 'f')
+    quickBatch $ applicative $ Pair ('a', 'b', 'c') ('d', 'e', 'f')
+    quickBatch $ functor $ Two ('a', 'b', 'c') (1 :: Integer, 2 :: Integer, 3 :: Integer)
+    quickBatch $ applicative $ Two (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                   (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer))
+    quickBatch $ applicative $ Three (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                     (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer))
+                                     (Sum (4 :: Integer), Sum (5 :: Integer), Sum (6 :: Integer))
+    quickBatch $ applicative $ Three' (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                      (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer))
+                                      (Sum (4 :: Integer), Sum (5 :: Integer), Sum (6 :: Integer))
+    quickBatch $ applicative $ Four (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                    (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                    (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer))
+                                    (Sum (4 :: Integer), Sum (5 :: Integer), Sum (6 :: Integer))
+    quickBatch $ applicative $ Four (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                    (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                    (Product (1 :: Integer), Product (2 :: Integer), Product (3 :: Integer))
+                                    (Sum (4 :: Integer), Sum (5 :: Integer), Sum (6 :: Integer))
diff --git a/Haskell-book/17/FixerUpper.hs b/Haskell-book/17/FixerUpper.hs
new file mode 100644
index 0000000..b09877f
--- /dev/null
+++ b/Haskell-book/17/FixerUpper.hs
@@ -0,0 +1,6 @@
+module FixerUpper where
+
+a = const <$> Just <$> "Hello" <*> "World"
+
+b = (,,,) <$> Just 90
+    <*> Just 10 <*> Just "Tierness" <*> pure [1, 2, 3]
diff --git a/Haskell-book/17/Identity.hs b/Haskell-book/17/Identity.hs
new file mode 100644
index 0000000..6b5f9a9
--- /dev/null
+++ b/Haskell-book/17/Identity.hs
@@ -0,0 +1,9 @@
+newtype Identity a = Identity a
+    deriving (Eq, Show, Ord)
+
+instance Functor Identity where
+    fmap f (Identity x) = Identity $ f x
+
+instance Applicative Identity where
+    pure x = Identity x
+    (Identity f) <*> (Identity y) = Identity $ f y
diff --git a/Haskell-book/17/ListApplicative/.gitignore b/Haskell-book/17/ListApplicative/.gitignore
new file mode 100644
index 0000000..296aa3a
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+ListApplicative.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/17/ListApplicative/Setup.hs b/Haskell-book/17/ListApplicative/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/17/ListApplicative/app/Main.hs b/Haskell-book/17/ListApplicative/app/Main.hs
new file mode 100644
index 0000000..66f0611
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/app/Main.hs
@@ -0,0 +1,6 @@
+module Main where
+
+import List
+
+main :: IO ()
+main = return ()
diff --git a/Haskell-book/17/ListApplicative/package.yaml b/Haskell-book/17/ListApplicative/package.yaml
new file mode 100644
index 0000000..5cfefdf
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/package.yaml
@@ -0,0 +1,35 @@
+name:                ListApplicative
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- QuickCheck
+- checkers
+
+library:
+  source-dirs: src
+
+executables:
+  ListApplicative-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - ListApplicative
+
+tests:
+  ListApplicative-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - ListApplicative
diff --git a/Haskell-book/17/ListApplicative/src/List.hs b/Haskell-book/17/ListApplicative/src/List.hs
new file mode 100644
index 0000000..92cf8b9
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/src/List.hs
@@ -0,0 +1,46 @@
+module List where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data List a =
+    Nil
+  | Cons a (List a)
+  deriving (Eq, Show)
+
+instance Functor List where
+    fmap _ Nil = Nil
+    fmap f (Cons x y) = Cons (f x) (fmap f y)
+
+instance Applicative List where
+    pure f = Cons f Nil
+    Nil <*> _ = Nil
+    _ <*> Nil = Nil
+    f <*> x = flatMap (\f' -> fmap f' x) f
+
+append :: List a -> List a -> List a
+append Nil ys = ys
+append (Cons x xs) ys = Cons x $ xs `append` ys
+
+fold :: (a -> b -> b) -> b -> List a -> b
+fold _ b Nil = b
+fold f b (Cons h t) = f h (fold f b t)
+
+concat' :: List (List a) -> List a
+concat' = fold append Nil
+
+flatMap :: (a -> List b) -> List a -> List b
+flatMap f as = concat' $ fmap f as
+
+append' :: List a -> a -> List a
+append' acc x = Cons x acc
+
+fromList :: [a] -> List a
+fromList xs = foldl (\l a -> Cons a l) Nil xs
+
+instance Arbitrary a => Arbitrary (List a) where
+    arbitrary = frequency [(1, pure Nil),
+                           (5, Cons <$> arbitrary <*> arbitrary)]
+
+instance Eq a => EqProp (List a) where
+    (=-=) = eq
diff --git a/Haskell-book/17/ListApplicative/src/Validation.hs b/Haskell-book/17/ListApplicative/src/Validation.hs
new file mode 100644
index 0000000..5ee3e9b
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/src/Validation.hs
@@ -0,0 +1,27 @@
+module Validation where
+
+import Test.QuickCheck (Arbitrary(..), frequency)
+import Test.QuickCheck.Checkers
+
+data Validation e a =
+    Failure e
+  | Success a
+  deriving (Eq, Show)
+
+instance Functor (Validation e) where
+    fmap f (Success x) = Success $ f x
+    fmap f (Failure x) = Failure x
+
+instance Monoid e => Applicative (Validation e) where
+    pure = Success
+    (Failure x) <*> (Success _) = Failure x
+    (Success _) <*> (Failure x) = Failure x
+    (Failure f) <*> (Failure y) = Failure $ mappend f y
+    (Success f) <*> (Success y) = Success $ f y
+
+instance (Arbitrary a, Arbitrary e) => Arbitrary (Validation e a) where
+    arbitrary = frequency [(1, Failure <$> arbitrary),
+                           (5, Success <$> arbitrary)]
+
+instance (Eq a, Eq e) => EqProp (Validation e a) where
+    (=-=) = eq
diff --git a/Haskell-book/17/ListApplicative/src/ZipList.hs b/Haskell-book/17/ListApplicative/src/ZipList.hs
new file mode 100644
index 0000000..e36ec33
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/src/ZipList.hs
@@ -0,0 +1,40 @@
+module ZipList where
+
+import Control.Applicative
+import List
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+take' :: Int -> List a -> List a
+take' _ Nil = Nil
+take' 0 _ = Nil
+take' n (Cons x xs) = Cons x $ take' (n - 1) xs
+
+newtype ZipList' a =
+    ZipList' (List a)
+    deriving (Eq, Show)
+
+instance Eq a => EqProp (ZipList' a) where
+    xs =-= ys = xs' `eq` ys'
+        where xs' = let (ZipList' l) = xs
+                     in take' 3000 l
+              ys' = let (ZipList' l) = ys
+                     in take' 3000 l
+
+instance Functor ZipList' where
+    fmap f (ZipList' xs) = ZipList' $ fmap f xs
+
+instance Monoid a => Monoid (ZipList' a) where
+    mempty = pure mempty
+    mappend = liftA2 mappend
+
+instance Applicative ZipList' where
+    pure f = ZipList' $ repeat
+        where repeat = Cons f repeat 
+    (ZipList' fs) <*> (ZipList' xs) = ZipList' $ applicative fs xs
+        where applicative Nil _ = Nil
+              applicative _ Nil = Nil
+              applicative (Cons f fs) (Cons x xs) = Cons (f x) $ applicative fs xs
+
+instance Arbitrary a => Arbitrary (ZipList' a) where
+    arbitrary = ZipList' <$> arbitrary
diff --git a/Haskell-book/17/ListApplicative/stack.yaml b/Haskell-book/17/ListApplicative/stack.yaml
new file mode 100644
index 0000000..005cfcf
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/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-10.3
+
+# 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/17/ListApplicative/test/Spec.hs b/Haskell-book/17/ListApplicative/test/Spec.hs
new file mode 100644
index 0000000..ecd8148
--- /dev/null
+++ b/Haskell-book/17/ListApplicative/test/Spec.hs
@@ -0,0 +1,16 @@
+module Main where
+
+import Control.Applicative
+import Data.Monoid
+import Test.QuickCheck.Checkers
+import Test.QuickCheck.Classes
+import List
+import ZipList
+import Validation (Validation(..))
+
+main :: IO ()
+main = do
+    quickBatch $ applicative (Cons (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer)) Nil)
+    quickBatch $ monoid (ZipList' $ Cons (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer)) Nil)
+    quickBatch $ applicative (ZipList' $ Cons (Sum (1 :: Integer), Sum (2 :: Integer), Sum (3 :: Integer)) Nil)
+    quickBatch $ applicative ((Success (Sum 1, Sum 2, Sum 3)) :: Validation String (Sum Integer, Sum Integer, Sum Integer))
diff --git a/Haskell-book/18/Bind.hs b/Haskell-book/18/Bind.hs
new file mode 100644
index 0000000..daeaada
--- /dev/null
+++ b/Haskell-book/18/Bind.hs
@@ -0,0 +1,6 @@
+module Bind where
+
+import Control.Monad
+
+bind :: Monad m => (a -> m b) -> m a -> m b
+bind f x = join $ fmap f x
diff --git a/Haskell-book/18/Functions.hs b/Haskell-book/18/Functions.hs
new file mode 100644
index 0000000..841ecbd
--- /dev/null
+++ b/Haskell-book/18/Functions.hs
@@ -0,0 +1,21 @@
+module Functions where
+
+j :: Monad m => m (m a) -> m a
+j = flip (>>=) id
+
+l1 :: Monad m => (a -> b) -> m a -> m b
+l1 = fmap
+
+l2 :: Monad m => (a -> b -> c) -> m a -> m b -> m c
+l2 f xs ys = f <$> xs <*> ys
+
+a :: Monad m => m a -> m (a -> b) -> m b
+a xs f = f <*> xs
+
+meh :: Monad m => [a] -> (a -> m b) -> m [b]
+meh xs f = rec $ fmap f xs
+    where rec [] = return []
+          rec (x:xs) = (:) <$> x <*> (rec xs)
+
+flipType :: Monad m => [m a] -> m [a]
+flipType = flip meh id
diff --git a/Haskell-book/18/Instance/.gitignore b/Haskell-book/18/Instance/.gitignore
new file mode 100644
index 0000000..01698eb
--- /dev/null
+++ b/Haskell-book/18/Instance/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Instance.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/18/Instance/Setup.hs b/Haskell-book/18/Instance/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/18/Instance/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/18/Instance/package.yaml b/Haskell-book/18/Instance/package.yaml
new file mode 100644
index 0000000..23b61e5
--- /dev/null
+++ b/Haskell-book/18/Instance/package.yaml
@@ -0,0 +1,26 @@
+name:                Instance
+version:             0.1.0.0
+github:              "githubuser/Instance"
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- QuickCheck
+- checkers
+
+library:
+  source-dirs: src
+
+tests:
+  Instance-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Instance
diff --git a/Haskell-book/18/Instance/src/Identity.hs b/Haskell-book/18/Instance/src/Identity.hs
new file mode 100644
index 0000000..13cd1b2
--- /dev/null
+++ b/Haskell-book/18/Instance/src/Identity.hs
@@ -0,0 +1,24 @@
+module Identity where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+newtype Identity a = Identity a
+    deriving (Eq, Ord, Show)
+
+instance Functor Identity where
+    fmap f (Identity x) = Identity $ f x
+
+instance Applicative Identity where
+    pure = Identity
+    (Identity f) <*> x = fmap f x
+
+instance Monad Identity where
+    return = pure
+    (Identity x) >>= f = f x
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = fmap Identity $ arbitrary
+
+instance Eq a => EqProp (Identity a) where
+    (=-=) = eq
diff --git a/Haskell-book/18/Instance/src/List.hs b/Haskell-book/18/Instance/src/List.hs
new file mode 100644
index 0000000..bd3a06b
--- /dev/null
+++ b/Haskell-book/18/Instance/src/List.hs
@@ -0,0 +1,44 @@
+module List where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data List a =
+    Nil
+  | Cons a (List a)
+  deriving (Eq, Show)
+
+instance Functor List where
+    fmap f Nil = Nil
+    fmap f (Cons x xs) = Cons (f x) (fmap f xs)
+
+append :: List a -> List a -> List a
+append Nil ys = ys
+append (Cons x xs) ys = Cons x $ xs `append` ys
+
+fold :: (a -> b -> b) -> b -> List a -> b
+fold _ b Nil = b
+fold f b (Cons h t) = f h (fold f b t)
+
+concat' :: List (List a) -> List a
+concat' = fold append Nil
+
+flatMap :: (a -> List b) -> List a -> List b
+flatMap f as = concat' $ fmap f as
+
+instance Applicative List where
+    pure f = Cons f Nil
+    Nil <*> _ = Nil
+    _ <*> Nil = Nil
+    f <*> x = flatMap (\f' -> fmap f' x) f
+
+instance Monad List where
+    return = pure
+    x >>= f = concat' $ fmap f x
+
+instance Arbitrary a => Arbitrary (List a) where
+    arbitrary = frequency [(1, pure Nil),
+                           (5, Cons <$> arbitrary <*> arbitrary)]
+
+instance Eq a => EqProp (List a) where
+    (=-=) = eq
diff --git a/Haskell-book/18/Instance/src/Nope.hs b/Haskell-book/18/Instance/src/Nope.hs
new file mode 100644
index 0000000..9a7fea1
--- /dev/null
+++ b/Haskell-book/18/Instance/src/Nope.hs
@@ -0,0 +1,23 @@
+module Nope where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data Nope a = NopeDotJpg deriving (Show, Eq)
+
+instance Functor Nope where
+    fmap _ _ = NopeDotJpg
+
+instance Applicative Nope where
+    pure _ = NopeDotJpg
+    _ <*> _ = NopeDotJpg
+
+instance Monad Nope where
+    return _ = NopeDotJpg
+    _ >>= _ = NopeDotJpg
+
+instance Arbitrary (Nope a) where
+    arbitrary = return NopeDotJpg
+
+instance EqProp (Nope a) where
+    (=-=) = eq
diff --git a/Haskell-book/18/Instance/src/PhhhbbtttEither.hs b/Haskell-book/18/Instance/src/PhhhbbtttEither.hs
new file mode 100644
index 0000000..0fc6acc
--- /dev/null
+++ b/Haskell-book/18/Instance/src/PhhhbbtttEither.hs
@@ -0,0 +1,38 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+module PhhhbbtttEither where
+
+import Prelude ( Monad(..)
+               , Functor(..)
+               , Applicative(..)
+               , Eq(..)
+               , ($)
+               , Show(..) )
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data PhhhbbtttEither b a =
+        Left a
+      | Right b
+      deriving (Eq, Show)
+
+instance Functor (PhhhbbtttEither b) where
+    fmap f (Right x) = Right x
+    fmap f (Left x) = Left $ f x
+
+instance Applicative (PhhhbbtttEither b) where
+    pure x = Left x
+    Right f <*> _ = Right f
+    Left f <*> x = fmap f x
+
+instance Monad (PhhhbbtttEither b) where
+    return = pure
+    (Right x) >>= f = Right x
+    (Left x) >>= f = f x
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (PhhhbbtttEither b a) where
+    arbitrary = frequency [ (1, fmap Right arbitrary)
+                          , (1, fmap Left arbitrary)
+                          ]
+
+instance (Eq a, Eq b) => EqProp (PhhhbbtttEither b a) where
+    (=-=) = eq
diff --git a/Haskell-book/18/Instance/src/Sum.hs b/Haskell-book/18/Instance/src/Sum.hs
new file mode 100644
index 0000000..d51b211
--- /dev/null
+++ b/Haskell-book/18/Instance/src/Sum.hs
@@ -0,0 +1,31 @@
+module Sum where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data Sum a b =
+    First a
+  | Second b
+  deriving (Eq, Show)
+
+instance Functor (Sum a) where
+    fmap f (First x) = First x
+    fmap f (Second x) = Second $ f x
+
+instance Applicative (Sum a) where
+    pure x = Second x
+    First f <*> _ = First f
+    Second f <*> x = fmap f x
+
+instance Monad (Sum a) where
+    return = pure
+    (First x) >>= f = First x
+    (Second x) >>= f = f x
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Sum a b) where
+    arbitrary = frequency [ (1, fmap First arbitrary)
+                          , (1, fmap Second arbitrary)
+                          ]
+
+instance (Eq a, Eq b) => EqProp (Sum a b) where
+    (=-=) = eq
diff --git a/Haskell-book/18/Instance/stack.yaml b/Haskell-book/18/Instance/stack.yaml
new file mode 100644
index 0000000..97a175f
--- /dev/null
+++ b/Haskell-book/18/Instance/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-10.4
+
+# 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/18/Instance/test/Spec.hs b/Haskell-book/18/Instance/test/Spec.hs
new file mode 100644
index 0000000..ea250fc
--- /dev/null
+++ b/Haskell-book/18/Instance/test/Spec.hs
@@ -0,0 +1,29 @@
+import Sum
+import Nope
+import qualified PhhhbbtttEither as Phhhbbttt
+import Identity
+import List
+import Test.QuickCheck.Checkers
+import Test.QuickCheck.Classes
+
+main :: IO ()
+main = do
+    quickBatch $ functor $ (First (1, 2, 3) :: Sum (Int, Int, Int) (Int, Int, Int))
+    quickBatch $ applicative $ (First (1, 2, 3) :: Sum (Int, Int, Int) (Int, Int, Int))
+    quickBatch $ monad $ (First (1, 2, 3) :: Sum (Int, Int, Int) (Int, Int, Int))
+
+    quickBatch $ functor $ (NopeDotJpg :: Nope (Int, Int, Int))
+    quickBatch $ applicative $ (NopeDotJpg :: Nope (Int, Int, Int))
+    quickBatch $ monad $ (NopeDotJpg :: Nope (Int, Int, Int))
+
+    quickBatch $ functor $ (Phhhbbttt.Left (1, 2, 3) :: Phhhbbttt.PhhhbbtttEither (Int, Int, Int) (Int, Int, Int))
+    quickBatch $ applicative $ (Phhhbbttt.Left (1, 2, 3) :: Phhhbbttt.PhhhbbtttEither (Int, Int, Int) (Int, Int, Int))
+    quickBatch $ monad $ (Phhhbbttt.Left (1, 2, 3) :: Phhhbbttt.PhhhbbtttEither (Int, Int, Int) (Int, Int, Int))
+
+    quickBatch $ functor $ (Identity (1, 2, 3) :: Identity (Int, Int, Int))
+    quickBatch $ applicative $ (Identity (1, 2, 3) :: Identity (Int, Int, Int))
+    quickBatch $ monad $ (Identity (1, 2, 3) :: Identity (Int, Int, Int))
+
+    quickBatch $ functor (Cons (1 :: Integer, 2 :: Integer, 3 :: Integer) Nil)
+    quickBatch $ applicative (Cons (1 :: Integer, 2 :: Integer, 3 :: Integer) Nil)
+    quickBatch $ monad (Cons (1 :: Integer, 2 :: Integer, 3 :: Integer) Nil)
diff --git a/Haskell-book/19/shawty/.gitignore b/Haskell-book/19/shawty/.gitignore
new file mode 100644
index 0000000..16d1698
--- /dev/null
+++ b/Haskell-book/19/shawty/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+shawty.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/19/shawty/ChangeLog.md b/Haskell-book/19/shawty/ChangeLog.md
new file mode 100644
index 0000000..2ab2f20
--- /dev/null
+++ b/Haskell-book/19/shawty/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for shawty
+
+## Unreleased changes
diff --git a/Haskell-book/19/shawty/LICENSE b/Haskell-book/19/shawty/LICENSE
new file mode 100644
index 0000000..e037c72
--- /dev/null
+++ b/Haskell-book/19/shawty/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2018
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/19/shawty/README.md b/Haskell-book/19/shawty/README.md
new file mode 100644
index 0000000..c260578
--- /dev/null
+++ b/Haskell-book/19/shawty/README.md
@@ -0,0 +1 @@
+# shawty
diff --git a/Haskell-book/19/shawty/Setup.hs b/Haskell-book/19/shawty/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/19/shawty/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/19/shawty/app/Main.hs b/Haskell-book/19/shawty/app/Main.hs
new file mode 100644
index 0000000..b8bea2e
--- /dev/null
+++ b/Haskell-book/19/shawty/app/Main.hs
@@ -0,0 +1,107 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main where
+
+import Control.Monad (replicateM)
+import Control.Monad.IO.Class (liftIO)
+import qualified Data.ByteString.Char8 as BC
+import Data.Text.Encoding (decodeUtf8, encodeUtf8)
+import qualified Data.Text.Lazy as TL
+import qualified Database.Redis as R
+import Network.URI (URI, parseURI)
+import qualified System.Random as SR
+import Web.Scotty
+
+alphaNum :: String
+alphaNum = ['A'..'Z'] ++ ['0'..'9']
+
+randomElement :: String -> IO Char
+randomElement xs = do
+    let maxIndex :: Int
+        maxIndex = length xs - 1
+    -- Right of arrow is IO Int,
+    -- so randomDigit is Int
+    randomDigit <- SR.randomRIO (0, maxIndex)
+    return (xs !! randomDigit)
+
+shortyGen :: IO [Char]
+shortyGen =
+    replicateM 7 (randomElement alphaNum)
+
+saveURI :: R.Connection
+        -> BC.ByteString
+        -> BC.ByteString
+        -> IO (Either R.Reply R.Status)
+saveURI conn shortURI uri = R.runRedis conn $ R.set shortURI uri
+
+getURI :: R.Connection
+       -> BC.ByteString
+       -> IO (Either R.Reply (Maybe BC.ByteString))
+getURI conn shortURI = R.runRedis conn $ R.get shortURI
+
+linkShorty :: String -> String
+linkShorty shorty =
+    concat
+    [ "<a href=\""
+    , shorty
+    , "\">Copy and paste your short URL</a>"
+    ]
+
+-- TL.concat :: [TL.Text] -> TL.Text
+shortyCreated :: Show a
+              => a
+              -> String
+              -> TL.Text
+shortyCreated resp shawty =
+    TL.concat [ TL.pack (show resp)
+              , " shorty is: "
+              , TL.pack (linkShorty shawty)
+              ]
+
+shortyAintUri :: TL.Text -> TL.Text
+shortyAintUri uri =
+    TL.concat
+    [ uri
+    , " wasn't a url,"
+    , " did you forget http://?"
+    ]
+
+shortyFound :: TL.Text -> TL.Text
+shortyFound tbs =
+    TL.concat
+    [ "<a href=\""
+    , tbs, "\">"
+    , tbs, "</a>"
+    ]
+
+app :: R.Connection
+    -> ScottyM ()
+app rConn = do
+    get "/" $ do
+        uri <- param "uri"
+        let parsedUri :: Maybe URI
+            parsedUri = parseURI (TL.unpack uri)
+        case parsedUri of
+          Just _ -> do
+              shawty <- liftIO shortyGen
+              let shorty = BC.pack shawty
+                  uri' = encodeUtf8 (TL.toStrict uri)
+              resp <- liftIO (saveURI rConn shorty uri')
+              html (shortyCreated resp shawty)
+          Nothing -> text (shortyAintUri uri)
+    get "/:short" $ do
+        short <- param "short"
+        uri <- liftIO (getURI rConn short)
+        case uri of
+          Left reply -> text (TL.pack (show reply))
+          Right mbBS -> case mbBS of
+                          Nothing -> text "uri not found"
+                          Just bs -> html (shortyFound tbs)
+                              where tbs :: TL.Text
+                                    tbs = TL.fromStrict (decodeUtf8 bs)
+
+
+main :: IO ()
+main = do
+    rConn <- R.connect R.defaultConnectInfo
+    scotty 3000 (app rConn)
diff --git a/Haskell-book/19/shawty/package.yaml b/Haskell-book/19/shawty/package.yaml
new file mode 100644
index 0000000..ea8e1ab
--- /dev/null
+++ b/Haskell-book/19/shawty/package.yaml
@@ -0,0 +1,31 @@
+name:                shawty
+version:             0.1.0.0
+homepage:            http://github.com
+license:             BSD3
+author:              Chris Allen
+maintainer:          cma@bitemyapp.com
+copyright:           2015, Chris Allen
+build-type:          Simple
+
+synopsis:            URI shortener
+category:            Web
+description:         Please see README.md
+
+dependencies:
+- base >= 4.7 && < 5
+- bytestring
+- hedis
+- mtl
+- network-uri
+- random
+- scotty
+- semigroups
+- text
+- transformers
+
+executables:
+  shawty:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
diff --git a/Haskell-book/19/shawty/stack.yaml b/Haskell-book/19/shawty/stack.yaml
new file mode 100644
index 0000000..97a175f
--- /dev/null
+++ b/Haskell-book/19/shawty/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-10.4
+
+# 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/19/shawty/test/Spec.hs b/Haskell-book/19/shawty/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/Haskell-book/19/shawty/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/Haskell-book/20/Exercises.hs b/Haskell-book/20/Exercises.hs
new file mode 100644
index 0000000..6bab580
--- /dev/null
+++ b/Haskell-book/20/Exercises.hs
@@ -0,0 +1,38 @@
+module Exercises where
+
+-- 1
+data Constant a b = Constant b deriving (Show)
+
+instance Foldable (Constant a) where
+    foldr f acc (Constant x) = f x acc
+
+-- 2
+data Two a b = Two a b deriving (Show)
+
+instance Foldable (Two a) where
+    foldr f acc (Two _ x) = f x acc
+
+-- 3
+data Three a b c = Three a b c deriving (Show)
+
+instance Foldable (Three a b) where
+    foldr f acc (Three _ _ x) = f x acc
+
+-- 4
+data Three' a b = Three' a b b deriving (Show)
+
+instance Foldable (Three' a) where
+    foldr f acc (Three' _ x y) = f y $ f x acc
+
+-- 5
+data Four' a b = Four' a b b b deriving (Show)
+
+instance Foldable (Four' a) where
+    foldr f acc (Four' _ x y z) = f z $ f y $ f x acc
+
+filterF :: ( Applicative f
+           , Foldable t
+           , Monoid (f a))
+        => (a -> Bool) -> t a -> f a
+filterF f x = foldMap y x
+    where y k = if f k then pure k else mempty
diff --git a/Haskell-book/20/LibraryFunctions.hs b/Haskell-book/20/LibraryFunctions.hs
new file mode 100644
index 0000000..412de32
--- /dev/null
+++ b/Haskell-book/20/LibraryFunctions.hs
@@ -0,0 +1,51 @@
+module LibraryFunctions where
+
+-- 1
+sum :: (Foldable t, Num a) => t a -> a
+sum = foldr (+) 0
+
+-- 2
+product :: (Foldable t, Num a) => t a -> a
+product = foldr (*) 0
+
+-- 3
+elem :: (Foldable t, Eq a) => a -> t a -> Bool
+elem needle = foldr (\x b -> b || (needle == x)) False
+
+-- 4
+minimum :: (Foldable t, Ord a) => t a -> Maybe a
+minimum = foldr f Nothing
+    where f x Nothing = Just x
+          f x (Just y)
+            | x > y = Just x
+            | otherwise = Just y
+
+-- 5
+maximum :: (Foldable t, Ord a) => t a -> Maybe a
+maximum = foldr f Nothing
+    where f x Nothing = Just x
+          f x (Just y)
+            | x < y = Just x
+            | otherwise = Just y
+
+-- 6
+null :: (Foldable t) => t a -> Bool
+null f = LibraryFunctions.length f == 0
+
+-- 7
+length :: (Foldable t) => t a -> Int
+length = foldr (\_ l -> l + 1) 0
+
+-- 8
+toList :: (Foldable t) => t a -> [a]
+toList = foldr (:) []
+
+-- 9
+-- | Combine the elements of a structure using a monoid.
+--
+fold :: (Foldable t, Monoid m) => t m -> m
+fold = LibraryFunctions.foldMap id
+
+-- 10
+foldMap :: (Foldable t, Monoid m) => (a -> m) -> t a -> m
+foldMap f t = foldr (\x m -> mappend (f x) m) mempty t
diff --git a/Haskell-book/21/instances/.gitignore b/Haskell-book/21/instances/.gitignore
new file mode 100644
index 0000000..5273565
--- /dev/null
+++ b/Haskell-book/21/instances/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+instances.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/21/instances/LICENSE b/Haskell-book/21/instances/LICENSE
new file mode 100644
index 0000000..e037c72
--- /dev/null
+++ b/Haskell-book/21/instances/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2018
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/21/instances/Setup.hs b/Haskell-book/21/instances/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/21/instances/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/21/instances/package.yaml b/Haskell-book/21/instances/package.yaml
new file mode 100644
index 0000000..11b92bb
--- /dev/null
+++ b/Haskell-book/21/instances/package.yaml
@@ -0,0 +1,24 @@
+name:                instances
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- QuickCheck
+- checkers
+
+library:
+  source-dirs: src
+
+tests:
+  instances-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - instances
diff --git a/Haskell-book/21/instances/src/Lib.hs b/Haskell-book/21/instances/src/Lib.hs
new file mode 100644
index 0000000..1fbb25b
--- /dev/null
+++ b/Haskell-book/21/instances/src/Lib.hs
@@ -0,0 +1,222 @@
+module Lib where
+
+import Data.Monoid
+import Data.Traversable
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+--
+-- Identity
+--
+newtype Identity a = Identity a
+    deriving (Eq, Ord, Show)
+
+instance Functor Identity where
+    fmap f (Identity x) = Identity $ f x
+
+instance Applicative Identity where
+    pure = Identity
+    (Identity f) <*> x = fmap f x
+
+instance Foldable Identity where
+    foldr f acc (Identity x) = f x acc
+
+instance Arbitrary a => Arbitrary (Identity a) where
+    arbitrary = fmap Identity $ arbitrary
+
+instance Eq a => EqProp (Identity a) where
+    (=-=) = eq
+
+instance Traversable Identity where
+    traverse f (Identity x) = Identity <$> f x
+
+--
+-- Constant
+--
+newtype Constant a b = Constant { getConstant :: a }
+    deriving (Eq, Ord, Show)
+
+instance Functor (Constant a) where
+    fmap _ (Constant x) = Constant x
+
+instance Monoid a => Applicative (Constant a) where
+    pure _ = Constant mempty
+    (Constant x) <*> (Constant y) = Constant $ mappend x y
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Constant a b) where
+    arbitrary = do
+        x <- arbitrary
+        return $ Constant x
+
+instance (Eq a, Eq b) => EqProp (Constant a  b) where
+    (=-=) = eq
+
+instance Foldable (Constant a) where
+    foldMap _ (Constant _) = mempty
+
+instance Traversable (Constant a) where
+    traverse f (Constant x) = pure $ Constant x
+
+--
+-- Maybe
+--
+data Optional a = Nada | Yep a deriving (Show, Eq, Ord)
+
+instance Monoid a => Monoid (Optional a) where
+    mempty = Nada
+    mappend Nada _ = Nada
+    mappend _ Nada = Nada
+    mappend (Yep x) (Yep y) = Yep $ mappend x y
+
+instance Applicative Optional where
+    pure = Yep
+    (Yep f) <*> (Yep x) = Yep $ f x
+    Nada <*> (Yep x) = Nada
+    _ <*> Nada = Nada
+
+instance Functor Optional where
+    fmap _ Nada = Nada
+    fmap f (Yep x) = Yep $ f x
+
+instance Foldable Optional where
+    foldr f acc Nada = acc
+    foldr f acc (Yep x) = f x acc
+
+instance Traversable Optional where
+    traverse f Nada = pure Nada
+    traverse f (Yep x) = Yep <$> f x
+
+instance (CoArbitrary a, Arbitrary a) => Arbitrary (Optional a) where
+    arbitrary = do
+        x <- arbitrary
+        frequency [ (1, return Nada)
+                  , (2, return $ Yep x)
+                  ]
+
+instance (Eq a) => EqProp (Optional a) where
+    (=-=) = eq
+
+--
+-- List
+--
+data List a = Nil | Cons a (List a) deriving (Eq, Show)
+
+instance Functor List where
+    fmap _ Nil = Nil
+    fmap f (Cons x xs) = Cons (f x) (fmap f xs)
+
+instance Foldable List where
+    foldr _ acc Nil = acc
+    foldr f acc (Cons x xs) = f x (foldr f acc xs)
+
+instance Traversable List where
+    sequenceA Nil = pure Nil
+    sequenceA (Cons x xs) = Cons <$> x <*> (sequenceA xs)
+
+instance Arbitrary a => Arbitrary (List a) where
+    arbitrary = sized go
+        where go 0 = pure Nil
+              go n = do
+                  xs <- go (n - 1)
+                  x <- arbitrary
+                  return $ Cons x xs
+
+instance (Eq a) => EqProp (List a) where
+    (=-=) = eq
+
+--
+-- Three
+--
+data Three a b c = Three a b c deriving (Show, Eq)
+
+instance Functor (Three a b) where
+    fmap f (Three x y z) = Three x y (f z)
+
+instance Foldable (Three a b) where
+    foldr f acc (Three x y z) = (f z acc)
+
+instance Traversable (Three a b) where
+    traverse f (Three x y z) = fmap (Three x y) (f z)
+
+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 (Eq a, Eq b, Eq c) => EqProp (Three a b c) where
+    (=-=) = eq
+
+--
+-- Pair
+--
+data Pair a b = Pair a b deriving (Eq, Show)
+
+instance Functor (Pair a) where
+    fmap f (Pair x y) = Pair x (f y)
+
+instance Foldable (Pair a) where
+    foldr f acc (Pair x y) = (f y acc)
+
+instance Traversable (Pair a) where
+    traverse f (Pair x y) = fmap (Pair x) (f y)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Pair a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        return $ Pair x y
+
+instance (Eq a, Eq b) => EqProp (Pair a b) where
+    (=-=) = eq
+
+--
+-- Big
+--
+data Big a b = Big a b b deriving (Eq, Show)
+
+instance Functor (Big a) where
+    fmap f (Big x y z) = Big x (f y) (f z)
+
+instance Foldable (Big a) where
+    foldr f acc (Big _ y z) = (f y (f z acc)) 
+
+instance Traversable (Big a) where
+    traverse f (Big x y z) = (Big x) <$> (f y) <*> (f z)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Big a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        return $ Big x y z
+
+instance (Eq a, Eq b) => EqProp (Big a b) where
+    (=-=) = eq
+
+--
+-- Bigger
+--
+data Bigger a b = Bigger a b b b deriving (Eq, Show)
+
+instance Functor (Bigger a) where
+    fmap f (Bigger x y z t) = Bigger x (f y) (f z) (f t)
+
+instance Foldable (Bigger a) where
+    foldr f acc (Bigger _ y z t) = f y $ f z $ f t acc
+
+instance Traversable (Bigger a) where
+    traverse f (Bigger x y z t) = (Bigger x) <$> (f y) <*> (f z) <*> (f t)
+
+instance (Arbitrary a, Arbitrary b) => Arbitrary (Bigger a b) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        t <- arbitrary
+        return $ Bigger x y z t
+
+instance (Eq a, Eq b) => EqProp (Bigger a b) where
+    (=-=) = eq
+
diff --git a/Haskell-book/21/instances/src/SkiFree.hs b/Haskell-book/21/instances/src/SkiFree.hs
new file mode 100644
index 0000000..70e87dc
--- /dev/null
+++ b/Haskell-book/21/instances/src/SkiFree.hs
@@ -0,0 +1,32 @@
+{-# LANGUAGE FlexibleContexts #-}
+
+module SkiFree where
+
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+
+data S n a = S (n a) a deriving (Eq, Show)
+
+instance ( Functor n
+         , Arbitrary (n a)
+         , Arbitrary a)
+  => Arbitrary (S n a) where
+      arbitrary = S <$> arbitrary <*> arbitrary
+
+--instance ( Applicative n
+--         , Testable (n Property)
+--         , EqProp a)
+--  => EqProp (S n a) where
+--    (S x y) =-= (S p q) =
+--        (property $ (=-=) <$> x <*> p) .&. (y =-= q)
+instance (Eq (n a), Eq a) => EqProp (S n a) where
+    (=-=) = eq
+
+instance Functor n => Functor (S n) where
+    fmap f (S x y) = S (fmap f x) (f y)
+
+instance Foldable n => Foldable (S n) where
+    foldMap f (S n a) = mappend (foldMap f n) (f a)
+
+instance Traversable n => Traversable (S n) where
+    traverse f (S x y) = S <$> (traverse f x) <*> (f y)
diff --git a/Haskell-book/21/instances/src/Tree.hs b/Haskell-book/21/instances/src/Tree.hs
new file mode 100644
index 0000000..5c0740c
--- /dev/null
+++ b/Haskell-book/21/instances/src/Tree.hs
@@ -0,0 +1,44 @@
+module Tree where
+
+import Data.Monoid
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+import Test.QuickCheck.Classes
+
+-- Solution:
+-- https://www.reddit.com/r/HaskellBook/comments/7w7bqn/ch_21_is_this_a_sane_instance_of_traversable/
+
+data Tree a = Empty
+            | Leaf a
+            | Node (Tree a) a (Tree a)
+            deriving (Eq, Show)
+
+instance Functor Tree where
+    fmap _ Empty = Empty
+    fmap f (Leaf x) = Leaf $ f x
+    fmap f (Node x y z) = Node (fmap f x) (f y) (fmap f z)
+
+-- foldMap is a bit easier and looks more natural, but you can do
+-- foldr too for extra credit.
+instance Foldable Tree where
+    foldMap _ Empty = mempty
+    foldMap f (Leaf x) = f x
+    foldMap f (Node x y z) = (foldMap f x) <> (f y) <> (foldMap f z)
+
+instance Traversable Tree where
+    traverse f Empty = pure Empty
+    traverse f (Leaf x) = Leaf <$> f x
+    traverse f (Node x y z) = Node <$> (traverse f x) <*> (f y) <*> (traverse f z)
+
+instance Arbitrary a => Arbitrary (Tree a) where
+    arbitrary = do
+        x <- arbitrary
+        y <- arbitrary
+        z <- arbitrary
+        frequency [ (1, return Empty)
+                  , (2, return $ Leaf y)
+                  , (3, return $ Node x y z)
+                  ]
+
+instance Eq a => EqProp (Tree a) where
+    (=-=) = eq
diff --git a/Haskell-book/21/instances/stack.yaml b/Haskell-book/21/instances/stack.yaml
new file mode 100644
index 0000000..35d283a
--- /dev/null
+++ b/Haskell-book/21/instances/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-10.5
+
+# 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/21/instances/test/Spec.hs b/Haskell-book/21/instances/test/Spec.hs
new file mode 100644
index 0000000..934b120
--- /dev/null
+++ b/Haskell-book/21/instances/test/Spec.hs
@@ -0,0 +1,35 @@
+import Lib
+import Data.Monoid
+import Test.QuickCheck
+import Test.QuickCheck.Checkers
+import Test.QuickCheck.Classes
+import SkiFree
+import Tree
+
+main :: IO ()
+main = do
+    sample' (arbitrary :: Gen (S [] Int))
+
+    quickBatch $ traversable $ (Identity (['a'], ['b'], ['c']))
+
+    quickBatch $ applicative $ (undefined :: Constant (String, String, String) (String, String, String))
+    quickBatch $ traversable $ (undefined :: Constant (String, String, String) (String, String, String))
+
+    quickBatch $ traversable $ (undefined :: Optional (String, String, String))
+
+    quickBatch $ traversable $ (undefined :: List (String, String, String))
+
+    quickBatch $ traversable $ (undefined :: Three (String, String, String)
+                                                   (String, String, String)
+                                                   (String, String, String))
+    quickBatch $ traversable $ (undefined :: Pair (String, String, String)
+                                                  (String, String, String))
+    quickBatch $ traversable $ (undefined :: Big (String, String, String)
+                                                 (String, String, String))
+    quickBatch $ traversable $ (undefined :: Bigger (String, String, String)
+                                                    (String, String, String))
+
+    quickBatch $ functor $ S [("a", "q", "y")] ("a", "b", "c")
+    quickBatch $ traversable $ S [("a", "q", "y")] ("a", "b", "c")
+
+    quickBatch $ traversable $ Leaf ("a", "q", "y")
diff --git a/Haskell-book/22/Ash.hs b/Haskell-book/22/Ash.hs
new file mode 100644
index 0000000..d3bf585
--- /dev/null
+++ b/Haskell-book/22/Ash.hs
@@ -0,0 +1,7 @@
+module Ask where
+
+newtype Reader r a =
+    Reader { runReader :: r -> a }
+
+ask :: Reader a a
+ask = Reader id
diff --git a/Haskell-book/22/Reader.hs b/Haskell-book/22/Reader.hs
new file mode 100644
index 0000000..e50b623
--- /dev/null
+++ b/Haskell-book/22/Reader.hs
@@ -0,0 +1,62 @@
+{-# LANGUAGE InstanceSigs #-}
+module Reader where
+
+import Control.Applicative (liftA2)
+
+newtype Reader r a =
+    Reader { runReader :: r -> a }
+
+myLiftA2 :: Applicative f => (a -> b -> c) -> f a -> f b -> f c
+myLiftA2 f x y = f <$> x <*> y
+
+asks :: (r -> a) -> Reader r a
+asks f = Reader f
+
+instance Functor (Reader r) where
+    fmap f (Reader x) = Reader $ f . x
+
+instance Applicative (Reader r) where
+    pure :: a -> Reader r a
+    pure a = Reader $ \x -> a
+    (<*>) :: Reader r (a -> b) -> Reader r a -> Reader r b
+    (Reader rab) <*> (Reader ra) = Reader $ \r -> rab r (ra r)
+
+instance Monad (Reader r) where
+    return = pure
+    (>>=) :: Reader r a -> (a -> Reader r b) -> Reader r b
+    (Reader ra) >>= aRb = Reader $ \r -> runReader (aRb (ra r)) r
+
+newtype HumanName = HumanName String deriving (Eq, Show)
+newtype DogName = DogName String deriving (Eq, Show)
+newtype Address = Address String deriving (Eq, Show)
+
+data Person = Person { humanName :: HumanName
+                     , dogName :: DogName
+                     , address :: Address
+                     } deriving (Eq, Show)
+
+data Dog = Dog { dogsName :: DogName
+               , dogsAddress :: Address
+               } deriving (Eq, Show)
+
+pers :: Person
+pers = Person (HumanName "Big Bird")
+              (DogName "Barkley")
+              (Address "Sesame Street")
+
+chris :: Person
+chris = Person (HumanName "Chris Allen")
+               (DogName "Papu")
+               (Address "Austin")
+
+getDog :: Person -> Dog
+getDog p = Dog (dogName p) (address p)
+
+getDogR :: Person -> Dog
+getDogR = Dog <$> dogName <*> address
+
+getDogR' :: Person -> Dog
+getDogR' = liftA2 Dog dogName address
+
+getDogRM :: Person -> Dog
+getDogRM = dogName >>= (\x -> address >>= \y -> return $ Dog x y)
diff --git a/Haskell-book/22/ReaderPractice.hs b/Haskell-book/22/ReaderPractice.hs
new file mode 100644
index 0000000..e530d20
--- /dev/null
+++ b/Haskell-book/22/ReaderPractice.hs
@@ -0,0 +1,94 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+module ReaderPractice where
+
+import Control.Applicative
+import Data.Maybe (Maybe(..))
+import Prelude ( zip
+               , foldr
+               , ($)
+               , flip
+               , Integer(..)
+               , (==)
+               , Eq
+               , otherwise
+               , undefined
+               , (+)
+               , Num
+               , (<)
+               , (>)
+               , (&&)
+               , Bool(..)
+               , print
+               , sequenceA
+               , IO(..)
+               , fmap
+               , even
+               , Integral )
+
+x = [1, 2, 3]
+y = [4, 5, 6]
+z = [7, 8, 9]
+
+lookup :: Eq a => a -> [(a, b)] -> Maybe b
+lookup v l = foldr f Nothing l
+    where f _ (Just x) = Just x
+          f (x, y) Nothing
+            | x == v = Just y
+            | otherwise = Nothing
+
+-- zip x and y using 3 as the lookup key
+xs :: Maybe Integer
+xs = lookup 3 (zip x y)
+
+-- zip y and z using 6 as the lookup key
+ys :: Maybe Integer
+ys = lookup 6 (zip y z)
+
+-- zip x and y using 4 as the lookup key
+zs :: Maybe Integer
+zs = lookup 4 $ zip x y
+
+z' :: Integer -> Maybe Integer
+z' = flip lookup $ zip x z
+
+x1 :: Maybe (Integer, Integer)
+x1 = Just (,) <*> xs <*> ys
+
+x2 :: Maybe (Integer, Integer)
+x2 = Just (,) <*> ys <*> zs
+
+x3 :: Integer -> (Maybe Integer, Maybe Integer)
+x3 n = (z' n, z' n)
+
+uncurry :: (a -> b -> c) -> (a, b) -> c
+uncurry f (x, y) = f x y
+
+summed :: Num c => (c, c) -> c
+summed = uncurry (+)
+
+bolt :: Integer -> Bool
+bolt = (&&) <$> (> 3) <*> (< 8)
+
+fromMaybe :: a -> Maybe a -> a
+fromMaybe x (Just y) = y
+fromMaybe x Nothing = x
+
+sequA :: Integral a => a -> [Bool]
+sequA m = sequenceA [(>3), (<8), even] m
+
+s' :: Maybe Integer
+s' = summed <$> ((,) <$> xs <*> ys)
+
+main :: IO ()
+main = do
+    print $ sequenceA [Just 3, Just 2, Just 1]
+    print $ sequenceA [x, y]
+    print $ sequenceA [xs, ys]
+    print $ summed <$> ((,) <$> xs <*> ys)
+    print $ fmap summed ((,) <$> xs <*> zs)
+    print $ bolt 7
+    print $ fmap bolt z
+    print $ sequenceA [(> 3), (< 8), even] 7
+    print $ foldr (&&) True $ sequA $ fromMaybe 0 s'
+    print $ sequA $ fromMaybe 0 s'
+    print $ bolt $ fromMaybe 0 s'
diff --git a/Haskell-book/22/WarmingUp.hs b/Haskell-book/22/WarmingUp.hs
new file mode 100644
index 0000000..b8dd194
--- /dev/null
+++ b/Haskell-book/22/WarmingUp.hs
@@ -0,0 +1,21 @@
+module WarmingUp where
+
+import Data.Char
+
+cap :: [Char] -> [Char]
+cap xs = map toUpper xs
+
+rev :: [Char] -> [Char]
+rev xs = reverse xs
+
+composed :: [Char] -> [Char]
+composed = cap . rev
+
+fmapped :: [Char] -> [Char]
+fmapped = fmap cap rev
+
+tupled :: [Char] -> ([Char], [Char])
+tupled = (,) <$> composed <*> fmapped
+
+tupled' :: [Char] -> ([Char], [Char])
+tupled' = composed >>= (\x -> fmapped >>= (\y -> return (x, y)))
diff --git a/Haskell-book/23/FizzBuzz.hs b/Haskell-book/23/FizzBuzz.hs
new file mode 100644
index 0000000..daee3f7
--- /dev/null
+++ b/Haskell-book/23/FizzBuzz.hs
@@ -0,0 +1,29 @@
+module FizzBuzz where
+
+import Control.Monad
+import Control.Monad.Trans.State
+
+fizzBuzz :: Integer -> String
+fizzBuzz n
+  | n `mod` 15 == 0 = "FizzBuzz"
+  | n `mod` 5 == 0 = "Buzz"
+  | n `mod` 3 == 0 = "Fizz"
+  | otherwise = show n
+
+fizzbuzzList :: [Integer] -> [String]
+fizzbuzzList list = execState (mapM_ addResult list) []
+
+addResult :: Integer -> State [String] ()
+addResult n = do
+    xs <- get
+    let result = fizzBuzz n
+    put (result : xs)
+
+fizzbuzzFromTo :: Integer -> Integer -> [String]
+fizzbuzzFromTo from to = execState (mapM_ addResult (genList from [])) []
+    where genList from soFar
+            | from > to = soFar
+            | otherwise = genList (from + 1) (from : soFar)
+
+main :: IO ()
+main = mapM_ putStrLn $ fizzbuzzFromTo 1 100
diff --git a/Haskell-book/23/Moi.hs b/Haskell-book/23/Moi.hs
new file mode 100644
index 0000000..70352f3
--- /dev/null
+++ b/Haskell-book/23/Moi.hs
@@ -0,0 +1,34 @@
+module Moi where
+
+newtype Moi s a = Moi { runMoi :: s -> (a, s) }
+
+instance Functor (Moi s) where
+    -- fmap :: (a -> b) -> Moi s a -> Moi s b
+    fmap f (Moi g) = Moi (\x -> h $ g x)
+        where h (a, b) = (f a, b)
+
+instance Applicative (Moi s) where
+    -- pure :: a -> Moi s a
+    pure a = Moi (\s -> (a, s))
+    -- (<*>) :: Moi s (a -> b) -> Moi s a -> Moi s b
+    (Moi f) <*> (Moi g) = Moi (\s -> ((fst (f s)) (fst (g s)), s))
+
+instance Monad (Moi s) where
+    return = pure
+    -- (>>=) :: Moi s a -> (a -> Moi s b) -> Moi s b
+    (Moi f) >>= g = Moi (\s -> (runMoi (g (fst (f s)))) (snd (f s)))
+
+get :: Moi s s
+get = Moi $ \a -> (a, a)
+
+put :: s -> Moi s ()
+put s = Moi $ \_ -> ((), s)
+
+exec :: Moi s a -> s -> s
+exec (Moi sa) s = snd (sa s)
+
+eval :: Moi s a -> s -> a
+eval (Moi sa) s = fst (sa s)
+
+modify :: (s -> s) -> Moi s ()
+modify f = Moi $ \a -> ((), f a)
diff --git a/Haskell-book/23/RandomExample/.gitignore b/Haskell-book/23/RandomExample/.gitignore
new file mode 100644
index 0000000..694b2b1
--- /dev/null
+++ b/Haskell-book/23/RandomExample/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+RandomExample.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/23/RandomExample/LICENSE b/Haskell-book/23/RandomExample/LICENSE
new file mode 100644
index 0000000..e037c72
--- /dev/null
+++ b/Haskell-book/23/RandomExample/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2018
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/23/RandomExample/Setup.hs b/Haskell-book/23/RandomExample/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/23/RandomExample/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/23/RandomExample/app/Main.hs b/Haskell-book/23/RandomExample/app/Main.hs
new file mode 100644
index 0000000..d82a4bd
--- /dev/null
+++ b/Haskell-book/23/RandomExample/app/Main.hs
@@ -0,0 +1,4 @@
+module Main where
+
+main :: IO ()
+main = return ()
diff --git a/Haskell-book/23/RandomExample/package.yaml b/Haskell-book/23/RandomExample/package.yaml
new file mode 100644
index 0000000..9fe2ffe
--- /dev/null
+++ b/Haskell-book/23/RandomExample/package.yaml
@@ -0,0 +1,34 @@
+name:                RandomExample
+version:             0.1.0.0
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugene Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- random
+- transformers
+
+library:
+  source-dirs: src
+
+executables:
+  RandomExample-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - RandomExample
+
+tests:
+  RandomExample-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - RandomExample
diff --git a/Haskell-book/23/RandomExample/src/RandomExample.hs b/Haskell-book/23/RandomExample/src/RandomExample.hs
new file mode 100644
index 0000000..deaa449
--- /dev/null
+++ b/Haskell-book/23/RandomExample/src/RandomExample.hs
@@ -0,0 +1,31 @@
+module RandomExample where
+
+import System.Random
+
+data Die = DieOne
+         | DieTwo
+         | DieThree
+         | DieFour
+         | DieFive
+         | DieSix
+         deriving (Eq, Show)
+
+intToDie :: Int -> Die
+intToDie n =
+    case n of
+      1 -> DieOne
+      2 -> DieTwo
+      3 -> DieThree
+      4 -> DieFour
+      5 -> DieFive
+      6 -> DieSix
+      -- Use 'error' __extermely_ sparingly
+      x -> error $ "intToDie got non 1-6 integer: " ++ show x
+
+rollDieThreeTimes :: (Die, Die, Die)
+rollDieThreeTimes = do
+    let s = mkStdGen 0
+        (d1, s1) = randomR (1, 6) s
+        (d2, s2) = randomR (1, 6) s1
+        (d3, _) = randomR (1, 6) s2
+    (intToDie d1, intToDie d2, intToDie d3)
diff --git a/Haskell-book/23/RandomExample/src/RandomExample2.hs b/Haskell-book/23/RandomExample/src/RandomExample2.hs
new file mode 100644
index 0000000..6fbd821
--- /dev/null
+++ b/Haskell-book/23/RandomExample/src/RandomExample2.hs
@@ -0,0 +1,54 @@
+module RandomExample2 where
+
+import Control.Applicative (liftA3)
+import Control.Monad (replicateM)
+import Control.Monad.Trans.State
+import System.Random
+import RandomExample
+
+rollDie :: State StdGen Die
+rollDie = state $ do
+    (n, s) <- randomR (1, 6)
+    return (intToDie n, s)
+
+rollDie' :: State StdGen Die
+rollDie' = intToDie <$> state (randomR (1, 6))
+
+rollDieThreeTimes' :: State StdGen (Die, Die, Die)
+rollDieThreeTimes' = liftA3 (,,) rollDie rollDie rollDie
+
+infiniteDie :: State StdGen [Die]
+infiniteDie = repeat <$> rollDie
+
+nDie :: Int -> State StdGen [Die]
+nDie n = replicateM n rollDie
+
+rollsToGetTwenty :: StdGen -> Int
+rollsToGetTwenty g = go 0 0 g
+    where
+        go :: Int -> Int -> StdGen -> Int
+        go sum count gen
+          | sum >= 20 = count
+          | otherwise =
+              let (die, nextGen) = randomR (1, 6) gen
+               in go (sum + die) (count + 1) nextGen
+
+rollsToGetN :: Int -> StdGen -> Int
+rollsToGetN limit g = go 0 0 g
+    where
+        go :: Int -> Int -> StdGen -> Int
+        go sum count gen
+          | sum >= limit = count
+          | otherwise =
+              let (die, nextGen) = randomR (1, 6) gen
+               in go (sum + die) (count + 1) nextGen
+
+rollsCountLogged :: Int -> StdGen -> (Int, [Die])
+rollsCountLogged limit g = go 0 0 g []
+    where
+        go :: Int -> Int -> StdGen -> [Die] -> (Int, [Die])
+        go sum count gen dies
+          | sum >= limit = (count, dies)
+          | otherwise =
+              let (die, nextGen) = randomR (1, 6) gen
+               in go (sum + die) (count + 1) nextGen ((intToDie die) : dies)
diff --git a/Haskell-book/23/RandomExample/stack.yaml b/Haskell-book/23/RandomExample/stack.yaml
new file mode 100644
index 0000000..9c6b17c
--- /dev/null
+++ b/Haskell-book/23/RandomExample/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-10.9
+
+# 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/23/RandomExample/test/Spec.hs b/Haskell-book/23/RandomExample/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/Haskell-book/23/RandomExample/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/Haskell-book/24/LearnParsers/.gitignore b/Haskell-book/24/LearnParsers/.gitignore
new file mode 100644
index 0000000..b3162b7
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+LearnParsers.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/24/LearnParsers/ChangeLog.md b/Haskell-book/24/LearnParsers/ChangeLog.md
new file mode 100644
index 0000000..365af37
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/ChangeLog.md
@@ -0,0 +1,3 @@
+# Changelog for LearnParsers
+
+## Unreleased changes
diff --git a/Haskell-book/24/LearnParsers/Setup.hs b/Haskell-book/24/LearnParsers/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/24/LearnParsers/app/Main.hs b/Haskell-book/24/LearnParsers/app/Main.hs
new file mode 100644
index 0000000..57ff0bf
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/app/Main.hs
@@ -0,0 +1,24 @@
+module Main where
+
+import Control.Applicative
+import LearnParsers
+import Text.Fractions
+import Text.Trifecta
+import Text.Parser.Combinators
+
+unitOfSuccess :: (TokenParsing m, Monad m) => m Integer
+unitOfSuccess = do
+    number <- integer
+    _ <- eof
+    return number
+
+type FractionOrNumber = Either Rational Integer
+
+parseFractionOrNumber :: Parser FractionOrNumber
+parseFractionOrNumber =  skipMany (oneOf "\n")
+     >> (Left <$> try virtuousFraction)
+    <|> (Right <$> integer)
+
+main :: IO ()
+main = do
+    print $ parseString unitOfSuccess mempty "123"
diff --git a/Haskell-book/24/LearnParsers/package.yaml b/Haskell-book/24/LearnParsers/package.yaml
new file mode 100644
index 0000000..ef83d5d
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/package.yaml
@@ -0,0 +1,24 @@
+name:                LearnParsers
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- trifecta
+- parsers
+
+library:
+  source-dirs: src
+
+executables:
+  LearnParsers:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - LearnParsers
diff --git a/Haskell-book/24/LearnParsers/src/LearnParsers.hs b/Haskell-book/24/LearnParsers/src/LearnParsers.hs
new file mode 100644
index 0000000..9c349fd
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/src/LearnParsers.hs
@@ -0,0 +1,45 @@
+module LearnParsers where
+
+import Text.Trifecta
+
+stop :: Parser a
+stop = unexpected "stop"
+
+-- read a single character '1'
+one = char '1'
+
+-- read a single character '1', then die
+one' = one >> stop
+-- equivalent to char '1' >> stop
+
+-- read two characters, '1', and '2'
+oneTwo = char '1' >> char '2'
+
+-- read two characters,
+-- '1' and '2', then die
+
+oneTwo' = oneTwo >> stop
+
+testParse :: Parser Char -> IO ()
+testParse p = print $ parseString p mempty "123"
+
+pNL s = putStrLn ('\n' : s)
+
+oneTwoThree :: Parser String
+oneTwoThree = choice
+            [ string "123"
+            , string "12"
+            , string "1"
+            ]
+
+oneTwoThree' = oneTwoThree >> stop
+
+testParse' :: Parser String -> IO ()
+testParse' p = print $ parseString p mempty "123"
+
+oneTwoThree'' :: Parser Char
+oneTwoThree'' = choice
+        [ one
+        , oneTwo
+        , char '1' >> char '2' >> char '3'
+        ]
diff --git a/Haskell-book/24/LearnParsers/src/Text/Fractions.hs b/Haskell-book/24/LearnParsers/src/Text/Fractions.hs
new file mode 100644
index 0000000..f09efc0
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/src/Text/Fractions.hs
@@ -0,0 +1,31 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Text.Fractions where
+
+import Control.Applicative
+import Data.Ratio ((%))
+import Text.Trifecta
+
+badFraction = "1/0"
+
+alsoBad = "10"
+
+shouldWork = "1/2"
+
+shouldAlsoWork = "2/1"
+
+parseFraction :: Parser Rational
+parseFraction = do
+    numerator <- decimal
+    char '/'
+    denominator <- decimal
+    return (numerator % denominator)
+
+virtuousFraction :: Parser Rational
+virtuousFraction = do
+    numerator <- decimal
+    char '/'
+    denominator <- decimal
+    case denominator of
+      0 -> fail "Denominator cannot be zero"
+      _ -> return $ numerator % denominator
diff --git a/Haskell-book/24/LearnParsers/stack.yaml b/Haskell-book/24/LearnParsers/stack.yaml
new file mode 100644
index 0000000..c741be6
--- /dev/null
+++ b/Haskell-book/24/LearnParsers/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-11.0
+
+# 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/24/ParserExercises/.gitignore b/Haskell-book/24/ParserExercises/.gitignore
new file mode 100644
index 0000000..1918f96
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+ParserExercises.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/24/ParserExercises/Setup.hs b/Haskell-book/24/ParserExercises/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/24/ParserExercises/package.yaml b/Haskell-book/24/ParserExercises/package.yaml
new file mode 100644
index 0000000..8740046
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/package.yaml
@@ -0,0 +1,38 @@
+name:                ParserExercises
+version:             0.1.0.0
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- parsec
+- trifecta
+- QuickCheck
+- time
+- containers
+
+library:
+  source-dirs: src
+
+tests:
+  ParserExercises-test:
+    main:                Main.hs
+    source-dirs:         test/Spec
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - ParserExercises
+    - hspec
+
+  Log-test:
+    main:                Main.hs
+    source-dirs:         test/LogTest
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - ParserExercises
diff --git a/Haskell-book/24/ParserExercises/src/Base10Integer.hs b/Haskell-book/24/ParserExercises/src/Base10Integer.hs
new file mode 100644
index 0000000..4e8ee3a
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/src/Base10Integer.hs
@@ -0,0 +1,52 @@
+module Base10Integer where
+
+import Control.Applicative
+import Text.Trifecta
+
+-- 2. Write a parser for positive integer values. Don't reuse the preexisting
+-- digit or integer functions, but you can use the rest of the libraries we've
+-- shown you so far. You are not expected to write a parsing library from
+-- scratch.
+--
+-- Hint: Assume you're parsing base-10 numbers. Use arithmetic as a cheap
+-- "accumulator" for your final number as you parse each digit left-to-right.
+
+parseDigit :: Parser Char
+parseDigit = (char '0')
+    <|> (char '1')
+    <|> (char '2')
+    <|> (char '3')
+    <|> (char '4')
+    <|> (char '5')
+    <|> (char '6')
+    <|> (char '7')
+    <|> (char '8')
+    <|> (char '9')
+
+charToDigit :: Char -> Integer
+charToDigit c = case c of
+                    '0' -> 0
+                    '1' -> 1
+                    '2' -> 2
+                    '3' -> 3
+                    '4' -> 4
+                    '5' -> 5
+                    '6' -> 6
+                    '7' -> 7
+                    '8' -> 8
+                    '9' -> 9
+
+base10Integer :: Parser Integer
+base10Integer = do
+    number <- some parseDigit
+    let n = foldl (\acc x -> (acc * 10) + (charToDigit x)) 0 number
+    return n
+
+-- 3. Extend the parser your wrote to handle negative and positive integers.
+-- Try writing a new parser in terms of the one you already have to do this.
+base10Integer' :: Parser Integer
+base10Integer' = do
+    negative <- (char '-' >> (return negate)) <|> (return id)
+    number <- some parseDigit
+    let n = foldl (\acc x -> (acc * 10) + (charToDigit x)) 0 number
+    return $ negative n
diff --git a/Haskell-book/24/ParserExercises/src/IPAddress.hs b/Haskell-book/24/ParserExercises/src/IPAddress.hs
new file mode 100644
index 0000000..e6a7102
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/src/IPAddress.hs
@@ -0,0 +1,260 @@
+module IPAddress where
+
+import Numeric
+import Control.Monad (join)
+import Control.Applicative
+import Data.Char
+import Data.List
+import Data.Maybe
+import Data.Map (lookup, Map(..), fromList)
+import Data.Word
+import Data.Bits
+import Text.Trifecta
+
+-- 6. Write a parser for IPv4 addresses.
+
+data IPAddress = IPAddress Word32 deriving (Eq, Ord)
+
+parseIP4 :: Parser IPAddress
+parseIP4 = do
+    p1 <- natural
+    _ <- char '.'
+    p2 <- natural
+    _ <- char '.'
+    p3 <- natural
+    _ <- char '.'
+    p4 <- natural
+    return $ IPAddress $ fromIntegral $ xor (xor (xor (shift p1 24) (shift p2 16)) (shift p3 8)) p4
+
+-- A 32-bit word is a 32-bit unsigned int. Lowest value is 0 rahter than being
+-- capable of representing negative numbers, but the highest possible value in
+-- the same number of bits is twice as high.
+--
+-- Word32 is an appropriate and compact way to represent IPv4 addresses. You
+-- are expected to figure out not only how to parse the typical IP address
+-- format, but how IP addresses work numerically insofar as is required to
+-- write a working parser. This will require using a search engine unless you
+-- have an appropriate book on internet networking handy.
+
+-- 7. Same as before, but IPv6.
+
+data IPAddress6 = IPAddress6 Word64 Word64 deriving (Eq, Ord)
+
+-- One of the trickier parts about IPv6 will be full vs. collapsed
+-- addresses and the abbrevations. See this Q&A thread 13 about
+-- IPv6 abbreviations for more.
+
+
+newtype IPV6Normed = IPV6Normed String
+  deriving (Eq, Ord, Show)
+
+newtype IPV6Str = IPV6Str String
+  deriving (Eq, Ord, Show)
+
+spanList :: ([a] -> Bool) -> [a] -> ([a], [a])
+spanList _ [] = ([],[])
+spanList func list@(x:xs) =
+    if func list
+       then (x:ys,zs)
+       else ([],list)
+    where (ys,zs) = spanList func xs
+
+breakList :: ([a] -> Bool) -> [a] -> ([a], [a])
+breakList func = spanList (not . func)
+
+split' :: Eq a => [a] -> [a] -> [[a]]
+split' _ [] = []
+split' delim str =
+    let (firstline, remainder) = breakList (isPrefixOf delim) str
+        in 
+        firstline : case remainder of
+                                   [] -> []
+                                   x -> if x == delim
+                                        then [] : []
+                                        else split' delim 
+                                                 (drop (length delim) x)
+
+join :: [a] -> [[a]] -> [a]
+join delim l = concat (intersperse delim l)
+
+replace :: Eq a => [a] -> [a] -> [a] -> [a]
+replace old new l = IPAddress.join new . split' old $ l
+
+split :: Eq a => a -> [a] -> [[a]]
+split d [] = []
+split d s = x : split d (drop 1 y)
+  where
+    (x, y) = Data.List.span (/= d) s
+
+twoRaised16Exp :: [Integer]
+twoRaised16Exp = fmap ((2 ^ 16) ^) [0,1 ..]
+
+validHexChars :: String
+validHexChars = "0123456789abcdefABCDEF"
+
+validHexCharsLowerOnly :: String
+validHexCharsLowerOnly = "0123456789abcdef"
+
+buildExpanded0s :: Int -> String
+buildExpanded0s i = intersperse ':' (take i (repeat '0'))
+
+ipv6NormedToIPAddress6 :: IPV6Normed -> IPAddress6
+ipv6NormedToIPAddress6 (IPV6Normed str) = IPAddress6 quotient remainder
+  where
+    asSegs = split ':' str
+    zippedWithExp = zip (reverse asSegs) twoRaised16Exp
+    asInteger = foldr (\(s, exp) acc -> hexToDec s * exp + acc) 0 zippedWithExp
+    (q, r) = quotRem asInteger word64Max
+    quotient = fromIntegral q
+    remainder = fromIntegral r
+
+hexToDec :: String -> Integer
+hexToDec s = toInteger asInt
+  where
+    asInt = baseNToDec 16 (\c -> fromMaybe 0 (Data.Map.lookup (toLower c) hexCharToValue)) s
+
+baseNToDec :: Num i => i -> (a -> i) -> [a] -> i
+baseNToDec base toInt = foldl' (\acc n -> base * acc + toInt n ) 0
+
+hexCharToValue :: Map Char Int
+hexCharToValue = Data.Map.fromList $ zip validHexCharsLowerOnly [0 ..]
+
+word64Max :: Integer
+word64Max = toInteger (maxBound :: Word64)
+
+mkIPV6Normed :: String -> Either String IPV6Normed
+mkIPV6Normed origS = result
+  where
+    expand s
+      | s == "::" = IPV6Normed $ buildExpanded0s 8
+      | isPrefixOf "::" s =
+          let expandCnt = 8 - (length $ split ':' s) + 2
+              filler = buildExpanded0s expandCnt ++ ":"
+              replaced = replace "::" filler s
+          in IPV6Normed replaced
+      | isSuffixOf "::" s =
+          let expandCnt = 8 - (length $ split ':' s) + 1
+              filler = ':' : buildExpanded0s expandCnt
+              replaced = replace "::" filler s
+          in IPV6Normed replaced
+      | isInfixOf "::" s =
+          let expandCnt = 8 - (length $ split ':' s) + 1
+              filler = ':' : buildExpanded0s expandCnt ++ ":"
+              replaced = replace "::" filler s
+          in IPV6Normed replaced
+      | otherwise = IPV6Normed s
+    expanded = expand origS
+    IPV6Normed expandedStr = expanded
+    result = if length (split ':' expandedStr) == 8
+               then Right expanded
+               else Left "invalid sections"
+
+parseIPV6Section :: Parser String
+parseIPV6Section = do
+  mL <- optional (try $ string "::" <|> string ":")
+  seq <- some (oneOf validHexChars)
+  mR <- optional (try $ string "::" <|> string ":")
+  let lowered = map toLower seq
+      l = fromMaybe "" mL
+      r = fromMaybe "" mR
+  return $ l ++ lowered ++ r
+
+parseIPV6Str :: Parser IPV6Str
+parseIPV6Str = do
+  s <- (try $ (fmap (: []) (string "::" <* eof))) <|> manyTill parseIPV6Section
+                                                        eof
+  if length s < 1
+    then fail "Did not find valid sections"
+    else return $ IPV6Str $ Control.Monad.join s
+
+parseIPV6Normed :: Parser IPV6Normed
+parseIPV6Normed = do
+  str <- parseIPV6Str
+  let IPV6Str (s) = str
+      full = mkIPV6Normed s
+  case full of
+    Left err      -> fail err
+    Right fullstr -> return fullstr
+
+parseIP6 :: Parser IPAddress6
+parseIP6 = do
+    normed <- parseIPV6Normed
+    return $ ipv6NormedToIPAddress6 normed
+
+-- 8. Remove the derived Show instances from the IPAddress/IPAddress6
+-- types, and write your own Show instance for each type that renders in the
+-- typical textual format appropriate to each.
+
+ipAddressToIPV4DotFields :: IPAddress -> [Integer]
+ipAddressToIPV4DotFields (IPAddress word) = repr
+  where
+    asInteger = toInteger word
+    repr = decToBaseN asInteger 0 [0 .. 255]
+
+instance Show IPAddress where
+  show ip = Control.Monad.join $ intersperse "." asStrings
+    where
+      repr = ipAddressToIPV4DotFields ip
+      asStrings = fmap show repr
+
+ipAddress6toInteger :: IPAddress6 -> Integer
+ipAddress6toInteger (IPAddress6 q r) = toInteger q * word64Max + toInteger r
+
+iPAddress6ToIPV6Normed :: IPAddress6 -> IPV6Normed
+iPAddress6ToIPV6Normed ip = IPV6Normed s
+  where
+    asInteger = ipAddress6toInteger ip
+    chopped = integerToChoppedUp asInteger
+    ss = fmap integerToHexString chopped
+    fillCnt = 8 - length ss
+    filled = (take fillCnt (repeat "0")) ++ ss
+    s = Control.Monad.join $ intersperse ":" filled
+
+instance Show IPAddress6 where
+  show ip = normed
+    where IPV6Normed normed = iPAddress6ToIPV6Normed ip
+
+-- 9. Write a function that converts between IPAddress and IPAddress6.
+
+decToBaseN :: Integral a => a -> b -> [b] -> [b]
+decToBaseN i zero digits = if base == 0
+                                  then []
+                                  else go i []
+  where
+    base = fromIntegral $ length digits
+    go 0 [] = [zero]
+    go 0 acc = acc
+    go curr acc =
+      let (q, r) = quotRem curr base
+      in go q ((digits !! fromIntegral r) : acc)
+
+integerToHexString :: Integer -> String
+integerToHexString i = decToBaseN i '0' validHexCharsLowerOnly
+
+integerToChoppedUp :: Integer -> [Integer]
+integerToChoppedUp i = go i []
+  where
+    go 0 [] = [0]
+    go 0 acc = acc
+    go curr acc =
+      let (q, r) = quotRem curr (2 ^ 16)
+       in go q (r : acc)
+
+ipV4ToIpV6Normed :: IPAddress -> IPV6Normed
+ipV4ToIpV6Normed (IPAddress word) = normed
+  where
+    asInteger = toInteger word
+    chopped = integerToChoppedUp asInteger
+    ss = fmap integerToHexString chopped
+    fillCnt = 8 - length ss - 1
+    -- - ffff signifies an ip4 to ip6 conversion
+    -- (http://www.tcpipguide.com/free/t_IPv6IPv4AddressEmbedding-2.htm)
+    filled = (take fillCnt $ repeat "0") ++ ["ffff"] ++ ss
+    s = Control.Monad.join $ intersperse ":" filled
+    normed = IPV6Normed s
+
+ipV4ToIpV6 :: IPAddress -> IPAddress6
+ipV4ToIpV6 ip = ipv6
+  where
+    normed = ipV4ToIpV6Normed ip
+    ipv6 = ipv6NormedToIPAddress6 normed
diff --git a/Haskell-book/24/ParserExercises/src/LogParser.hs b/Haskell-book/24/ParserExercises/src/LogParser.hs
new file mode 100644
index 0000000..480498d
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/src/LogParser.hs
@@ -0,0 +1,83 @@
+module LogParser where
+
+import Control.Applicative
+import Data.Time
+import Test.QuickCheck
+import Text.Trifecta
+
+-- 5. Write a parser for a log file format and sum the time spent in
+-- each activity. Additionally, provide an alternative aggregation
+-- of the data that provides average time spent per activity per day.
+-- The format supports the use of comments which your parser
+-- will have to ignore. The # characters followed by a date mark
+-- the beginning of a particular day.
+--
+-- You are to derive a reasonable datatype for representing this
+-- data yourself. For bonus points, make this bi-directional by
+-- making a Show representation for the datatype which matches
+-- the format you are parsing. Then write a generator for this data
+-- using QuickCheck’s Gen and see if you can break your parser
+-- with QuickCheck.
+
+data Statement = Statement TimeOfDay String deriving Eq
+data LogEntry = LogEntry Day [Statement] deriving Eq
+newtype Log = Log { getLog :: [LogEntry] }
+
+instance Show Statement where
+    show (Statement x y) = (formatTime defaultTimeLocale "%R" x) ++ " " ++ y
+
+instance Show LogEntry where
+    show (LogEntry x y) = "# " ++ (show x) ++ "\n"
+                      ++ (foldl (\acc v -> acc ++ (show v) ++ "\n") "" y)
+
+instance Show Log where
+    show (Log y) = (foldl (\acc v -> acc ++ (show v) ++ "\n") "" y)
+
+instance Arbitrary Statement where
+    arbitrary = do
+        h <- choose (0, 23)
+        m <- choose (0, 59)
+        text <- listOf1 $ elements ['.'..'~']
+        return $ Statement (TimeOfDay h m 0) text
+
+instance Arbitrary LogEntry where
+    arbitrary = do
+        day <- arbitrary
+        statements <- arbitrary
+        return $ LogEntry (ModifiedJulianDay day) statements
+
+skipEOL :: Parser ()
+skipEOL = skipMany (oneOf "\n")
+
+skipComments :: Parser ()
+skipComments =
+    skipMany (do _ <- char '-'
+                 _ <- char '-'
+                 skipMany (noneOf "\n")
+                 skipEOL)
+
+parseStatement :: Parser Statement
+parseStatement = do
+    h <- integer
+    _ <- char ':'
+    m <- integer
+    text <- manyTill anyChar (try (string "--") <|> (string "\n") <|> (eof >> return ""))
+    skipComments
+    skipEOL
+    return $ Statement (TimeOfDay (fromIntegral h) (fromIntegral m) 0) text
+
+parseLogEntry :: Parser LogEntry
+parseLogEntry = do
+    _ <- string "# "
+    y <- integer
+    _ <- char '-'
+    m <- integer
+    _ <- char '-'
+    d <- integer
+    skipComments
+    skipEOL
+    statements <- many parseStatement
+    return $ LogEntry (fromGregorian (fromIntegral y) (fromIntegral m) (fromIntegral d)) statements
+
+parseLog :: Parser Log
+parseLog = Log <$> many parseLogEntry
diff --git a/Haskell-book/24/ParserExercises/src/PhoneNumber.hs b/Haskell-book/24/ParserExercises/src/PhoneNumber.hs
new file mode 100644
index 0000000..dad75a7
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/src/PhoneNumber.hs
@@ -0,0 +1,28 @@
+module PhoneNumber where
+
+import Control.Applicative
+import Text.Trifecta
+
+-- 4. Write a parser for US/Canada phone numbers with varying formats.
+-- Cf. Wikipeida's article on "National conventions for writing telephone
+-- numbers". You are encouraged to adapt the exercise to your locality's
+-- conventions if they are not part of the NNAP scheme.
+
+-- aka area code
+type NumberingPlanArea = Int
+type Exchange = Int
+type LineNumber = Int
+
+data PhoneNumber = PhoneNumber NumberingPlanArea Exchange LineNumber
+    deriving (Eq, Show)
+
+parsePhone :: Parser PhoneNumber
+parsePhone = do
+    _ <- optional ((try $ char '(') <|> (try (char '1' >> char '-')))
+    area <- count 3 digit
+    _ <- optional $ (try $ char ')')
+    _ <- optional $  (try $ char ' ') <|> (try $ char '-')
+    exchange <- count 3 digit
+    _ <- optional $ (char ' ') <|> (char '-')
+    lineNumber <- decimal
+    return $ PhoneNumber (read area) (read exchange) (fromIntegral lineNumber)
diff --git a/Haskell-book/24/ParserExercises/src/SemVer.hs b/Haskell-book/24/ParserExercises/src/SemVer.hs
new file mode 100644
index 0000000..47b49ab
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/src/SemVer.hs
@@ -0,0 +1,51 @@
+module SemVer where
+
+import Control.Applicative
+import Text.Trifecta
+
+-- 1. Write a parser for semantic versions as defined by http://semver.org/.
+-- After making a working parser, write an Ord instance for the SemVer type
+-- that obeys the specification outlined on the SemVer website.
+
+-- Relevant to precedence/ordering,
+-- cannot sort numbers like strings.
+data NumberOrString = NOSS String
+                    | NOSI Integer
+                    deriving (Eq, Show)
+
+type Major = Integer
+type Minor = Integer
+type Patch = Integer
+type Release = [NumberOrString]
+type Metadata = [NumberOrString]
+
+data SemVer = SemVer Major Minor Patch Release Metadata
+    deriving (Eq, Show)
+
+parseNos :: Parser NumberOrString
+parseNos = do
+    nos <- (NOSI <$> integer)
+       <|> (NOSS <$> some letter)
+    return nos
+
+parseRelease :: Parser [NumberOrString]
+parseRelease = do
+    _ <- char '-'
+    sepBy parseNos (char '.')
+
+parseMetadata :: Parser [NumberOrString]
+parseMetadata = do
+    _ <- char '+'
+    sepBy parseNos (char '.')
+
+parseSemVer :: Parser SemVer
+parseSemVer = do
+    major <- decimal
+    _ <- char '.'
+    minor <- decimal
+    _ <- char '.'
+    patch <- decimal
+    release <- option [] parseRelease
+    metadata <- option [] parseMetadata
+
+    return $ SemVer major minor patch release metadata
diff --git a/Haskell-book/24/ParserExercises/stack.yaml b/Haskell-book/24/ParserExercises/stack.yaml
new file mode 100644
index 0000000..e60ca15
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/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-11.1
+
+# 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/24/ParserExercises/test/LogTest/Main.hs b/Haskell-book/24/ParserExercises/test/LogTest/Main.hs
new file mode 100644
index 0000000..7d1d135
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/test/LogTest/Main.hs
@@ -0,0 +1,14 @@
+module Main where
+
+import LogParser
+import Test.QuickCheck
+import Text.Trifecta
+
+maybeSuccess :: Text.Trifecta.Result a -> Maybe a
+maybeSuccess (Text.Trifecta.Success a) = Just a
+maybeSuccess _ = Nothing
+
+main :: IO ()
+main = do
+    quickCheck ((\s -> (maybeSuccess $ parseString parseStatement mempty (show s)) == (Just s)) :: Statement -> Bool)
+    quickCheck ((\s -> (maybeSuccess $ parseString parseLogEntry mempty (show s)) == (Just s)) :: LogEntry -> Bool)
diff --git a/Haskell-book/24/ParserExercises/test/Spec/Main.hs b/Haskell-book/24/ParserExercises/test/Spec/Main.hs
new file mode 100644
index 0000000..23781c6
--- /dev/null
+++ b/Haskell-book/24/ParserExercises/test/Spec/Main.hs
@@ -0,0 +1,107 @@
+import SemVer
+import Base10Integer
+import PhoneNumber
+import IPAddress
+import Test.Hspec
+import Text.Trifecta
+
+maybeSuccess :: Result a -> Maybe a
+maybeSuccess (Success a) = Just a
+maybeSuccess _ = Nothing
+
+parseIP :: String -> Maybe IPAddress
+parseIP s = o
+    where r = parseString parseIP4 mempty s
+          o = case r of
+                (Success o) -> Just o
+                _           -> Nothing
+
+parseIP6' :: String -> Maybe IPAddress6
+parseIP6' s = o
+    where r = parseString parseIP6 mempty s
+          o = case r of
+                (Success o) -> Just o
+                _           -> Nothing
+
+main :: IO ()
+main = hspec $ do
+    describe "parseSemVer" $ do
+        it "parses minimum SemVer" $ do
+            let got = maybeSuccess $ parseString parseSemVer mempty "2.1.1"
+             in got `shouldBe` Just (SemVer 2 1 1 [] [])
+        it "parses release field" $ do
+            let got = maybeSuccess $ parseString parseSemVer mempty "1.0.0-x.7.z.92"
+                expected = Just $ SemVer 1 0 0 [NOSS "x", NOSI 7, NOSS "z", NOSI 92] []
+             in got `shouldBe` expected
+
+    describe "parseDigit" $ do
+        it "parses the first digit of '123'" $ do
+            let got = maybeSuccess $ parseString parseDigit mempty "123"
+                expected = Just '1'
+             in got `shouldBe` expected
+        it "fails on 'abc'" $ do
+            let got = maybeSuccess $ parseString parseDigit mempty "abc"
+                expected = Nothing
+             in got `shouldBe` expected
+
+    describe "base10Integer" $ do
+        it "parses the integer in '123abc'" $ do
+            let got = maybeSuccess $ parseString base10Integer mempty "123abc"
+                expected = Just 123
+             in got `shouldBe` expected
+        it "fails on 'abc'" $ do
+            let got = maybeSuccess $ parseString base10Integer mempty "abc"
+                expected = Nothing
+             in got `shouldBe` expected
+
+    describe "base10Integer'" $ do
+        it "parses negative numbers" $ do
+            let got = maybeSuccess $ parseString base10Integer' mempty "-123abc"
+                expected = Just (-123)
+             in got `shouldBe` expected
+
+    describe "parsePhone" $ do
+        it "parses '123-456-7890'" $ do
+            let actual = maybeSuccess $ parseString parsePhone mempty "123-456-7890"
+                expected = Just $ PhoneNumber 123 456 7890
+             in actual `shouldBe` expected
+        it "parses '1234567890'" $ do
+            let actual = maybeSuccess $ parseString parsePhone mempty "1234567890"
+                expected = Just $ PhoneNumber 123 456 7890
+             in actual `shouldBe` expected
+        it "parses '(123) 456-7890'" $ do
+            let actual = maybeSuccess $ parseString parsePhone mempty "(123) 456-7890"
+                expected = Just $ PhoneNumber 123 456 7890
+             in actual `shouldBe` expected
+        it "parses '1-123-456-7890'" $ do
+            let actual = maybeSuccess $ parseString parsePhone mempty "1-123-456-7890"
+                expected = Just $ PhoneNumber 123 456 7890
+             in actual `shouldBe` expected
+
+    describe "parseIP4" $ do
+        it "parses localhost" $ do
+            let actual = maybeSuccess $ parseString parseIP4 mempty "127.0.0.1"
+                expected = Just $ IPAddress 2130706433
+             in actual `shouldBe` expected
+
+    describe "parseIP6" $ do
+        it "parses localhost" $ do
+            let actual = maybeSuccess $ parseString parseIP6 mempty "::1"
+                expected = Just $ IPAddress6 0 1
+             in actual `shouldBe` expected
+
+    describe "ipV4ToIpV6" $
+        it "should work" $ do
+            (show . ipV4ToIpV6 <$> parseIP "124.155.107.12") `shouldBe` Just "0:0:0:0:0:ffff:7c9b:6b0c"
+            (show . ipV4ToIpV6 <$> parseIP "192.168.0.1") `shouldBe` Just "0:0:0:0:0:ffff:c0a8:1"
+
+    describe "show" $ do
+        it "should show IPAddress6 properly" $ do
+            (show <$> parseIP6' "ff39:0:0:0:2f2:b3ff:f23d:8d5") `shouldBe` Just "ff39:0:0:0:2f2:b3ff:f23d:8d5"
+            (show <$> parseIP6' "9ff3:EA8::8A:30:2F0C:1F7A") `shouldBe` Just "9ff3:ea8:0:0:8a:30:2f0c:1f7a"
+            (show <$> parseIP6' "::ffff:abc:fed9") `shouldBe` Just "0:0:0:0:0:ffff:abc:fed9"
+
+        it "should show IPAddress properly" $ do
+            (show <$> parseIP "152.163.254.3") `shouldBe` Just "152.163.254.3"
+            (show <$> parseIP "224.165.197.142") `shouldBe` Just "224.165.197.142"
+            (show <$> parseIP "124.155.107.12") `shouldBe` Just "124.155.107.12"
diff --git a/Haskell-book/24/language-dot/LICENSE b/Haskell-book/24/language-dot/LICENSE
new file mode 100644
index 0000000..59fd4e9
--- /dev/null
+++ b/Haskell-book/24/language-dot/LICENSE
@@ -0,0 +1,29 @@
+Copyright (c) 2009, Galois, Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+
+  * Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+  * Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in
+    the documentation and/or other materials provided with the
+    distribution.
+  * Neither the name of the Galois, Inc. nor the names of its
+    contributors may be used to endorse or promote products derived
+    from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/24/language-dot/Setup.hs b/Haskell-book/24/language-dot/Setup.hs
new file mode 100644
index 0000000..dba3cdf
--- /dev/null
+++ b/Haskell-book/24/language-dot/Setup.hs
@@ -0,0 +1,12 @@
+module Main where
+
+import Distribution.Simple (defaultMainWithHooks, simpleUserHooks, runTests)
+import System.Process      (system)
+
+main :: IO ()
+main =
+    defaultMainWithHooks $ simpleUserHooks { runTests = runTests' }
+  where
+    runTests' _ _ _ _ = do
+        system "runhaskell -DTEST -i./src src/test.hs"
+        return ()
diff --git a/Haskell-book/24/language-dot/language-dot.cabal b/Haskell-book/24/language-dot/language-dot.cabal
new file mode 100644
index 0000000..5463485
--- /dev/null
+++ b/Haskell-book/24/language-dot/language-dot.cabal
@@ -0,0 +1,59 @@
+name:         language-dot
+version:      0.0.8
+category:     Language
+synopsis:     A library for the analysis and creation of Graphviz DOT files
+description:  A library for the analysis and creation of Graphviz DOT files.
+author:       Brian Lewis <brian@lorf.org>
+maintainer:   Brian Lewis <brian@lorf.org>
+copyright:    (c) 2009 Galois, Inc.
+license:      BSD3
+license-file: LICENSE
+
+cabal-version: >= 1.6
+build-type:    Custom
+
+extra-source-files:
+  src/test.hs
+
+flag executable
+  description: Build the `ppdot' executable.
+  default:     True
+
+library
+  hs-source-dirs:
+    src
+
+  exposed-modules:
+    Language.Dot
+    Language.Dot.Parser
+    Language.Dot.Pretty
+    Language.Dot.Syntax
+
+  build-depends:
+    base    == 4.*,
+    mtl     == 1.* || == 2.*,
+    parsec  == 3.*,
+    pretty  == 1.*
+
+  ghc-options: -Wall
+  if impl(ghc >= 6.8)
+    ghc-options: -fwarn-tabs
+
+executable ppdot
+  if flag(executable)
+    buildable: True
+  else
+    buildable: False
+
+  hs-source-dirs:
+    src
+
+  main-is: ppdot.hs
+
+  ghc-options: -Wall
+  if impl(ghc >= 6.8)
+    ghc-options: -fwarn-tabs
+
+source-repository head
+  type:     git
+  location: git://github.com/bsl/language-dot.git
diff --git a/Haskell-book/24/language-dot/src/Language/Dot.hs b/Haskell-book/24/language-dot/src/Language/Dot.hs
new file mode 100644
index 0000000..b1a87a3
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/Language/Dot.hs
@@ -0,0 +1,10 @@
+module Language.Dot
+  ( module Language.Dot.Parser
+  , module Language.Dot.Pretty
+  , module Language.Dot.Syntax
+  )
+  where
+
+import Language.Dot.Parser
+import Language.Dot.Pretty
+import Language.Dot.Syntax
diff --git a/Haskell-book/24/language-dot/src/Language/Dot/Parser.hs b/Haskell-book/24/language-dot/src/Language/Dot/Parser.hs
new file mode 100644
index 0000000..a13d457
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/Language/Dot/Parser.hs
@@ -0,0 +1,486 @@
+{-# LANGUAGE CPP #-}
+
+module Language.Dot.Parser
+  ( parseDot
+#ifdef TEST
+  , parsePort
+  , parseCompass
+  , parseAttribute
+  , parseId
+#endif
+  )
+  where
+
+import Control.Applicative ((<$>), (<*>), (<*), (*>))
+import Control.Monad       (when)
+import Data.Char           (digitToInt, toLower)
+import Data.List           (foldl')
+import Data.Maybe          (fromJust, fromMaybe, isJust)
+import Numeric             (readFloat)
+
+import Text.Parsec
+import Text.Parsec.Language
+import Text.Parsec.String
+import Text.Parsec.Token
+
+import Language.Dot.Syntax
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseDot
+  :: String  -- ^ origin of the data, e.g., the name of a file
+  -> String  -- ^ DOT source code
+  -> Either ParseError Graph
+parseDot origin =
+    parse (whiteSpace' >> parseGraph) origin . preprocess
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+preprocess :: String -> String
+preprocess =
+    unlines . map commentPoundLines . lines
+  where
+    commentPoundLines []         = []
+    commentPoundLines line@(c:_) = if c == '#' then "// " ++ line else line
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseGraph :: Parser Graph
+parseGraph =
+    ( Graph <$>
+          parseGraphStrictness
+      <*> parseGraphDirectedness
+      <*> optionMaybe parseId
+      <*> parseStatementList
+    )
+    <?> "graph"
+
+parseGraphStrictness :: Parser GraphStrictness
+parseGraphStrictness =
+    ((reserved' "strict" >> return StrictGraph) <|> return UnstrictGraph)
+    <?> "graph strictness"
+
+parseGraphDirectedness :: Parser GraphDirectedness
+parseGraphDirectedness =
+    (   (reserved' "graph"   >> return UndirectedGraph)
+    <|> (reserved' "digraph" >> return DirectedGraph)
+    )
+    <?> "graph directedness"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseStatementList :: Parser [Statement]
+parseStatementList =
+    braces' (parseStatement `endBy` optional semi')
+    <?> "statement list"
+
+parseStatement :: Parser Statement
+parseStatement =
+    (   try parseEdgeStatement
+    <|> try parseAttributeStatement
+    <|> try parseAssignmentStatement
+    <|> try parseSubgraphStatement
+    <|>     parseNodeStatement
+    )
+    <?> "statement"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseNodeStatement :: Parser Statement
+parseNodeStatement =
+    ( NodeStatement <$>
+      parseNodeId <*> parseAttributeList
+    )
+    <?> "node statement"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseEdgeStatement :: Parser Statement
+parseEdgeStatement =
+    ( EdgeStatement <$>
+      parseEntityList <*> parseAttributeList
+    )
+    <?> "edge statement"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseAttributeStatement :: Parser Statement
+parseAttributeStatement =
+    ( AttributeStatement <$>
+      parseAttributeStatementType <*> parseAttributeList
+    )
+    <?> "attribute statement"
+
+parseAttributeStatementType :: Parser AttributeStatementType
+parseAttributeStatementType =
+    (   (reserved' "graph" >> return GraphAttributeStatement)
+    <|> (reserved' "node"  >> return NodeAttributeStatement)
+    <|> (reserved' "edge"  >> return EdgeAttributeStatement)
+    )
+    <?> "attribute statement type"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseAssignmentStatement :: Parser Statement
+parseAssignmentStatement =
+    ( AssignmentStatement <$>
+      parseId <*> (reservedOp' "=" *> parseId)
+    )
+    <?> "assignment statement"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseSubgraphStatement :: Parser Statement
+parseSubgraphStatement =
+    ( SubgraphStatement <$>
+       parseSubgraph
+    )
+    <?> "subgraph statement"
+
+parseSubgraph :: Parser Subgraph
+parseSubgraph =
+    (   try parseNewSubgraph
+    <|>     parseSubgraphRef
+    )
+    <?> "subgraph"
+
+parseNewSubgraph :: Parser Subgraph
+parseNewSubgraph =
+    ( NewSubgraph <$>
+      (optional (reserved' "subgraph") *> optionMaybe parseId) <*> parseStatementList
+    )
+    <?> "new subgraph"
+
+parseSubgraphRef :: Parser Subgraph
+parseSubgraphRef =
+    ( SubgraphRef <$>
+      (reserved' "subgraph" *> parseId)
+    )
+    <?> "subgraph ref"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseEntityList :: Parser [Entity]
+parseEntityList =
+    ( (:) <$>
+      parseEntity True <*> many1 (parseEntity False)
+    )
+    <?> "entity list"
+
+parseEntity :: Bool -> Parser Entity
+parseEntity first =
+    (   try (parseENodeId first)
+    <|>     parseESubgraph first
+    )
+    <?> "entity"
+
+parseENodeId :: Bool -> Parser Entity
+parseENodeId first =
+    ( ENodeId <$>
+      (if first then return NoEdge else parseEdgeType) <*> parseNodeId
+    )
+    <?> "entity node id"
+
+parseESubgraph :: Bool -> Parser Entity
+parseESubgraph first =
+    ( ESubgraph <$>
+      (if first then return NoEdge else parseEdgeType) <*> parseSubgraph
+    )
+    <?> "entity subgraph"
+
+parseEdgeType :: Parser EdgeType
+parseEdgeType =
+    (   try (reservedOp' "->" >> return DirectedEdge)
+    <|>     (reservedOp' "--" >> return UndirectedEdge)
+    )
+    <?> "edge operator"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseNodeId :: Parser NodeId
+parseNodeId =
+    ( NodeId <$>
+      parseId <*> optionMaybe parsePort
+    )
+    <?> "node id"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parsePort :: Parser Port
+parsePort =
+    (   try parsePortC
+    <|>     parsePortI
+    )
+    <?> "port"
+
+parsePortC :: Parser Port
+parsePortC =
+    ( PortC <$>
+      (colon' *> parseCompass)
+    )
+    <?> "port (compass variant)"
+
+parsePortI :: Parser Port
+parsePortI =
+    ( PortI <$>
+      (colon' *> parseId) <*> optionMaybe (colon' *> parseCompass)
+    )
+    <?> "port (id variant)"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseCompass :: Parser Compass
+parseCompass =
+    (fmap convert identifier' >>= maybe err return)
+    <?> "compass"
+  where
+    err = parserFail "invalid compass value"
+    convert =
+        flip lookup table . stringToLower
+      where
+        table =
+          [ ("n",  CompassN),  ("e",  CompassE),  ("s",  CompassS),  ("w",  CompassW)
+          , ("ne", CompassNE), ("nw", CompassNW), ("se", CompassSE), ("sw", CompassSW)
+          ]
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseAttributeList :: Parser [Attribute]
+parseAttributeList =
+    (brackets' (parseAttribute `sepBy` optional comma') <|> return [])
+    <?> "attribute list"
+
+parseAttribute :: Parser Attribute
+parseAttribute =
+    ( do
+      id0 <- parseId
+      id1 <- optionMaybe (reservedOp' "=" >> parseId)
+      return $ maybe (AttributeSetTrue id0) (AttributeSetValue id0) id1
+    )
+    <?> "attribute"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseId :: Parser Id
+parseId =
+    (   try parseNameId
+    <|> try parseStringId
+    <|> try parseFloatId
+    <|> try parseIntegerId
+    <|>     parseXmlId
+    )
+    <?> "id"
+
+parseNameId :: Parser Id
+parseNameId =
+    ( NameId <$>
+      identifier'
+    )
+    <?> "name"
+
+parseStringId :: Parser Id
+parseStringId =
+    ( StringId <$>
+      lexeme' (char '"' *> manyTill stringChar (char '"'))
+    )
+    <?> "string literal"
+  where
+    stringChar =
+        (try (string "\\\"" >> return '"') <|> noneOf "\"")
+        <?> "string character"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+-- | DOT allows floating point numbers having no whole part like @.123@, but
+--   Parsec 'float' does not accept them.
+parseFloatId :: Parser Id
+parseFloatId =
+    lexeme'
+      ( do s <- parseSign
+           l <- fmap (fromMaybe 0) (optionMaybe parseNatural)
+           _ <- char '.'
+           r <- many1 digit
+           maybe err return (make s (show l ++ "." ++ r))
+      )
+    <?> "float"
+  where
+    err = parserFail "invalid float value"
+    make s f =
+        case readFloat f of
+          [(v,"")] -> (Just . FloatId . s) v
+          _        -> Nothing
+
+parseSign :: (Num a) => Parser (a -> a)
+parseSign =
+    (   (char '-' >> return negate)
+    <|> (char '+' >> return id)
+    <|> return id
+    )
+    <?> "sign"
+
+-- | Non-'lexeme' variant of 'natural' for parsing the natural part of a float.
+parseNatural :: Parser Integer
+parseNatural =
+    (   (char '0' >> return 0)
+    <|> (convert <$> many1 digit)
+    )
+    <?> "natural"
+  where
+    convert = foldl' (\acc d -> 10 * acc + fromIntegral (digitToInt d)) 0
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseIntegerId :: Parser Id
+parseIntegerId =
+    ( IntegerId <$>
+      integer'
+    )
+    <?> "integer"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parseXmlId :: Parser Id
+parseXmlId =
+    ( XmlId <$>
+      angles' parseXml
+    )
+    <?> "XML id"
+
+parseXml :: Parser Xml
+parseXml =
+    (   try parseXmlEmptyTag
+    <|> try parseXmlTag
+    <|>     parseXmlText
+    )
+    <?> "XML"
+
+parseXmlEmptyTag :: Parser Xml
+parseXmlEmptyTag =
+    ( XmlEmptyTag <$>
+      (char '<' *> parseXmlName) <*> (parseXmlAttributes <* (char '/' >> char '>'))
+    )
+    <?> "XML empty tag"
+
+parseXmlTag :: Parser Xml
+parseXmlTag =
+    ( do (name, attributes) <- parseXmlTagOpen
+         elements           <- manyTill parseXml (lookAhead (try (parseXmlTagClose (Just name))))
+         parseXmlTagClose (Just name)
+         return $ XmlTag name attributes elements
+    )
+    <?> "XML tag"
+
+parseXmlTagOpen :: Parser (XmlName, [XmlAttribute])
+parseXmlTagOpen =
+    ( (,) <$>
+      (char '<' *> parseXmlName) <*> (parseXmlAttributes <* char '>')
+    )
+    <?> "XML opening tag"
+
+parseXmlTagClose :: Maybe XmlName -> Parser ()
+parseXmlTagClose mn0 =
+    ( do _  <- char '<'
+         _  <- char '/'
+         n1 <- parseXmlName
+         _  <- char '>'
+         when (isJust mn0 && fromJust mn0 /= n1) parserZero
+    )
+    <?> "XML closing tag " ++ "(" ++ which ++ ")"
+  where
+    which =
+        case mn0 of
+          Just (XmlName n) -> "for " ++ show n
+          Nothing          -> "any"
+
+parseXmlText :: Parser Xml
+parseXmlText =
+    ( XmlText <$>
+      anyChar `manyTill` lookAhead (   try (parseXmlEmptyTag >> return ())
+                                   <|> try (parseXmlTag      >> return ())
+                                   <|>      parseXmlTagClose Nothing
+                                   )
+    )
+    <?> "XML text"
+
+parseXmlAttributes :: Parser [XmlAttribute]
+parseXmlAttributes =
+    many parseXmlAttribute
+    <?> "XML attribute list"
+
+parseXmlAttribute :: Parser XmlAttribute
+parseXmlAttribute =
+    ( XmlAttribute <$>
+      (parseXmlName <* reservedOp' "=") <*> parseXmlAttributeValue
+    )
+    <?> "XML attribute"
+
+parseXmlAttributeValue :: Parser XmlAttributeValue
+parseXmlAttributeValue =
+    ( XmlAttributeValue <$>
+      stringLiteral'
+    )
+    <?> "XML attribute value"
+
+parseXmlName :: Parser XmlName
+parseXmlName =
+    ( XmlName <$>
+      ((:) <$> c0 <*> (many c1 <* whiteSpace'))
+    )
+    <?> "XML name"
+  where
+    c0 = letter   <|> cs
+    c1 = alphaNum <|> cs
+    cs = oneOf "-.:_"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+angles'        :: Parser a -> Parser a
+braces'        :: Parser a -> Parser a
+brackets'      :: Parser a -> Parser a
+colon'         :: Parser String
+comma'         :: Parser String
+identifier'    :: Parser String
+integer'       :: Parser Integer
+lexeme'        :: Parser a -> Parser a
+reserved'      :: String -> Parser ()
+reservedOp'    :: String -> Parser ()
+semi'          :: Parser String
+stringLiteral' :: Parser String
+whiteSpace'    :: Parser ()
+
+angles'        = angles        lexer
+braces'        = braces        lexer
+brackets'      = brackets      lexer
+colon'         = colon         lexer
+comma'         = comma         lexer
+identifier'    = identifier    lexer
+integer'       = integer       lexer
+lexeme'        = lexeme        lexer
+reserved'      = reserved      lexer
+reservedOp'    = reservedOp    lexer
+semi'          = semi          lexer
+stringLiteral' = stringLiteral lexer
+whiteSpace'    = whiteSpace    lexer
+
+lexer :: TokenParser ()
+lexer =
+    makeTokenParser dotDef
+  where
+    dotDef = emptyDef
+      { commentStart    = "/*"
+      , commentEnd      = "*/"
+      , commentLine     = "//"
+      , nestedComments  = True
+      , identStart      = letter   <|> char '_'
+      , identLetter     = alphaNum <|> char '_'
+      , opStart         = oneOf "-="
+      , opLetter        = oneOf ""
+      , reservedOpNames = ["->", "--", "="]
+      , reservedNames   = ["digraph", "edge", "graph", "node", "strict", "subgraph"]
+      , caseSensitive   = False
+      }
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+stringToLower :: String -> String
+stringToLower = map toLower
diff --git a/Haskell-book/24/language-dot/src/Language/Dot/Pretty.hs b/Haskell-book/24/language-dot/src/Language/Dot/Pretty.hs
new file mode 100644
index 0000000..84a4c0c
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/Language/Dot/Pretty.hs
@@ -0,0 +1,135 @@
+module Language.Dot.Pretty
+  ( prettyPrintDot
+  , renderDot
+  , PP(..)
+  )
+  where
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+import Numeric
+import Text.PrettyPrint
+
+import Language.Dot.Syntax
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+prettyPrintDot :: Graph -> Doc
+prettyPrintDot = pp
+
+renderDot :: Graph -> String
+renderDot = render . pp
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+class PP a where
+  pp :: a -> Doc
+
+instance (PP a) => PP (Maybe a) where
+  pp (Just v) = pp v
+  pp Nothing  = empty
+
+instance PP Graph where
+  pp (Graph s d mi ss) = pp s <+> pp d <+> pp mi <+> lbrace $+$ indent (vcat' ss) $+$ rbrace
+
+instance PP GraphStrictness where
+  pp StrictGraph   = text "strict"
+  pp UnstrictGraph = empty
+
+instance PP GraphDirectedness where
+  pp DirectedGraph   = text "digraph"
+  pp UndirectedGraph = text "graph"
+
+instance PP Id where
+  pp (NameId v)    = text v
+  pp (StringId v)  = doubleQuotes (text v)
+  pp (IntegerId v) = integer v
+  pp (FloatId v)   = ffloat v
+  pp (XmlId v)     = langle <> pp v <> rangle
+
+instance PP Statement where
+  pp (NodeStatement ni as)       = pp ni <+> if not (null as) then brackets (hsep' as) else empty
+  pp (EdgeStatement es as)       = hsep' es <+> if not (null as) then brackets (hsep' as) else empty
+  pp (AttributeStatement t as)   = pp t <+> brackets (hsep' as)
+  pp (AssignmentStatement i0 i1) = pp i0 <> equals <> pp i1
+  pp (SubgraphStatement s)       = pp s
+
+instance PP AttributeStatementType where
+  pp GraphAttributeStatement = text "graph"
+  pp NodeAttributeStatement  = text "node"
+  pp EdgeAttributeStatement  = text "edge"
+
+instance PP Attribute where
+  pp (AttributeSetTrue i)      = pp i
+  pp (AttributeSetValue i0 i1) = pp i0 <> equals <> pp i1
+
+instance PP NodeId where
+  pp (NodeId i mp) = pp i <> pp mp
+
+instance PP Port where
+  pp (PortI i mc) = colon <> pp i <> maybe empty ((colon <>) . pp) mc
+  pp (PortC c)    = colon <> pp c
+
+instance PP Compass where
+  pp CompassN  = text "n"
+  pp CompassE  = text "e"
+  pp CompassS  = text "s"
+  pp CompassW  = text "w"
+  pp CompassNE = text "ne"
+  pp CompassNW = text "nw"
+  pp CompassSE = text "se"
+  pp CompassSW = text "sw"
+
+instance PP Subgraph where
+  pp (NewSubgraph mi ss) = text "subgraph" <+> pp mi <+> lbrace $+$ indent (vcat' ss) $+$ rbrace
+  pp (SubgraphRef i)     = text "subgraph" <+> pp i
+
+instance PP Entity where
+  pp (ENodeId et ni)   = pp et <+> pp ni
+  pp (ESubgraph et sg) = pp et <+> pp sg
+
+instance PP EdgeType where
+  pp NoEdge         = empty
+  pp DirectedEdge   = text "->"
+  pp UndirectedEdge = text "--"
+
+instance PP Xml where
+  pp (XmlEmptyTag n as) = langle <> pp n <+> hsep' as <> slash <> rangle
+  pp (XmlTag n as xs)   = langle <> pp n <+> hsep' as <> rangle <> hcat' xs <> langle <> slash <> pp n <> rangle
+  pp (XmlText t)        = text t
+
+instance PP XmlName where
+  pp (XmlName n) = text n
+
+instance PP XmlAttribute where
+  pp (XmlAttribute n v) = pp n <> equals <> pp v
+
+instance PP XmlAttributeValue where
+  pp (XmlAttributeValue v) = doubleQuotes (text v)
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+indent :: Doc -> Doc
+indent = nest 2
+
+hcat' :: (PP a) => [a] -> Doc
+hcat' = hcat . map pp
+
+hsep' :: (PP a) => [a] -> Doc
+hsep' = hsep . map pp
+
+vcat' :: (PP a) => [a] -> Doc
+vcat' = vcat . map pp
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+langle :: Doc
+rangle :: Doc
+slash  :: Doc
+
+langle = char '<'
+rangle = char '>'
+slash  = char '/'
+
+ffloat :: Float -> Doc
+ffloat v = text (showFFloat Nothing v "")
diff --git a/Haskell-book/24/language-dot/src/Language/Dot/Syntax.hs b/Haskell-book/24/language-dot/src/Language/Dot/Syntax.hs
new file mode 100644
index 0000000..cca7d99
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/Language/Dot/Syntax.hs
@@ -0,0 +1,92 @@
+-- | DOT AST. See <http://www.graphviz.org/doc/info/lang.html>.
+
+module Language.Dot.Syntax where
+
+data Graph
+  = Graph GraphStrictness GraphDirectedness (Maybe Id) [Statement]
+  deriving (Eq, Show)
+
+data GraphStrictness
+  = StrictGraph
+  | UnstrictGraph
+  deriving (Eq, Show)
+
+data GraphDirectedness
+  = DirectedGraph
+  | UndirectedGraph
+  deriving (Eq, Show)
+
+data Id
+  = NameId    String
+  | StringId  String
+  | IntegerId Integer
+  | FloatId   Float
+  | XmlId     Xml
+  deriving (Eq, Show)
+
+data Statement
+  = NodeStatement       NodeId [Attribute]
+  | EdgeStatement       [Entity] [Attribute]
+  | AttributeStatement  AttributeStatementType [Attribute]
+  | AssignmentStatement Id Id
+  | SubgraphStatement   Subgraph
+  deriving (Eq, Show)
+
+data AttributeStatementType
+  = GraphAttributeStatement
+  | NodeAttributeStatement
+  | EdgeAttributeStatement
+  deriving (Eq, Show)
+
+data Attribute
+  = AttributeSetTrue  Id
+  | AttributeSetValue Id Id
+  deriving (Eq, Show)
+
+data NodeId
+  = NodeId Id (Maybe Port)
+  deriving (Eq, Show)
+
+data Port
+  = PortI Id (Maybe Compass)
+  | PortC Compass
+  deriving (Eq, Show)
+
+data Compass
+  = CompassN  | CompassE  | CompassS  | CompassW
+  | CompassNE | CompassNW | CompassSE | CompassSW
+  deriving (Eq, Show)
+
+data Subgraph
+  = NewSubgraph (Maybe Id) [Statement]
+  | SubgraphRef Id
+  deriving (Eq, Show)
+
+data Entity
+  = ENodeId   EdgeType NodeId
+  | ESubgraph EdgeType Subgraph
+  deriving (Eq, Show)
+
+data EdgeType
+  = NoEdge
+  | DirectedEdge
+  | UndirectedEdge
+  deriving (Eq, Show)
+
+data Xml
+  = XmlEmptyTag XmlName [XmlAttribute]
+  | XmlTag      XmlName [XmlAttribute] [Xml]
+  | XmlText     String
+  deriving (Eq, Show)
+
+data XmlName
+  = XmlName String
+  deriving (Eq, Show)
+
+data XmlAttribute
+  = XmlAttribute XmlName XmlAttributeValue
+  deriving (Eq, Show)
+
+data XmlAttributeValue
+  = XmlAttributeValue String
+  deriving (Eq, Show)
diff --git a/Haskell-book/24/language-dot/src/ppdot.hs b/Haskell-book/24/language-dot/src/ppdot.hs
new file mode 100644
index 0000000..6051845
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/ppdot.hs
@@ -0,0 +1,72 @@
+module Main (main) where
+
+import Control.Exception   (IOException, try)
+import Control.Monad.Error (ErrorT(..), MonadError(..))
+import System.Environment  (getArgs, getProgName)
+import System.Exit         (exitFailure, exitSuccess)
+import System.IO           (hPutStrLn, stderr)
+
+import Language.Dot (parseDot, renderDot)
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+main :: IO ()
+main =
+    getArgs >>= run
+
+run :: [String] -> IO ()
+run args =
+    case args of
+      [fp] -> renderDotFile fp
+      []   -> displayUsage >> exitSuccess
+      _    -> displayUsage >> exitFailure
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+renderDotFile :: FilePath -> IO ()
+renderDotFile fp =
+    runErrorT (renderDotFileET fp) >>= either exitError putStrLn
+
+renderDotFileET :: FilePath -> ErrorT String IO String
+renderDotFileET fp = do
+    contents <- readFile fp `liftCatch` show
+    graph    <- parseDot fp contents `liftEither` show
+    return $ renderDot graph
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+displayUsage :: IO ()
+displayUsage = do
+    programName <- getProgName
+    ePutStrLns
+      [ programName ++ ": Pretty-print a Graphviz DOT file."
+      , unwords ["Usage:", programName, "FILE"]
+      ]
+
+exitError :: String -> IO ()
+exitError e = do
+    displayUsage
+    ePutStrLn ""
+    let el = lines e
+    if length el == 1
+      then ePutStrLn  ("ERROR: " ++ e)
+      else ePutStrLns ("ERROR:" : indent el)
+    exitFailure
+  where
+    indent = map ("  "++)
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+liftCatch :: IO a -> (IOException -> e) -> ErrorT e IO a
+liftCatch a f = ErrorT $ fmap (either (Left . f) Right) (try a)
+
+liftEither :: (MonadError e m) => Either l r -> (l -> e) -> m r
+liftEither e f = either (throwError . f) return e
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+ePutStrLn :: String -> IO ()
+ePutStrLn = hPutStrLn stderr
+
+ePutStrLns :: [String] -> IO ()
+ePutStrLns = mapM_ (hPutStrLn stderr)
diff --git a/Haskell-book/24/language-dot/src/test.hs b/Haskell-book/24/language-dot/src/test.hs
new file mode 100644
index 0000000..2fa4e0b
--- /dev/null
+++ b/Haskell-book/24/language-dot/src/test.hs
@@ -0,0 +1,120 @@
+module Main (main) where
+
+import Control.Monad (unless)
+import Data.Char     (toLower, toUpper)
+
+import Text.Parsec
+import Text.Parsec.String
+
+import Language.Dot.Parser
+import Language.Dot.Syntax
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+main :: IO ()
+main = do
+    testParser "parsePort"      parsePort      parsePortTests
+    testParser "parseCompass"   parseCompass   parseCompassTests
+    testParser "parseAttribute" parseAttribute parseAttributeTests
+    testParser "parseId"        parseId        parseIdTests
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parsePortTests :: [(String, Port)]
+parsePortTests =
+    [ ( ":\"x\""          , PortI (StringId  "x"       ) Nothing          )
+    , ( ":\"\\t\\\"\":nw" , PortI (StringId  "\\t\""   ) (Just CompassNW) )
+    , ( ":-.0004"         , PortI (FloatId   (-0.0004) ) Nothing          )
+    , ( ":-1.23:sE"       , PortI (FloatId   (-1.23)   ) (Just CompassSE) )
+    , ( ":123"            , PortI (IntegerId 123       ) Nothing          )
+    , ( ":123:NE"         , PortI (IntegerId 123       ) (Just CompassNE) )
+    , ( ":__2xYz"         , PortI (NameId    "__2xYz"  ) Nothing          )
+    , ( ":__2xYz:S"       , PortI (NameId    "__2xYz"  ) (Just CompassS)  )
+    , ( ":n"              , PortC CompassN  )
+    , ( ":SE"             , PortC CompassSE )
+    ]
+
+parseCompassTests :: [(String, Compass)]
+parseCompassTests =
+    concat
+      [ [ (t, CompassN)  | t <- allCaps "n"  ]
+      , [ (t, CompassE)  | t <- allCaps "e"  ]
+      , [ (t, CompassS)  | t <- allCaps "s"  ]
+      , [ (t, CompassW)  | t <- allCaps "w"  ]
+      , [ (t, CompassNE) | t <- allCaps "ne" ]
+      , [ (t, CompassNW) | t <- allCaps "nw" ]
+      , [ (t, CompassSE) | t <- allCaps "se" ]
+      , [ (t, CompassSW) | t <- allCaps "sw" ]
+      ]
+
+parseAttributeTests :: [(String, Attribute)]
+parseAttributeTests =
+    [ ( "a"                      , AttributeSetTrue  (NameId "a")                           )
+    , ( "a=b"                    , AttributeSetValue (NameId "a")       (NameId "b")        )
+    , ( "-.003\t=\r\n  _xYz123_" , AttributeSetValue (FloatId (-0.003)) (NameId "_xYz123_") )
+    , ( "\"\\t\\\"\"  =-123"     , AttributeSetValue (StringId "\\t\"") (IntegerId (-123))  )
+    ]
+
+parseIdTests :: [(String, Id)]
+parseIdTests =
+    [ ( "a"             , NameId    "a"         )
+    , ( "A1"            , NameId    "A1"        )
+    , ( "_2X"           , NameId    "_2X"       )
+    , ( "\"\""          , StringId  ""          )
+    , ( "\"\\t\\r\\n\"" , StringId  "\\t\\r\\n" )
+    , ( ".0"            , FloatId   0.0         )
+    , ( ".123"          , FloatId   0.123       )
+    , ( "+.999"         , FloatId   0.999       )
+    , ( "-.001"         , FloatId   (-0.001)    )
+    , ( "+.001"         , FloatId   0.001       )
+    , ( "0.0"           , FloatId   0.0         )
+    , ( "1.2"           , FloatId   1.2         )
+    , ( "123.456"       , FloatId   123.456     )
+    , ( "0"             , IntegerId 0           )
+    , ( "+0"            , IntegerId 0           )
+    , ( "-0"            , IntegerId 0           )
+    , ( "123"           , IntegerId 123         )
+    , ( "-123"          , IntegerId (-123)      )
+    ]
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+testParser :: (Eq a, Show a) => String -> Parser a -> [(String, a)] -> IO ()
+testParser name parser tests =
+    help tests [] (0 :: Int) (0 :: Int)
+  where
+    help [] es np nf = do
+        putStrLn $ name ++ ": " ++ show np ++ " passed, " ++ show nf ++ " failed"
+        mapM_ (putStrLn . ("  "++)) (reverse es)
+        unless (null es) (putStrLn "")
+    help ((i,o):ts) es np nf =
+        case parse' parser i of
+          Left  _ -> help ts (makeFailureMessage name i o : es) np (succ nf)
+          Right v ->
+            if v /= o
+              then help ts (makeFailureMessage' name i o v : es) np (succ nf)
+              else help ts es (succ np) nf
+
+makeFailureMessage :: (Show a) => String -> String -> a -> String
+makeFailureMessage name i o =
+    "(" ++ name ++ " " ++ show i ++ ")" ++
+    " should have returned " ++ "(" ++ show o ++ ")"
+
+makeFailureMessage' :: (Show a) => String -> String -> a -> a -> String
+makeFailureMessage' name i o v =
+    "(" ++ name ++ " " ++ show i ++ ")" ++
+    " returned "  ++ "(" ++ show v ++ ")" ++
+    ", expected " ++ "(" ++ show o ++ ")"
+
+-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
+
+parse' :: Parser a -> String -> Either ParseError a
+parse' p = parse p ""
+
+allCaps :: String -> [String]
+allCaps []     = [[]]
+allCaps (c:cs) =
+    concatMap (\t -> [l:t, u:t]) (allCaps cs)
+  where
+    l = toLower c
+    u = toUpper c
diff --git a/Haskell-book/25/Bifunctor/.gitignore b/Haskell-book/25/Bifunctor/.gitignore
new file mode 100644
index 0000000..45b62d9
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Bifunctor.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/25/Bifunctor/Setup.hs b/Haskell-book/25/Bifunctor/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/25/Bifunctor/package.yaml b/Haskell-book/25/Bifunctor/package.yaml
new file mode 100644
index 0000000..0f52279
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/package.yaml
@@ -0,0 +1,23 @@
+name:                Bifunctor
+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:
+  Bifunctor-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Bifunctor
diff --git a/Haskell-book/25/Bifunctor/src/Bifunctor.hs b/Haskell-book/25/Bifunctor/src/Bifunctor.hs
new file mode 100644
index 0000000..944bf13
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/src/Bifunctor.hs
@@ -0,0 +1,68 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+module Bifunctor where
+
+import Prelude (($), id, (.))
+
+class Bifunctor p where
+    {-# MINIMAL bimap | first, second #-}
+
+    bimap :: (a -> b)
+          -> (c -> d)
+          -> p a c
+          -> p b d
+    bimap f g = first f . second g
+
+    first :: (a -> b) -> p a c -> p b c
+    first f = bimap f id
+
+    second :: (b -> c) -> p a b -> p a c
+    second = bimap id
+
+-- 1
+data Deux a b = Deux a b
+
+instance Bifunctor Deux where
+    first f (Deux a c) = Deux (f a) c
+    second f (Deux a b) = Deux a (f b)
+
+-- 2
+data Const a b = Const a
+
+instance Bifunctor Const where
+    first f (Const a) = Const (f a)
+    second f (Const a) = Const a
+
+-- 3
+data Drei a b c = Drei a b c
+
+instance Bifunctor (Drei a) where
+    first f (Drei a b c) = Drei a (f b) c
+    second f (Drei a b c) = Drei a b (f c)
+
+-- 4
+data SuperDrei a b c = SuperDrei a b
+
+instance Bifunctor (SuperDrei a) where
+    first f (SuperDrei a b) = SuperDrei a (f b)
+    second f (SuperDrei a b) = SuperDrei a b
+
+-- 5
+data SemiDrei a b c = SemiDrei a
+
+instance Bifunctor (SemiDrei a) where
+    first f (SemiDrei a) = SemiDrei a
+    second f (SemiDrei a) = SemiDrei a
+
+-- 6
+data Quadriceps a b c d = Quadzzz a b c d
+
+instance Bifunctor (Quadriceps a b) where
+    first f (Quadzzz a b c d) = Quadzzz a b (f c) d
+    second f (Quadzzz a b c d) = Quadzzz a b c (f d)
+
+-- 7
+data Either a b = Left a | Right b
+
+instance Bifunctor Either where
+    first f (Left a) = Left $ f a
+    second f (Right b) = Right $ f b
\ No newline at end of file
diff --git a/Haskell-book/25/Bifunctor/stack.yaml b/Haskell-book/25/Bifunctor/stack.yaml
new file mode 100644
index 0000000..05facc0
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/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-11.6
+
+# 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/25/Bifunctor/test/Spec.hs b/Haskell-book/25/Bifunctor/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/Haskell-book/25/Bifunctor/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/Haskell-book/25/Twinplicative/.gitignore b/Haskell-book/25/Twinplicative/.gitignore
new file mode 100644
index 0000000..33823d2
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Twinplicative.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/25/Twinplicative/LICENSE b/Haskell-book/25/Twinplicative/LICENSE
new file mode 100644
index 0000000..e037c72
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/LICENSE
@@ -0,0 +1,30 @@
+Copyright Author name here (c) 2018
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Haskell-book/25/Twinplicative/Setup.hs b/Haskell-book/25/Twinplicative/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/25/Twinplicative/package.yaml b/Haskell-book/25/Twinplicative/package.yaml
new file mode 100644
index 0000000..0c1eed0
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/package.yaml
@@ -0,0 +1,13 @@
+name:                Twinplicative
+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
\ No newline at end of file
diff --git a/Haskell-book/25/Twinplicative/src/Twinplicative.hs b/Haskell-book/25/Twinplicative/src/Twinplicative.hs
new file mode 100644
index 0000000..f8840fa
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/src/Twinplicative.hs
@@ -0,0 +1,42 @@
+{-# LANGUAGE InstanceSigs #-}
+module Twinplicative where
+
+newtype Identity a
+      = Identity { runIdentity :: a }
+
+instance Functor Identity where
+      fmap f (Identity a) = Identity (f a)
+
+newtype Compose f g a =
+      Compose { getCompose :: f (g a) }
+      deriving (Eq, Show)
+
+instance (Functor f, Functor g) =>
+          Functor (Compose f g) where
+      fmap f (Compose fga) =
+            Compose $ (fmap . fmap) f fga
+
+-- instance types provided as they may help.
+instance (Applicative f, Applicative g)
+       => Applicative (Compose f g) where
+    pure :: a -> Compose f g a
+    pure x = Compose $ (pure . pure) x
+
+    (<*>) :: Compose f g (a -> b)
+          -> Compose f g a
+          -> Compose f g b
+    (Compose f) <*> (Compose a) = Compose $ (fmap (<*>) f) <*> a
+
+
+instance (Foldable f, Foldable g) =>
+    Foldable (Compose f g) where
+      foldMap f (Compose fga) =
+        (foldMap . foldMap) f fga
+
+instance (Traversable f, Traversable g) =>
+    Traversable (Compose f g) where
+      traverse :: Applicative f1 => (a -> f1 b)
+               -> Compose f g a
+               -> f1 (Compose f g b)
+      traverse f (Compose fga) =
+        Compose <$> (traverse . traverse) f fga
\ No newline at end of file
diff --git a/Haskell-book/25/Twinplicative/stack.yaml b/Haskell-book/25/Twinplicative/stack.yaml
new file mode 100644
index 0000000..05facc0
--- /dev/null
+++ b/Haskell-book/25/Twinplicative/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-11.6
+
+# 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/26/Embedded/Embedded.cabal b/Haskell-book/26/Embedded/Embedded.cabal
new file mode 100644
index 0000000..d0898f4
--- /dev/null
+++ b/Haskell-book/26/Embedded/Embedded.cabal
@@ -0,0 +1,40 @@
+-- This file has been generated from package.yaml by hpack version 0.20.0.
+--
+-- see: https://github.com/sol/hpack
+--
+-- hash: 4aaf9c578000b87231817edc542c283c58e2e1562cc290df37e9e8a9628885b0
+
+name:           Embedded
+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
+    , transformers
+  exposed-modules:
+      OuterInner
+  other-modules:
+      Paths_Embedded
+  default-language: Haskell2010
+
+test-suite Embedded-test
+  type: exitcode-stdio-1.0
+  main-is: Spec.hs
+  hs-source-dirs:
+      test
+  ghc-options: -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+      Embedded
+    , base >=4.7 && <5
+    , transformers
+  other-modules:
+      Paths_Embedded
+  default-language: Haskell2010
diff --git a/Haskell-book/26/Embedded/Setup.hs b/Haskell-book/26/Embedded/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/26/Embedded/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/26/Embedded/package.yaml b/Haskell-book/26/Embedded/package.yaml
new file mode 100644
index 0000000..59f144a
--- /dev/null
+++ b/Haskell-book/26/Embedded/package.yaml
@@ -0,0 +1,24 @@
+name:                Embedded
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- transformers
+
+library:
+  source-dirs: src
+
+tests:
+  Embedded-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Embedded
diff --git a/Haskell-book/26/Embedded/src/OuterInner.hs b/Haskell-book/26/Embedded/src/OuterInner.hs
new file mode 100644
index 0000000..edc31c1
--- /dev/null
+++ b/Haskell-book/26/Embedded/src/OuterInner.hs
@@ -0,0 +1,30 @@
+module OuterInner where
+
+import Control.Monad.Trans.Except
+import Control.Monad.Trans.Maybe
+import Control.Monad.Trans.Reader
+
+-- We only need to use return once
+-- because it's one big Monad
+embedded :: MaybeT
+            (ExceptT String
+                    (ReaderT () IO))
+            Int
+--embedded = return 1
+embedded = MaybeT . ExceptT . ReaderT $ return . (const (Right (Just 1)))
+
+-- We can sort of peel away the layers one by one:
+maybeUnwrap :: ExceptT String
+               (ReaderT () IO) (Maybe Int)
+maybeUnwrap = runMaybeT embedded
+
+-- Next
+eitherUnwrap :: ReaderT () IO
+                (Either String (Maybe Int))
+eitherUnwrap = runExceptT maybeUnwrap
+
+-- Lastly
+readerUnwrap :: ()
+             -> IO (Either String
+                           (Maybe Int))
+readerUnwrap = runReaderT eitherUnwrap
\ No newline at end of file
diff --git a/Haskell-book/26/Embedded/stack.yaml b/Haskell-book/26/Embedded/stack.yaml
new file mode 100644
index 0000000..eb506f9
--- /dev/null
+++ b/Haskell-book/26/Embedded/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-11.7
+
+# 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/26/Embedded/test/Spec.hs b/Haskell-book/26/Embedded/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/Haskell-book/26/Embedded/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/Haskell-book/26/Exercises/.gitignore b/Haskell-book/26/Exercises/.gitignore
new file mode 100644
index 0000000..3834f98
--- /dev/null
+++ b/Haskell-book/26/Exercises/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Exercises.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/26/Exercises/Setup.hs b/Haskell-book/26/Exercises/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/26/Exercises/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/26/Exercises/app/Main.hs b/Haskell-book/26/Exercises/app/Main.hs
new file mode 100644
index 0000000..6bfe6bb
--- /dev/null
+++ b/Haskell-book/26/Exercises/app/Main.hs
@@ -0,0 +1,61 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Main where
+
+import Control.Monad.IO.Class
+import Control.Monad.Trans.Class
+import Control.Monad.Trans.Reader
+import Data.IORef
+import qualified Data.Map as M
+import Data.Maybe (fromMaybe)
+import Data.Text.Lazy (Text)
+import qualified Data.Text.Lazy as TL
+import System.Environment (getArgs)
+import Web.Scotty.Trans ( ScottyT(..)
+                        , ActionT(..)
+                        , scottyT
+                        , get
+                        , html
+                        , param )
+
+data Config =
+    Config {
+        -- that's one, one click!
+        -- two...two clicks!
+        -- Three BEAUTIFUL clicks! ah ah ahhhh
+        counts :: IORef (M.Map Text Integer)
+      , prefix :: Text
+    }
+
+type Scotty = ScottyT Text (ReaderT Config IO)
+
+bumpBoomp :: Text
+    -> M.Map Text Integer
+    -> (M.Map Text Integer, Integer)
+bumpBoomp k m =
+    let (maybeCount, newMap) = M.insertLookupWithKey (\_ _ oldCount -> oldCount + 1) k 1 m
+    in case maybeCount of
+        Nothing -> (newMap, 1)
+        Just oldCount -> (newMap, oldCount + 1)
+
+app :: Scotty ()
+app =
+    get "/:key" $ do
+        unprefixed <- param "key"
+        prefix <- lift $ asks prefix
+        let key' = mappend prefix unprefixed
+        counts <- lift $ asks counts
+        (newMap, newInteger) <- liftIO $ bumpBoomp key' <$> readIORef counts
+        liftIO $ writeIORef counts newMap
+        html $ mconcat [ "<h1>Success! Count was: "
+                       , TL.pack $ show (newInteger :: Integer)
+                       , "</h1>"
+                       ]
+
+main :: IO ()
+main = do
+    [prefixArg] <- getArgs
+    counter <- newIORef M.empty
+    let config = Config {counts = counter, prefix = TL.pack prefixArg}
+        runR = flip runReaderT config
+    scottyT 3000 runR app
diff --git a/Haskell-book/26/Exercises/package.yaml b/Haskell-book/26/Exercises/package.yaml
new file mode 100644
index 0000000..a757233
--- /dev/null
+++ b/Haskell-book/26/Exercises/package.yaml
@@ -0,0 +1,37 @@
+name:                Exercises
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- containers
+- scotty
+- transformers
+- text
+
+library:
+  source-dirs: src
+
+executables:
+  HitCounter:
+    main:        Main.hs
+    source-dirs: app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+
+tests:
+  Exercises-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - Exercises
+    - hspec
diff --git a/Haskell-book/26/Exercises/src/Exercises.hs b/Haskell-book/26/Exercises/src/Exercises.hs
new file mode 100644
index 0000000..d3a8370
--- /dev/null
+++ b/Haskell-book/26/Exercises/src/Exercises.hs
@@ -0,0 +1,75 @@
+module Exercises where
+
+import Control.Monad.IO.Class (liftIO)
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Reader (Reader(..), ReaderT(..), runReader, runReaderT)
+import Control.Monad.Trans.State (StateT(..))
+import Data.Functor.Identity (Identity(..))
+
+-- 1. rDec is a function that should get its argument in the context of
+-- Reader and return a value decremented by one.
+--
+-- Note that “Reader” from transformers is ReaderT of Identity and
+-- that runReader is a convenience function throwing away the
+-- meaningless structure for you. Play with runReaderT if you like.
+rDec :: Num a => Reader a a
+rDec = ReaderT $ dec
+    where dec :: Num a => a -> Identity a
+          dec = return . (flip (-) 1)
+
+-- 2. Once you have an rDec that works, make it and any inner lamb-
+-- das pointfree if that’s not already the case.
+
+
+-- 3. rShow is show, but in Reader.
+rShow :: Show a => Reader a String
+rShow = ReaderT $ toString
+    where toString = return . show
+
+-- 4. Once you have an rShow that works, make it pointfree.
+
+
+-- 5. rPrintAndInc will first print the input with a greeting, then return
+-- the input incremented by one.
+rPrintAndInc :: (Num a, Show a) => ReaderT a IO a
+rPrintAndInc = ReaderT print
+    where print x = do
+            liftIO $ putStrLn $ "Hi: " ++ show x
+            return $ x + 1
+
+-- Prelude> runReaderT rPrintAndInc 1
+-- Hi: 1
+-- 2
+-- Prelude> traverse (runReaderT rPrintAndInc) [1..10]
+-- Hi: 1
+-- Hi: 2
+-- Hi: 3
+-- Hi: 4
+-- Hi: 5
+-- Hi: 6
+-- Hi: 7
+-- Hi: 8
+-- Hi: 9
+-- Hi: 10
+-- [2,3,4,5,6,7,8,9,10,11]
+
+
+-- 6. sPrintIncAccum first prints the input with a greeting, then puts
+-- the incremented input as the new state, and returns the original
+-- input as a String.
+sPrintIncAccum :: (Num a, Show a) => StateT a IO String
+sPrintIncAccum = StateT print
+    where print x = do
+            liftIO $ putStrLn $ "Hi: " ++ show x
+            return $ (show x, x + 1)
+
+-- Prelude> runStateT sPrintIncAccum 10
+-- Hi: 10
+-- ("10",11)
+-- Prelude> mapM (runStateT sPrintIncAccum) [1..5]
+-- Hi: 1
+-- Hi: 2
+-- Hi: 3
+-- Hi: 4
+-- Hi: 5
+-- [("1",2),("2",3),("3",4),("4",5),("5",6)]
diff --git a/Haskell-book/26/Exercises/src/Fix.hs b/Haskell-book/26/Exercises/src/Fix.hs
new file mode 100644
index 0000000..bd43f7f
--- /dev/null
+++ b/Haskell-book/26/Exercises/src/Fix.hs
@@ -0,0 +1,24 @@
+module Fix where
+
+import Control.Monad.IO.Class (liftIO)
+import Control.Monad.Trans.Maybe
+import Control.Monad
+
+isValid :: String -> Bool
+isValid v = '!' `elem` v
+
+maybeExcite :: MaybeT IO String
+maybeExcite = do
+    v <- liftIO getLine
+    guard $ isValid v
+    return v
+
+doExcite :: IO ()
+doExcite = do
+    putStrLn "say something excite!"
+    excite <- runMaybeT maybeExcite
+    case excite of
+      Nothing -> putStrLn "MOAR EXCITE"
+      Just e ->
+          putStrLn
+            ("Good, was very excite: " ++ e)
diff --git a/Haskell-book/26/Exercises/stack.yaml b/Haskell-book/26/Exercises/stack.yaml
new file mode 100644
index 0000000..1962baa
--- /dev/null
+++ b/Haskell-book/26/Exercises/stack.yaml
@@ -0,0 +1,65 @@
+# 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
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-11.8
+
+# 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
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (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: ">=1.7"
+#
+# 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/26/Exercises/test/Spec.hs b/Haskell-book/26/Exercises/test/Spec.hs
new file mode 100644
index 0000000..92db8e6
--- /dev/null
+++ b/Haskell-book/26/Exercises/test/Spec.hs
@@ -0,0 +1,19 @@
+import Control.Monad.Trans.Reader
+import Exercises
+import Test.Hspec
+
+main :: IO ()
+main = hspec $ do
+    describe "rDec" $ do
+        it "returns a value decremented by one" $ do
+            runReader rDec 1 `shouldBe` 0
+
+        it "decrements all elements of a list" $ do
+            (fmap (runReader rDec) [1..10]) `shouldBe` [0,1,2,3,4,5,6,7,8,9]
+
+    describe "rShow" $ do
+        it "shows a number" $ do
+            runReader rShow 1 `shouldBe` "1"
+
+        it "shows a list" $ do
+            (fmap (runReader rShow) [1..10]) `shouldBe` ["1","2","3","4","5","6","7","8","9","10"]
diff --git a/Haskell-book/26/MaybeT/.gitignore b/Haskell-book/26/MaybeT/.gitignore
new file mode 100644
index 0000000..ae82431
--- /dev/null
+++ b/Haskell-book/26/MaybeT/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+MaybeT.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/26/MaybeT/Setup.hs b/Haskell-book/26/MaybeT/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/26/MaybeT/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/26/MaybeT/package.yaml b/Haskell-book/26/MaybeT/package.yaml
new file mode 100644
index 0000000..dfa5dac
--- /dev/null
+++ b/Haskell-book/26/MaybeT/package.yaml
@@ -0,0 +1,23 @@
+name:                MaybeT
+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:
+  MaybeT-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - MaybeT
diff --git a/Haskell-book/26/MaybeT/src/Either.hs b/Haskell-book/26/MaybeT/src/Either.hs
new file mode 100644
index 0000000..e09bfe6
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/Either.hs
@@ -0,0 +1,56 @@
+module Either where
+
+import Control.Monad (liftM)
+import MonadTrans
+import MonadIO
+
+newtype EitherT e m a =
+    EitherT { runEitherT :: m (Either e a) }
+
+-- 1
+instance Functor m => Functor (EitherT e m) where
+    fmap f (EitherT x) = EitherT $ (fmap . fmap) f x
+
+-- 2
+instance Applicative m => Applicative (EitherT e m) where
+    pure x = EitherT $ pure $ pure x
+
+    (EitherT f) <*> (EitherT a) = EitherT $ (<*>) <$> f <*> a
+
+-- 3
+instance Monad m => Monad (EitherT e m) where
+    return = pure
+
+    (EitherT em) >>= f = EitherT $ do
+        v <- em
+        case v of
+            Left y -> return $ Left y
+            Right y -> runEitherT (f y)
+
+
+-- 4
+-- transformer version of swapEither.
+-- Hint: write swapEither first, then swapEitherT in terms of the former.
+swapEither :: Either e a -> Either a e
+swapEither (Left x) = Right x
+swapEither (Right y) = Left y
+
+swapEitherT :: (Functor m)
+            => EitherT e m a
+            -> EitherT a m e
+swapEitherT (EitherT x) = EitherT $ fmap swapEither x
+
+-- 5. Write the transformer variant of the either catamorphism.
+eitherT :: Monad m
+        => (a -> m c)
+        -> (b -> m c)
+        -> EitherT a m b
+        -> m c
+eitherT f g (EitherT x) = x >>= (either f g)
+
+instance MonadTrans (EitherT e) where
+    lift = EitherT . liftM Right
+
+instance (MonadIO m)
+  => MonadIO (EitherT e m) where
+      liftIO = lift . liftIO
diff --git a/Haskell-book/26/MaybeT/src/Identity.hs b/Haskell-book/26/MaybeT/src/Identity.hs
new file mode 100644
index 0000000..8189c18
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/Identity.hs
@@ -0,0 +1,43 @@
+module Identity where
+
+import MonadIO
+import MonadTrans
+
+newtype Identity a =
+    Identity { runIdentity :: a }
+    deriving (Eq, Show)
+
+instance Functor Identity where
+    fmap f (Identity a) = Identity (f a)
+
+instance Applicative Identity where
+    pure = Identity
+    (Identity f) <*> (Identity a) = Identity (f a)
+
+newtype IdentityT f a =
+    IdentityT { runIdentityT :: f a }
+    deriving (Eq, Show)
+
+instance (Functor m)
+  => Functor (IdentityT m) where
+      fmap f (IdentityT fa) = IdentityT (fmap f fa)
+
+instance (Applicative m)
+  => Applicative (IdentityT m) where
+      pure x = IdentityT (pure x)
+
+      (IdentityT fab) <*> (IdentityT fa) =
+          IdentityT (fab <*> fa)
+
+instance (Monad m)
+  => Monad (IdentityT m) where
+      return = pure
+
+      (IdentityT ma) >>= f = IdentityT $ ma >>= runIdentityT . f
+
+instance (MonadIO m)
+  => MonadIO (IdentityT m) where
+      liftIO = IdentityT . liftIO
+
+instance MonadTrans IdentityT where
+    lift = IdentityT
diff --git a/Haskell-book/26/MaybeT/src/Maybe.hs b/Haskell-book/26/MaybeT/src/Maybe.hs
new file mode 100644
index 0000000..4d6c9b7
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/Maybe.hs
@@ -0,0 +1,40 @@
+module Maybe where
+
+import Control.Monad
+import MonadIO
+import MonadTrans
+
+newtype MaybeT m a =
+    MaybeT { runMaybeT :: m (Maybe a) }
+
+-- compare to the instance for MaybeT
+instance (Functor m)
+      => Functor (MaybeT m) where
+        fmap f (MaybeT ma) =
+            MaybeT $ (fmap . fmap) f ma
+
+instance (Applicative m)
+      => Applicative (MaybeT m) where
+        pure x = MaybeT (pure (pure x))
+
+        (MaybeT fab) <*> (MaybeT mma) = MaybeT $ (<*>) <$> fab <*> mma
+
+instance (Monad m)
+      => Monad (MaybeT m) where
+        return = pure
+
+        -- (>>=) :: MaybeT m a -> (a -> MaybeT m b) -> MaybeT m b
+        (MaybeT ma) >>= f = MaybeT $ do
+            -- ma :: m (Maybe a)
+            -- v :: Maybe a
+            v <- ma
+            case v of
+                Nothing -> return Nothing
+                Just y -> runMaybeT (f y)
+
+instance MonadTrans MaybeT where
+    lift = MaybeT . liftM Just
+
+instance (MonadIO m)
+  => MonadIO (MaybeT m) where
+      liftIO = lift . liftIO
diff --git a/Haskell-book/26/MaybeT/src/MonadIO.hs b/Haskell-book/26/MaybeT/src/MonadIO.hs
new file mode 100644
index 0000000..93244dd
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/MonadIO.hs
@@ -0,0 +1,5 @@
+module MonadIO where
+
+class (Monad m) => MonadIO m where
+    -- | Lift a computation from the 'IO' monad.
+    liftIO :: IO a -> m a
diff --git a/Haskell-book/26/MaybeT/src/MonadTrans.hs b/Haskell-book/26/MaybeT/src/MonadTrans.hs
new file mode 100644
index 0000000..7954164
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/MonadTrans.hs
@@ -0,0 +1,7 @@
+module MonadTrans where
+
+class MonadTrans t where
+    -- | Lift a computation from
+    -- the argument monad to
+    -- the constructed monad.
+    lift :: (Monad m) => m a -> t m a
diff --git a/Haskell-book/26/MaybeT/src/Reader.hs b/Haskell-book/26/MaybeT/src/Reader.hs
new file mode 100644
index 0000000..38fded9
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/Reader.hs
@@ -0,0 +1,35 @@
+module Reader where
+
+import MonadIO
+import MonadTrans
+
+newtype ReaderT r m a =
+    ReaderT { runReaderT :: r -> m a }
+
+instance (Functor m)
+      => Functor (ReaderT r m) where
+    fmap f (ReaderT rma) =
+        ReaderT $ (fmap . fmap) f rma
+
+instance (Applicative m)
+      => Applicative (ReaderT r m) where
+    pure a = ReaderT (pure (pure a))
+
+    (ReaderT fmab) <*> (ReaderT rma) =
+        ReaderT $ (<*>) <$> fmab <*> rma
+
+instance (Monad m)
+      => Monad (ReaderT r m) where
+    return = pure
+
+    (ReaderT rma) >>= f =
+        ReaderT $ \r -> do
+            a <- rma r
+            runReaderT (f a) r
+
+instance MonadTrans (ReaderT r) where
+    lift = ReaderT . const
+
+instance (MonadIO m)
+  => MonadIO (ReaderT r m) where
+      liftIO = lift . liftIO
diff --git a/Haskell-book/26/MaybeT/src/State.hs b/Haskell-book/26/MaybeT/src/State.hs
new file mode 100644
index 0000000..d30fdd5
--- /dev/null
+++ b/Haskell-book/26/MaybeT/src/State.hs
@@ -0,0 +1,41 @@
+module State where
+
+import MonadIO
+import MonadTrans
+
+newtype StateT s m a =
+    StateT { runStateT :: s -> m (a, s) }
+
+-- 1
+instance (Functor m)
+      => Functor (StateT s m) where
+    fmap f (StateT m) = StateT $ \s -> fmap first $ m s
+            where first = uncurry (\t1 t2 -> ((f t1), t2))
+            
+-- 2
+-- Links:
+--   http://stackoverflow.com/questions/18673525/is-it-possible-to-implement-applicative-m-applicative-statet-s-m
+--   https://github.com/NICTA/course/issues/134
+instance (Monad m)
+      => Applicative (StateT s m) where
+    pure x = StateT $ (\s -> pure (x, s))
+    StateT g <*> StateT h = StateT $ \s -> keepFirst <$> g s <*> h s
+        where keepFirst (f, s') (x, _) = (f x, s')
+  
+
+-- 3
+instance (Monad m)
+      => Monad (StateT s m) where
+    return = pure
+
+    (StateT sma) >>= f =
+        StateT $ \s -> do
+            a <- sma s
+            runStateT (f $ fst a) s
+
+instance MonadTrans (StateT s) where
+    lift c = StateT $ \s -> c >>= (\x -> return (x, s))
+
+instance (MonadIO m)
+  => MonadIO (StateT s m) where
+      liftIO = lift . liftIO
diff --git a/Haskell-book/26/MaybeT/stack.yaml b/Haskell-book/26/MaybeT/stack.yaml
new file mode 100644
index 0000000..05facc0
--- /dev/null
+++ b/Haskell-book/26/MaybeT/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-11.6
+
+# 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/26/MaybeT/test/Spec.hs b/Haskell-book/26/MaybeT/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/Haskell-book/26/MaybeT/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/Haskell-book/26/Morra/.gitignore b/Haskell-book/26/Morra/.gitignore
new file mode 100644
index 0000000..552029c
--- /dev/null
+++ b/Haskell-book/26/Morra/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Morra.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/26/Morra/Setup.hs b/Haskell-book/26/Morra/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/26/Morra/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/26/Morra/app/Main.hs b/Haskell-book/26/Morra/app/Main.hs
new file mode 100644
index 0000000..0b0d28a
--- /dev/null
+++ b/Haskell-book/26/Morra/app/Main.hs
@@ -0,0 +1,69 @@
+module Main where
+
+import Control.Monad
+import Control.Monad.Trans.State
+import System.Random
+import System.Console.ANSI (clearScreen)
+
+type Score = StateT (Integer, Integer) IO (Integer, Integer)
+
+yourTurn :: IO (Integer, Integer)
+yourTurn = do
+    putStrLn "Wie viele Finger zeigen Sie?"
+    shown <- liftM read getLine
+
+    putStrLn "Wie viele Finger wird der Gegner zeigen?"
+    guessed <- liftM read getLine
+
+    clearScreen
+
+    return (shown, guessed)
+
+
+aiTurn :: IO (Integer, Integer)
+aiTurn = do
+    gen1 <- getStdGen
+
+    let (shown, gen2) = randomR (1, 5) gen1
+    putStrLn $ "Der Gegner zeigt: " ++ (show shown)
+
+    let (guessed, gen3) = randomR (1, 5) gen2
+    putStrLn $ "Der Gegner hat " ++ (show guessed) ++ " geraten."
+
+    setStdGen gen3
+    return (shown, guessed)
+
+
+score :: IO (Integer, Integer) -> Score
+score partnerTurn = StateT $ \(s1, s2) -> do
+    you <- yourTurn
+    partner <- partnerTurn
+    let sum = (fst you) + (snd partner)
+
+    let yourScore = if (snd you) == sum then 1 else 0
+    let partnerScore = if (snd partner) == sum then 1 else 0
+    return ((yourScore, partnerScore), (s1 + yourScore, s2 + partnerScore))
+
+
+loopGame :: IO (Integer, Integer)
+         -> (Integer, Integer)
+         -> IO (Either (Integer, Integer) (Integer, Integer))
+loopGame partnerTurn currentScore = do
+    (result, s) <- runStateT (score partnerTurn) currentScore
+    putStrLn $ show $ result
+
+    case s of
+      (16, _) -> return $ Left result
+      (_, 16) -> return $ Right result
+      _       -> loopGame partnerTurn s
+
+
+main :: IO ()
+main = do
+    winner <- loopGame aiTurn (0, 0)
+
+    case winner of
+      Left x ->  putStrLn $ "You've won! Score: " ++ (show x)
+      Right x -> putStrLn $ "You've lost! Score: " ++ (show x)
+
+    return ()
diff --git a/Haskell-book/26/Morra/package.yaml b/Haskell-book/26/Morra/package.yaml
new file mode 100644
index 0000000..5b313af
--- /dev/null
+++ b/Haskell-book/26/Morra/package.yaml
@@ -0,0 +1,21 @@
+name:                Morra
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- random
+- transformers
+- ansi-terminal
+
+executables:
+  morra:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
diff --git a/Haskell-book/26/Morra/stack.yaml b/Haskell-book/26/Morra/stack.yaml
new file mode 100644
index 0000000..8235b57
--- /dev/null
+++ b/Haskell-book/26/Morra/stack.yaml
@@ -0,0 +1,65 @@
+# 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
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-11.9
+
+# 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
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (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: ">=1.7"
+#
+# 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/27/BottomExpression.hs b/Haskell-book/27/BottomExpression.hs
new file mode 100644
index 0000000..0f0d71d
--- /dev/null
+++ b/Haskell-book/27/BottomExpression.hs
@@ -0,0 +1,7 @@
+{-# LANGUAGE Strict #-}
+module BottomExpression where
+
+!x = undefined
+y = "blah"
+main = do
+    print $ snd $ seq x (x, y)
diff --git a/Haskell-book/27/StrictList.hs b/Haskell-book/27/StrictList.hs
new file mode 100644
index 0000000..f75bb05
--- /dev/null
+++ b/Haskell-book/27/StrictList.hs
@@ -0,0 +1,20 @@
+{-# LANGUAGE Strict #-}
+
+module StrictList where
+
+data List a =
+    Nil
+  | Cons ~a ~(List a)
+  deriving (Show)
+
+take' n _ | n <= 0 = Nil
+take' _ Nil = Nil
+take' n (Cons x xs) = (Cons x (take' (n - 1) xs))
+
+map' _ Nil = Nil
+map' f (Cons x xs) = (Cons (f x) (map' f xs))
+
+repeat' x = xs where xs = (Cons x xs)
+
+main = do
+    print $ take' 10 $ map' (+1) (repeat' 1)
diff --git a/Haskell-book/28/Bench/.gitignore b/Haskell-book/28/Bench/.gitignore
new file mode 100644
index 0000000..84192e8
--- /dev/null
+++ b/Haskell-book/28/Bench/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+Bench.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/28/Bench/Setup.hs b/Haskell-book/28/Bench/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/28/Bench/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/28/Bench/app/Main.hs b/Haskell-book/28/Bench/app/Main.hs
new file mode 100644
index 0000000..c3c602f
--- /dev/null
+++ b/Haskell-book/28/Bench/app/Main.hs
@@ -0,0 +1,46 @@
+module Main where
+
+import Criterion.Main
+import qualified Data.Map as M
+import qualified Data.Set as S
+import qualified Data.Vector as V
+import qualified Data.Vector.Unboxed as U
+
+genList :: Int -> [(String, Int)]
+genList n = go n []
+    where go 0 xs = ("0", 0) : xs
+          go n' xs = go (n' - 1) ((show n', n') : xs)
+
+pairList :: [(String, Int)]
+pairList = genList 9001
+
+testMap :: M.Map String Int
+testMap = M.fromList pairList
+
+testSet :: S.Set String
+testSet = S.fromList $ fmap fst pairList
+
+slice :: Int -> Int -> [a] -> [a]
+slice from len xs = take len (drop from xs)
+
+boxed :: V.Vector Int
+boxed = V.fromList [1..1000]
+
+unboxed :: U.Vector Int
+unboxed = U.fromList [1..1000]
+
+main :: IO ()
+main = defaultMain
+    [ bench "slicing unboxed vector" $
+        whnf (U.head . U.slice 100 900) unboxed
+    , bench "slicing boxed vector" $
+        whnf (V.head . V.slice 100 900) boxed
+    , bench "lookup one thing, set" $
+        whnf (S.member "doesntExist") testSet
+    , bench "insert one thing, set" $
+        whnf (S.insert "doesntExist" ) S.empty
+    , bench "lookup one thing, map" $
+        whnf (M.lookup "doesntExist") testMap
+    , bench "insert one thing, map" $
+        whnf (M.insert ("doesntExist", 0)) M.empty
+    ]
diff --git a/Haskell-book/28/Bench/package.yaml b/Haskell-book/28/Bench/package.yaml
new file mode 100644
index 0000000..cdf6c5f
--- /dev/null
+++ b/Haskell-book/28/Bench/package.yaml
@@ -0,0 +1,21 @@
+name:                Bench
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- containers
+- criterion
+- vector
+
+executables:
+  bench:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
diff --git a/Haskell-book/28/Bench/stack.yaml b/Haskell-book/28/Bench/stack.yaml
new file mode 100644
index 0000000..8235b57
--- /dev/null
+++ b/Haskell-book/28/Bench/stack.yaml
@@ -0,0 +1,65 @@
+# 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
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-11.9
+
+# 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
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (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: ">=1.7"
+#
+# 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/28/DifferenceList/.gitignore b/Haskell-book/28/DifferenceList/.gitignore
new file mode 100644
index 0000000..8543bc3
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/.gitignore
@@ -0,0 +1,3 @@
+.stack-work/
+DifferenceList.cabal
+*~
\ No newline at end of file
diff --git a/Haskell-book/28/DifferenceList/Setup.hs b/Haskell-book/28/DifferenceList/Setup.hs
new file mode 100644
index 0000000..9a994af
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/Haskell-book/28/DifferenceList/app/Main.hs b/Haskell-book/28/DifferenceList/app/Main.hs
new file mode 100644
index 0000000..8ece171
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/app/Main.hs
@@ -0,0 +1,46 @@
+module Main where
+
+import Criterion.Main
+import Data.DList
+import qualified Data.Queue as Q
+import qualified Data.Sequence as S
+
+schlemiel :: Int -> [Int]
+schlemiel i = go i []
+    where go 0 xs = xs
+          go n xs = go (n - 1) ([n] ++ xs)
+
+constructDlist :: Int -> [Int]
+constructDlist i = toList $ go i empty
+    where go 0 xs = xs
+          go n xs = go (n - 1) (singleton n `append` xs)
+
+processQueue :: Int -> Q.Queue Int
+processQueue i = clear $ Q.pop $ fill i Q.empty
+    where fill 0 xs = xs
+          fill n xs = fill (n - 1) (Q.push n xs)
+          clear Nothing = Q.empty
+          clear (Just xs) = clear $ Q.pop $ snd xs
+
+processList :: Int -> [Int]
+processList i = go (schlemiel i)
+    where go [] = []
+          go (x:xs) = xs
+
+processSeq :: Int -> S.Seq Int
+processSeq i = go $ S.fromList $ schlemiel i
+    where go xs = if S.null xs then xs else go (S.deleteAt 0 xs)
+
+main :: IO ()
+main = defaultMain
+    [ bench "concat list" $
+      whnf schlemiel 123456
+    , bench "concat dlist" $
+      whnf constructDlist 123456
+    , bench "process queue" $
+      whnf processQueue 12345
+    , bench "process list" $
+      whnf processList 12345
+    , bench "process sequence" $
+      whnf processSeq 12345
+    ]
diff --git a/Haskell-book/28/DifferenceList/package.yaml b/Haskell-book/28/DifferenceList/package.yaml
new file mode 100644
index 0000000..654822a
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/package.yaml
@@ -0,0 +1,37 @@
+name:                DifferenceList
+version:             0.1.0.0
+license:             BSD3
+author:              "Eugen Wissner"
+maintainer:          "belka@caraus.de"
+copyright:           "2018 Eugen Wissner"
+
+dependencies:
+- base >= 4.7 && < 5
+- containers
+
+library:
+  source-dirs: src
+
+tests:
+  DifferenceList-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - DifferenceList
+    - hspec
+
+executables:
+  benchmark:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - DifferenceList
+    - criterion
diff --git a/Haskell-book/28/DifferenceList/src/Data/DList.hs b/Haskell-book/28/DifferenceList/src/Data/DList.hs
new file mode 100644
index 0000000..12d3a53
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/src/Data/DList.hs
@@ -0,0 +1,40 @@
+module Data.DList
+    ( DList(..)
+    , empty
+    , singleton
+    , toList
+    , cons
+    , snoc
+    , append
+    ) where
+
+newtype DList a = DL { unDL :: [a] -> [a] }
+
+empty :: DList a
+empty = DL ([] ++)
+{-# INLINE empty #-}
+
+singleton :: a -> DList a
+singleton x = DL ([x] ++)
+{-# INLINE singleton #-}
+
+toList :: DList a -> [a]
+toList xsf = unDL xsf []
+{-# INLINE toList #-}
+
+-- Prepend a single element to a dlist.
+infixr `cons`
+cons :: a -> DList a -> DList a
+cons x xs = DL ((x:) . unDL xs)
+{-# INLINE cons #-}
+
+-- Append a single element to a dlist.
+infixl `snoc`
+snoc :: DList a -> a -> DList a
+snoc xs x = append xs $ singleton x
+{-# INLINE snoc #-}
+
+-- Append dlists.
+append :: DList a -> DList a -> DList a
+append xsf ysf = DL $ (unDL xsf) . (unDL ysf)
+{-# INLINE append #-}
diff --git a/Haskell-book/28/DifferenceList/src/Data/Queue.hs b/Haskell-book/28/DifferenceList/src/Data/Queue.hs
new file mode 100644
index 0000000..68d1e1f
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/src/Data/Queue.hs
@@ -0,0 +1,44 @@
+module Data.Queue
+    ( Queue(..)
+    , empty
+    , isEmpty
+    , push
+    , pop
+    ) where
+
+-- From Okasaki's Purely Functional Data Structures
+data Queue a =
+    Queue { enqueue :: [a]
+          , dequeue :: [a]
+          } deriving (Eq, Show)
+
+isEmpty :: Queue a -> Bool
+isEmpty xs = length (enqueue xs) == 0
+          && length (dequeue xs) == 0
+
+empty :: Queue a
+empty = Queue [] []
+
+-- adds an item
+push :: a -> Queue a -> Queue a
+push x xs = Queue { enqueue = x : (enqueue xs)
+                  , dequeue = dequeue xs }
+
+pop :: Queue a -> Maybe (a, Queue a)
+pop xs = popFromLists (enqueue xs) (dequeue xs)
+    where popFromLists [] [] = Nothing
+          popFromLists en (d:de) = Just (d, Queue en de)
+          popFromLists en [] = popFromLists [] (reverse en)
+
+-- We’re going to give you less code this time, but your task is to
+-- implement the above and write a benchmark comparing it against
+-- performing alternating pushes and pops from a queue based on a
+-- single list. Alternating so that you can’t take advantage of reversing
+-- the list after a long series of pushes in order to perform a long series
+-- of pops efficiently.
+--
+-- Don’t forget to handle the case where the dequeue is empty and
+-- you need to shift items from the enqueue to the dequeue. You need
+-- to do so without violating “first come, first served”.
+-- Lastly, benchmark it against Sequence. Come up with a variety of
+-- tests. Add additional operations for your Queue type if you want.
diff --git a/Haskell-book/28/DifferenceList/stack.yaml b/Haskell-book/28/DifferenceList/stack.yaml
new file mode 100644
index 0000000..27a701e
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/stack.yaml
@@ -0,0 +1,65 @@
+# 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
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-11.10
+
+# 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
+#  subdirs:
+#  - auto-update
+#  - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# using the same syntax as the packages field.
+# (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: ">=1.7"
+#
+# 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/28/DifferenceList/test/Spec.hs b/Haskell-book/28/DifferenceList/test/Spec.hs
new file mode 100644
index 0000000..84d9376
--- /dev/null
+++ b/Haskell-book/28/DifferenceList/test/Spec.hs
@@ -0,0 +1,33 @@
+module Main where
+
+import Test.Hspec
+import Data.Queue
+
+main :: IO ()
+main = hspec $ do
+    describe "empty" $ do
+        it "returns an empty queue" $ do
+            (empty :: Queue Int) `shouldBe` (Queue [] [])
+
+    describe "push" $ do
+        it "puts an element into an empty queue" $ do
+            (push 5 empty) `shouldBe` (Queue [5] [])
+
+    describe "pop" $ do
+        it "takes the only element from the queue" $ do
+            (pop (Queue [5] [])) `shouldBe` (Just (5, Queue [] []))
+        it "returns nothing if the queue is empty" $ do
+            (pop ((Queue [] [])::Queue Int)) `shouldBe` Nothing
+        it "takes elements in the FIFO order" $ do
+            let queue = push 3 (push 5 empty)
+             in pop queue `shouldBe` Just (5, Queue [] [3])
+
+    describe "isEmpty" $ do
+        it "tells when the queue is empty" $ do
+            (isEmpty (empty :: Queue Int)) `shouldBe` True
+        it "tells when the enqueue part isn't empty" $ do
+            let queue = push 3 empty
+             in isEmpty queue `shouldBe` False
+        it "tells when the dequeue part isn't empty" $ do
+            let queue = fmap snd (pop $ push 3 (push 5 empty))
+             in fmap isEmpty queue `shouldBe` Just False
diff --git a/README.md b/README.md
index 2af94b1..73161bb 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,12 @@
+This repository contains solutions to excercises I have done
+working on some computer books.
+
+This README lists only the books and courses. Book subdirectory
+may contain an additional README.
+
 ## pharo-mooc
 
-This repository contains some excercises and projects from
-"[The Pharo Mooc](https://mooc.pharo.org/)".
+[The Pharo Mooc](https://mooc.pharo.org/).
 
 ## Java-Kompendium. Professionell Java programmieren lernen