Add remaining haskell book exercises

Haskell-book/25/Twinplicative/.gitignore

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+.stack-work/
+Twinplicative.cabal
+*~

Haskell-book/25/Twinplicative/LICENSE

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+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.

Haskell-book/25/Twinplicative/Setup.hs

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+import Distribution.Simple
+main = defaultMain

Haskell-book/25/Twinplicative/package.yaml

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+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

Haskell-book/25/Twinplicative/src/Twinplicative.hs

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+{-# 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

Haskell-book/25/Twinplicative/stack.yaml

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+# 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