initial commit

.gitignore

@@ -21,3 +21,5 @@ cabal.project.local
 cabal.project.local~
 .HTF/
 .ghc.environment.*
+*.cabal
+stack.yaml.lock

Setup.hs

@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain

app/Main.hs

@@ -0,0 +1,6 @@
+module Main where
+
+import Lib
+
+main :: IO ()
+main = someFunc

package.yaml

@@ -0,0 +1,48 @@
+name:                GentleIntroductionToHaskell
+version:             0.1.0.0
+github:              "githubuser/GentleIntroductionToHaskell"
+license:             Apache-2.0
+author:              "Thomas Mahler"
+maintainer:          "thma@apache.org"
+copyright:           "2020 Thomas Mahler"
+
+extra-source-files:
+- README.md
+
+# Metadata used when publishing your package
+# synopsis:            A gentle introduction to basic Haskell concepts
+# category:            Programming
+
+# To avoid duplicated efforts in documentation and dealing with the
+# complications of embedding Haddock markup inside cabal files, it is
+# common to point users to the README.md file.
+description:         Please see the README on GitHub at <https://github.com/thma/GentleIntroductionToHaskell#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+- natural-numbers
+
+library:
+  source-dirs: src
+
+executables:
+  GentleIntroductionToHaskell-exe:
+    main:                Main.hs
+    source-dirs:         app
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - GentleIntroductionToHaskell
+
+tests:
+  GentleIntroductionToHaskell-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - GentleIntroductionToHaskell

src/Functions.hs

@@ -0,0 +1,41 @@
+module Functions where
+
+import Data.Natural
+
+-- take an Int as argument and compute its square
+square :: Int -> Int
+square x = x * x
+
+-- take a tuple of two Ints and compute their product
+mul :: (Int, Int) -> Int
+mul (x, y) = x * y
+
+-- add two numbers 
+add :: Int -> Int -> Int
+add x y = x + y
+
+-- partial application: applying add to 5 returns a function of type Int -> Int
+add5 :: Int -> Int
+add5 = add 5
+
+-- The function curry takes a function of type ((a, b) -> c) and return the equivalent curried function of type a -> b -> c
+-- curry :: ((a, b) -> c) -> a -> b -> c
+curMul :: Int -> Int -> Int
+curMul = curry mul
+
+-- uncurry does the inverse, take the curried form and return the equivalent uncurried function
+-- uncurry :: (a -> b -> c) -> (a, b) -> c
+uncurAdd :: (Int, Int) -> Int
+uncurAdd = uncurry add
+
+-- recursive definition of factorial 
+factorial :: Natural -> Natural
+factorial n = 
+  if n == 0
+    then 1
+    else n * factorial (n - 1)
+
+-- definition of factorial using pattern matching
+fac :: Natural -> Natural
+fac 0 = 1
+fac n = n * fac (n - 1)

src/Lib.hs

@@ -0,0 +1,6 @@
+module Lib
+    ( someFunc
+    ) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"

stack.yaml

@@ -0,0 +1,67 @@
+# 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
+#
+# 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-14.23
+
+# 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
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+extra-deps:
+- natural-numbers-0.1.2.0@sha256:0fcbe1220979b83fa612fca73a1adb1a99ff43c84f9652b3ff32b2323309b43c,1407
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# 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: ">=2.2"
+#
+# 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

test/Spec.hs

@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"