Add Haskell port

haskell/.gitignore

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+*.hi
+*.ho
+TAGS
+*.log
+*.profile
+/dist
+/cabal.config
+
+/.cabal-sandbox/
+/cabal.sandbox.config
+

haskell/README.md

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+# Haskell port of the Gilded-Rose Kata
+
+This is a Haskell port of the *Gilded-Rose-Kata*. For updates and pull-request
+on this haskell port go to https://github.com/sheyll/gilded-rose-haskell
+
+## Building and Running
+
+Run `./install_deps.sh` initially, then `./test.sh` to execute the tests after
+each refactoring.
+
+To execute the program run `./run.sh [days]` where `[days]` denotes an optional
+parameter for the number of days to simulate.
+
+Tests are in `test/GildedRoseSpec.hs`. Refer to http://hspec.github.io/ for
+more information about writing tests using `Hspec`.

haskell/gilded-rose.cabal

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+name:                gilded-rose
+version:             0.1.0.0
+synopsis:            Haskell-port of the gilded rose kata
+license:             GPL
+author:              Sven Heyll
+maintainer:          sven.heyll@gmail.com
+category:            System
+build-type:          Simple
+cabal-version:       >=1.10
+
+library
+  exposed-modules:   GildedRose
+  build-depends:     base >=4.7 && <4.8
+  hs-source-dirs:    src
+  default-language:  Haskell2010
+
+executable gilded-rose
+  main-is:           Main.hs
+  build-depends:     gilded-rose, base >=4.7 && <4.8
+  hs-source-dirs:    src
+  default-language:  Haskell2010
+
+test-suite spec
+  type:              exitcode-stdio-1.0
+  ghc-options:       -Wall
+  hs-source-dirs:    test
+  default-language:  Haskell2010
+  main-is:           Spec.hs
+  other-modules:     GildedRoseSpec
+  build-depends:     base >=4.7 && <4.8
+                   , gilded-rose
+                   , hspec
+                   , hspec-expectations
+                   , QuickCheck

haskell/install_deps.sh

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+#!/bin/bash
+#
+# Fetch and build all dependencies
+#
+set -eu
+
+cabal install --enable-tests --disable-optimization --dependencies-only
+cabal -v0 configure --enable-tests --disable-optimization

haskell/run.sh

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+#!/bin/bash
+#
+# Rebuild the project and run Main.main with all arguments passed to this
+# script.
+#
+set -eu
+
+cabal -v0 run $@

haskell/src/GildedRose.hs

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+module GildedRose where
+
+type GildedRose = [Item]
+
+data Item = Item String Int Int
+  deriving (Eq)
+
+instance Show Item where
+  show (Item name sellIn quality) =
+    name ++ ", " ++ show sellIn ++ ", " ++ show quality
+
+updateQuality :: GildedRose -> GildedRose
+updateQuality = map updateQualityItem
+  where
+    updateQualityItem (Item name sellIn quality) =
+      let
+        quality' =
+          if name /= "Aged Brie"
+             && name /= "Backstage passes to a TAFKAL80ETC concert"
+          then
+            if quality > 0
+            then
+              if name /= "Sulfuras, Hand of Ragnaros"
+              then quality - 1
+              else quality
+            else quality
+          else
+            if quality < 50
+            then
+              quality + 1 +
+                (if name == "Backstage passes to a TAFKAL80ETC concert"
+                 then
+                   if sellIn < 11
+                   then
+                     if quality < 49
+                     then
+                       1 + (if sellIn < 6
+                            then
+                              if quality < 48
+                              then 1
+                              else 0
+                            else 0)
+                     else 0
+                   else 0
+                 else 0)
+            else quality
+
+        sellIn' =
+          if name /= "Sulfuras, Hand of Ragnaros"
+          then sellIn - 1
+          else sellIn
+      in
+        if sellIn' < 0
+        then
+          if name /= "Aged Brie"
+          then
+            if name /= "Backstage passes to a TAFKAL80ETC concert"
+            then
+              if quality' > 0
+              then
+                if name /= "Sulfuras, Hand of Ragnaros"
+                then (Item name sellIn' (quality' - 1))
+                else (Item name sellIn' quality')
+              else (Item name sellIn' quality')
+            else (Item name sellIn' (quality' - quality'))
+          else
+            if quality' < 50
+            then (Item name sellIn' (quality' + 1))
+            else (Item name sellIn' quality')
+        else (Item name sellIn' quality')

haskell/src/Main.hs

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+module Main where
+
+import System.Environment
+import GildedRose
+
+
+main :: IO ()
+main = do
+  putStrLn "OMGHAI!"
+
+  let inventoriesWithDay = inventories `zip` [0..]
+      inventories = iterate updateQuality initialInventory
+
+  numberOfDays <- daysFromArg
+  mapM_ printUpdate (take numberOfDays inventoriesWithDay)
+
+  where
+    printUpdate :: (GildedRose, Int) -> IO ()
+    printUpdate (items, day) = do
+      putStrLn ("-------- day " ++ show day ++ " --------")
+      putStrLn "name, sellIn, quality"
+      mapM_ (putStrLn . show) items
+      putStrLn ""
+
+    daysFromArg :: IO Int
+    daysFromArg = do
+      args <- getArgs
+      return $ if length args > 0
+                  then read (head args)
+                  else 20
+
+    initialInventory :: GildedRose
+    initialInventory =
+      [ Item "+5 Dexterity Vest"                          10  20
+      , Item "Aged Brie"                                   2   0
+      , Item "Elixir of the Mongoose"                      5   7
+      , Item "Sulfuras, Hand of Ragnaros"                  0  80
+      , Item "Sulfuras, Hand of Ragnaros"                (-1) 80
+      , Item "Backstage passes to a TAFKAL80ETC concert"  15  20
+      , Item "Backstage passes to a TAFKAL80ETC concert"  10  49
+      , Item "Backstage passes to a TAFKAL80ETC concert"   5  49
+      -- this conjured item does not work properly yet
+      , Item "Conjured Mana Cake"                          3   6
+      ]

haskell/test.sh

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+#!/bin/bash
+#
+# Rebuild the project and run the hspec based unit tests.  This could have been
+# achieved by 'cabal test' but then the output would not be as colorful.
+#
+set -eu
+
+cabal -v0 build
+./dist/build/spec/spec $@

haskell/test/GildedRoseSpec.hs

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+module GildedRoseSpec (spec) where
+
+import Test.Hspec
+import GildedRose
+
+spec :: Spec
+spec =
+  describe "updateQuality" $ do
+
+    it "fixme" $
+       let inventory = [Item "foo" 0 0]
+           actual = updateQuality inventory
+           expected = []
+       in actual `shouldBe` expected

haskell/test/Spec.hs

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+{-# OPTIONS_GHC -F -pgmF hspec-discover #-}