Add hello-world exercise

config.json

@@ -4,6 +4,12 @@
   "repository": "https://github.com/exercism/xhaskell",
   "active": true,
   "exercises": [
+    {
+      "slug": "hello-world",
+      "difficulty": 1,
+      "topics": [
+      ]
+    },
     {
       "slug": "leap",
       "difficulty": 1,

exercises/hello-world/HINTS.md

@@ -0,0 +1,6 @@
+## Hints
+
+To complete this exercise, you need to implement the `hello` function.
+
+You will find the type signature for `hello` already in place,
+but it is up to you to define the function.

exercises/hello-world/examples/success-standard/package.yaml

@@ -0,0 +1,16 @@
+name: hello-world
+
+dependencies:
+  - base
+
+library:
+  exposed-modules: HelloWorld
+  source-dirs: src
+
+tests:
+  test:
+    main: Tests.hs
+    source-dirs: test
+    dependencies:
+      - hello-world
+      - hspec

exercises/hello-world/examples/success-standard/src/HelloWorld.hs

@@ -0,0 +1,4 @@
+module HelloWorld (hello) where
+
+hello :: String
+hello = "Hello, World!"

exercises/hello-world/package.yaml

@@ -0,0 +1,19 @@
+name: hello-world
+
+dependencies:
+  - base
+
+library:
+  exposed-modules: HelloWorld
+  source-dirs: src
+  dependencies:
+  # - foo       # List here the packages you
+  # - bar       # want to use in your solution.
+
+tests:
+  test:
+    main: Tests.hs
+    source-dirs: test
+    dependencies:
+      - hello-world
+      - hspec

exercises/hello-world/src/HelloWorld.hs

@@ -0,0 +1,4 @@
+module HelloWorld (hello) where
+
+hello :: String
+hello = error "You need to implement this function."

exercises/hello-world/stack.yaml

@@ -0,0 +1 @@
+resolver: lts-7.16

exercises/hello-world/test/Tests.hs

@@ -0,0 +1,13 @@
+import Test.Hspec        (Spec, describe, it, shouldBe)
+import Test.Hspec.Runner (configFastFail, defaultConfig, hspecWith)
+
+import HelloWorld (hello)
+
+main :: IO ()
+main = hspecWith defaultConfig {configFastFail = True} specs
+
+specs :: Spec
+specs = describe "hello-world" $
+
+    it "hello" $
+      hello `shouldBe` "Hello, World!"