Merge pull request #142 from tgecho/grains-fork

Grains exercise

config.json

@@ -153,6 +153,11 @@
             "slug": "gigasecond",
             "difficulty": 1,
             "topics": []
+        },
+        {
+            "slug": "grains",
+            "difficulty": 1,
+            "topics": []
         }
     ],
     "deprecated": [],

exercises/grains/Grains.elm

@@ -0,0 +1,2 @@
+module Grains exposing (..)
+

exercises/grains/Grains.example.elm

@@ -0,0 +1,9 @@
+module Grains exposing (..)
+
+
+square : Int -> Maybe Int
+square n =
+    if n < 1 then
+        Nothing
+    else
+        Just <| 2 ^ (n - 1)

exercises/grains/elm-package.json

@@ -0,0 +1,14 @@
+{
+    "version": "3.0.0",
+    "summary": "Exercism problems in Elm.",
+    "repository": "https://github.com/exercism/xelm.git",
+    "license": "BSD3",
+    "source-directories": [
+        "."
+    ],
+    "exposed-modules": [],
+    "dependencies": {
+        "elm-lang/core": "5.0.0 <= v < 6.0.0"
+    },
+    "elm-version": "0.18.0 <= v < 0.19.0"
+}

exercises/grains/package.json

@@ -0,0 +1,13 @@
+{
+    "description": "Exercism/Elm",
+    "repository": "https://github.com/exercism/xelm.git",
+    "license": "MIT",
+    "scripts": {
+        "postinstall": "elm-package install -y",
+        "test": "elm-test"
+    },
+    "dependencies": {
+        "elm": "0.18.0",
+        "elm-test": "0.18.3"
+    }
+}

exercises/grains/tests/Tests.elm

@@ -0,0 +1,37 @@
+module Tests exposing (..)
+
+import Expect
+import Grains exposing (square)
+import Json.Encode exposing (Value)
+import Test exposing (..)
+
+
+tests : Test
+tests =
+    describe "Grains"
+        [ describe "square"
+            [ test "of 1" <|
+                \() -> Expect.equal (Just 1) (square 1)
+            , test "of 2" <|
+                \() -> Expect.equal (Just 2) (square 2)
+            , test "of 3" <|
+                \() -> Expect.equal (Just 4) (square 3)
+            , test "of 4" <|
+                \() -> Expect.equal (Just 8) (square 4)
+            , test "of 16" <|
+                \() -> Expect.equal (Just 32768) (square 16)
+            , test "of 32" <|
+                \() -> Expect.equal (Just 2147483648) (square 32)
+            , test "square 0 raises an exception" <|
+                \() -> Expect.equal Nothing (square 0)
+            , test "negative square raises an exception" <|
+                \() -> Expect.equal Nothing (square -1)
+              {-
+                 Where are the bigger test values?!? Because Javascript's numbers
+                 can't represent values higher than `Number.MAX_SAFE_INTEGER`
+                 (i.e. 9007199254740991), we chose to exclude these final values
+                 to avoid the weirdness. A bit more information can be found
+                 here: https://github.com/elm-lang/elm-compiler/issues/1246
+              -}
+            ]
+        ]

exercises/grains/tests/elm-package.json

@@ -0,0 +1,16 @@
+{
+    "version": "3.0.0",
+    "summary": "Exercism problems in Elm.",
+    "repository": "https://github.com/exercism/xelm.git",
+    "license": "BSD3",
+    "source-directories": [
+        ".",
+        ".."
+    ],
+    "exposed-modules": [],
+    "dependencies": {
+        "elm-lang/core": "5.0.0 <= v < 6.0.0",
+        "elm-community/elm-test": "4.0.0 <= v < 5.0.0"
+    },
+    "elm-version": "0.18.0 <= v < 0.19.0"
+}