Add series exercise

config.json

@@ -22,6 +22,7 @@
     "run-length-encoding",
     "sublist",
     "nucleotide-count",
+    "series",
     "phone-number",
     "grade-school"
   ],

elm-package.json

@@ -23,6 +23,7 @@
         "./exercises/strain",
         "./exercises/space-age",
         "./exercises/nucleotide-count",
+        "./exercises/series",
         "./exercises/phone-number",
         "./exercises/grade-school"
     ],

exercises/series/Series.elm

@@ -0,0 +1 @@
+module Series (..) where

exercises/series/Series.example

@@ -0,0 +1,33 @@
+module Series (..) where
+
+import String
+import List
+import Result
+
+
+slices : Int -> String -> Result String (List (List Int))
+slices size input =
+  if size < 1 then
+    Err ("Invalid size: " ++ toString size)
+  else
+    String.split "" input
+      |> List.map String.toInt
+      |> combine
+      |> Result.map (takeRuns size)
+
+
+takeRuns : Int -> List Int -> List (List Int)
+takeRuns size numbers =
+  let
+    candidate =
+      List.take size numbers
+  in
+    if List.length candidate < size || size < 1 then
+      []
+    else
+      candidate :: takeRuns size (List.drop 1 numbers)
+
+
+combine : List (Result x a) -> Result x (List a)
+combine =
+  List.foldr (Result.map2 (::)) (Ok [])

exercises/series/SeriesTests.elm

@@ -0,0 +1,66 @@
+module Main (..) where
+
+import Task
+import Console
+import ElmTest exposing (..)
+import Series exposing (slices)
+
+
+tests : Test
+tests =
+  suite
+    "Series"
+    [ test
+        "slices of one"
+        (assertEqual
+          (Ok [ [ 0 ], [ 1 ], [ 2 ], [ 3 ], [ 4 ] ])
+          (slices 1 "01234")
+        )
+    , test
+        "slices of two"
+        (assertEqual
+          (Ok [ [ 9, 7 ], [ 7, 8 ], [ 8, 6 ], [ 6, 7 ], [ 7, 5 ], [ 5, 6 ], [ 6, 4 ] ])
+          (slices 2 "97867564")
+        )
+    , test
+        "slices of three"
+        (assertEqual
+          (Ok [ [ 9, 7, 8 ], [ 7, 8, 6 ], [ 8, 6, 7 ], [ 6, 7, 5 ], [ 7, 5, 6 ], [ 5, 6, 4 ] ])
+          (slices 3 "97867564")
+        )
+    , test
+        "slices of four"
+        (assertEqual
+          (Ok [ [ 0, 1, 2, 3 ], [ 1, 2, 3, 4 ] ])
+          (slices 4 "01234")
+        )
+    , test
+        "slices of five"
+        (assertEqual
+          (Ok [ [ 0, 1, 2, 3, 4 ] ])
+          (slices 5 "01234")
+        )
+    , test
+        "overly long slice"
+        (assertEqual
+          (Ok [])
+          (slices 4 "012")
+        )
+    , test
+        "overly short slice"
+        (assertEqual
+          (Err ("Invalid size: 0"))
+          (slices 0 "01234")
+        )
+    , test
+        "input has non numbers"
+        (assertEqual
+          (Err "could not convert string 'a' to an Int")
+          (slices 2 "0123abc")
+        )
+    ]
+
+
+port runner : Signal (Task.Task x ())
+port runner =
+  Console.run (consoleRunner tests)

exercises/series/elm-package.json

@@ -0,0 +1,16 @@
+{
+    "version": "1.0.0",
+    "summary": "Exercism problems in Elm.",
+    "repository": "https://github.com/exercism/xelm.git",
+    "license": "BSD3",
+    "source-directories": [
+        "."
+    ],
+    "exposed-modules": [],
+    "dependencies": {
+        "deadfoxygrandpa/elm-test": "3.0.1 <= v < 4.0.0",
+        "elm-lang/core": "2.0.0 <= v < 4.0.0",
+        "laszlopandy/elm-console": "1.1.0 <= v < 2.0.0"
+    },
+    "elm-version": "0.15.0 <= v < 0.17.0"
+}