Merge pull request #90 from rebelwarrior/roman-numerals

adds roman-numerals exercise

config.json

@@ -30,7 +30,8 @@
     "list-ops",
     "atbash-cipher",
     "say",
-    "largest-series-product"
+    "largest-series-product",
+    "roman-numerals"
   ],
   "deprecated": [
 

elm-package.json

@@ -31,7 +31,8 @@
         "./exercises/list-ops",
         "./exercises/atbash-cipher",
         "./exercises/say",
-        "./exercises/largest-series-product"
+        "./exercises/largest-series-product",
+        "./exercises/roman-numerals"
     ],
     "exposed-modules": [],
     "dependencies": {

exercises/roman-numerals/RomanNumerals.elm

@@ -0,0 +1 @@
+module RomanNumerals exposing (toRoman)

exercises/roman-numerals/RomanNumerals.example

@@ -0,0 +1,46 @@
+module RomanNumerals exposing (toRoman)
+
+import Dict
+import Maybe
+
+
+toRoman : Int -> String
+toRoman number =
+  if number == 0 then
+    ""
+  else
+    let
+      part = largestFactor number
+      letter =
+        numerals
+        |> Dict.get part 
+        |> Maybe.withDefault ""
+    in
+      letter ++ (toRoman (number - part))
+
+largestFactor : Int -> Int
+largestFactor number =
+  numerals
+  |> Dict.keys
+  |> List.filter (\p -> p <= number)
+  |> List.reverse
+  |> List.head
+  |> Maybe.withDefault 0
+
+
+numerals : Dict.Dict Int String
+numerals = Dict.fromList [
+    (1000, "M"),
+    ( 900, "CM"),
+    ( 500, "D"),
+    ( 400, "CD"),
+    ( 100, "C"),
+    (  90, "XC"),
+    (  50, "L"),
+    (  40, "XL"),
+    (  10, "X"),
+    (   9, "IX"),
+    (   5, "V"),
+    (   4, "IV"),
+    (   1, "I")
+  ]

exercises/roman-numerals/RomanNumeralsTests.elm

@@ -0,0 +1,86 @@
+module Main exposing (..)
+
+import ElmTest exposing (..)
+import RomanNumerals exposing (toRoman)
+
+
+tests : Test
+tests =
+    suite "Roman Numerals"
+        [ test "1"
+            (assertEqual ("I")
+                (toRoman 1)
+            )
+        , test "2"
+            (assertEqual ("II")
+                (toRoman 2)
+            )
+        , test "3"
+            (assertEqual ("III")
+                (toRoman 3)
+            )
+        , test "4"
+            (assertEqual ("IV")
+                (toRoman 4)
+            )
+        , test "5"
+            (assertEqual ("V")
+                (toRoman 5)
+            )
+        , test "6"
+            (assertEqual ("VI")
+                (toRoman 6)
+            )
+        , test "9"
+            (assertEqual ("IX")
+                (toRoman 9)
+            )
+        , test "27"
+            (assertEqual ("XXVII")
+                (toRoman 27)
+            )
+        , test "48"
+            (assertEqual ("XLVIII")
+                (toRoman 48)
+            )
+        , test "59"
+            (assertEqual ("LIX")
+                (toRoman 59)
+            )
+        , test "93"
+            (assertEqual ("XCIII")
+                (toRoman 93)
+            )
+        , test "141"
+            (assertEqual ("CXLI")
+                (toRoman 141)
+            )
+        , test "163"
+            (assertEqual ("CLXIII")
+                (toRoman 163)
+            )
+        , test "402"
+            (assertEqual ("CDII")
+                (toRoman 402)
+            )
+        , test "575"
+            (assertEqual ("DLXXV")
+                (toRoman 575)
+            )
+        , test "911"
+            (assertEqual ("CMXI")
+                (toRoman 911)
+            )
+        , test "1024"
+            (assertEqual ("MXXIV")
+                (toRoman 1024)
+            )
+        , test "3000"
+            (assertEqual ("MMM")
+                (toRoman 3000)
+            )
+        ]
+
+main : Program Never
+main =
+    runSuite tests

exercises/roman-numerals/elm-package.json

@@ -0,0 +1,15 @@
+{
+    "version": "2.0.0",
+    "summary": "Exercism problems in Elm.",
+    "repository": "https://github.com/exercism/xelm.git",
+    "license": "BSD3",
+    "source-directories": [
+        "."
+    ],
+    "exposed-modules": [],
+    "dependencies": {
+        "elm-community/elm-test": "1.0.0 <= v < 2.0.0",
+        "elm-lang/core": "4.0.0 <= v < 5.0.0"
+    },
+    "elm-version": "0.17.0 <= v < 0.18.0"
+}

exercises/roman-numerals/runtests.bat

@@ -0,0 +1,4 @@
+@echo off
+for %%f in (*Tests.elm) do (
+  elm-make %%f --yes --output build.js && node build.js
+)

exercises/roman-numerals/runtests.sh

@@ -0,0 +1,2 @@
+#!/usr/bin/env bash
+elm-make *Tests.elm --yes --output build.js && node build.js