New exercise: Roman Numerals

.gitignore

@@ -24,4 +24,4 @@ doc/
 
 ## IDE files/folders
 /.idea/
-/.vscode/
+/.vscode/

config.json

@@ -142,9 +142,9 @@
         ]
       },
       {
-        "uuid": "40dd01f4-71be-4b01-827c-fe6d8a33b32a",
         "slug": "high-scores",
         "name": "High Scores",
+        "uuid": "40dd01f4-71be-4b01-827c-fe6d8a33b32a",
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
@@ -179,7 +179,11 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 8,
-        "topics": ["domain_specific_languages", "parsing", "stacks"]
+        "topics": [
+          "domain_specific_languages",
+          "parsing",
+          "stacks"
+        ]
       },
       {
         "slug": "word-count",
@@ -263,9 +267,9 @@
         ]
       },
       {
-        "uuid": "6b552157-5c08-413e-8667-b9555a1dbba5",
         "slug": "sum-of-multiples",
         "name": "Sum of Multiples",
+        "uuid": "6b552157-5c08-413e-8667-b9555a1dbba5",
         "practices": [],
         "prerequisites": [],
         "difficulty": 2
@@ -622,7 +626,15 @@
           "arrays",
           "lists"
         ]
-      } 
+      },
+      {
+        "slug": "roman-numerals",
+        "name": "Roman Numerals",
+        "uuid": "8472c6f2-1ede-426e-8234-89b5da766d88",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      }
     ]
   },
   "concepts": [
@@ -669,50 +681,50 @@
   ],
   "key_features": [
     {
-      "icon": "web",
       "title": "Web and Mobile",
-      "content": "Dart has the Flutter library, which can be used to quickly build web and smartphone applications."
+      "content": "Dart has the Flutter library, which can be used to quickly build web and smartphone applications.",
+      "icon": "web"
     },
     {
-      "icon": "portable",
       "title": "iOS and Android",
-      "content": "Dart can be converted into Swift and Kotlin, making mobile development fast and efficient."
+      "content": "Dart can be converted into Swift and Kotlin, making mobile development fast and efficient.",
+      "icon": "portable"
     },
     {
-      "icon": "documentation",
       "title": "Full Documentation",
-      "content": "Dart's learning materials are constantly updated, making it easy to look up information."
+      "content": "Dart's learning materials are constantly updated, making it easy to look up information.",
+      "icon": "documentation"
     },
     {
-      "icon": "community",
       "title": "Countless Packages",
-      "content": "Easily build and publish packages for public use, which can be accessed from Dart directly."
+      "content": "Easily build and publish packages for public use, which can be accessed from Dart directly.",
+      "icon": "community"
     },
     {
-      "icon": "functional",
       "title": "Highly-organized Code",
-      "content": "Dart's coding style makes it easy to read and understand."
+      "content": "Dart's coding style makes it easy to read and understand.",
+      "icon": "functional"
     },
     {
-      "icon": "fun",
       "title": "Easy to Learn",
-      "content": "Dart is easy to understand and great for beginners to programming."
+      "content": "Dart is easy to understand and great for beginners to programming.",
+      "icon": "fun"
     }
   ],
   "tags": [
+    "execution_mode/compiled",
     "paradigm/declarative",
     "paradigm/functional",
     "paradigm/imperative",
     "paradigm/object_oriented",
-    "typing/static",
-    "typing/strong",
-    "execution_mode/compiled",
-    "platform/windows",
-    "platform/mac",
-    "platform/linux",
-    "platform/ios",
     "platform/android",
+    "platform/ios",
+    "platform/linux",
+    "platform/mac",
     "platform/web",
+    "platform/windows",
+    "typing/static",
+    "typing/strong",
     "used_for/cross_platform_development",
     "used_for/games",
     "used_for/guis",

exercises/practice/roman-numerals/.docs/instructions.append.md

@@ -0,0 +1,8 @@
+# ignore
+
+## Dart Extension Methods
+
+We're implementing this exercise with an extention method on the `int` class.
+For details, see [the Dart docs][extension-methods].
+
+[extension-methods]: https://dart.dev/language/extension-methods

exercises/practice/roman-numerals/.docs/instructions.md

@@ -0,0 +1,41 @@
+# Instructions
+
+Write a function to convert from normal numbers to Roman Numerals.
+
+The Romans were a clever bunch.
+They conquered most of Europe and ruled it for hundreds of years.
+They invented concrete and straight roads and even bikinis.
+One thing they never discovered though was the number zero.
+This made writing and dating extensive histories of their exploits slightly more challenging, but the system of numbers they came up with is still in use today.
+For example the BBC uses Roman numerals to date their programs.
+
+The Romans wrote numbers using letters - I, V, X, L, C, D, M.
+(notice these letters have lots of straight lines and are hence easy to hack into stone tablets).
+
+```text
+ 1  => I
+10  => X
+ 7  => VII
+```
+
+The maximum number supported by this notation is 3,999.
+(The Romans themselves didn't tend to go any higher)
+
+Wikipedia says: Modern Roman numerals ... are written by expressing each digit separately starting with the left most digit and skipping any digit with a value of zero.
+
+To see this in practice, consider the example of 1990.
+
+In Roman numerals 1990 is MCMXC:
+
+1000=M
+900=CM
+90=XC
+
+2008 is written as MMVIII:
+
+2000=MM
+8=VIII
+
+Learn more about [Roman numerals on Wikipedia][roman-numerals].
+
+[roman-numerals]: https://wiki.imperivm-romanvm.com/wiki/Roman_Numerals

exercises/practice/roman-numerals/.meta/config.json

@@ -0,0 +1,17 @@
+{
+  "authors": ["glennj"],
+  "files": {
+    "solution": [
+      "lib/roman_numerals.dart"
+    ],
+    "test": [
+      "test/roman_numerals_test.dart"
+    ],
+    "example": [
+      ".meta/lib/example.dart"
+    ]
+  },
+  "blurb": "Write a function to convert from normal numbers to Roman Numerals.",
+  "source": "The Roman Numeral Kata",
+  "source_url": "https://codingdojo.org/kata/RomanNumerals/"
+}

exercises/practice/roman-numerals/.meta/lib/example.dart

@@ -0,0 +1,22 @@
+extension ConvertToRomanNumerals on int {
+  String toRoman() {
+    var n = this;
+    var roman = '';
+    while (n > 0) {
+      if      (n >= 1000) { roman +=  'M'; n -= 1000; }
+      else if (n >=  900) { roman += 'CM'; n -=  900; }
+      else if (n >=  500) { roman +=  'D'; n -=  500; }
+      else if (n >=  400) { roman += 'CD'; n -=  400; }
+      else if (n >=  100) { roman +=  'C'; n -=  100; }
+      else if (n >=   90) { roman += 'XC'; n -=   90; }
+      else if (n >=   50) { roman +=  'L'; n -=   50; }
+      else if (n >=   40) { roman += 'XL'; n -=   40; }
+      else if (n >=   10) { roman +=  'X'; n -=   10; }
+      else if (n >=    9) { roman += 'IX'; n -=    9; }
+      else if (n >=    5) { roman +=  'V'; n -=    5; }
+      else if (n >=    4) { roman += 'IV'; n -=    4; }
+      else if (n >=    1) { roman +=  'I'; n -=    1; }
+    }
+    return roman;
+  }
+}

exercises/practice/roman-numerals/.meta/tests.toml

@@ -0,0 +1,88 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[19828a3a-fbf7-4661-8ddd-cbaeee0e2178]
+description = "1 is I"
+
+[f088f064-2d35-4476-9a41-f576da3f7b03]
+description = "2 is II"
+
+[b374a79c-3bea-43e6-8db8-1286f79c7106]
+description = "3 is III"
+
+[05a0a1d4-a140-4db1-82e8-fcc21fdb49bb]
+description = "4 is IV"
+
+[57c0f9ad-5024-46ab-975d-de18c430b290]
+description = "5 is V"
+
+[20a2b47f-e57f-4797-a541-0b3825d7f249]
+description = "6 is VI"
+
+[ff3fb08c-4917-4aab-9f4e-d663491d083d]
+description = "9 is IX"
+
+[6d1d82d5-bf3e-48af-9139-87d7165ed509]
+description = "16 is XVI"
+
+[2bda64ca-7d28-4c56-b08d-16ce65716cf6]
+description = "27 is XXVII"
+
+[a1f812ef-84da-4e02-b4f0-89c907d0962c]
+description = "48 is XLVIII"
+
+[607ead62-23d6-4c11-a396-ef821e2e5f75]
+description = "49 is XLIX"
+
+[d5b283d4-455d-4e68-aacf-add6c4b51915]
+description = "59 is LIX"
+
+[4465ffd5-34dc-44f3-ada5-56f5007b6dad]
+description = "66 is LXVI"
+
+[46b46e5b-24da-4180-bfe2-2ef30b39d0d0]
+description = "93 is XCIII"
+
+[30494be1-9afb-4f84-9d71-db9df18b55e3]
+description = "141 is CXLI"
+
+[267f0207-3c55-459a-b81d-67cec7a46ed9]
+description = "163 is CLXIII"
+
+[902ad132-0b4d-40e3-8597-ba5ed611dd8d]
+description = "166 is CLXVI"
+
+[cdb06885-4485-4d71-8bfb-c9d0f496b404]
+description = "402 is CDII"
+
+[6b71841d-13b2-46b4-ba97-dec28133ea80]
+description = "575 is DLXXV"
+
+[dacb84b9-ea1c-4a61-acbb-ce6b36674906]
+description = "666 is DCLXVI"
+
+[432de891-7fd6-4748-a7f6-156082eeca2f]
+description = "911 is CMXI"
+
+[e6de6d24-f668-41c0-88d7-889c0254d173]
+description = "1024 is MXXIV"
+
+[efbe1d6a-9f98-4eb5-82bc-72753e3ac328]
+description = "1666 is MDCLXVI"
+
+[bb550038-d4eb-4be2-a9ce-f21961ac3bc6]
+description = "3000 is MMM"
+
+[3bc4b41c-c2e6-49d9-9142-420691504336]
+description = "3001 is MMMI"
+
+[4e18e96b-5fbb-43df-a91b-9cb511fe0856]
+description = "3999 is MMMCMXCIX"

exercises/practice/roman-numerals/analysis_options.yaml

@@ -0,0 +1,18 @@
+analyzer:
+  strong-mode:
+    implicit-casts: false
+    implicit-dynamic: false
+  errors:
+    unused_element:        error
+    unused_import:         error
+    unused_local_variable: error
+    dead_code:             error
+
+linter:
+  rules:
+    # Error Rules
+    - avoid_relative_lib_imports
+    - avoid_types_as_parameter_names
+    - literal_only_boolean_expressions
+    - no_adjacent_strings_in_list
+    - valid_regexps

exercises/practice/roman-numerals/lib/roman_numerals.dart

@@ -0,0 +1,5 @@
+extension ConvertToRomanNumerals on int {
+  String toRoman() {
+    // Put your code here
+  }
+}

exercises/practice/roman-numerals/pubspec.yaml

@@ -0,0 +1,5 @@
+name: 'roman_numerals'
+environment:
+  sdk: '>=2.18.0 <3.0.0'
+dev_dependencies:
+  test: '<2.0.0'