Add Dnd-Character exercise (#548)

config.json

@@ -691,6 +691,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 9
+      },
+      {
+        "slug": "dnd-character",
+        "name": "D&D Character",
+        "uuid": "ff18c49d-46f2-4673-bb24-2bae04b87252",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
       }
     ]
   },

exercises/practice/dnd-character/.docs/instructions.md

@@ -0,0 +1,32 @@
+# Instructions
+
+For a game of [Dungeons & Dragons][dnd], each player starts by generating a character they can play with.
+This character has, among other things, six abilities; strength, dexterity, constitution, intelligence, wisdom and charisma.
+These six abilities have scores that are determined randomly.
+You do this by rolling four 6-sided dice and recording the sum of the largest three dice.
+You do this six times, once for each ability.
+
+Your character's initial hitpoints are 10 + your character's constitution modifier.
+You find your character's constitution modifier by subtracting 10 from your character's constitution, divide by 2 and round down.
+
+Write a random character generator that follows the above rules.
+
+For example, the six throws of four dice may look like:
+
+- 5, 3, 1, 6: You discard the 1 and sum 5 + 3 + 6 = 14, which you assign to strength.
+- 3, 2, 5, 3: You discard the 2 and sum 3 + 5 + 3 = 11, which you assign to dexterity.
+- 1, 1, 1, 1: You discard the 1 and sum 1 + 1 + 1 = 3, which you assign to constitution.
+- 2, 1, 6, 6: You discard the 1 and sum 2 + 6 + 6 = 14, which you assign to intelligence.
+- 3, 5, 3, 4: You discard the 3 and sum 5 + 3 + 4 = 12, which you assign to wisdom.
+- 6, 6, 6, 6: You discard the 6 and sum 6 + 6 + 6 = 18, which you assign to charisma.
+
+Because constitution is 3, the constitution modifier is -4 and the hitpoints are 6.
+
+~~~~exercism/note
+Most programming languages feature (pseudo-)random generators, but few programming languages are designed to roll dice.
+One such language is [Troll][troll].
+
+[troll]: https://di.ku.dk/Ansatte/?pure=da%2Fpublications%2Ftroll-a-language-for-specifying-dicerolls(84a45ff0-068b-11df-825d-000ea68e967b)%2Fexport.html
+~~~~
+
+[dnd]: https://en.wikipedia.org/wiki/Dungeons_%26_Dragons

exercises/practice/dnd-character/.docs/introduction.md

@@ -0,0 +1,10 @@
+# Introduction
+
+After weeks of anticipation, you and your friends get together for your very first game of [Dungeons & Dragons][dnd] (D&D).
+Since this is the first session of the game, each player has to generate a character to play with.
+The character's abilities are determined by rolling 6-sided dice, but where _are_ the dice?
+With a shock, you realize that your friends are waiting for _you_ to produce the dice; after all it was your idea to play D&D!
+Panicking, you realize you forgot to bring the dice, which would mean no D&D game.
+As you have some basic coding skills, you quickly come up with a solution: you'll write a program to simulate dice rolls.
+
+[dnd]: https://en.wikipedia.org/wiki/Dungeons_%26_Dragons

exercises/practice/dnd-character/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "glennj"
+  ],
+  "files": {
+    "solution": [
+      "lib/dnd_character.dart"
+    ],
+    "test": [
+      "test/dnd_character_test.dart"
+    ],
+    "example": [
+      ".meta/lib/example.dart"
+    ]
+  },
+  "blurb": "Randomly generate Dungeons & Dragons characters.",
+  "source": "Simon Shine, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/616#issuecomment-437358945"
+}

exercises/practice/dnd-character/.meta/lib/example.dart

@@ -0,0 +1,32 @@
+import 'dart:math';
+
+class DndCharacter {
+  static int modifier(int value) {
+    return ((value - 10) / 2).floor();
+  }
+
+  static int ability() {
+    final d6 = () => 1 + Random().nextInt(6);
+    final rolls = [d6(), d6(), d6(), d6()];
+    final total = rolls.fold(0, (s, roll) => s + roll);
+    final least = rolls.fold(7, (m, roll) => min(m, roll));
+    return total - least;
+  }
+
+  final int strength;
+  final int dexterity;
+  final int constitution;
+  final int intelligence;
+  final int wisdom;
+  final int charisma;
+  final int hitpoints;
+
+  DndCharacter(this.strength, this.dexterity, this.constitution,
+      this.intelligence, this.wisdom, this.charisma, this.hitpoints);
+
+  factory DndCharacter.create() {
+    final constitution = ability();
+    return DndCharacter(ability(), ability(), constitution, ability(),
+        ability(), ability(), 10 + modifier(constitution));
+  }
+}

exercises/practice/dnd-character/.meta/tests.toml

@@ -0,0 +1,72 @@
+# 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.
+
+[1e9ae1dc-35bd-43ba-aa08-e4b94c20fa37]
+description = "ability modifier -> ability modifier for score 3 is -4"
+
+[cc9bb24e-56b8-4e9e-989d-a0d1a29ebb9c]
+description = "ability modifier -> ability modifier for score 4 is -3"
+
+[5b519fcd-6946-41ee-91fe-34b4f9808326]
+description = "ability modifier -> ability modifier for score 5 is -3"
+
+[dc2913bd-6d7a-402e-b1e2-6d568b1cbe21]
+description = "ability modifier -> ability modifier for score 6 is -2"
+
+[099440f5-0d66-4b1a-8a10-8f3a03cc499f]
+description = "ability modifier -> ability modifier for score 7 is -2"
+
+[cfda6e5c-3489-42f0-b22b-4acb47084df0]
+description = "ability modifier -> ability modifier for score 8 is -1"
+
+[c70f0507-fa7e-4228-8463-858bfbba1754]
+description = "ability modifier -> ability modifier for score 9 is -1"
+
+[6f4e6c88-1cd9-46a0-92b8-db4a99b372f7]
+description = "ability modifier -> ability modifier for score 10 is 0"
+
+[e00d9e5c-63c8-413f-879d-cd9be9697097]
+description = "ability modifier -> ability modifier for score 11 is 0"
+
+[eea06f3c-8de0-45e7-9d9d-b8cab4179715]
+description = "ability modifier -> ability modifier for score 12 is +1"
+
+[9c51f6be-db72-4af7-92ac-b293a02c0dcd]
+description = "ability modifier -> ability modifier for score 13 is +1"
+
+[94053a5d-53b6-4efc-b669-a8b5098f7762]
+description = "ability modifier -> ability modifier for score 14 is +2"
+
+[8c33e7ca-3f9f-4820-8ab3-65f2c9e2f0e2]
+description = "ability modifier -> ability modifier for score 15 is +2"
+
+[c3ec871e-1791-44d0-b3cc-77e5fb4cd33d]
+description = "ability modifier -> ability modifier for score 16 is +3"
+
+[3d053cee-2888-4616-b9fd-602a3b1efff4]
+description = "ability modifier -> ability modifier for score 17 is +3"
+
+[bafd997a-e852-4e56-9f65-14b60261faee]
+description = "ability modifier -> ability modifier for score 18 is +4"
+
+[4f28f19c-2e47-4453-a46a-c0d365259c14]
+description = "random ability is within range"
+
+[385d7e72-864f-4e88-8279-81a7d75b04ad]
+description = "random character is valid"
+
+[2ca77b9b-c099-46c3-a02c-0d0f68ffa0fe]
+description = "each ability is only calculated once"
+include = false
+
+[dca2b2ec-f729-4551-84b9-078876bb4808]
+description = "each ability is only calculated once"
+reimplements = "2ca77b9b-c099-46c3-a02c-0d0f68ffa0fe"

exercises/practice/dnd-character/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/dnd-character/lib/dnd_character.dart

@@ -0,0 +1,3 @@
+class DndCharacter {
+  // Put your code here
+}

exercises/practice/dnd-character/pubspec.yaml

@@ -0,0 +1,5 @@
+name: 'dnd_character'
+environment:
+  sdk: '>=3.2.0 <4.0.0'
+dev_dependencies:
+  test: '<2.0.0'

exercises/practice/dnd-character/test/dnd_character_test.dart

@@ -0,0 +1,120 @@
+import 'package:dnd_character/dnd_character.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('DndCharacter: ability modifier - ', abilityModifier);
+  group('DndCharacter: abilities - ', abilities);
+}
+
+void abilityModifier() {
+  test('ability modifier for score 3 is -4', () {
+    expect(DndCharacter.modifier(3), equals(-4));
+  }, skip: false);
+
+  test('ability modifier for score 4 is -3', () {
+    expect(DndCharacter.modifier(4), equals(-3));
+  }, skip: true);
+
+  test('ability modifier for score 5 is -3', () {
+    expect(DndCharacter.modifier(5), equals(-3));
+  }, skip: true);
+
+  test('ability modifier for score 6 is -2', () {
+    expect(DndCharacter.modifier(6), equals(-2));
+  }, skip: true);
+
+  test('ability modifier for score 7 is -2', () {
+    expect(DndCharacter.modifier(7), equals(-2));
+  }, skip: true);
+
+  test('ability modifier for score 8 is -1', () {
+    expect(DndCharacter.modifier(8), equals(-1));
+  }, skip: true);
+
+  test('ability modifier for score 9 is -1', () {
+    expect(DndCharacter.modifier(9), equals(-1));
+  }, skip: true);
+
+  test('ability modifier for score 10 is 0', () {
+    expect(DndCharacter.modifier(10), equals(0));
+  }, skip: true);
+
+  test('ability modifier for score 11 is 0', () {
+    expect(DndCharacter.modifier(11), equals(0));
+  }, skip: true);
+
+  test('ability modifier for score 12 is +1', () {
+    expect(DndCharacter.modifier(12), equals(1));
+  }, skip: true);
+
+  test('ability modifier for score 13 is +1', () {
+    expect(DndCharacter.modifier(13), equals(1));
+  }, skip: true);
+
+  test('ability modifier for score 14 is +2', () {
+    expect(DndCharacter.modifier(14), equals(2));
+  }, skip: true);
+
+  test('ability modifier for score 15 is +2', () {
+    expect(DndCharacter.modifier(15), equals(2));
+  }, skip: true);
+
+  test('ability modifier for score 16 is +3', () {
+    expect(DndCharacter.modifier(16), equals(3));
+  }, skip: true);
+
+  test('ability modifier for score 17 is +3', () {
+    expect(DndCharacter.modifier(17), equals(3));
+  }, skip: true);
+
+  test('ability modifier for score 18 is +4', () {
+    final result = DndCharacter.modifier(18);
+    expect(result, equals(4));
+  }, skip: true);
+}
+
+void abilities() {
+  test('random ability is within range', () {
+    final score = DndCharacter.ability();
+    expect(score, inInclusiveRange(3, 18));
+  }, skip: true);
+
+  test('random character is valid', () {
+    final character = DndCharacter.create();
+    expect(character.strength, inInclusiveRange(3, 18));
+    expect(character.dexterity, inInclusiveRange(3, 18));
+    expect(character.constitution, inInclusiveRange(3, 18));
+    expect(character.intelligence, inInclusiveRange(3, 18));
+    expect(character.wisdom, inInclusiveRange(3, 18));
+    expect(character.charisma, inInclusiveRange(3, 18));
+    expect(character.hitpoints, equals(10 + DndCharacter.modifier(character.constitution)));
+  }, skip: true);
+
+  test('each ability is only calculated once', () {
+    final character = DndCharacter.create();
+
+    var read1 = character.strength;
+    var read2 = character.strength;
+    expect(read1, equals(read2));
+
+    read1 = character.dexterity;
+    read2 = character.dexterity;
+    expect(read1, equals(read2));
+
+    read1 = character.constitution;
+    read2 = character.constitution;
+    expect(read1, equals(read2));
+
+    read1 = character.intelligence;
+    read2 = character.intelligence;
+    expect(read1, equals(read2));
+
+    read1 = character.wisdom;
+    read2 = character.wisdom;
+    expect(read1, equals(read2));
+
+    read1 = character.charisma;
+    read2 = character.charisma;
+    expect(read1, equals(read2));
+  }, skip: true);
+}