From 03e419b6175600640181404d786b056817650da9 Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:42:17 +0200
Subject: [PATCH 1/7] make docs

---
 .../dnd-character/.docs/instructions.md       | 32 +++++++++++++++++++
 .../dnd-character/.docs/introduction.md       | 10 ++++++
 2 files changed, 42 insertions(+)
 create mode 100644 exercises/practice/dnd-character/.docs/instructions.md
 create mode 100644 exercises/practice/dnd-character/.docs/introduction.md

diff --git a/exercises/practice/dnd-character/.docs/instructions.md b/exercises/practice/dnd-character/.docs/instructions.md
new file mode 100644
index 00000000..e14e7949
--- /dev/null
+++ b/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
diff --git a/exercises/practice/dnd-character/.docs/introduction.md b/exercises/practice/dnd-character/.docs/introduction.md
new file mode 100644
index 00000000..5301f618
--- /dev/null
+++ b/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

From aad7c64a173bc7b73d45b48097d8582f3a2b8349 Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:42:33 +0200
Subject: [PATCH 2/7] make metadata

---
 .../practice/dnd-character/.meta/config.json  | 20 ++++++
 .../practice/dnd-character/.meta/example.erl  | 45 ++++++++++++
 .../practice/dnd-character/.meta/tests.toml   | 72 +++++++++++++++++++
 3 files changed, 137 insertions(+)
 create mode 100644 exercises/practice/dnd-character/.meta/config.json
 create mode 100644 exercises/practice/dnd-character/.meta/example.erl
 create mode 100644 exercises/practice/dnd-character/.meta/tests.toml

diff --git a/exercises/practice/dnd-character/.meta/config.json b/exercises/practice/dnd-character/.meta/config.json
new file mode 100644
index 00000000..c22662a3
--- /dev/null
+++ b/exercises/practice/dnd-character/.meta/config.json
@@ -0,0 +1,20 @@
+{
+  "authors": [""],
+  "contributors": [
+    "Maartz"
+  ],
+  "files": {
+    "solution": [
+      "src/dnd_character.erl"
+    ],
+    "test": [
+      "test/dnd_character_tests.erl"
+    ],
+    "example": [
+      ".meta/example.erl"
+    ]
+  },
+  "blurb": "Randomly generate Dungeons & Dragons characters.",
+  "source": "Simon Shine, Erik Schierboom",
+  "source_url": "https://github.com/exercism/problem-specifications/issues/616#issuecomment-437358945"
+}
diff --git a/exercises/practice/dnd-character/.meta/example.erl b/exercises/practice/dnd-character/.meta/example.erl
new file mode 100644
index 00000000..fa514520
--- /dev/null
+++ b/exercises/practice/dnd-character/.meta/example.erl
@@ -0,0 +1,45 @@
+-module(example).
+
+-export([modifier/1, ability/0, character/0]).
+
+-record(?MODULE, {
+    strength,
+    dexterity,
+    constitution,
+    intelligence,
+    wisdom,
+    charisma,
+    hitpoints
+}).
+
+-export_type([character/0]).
+-type character() :: #?MODULE{}.
+
+%% @doc Calculate the ability modifier for a given ability score
+-spec modifier(pos_integer()) -> integer().
+modifier(Score) ->
+    (Score - 10) div 2.
+
+%% @doc Generate a random ability score
+-spec ability() -> pos_integer().
+ability() ->
+    Rolls = [rand:uniform(6) || _ <- lists:seq(1, 4)],
+
+    SortedRolls = lists:sort(Rolls),
+    [_ | HighestThree] = SortedRolls,
+    lists:sum(HighestThree).
+
+%% @doc Generate a complete character with random ability scores
+-spec character() -> character().
+character() ->
+    Constitution = ability(),
+
+    #?MODULE{
+        strength = ability(),
+        dexterity = ability(),
+        constitution = Constitution,
+        intelligence = ability(),
+        wisdom = ability(),
+        charisma = ability(),
+        hitpoints = 10 + modifier(Constitution)
+    }.
diff --git a/exercises/practice/dnd-character/.meta/tests.toml b/exercises/practice/dnd-character/.meta/tests.toml
new file mode 100644
index 00000000..719043b2
--- /dev/null
+++ b/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"

From 19e950c119df7844ab5f2a1e7a3e81b94a87828f Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:42:41 +0200
Subject: [PATCH 3/7] update global conf

---
 config.json | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/config.json b/config.json
index 3175db29..ad1b4fc9 100644
--- a/config.json
+++ b/config.json
@@ -1021,6 +1021,14 @@
         "practices": [],
         "prerequisites": [],
         "difficulty": 5
+      },
+      {
+        "slug": "dnd-character",
+        "name": "D&D Character",
+        "uuid": "4fc39dbe-4515-40d6-a59a-2098887b2a76",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1
       }
     ],
     "foregone": [

From 421b96c4340cd7698449078287b47bdfdf265cab Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:42:46 +0200
Subject: [PATCH 4/7] make the tests

---
 .../test/dnd_character_tests.erl              | 107 ++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 exercises/practice/dnd-character/test/dnd_character_tests.erl

diff --git a/exercises/practice/dnd-character/test/dnd_character_tests.erl b/exercises/practice/dnd-character/test/dnd_character_tests.erl
new file mode 100644
index 00000000..c1fefeff
--- /dev/null
+++ b/exercises/practice/dnd-character/test/dnd_character_tests.erl
@@ -0,0 +1,107 @@
+-module(dnd_character_tests).
+
+-include_lib("erl_exercism/include/exercism.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+%% Ability modifier tests
+
+'1_ability_modifier_for_score_3_is_minus_4_test_'() ->
+    {"ability modifier for score 3 is -4",
+     ?_assertEqual(-4, dnd_character:modifier(3))}.
+
+'2_ability_modifier_for_score_4_is_minus_3_test_'() ->
+    {"ability modifier for score 4 is -3",
+     ?_assertEqual(-3, dnd_character:modifier(4))}.
+
+'3_ability_modifier_for_score_5_is_minus_3_test_'() ->
+    {"ability modifier for score 5 is -3",
+     ?_assertEqual(-3, dnd_character:modifier(5))}.
+
+'4_ability_modifier_for_score_6_is_minus_2_test_'() ->
+    {"ability modifier for score 6 is -2",
+     ?_assertEqual(-2, dnd_character:modifier(6))}.
+
+'5_ability_modifier_for_score_7_is_minus_2_test_'() ->
+    {"ability modifier for score 7 is -2",
+     ?_assertEqual(-2, dnd_character:modifier(7))}.
+
+'6_ability_modifier_for_score_8_is_minus_1_test_'() ->
+    {"ability modifier for score 8 is -1",
+     ?_assertEqual(-1, dnd_character:modifier(8))}.
+
+'7_ability_modifier_for_score_9_is_minus_1_test_'() ->
+    {"ability modifier for score 9 is -1",
+     ?_assertEqual(-1, dnd_character:modifier(9))}.
+
+'8_ability_modifier_for_score_10_is_0_test_'() ->
+    {"ability modifier for score 10 is 0",
+     ?_assertEqual(0, dnd_character:modifier(10))}.
+
+'9_ability_modifier_for_score_11_is_0_test_'() ->
+    {"ability modifier for score 11 is 0",
+     ?_assertEqual(0, dnd_character:modifier(11))}.
+
+'10_ability_modifier_for_score_12_is_plus_1_test_'() ->
+    {"ability modifier for score 12 is +1",
+     ?_assertEqual(1, dnd_character:modifier(12))}.
+
+'11_ability_modifier_for_score_13_is_plus_1_test_'() ->
+    {"ability modifier for score 13 is +1",
+     ?_assertEqual(1, dnd_character:modifier(13))}.
+
+'12_ability_modifier_for_score_14_is_plus_2_test_'() ->
+    {"ability modifier for score 14 is +2",
+     ?_assertEqual(2, dnd_character:modifier(14))}.
+
+'13_ability_modifier_for_score_15_is_plus_2_test_'() ->
+    {"ability modifier for score 15 is +2",
+     ?_assertEqual(2, dnd_character:modifier(15))}.
+
+'14_ability_modifier_for_score_16_is_plus_3_test_'() ->
+    {"ability modifier for score 16 is +3",
+     ?_assertEqual(3, dnd_character:modifier(16))}.
+
+'15_ability_modifier_for_score_17_is_plus_3_test_'() ->
+    {"ability modifier for score 17 is +3",
+     ?_assertEqual(3, dnd_character:modifier(17))}.
+
+'16_ability_modifier_for_score_18_is_plus_4_test_'() ->
+    {"ability modifier for score 18 is +4",
+     ?_assertEqual(4, dnd_character:modifier(18))}.
+
+%% Random ability tests
+
+'17_random_ability_is_within_range_test_'() ->
+    {"random ability is within range",
+     fun() ->
+        Results = [dnd_character:ability() || _ <- lists:seq(1, 200)],
+        [?assert(Result >= 3 andalso Result =< 18) || Result <- Results],
+        ok
+     end}.
+
+%% Random character tests
+
+'18_random_character_has_valid_values_test_'() ->
+    {"random character has each ability within range and valid hitpoints",
+     fun() ->
+        Characters = [dnd_character:character() || _ <- lists:seq(1, 20)],
+
+        lists:foreach(fun(Character) ->
+            #{strength := Strength,
+              dexterity := Dexterity,
+              constitution := Constitution,
+              intelligence := Intelligence,
+              wisdom := Wisdom,
+              charisma := Charisma,
+              hitpoints := Hitpoints} = Character,
+
+            ?assert(Strength >= 3 andalso Strength =< 18),
+            ?assert(Dexterity >= 3 andalso Dexterity =< 18),
+            ?assert(Constitution >= 3 andalso Constitution =< 18),
+            ?assert(Intelligence >= 3 andalso Intelligence =< 18),
+            ?assert(Wisdom >= 3 andalso Wisdom =< 18),
+            ?assert(Charisma >= 3 andalso Charisma =< 18),
+            ?assertEqual(10 + dnd_character:modifier(Constitution), Hitpoints)
+        end, Characters),
+        ok
+     end}.

From d0b115e7e3695bf132de5b8b1c86555c688a5433 Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:44:44 +0200
Subject: [PATCH 5/7] stub

---
 exercises/practice/dnd-character/src/dnd_character.erl | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 exercises/practice/dnd-character/src/dnd_character.erl

diff --git a/exercises/practice/dnd-character/src/dnd_character.erl b/exercises/practice/dnd-character/src/dnd_character.erl
new file mode 100644
index 00000000..7f3d246e
--- /dev/null
+++ b/exercises/practice/dnd-character/src/dnd_character.erl
@@ -0,0 +1 @@
+-module(dnd_character).

From d5d03ee1bf1aaecc06fc2a3a072fd4035cb7645c Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 20:50:05 +0200
Subject: [PATCH 6/7] configlet lint of course

---
 exercises/practice/dnd-character/.meta/config.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/exercises/practice/dnd-character/.meta/config.json b/exercises/practice/dnd-character/.meta/config.json
index c22662a3..9b896bcd 100644
--- a/exercises/practice/dnd-character/.meta/config.json
+++ b/exercises/practice/dnd-character/.meta/config.json
@@ -1,5 +1,5 @@
 {
-  "authors": [""],
+  "authors": [],
   "contributors": [
     "Maartz"
   ],

From 6b8f24ec2b89f1938a7b7a3e559a35e42ba09580 Mon Sep 17 00:00:00 2001
From: Maartz <maartz@protonmail.com>
Date: Tue, 1 Apr 2025 21:15:08 +0200
Subject: [PATCH 7/7] switch from record to map

---
 .../practice/dnd-character/.meta/example.erl  | 41 +++++++------------
 .../test/dnd_character_tests.erl              | 11 +++--
 2 files changed, 22 insertions(+), 30 deletions(-)

diff --git a/exercises/practice/dnd-character/.meta/example.erl b/exercises/practice/dnd-character/.meta/example.erl
index fa514520..4a142570 100644
--- a/exercises/practice/dnd-character/.meta/example.erl
+++ b/exercises/practice/dnd-character/.meta/example.erl
@@ -1,45 +1,34 @@
 -module(example).
-
 -export([modifier/1, ability/0, character/0]).
 
--record(?MODULE, {
-    strength,
-    dexterity,
-    constitution,
-    intelligence,
-    wisdom,
-    charisma,
-    hitpoints
-}).
-
--export_type([character/0]).
--type character() :: #?MODULE{}.
-
 %% @doc Calculate the ability modifier for a given ability score
 -spec modifier(pos_integer()) -> integer().
 modifier(Score) ->
-    (Score - 10) div 2.
+    Diff = Score - 10,
+    case Diff < 0 andalso Diff rem 2 /= 0 of
+        true -> (Diff div 2) - 1;
+        false -> Diff div 2
+    end.
 
 %% @doc Generate a random ability score
 -spec ability() -> pos_integer().
 ability() ->
     Rolls = [rand:uniform(6) || _ <- lists:seq(1, 4)],
-
     SortedRolls = lists:sort(Rolls),
     [_ | HighestThree] = SortedRolls,
     lists:sum(HighestThree).
 
 %% @doc Generate a complete character with random ability scores
--spec character() -> character().
+-spec character() -> map().
 character() ->
     Constitution = ability(),
-
-    #?MODULE{
-        strength = ability(),
-        dexterity = ability(),
-        constitution = Constitution,
-        intelligence = ability(),
-        wisdom = ability(),
-        charisma = ability(),
-        hitpoints = 10 + modifier(Constitution)
+    #{
+        strength => ability(),
+        dexterity => ability(),
+        constitution => Constitution,
+        intelligence => ability(),
+        wisdom => ability(),
+        charisma => ability(),
+        hitpoints => 10 + modifier(Constitution)
     }.
+
diff --git a/exercises/practice/dnd-character/test/dnd_character_tests.erl b/exercises/practice/dnd-character/test/dnd_character_tests.erl
index c1fefeff..1df03dd0 100644
--- a/exercises/practice/dnd-character/test/dnd_character_tests.erl
+++ b/exercises/practice/dnd-character/test/dnd_character_tests.erl
@@ -85,16 +85,18 @@
     {"random character has each ability within range and valid hitpoints",
      fun() ->
         Characters = [dnd_character:character() || _ <- lists:seq(1, 20)],
-
+        
         lists:foreach(fun(Character) ->
-            #{strength := Strength,
+            #{
+              strength := Strength,
               dexterity := Dexterity,
               constitution := Constitution,
               intelligence := Intelligence,
               wisdom := Wisdom,
               charisma := Charisma,
-              hitpoints := Hitpoints} = Character,
-
+              hitpoints := Hitpoints
+            } = Character,
+              
             ?assert(Strength >= 3 andalso Strength =< 18),
             ?assert(Dexterity >= 3 andalso Dexterity =< 18),
             ?assert(Constitution >= 3 andalso Constitution =< 18),
@@ -105,3 +107,4 @@
         end, Characters),
         ok
      end}.
+