Feat: Add D&D Character exercise

config.json

@@ -316,6 +316,14 @@
           "strings"
         ]
       },
+      {
+        "slug": "dnd-character",
+        "name": "D&D Character",
+        "uuid": "8fabd26a-9a2a-4afa-bcff-b5a89db7e4c3",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 5
+      },
       {
         "slug": "prime-factors",
         "name": "Prime Factors",

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 +1,20 @@
+{
+  "authors": ["khalidbelk"],
+  "files": {
+    "solution": [
+      "dnd_character.ml"
+    ],
+    "test": [
+      "test.ml"
+    ],
+    "example": [
+      ".meta/example.ml"
+    ],
+    "editor": [
+      "dnd_character.mli"
+    ]
+  },
+  "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/example.ml

@@ -0,0 +1,37 @@
+type character = {
+  charisma : int;
+  constitution : int;
+  dexterity : int;
+  hitpoints : int;
+  intelligence : int;
+  strength : int;
+  wisdom : int;
+}
+
+let roll_dice ()  =
+  let results = List.init 4 (fun _ -> 1 + Random.int 6)
+  in results |> List.sort (compare) |> List.tl
+
+let ability () =
+  let dice_result = roll_dice () in
+  dice_result |> List.fold_left (+) 0
+
+let modifier ~score =
+  let res = (float_of_int(score) -. 10.0) /. 2.0 in
+  int_of_float(floor res)
+
+let generate_character () =
+  let cons = ability () in
+  let modifier_value = modifier ~score:cons in
+  let charisma = ability () in
+  let constitution = cons in
+  let dexterity = ability () in
+  let hitpoints = 10 + modifier_value in
+  let intelligence = ability () in
+  let strength = ability () in
+  let wisdom = ability () in
+  { charisma; constitution; dexterity; hitpoints; intelligence; strength; wisdom }
+
+
+(* Init random seed *)
+let () = Random.self_init ()

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/Makefile

@@ -0,0 +1,9 @@
+default: clean test
+
+test: 
+	dune runtest
+
+clean:
+	dune clean
+
+.PHONY: clean

exercises/practice/dnd-character/dnd_character.ml

@@ -0,0 +1,8 @@
+let ability () =
+  failwith "'ability' is missing"
+
+let modifier ~score =
+  failwith "'modifier' is missing"
+
+let generate_character () =
+  failwith "'generate_character' is missing"

exercises/practice/dnd-character/dnd_character.mli

@@ -0,0 +1,18 @@
+type character = {
+  charisma : int;
+  constitution : int;
+  dexterity : int;
+  hitpoints : int;
+  intelligence : int;
+  strength : int;
+  wisdom : int;
+}
+
+(* Gives the random ability score obtained by rolling four 6-sided dice *)
+val ability : unit -> int
+
+(* Given an ability score, returns the ability modifier *)
+val modifier : score:int -> int
+
+(* Creates a new character *)
+val generate_character : unit -> character

exercises/practice/dnd-character/dune

@@ -0,0 +1,16 @@
+(executable
+ (name test)
+ (libraries base ounit2))
+
+(alias
+  (name    runtest)
+  (deps    (:x test.exe))
+  (action  (run %{x})))
+
+(alias
+  (name    buildtest)
+  (deps    (:x test.exe)))
+
+(env
+  (dev
+    (flags (:standard -warn-error -A))))

exercises/practice/dnd-character/dune-project

@@ -0,0 +1 @@
+(lang dune 1.1)

exercises/practice/dnd-character/test.ml

@@ -0,0 +1,110 @@
+open OUnit2
+open Dnd_character
+
+let ae exp got _test_ctxt =
+  assert_equal exp got ~printer:string_of_int
+
+let ae_bool exp got _test_ctxt =
+  assert_equal exp got ~printer:string_of_bool
+
+let tests = [
+  "ability modifier for score 3 is -4" >::
+  ae (-4) (modifier ~score:3);
+
+  "ability modifier for score 4 is -3" >::
+  ae (-3) (modifier ~score:4);
+
+  "ability modifier for score 5 is -3" >::
+  ae (-3) (modifier ~score: 5);
+
+  "ability modifier for score 6 is -2" >::
+  ae (-2) (modifier ~score: 6);
+
+  "ability modifier for score 7 is -2" >::
+  ae (-2) (modifier ~score: 7);
+
+  "ability modifier for score 8 is -1" >::
+  ae (-1) (modifier ~score: 8);
+
+  "ability modifier for score 9 is -1" >::
+  ae (-1) (modifier ~score: 9);
+
+  "ability modifier for score 10 is 0" >::
+  ae (0) (modifier ~score: 10);
+
+  "ability modifier for score 11 is 0" >::
+  ae (0) (modifier ~score: 11);
+
+  "ability modifier for score 12 is +1" >::
+  ae (1) (modifier ~score: 12);
+
+  "ability modifier for score 13 is +1" >::
+  ae (1) (modifier ~score: 13);
+
+  "ability modifier for score 14 is +2" >::
+  ae (2) (modifier ~score: 14);
+
+  "ability modifier for score 15 is +2" >::
+  ae (2) (modifier ~score: 15);
+
+  "ability modifier for score 16 is +3" >::
+  ae (3) (modifier ~score: 16);
+
+  "ability modifier for score 17 is +3" >::
+  ae (3) (modifier ~score: 17);
+
+  "ability modifier for score 18 is +4" >::
+  ae (4) (modifier ~score: 18);
+
+  "random ability is within range" >:: (fun _test_ctxt ->
+      let value = ability () in
+      ae_bool true (value >= 3 && value <= 18) _test_ctxt;
+    );
+
+  "random character is valid" >:: (fun _test_ctxt ->
+      let c = generate_character () in
+      Printf.printf "Generated character: str=%d, dex=%d, con=%d, int=%d, wis=%d, cha=%d, hp=%d\n"
+        c.strength c.dexterity c.constitution c.intelligence c.wisdom c.charisma c.hitpoints;
+      ae_bool true (c.strength >= 3 && c.strength <= 18) _test_ctxt;
+      ae_bool true (c.dexterity >= 3 && c.dexterity <= 18) _test_ctxt;
+      ae_bool true (c.constitution >= 3 && c.constitution <= 18) _test_ctxt;
+      ae_bool true (c.intelligence >= 3 && c.intelligence <= 18) _test_ctxt;
+      ae_bool true (c.wisdom >= 3 && c.wisdom <= 18) _test_ctxt;
+      ae_bool true (c.charisma >= 3 && c.charisma <= 18) _test_ctxt;
+      ae_bool true (c.hitpoints == 10 + (modifier ~score:c.constitution) ) _test_ctxt;
+    );
+
+  "each ability is only calculated once" >:: (fun _test_ctxt ->
+      let c = generate_character () in
+      let strength1 = c.strength in
+      let strength2 = c.strength in
+      ae (strength1) (strength2) _test_ctxt;
+
+      let dexterity1 = c.dexterity in
+      let dexterity2 = c.dexterity in
+      ae (dexterity1) (dexterity2) _test_ctxt;
+
+      let constitution1 = c.constitution in
+      let constitution2 = c.constitution in
+      ae (constitution1) (constitution2) _test_ctxt;
+
+      let intelligence1 = c.intelligence in
+      let intelligence2 = c.intelligence in
+      ae (intelligence1) (intelligence2) _test_ctxt;
+
+      let wisdom1 = c.wisdom in
+      let wisdom2 = c.wisdom in
+      ae (wisdom1) (wisdom2) _test_ctxt;
+
+      let charisma1 = c.charisma in
+      let charisma2 = c.charisma in
+      ae (charisma1) (charisma2) _test_ctxt;
+
+      let hitpoints1 = c.hitpoints in
+      let hitpoints2 = c.hitpoints in
+      ae (hitpoints1) (hitpoints2) _test_ctxt;
+    );
+]
+
+let () =
+  run_test_tt_main  ("D&D tests" >::: tests)