Add dnd-character exercise (#376)

config.json

@@ -825,6 +825,14 @@
         "prerequisites": [],
         "difficulty": 4
       },
+      {
+        "slug": "dnd-character",
+        "name": "D&D Character",
+        "uuid": "8c617fa4-5c2f-4be3-b7dc-8f8bf8214326",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "binary-search",
         "name": "Binary Search",

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": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "dnd-character.R"
+    ],
+    "test": [
+      "test_dnd-character.R"
+    ],
+    "example": [
+      ".meta/example.R"
+    ]
+  },
+  "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.R

@@ -0,0 +1,24 @@
+modifier <- function(score) {
+  (score - 10) %/% 2
+}
+
+ability <- function() {
+  sample(1:6, 4, replace = TRUE) |> sort() |> tail(n = 3) |> sum()
+}
+
+new_character <- function() {
+  constitution <- ability()
+
+  structure(
+    list(
+      strength = ability(),
+      dexterity = ability(),
+      intelligence = ability(),
+      wisdom = ability(),
+      charisma = ability(),
+      constitution = constitution,
+      hitpoints = 10 + modifier(constitution)
+    ),
+    class = "character"
+  )
+}

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/dnd-character.R

@@ -0,0 +1,11 @@
+modifier <- function(score) {
+
+}
+
+ability <- function() {
+
+}
+
+new_character <- function() {
+
+}

exercises/practice/dnd-character/test_dnd-character.R

@@ -0,0 +1,99 @@
+source("./dnd-character.R")
+library(testthat)
+
+test_that("Ability modifier for score 3 is -4", {
+  expect_equal(modifier(3), -4)
+})
+
+test_that("Ability modifier for score 4 is -3", {
+  expect_equal(modifier(4), -3)
+})
+
+test_that("Ability modifier for score 5 is -3", {
+  expect_equal(modifier(5), -3)
+})
+
+test_that("Ability modifier for score 6 is -2", {
+  expect_equal(modifier(6), -2)
+})
+
+test_that("Ability modifier for score 7 is -2", {
+  expect_equal(modifier(7), -2)
+})
+
+test_that("Ability modifier for score 8 is -1", {
+  expect_equal(modifier(8), -1)
+})
+
+test_that("Ability modifier for score 9 is -1", {
+  expect_equal(modifier(9), -1)
+})
+
+test_that("Ability modifier for score 10 is 0", {
+  expect_equal(modifier(10), 0)
+})
+
+test_that("Ability modifier for score 11 is 0", {
+  expect_equal(modifier(11), 0)
+})
+
+test_that("Ability modifier for score 12 is +1", {
+  expect_equal(modifier(12), 1)
+})
+
+test_that("Ability modifier for score 13 is +1", {
+  expect_equal(modifier(13), 1)
+})
+
+test_that("Ability modifier for score 14 is +2", {
+  expect_equal(modifier(14), 2)
+})
+
+test_that("Ability modifier for score 15 is +2", {
+  expect_equal(modifier(15), 2)
+})
+
+test_that("Ability modifier for score 16 is +3", {
+  expect_equal(modifier(16), 3)
+})
+
+test_that("Ability modifier for score 17 is +3", {
+  expect_equal(modifier(17), 3)
+})
+
+test_that("Ability modifier for score 18 is +4", {
+  expect_equal(modifier(18), 4)
+})
+
+test_that("Random ability is within range", {
+  for (i in 1:10) {
+    expect_true(ability() %in% 3:18)
+  }
+})
+
+test_that("Random character is valid", {
+  for (i in 1:10) {
+    character <- new_character()
+    expect_s3_class(character, "character")
+    expect_true(character$strength %in% 3:18)
+    expect_true(character$dexterity %in% 3:18)
+    expect_true(character$constitution %in% 3:18)
+    expect_true(character$intelligence %in% 3:18)
+    expect_true(character$wisdom %in% 3:18)
+    expect_true(character$charisma %in% 3:18)
+    expect_equal(character$hitpoints, 10 + modifier(character$constitution))
+  }
+})
+
+test_that("Each ability is only calculated once", {
+  for (i in 1:10) {
+    character <- new_character()
+    expect_equal(character$strength, character$strength)
+    expect_equal(character$dexterity, character$dexterity)
+    expect_equal(character$constitution, character$constitution)
+    expect_equal(character$intelligence, character$intelligence)
+    expect_equal(character$wisdom, character$wisdom)
+    expect_equal(character$charisma, character$charisma)
+    expect_equal(character$hitpoints, character$hitpoints)
+  }
+})