Add twelve-days exercise (#371)

config.json

@@ -785,6 +785,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "twelve-days",
+        "name": "Twelve Days",
+        "uuid": "da138984-77d2-49a9-a553-11d2448b7bb2",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "house",
         "name": "House",

exercises/practice/twelve-days/.docs/instructions.md

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+# Instructions
+
+Your task in this exercise is to write code that returns the lyrics of the song: "The Twelve Days of Christmas."
+
+"The Twelve Days of Christmas" is a common English Christmas carol.
+Each subsequent verse of the song builds on the previous verse.
+
+The lyrics your code returns should _exactly_ match the full song text shown below.
+
+## Lyrics
+
+```text
+On the first day of Christmas my true love gave to me: a Partridge in a Pear Tree.
+
+On the second day of Christmas my true love gave to me: two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the third day of Christmas my true love gave to me: three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the fourth day of Christmas my true love gave to me: four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the fifth day of Christmas my true love gave to me: five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the sixth day of Christmas my true love gave to me: six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the seventh day of Christmas my true love gave to me: seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the eighth day of Christmas my true love gave to me: eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the ninth day of Christmas my true love gave to me: nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the tenth day of Christmas my true love gave to me: ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the eleventh day of Christmas my true love gave to me: eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+
+On the twelfth day of Christmas my true love gave to me: twelve Drummers Drumming, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.
+```

exercises/practice/twelve-days/.meta/config.json

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+{
+  "authors": [
+    "erikschierboom"
+  ],
+  "files": {
+    "solution": [
+      "twelve-days.R"
+    ],
+    "test": [
+      "test_twelve-days.R"
+    ],
+    "example": [
+      ".meta/example.R"
+    ]
+  },
+  "blurb": "Output the lyrics to 'The Twelve Days of Christmas'.",
+  "source": "Wikipedia",
+  "source_url": "https://en.wikipedia.org/wiki/The_Twelve_Days_of_Christmas_(song)"
+}

exercises/practice/twelve-days/.meta/example.R

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+subjects <- c(
+  "a Partridge in a Pear Tree", "two Turtle Doves", "three French Hens",
+  "four Calling Birds", "five Gold Rings", "six Geese-a-Laying",
+  "seven Swans-a-Swimming", "eight Maids-a-Milking", "nine Ladies Dancing",
+  "ten Lords-a-Leaping", "eleven Pipers Piping", "twelve Drummers Drumming"
+)
+
+days <- c(
+  "first", "second", "third", "fourth", "fifth", "sixth",
+  "seventh", "eighth", "ninth", "tenth", "eleventh", "twelfth"
+)
+
+verse <- function(number) {
+  gifts <- subjects[number:1]
+  if (number > 1) {
+    gifts[length(gifts)] <- paste("and", gifts[length(gifts)])
+  }
+
+  paste(
+    "On the ", days[number], " day of Christmas my true love gave to me: ",
+    paste0(gifts, collapse = ", "), ".",
+    sep = ""
+  )
+}
+
+recite <- function(start_verse, end_verse) {
+  sapply(start_verse:end_verse, verse)
+}

exercises/practice/twelve-days/.meta/tests.toml

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+# 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.
+
+[c0b5a5e6-c89d-49b1-a6b2-9f523bff33f7]
+description = "verse -> first day a partridge in a pear tree"
+
+[1c64508a-df3d-420a-b8e1-fe408847854a]
+description = "verse -> second day two turtle doves"
+
+[a919e09c-75b2-4e64-bb23-de4a692060a8]
+description = "verse -> third day three french hens"
+
+[9bed8631-ec60-4894-a3bb-4f0ec9fbe68d]
+description = "verse -> fourth day four calling birds"
+
+[cf1024f0-73b6-4545-be57-e9cea565289a]
+description = "verse -> fifth day five gold rings"
+
+[50bd3393-868a-4f24-a618-68df3d02ff04]
+description = "verse -> sixth day six geese-a-laying"
+
+[8f29638c-9bf1-4680-94be-e8b84e4ade83]
+description = "verse -> seventh day seven swans-a-swimming"
+
+[7038d6e1-e377-47ad-8c37-10670a05bc05]
+description = "verse -> eighth day eight maids-a-milking"
+
+[37a800a6-7a56-4352-8d72-0f51eb37cfe8]
+description = "verse -> ninth day nine ladies dancing"
+
+[10b158aa-49ff-4b2d-afc3-13af9133510d]
+description = "verse -> tenth day ten lords-a-leaping"
+
+[08d7d453-f2ba-478d-8df0-d39ea6a4f457]
+description = "verse -> eleventh day eleven pipers piping"
+
+[0620fea7-1704-4e48-b557-c05bf43967f0]
+description = "verse -> twelfth day twelve drummers drumming"
+
+[da8b9013-b1e8-49df-b6ef-ddec0219e398]
+description = "lyrics -> recites first three verses of the song"
+
+[c095af0d-3137-4653-ad32-bfb899eda24c]
+description = "lyrics -> recites three verses from the middle of the song"
+
+[20921bc9-cc52-4627-80b3-198cbbfcf9b7]
+description = "lyrics -> recites the whole song"

exercises/practice/twelve-days/test_twelve-days.R

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+source("./twelve-days.R") # nolint
+library(testthat)
+
+test_that("First day a partridge in a pear tree", {
+  expected <- c("On the first day of Christmas my true love gave to me: a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(1, 1), expected)
+})
+
+test_that("Second day two turtle doves", {
+  expected <- c("On the second day of Christmas my true love gave to me: two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(2, 2), expected)
+})
+
+test_that("Third day three french hens", {
+  expected <- c("On the third day of Christmas my true love gave to me: three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(3, 3), expected)
+})
+
+test_that("Fourth day four calling birds", {
+  expected <- c("On the fourth day of Christmas my true love gave to me: four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(4, 4), expected)
+})
+
+test_that("Fifth day five gold rings", {
+  expected <- c("On the fifth day of Christmas my true love gave to me: five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(5, 5), expected)
+})
+
+test_that("Sixth day six geese-a-laying", {
+  expected <- c("On the sixth day of Christmas my true love gave to me: six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(6, 6), expected)
+})
+
+test_that("Seventh day seven swans-a-swimming", {
+  expected <- c("On the seventh day of Christmas my true love gave to me: seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(7, 7), expected)
+})
+
+test_that("Eighth day eight maids-a-milking", {
+  expected <- c("On the eighth day of Christmas my true love gave to me: eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(8, 8), expected)
+})
+
+test_that("Ninth day nine ladies dancing", {
+  expected <- c("On the ninth day of Christmas my true love gave to me: nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(9, 9), expected)
+})
+
+test_that("Tenth day ten lords-a-leaping", {
+  expected <- c("On the tenth day of Christmas my true love gave to me: ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(10, 10), expected)
+})
+
+test_that("Eleventh day eleven pipers piping", {
+  expected <- c("On the eleventh day of Christmas my true love gave to me: eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(11, 11), expected)
+})
+
+test_that("Twelfth day twelve drummers drumming", {
+  expected <- c("On the twelfth day of Christmas my true love gave to me: twelve Drummers Drumming, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.") # nolint
+  expect_equal(recite(12, 12), expected)
+})
+
+test_that("Recites first three verses of the song", {
+  expected <-
+    c(
+      "On the first day of Christmas my true love gave to me: a Partridge in a Pear Tree.", # nolint
+      "On the second day of Christmas my true love gave to me: two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the third day of Christmas my true love gave to me: three French Hens, two Turtle Doves, and a Partridge in a Pear Tree." # nolint
+    )
+  expect_equal(recite(1, 3), expected)
+})
+
+test_that("Recites three verses from the middle of the song", {
+  expected <-
+    c(
+      "On the fourth day of Christmas my true love gave to me: four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the fifth day of Christmas my true love gave to me: five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the sixth day of Christmas my true love gave to me: six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree." # nolint
+    )
+  expect_equal(recite(4, 6), expected)
+})
+
+test_that("Recites the whole song", {
+  expected <-
+    c(
+      "On the first day of Christmas my true love gave to me: a Partridge in a Pear Tree.", # nolint
+      "On the second day of Christmas my true love gave to me: two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the third day of Christmas my true love gave to me: three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the fourth day of Christmas my true love gave to me: four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the fifth day of Christmas my true love gave to me: five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the sixth day of Christmas my true love gave to me: six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the seventh day of Christmas my true love gave to me: seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the eighth day of Christmas my true love gave to me: eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the ninth day of Christmas my true love gave to me: nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the tenth day of Christmas my true love gave to me: ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the eleventh day of Christmas my true love gave to me: eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree.", # nolint
+      "On the twelfth day of Christmas my true love gave to me: twelve Drummers Drumming, eleven Pipers Piping, ten Lords-a-Leaping, nine Ladies Dancing, eight Maids-a-Milking, seven Swans-a-Swimming, six Geese-a-Laying, five Gold Rings, four Calling Birds, three French Hens, two Turtle Doves, and a Partridge in a Pear Tree." # nolint
+    )
+  expect_equal(recite(1, 12), expected)
+})

exercises/practice/twelve-days/twelve-days.R

@@ -0,0 +1,3 @@
+recite <- function(start_verse, end_verse) {
+
+}