Add twelve-days exercise (#518)

* Add twelve-days exercise

* Generate each verse

config.json

@@ -650,6 +650,14 @@
           "exception_handling"
         ]
       },
+      {
+        "slug": "twelve-days",
+        "name": "Twelve Days",
+        "uuid": "51ea559b-818b-47a9-91af-53772c46e171",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "word-count",
         "name": "Word Count",

exercises/practice/twelve-days/.busted

@@ -0,0 +1,5 @@
+return {
+  default = {
+    ROOT = { '.' }
+  }
+}

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

@@ -0,0 +1,36 @@
+# 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

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "twelve-days.lua"
+    ],
+    "test": [
+      "twelve-days_spec.lua"
+    ],
+    "example": [
+      ".meta/example.lua"
+    ]
+  },
+  "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.lua

@@ -0,0 +1,48 @@
+local function recite_verse(verse)
+  local ordinals = {
+    'first',
+    'second',
+    'third',
+    'fourth',
+    'fifth',
+    'sixth',
+    'seventh',
+    'eighth',
+    'ninth',
+    'tenth',
+    'eleventh',
+    'twelfth'
+  }
+
+  local gifts = {
+    'a Partridge in a Pear Tree.',
+    'two Turtle Doves, and',
+    '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,'
+  }
+
+  local result = { 'On the', ordinals[verse], 'day of Christmas my true love gave to me:' }
+  for index = verse, 1, -1 do
+    table.insert(result, gifts[index])
+  end
+
+  return table.concat(result, ' ')
+end
+
+local function recite(start_verse, end_verse)
+  local result = {}
+  for verse = start_verse, end_verse do
+    table.insert(result, recite_verse(verse))
+  end
+  return result
+end
+
+return { recite = recite }

exercises/practice/twelve-days/.meta/spec_generator.lua

@@ -0,0 +1,26 @@
+local map = function(t, f)
+  local mapped = {}
+  for i, v in ipairs(t) do
+    mapped[i] = f(v)
+  end
+  return mapped
+end
+
+local function render_song(lines)
+  return table.concat(map(lines, function(line)
+    return '\'' .. line .. '\''
+  end), ',\n')
+end
+
+return {
+  module_name = 'twelve_days',
+
+  generate_test = function(case)
+    local template = [[
+      local expected = {
+        %s
+      }
+      assert.are.same(expected, twelve_days.recite(%d, %d))]]
+    return template:format(render_song(case.expected), case.input.startVerse, case.input.endVerse)
+  end
+}

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

@@ -0,0 +1,55 @@
+# 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/twelve-days.lua

@@ -0,0 +1,5 @@
+local function recite(start_verse, end_verse)
+
+end
+
+return { recite = recite }

exercises/practice/twelve-days/twelve-days_spec.lua

@@ -0,0 +1,125 @@
+local twelve_days = require('twelve-days')
+
+describe('twelve-days', function()
+  describe('verse', function()
+    it('first day a partridge in a pear tree', function()
+      local expected = { 'On the first day of Christmas my true love gave to me: a Partridge in a Pear Tree.' }
+      assert.are.same(expected, twelve_days.recite(1, 1))
+    end)
+
+    it('second day two turtle doves', function()
+      local expected = {
+        'On the second day of Christmas my true love gave to me: two Turtle Doves, and a Partridge in a Pear Tree.'
+      }
+      assert.are.same(expected, twelve_days.recite(2, 2))
+    end)
+
+    it('third day three french hens', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(3, 3))
+    end)
+
+    it('fourth day four calling birds', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(4, 4))
+    end)
+
+    it('fifth day five gold rings', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(5, 5))
+    end)
+
+    it('sixth day six geese-a-laying', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(6, 6))
+    end)
+
+    it('seventh day seven swans-a-swimming', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(7, 7))
+    end)
+
+    it('eighth day eight maids-a-milking', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(8, 8))
+    end)
+
+    it('ninth day nine ladies dancing', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(9, 9))
+    end)
+
+    it('tenth day ten lords-a-leaping', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(10, 10))
+    end)
+
+    it('eleventh day eleven pipers piping', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(11, 11))
+    end)
+
+    it('twelfth day twelve drummers drumming', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(12, 12))
+    end)
+  end)
+
+  describe('lyrics', function()
+    it('recites first three verses of the song', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(1, 3))
+    end)
+
+    it('recites three verses from the middle of the song', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(4, 6))
+    end)
+
+    it('recites the whole song', function()
+      local expected = {
+        '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.'
+      }
+      assert.are.same(expected, twelve_days.recite(1, 12))
+    end)
+  end)
+end)