Вказівки
Наше завдання в цій вправі - написати код, який повертає текст пісні «The Twelve Days of Christmas».
«The Twelve Days of Christmas» - поширена англійська різдвяна колядка.
Кожен наступний куплет пісні будується на попередньому.
Текст, який повертає наш код, має точно збігатися з повним текстом пісні, наведеним нижче.
Текст пісні
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.
Підказки
Потрібно реалізувати функцію recite, яка виводить текст пісні «The Twelve Days of Christmas». Можна скористатися наданою сигнатурою, якщо є сумніви щодо типів, але не варто дозволяти їй обмежувати творчість.
Ця вправа працює з текстовими даними. З історичних причин тип String у Haskell позначає те саме, що [Char], тобто масив символів. Для ефективнішої роботи з текстовими даними можна використовувати тип Text.
Як необовʼязкове доповнення до цієї вправи, можна
import qualified Data.Text as T
import Data.Text (Text)
- написати, наприклад,
recite :: Int -> Int -> [Text] і звертатися до комбінаторів Data.Text як, наприклад, T.pack.
- пошукати документацію для
Data.Text.
- замінити всі входження
String на Text у TwelveDays.hs, тобто:
recite :: Int -> Int -> [Text]
Ця частина цілком необовʼязкова.
