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paulfioravanti's solution

to Beer Song in the Ruby Track

Published at Jul 13 2018 · 0 comments
Instructions
Test suite
Solution

Recite the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.

Note that not all verses are identical.

99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.

98 bottles of beer on the wall, 98 bottles of beer.
Take one down and pass it around, 97 bottles of beer on the wall.

97 bottles of beer on the wall, 97 bottles of beer.
Take one down and pass it around, 96 bottles of beer on the wall.

96 bottles of beer on the wall, 96 bottles of beer.
Take one down and pass it around, 95 bottles of beer on the wall.

95 bottles of beer on the wall, 95 bottles of beer.
Take one down and pass it around, 94 bottles of beer on the wall.

94 bottles of beer on the wall, 94 bottles of beer.
Take one down and pass it around, 93 bottles of beer on the wall.

93 bottles of beer on the wall, 93 bottles of beer.
Take one down and pass it around, 92 bottles of beer on the wall.

92 bottles of beer on the wall, 92 bottles of beer.
Take one down and pass it around, 91 bottles of beer on the wall.

91 bottles of beer on the wall, 91 bottles of beer.
Take one down and pass it around, 90 bottles of beer on the wall.

90 bottles of beer on the wall, 90 bottles of beer.
Take one down and pass it around, 89 bottles of beer on the wall.

89 bottles of beer on the wall, 89 bottles of beer.
Take one down and pass it around, 88 bottles of beer on the wall.

88 bottles of beer on the wall, 88 bottles of beer.
Take one down and pass it around, 87 bottles of beer on the wall.

87 bottles of beer on the wall, 87 bottles of beer.
Take one down and pass it around, 86 bottles of beer on the wall.

86 bottles of beer on the wall, 86 bottles of beer.
Take one down and pass it around, 85 bottles of beer on the wall.

85 bottles of beer on the wall, 85 bottles of beer.
Take one down and pass it around, 84 bottles of beer on the wall.

84 bottles of beer on the wall, 84 bottles of beer.
Take one down and pass it around, 83 bottles of beer on the wall.

83 bottles of beer on the wall, 83 bottles of beer.
Take one down and pass it around, 82 bottles of beer on the wall.

82 bottles of beer on the wall, 82 bottles of beer.
Take one down and pass it around, 81 bottles of beer on the wall.

81 bottles of beer on the wall, 81 bottles of beer.
Take one down and pass it around, 80 bottles of beer on the wall.

80 bottles of beer on the wall, 80 bottles of beer.
Take one down and pass it around, 79 bottles of beer on the wall.

79 bottles of beer on the wall, 79 bottles of beer.
Take one down and pass it around, 78 bottles of beer on the wall.

78 bottles of beer on the wall, 78 bottles of beer.
Take one down and pass it around, 77 bottles of beer on the wall.

77 bottles of beer on the wall, 77 bottles of beer.
Take one down and pass it around, 76 bottles of beer on the wall.

76 bottles of beer on the wall, 76 bottles of beer.
Take one down and pass it around, 75 bottles of beer on the wall.

75 bottles of beer on the wall, 75 bottles of beer.
Take one down and pass it around, 74 bottles of beer on the wall.

74 bottles of beer on the wall, 74 bottles of beer.
Take one down and pass it around, 73 bottles of beer on the wall.

73 bottles of beer on the wall, 73 bottles of beer.
Take one down and pass it around, 72 bottles of beer on the wall.

72 bottles of beer on the wall, 72 bottles of beer.
Take one down and pass it around, 71 bottles of beer on the wall.

71 bottles of beer on the wall, 71 bottles of beer.
Take one down and pass it around, 70 bottles of beer on the wall.

70 bottles of beer on the wall, 70 bottles of beer.
Take one down and pass it around, 69 bottles of beer on the wall.

69 bottles of beer on the wall, 69 bottles of beer.
Take one down and pass it around, 68 bottles of beer on the wall.

68 bottles of beer on the wall, 68 bottles of beer.
Take one down and pass it around, 67 bottles of beer on the wall.

67 bottles of beer on the wall, 67 bottles of beer.
Take one down and pass it around, 66 bottles of beer on the wall.

66 bottles of beer on the wall, 66 bottles of beer.
Take one down and pass it around, 65 bottles of beer on the wall.

65 bottles of beer on the wall, 65 bottles of beer.
Take one down and pass it around, 64 bottles of beer on the wall.

64 bottles of beer on the wall, 64 bottles of beer.
Take one down and pass it around, 63 bottles of beer on the wall.

63 bottles of beer on the wall, 63 bottles of beer.
Take one down and pass it around, 62 bottles of beer on the wall.

62 bottles of beer on the wall, 62 bottles of beer.
Take one down and pass it around, 61 bottles of beer on the wall.

61 bottles of beer on the wall, 61 bottles of beer.
Take one down and pass it around, 60 bottles of beer on the wall.

60 bottles of beer on the wall, 60 bottles of beer.
Take one down and pass it around, 59 bottles of beer on the wall.

59 bottles of beer on the wall, 59 bottles of beer.
Take one down and pass it around, 58 bottles of beer on the wall.

58 bottles of beer on the wall, 58 bottles of beer.
Take one down and pass it around, 57 bottles of beer on the wall.

57 bottles of beer on the wall, 57 bottles of beer.
Take one down and pass it around, 56 bottles of beer on the wall.

56 bottles of beer on the wall, 56 bottles of beer.
Take one down and pass it around, 55 bottles of beer on the wall.

55 bottles of beer on the wall, 55 bottles of beer.
Take one down and pass it around, 54 bottles of beer on the wall.

54 bottles of beer on the wall, 54 bottles of beer.
Take one down and pass it around, 53 bottles of beer on the wall.

53 bottles of beer on the wall, 53 bottles of beer.
Take one down and pass it around, 52 bottles of beer on the wall.

52 bottles of beer on the wall, 52 bottles of beer.
Take one down and pass it around, 51 bottles of beer on the wall.

51 bottles of beer on the wall, 51 bottles of beer.
Take one down and pass it around, 50 bottles of beer on the wall.

50 bottles of beer on the wall, 50 bottles of beer.
Take one down and pass it around, 49 bottles of beer on the wall.

49 bottles of beer on the wall, 49 bottles of beer.
Take one down and pass it around, 48 bottles of beer on the wall.

48 bottles of beer on the wall, 48 bottles of beer.
Take one down and pass it around, 47 bottles of beer on the wall.

47 bottles of beer on the wall, 47 bottles of beer.
Take one down and pass it around, 46 bottles of beer on the wall.

46 bottles of beer on the wall, 46 bottles of beer.
Take one down and pass it around, 45 bottles of beer on the wall.

45 bottles of beer on the wall, 45 bottles of beer.
Take one down and pass it around, 44 bottles of beer on the wall.

44 bottles of beer on the wall, 44 bottles of beer.
Take one down and pass it around, 43 bottles of beer on the wall.

43 bottles of beer on the wall, 43 bottles of beer.
Take one down and pass it around, 42 bottles of beer on the wall.

42 bottles of beer on the wall, 42 bottles of beer.
Take one down and pass it around, 41 bottles of beer on the wall.

41 bottles of beer on the wall, 41 bottles of beer.
Take one down and pass it around, 40 bottles of beer on the wall.

40 bottles of beer on the wall, 40 bottles of beer.
Take one down and pass it around, 39 bottles of beer on the wall.

39 bottles of beer on the wall, 39 bottles of beer.
Take one down and pass it around, 38 bottles of beer on the wall.

38 bottles of beer on the wall, 38 bottles of beer.
Take one down and pass it around, 37 bottles of beer on the wall.

37 bottles of beer on the wall, 37 bottles of beer.
Take one down and pass it around, 36 bottles of beer on the wall.

36 bottles of beer on the wall, 36 bottles of beer.
Take one down and pass it around, 35 bottles of beer on the wall.

35 bottles of beer on the wall, 35 bottles of beer.
Take one down and pass it around, 34 bottles of beer on the wall.

34 bottles of beer on the wall, 34 bottles of beer.
Take one down and pass it around, 33 bottles of beer on the wall.

33 bottles of beer on the wall, 33 bottles of beer.
Take one down and pass it around, 32 bottles of beer on the wall.

32 bottles of beer on the wall, 32 bottles of beer.
Take one down and pass it around, 31 bottles of beer on the wall.

31 bottles of beer on the wall, 31 bottles of beer.
Take one down and pass it around, 30 bottles of beer on the wall.

30 bottles of beer on the wall, 30 bottles of beer.
Take one down and pass it around, 29 bottles of beer on the wall.

29 bottles of beer on the wall, 29 bottles of beer.
Take one down and pass it around, 28 bottles of beer on the wall.

28 bottles of beer on the wall, 28 bottles of beer.
Take one down and pass it around, 27 bottles of beer on the wall.

27 bottles of beer on the wall, 27 bottles of beer.
Take one down and pass it around, 26 bottles of beer on the wall.

26 bottles of beer on the wall, 26 bottles of beer.
Take one down and pass it around, 25 bottles of beer on the wall.

25 bottles of beer on the wall, 25 bottles of beer.
Take one down and pass it around, 24 bottles of beer on the wall.

24 bottles of beer on the wall, 24 bottles of beer.
Take one down and pass it around, 23 bottles of beer on the wall.

23 bottles of beer on the wall, 23 bottles of beer.
Take one down and pass it around, 22 bottles of beer on the wall.

22 bottles of beer on the wall, 22 bottles of beer.
Take one down and pass it around, 21 bottles of beer on the wall.

21 bottles of beer on the wall, 21 bottles of beer.
Take one down and pass it around, 20 bottles of beer on the wall.

20 bottles of beer on the wall, 20 bottles of beer.
Take one down and pass it around, 19 bottles of beer on the wall.

19 bottles of beer on the wall, 19 bottles of beer.
Take one down and pass it around, 18 bottles of beer on the wall.

18 bottles of beer on the wall, 18 bottles of beer.
Take one down and pass it around, 17 bottles of beer on the wall.

17 bottles of beer on the wall, 17 bottles of beer.
Take one down and pass it around, 16 bottles of beer on the wall.

16 bottles of beer on the wall, 16 bottles of beer.
Take one down and pass it around, 15 bottles of beer on the wall.

15 bottles of beer on the wall, 15 bottles of beer.
Take one down and pass it around, 14 bottles of beer on the wall.

14 bottles of beer on the wall, 14 bottles of beer.
Take one down and pass it around, 13 bottles of beer on the wall.

13 bottles of beer on the wall, 13 bottles of beer.
Take one down and pass it around, 12 bottles of beer on the wall.

12 bottles of beer on the wall, 12 bottles of beer.
Take one down and pass it around, 11 bottles of beer on the wall.

11 bottles of beer on the wall, 11 bottles of beer.
Take one down and pass it around, 10 bottles of beer on the wall.

10 bottles of beer on the wall, 10 bottles of beer.
Take one down and pass it around, 9 bottles of beer on the wall.

9 bottles of beer on the wall, 9 bottles of beer.
Take one down and pass it around, 8 bottles of beer on the wall.

8 bottles of beer on the wall, 8 bottles of beer.
Take one down and pass it around, 7 bottles of beer on the wall.

7 bottles of beer on the wall, 7 bottles of beer.
Take one down and pass it around, 6 bottles of beer on the wall.

6 bottles of beer on the wall, 6 bottles of beer.
Take one down and pass it around, 5 bottles of beer on the wall.

5 bottles of beer on the wall, 5 bottles of beer.
Take one down and pass it around, 4 bottles of beer on the wall.

4 bottles of beer on the wall, 4 bottles of beer.
Take one down and pass it around, 3 bottles of beer on the wall.

3 bottles of beer on the wall, 3 bottles of beer.
Take one down and pass it around, 2 bottles of beer on the wall.

2 bottles of beer on the wall, 2 bottles of beer.
Take one down and pass it around, 1 bottle of beer on the wall.

1 bottle of beer on the wall, 1 bottle of beer.
Take it down and pass it around, no more bottles of beer on the wall.

No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.

For bonus points

Did you get the tests passing and the code clean? If you want to, these are some additional things you could try:

  • Remove as much duplication as you possibly can.
  • Optimize for readability, even if it means introducing duplication.
  • If you've removed all the duplication, do you have a lot of conditionals? Try replacing the conditionals with polymorphism, if it applies in this language. How readable is it?

Then please share your thoughts in a comment on the submission. Did this experiment make the code better? Worse? Did you learn anything from it?


For installation and learning resources, refer to the Ruby resources page.

For running the tests provided, you will need the Minitest gem. Open a terminal window and run the following command to install minitest:

gem install minitest

If you would like color output, you can require 'minitest/pride' in the test file, or note the alternative instruction, below, for running the test file.

Run the tests from the exercise directory using the following command:

ruby beer_song_test.rb

To include color from the command line:

ruby -r minitest/pride beer_song_test.rb

Source

Learn to Program by Chris Pine http://pine.fm/LearnToProgram/?Chapter=06

Submitting Incomplete Solutions

It's possible to submit an incomplete solution so you can see how others have completed the exercise.

beer_song_test.rb

require 'minitest/autorun'
require_relative 'beer_song'

# Common test data version: 2.1.0 87a334d
class BeerSongTest < Minitest::Test
  def test_first_generic_verse
    # skip
    expected = <<~TEXT
    99 bottles of beer on the wall, 99 bottles of beer.
    Take one down and pass it around, 98 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(99, 1)
  end

  def test_last_generic_verse
    skip
    expected = <<~TEXT
    3 bottles of beer on the wall, 3 bottles of beer.
    Take one down and pass it around, 2 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(3, 1)
  end

  def test_verse_with_2_bottles
    skip
    expected = <<~TEXT
    2 bottles of beer on the wall, 2 bottles of beer.
    Take one down and pass it around, 1 bottle of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(2, 1)
  end

  def test_verse_with_1_bottle
    skip
    expected = <<~TEXT
    1 bottle of beer on the wall, 1 bottle of beer.
    Take it down and pass it around, no more bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(1, 1)
  end

  def test_verse_with_0_bottles
    skip
    expected = <<~TEXT
    No more bottles of beer on the wall, no more bottles of beer.
    Go to the store and buy some more, 99 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(0, 1)
  end

  def test_first_two_verses
    skip
    expected = <<~TEXT
    99 bottles of beer on the wall, 99 bottles of beer.
    Take one down and pass it around, 98 bottles of beer on the wall.

    98 bottles of beer on the wall, 98 bottles of beer.
    Take one down and pass it around, 97 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(99, 2)
  end

  def test_last_three_verses
    skip
    expected = <<~TEXT
    2 bottles of beer on the wall, 2 bottles of beer.
    Take one down and pass it around, 1 bottle of beer on the wall.

    1 bottle of beer on the wall, 1 bottle of beer.
    Take it down and pass it around, no more bottles of beer on the wall.

    No more bottles of beer on the wall, no more bottles of beer.
    Go to the store and buy some more, 99 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(2, 3)
  end

  def test_all_verses
    skip
    expected = <<~TEXT
    99 bottles of beer on the wall, 99 bottles of beer.
    Take one down and pass it around, 98 bottles of beer on the wall.

    98 bottles of beer on the wall, 98 bottles of beer.
    Take one down and pass it around, 97 bottles of beer on the wall.

    97 bottles of beer on the wall, 97 bottles of beer.
    Take one down and pass it around, 96 bottles of beer on the wall.

    96 bottles of beer on the wall, 96 bottles of beer.
    Take one down and pass it around, 95 bottles of beer on the wall.

    95 bottles of beer on the wall, 95 bottles of beer.
    Take one down and pass it around, 94 bottles of beer on the wall.

    94 bottles of beer on the wall, 94 bottles of beer.
    Take one down and pass it around, 93 bottles of beer on the wall.

    93 bottles of beer on the wall, 93 bottles of beer.
    Take one down and pass it around, 92 bottles of beer on the wall.

    92 bottles of beer on the wall, 92 bottles of beer.
    Take one down and pass it around, 91 bottles of beer on the wall.

    91 bottles of beer on the wall, 91 bottles of beer.
    Take one down and pass it around, 90 bottles of beer on the wall.

    90 bottles of beer on the wall, 90 bottles of beer.
    Take one down and pass it around, 89 bottles of beer on the wall.

    89 bottles of beer on the wall, 89 bottles of beer.
    Take one down and pass it around, 88 bottles of beer on the wall.

    88 bottles of beer on the wall, 88 bottles of beer.
    Take one down and pass it around, 87 bottles of beer on the wall.

    87 bottles of beer on the wall, 87 bottles of beer.
    Take one down and pass it around, 86 bottles of beer on the wall.

    86 bottles of beer on the wall, 86 bottles of beer.
    Take one down and pass it around, 85 bottles of beer on the wall.

    85 bottles of beer on the wall, 85 bottles of beer.
    Take one down and pass it around, 84 bottles of beer on the wall.

    84 bottles of beer on the wall, 84 bottles of beer.
    Take one down and pass it around, 83 bottles of beer on the wall.

    83 bottles of beer on the wall, 83 bottles of beer.
    Take one down and pass it around, 82 bottles of beer on the wall.

    82 bottles of beer on the wall, 82 bottles of beer.
    Take one down and pass it around, 81 bottles of beer on the wall.

    81 bottles of beer on the wall, 81 bottles of beer.
    Take one down and pass it around, 80 bottles of beer on the wall.

    80 bottles of beer on the wall, 80 bottles of beer.
    Take one down and pass it around, 79 bottles of beer on the wall.

    79 bottles of beer on the wall, 79 bottles of beer.
    Take one down and pass it around, 78 bottles of beer on the wall.

    78 bottles of beer on the wall, 78 bottles of beer.
    Take one down and pass it around, 77 bottles of beer on the wall.

    77 bottles of beer on the wall, 77 bottles of beer.
    Take one down and pass it around, 76 bottles of beer on the wall.

    76 bottles of beer on the wall, 76 bottles of beer.
    Take one down and pass it around, 75 bottles of beer on the wall.

    75 bottles of beer on the wall, 75 bottles of beer.
    Take one down and pass it around, 74 bottles of beer on the wall.

    74 bottles of beer on the wall, 74 bottles of beer.
    Take one down and pass it around, 73 bottles of beer on the wall.

    73 bottles of beer on the wall, 73 bottles of beer.
    Take one down and pass it around, 72 bottles of beer on the wall.

    72 bottles of beer on the wall, 72 bottles of beer.
    Take one down and pass it around, 71 bottles of beer on the wall.

    71 bottles of beer on the wall, 71 bottles of beer.
    Take one down and pass it around, 70 bottles of beer on the wall.

    70 bottles of beer on the wall, 70 bottles of beer.
    Take one down and pass it around, 69 bottles of beer on the wall.

    69 bottles of beer on the wall, 69 bottles of beer.
    Take one down and pass it around, 68 bottles of beer on the wall.

    68 bottles of beer on the wall, 68 bottles of beer.
    Take one down and pass it around, 67 bottles of beer on the wall.

    67 bottles of beer on the wall, 67 bottles of beer.
    Take one down and pass it around, 66 bottles of beer on the wall.

    66 bottles of beer on the wall, 66 bottles of beer.
    Take one down and pass it around, 65 bottles of beer on the wall.

    65 bottles of beer on the wall, 65 bottles of beer.
    Take one down and pass it around, 64 bottles of beer on the wall.

    64 bottles of beer on the wall, 64 bottles of beer.
    Take one down and pass it around, 63 bottles of beer on the wall.

    63 bottles of beer on the wall, 63 bottles of beer.
    Take one down and pass it around, 62 bottles of beer on the wall.

    62 bottles of beer on the wall, 62 bottles of beer.
    Take one down and pass it around, 61 bottles of beer on the wall.

    61 bottles of beer on the wall, 61 bottles of beer.
    Take one down and pass it around, 60 bottles of beer on the wall.

    60 bottles of beer on the wall, 60 bottles of beer.
    Take one down and pass it around, 59 bottles of beer on the wall.

    59 bottles of beer on the wall, 59 bottles of beer.
    Take one down and pass it around, 58 bottles of beer on the wall.

    58 bottles of beer on the wall, 58 bottles of beer.
    Take one down and pass it around, 57 bottles of beer on the wall.

    57 bottles of beer on the wall, 57 bottles of beer.
    Take one down and pass it around, 56 bottles of beer on the wall.

    56 bottles of beer on the wall, 56 bottles of beer.
    Take one down and pass it around, 55 bottles of beer on the wall.

    55 bottles of beer on the wall, 55 bottles of beer.
    Take one down and pass it around, 54 bottles of beer on the wall.

    54 bottles of beer on the wall, 54 bottles of beer.
    Take one down and pass it around, 53 bottles of beer on the wall.

    53 bottles of beer on the wall, 53 bottles of beer.
    Take one down and pass it around, 52 bottles of beer on the wall.

    52 bottles of beer on the wall, 52 bottles of beer.
    Take one down and pass it around, 51 bottles of beer on the wall.

    51 bottles of beer on the wall, 51 bottles of beer.
    Take one down and pass it around, 50 bottles of beer on the wall.

    50 bottles of beer on the wall, 50 bottles of beer.
    Take one down and pass it around, 49 bottles of beer on the wall.

    49 bottles of beer on the wall, 49 bottles of beer.
    Take one down and pass it around, 48 bottles of beer on the wall.

    48 bottles of beer on the wall, 48 bottles of beer.
    Take one down and pass it around, 47 bottles of beer on the wall.

    47 bottles of beer on the wall, 47 bottles of beer.
    Take one down and pass it around, 46 bottles of beer on the wall.

    46 bottles of beer on the wall, 46 bottles of beer.
    Take one down and pass it around, 45 bottles of beer on the wall.

    45 bottles of beer on the wall, 45 bottles of beer.
    Take one down and pass it around, 44 bottles of beer on the wall.

    44 bottles of beer on the wall, 44 bottles of beer.
    Take one down and pass it around, 43 bottles of beer on the wall.

    43 bottles of beer on the wall, 43 bottles of beer.
    Take one down and pass it around, 42 bottles of beer on the wall.

    42 bottles of beer on the wall, 42 bottles of beer.
    Take one down and pass it around, 41 bottles of beer on the wall.

    41 bottles of beer on the wall, 41 bottles of beer.
    Take one down and pass it around, 40 bottles of beer on the wall.

    40 bottles of beer on the wall, 40 bottles of beer.
    Take one down and pass it around, 39 bottles of beer on the wall.

    39 bottles of beer on the wall, 39 bottles of beer.
    Take one down and pass it around, 38 bottles of beer on the wall.

    38 bottles of beer on the wall, 38 bottles of beer.
    Take one down and pass it around, 37 bottles of beer on the wall.

    37 bottles of beer on the wall, 37 bottles of beer.
    Take one down and pass it around, 36 bottles of beer on the wall.

    36 bottles of beer on the wall, 36 bottles of beer.
    Take one down and pass it around, 35 bottles of beer on the wall.

    35 bottles of beer on the wall, 35 bottles of beer.
    Take one down and pass it around, 34 bottles of beer on the wall.

    34 bottles of beer on the wall, 34 bottles of beer.
    Take one down and pass it around, 33 bottles of beer on the wall.

    33 bottles of beer on the wall, 33 bottles of beer.
    Take one down and pass it around, 32 bottles of beer on the wall.

    32 bottles of beer on the wall, 32 bottles of beer.
    Take one down and pass it around, 31 bottles of beer on the wall.

    31 bottles of beer on the wall, 31 bottles of beer.
    Take one down and pass it around, 30 bottles of beer on the wall.

    30 bottles of beer on the wall, 30 bottles of beer.
    Take one down and pass it around, 29 bottles of beer on the wall.

    29 bottles of beer on the wall, 29 bottles of beer.
    Take one down and pass it around, 28 bottles of beer on the wall.

    28 bottles of beer on the wall, 28 bottles of beer.
    Take one down and pass it around, 27 bottles of beer on the wall.

    27 bottles of beer on the wall, 27 bottles of beer.
    Take one down and pass it around, 26 bottles of beer on the wall.

    26 bottles of beer on the wall, 26 bottles of beer.
    Take one down and pass it around, 25 bottles of beer on the wall.

    25 bottles of beer on the wall, 25 bottles of beer.
    Take one down and pass it around, 24 bottles of beer on the wall.

    24 bottles of beer on the wall, 24 bottles of beer.
    Take one down and pass it around, 23 bottles of beer on the wall.

    23 bottles of beer on the wall, 23 bottles of beer.
    Take one down and pass it around, 22 bottles of beer on the wall.

    22 bottles of beer on the wall, 22 bottles of beer.
    Take one down and pass it around, 21 bottles of beer on the wall.

    21 bottles of beer on the wall, 21 bottles of beer.
    Take one down and pass it around, 20 bottles of beer on the wall.

    20 bottles of beer on the wall, 20 bottles of beer.
    Take one down and pass it around, 19 bottles of beer on the wall.

    19 bottles of beer on the wall, 19 bottles of beer.
    Take one down and pass it around, 18 bottles of beer on the wall.

    18 bottles of beer on the wall, 18 bottles of beer.
    Take one down and pass it around, 17 bottles of beer on the wall.

    17 bottles of beer on the wall, 17 bottles of beer.
    Take one down and pass it around, 16 bottles of beer on the wall.

    16 bottles of beer on the wall, 16 bottles of beer.
    Take one down and pass it around, 15 bottles of beer on the wall.

    15 bottles of beer on the wall, 15 bottles of beer.
    Take one down and pass it around, 14 bottles of beer on the wall.

    14 bottles of beer on the wall, 14 bottles of beer.
    Take one down and pass it around, 13 bottles of beer on the wall.

    13 bottles of beer on the wall, 13 bottles of beer.
    Take one down and pass it around, 12 bottles of beer on the wall.

    12 bottles of beer on the wall, 12 bottles of beer.
    Take one down and pass it around, 11 bottles of beer on the wall.

    11 bottles of beer on the wall, 11 bottles of beer.
    Take one down and pass it around, 10 bottles of beer on the wall.

    10 bottles of beer on the wall, 10 bottles of beer.
    Take one down and pass it around, 9 bottles of beer on the wall.

    9 bottles of beer on the wall, 9 bottles of beer.
    Take one down and pass it around, 8 bottles of beer on the wall.

    8 bottles of beer on the wall, 8 bottles of beer.
    Take one down and pass it around, 7 bottles of beer on the wall.

    7 bottles of beer on the wall, 7 bottles of beer.
    Take one down and pass it around, 6 bottles of beer on the wall.

    6 bottles of beer on the wall, 6 bottles of beer.
    Take one down and pass it around, 5 bottles of beer on the wall.

    5 bottles of beer on the wall, 5 bottles of beer.
    Take one down and pass it around, 4 bottles of beer on the wall.

    4 bottles of beer on the wall, 4 bottles of beer.
    Take one down and pass it around, 3 bottles of beer on the wall.

    3 bottles of beer on the wall, 3 bottles of beer.
    Take one down and pass it around, 2 bottles of beer on the wall.

    2 bottles of beer on the wall, 2 bottles of beer.
    Take one down and pass it around, 1 bottle of beer on the wall.

    1 bottle of beer on the wall, 1 bottle of beer.
    Take it down and pass it around, no more bottles of beer on the wall.

    No more bottles of beer on the wall, no more bottles of beer.
    Go to the store and buy some more, 99 bottles of beer on the wall.
    TEXT
    assert_equal expected, BeerSong.recite(99, 100)
  end
end
# frozen_string_literal: true

module BeerSong
  AMOUNT_OF_BEER = "%<amount>s %<container>s of beer"
  private_constant :AMOUNT_OF_BEER
  BEER_ON_WALL = lambda do |amount, container: "bottles"|
    "#{format(AMOUNT_OF_BEER, amount: amount, container: container)} "\
    "on the wall"
  end
  private_constant :BEER_ON_WALL
  END_VERSE_NUMBER = lambda do |start_verse_number, num_verses|
    start_verse_number - num_verses + 1
  end
  private_constant :END_VERSE_NUMBER
  LINE_1 = lambda do |amount, container: "bottles"|
    "#{BEER_ON_WALL.call(amount.to_s.capitalize, container: container)}, "\
    "#{format(AMOUNT_OF_BEER, amount: amount, container: container)}."
  end
  private_constant :LINE_1
  LINE_2 = lambda do |amount, container: "bottles", subject: "one"|
    "Take #{subject} down and pass it around, "\
    "#{BEER_ON_WALL.call(amount, container: container)}."
  end
  private_constant :LINE_2
  GENERIC_VERSE = lambda do |amount|
    <<~VERSE
      #{LINE_1.call(amount)}
      #{LINE_2.call(amount - 1)}
    VERSE
  end
  private_constant :GENERIC_VERSE
  VERSE_2 =
    <<~VERSE
      #{LINE_1.call(2)}
      #{LINE_2.call(1, container: "bottle")}
    VERSE
  private_constant :VERSE_2
  VERSE_1 =
    <<~VERSE
      #{LINE_1.call(1, container: "bottle")}
      #{LINE_2.call("no more", subject: "it")}
    VERSE
  private_constant :VERSE_1
  VERSE_0 =
    <<~VERSE
      #{LINE_1.call("no more")}
      Go to the store and buy some more, #{BEER_ON_WALL.call(99)}.
    VERSE
  private_constant :VERSE_0
  VERSES =
    Hash.new { |_hash, key| GENERIC_VERSE.call(key) }.tap do |hash|
      hash[2] = VERSE_2
      hash[1] = VERSE_1
      hash[0] = VERSE_0
    end
  private_constant :VERSES

  module_function

  def recite(start_verse_number, num_verses)
    end_verse_number =
      END_VERSE_NUMBER.call(start_verse_number, num_verses)

    start_verse_number
      .downto(end_verse_number)
      .map(&VERSES)
      .join("\n")
  end
end

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